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  • Blom, Alice
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Olsson, Susanna
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Improved Patient Admission Planning - A Discrete Event Simulation Study at the Department of Pulmonary Medicine, Linköping University Hospital2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Swedish health care system plays a vital role in satisfying the citizens’ demands for quality health care services. To deliver the right services in time in a hospital, an efficient admission plan is required, but this can be difficult to achieve. The Department of Pulmonary Medicine at the University Hospital in Linköping needs a better admission plan for their patients. In the department, the patient demand does not match the capacity, which leads to overcrowding at the ward. The aim of this thesis is to improve the admission plan of patients for the ward at the Department of Pulmonary Medicine by using discrete event simulation. To fulfil the aim, a simulation study is performed to understand how the system is working, where the problems emerged and how to prevent overcrowding. Different experiments are performed to check what could improve the admission plan at the ward. The results from this study shows that an improvement of the admission plan could be reached by better cooperation between involved units, improved documentation at the Department, a queue system of patients based on medical priorities and changed number of care beds. These solutions can prevent overcrowding and deliver health care services in time.

  • Mangs, Ludvig
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Computer-assisted fracture reduction in an orthopaedic pre-operative planning workflow2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report presents three implementations for solving 3D puzzles of fractured bones: two semi-automatic ones and one which is automatic. These are compared using qualitative as well as quantitative tests to find out if less interaction can yield equal or better results. Qualitative tests are performed on real clinical data from CT-scans. A model created in Blender is used for quantitative tests. Test results have shown that each implementation has its own strengths and weaknesses which can make them usable for different types of fractures. It may be possible to combine automatic solutions and manual ones to increase the number of solvable cases. The conclusion is that it is possible to reduce fractures with less user interaction and still get equal or better results, but it depends on the fracture case as well as the user.

  • Erlandsson, Tobias
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Hallström, Gustav
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Audial Support for Visual Dense Data Display2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report presents an application developed for evaluating the possible benefits of using audial support in a visualization application. A hypothesis is presented where the idea is that sonification might help users perceive densities in data-sets with large amounts of data points. The application presents a scatterplot and a parallel coordinates plot. To both plots audial support is added where the amplitude of the sound is used for representing the amount of points in different areas of the plots. The method is evaluated through user studies where ability to find maximum points, finding equal densities and appreciation of the sounds is investigated. Quantitative and qualitative results show improvements when finding maximum points in tight clusters both in parallel coordinates and scatter plots. This is a first step when investigating this area of visualization spurring further research.

  • Fransson, Anton
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Granqvist, Michael
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Improving the inventory control of spare parts at Nextjet AB2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Nextjet anser att de har ett ofördelaktigt beställnings- och lagerhållningssystem av reservdelar, och mest problem är det med o-ringarna och skruvarna. Beställning sker oftast först när ett behov uppstår vilket ibland kan leda till att plan blir stående och därmed att potentiella intäkter uteblir. I denna studie har en lagerstyrningsstrategi framställts för o-ringarna och skruvarna i Nextjets reservdelslager. Under studiens gång genomfördes en artikelklassificering av o-ringarna och skruvarna på grund av att många av artiklarna hade en liknande karaktäristik. En lagerstyrningsmetod har sedan upprättats för vardera grupp som uppstått. De metoder som använts var beställningspunkt, återfyllnadsnivå och lot-for-lot. Resultatet av lagerstyrningsstrategierna har lett till att både kapitalbindningen och lagernivåerna har minskat i jämfört med nuläget samtidigt som risken för brist har minskat drastiskt. Lagernivåerna minskar med drygt 1000 artiklar och den maximala kapitalbindningen minskar med nästan 100 000 SEK i jämförelse med vad den är i nuläget.

  • Lindström, Anton
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Design and implementation of a power distribution network for control equipment for electric vehicle charging2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis treats the design and implementation of a power distribution network for a controller PCB for controlling charging of electric vehicles. The controller PCB is powered by mains power, and thus needs both AC to DC conversion and DC to DC conversion in order to operate. The thesis focuses on the design of an isolated flyback topology AC to DC converter, while also describing the design and implementation of the DC to DC converters needed for the controller PCB to operate.

    The work started with some theoretical study, and then progressed into designing the converters. The AC to DC and the DC to DC converters where designed in parallel. After the design phase was complete the converters where implemented on PCBs for evaluation. The evaluation of the AC to DC converter involved evaluation of several different transformers from different suppliers, as well as evaluation of the circuit design itself. All converters designed proved functional after evaluation.

  • Strandstedt, Jonas
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Multi-Volume Rendering in OpenSpace Using A-Buffers for Space Weather Visualizations2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The work described in this thesis is part of the initial development of the open-source visualization software OpenSpace, a collaborative project between Linköping University (LiU), the National Aeronautics and Space Administration (NASA) and the American Museum of Natural History (AMNH). The report covers the background and implementation of a rendering system that enables OpenSpace to interactively visualize multiple overlapping space weather events. The system works much like a Deferred Renderer by rendering all objects once and then resolves the final image in a second rendering step. To render a mix of opaque and translucent objects and volumes simultaneously, order-independent transparency solutions are implemented. Performance is compared against traditional methods and possible improvements are discussed. The implemented rendering system is currently powering the OpenSpace visualizations, this gives scientists an interactive tool for studying multiple space weather events, education and public outreach.

  • Nordin, Johan
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Realistic virtual hands: Exploring how appearance affects the sense of embodiment2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    How would you react if you looked down on your hands and they had been replaced with someone else’s hands?

    This is the case for virtual reality applications that incorporate virtual hands, all applications have their own representation of virtual hands but none takes the user’s own hand into account. For this reason, we have created a framework that allows to customize geometric features of existing hand models towards a more personal hand representation.

    We have designed and conducted an experiment to study sense of ownership of four virtual hand representations. It was found that participants pay attention to size of the hand and the length of the fingers but do not necessarily consider the virtual hands as their own. We believe that a virtual hand that truly creates the impression of one’s own hand may benefit educational, training or rehabilitation virtual reality applications. In order to achieve this, our conclusion is that a certain extent of size, shape and appearance of the user’s hand need to be considered.

  • Bladin, Kalle
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Broberg, Erik
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Design and Implementation of an Out-of-Core Globe Rendering System Using Multiple Map Services2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis focuses on the design and implementation of a software system enabling out-of-core rendering of multiple map datasets mapped on virtual globes around our solar system. Challenges such as precision, accuracy, curvature and massive datasets were considered. The result is a globe visualization software using a chunked level of detail approach for rendering. The software can render texture layers of various sorts to aid in scientific visualization on top of height mapped geometry, yielding accurate visualizations rendered at interactive frame rates. The project was conducted at the American Museum of Natural History (AMNH), New York and serves the goal of implementing a planetary visualization software to aid in public presentations and bringing space science to the public. The work is part of the development of the software OpenSpace, which is the result of a collaboration between Linköping University, AMNH and the National Aeronautics and Space Administration (NASA) among others.

  • Tornberg, Aron
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Wennström, Sofia
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Development and Research in Previsualization for Advanced Live-Action on CGI Film Recording2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A major disadvantage of shooting on green screen with CGI is that the director cannot see or interact with the virtual elements in the scene and thus get a realistic view of how the end result will look like, and also not being able to make changes as necessary by moving objects and actors around during the shooting session. This disadvantage can be mitigated by the use of previsualization where the director is given a rough take of what the final cut will look like by combining the filmed material with the virtual environment in real-time. This master’s thesis work aims to come up with solutions for improving the film studio Stiller Studios’s previsualization system. This involves a review and integration of game engines for previsualization in a motion control green screen studio, a camera calibration process with blur detection and automatic selection of images as well as research into camera tracking and depth compositing.

  • Hansson, Alexander
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Morän, Martin
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Implementation of simulator based continuation training for Swedish ATS-units2017Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Inom flygbranschen är säkerhet av högsta prioritet och det vidtas proaktiva åtgärder inom samtliga organisationer och branschområden för att säkerställa att högsta möjliga nivå uppnås. För LFV som tillhandahåller flygtrafiktjänst och som även är en certifierad utbildningsorganisation är säkerställandet av kompetens inom den operativa driften en stor del i det ständigt pågående säkerhetsarbetet. Denna kompetenssäkring för operativ personal inom torn-sektorn är nu under utvärdering där målet är att skapa en centraliserad styr- och planeringsmodell för att uppnå en mer standardiserad och kontrollerad process. Detta förändringsarbete är en följd av införandet av EU-förordning 340/2015 som trädde i kraft under 2015, där kraven på kompetenssäkring blivit hårdare.

    En undersökning av huruvida kompetenssäkring kan utföras i en centraliserad simulerad miljö, för att kunna säkerställa de nya kraven i EU-förordning 340/2015, har genomförts och analyserats, baserad på åsikter från olika involverade flygplatsenheter, och genom att studera dansk modell för centraliserad kompetenssäkring. Fördelar och nackdelar med att centralisera och förflytta kompetenssäkringen till en simulerad miljö har utvärderats, och en heuristisk schemametodik och ett schemaförslag på hur den centraliserade simuleringen skulle kunna implementeras för de inblandade flygplatserna har tagits fram och analyserats.

    Studien visar att införandet av en centraliserad simulerad miljö för kompetenssäkring är möjlig med exempelvis ett mer enhetligt och standardiserat genomförande som  resultat. Vidare innebär det även större möjligheter till anpassningsbarhet av kompetenssäkringen.

    Schemaförslaget visar att samtliga enheters kompetenssäkringsbehov är tillgodosett. Fallstudien, analys samt schemaförslag anses kunna ligga till grund för vidare utveckling av kompetenssäkringsprocessen för LFV.

  • Engström, Amanda
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Allocation of a consolidation centre for construction materials in Norrköping2017Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    I Norrköping ökade antalet invånare med 4000 mellan åren 2005 och 2010 samtidigt som en bostadsbrist uppstod 2009. För att försöka komma tillrätta med bostadsbristen byggs det allt mer och många av dessa nya bostäder byggs inne i stadskärnan. Problem som kan uppstå i samband med byggnationer i innerstaden är bl.a. att områden ibland spärras av och att tunga transporter rör sig i trånga utrymmen vilket blir en säkerhetsrisk för t.ex. fotgängare. Detta har lett till att Norrköpings kommun har övervägt frågan om att införa en samlastningscentral för byggmaterial för att minska de tunga transporterna. Målet med denna studie är att baserat på ett antal kriterier ta fram olika alternativplatser och sedan analysera dessa utifrån ett antal aspekter för att ta fram den lämpligaste platsen. Aspekterna valdes baserat på vad som ansågs vara viktigast men går även att styrka med hjälp av litteratur. Det valdes även olika aspekter för att eventuellt kunna lyfta fram olika styrkor och svagheter hos de olika platserna. För att kunna analysera en plats genererades ett antal rutter från varje plats till en fast referenspunkt i stadskärnan och denna punkt var densamma för alla platser. Dessa rutter genererades med hjälp av Google Maps och fördes sedan in i GIS-programmet. Programmet som användes var QGIS och med hjälp av t.ex. olycksstatistik gick det att ta fram vilka rutter som var de mest olycksdrabbade. Det som analyserades i QGIS var bostadsområden, skolor, olycksstatistik och framkomlighet. Sedan rangordnades de olika rutterna från bäst till sämst och poängsattes från 1–10. Ett medelvärde togs fram för varje plats där ruttpoängerna dividerades med antalet rutter från just den platsen. Sedan rangordnades platserna baserat på medelvärdet där den bästa fick poängen 4 och den sämsta poängen 1. Sedan multipliceras denna poäng med den tilldelade faktorn för varje aspekt. Därmed får alla aspekter spela in i resultatet och den platsen med den högsta poängen blir den bästa placeringen. Det visade sig att den plats som är bäst sett ur säkerhet är plats 3: Linköpingsvägen och sett ur framkomlighet var plats 1 bäst. Den platsen som var bäst sett från effektivitet var plats 4: Söderleden 106. Baserat på alla aspekter blir plats 1: Händelö gård 3 den bästa. Därmed är slutsatsen att plats 1 är den bästa totalt men beroende på vad som anses vara viktigast går det att få fram olika resultat och skulle andra aspekter användas skulle antagligen ett annat resultat fås.

  • Lenner, Andreas
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Zawadzki, Sebastian
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Placement of work stations for optimized and efficient cooperation in the Östgöta control center2017Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Det finns olika sätt att öka kapaciteten hos en flygledare. En av de är att göra samordningar mer effektiva. Samordningar sker idag via datalänk eller verbalt, då genom telefonsamordning eller face-to-face. Det finns även icke verbala samordningar där bara kroppsspråk står för en del av kommunikationen. På en kontrollcentral utförs många samordningar och informationsdelningar mellan flygledare. Detta görs för att kunna hålla en hög säkerhet men ändå arbeta på ett effektivt sätt. Östgöta kontrollcentral, ÖKC, har undersökts för att se om informationsdelningen kan bli effektivare samt om en flygledarassistent kan stötta två flygledare samtidigt. Med hjälp av en teoretisk referensram och litteraturstudie har det visat sig att bland annat Lean production kan appliceras på området för att utvärdera ÖKC. Författarna har observerat den operativa verksamheten på ÖKC och samlat data som i sin tur ligger till grund för de mätningar som gjorts. Därefter har ett alternativt ÖKC tagits fram med förankring i teorin om hur kontrollcentraler bör se ut för en bra social samverkan och teamwork. Utifrån data från observationen är informationssträckan som information inne på ÖKC måste färdas 150,8 meter. Detta mätetal är undersökningens viktigaste mätetal och visar att alternativet har motsvarande 130,5 meter informationssträcka, vilket ger en minskning med 20,3 meter.

  • Nordmark, Oskar
    Linköping University, Department of Electrical Engineering, Computer Engineering.
    Turbo Code Performance Analysis Using Hardware Acceleration2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The upcoming 5G mobile communications system promises to enable use cases requiring ultra-reliable and low latency communications. Researchers therefore require more detailed information about aspects such as channel coding performance at very low block error rates. The simulations needed to obtain such results are very time consuming and this poses achallenge to studying the problem. This thesis investigates the use of hardware acceleration for performing fast simulations of turbo code performance. Special interest is taken in investigating different methods for generating normally distributed noise based on pseudorandom number generator algorithms executed in DSP:s. A comparison is also done regarding how well different simulator program structures utilize the hardware. Results show that even a simple program for utilizing parallel DSP:s can achieve good usage of hardware accelerators and enable fast simulations. It is also shown that for the studied process the bottleneck is the conversion of hard bits to soft bits with addition of normally distributed noise. It is indicated that methods for noise generation which do not adhere to a true normal distribution can further speed up this process and yet yield simulation quality comparable to methods adhering to a true Gaussian distribution. Overall, it is show that the proposed use of hardware acceleration in combination with the DSP software simulator program can in a reasonable time frame generate results for turbo code performance at block error rates as low as 10−9.

  • Lind, Benjamin
    Linköping University, Department of Electrical Engineering, Computer Vision.
    Artificial Neural Networks for Image Improvement2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    After a digital photo has been taken by a camera, it can be manipulated to be more appealing. Two ways of doing that are to reduce noise and to increase the saturation. With time and skills in an image manipulating program, this is usually done by hand. In this thesis, automatic image improvement based on artificial neural networks is explored and evaluated qualitatively and quantitatively. A new approach, which builds on an existing method for colorizing gray scale images is presented and its performance compared both to simpler methods and the state of the art in image denoising. Saturation is lowered and noise added to original images, which the methods receive as inputs to improve upon. The new method is shown to improve in some cases but not all, depending on the image and how it was modified before given to the method.

  • Ngaruye, Innocent
    et al.
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, Faculty of Science & Engineering. Department of Mathematics, College of Science and Technology, University of Rwanda.
    von Rosen, Dietrich
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, Faculty of Science & Engineering. Department of Energy and Technology, Swedish University of Agricultural Sciences.
    Singull, Martin
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, Faculty of Science & Engineering.
    Small area estimation with missing data using a multivariate linear random effects model2017Report (Other academic)
    Abstract [en]

    In this article small area estimation with multivariate data that follow a monotonic missing sample pattern is addressed. Random effects growth curve models with covariates are formulated. A likelihood based approach is proposed for estimation of the unknown  parameters. Moreover, the prediction of random effects and predicted small area means are also discussed.

  • Jonsson, Robert
    et al.
    Linköping University, Department for Studies of Social Change and Culture, Centre for Municipality Studies – CKS. Linköping University, Faculty of Arts and Sciences.
    Syssner, Josefina
    Linköping University, Department for Studies of Social Change and Culture, Centre for Municipality Studies – CKS. Linköping University, Faculty of Arts and Sciences.
    Demografianpassad infrastruktur?: Om hantering av anläggnings-tillgångar i kommuner med minskande befolkningsunderlag2016In: Nordisk Administrativt Tidsskrift, E-ISSN 2246-1310, Vol. 93, no 3, 45-64 p.Article in journal (Refereed)
    Abstract [sv]

    Vi har i en rad studier undersökt huruvida effekter och policyimplikationer av långvarig befolkningsminskning beskrivs i kommunala styrdokument. Denna artikel bygger på en delstudie vars övergripande syfte varit att öka förståelsen för hur man i krympande kommuner hanterar och planerar för sina anläggningstillgångar. Vi har här intresserat oss specifikt för huruvida kommunerna i budget och årsredovisningar beskriver sina anläggningstillgångar avseende status och underhåll. Vi har också intresserat oss för i vilken mån kommunerna i dessa dokument drar slutsatser om vilka konsekvenser en förändrad demografi har för hur kommunerna ska planera för sina anläggningstillgångar. Syftet med vår art ikel är därmed att diskutera i vilken mån kommunernas budgetar och årsredovisningar är sammanhang där kommunerna beskriver sina anläggningstillgångar avseende status och underhåll, och huruvida kommunerna här beskriver strategier för hur anläggningstillgångarna ska kunna anpassas till en ny demografisk situation. Strategier kan finnas i andra dokument, men budget och årsredovisningar är för kommunerna tvingande dokument som underställs kommunfullmäktige varje år. I dessa dokument ska kommunerna inför medborgarna redogöra på vilket sätt de svarar upp mot kraven på god ekonomisk hushållning. Anläggningstillgångarnas status, underhåll och demografianpassning har dessutom uppenbara ekonomiska implikationer, vilket gör att budget och årsredovisning torde vara de styrdokument där kommunen i första hand beskriver dessa förhållanden.

    Vår ambition har varit att undersöka kommuner som har ett minskande befolkningsunderlag, men som i övrigt har varierande förutsättningar och karaktär. Studien baseras därför på ett systematiskt urval av kommuner, där urvalet baserades på geo-grafiskt läge, närhet till större tätort samt befolkningsstorlek.

  • Norin, Gustav
    Linköping University, Department of Electrical Engineering, Automatic Control.
    Detecting External Forces on an Autonomous Lawnmowing Robot with Inertial, Wheel Speed and Wheel Motor Current Measurements2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Lockowandt, Karin
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Parsing and Validation of Modelica Models Utilising Fault Diagnosis2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Models have become an indispensable tool within most industrial sectors and are used to reduce costs, enhance the performance of a system etc. The computer support within modelling is extensive, whereof the programming language Modelica is eminent, especially for multi-domain models. Dymola, a commercial program, is built on Modelica and is foremost used for simulation purposes, but many applications for which models are useful are not supported by Dymola. Instead other tools, e.g. Matlab, could be used to exploit the full potential of a model, which means that it first would be needed to be translated. This master's thesis examines one of the possible ways to accomplish this. Specifically the possibility to translate Modelica-models via an XML file, generated by Dymola, is examined. The structure and content of this file is explored, and based thereupon a software is implemented in Python, which successfully translates the models constituting the base for this thesis. Specifically the method was developed on a model of a sub-system of Saab 39 Gripen air-plane.

    Besides porting models between different languages, it is of great interest to determine how well a model describes the system on which it is based. Hence a new method for model validation is developed using the Matlab Fault Diagnosis Toolbox, which also determines the Matlab syntax of the Modelica translation. The novelty with the developed method, compared to traditional model validation methods, is that it is equation based. It is meant to point out specifically which equations are poorly fitted to validation data. On a simple example model the method was successfully used to isolate a poorly fitted equation. This is accomplished by introducing faults to the equations and generating residuals, based on sets of over-determined equations. As a measure of the modelling error the estimation error of the simulated residuals is used, which are weighted together depending on the fault properties of the residuals.

  • Dannetun, Victor
    Linköping University, Department of Computer and Information Science.
    Job Schedule and Cloud Auto-Scaling for Repetitive Computation2016Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
  • Wänström, Johan
    Linköping University, Department for Studies of Social Change and Culture, Centre for Municipality Studies – CKS. Linköping University, Faculty of Arts and Sciences.
    En stark regionalmakt?: Kommunstorlekens betydelse för förväntningarna på och erfarenheterna av det regionala utvecklingsarbetet2017Report (Other academic)
    Abstract [sv]

    2015 bildades nya regioner i sex län i Sverige och under de närmaste fyra åren planeras det för flera ytterligare regionbildningsprocesser. Ett centralt motiv till de regionbildningsprocesserna är att skapa bättre förutsättningar för ett effektivt regionalt utvecklingsarbete. Bland annat finns det stora förhoppningar på ett väl utvecklat samarbete mellan region- och primärkommunerna i det regionala utvecklingsarbetet. Det väcker frågan om förhoppningarna om ett starkt samarbete mellan region- och primärkommunerna har förverkligats i de län där regionbildningsprocesser har genomförts.

    Syftet med den här rapporten är att beskriva kommunernas förväntningar på och erfarenheter av samarbetet mellan region- och primärkommuner i det regionala utvecklingsarbetet. Skiljde sig de förväntningarna åt mellan olika kommuner och upplevde kommunerna att förväntningarna hade infriats? Rapportens empiriska material utgörs av djupintervjuer med 22 kommunstyrelseordföranden och kommunchefer i 16 kommuner fördelade på fyra län.

    Studien pekar på att stora kommuner generellt sett upplever ett mindre behov av en stark regional samordning och en stark regional kraft i det regionala utvecklingsarbetet. För många mindre kommuner utgör emellertid en stark regional samordning och en stark regional kraft ett viktigt instrument i deras ambitioner att utvecklas och växa – eller åtminstone att sluta och krympa. Att infria förhoppningarna och förväntningarna från alla primärkommuner framstår därför som en stor utmaning för de nya regionkommunerna. Den gamla och ständigt återkommande sanningen att Sverige, men också varje län, består av kommuner med olika yttre förutsättningar påverkar således i allra högsta grad förväntningarna på och förutsättningarna för det regionala utvecklingsarbetet. 

  • Renholm, Anna
    et al.
    Linköping University, Department of Thematic Studies.
    Svensson, Ida
    Linköping University, Department of Thematic Studies.
    Plastproblematiken ur miljöorganisationers perspektiv: En kvalitativ textanalys- och intervjustudie2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this essay have the environmental organizations, Naturskyddsföreningen, Greenpeace Sweden and Världsnaturfonden WWF’s perspective onthe plastic issue and working methods regarding this issue been identified and analyzed. This has been done using a qualitative content analysis aswell as a supplementary semistructured interview study. The three environmental organizations’ perspective on the plastic issue is different foreach organization. Naturskyddsföreningen sees on the plastic issue primarily from a perspective where the focus is on the negative effects thatplastic and the chemicals in plastic contribute to the human health, where children’s health is the main focus area. Greenpeace Sweden sees on theplastic issue from a perspective where the focus is on both the dangerous effects that plastic and the chemicals in plastic contribute to the humanhealth, but also it’s negative effects on the marine ecosystems and the marine species. Världsnaturfonden WWF sees on the plastic issue from aperspective where the focus is on the negative effects the plastic and the chemicals in plastic have on the marine ecosystems and the marinespecies. All of the three organizations uses working methods where they conduct campaigns, develop evidence and conduct dialogs withpoliticians. The organization that differs mainly from the two other organizations regarding working methods is Greenpeace Sweden. GreenpeaceSweden also uses actions, protests and demonstrations, primarily against companies. Naturskyddsföreningen and Världsnaturfonden WWF arenon-activist organizations and do not use these kinds of working methods. What all three of these organizations aim for and want to achieve is achanged legislation in which politicians and the industry take a greater responsibility for the plastic issue

  • Elofsson Bjesse, Jonna
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change.
    Gräntz, Sara
    Linköping University, Department of Thematic Studies, Tema Environmental Change.
    Sustainable Livelihoods: Household adaptation strategies to climate change and Gender structures: - A case study in two mid-hills agrarian mountain communities of Nepal2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study aims to investigate the influence of livelihood strategies and gender structures for climate change adaptation among rural households in two mid-hills agrarian mountain communities in Nepal. The Sustainable Livelihoods (SL) framework has been used to provide a holistic and micro-level perspective of livelihood strategies. The method used was qualitative semi-structured interviews to reach respondents views, opinions and feelings of their reality and experiences. Findings suggest climate change may increase smallholder agriculture households’ vulnerability in rural mid-hills mountain areas of Nepal, where women as a group are disproportionately affected; the success of livelihood diversification as a autonomous adaptation strategy to climate change is dependent on local opportunities and socioeconomic aspects and must be understood in the broader context, not just related to climate change; and livelihood strategies do not necessarily present equal opportunities for sustainable livelihoods for men and women, as it may even increase existing structures of gender inequalities.  

  • Hallman, Emil
    et al.
    Linköping University, Department of Social and Welfare Studies.
    Haglund, Magnus
    Linköping University, Department of Social and Welfare Studies.
    Digitaliseringen av undervisningen: En forskningsöversikt över effekterna av digitaliseringskoncepten 1:1 och ASL2017Student paper other, 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna forskningsöversikt behandlar digitaliseringen av undervisningen utifrån koncepten 1:1 (en dator per elev) och ASL (att skriva sig till läsning). Vi har via databassökning och manuell sökning tagit del av relevant litteratur som vi sedan gjort en kvalitativ innehållsanalys på. Vi behandlar vilka effekter koncepten enligt forskningen har för elever och lärare. Det råder ingen allmän konsensus om detta, då forskningsresultat pekar mot både positiva och negativa effekter. Vi söker därför även i litteraturen efter faktorer som visat sig gynna goda resultat. De faktorer vi funnit är struktur av fortbildning och stöd, av både teknisk och didaktisk karaktär, samt ett sociokulturellt arbetssätt.Genomgående i den litteratur vi läst efterfrågas mer forskning på området. Detta inkluderar både kritisk granskning av den forskning som nu finns och ny forskning som tar hänsyn till fler aspekter av de begrepp som berörs och som innefattar en vidgad kunskapssyn.

  • Saaid, Sara
    et al.
    Linköping University, Department of Social and Welfare Studies.
    Zornic, Edina
    Linköping University, Department of Social and Welfare Studies.
    Hur föräldrar kan påverka barns uppfattningar, synsätt och beteenden: En strukturerad litteraturstudie med fokus på etnisk och kulturell bakgrund samt fördomar.2017Student paper other, 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna konsumtionsuppsats syfte är att analysera forskning om hur föräldrars syn på omvärlden kan påverka ett barns beteende, synsätt och attityder med fokus på etnisk och kulturell bakgrund samt fördomar. Tre frågeställningar användes som utgångspunkter över vad forskningen säger om hur barn påverkas av framförallt föräldrar men även andra individer i ett barns omgivning. Studien tar upp flera centrala faktorer som påverkar barns identitetsutveckling bland annat uppfostran, socialisation, hur synen på omvärlden överförs från föräldrarna, vilka konsekvenser ett barn ställs inför om det har en sådan inställning till samhället samt hur lärare kan motverka dessa inställningar hos ett barn. Genom analys av internationell och nationell forskning visar studien att föräldrars ageranden och synsätt, direkt och indirekt, påverkar barns olika beteenden. 

  • Magnuson, Martin
    Department of Physics, Uppsala University, Box 530, S-75121 Uppsala, Sweden.
    An Electron Beam Heated Evaporation Source1994Report (Other academic)
    Abstract [en]

    An electron beam evaporator has been assembled, tested and used for deposition of thin nickel films. Flux and deposition rates has been measured with an oscillating quartz crystal monitor (QCM), an ion sensor wire, and visible deposition on a mirror on front of the evaporator. A thin nickel rod of 2 mm diameter was found to improve the pressure in comparison to a 6-mm nickel rod. The flux was typically 3-4 Angstroms per minute during the test, but other flux rates can easily be achieved by changing the filament current and the acceleration voltage.

  • Public defence: 2017-06-16 13:15 Ada Lovelace, B-hus, Linköping
    Aghighi, Meysam
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Computational Complexity of some Optimization Problems in Planning2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Automated planning is known to be computationally hard in the general case. Propositional planning is PSPACE-complete and first-order planning is undecidable. One method for analyzing the computational complexity of planning is to study restricted subsets of planning instances, with the aim of differentiating instances with varying complexity. We use this methodology for studying the computational complexity of planning. Finding new tractable (i.e. polynomial-time solvable) problems has been a particularly important goal for researchers in the area. The reason behind this is not only to differentiate between easy and hard planning instances, but also to use polynomial-time solvable instances in order to construct better heuristic functions and improve planners. We identify a new class of tractable cost-optimal planning instances by restricting the causal graph. We study the computational complexity of oversubscription planning (such as the net-benefit problem) under various restrictions and reveal strong connections with classical planning. Inspired by this, we present a method for compiling oversubscription planning problems into the ordinary plan existence problem. We further study the parameterized complexity of cost-optimal and net-benefit planning under the same restrictions and show that the choice of numeric domain for the action costs has a great impact on the parameterized complexity. We finally consider the parameterized complexity of certain problems related to partial-order planning. In some applications, less restricted plans than total-order plans are needed. Therefore, a partial-order plan is being used instead. When dealing with partial-order plans, one important question is how to achieve optimal partial order plans, i.e. having the highest degree of freedom according to some notion of flexibility. We study several optimization problems for partial-order plans, such as finding a minimum deordering or reordering, and finding the minimum parallel execution length.

    List of papers
    1. Oversubscription planning: Complexity and compilability
    Open this publication in new window or tab >>Oversubscription planning: Complexity and compilability
    2014 (English)In: Proceedings of the Twenty-Eighth AAAI Conference on Artificial Intelligence, AI Access Foundation , 2014, Vol. 3, 2221-2227 p.Conference paper (Refereed)
    Abstract [en]

    Many real-world planning problems are oversubscription problems where all goals are not simultaneously achievable and the planner needs to find a feasible subset. We present complexity results for the so-called partial satisfaction and net benefit problems under various restrictions; this extends previous work by van den Briel et al. Our results reveal strong connections between these problems and with classical planning. We also present a method for efficiently compiling oversubscription problems into the ordinary plan existence problem; this can be viewed as a continuation of earlier work by Keyder and Geffner.

    Place, publisher, year, edition, pages
    AI Access Foundation, 2014
    National Category
    Computer and Information Science
    Identifiers
    urn:nbn:se:liu:diva-116727 (URN)2-s2.0-84908192348 (ScopusID)9781577356790 (ISBN)
    Conference
    28th AAAI Conference on Artificial Intelligence, AAAI 2014, 26th Innovative Applications of Artificial Intelligence Conference, IAAI 2014 and the 5th Symposium on Educational Advances in Artificial Intelligence, EAAI 2014
    Available from: 2015-04-09 Created: 2015-04-02 Last updated: 2017-05-17
    2. Tractable Cost-Optimal Planning over Restricted Polytree Causal Graphs
    Open this publication in new window or tab >>Tractable Cost-Optimal Planning over Restricted Polytree Causal Graphs
    2015 (English)In: Proceedings of the Twenty-Ninth AAAI Conference on Artificial Intelligence, AAAI Press, 2015Conference paper (Refereed)
    Abstract [en]

    Causal graphs are widely used to analyze the complexity of planning problems. Many tractable classes have been identified with their aid and state-of-the-art heuristics have been derived by exploiting such classes. In particular, Katz and Keyder have studied causal graphs that are hourglasses (which is a generalization of forks and inverted-forks) and shown that the corresponding cost-optimal planning problem is tractable under certain restrictions. We continue this work by studying polytrees (which is a generalization of hourglasses) under similar restrictions. We prove tractability of cost-optimal planning by providing an algorithm based on a novel notion of variable isomorphism. Our algorithm also sheds light on the k-consistency procedure for identifying unsolvable planning instances. We speculate that this may, at least partially, explain why merge-and-shrink heuristics have been successful for recognizing unsolvable instances.

    Place, publisher, year, edition, pages
    AAAI Press, 2015
    Series
    Proceedings of the AAAI Conference on Artificial Intelligence, ISSN 2159-5399, E-ISSN 2374-3468
    Keyword
    automated planning, causal graph, polynomial-time algorithm, cost-optimal planning, polytree
    National Category
    Computer Systems
    Identifiers
    urn:nbn:se:liu:diva-118729 (URN)978-1-57735-703-2 (ISBN)
    Conference
    29th AAAI Conference on Artificial Intelligence (AAAI-15), January 25–30, Austin, TX, USA
    Funder
    CUGS (National Graduate School in Computer Science)
    Available from: 2015-06-03 Created: 2015-06-03 Last updated: 2017-05-17
    3. Cost-optimal and Net-benefit Planning--A Parameterised Complexity View
    Open this publication in new window or tab >>Cost-optimal and Net-benefit Planning--A Parameterised Complexity View
    2015 (English)In: 24th International Joint Conference on Artificial Intelligence (IJCAI-15), 2015Conference paper (Refereed)
    Abstract [en]

    Cost-optimal planning (COP) uses action costs and asks for a minimum-cost plan. It is sometimes assumed that there is no harm in using actions with zero cost or rational cost. Classical complexity analysis does not contradict this assumption; planning is PSPACE-complete regardless of whether action costs are positive or non-negative, integer or rational. We thus apply parameterised complexity analysis to shed more light on this issue. Our main results are the following. COP is W[2]-complete for positive integer costs, i.e. it is no harder than finding a minimum-length plan, but it is para-NPhard if the costs are non-negative integers or positive rationals. This is a very strong indication that the latter cases are substantially harder. Net-benefit planning (NBP) additionally assigns goal utilities and asks for a plan with maximum difference between its utility and its cost. NBP is para-NP-hard even when action costs and utilities are positive integers, suggesting that it is harder than COP. In addition, we also analyse a large number of subclasses, using both the PUBS restrictions and restricting the number of preconditions and effects.

    National Category
    Transport Systems and Logistics
    Identifiers
    urn:nbn:se:liu:diva-128181 (URN)
    Conference
    24th International Joint Conference on Artificial Intelligence (IJCAI-15)
    Funder
    CUGS (National Graduate School in Computer Science), 1054Swedish Research Council, 621- 2014-4086
    Available from: 2016-05-20 Created: 2016-05-20 Last updated: 2017-05-17Bibliographically approved
    4. A Multi-parameter Complexity Analysis of Cost-optimal and Net-benefit Planning
    Open this publication in new window or tab >>A Multi-parameter Complexity Analysis of Cost-optimal and Net-benefit Planning
    2016 (English)Conference paper (Refereed)
    Abstract [en]

    Aghighi and Bäckström have previously studied cost-optimal planning (COP) and net-benefit planning (NBP) for three action cost domains: the positive integers (Z_+), the non-negative integers (Z_0) and the positive rationals (Q_+). These were indistinguishable under standard complexity analysis for both problems, but separated for COP using parameterised complexity analysis. With the plan cost, k, as parameter, COP was W[2]-complete for Z_+, but para-NP-hard for both Z_0 and Q_+, i.e. presumably much harder. NBP was para-NP-hard for all three domains, thus remaining unseparable. We continue by considering combinations with several additional parameters and also the non-negative rationals (Q_0). Examples of new parameters are the plan length, l, and the largest denominator of the action costs, d. Our findings include: (1) COP remains W[2]-hard for all domains, even if combining all parameters; (2) COP for Z_0 is in W[2] for the combined parameter {k,l}; (3) COP for Q_+ is in W[2] for {k,d} and (4) COP for Q_0 is in W[2] for {k,d,l}. For NBP we consider further additional parameters, where the most crucial one for reducing complexity is the sum of variable utilities. Our results help to understand the previous results, eg. the separation between Z_+ and Q_+ for COP, and to refine the previous connections with empirical findings.

    Place, publisher, year, edition, pages
    AAAI Press, 2016
    Keyword
    cost-optimal planning, parameterised complexity, numeric domains
    National Category
    Computer Systems
    Identifiers
    urn:nbn:se:liu:diva-136278 (URN)
    Conference
    Twenty-Sixth International Conference on Automated Planning and Scheduling (ICAPS-16)
    Available from: 2017-04-05 Created: 2017-04-05 Last updated: 2017-05-17
    5. Plan Reordering and Parallel Execution -- A Parameterized Complexity View
    Open this publication in new window or tab >>Plan Reordering and Parallel Execution -- A Parameterized Complexity View
    2017 (English)Conference paper (Refereed)
    Abstract [en]

    Bäckström has previously studied a number of optimization problems for partial-order plans, like finding a minimum deordering (MCD) or reordering (MCR), and finding the minimum parallel execution length (PPL), which are all NP-complete. We revisit these problems, but applying parameterized complexity analysis rather than standard complexity analysis. We consider various parameters, including both the original and desired size of the plan order, as well as its width and height. Our findings include that MCD and MCR are W[2]-hard and in W[P] when parameterized with the desired order size, and MCD is fixed-parameter tractable (fpt) when parameterized with the original order size. Problem PPL is fpt if parameterized with the size of the non-concurrency relation, but para-NP-hard in most other cases. We also consider this problem when the number (k) of agents, or processors, is restricted, finding that this number is a crucial parameter; this problem is fixed-parameter tractable with the order size, the parallel execution length and k as parameter, but para-NP-hard without k as parameter.

    Place, publisher, year, edition, pages
    AAAI Press, 2017
    Keyword
    Partially ordered plan, Parameterized complexity, Complexity of planning, Plan reordering, Parallel plan execution
    National Category
    Computer Systems
    Identifiers
    urn:nbn:se:liu:diva-136279 (URN)
    Conference
    Thirty-First AAAI Conference on Artificial Intelligence (AAAI-17)
    Available from: 2017-04-05 Created: 2017-04-05 Last updated: 2017-05-17Bibliographically approved
  • Public defence: 2017-06-16 10:15 C3, C-huset, Linköping
    Björnsson, Andreas
    Linköping University, Department of Management and Engineering, Manufacturing Engineering. Linköping University, Faculty of Science & Engineering.
    Automated layup and forming of prepreg laminates2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Composite materials like carbon fiber-reinforced polymers (CFRPs) present highly appealing material properties, as they can combine high strength with low weight. In aerospace applications, these properties help to realize lightweight designs that can reduce fuel consumption. Within the aerospace industry, the use of these types of materials has increased drastically with the introduction of a new generation of commercial aircraft. This increased use of CFRP drives a need to develop more rational manufacturing methods.

    For aerospace applications, CFRP products are commonly manufactured from a material called prepreg, which consists of carbon fibers impregnated with uncured polymer resin. There are two dominant manufacturing technologies for automated manufacturing using prepreg, automated tape layup and automated fiber placement. These two technologies are not suitable for all types of products, either due to technical limitations or a combination of high investment costs and low productivity. Automation alternatives to the two dominant technologies have been attempted, but have so far had limited impact. Due to the lack of automation alternatives, manual manufacturing methods are commonly employed for the manufacturing of complex-shaped products in low to medium manufacturing volumes.

    The research presented in this thesis aims to explore how automated manufacturing systems for the manufacturing of complex CFRP products made from prepreg can be designed so that they meet the needs and requirements of the aerospace industry, and are suitable for low to medium production volumes. In order to explore the area, a demonstrator-centered research approach has been employed. A number of demonstrators, in the form of automated manufacturing cells, have been designed and tested with industrial and research partners. The demonstrators have been used to identify key methods and technologies that enable this type of manufacturing, and to analyze some of these methods and technologies in detail. The demonstrators have also been used to map challenges that affect the development of enabling methods and technologies.

    Automated manufacturing of products with complex shapes can be simplified by dividing the process into two steps. Thin layers of prepreg are laid up on top of each other to form flat laminates that are formed to the desired shape in subsequent forming operations. The key methods and technologies required to automate such a system are methods and technologies for automated prepreg layup, the automated removal of backing paper and the forming of complex shapes. The main challenges are the low structural rigidity and tacky nature of prepreg materials, the extensive quality requirements in the aerospace industry and the need for the systems to handle a wide array of prepreg shapes.

    The demonstrators show that it is possible to automate the manufacturing of complexshaped products using automated layup and forming of prepreg laminates. Tests using the demonstrators indicate that it is possible to meet the quality requirements that apply to manual manufacturing of similar products.

    List of papers
    1. Composite Manufacturing: How Improvement Work Might Lead to Renewed Product Validation
    Open this publication in new window or tab >>Composite Manufacturing: How Improvement Work Might Lead to Renewed Product Validation
    2012 (English)In: Proceedings of the 5th International Swedish Production Symposium / [ed] Mats Björkman, 2012, 505-513 p.Conference paper (Refereed)
    Abstract [en]

    High-performance polymer composites are mainly used in applications where the benefits of high strength and low weight justify the high material and manufacturing costs. Many of these applications are found today in the aerospace, space and defense industries. Most of today’s commonly used manufacturing methods within this area are highly labor intensive. Furthermore, the quality requirements from the customers require a high level of process control. The purpose of this paper is to explore how changes that are introduced in order to improve productivity in a manufacturing system are managed, particularly with regard to who takes the decision to implement a change and how a change is validated. The study is based on qualitative interviews performed at several companies that manufacture composite components for the aerospace, space and defense sectors. The findings show that the responsibility for deciding to implement a change and the need for validating it are based on many diverse and interconnected factors. Therefore, it is difficult to construct guidelines for early assessment of the scope and cost of a proposed change. Hence each individual change request must be evaluated on its own. The study also shows that the validation process can be adapted to a level that is based on the type of change. In addition, it highlights that control over process parameters in manufacturing is essential.

    Keyword
    composite manufacturing, validation, change request management
    National Category
    Production Engineering, Human Work Science and Ergonomics
    Identifiers
    urn:nbn:se:liu:diva-85268 (URN)978-91-7519-752-4 (ISBN)
    Conference
    5th International Swedish Production Symposium (SPS 2012), 6-8 November 2012, Linköping, Sweden
    Available from: 2012-11-14 Created: 2012-11-14 Last updated: 2017-05-17
    2. Automated Removal of Prepreg Backing Paper - A Sticky Problem
    Open this publication in new window or tab >>Automated Removal of Prepreg Backing Paper - A Sticky Problem
    2013 (English)In: Proceedings of the SAE 2013, Aerotech Congress and Exhibition, 24th-26th September 2013, Montreal,Canada, 2013Conference paper (Refereed)
    Abstract [en]

    Automated solutions for manufacturing composite products based on prepreg often imply Automatic Fiber Placement or Automatic Tape Laying. These systems are generally associated with huge investments. For certain manufacturing applications it is interesting to investigate alternatives to find simpler and less costly automation. One example of an automated system could be the use of a standard industrial robot to pick single prepreg plies from an automated cutting machine and stack them to form a plane laminate. This paper is based on a case illustrating a product from the aircraft manufacturing industry. The case will demonstrate a pick and place concept on a general level and illustrate challenges that must be solved. The challenge selected to be the main focus for this paper is an automated process for backing paper removal. A literature review of different gripping technologies reveals several interesting technologies, and the most promising are tested for backing paper removal. The tests show that an automated removal process can be designed by using standard vacuum grippers in combination with mechanical clamping grippers. In order to lift the backing paper with a vacuum gripper an initial separation between the backing paper and prepreg is needed. This separation is most easily mechanically induced by bending the material. The proposed solution for automatic backing paper removal can be integrated in a manufacturing cell for manufacturing of the studied product.

    Keyword
    composite manufacturing, automation, prepreg, gripping technology
    National Category
    Production Engineering, Human Work Science and Ergonomics
    Identifiers
    urn:nbn:se:liu:diva-99344 (URN)10.4271/2013-01-2289 (DOI)
    Conference
    SAE 2013 Aerotech Congress and Exhibition, September 24-26, 2013, Montréal, Quebec, Canada
    Note

    SAE Technical Paper 2013-01-2289

    Available from: 2013-10-16 Created: 2013-10-16 Last updated: 2017-05-17Bibliographically approved
    3. Automation of Composite Manufacturing Using Off-the-shelf Solutions, Three Cases from the Aerospace Industry
    Open this publication in new window or tab >>Automation of Composite Manufacturing Using Off-the-shelf Solutions, Three Cases from the Aerospace Industry
    2015 (English)In: Proceedings of the 20th International Conference on Composite Materials, 2015Conference paper (Other academic)
    Abstract [en]

    With an increased use of composite materials follows a need for rational, cost-efficient manufacturing processes. This paper explores how off-the-shelf solutions, developed for other purposes than composite manufacturing, can be used to build systems for automated composite manufacturing. Three demonstrators, each of them dealing with a specific type of material and all of them representing different manufacturing technologies for automated composite manufacturing, are presented and analyzed to find aspects that affect the ability to use off-the-shelf solutions. The three demonstrators target low to medium manufacturing volumes of complex products and they have been developed in collaboration with industrial partners within the aerospace industry. The conclusions drawn from the development of the demonstrators are that it is technically feasible to use off-the-shelf solutions in the three cases while adhering to the high quality standards of the industry. Furthermore three groups of aspects, quality aspects, product aspects and system aspects, which affect the ability to use off-the-shelf solutions for automated composite manufacturing, are identified.

    Keyword
    composite manufacturing, automation, off-the-shelf, aerospace
    National Category
    Production Engineering, Human Work Science and Ergonomics
    Identifiers
    urn:nbn:se:liu:diva-120300 (URN)
    Conference
    ICCM20 - The 20th International Conference on Composite Materials, 19-24th July 2015, Copenhagen Denmark
    Available from: 2015-07-27 Created: 2015-07-27 Last updated: 2017-05-17
    4. Low-cost Automation for Prepreg Handling - Two Cases from the Aerospace Industry
    Open this publication in new window or tab >>Low-cost Automation for Prepreg Handling - Two Cases from the Aerospace Industry
    2016 (English)In: SAE International Journal of Materials and Manufacturing, ISSN 1946-3979 (print), 1946-3987 (online), Vol. 9, no 1Article in journal (Refereed) In press
    Abstract [en]

    With an increased use of composite materials within the aerospace industry follows a need for rational and cost-effective methods forcomposite manufacturing. Manual operations are still common for low to medium manufacturing volumes and complex products.Manual operations can for example be found in material handling, when picking prepreg plies from a cutter table and stacking them toform a plane laminate in preparation for a subsequent forming operation. Stacking operations of this kind often involves a greatnumber of different ply geometries and removal of backing paper and other protecting materials like plastic. In this paper two differentdemonstrator cells for automated picking of prepreg plies and stacking of plane laminates are presented. One demonstrator is utilizinga standard industrial robot and an advanced end-effector to handle the ply variants. The other demonstrator is using a dual arm robotwhich allow for simpler end-effector design. In combination with a previously developed system for automated removal of backingpapers both systems have shown to be capable of automatically picking prepreg plies from a plane surface and stack them to generate aflat multistack laminate. The dual arm approach has shown advantageous since it result in simpler end-effector design and a successivelay down sequence that result in good adhesion between the plies in the laminate.

    Place, publisher, year, edition, pages
    Warrendale, USA: SAE International, 2016
    Keyword
    Composite, Manufacturing, Automation, Low-cost, Prepreg
    National Category
    Production Engineering, Human Work Science and Ergonomics
    Identifiers
    urn:nbn:se:liu:diva-121602 (URN)10.4271/2015-01-2606 (DOI)
    Available from: 2015-09-28 Created: 2015-09-28 Last updated: 2017-05-17Bibliographically approved
    5. Robot-Forming of Prepreg Stacks ‐ Development of Equipment and Methods
    Open this publication in new window or tab >>Robot-Forming of Prepreg Stacks ‐ Development of Equipment and Methods
    Show others...
    2016 (English)In: Proceedings of the 17th European Conference on Composite Materials (ECCM17), 2016Conference paper (Other academic)
    Abstract [en]

    Within the aerospace industry the manufacturing of composite components with complex shapes, such as spars, ribs and beams are often manufactured using manual layup and forming of prepreg material. Automated processes for prepreg layup and efficient forming techniques like vacuum forming are sometimes difficult to employ to these type of products due to technical limitations. This paper describes the development of tools and the forming sequence needed to automate sequential forming of a complex shape using an industrial robot. Plane prepreg stacks are formed to the final shape using a dual-arm industrial robot equipped with rolling tools. Tests show that the developed tools and the employed sequence can be used to form stacks to the desired shape with acceptable quality.

    National Category
    Production Engineering, Human Work Science and Ergonomics
    Identifiers
    urn:nbn:se:liu:diva-129925 (URN)
    Conference
    ECCM17 - 17th European Conference on Composite Materials 26-30th June 2016, Munich, Germany
    Available from: 2016-07-01 Created: 2016-07-01 Last updated: 2017-05-17Bibliographically approved
  • Public defence: 2017-06-09 10:15 TEMCAS, hus T, Linköping
    Genero, Magalí Martí
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Microbial Communities in Boreal Peatlands: Responses to Climate Change and Atmospheric Nitrogen and Sulfur Depositions2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Peatlands play a substantial role in regulating the global carbon balance and concentrations of the greenhouse gases CO2 and CH4 in the atmosphere, and are thus of utmost importance from a climate change perspective. Any changes of peatland functions due to natural or anthropogenic perturbations may result in changes in these ecosystem services. Soil microbial communities are essential drivers of biogeochemical processes, including the carbon cycle. In order to fully understand the effect of environmental perturbations on peatland functions, it is essential to understand how microbial communities are affected. The aim of the research presented in this thesis was to investigate the responses of the peat microbial communities to climate change and increased precipitation of nitrogen(N) and sulfur (S) compounds. High-throughput sequencing approaches were used to investigate the taxonomic and functional composition of microbial communities, and quantitative PCR was used to specifically target the methanogen community. Two field studies including three ombrotrophic peatlands each that differed in climatological conditions and atmospheric N and S depositions, were used to investigate and compare the effect of large- and local-scale environmental conditions on microbial communities. The results show that the variation in geo-climatological (temperature and precipitation) and atmospheric deposition conditions along the latitudinal gradient modulate the peat microbial community composition and the abundance of active methanogens to a greater extent thansite-related microhabitats. Furthermore, a tight coupling between the plant community composition of a site and the composition of its microbial community was observed, and was found to be mainly driven by plants rather than microorganisms. These co-occurrence networks are strongly affected by seasonal climate variability and the interactions between species in colder areas are more sensitive to climate change. The long-term effects of warming and increased N and S depositions on the peat microbial communities were further investigated using an 18-year in-situ peatland experiment simulating these perturbations. The impacts of each of these perturbations on the microbial community were found to either multiply or counteract one another, with enhanced N deposition being the most important factor. While the long-term perturbations resulted in a substantial shift in the taxonomic composition of microbial communities, only minor changes occurred in genome-encoded functional traits, indicating a functional redundancy. This could act as a buffer maintaining ecosystem functioning when challenged by multiple stressors, and could limit future changes in greenhouse gases and carbonexchange.

    List of papers
    1. Nitrogen and methanogen community composition within and among three Sphagnum dominated peatlands in Scandinavia
    Open this publication in new window or tab >>Nitrogen and methanogen community composition within and among three Sphagnum dominated peatlands in Scandinavia
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    2015 (English)In: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 81, 204-211 p.Article in journal (Refereed) Published
    Abstract [en]

    Ombrotrophic raised bogs are nutrient poor acidic peatlands accumulating organic matter. They are widely spread on northern latitudes and are substantial sources of methane emissions to the atmosphere being of great concern from a climate change perspective. We investigated the methanogen community composition along microtopographic gradients within three bogs in Scandinavia, receiving different amounts of nitrogen precipitation. Methanogenic community analyses by terminal restriction fragment length polymorphism of the mcrA gene showed different profiles among the three sites, while no in- fluence of the microtopographic gradients was observed. Peat temperature and dissolved organic carbon were the major edaphic variables explaining 38% of the variation of the methanogenic community di- versity among the bogs. The family Methanoregulaceae (hydrogenotrophic methanogens) showed the largest relative proportion and highest activity in all three sites. Quantitative PCR of the mcrA gene and transcripts showed that the most northern site, receiving the lowest atmospheric nitrogen load, had significantly lower abundance and activity of methanogens (4.7 106 and 2.4 104 mcrA copies per gram of soil, respectively), compared to the most southern site (8.2 107 and 4.6 105 mcrA copies per gram of soil, respectively), receiving the highest nitrogen load. No patterns of the mcrA gene and tran- script abundances were observed along the microtopography. The results indicated that the difference in occurrence of methanogens is mainly due to geoclimatological conditions rather than site intrinsic microtopographic variation. The study further suggests that environmental changes on the site intrinsic topography will not affect the methanogenic activity, while increasing average temperatures in Scan- dinavian ombrotrophic raised bogs might contribute to an increase of the methanogenic archaeal activity resulting in an increase of methane production. 

    Place, publisher, year, edition, pages
    Elsevier, 2015
    Keyword
    Methanogenic arhcaea, mcrA gene, peatland, microtopography, T-RFLP, qPCR
    National Category
    Ecology Microbiology Environmental Sciences
    Identifiers
    urn:nbn:se:liu:diva-113846 (URN)10.1016/j.soilbio.2014.11.016 (DOI)000350524700024 ()
    Available from: 2015-02-02 Created: 2015-02-02 Last updated: 2017-05-17Bibliographically approved
  • Björneld, Olle
    Linköping University, Department of Biomedical Engineering.
    Optisk instrument för Laparoskopisk Kärldetektion1996Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Rapporten behandlar utvecklingen och konstruktionen av ett laparoskopiskt blodkärlsidentifierande instrument. Identifiering sker med hjälp av fotopletysmografi. Fotopletysmografi betyder ungefär "detektion av volymförändrings med hjälp av ljus". Laparoskopi kan översättas med titthålskirurgi. Laparoskopioperationer sker med små runda instrument som förs in i kroppen. Rapporten diskuterar olika probmodeller, det vill säga hur sensorn skall konstrueras för att erhålla en bra mätsignal. Konkurrerande tekniker och framtida applikationer redovisas på flera ställen i rapporten. Vid mätningar på blodmodell studerades och analyserades signalkvaliten. Till slut skall tilläggas att proben fungerade tillfredsställande. Proben kunde detektera pulsationer i blodmodellen.

  • Public defence: 2017-06-09 13:00 Berzeliussalen, Linköping
    Aljabery, Firas
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Staging and tumor biological mechanisms of lymph node metastasis in invasive urinary bladder cancer2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Aim: To study the possibility of detecting lymph node metastasis in locally advanced urinary bladder cancer (UBC) treated with radical cystectomy (RC) by using preoperative positron emission tomography/computed tomography (PET/CT) and peroperative sentinel node biopsy (SNB) technique. We also investigate the clinical significance of macrophage traits expression by cancer cells, M2-macrophage infiltration (MI) in tumor stroma and the immunohistochemical expression of biomarkers in cancer cells in relation to clinicopathologic data.

    Patients and Methods: We studied prospectively 122 patients with UBC, pathological stage pT1–pT4 treated with RC and pelvic lymph node dissection (PLND) during 2005–2011 at the Department of Urology, Linköping University Hospital. In the first study, we compared the results of preoperative PET/CT and conventional CT with the findings of postoperative histopathological evaluation of lymph nodes (LNs). In the second study we investigated the value of SNB technique for detecting pathological LNs during RC in patients with UBC. W also examined the significance of the primary tumor location in the bladder in predicting the site of LN metastases, and the prognostic significance of lympho-vascular invasion (LVI) and lymph node metastasis density (LNMD) on survival. In the third study, we investigate the clinical significance of macrophage infiltration (MI) in tumor stroma and macrophage-traits expression by tumor cells. In the fourth study, we investigate the cell cycle suppression proteins p53, p21, pRb, p16, p14 ARF as well as tumors proliferative protein Ki67 and DNA repair protein ERCC1 expression in cancer cells. The results were compared with clinical and pathological characteristics and outcome.

    Results: Prior to RC, PET/CT was used to detect LN metastasis in 54 patients. PET/CT had 41% sensitivity, 86% specificity, 58% PPV, and 76% NPV, whereas the corresponding figures for conventional CT were 41%, 89%, 64%, and 77%. SNB was performed during RC in 103 patients. A median number of 29 (range 7–68) nodes per patient were examined. SNs were detected in 83 out of 103 patients (81%). The sensitivity and specificity for detecting metastatic disease by SNB varied among LN stations, with average values of 67% -90%. LNMD or ≥8% and LVI were significantly related to shorter survival. In 103 patients, MI was high in 33% of cases, while moderate and low infiltration occurred in 42% and 25% of tumors respectively. Patients with tumors containing high and moderate compared to low MI had low rate of LN metastases (P=0.06) and improved survival (P=0.06), although not at significant level. The expression of different tumor suppression proteins was altered in 47-91% of the patients. There were no significant association between cancer specific survival (CSS) and any of the studied biomarkers. In case of altered p14ARF, ERCC1 or p21, CSS was low in case of low p53 immunostaining but increased in case of p53 accumulation, although not at a significant level, indicating a possible protective effect of p53 accumulation in these cases.

    Conclusion: PET/ CT provided no improvement over conventional CT in detection and localization of regional LN metastases in bladder cancer. It is possible to detect the SN but the technique is not a reliable for perioperative localization of LN metastases; however, LVI and LNMD at a cut-off level of 8% had significant prognostic values. MI in the tumor microenvironment but not CD163 expression in tumor cells seems to be synergistic with the immune response against urinary bladder cancer. Our results further indicate that altered p53 might have protective effect on survival in case of altered p14ARF, p21, or ERCC1 indicating an interaction between these biomarkers.

    List of papers
    1. PET/CT versus conventional CT for detection of lymph node metastases in patients with locally advanced bladder cancer.
    Open this publication in new window or tab >>PET/CT versus conventional CT for detection of lymph node metastases in patients with locally advanced bladder cancer.
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    2015 (English)In: BMC urology, ISSN 1471-2490, Vol. 15, no 1, 87- p.Article in journal (Refereed) Published
    Abstract [en]

    BACKGROUND: We studied patients treated with radical cystectomy for locally advanced bladder cancer to compare the results of both preoperative positron emission tomography/computed tomography (PET/CT) and conventional CT with the findings of postoperative histopathological evaluation of lymph nodes.

    METHODS: Patients who had bladder cancer and were candidates for cystectomy underwent preoperative PET/CT using 18-fluorodeoxyglucose (FDG) and conventional CT. The results regarding lymph node involvement were independently evaluated by two experienced radiologists and were subsequently compared with histopathology results, the latter of which were reassessed by an experienced uropathologist (HO).

    RESULTS: There were 54 evaluable patients (mean age 68 years, 47 [85 %] males and 7 [15 %] females) with pT and pN status as follows: < pT2-14 (26 %), pT2-10 (18 %), and > pT2-30 (56 %); pN0 37 (69 %) and pN+ 17 (31 %). PET/CT showed positive lymph nodes in 12 patients (22 %), and 7 of those cases were confirmed by histopathology; the corresponding results for conventional CT were 11 (20 %) and 7 patients (13 %), respectively. PET/CT had 41 % sensitivity, 86 % specificity, 58 % PPV, and 76 % NPV, whereas the corresponding figures for conventional CT were 41 %, 89 %, 64 %, and 77 %. Additional analyses of the right and left side of the body or in specified anatomical regions gave similar results.

    CONCLUSIONS: In this study, PET/CT and conventional CT had similar low sensitivity in detecting and localizing regional lymph node metastasis in bladder cancer.

    National Category
    Urology and Nephrology Cancer and Oncology
    Identifiers
    urn:nbn:se:liu:diva-120796 (URN)10.1186/s12894-015-0080-z (DOI)000359832000001 ()26294219 (PubMedID)
    Available from: 2015-08-25 Created: 2015-08-25 Last updated: 2017-05-17
    2. Radio-guided sentinel lymph node detection and lymph node mapping in invasive urinary bladder cancer: a prospective clinical study.
    Open this publication in new window or tab >>Radio-guided sentinel lymph node detection and lymph node mapping in invasive urinary bladder cancer: a prospective clinical study.
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    2016 (English)In: BJU International, ISSN 1464-4096, E-ISSN 1464-410XArticle in journal (Refereed) Epub ahead of print
    Abstract [en]

    OBJECTIVES: To investigate the possibility of detecting sentinel lymph nodes (SNs) in patients with urinary bladder cancer (BCa) intra-operatively and whether the histopathological status of the identified SNs reflected that of the lymphatic field.

    PATIENTS AND METHODS: We studied 103 patients with BCa pathological stage T1-T4 who were treated with cystectomy and pelvic lymph node (LN) dissection during 2005-2011 at the Department of Urology, Linköping University Hospital. Radioactive tracer Nanocoll 70 MBq and blue dye were injected into the bladder wall around the primary tumour before surgery. SNs were detected ex vivo during the operation with a handheld Geiger probe (Gamma Detection System; Neoprobe Corp., Dublin, OH, USA). All LNs were formalin-fixed, sectioned three times, mounted on slides and stained with haematoxylin and eosin. An experienced uropathologist evaluated the slides.

    RESULTS: The mean age of the patients was 69 years, and 80 (77%) were male. Pathological staging was T1-12 (12%), T2-20 (19%), T3-48 (47%) and T4-23 (22%). A mean (range) number of 31 (7-68) nodes per patient were examined, totalling 3 253 nodes. LN metastases were found in 41 patients (40%). SNs were detected in 83 of the 103 patients (80%). Sensitivity and specificity for detecting metastatic disease by SN biopsy (SNB) varied between LN stations, with average values of 67% and 90%, respectively. LN metastatic density (LNMD) had a significant prognostic impact; a value of ≥8% was significantly related to shorter survival. Lymphovascular invasion (LVI) occurred in 65% of patients (n = 67) and was significantly associated with shorter cancer-specific survival (P < 0.001).

    CONCLUSION: We conclude that SNB is not a reliable technique for peri-operative localization of LN metastases during cystectomy for BCa; however, LNMD has a significant prognostic value in BCa and may be useful in the clinical context and in BCa oncological and surgical research. LVI was also found to be a prognostic factor.

    Place, publisher, year, edition, pages
    Wiley-Blackwell Publishing Inc., 2016
    Keyword
    #BladderCancer, #blcsm, cystectomy, lymph node metastasis, prognostic factors, sentinel node
    National Category
    Surgery
    Identifiers
    urn:nbn:se:liu:diva-136947 (URN)10.1111/bju.13700 (DOI)27797436 (PubMedID)
    Available from: 2017-05-01 Created: 2017-05-01 Last updated: 2017-05-17
  • Public defence: 2017-06-14 10:00 ACAS, A-huset, Linköping
    Aid, Graham
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Operationalizing Industrial Ecology in the Waste Sector: Roles and tactics for circular value innovation2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The take-make-waste approach to resource management in human production and consumption systems is contributing to a variety of environmental and social problems worldwide. Additionally, as the world’s population and affluence increase, so do the negative impacts of poor resource management. Lifting the waste management (WM) sector into a new phase of development, which takes its lead from the ideals of Industrial Ecology and circular economy, is seen by many scholars and practitioners as one potential to assist in alleviating these impacts. While there are many studies on how more efficient inter-organizational resource management is (or could be) constructed, there are relatively few business development studies which have explored novel approaches (from roles to tactics) that WM organizations might operationalize toward more efficient resource management.

    The aim of this thesis is to contribute to the development of knowledge and understanding of how the waste management sector can operationalize more effective and efficient resource management. In approaching this aim, two research questions guided the exploration of: 1) novel roles for WM and 2) support tactics for such roles. Grounded in the broader context of Industrial Ecology (IE) and Business Development, five studies were performed. Two studies, focused on the novel roles of inter-organizational resource management and high value secondary resource extraction, were performed through literature review and interviews, and market driver analysis respectively. In exploring support tactics, two design and proof of concept studies were carried out to investigate data analysis tools for inter-organizational resource management, and one long-term action research engagement project was coordinated to study hands-on inter-organizational collaboration tactics.

    The studies highlighted that the Swedish WM sector holds some key capacities for operationalizing (and in some cases, is already developing) the novel resource management roles identified: industrial symbiosis facilitator, eco-industrial park manager, holistic facility management, and high value resource extractor. However, depending on the portfolio of services to be performed in such roles, several capacities may need to be developed or strengthened. Main opportunities seen for these roles were – staying ahead of market developments, and aligning activities with organizational goals. The main general risk related to these roles was insufficient returns on investment. Looking forward, the main enablers identified were policy leadership for more balanced market mechanisms, increasing use of external knowledge, developing long term partnerships, lobbying, stockpiling resources, and carefully crafting new business models.

    The tools developed for strategically applying external information toward the identification of opportunities within new roles showed tactical potential. However, their implementation in broader development processes has yet to be fully validated. The hands-on exploration of change oriented collaboration, highlighted collective system framing and goal setting and face-to-face interaction as key activities for inter-organizational approaches within roles such as industrial symbiosis facilitator.

    Throughout the studies, several novel roles were investigated. Each of these roles will need to be individually evaluated by directing bodies of WM organizations, and evaluated from the organization’s vision and strategy. If certain roles are chosen to be explored in more detail, they will need to be developed within full business models - addressing issues such as income structure, internal processes and capacities to be developed, and key customers. Through applying IE and business development concepts and findings, WM organizations have possibilities to translate ambitious visions into novel offerings.

    List of papers
    1. Expanding roles for the Swedish waste management sector in interorganizational resource management
    Open this publication in new window or tab >>Expanding roles for the Swedish waste management sector in interorganizational resource management
    2017 (English)In: Resources, Conservation and Recycling, ISSN 0921-3449, E-ISSN 1879-0658, Vol. 124, 85-97 p.Article in journal (Refereed) Published
    Abstract [en]

    Several waste management (WM) professionals see an ongoing shift in the focus of the industry, from that of atransport and treatment sector to that of a more integrated sustainable service provision and material productionsector. To further develop such transitional ambitions, WM organizations are increasingly looking toward interorganizationalresource network concepts (such as the circular economy and industrial symbiosis) as models ofhow they would like to create new value together with their customers and partners.This article aims to take a step in addressing uncertainties behind such transitions by analyzing barriers forinter-organizational resource management and in turn uncovering some potential opportunities and risks ofnovel offerings from the WM sector. Obstacles for developing innovative inter-organizational resource networkshave been identified based on studies of implementing industrial symbiosis networks. Subsequently, managingexecutives from Swedish private and public WM organizations were interviewed regarding the sector’s capacityto overcome such barriers – opportunities and risks of providing new resource management services – and howtheir organizations might approach the role of actively facilitating more resource efficient regions.Eco-Industrial park management and contracting out holistic resource management are some areas in whichthe respondents see WM organizations offering new services. In relation to such approaches, various risks (e.g.being cut out of investment benefits, or unstable supply) and opportunities (e.g. new markets and enhancedsustainability profiles) were identified. Additionally, it was seen that WM companies would need to makesubstantial changes to their business approach, becoming less dependent on flows of mixed materials forexample, if they are to become even more central value chain actors. To strengthen such approaches, it was seenthat the sector will need to find methods to strategically build strong, long term partnerships, expand upon andtake advantage of available knowledge resources (i.e. best practice technologies and regional material flows),and explore new business models (i.e. stockpiling, park management, or waste minimization). Additionally,working with sector representatives to argue for a more balanced market conditions next to primary productionshould assist the viability of new offerings in the wider market.

    Keyword
    Circular economy, Industrial symbiosis, Recycling, Business development, Green innovation
    National Category
    Environmental Management
    Identifiers
    urn:nbn:se:liu:diva-137456 (URN)10.1016/j.resconrec.2017.04.007 (DOI)
    Available from: 2017-05-16 Created: 2017-05-16 Last updated: 2017-05-23
    2. Driving Forces and Inhibitors of Secondary Stock Extraction
    Open this publication in new window or tab >>Driving Forces and Inhibitors of Secondary Stock Extraction
    2016 (English)In: The Open Waste Management Journal, ISSN 1876-4002, E-ISSN 1876-4002, Vol. 9, 11-18 p.Article in journal (Refereed) Published
    Abstract [en]

    Even though it’s well known that our common resources are limited and that recycling is key for a sustainable future; inreality we see few examples of true recycling where virgin raw material is substituted by waste. There are endless numbers ofexamples where waste is utilized to some extent without solving the core issue: reducing the need of extracting virgin raw materials.This article analyses some of the driving forces and inhibitors of secondary stock extraction to explore why it’s so difficult establishlarge scale secondary stock extraction although suitable technologies are available. The authors discuss and suggest possible ways forreducing some of the main barriers presented.

    Keyword
    Circular economy, Economy, Recycling, Resources, Sustainability
    National Category
    Environmental Management
    Identifiers
    urn:nbn:se:liu:diva-137459 (URN)10.2174/1876400201609010011 (DOI)
    Available from: 2017-05-16 Created: 2017-05-16 Last updated: 2017-05-23
    3. Looplocal - a heuristic visualization tool to support the strategic facilitation of industrial symbiosis
    Open this publication in new window or tab >>Looplocal - a heuristic visualization tool to support the strategic facilitation of industrial symbiosis
    2015 (English)In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 98, 328-335 p.Article in journal (Refereed) Published
    Abstract [en]

    Industrial symbiosis (IS) developments have been differentiated as self-organized, facilitated, and planned. This article introduces a tool, Looplocal, which has been built with objectives to support the strategic facilitation of IS. Looplocal is a visualization tool built to assist in 1) Simplifying the identification of regions susceptible to new industrial symbiosis facilitation activities 2) Enabling proactive and targeted marketing of potential exchanges to key actors in specific regions and 3) Assisting facilitators to assess the various strategies and consequential engagement and analysis methodologies suitable for additional IS development in specific regions. The tool compares industrial symbiosis data and estimated regional material and energy flows (on a facility level) to identify potential IS transfer information along with key stakeholder and network data. The authors have performed a proof of concept run of this tool on Sweden. In its early stages of application the method has given results seen as useful for identifying regions susceptible to the investment of symbiosis facilitators' time and resources. The material focus and customization possibilities for the tool show potential for a spectrum of potential facilitators: from waste management companies to national or regional authorities. In conjunction with long term business models, such a tool might be utilized throughout an adaptive chain of facilitation activities and aims.

    Place, publisher, year, edition, pages
    Elsevier, 2015
    National Category
    Civil Engineering
    Identifiers
    urn:nbn:se:liu:diva-137462 (URN)10.1016/j.jclepro.2014.08.012 (DOI)000356194300033 ()2-s2.0-84929966422 (ScopusID)
    Note

    QC 20150713

    Available from: 2015-07-13 Created: 2017-05-16 Last updated: 2017-05-16Bibliographically approved
    4. Improvement of aggregate cycles in Stockholm and the Baltic Region: Activities and results of the BRA initiative
    Open this publication in new window or tab >>Improvement of aggregate cycles in Stockholm and the Baltic Region: Activities and results of the BRA initiative
    2012 (English)In: Proceedings of the 8th International conference on Sustainable management of waste and recycled materials in construction, Gothenburg, Sweden, 30 May - 1 June 2012 / [ed] M. Arm, C. Vandecasteele, J. Heynen, P. Suer and B. Lind, Swedish Geotechnical Institute , 2012, 1-9 p.Conference paper (Refereed)
    Abstract [en]

    From 2009 until 2011 project BRA (Bygg-och Rivningsavfall i Stockholms Län) “Construction and Demolition (C&D) waste in Stockholm County” was coordinated from the division of Industrial Ecology, KTH. This project was focused on actively improving (from plural perspectives) the cycles of C&D (specifically non-metallic inert) materials in the region. In response to the normative aim and inter-systems complexity, a highly participative action research procedure was adopted. Through processes of network communication, workshops, a course, and an international symposium - a number of issues (such as market development, recycled product quality, greenhouse gas impacts, collaborative planning, and statistics) were prioritized, researched, and acted upon. Indicators for measuring progress in selected areas were developed and preliminary action plans created. At a final co-organized symposium Swedish delegates laid the groundwork for the establishment of a Swedish C&D recycling b ranch organization. This initiative of continued collaboration between and within sectors is seen as a vehicle for the priorities and action requirements identified in BRA to be further enabled and held in focus. Furthermore, these actors taking ownership of the process is seen as a success in accordance to the original aims and the need for further cycles of evaluation, planning, and action.

    Place, publisher, year, edition, pages
    Swedish Geotechnical Institute, 2012
    Keyword
    by-product, recycling, synergy, industrial ecology, facilitation
    National Category
    Construction Management
    Identifiers
    urn:nbn:se:liu:diva-137463 (URN)
    Conference
    WASCON 2012 – towards effective, durable and sustainable production and use of alternative materials in construction. 8th International conference on sustainable management of waste and recycled materials in construction, Gothenburg, Sweden, 30 May - 1 June 2012
    Note

    QC 20130522

    Available from: 2013-05-20 Created: 2017-05-16 Last updated: 2017-05-16Bibliographically approved
  • Public defence: 2017-06-16 13:00 K2, Kåkenhus, Norrköping
    Machat-From, Laura
    Linköping University, Department of Social and Welfare Studies, Division Ageing and Social Change. Linköping University, Faculty of Arts and Sciences.
    Identity, Old(er) Age and Migrancy: A Social Constructionist Lens2017Doctoral thesis, monograph (Other academic)
    Abstract [en]

    ldentity research in relation to ethnicity and migration has tended to focus an younger people whilst identity research in relation to ageing and old(er) age has not focused an migrants. This inadvertent mutual neglect has led to a lack of identity research that examines the identity categories of old(er) age and migrancy together, a lacuna that this dissertation aims to redress. This dissertation departs from a social constructionist understanding of identity as situationally accomplished in the interplay between how one defines oneself (internally) and how others define one (externally). The questions raised by this perspective and addressed in this dissertation are: When (in what situations) and in relation to whom do old(er) age and migrancy (respectively) seem to become meaningful for identification? How do the identity categories of old(er) age and migrancy seem to be negotiated? The empirical material consists of in-depth interviews with 24 older migrants (13 men, 11 women) aged between 55 and 79 who have been living in Sweden for 18 to 61 years. Interviewees come from 12 different countries that vary in perceived cultural distance from Sweden. The findings suggest that identifications with old(er) age and migrancy seem to be dynamic and flexible rather than necessarily permanently meaningful, thus gaining meaning in specific situations and in relation to particular Others. External definitions furthermore do not always seem to match with internal ones. Regardless of how old(er) age and migrancy are constructed, they seem to be negotiable. This dissertation thus contributes to identity research by studying old(er) age and migrancy together and furthermore sheds light onto how the social constructionist lens allows us to see variability where stability otherwise would be presumed.

  • Olsson, Magdalena
    Linköping University, Department of Management and Engineering, Commercial and Business Law.
    Betydelsen av att den försäkrade orsakat skada genom ett oaktsamt agerande: En studie i de varierande aktsamhetskrav som gäller för olika slags egendomsförsäkringar2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Försäkringstagarens aktsamhetskrav skiljer sig för olika slags egendomsförsäkringar där försäkringsvillkor för brand, vattenutströmning, inbrott samt rån har studerats i denna framställning. Aktsamhetskraven kan exempelvis ge uttryck för hur en anställd i ett företag ska agera eller hur försiktig denne bör vara för att försärsäkringsersättning ska utgå vid en inträffad skada. Försäkringsbolagen har stora möjligheter att utforma villkoren och därmed välja hur höga krav det ska ställas på den försäkrade. Bolagen kan även välja att lägga över bevisbördan på försäkringstagaren för att ett försäkringsfall har inträffat samt reglera vilka personer i ett företag som ska likställas med den försäkrade.

    Det finns även biförpliktelser i FAL som försäkringstagaren ska ta hänsyn till för att inte riskera att försäkringsersättningen sätts ned eller uteblir helt. Efter nya FAL infördes bland annat den så kallade omfattningsbestämmelsen i 8 kap. 16 § 2 st. FAL. Bestämmelsen tillåter som huvudregel inte att försäkringsbolagen får ställa krav på den försäkrades beteende i villkor som beskriver försäkringens omfattning. Ett omdiskuterat begrepp som framför allt förekommer i allriskförsäkringen, och som uppställs som ett omfattningsvillkor, är oförutsedd skada. Att försäkringstagarens aktsamhet har betydelse för att avgöra om en skada varit oförutsedd, är inte förenligt med gällande rätt. Dessutom kan kravet till stor del jämföras med FAL:s uppställda förpliktelse att inte framkalla ett försäkringsfall, vilket medför att ett sådant krav kan ses som obefogat.

    Det finns även andra tvivelaktiga formuleringar i försäkringsvillkoren. Tillämpningen av omfattningsbestämmelsen är i stort behov av att tydliggöras, för att inte riskera att det ställs oskäliga krav på försäkringstagaren i förhållande till egendomsförsäkringens ändamål. Det är inte rimligt om försäkringsskyddet hade uteslutit alla skador som grundar sig i någon form av oaktsamhet hos den försäkrade. Ett skäl till att ett företag väljer att teckna en försäkring är för att tillåtas att göra misstag, utan att det föranleder att försäkringsbolaget står fritt från ansvar.

  • Public defence: 2017-06-17 10:15 Planck, Fysikhuset, Linköping
    Bergkvist, Liza
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Amyloid-β and lysozyme proteotoxicity in Drosophila: Beneficial effects of lysozyme and serum amyloid P component in models of Alzheimer’s disease and lysozyme amyloidosis2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the work presented this thesis, two different conditions that are classified as protein misfolding diseases: Alzheimer's disease and lysozyme amyloidosis and proteins that could have a beneficial effect in these diseases, have been studied using Drosophila melanogaster, commonly known as the fruit fly. The fruit fly has been used for over 100 years to study and better understand fundamental biological processes. Although the fruit fly, unlike humans, is an invertebrate, many of its central biological mechanisms are very similar to ours. The first transgenic flies were designed in the early 1980s, and since then, the fruit fly has been one of the most widely used model organisms in studies on the effects of over-expressed human proteins in a biological system; one can regard the fly as a living, biological test tube. For  most proteins, it is necessary that they fold into a three-dimensional structure to function properly. But sometimes the folding goes wrong; this may be due to mutations that make the protein unstable and subject to misfolding. A misfolded protein molecule can then aggregate with other misfolded proteins. In Alzheimer's disease, which is the most common form of dementia, protein aggregates are present in the brains of patients. These aggregates are composed of the amyloid-β (Aβ) peptide, a small peptide of around 42 amino acids which is cleaved from the larger, membrane-bound, protein AβPP by two different enzymes, BACE1 and γ-secretase. In the first part of this thesis, two different fly models for Alzheimer’s disease were used: the Aβ fly model, which directly expresses the Aβ peptide, and the AβPP-BACE1 fly model, in which all the components necessary to produce the Aβ peptide in the fly are expressed in the fly central nervous system (CNS). The two different fly models were compared and the results show that a significantly smaller amount of the Aβ peptide is needed to achieve the same, or an even greater, toxic effect in the AβPP-BACE1 model compared to the Aβ model. In the second part of the thesis, these two fly models for Alzheimer’s disease were again used, but now to investigate whether lysozyme, a protein involved in our innate immune system, can counteract the toxic effect of Aβ generated in the fly models. And indeed, lysozyme is able to save the flies from Aβ-induced toxicity. Aβ and lysozyme were found to interact with each other in vivo. The second misfolding disease studied in this thesis is lysozyme amyloidosis. It is a rare, dominantly inherited amyloid disease in which mutant variants of lysozyme give rise to aggregates, weighing up to several kilograms, that accumulate around the kidneys and liver, eventually leading to organ failure. In the third part of this thesis, a fly model for lysozyme amyloidosis was used to study the effect of co-expressing the serum amyloid P component (SAP), a protein that is part of all protein aggregates found within this disease class. SAP is able to rescue the toxicity induced by expressing the mutant variant of lysozyme, F57I, in the fly's CNS. To further investigate how SAP was able to do this, double-expressing lysozyme flies, which exhibit stronger disease phenotypes than those of the single-expressing lysozyme flies previously studied, were used in the fourth part of this thesis. SAP was observed to reduce F57I toxicity and promote F57I to form aggregates with more distinct amyloid characteristics. In conclusion, the work included in this thesis demonstrates that: i) Aβ generated from AβPP processing in the fly CNS results in higher proteotoxicity compared with direct expression of Aβ from the transgene, ii) lysozyme can prevent Aβ proteotoxicity in Drosophila and could thus be a potential therapeutic molecule to treat Alzheimer’s disease and iii) in a Drosophila model of lysozyme amyloidosis, SAP can prevent toxicity from the disease-associated lysozyme variant F57I and promote formation of aggregated lysozyme morphotypes with amyloid properties; this is important to take into account when a reduced level of SAP is considered as a treatment strategy for lysozyme amyloidosis.

    List of papers
    1. A beta PP processing results in greater toxicity per amount of A beta(1-42) than individually expressed and secreted A beta(1-42) in Drosophila melanogaster
    Open this publication in new window or tab >>A beta PP processing results in greater toxicity per amount of A beta(1-42) than individually expressed and secreted A beta(1-42) in Drosophila melanogaster
    2016 (English)In: BIOLOGY OPEN, ISSN 2046-6390, Vol. 5, no 8, 1030-1039 p.Article in journal (Refereed) Published
    Abstract [en]

    The aggregation of the amyloid-beta (A beta) peptide into fibrillar deposits has long been considered the key neuropathological hallmark of Alzheimers disease (AD). A beta peptides are generated from proteolytic processing of the transmembrane A beta precursor protein (A beta PP) via sequential proteolysis through the beta-secretase activity of beta-site A beta PP-cleaving enzyme (BACE1) and by the intramembranous enzyme gamma-secretase. For over a decade, Drosophila melanogaster has been used as a model organism to study AD, and two different approaches have been developed to investigate the toxicity caused by AD-associated gene products in vivo. In one model, the A beta peptide is directly over-expressed fused to a signal peptide, allowing secretion of the peptide into the extracellular space. In the other model, human A beta PP is co-expressed with human BACE1, resulting in production of the A beta peptide through the processing of A beta PP by BACE1 and by endogenous fly gamma-secretase. Here, we performed a parallel study of flies that expressed the A beta(1-42) peptide alone or that co-expressed A beta PP and BACE1. Toxic effects (assessed by eye phenotype, longevity and locomotor assays) and levels of the A beta(1-42), A beta(1-40) and A beta(1-38) peptides were examined. Our data reveal that the toxic effect per amount of detected A beta(1-42) peptide was higher in the flies co-expressing A beta PP and BACE1 than in the A beta(1-42)-expressing flies, and that the co-existence of A beta(1-42) and A beta(1-40) in the flies co-expressing A beta PP and BACE1 could be of significant importance to the neurotoxic effect detected in these flies. Thus, the toxicity detected in these two fly models seems to have different modes of action and is highly dependent on how and where the peptide is generated rather than on the actual level of the A beta(1-42) peptide in the flies. This is important knowledge that needs to be taken into consideration when using Drosophila models to investigate disease mechanisms or therapeutic strategies in AD research.

    Place, publisher, year, edition, pages
    COMPANY OF BIOLOGISTS LTD, 2016
    Keyword
    Alzheimers disease; Amyloid-beta (A beta); A beta PP processing; Drosophila melanogaster; Proteotoxicity
    National Category
    Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
    Identifiers
    urn:nbn:se:liu:diva-131685 (URN)10.1242/bio.017194 (DOI)000382304400003 ()27387531 (PubMedID)
    Note

    Funding Agencies|Torsten Soderbergs Stiftelse [M26/11]; Alzheimer Foundation [03-069]; Dementia Foundation; Ahlen Foundation; Gamla Tjanarinnor [2015-00187]

    Available from: 2016-10-03 Created: 2016-09-30 Last updated: 2017-05-16
    2. Beneficial effects of increased lysozyme levels in Alzheimer’s disease modelled in Drosophila melanogaster
    Open this publication in new window or tab >>Beneficial effects of increased lysozyme levels in Alzheimer’s disease modelled in Drosophila melanogaster
    Show others...
    2016 (English)In: The FEBS Journal, ISSN 1742-464X, E-ISSN 1742-4658, Vol. 283, no 19, 3508-3522 p.Article in journal (Refereed) Published
    Abstract [en]

    Genetic polymorphisms of immune genes that associate with higher risk to develop Alzheimer’s disease (AD) have led to an increased research interest on the involvement of the immune system in AD pathogenesis. A link between amyloid pathology and immune gene expression was suggested in a genome-wide gene expression study of transgenic amyloid mouse models. In this study, the gene expression of lysozyme, a major player in the innate immune system, was found to be increased in a comparable pattern as the amyloid pathology developed in transgenic mouse models of AD. A similar pattern was seen at protein levels of lysozyme in human AD brain and CSF, but this lysozyme pattern was not seen in a tau transgenic mouse model. Lysozyme was demonstrated to be beneficial for different Drosophila melanogaster models of AD. In flies that expressed Aβ1-42 or AβPP together with BACE1 in the eyes, the rough eye phenotype indicative of toxicity was completely rescued by coexpression of lysozyme. In Drosophila flies bearing the Aβ1-42 variant with the Arctic gene mutation, lysozyme increased the fly survival and decreased locomotor dysfunction dose dependently. An interaction between lysozyme and Aβ1-42 in the Drosophila eye was discovered. We propose that the increased levels of lysozyme, seen in mouse models of AD and in human AD cases, were triggered by Aβ1-42 and caused a beneficial effect by binding of lysozyme to toxic species of Aβ1-42, which prevented these from exerting their toxic effects. These results emphasize the possibility of lysozyme as biomarker and therapeutic target for AD.

    Place, publisher, year, edition, pages
    John Wiley & Sons, 2016
    Keyword
    Alzheimer’s disease, amyloid-β, Drosophila, lysozyme
    National Category
    Genetics Medical Genetics Developmental Biology Bioinformatics and Systems Biology Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
    Identifiers
    urn:nbn:se:liu:diva-131796 (URN)10.1111/febs.13830 (DOI)000386033700001 ()27562772 (PubMedID)
    Available from: 2016-10-07 Created: 2016-10-07 Last updated: 2017-05-16Bibliographically approved
    3. Serum Amyloid P Component Ameliorates Neurological Damage Caused by Expressing a Lysozyme Variant in the Central Nervous System of Drosophila melanogaster
    Open this publication in new window or tab >>Serum Amyloid P Component Ameliorates Neurological Damage Caused by Expressing a Lysozyme Variant in the Central Nervous System of Drosophila melanogaster
    2016 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 7, e0159294- p.Article in journal (Refereed) Published
    Abstract [en]

    Lysozyme amyloidosis is a hereditary disease in which mutations in the gene coding for lysozyme leads to misfolding and consequently accumulation of amyloid material. To improve understanding of the processes involved we expressed human wild type (WT) lysozyme and the disease-associated variant F57I in the central nervous system (CNS) of a Drosophila melanogaster model of lysozyme amyloidosis, with and without co-expression of serum amyloid p component (SAP). SAP is known to be a universal constituent of amyloid deposits and to associate with lysozyme fibrils. There are clear indications that SAP may play an important role in lysozyme amyloidosis, which requires further elucidation. We found that flies expressing the amyloidogenic variant F57I in the CNS have a shorter lifespan than flies expressing WT lysozyme. We also identified apoptotic cells in the brains of F57I flies demonstrating that the flies neurological functions are impaired when F57I is expressed in the nerve cells. However, co-expression of SAP in the CNS prevented cell death and restored the F57I flies lifespan. Thus, SAP has the apparent ability to protect nerve cells from damage caused by F57I. Furthermore, it was found that co-expression of SAP prevented accumulation of insoluble forms of lysozyme in both WT- and F57I-expressing flies. Our findings suggest that the F57I mutation affects the aggregation process of lysozyme resulting in the formation of cytotoxic species and that SAP is able to prevent cell death in the F57I flies by preventing accumulation of toxic F57I structures.

    Place, publisher, year, edition, pages
    PUBLIC LIBRARY SCIENCE, 2016
    National Category
    Developmental Biology
    Identifiers
    urn:nbn:se:liu:diva-131183 (URN)10.1371/journal.pone.0159294 (DOI)000380169300043 ()27428539 (PubMedID)
    Note

    Funding Agencies|Swedish Research Council; Soderberg foundation [M26/11]; Linkoping University Neurobiology Center

    Available from: 2016-09-19 Created: 2016-09-12 Last updated: 2017-05-16
  • Perselli, Viktor
    Linköping University, Department of Culture and Communication.
    Flipped Classroom im Fremdsprachenunterricht - Möglichkeiten und Herausforderungen2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Det här arbetet ger en inblick i forskningsläget gällande Flipped Classroom i främmandespråk-undervisning. Flipped Classroom är ett modernt begrepp och många lärare använder metoden även i Sverige.Flipped Classroom är, något förenklat, när elever/studenter tittar på undervisningsvideoklipp hemma och de typiska läxorna istället görs på lektionen. Målet med det här arbetet är att ta reda på om Flipped Classroom är ett koncept som passar i främmandespråkundervisningen.För att ävenvisa vilka förutsättningar som behövs vid språkinlärning,finns därför också viss språkinlärningsforskning med i arbetetsom bakgrund. Arbetet är upplagt som en systematisk litteraturstudie föratttydligt redovisa använda metoder och vara öppen för granskning. I arbetet ingår en sammanfattning av 9 funna artiklar om Flipped Classroom i främmandespråkundervisning, som har hittats genom sökningar via Unisearch, Eric och Fachportal Pädagogik. Möjligheter och utmaningar som forskarna lyfter fram i sina artiklar har kategoriserats och lyfts fram och jämförts med avsnittet med språkinlärningsforskning. Dessutom sammanställs de råd som Flipped-Classroom-forskarna lyfter fram i sina artiklar för ett eventuellt införande av konceptet i läsarens undervisning. Resultaten visar att Flipped-Classroom-konceptet erbjuder alla nödvändiga förutsättningar för språkinlärning, om både aktiviteter för lektionstid som videomaterial för användning utanför undervisningen är välgjorda. Det har också framkommit att eleverna/studenterna har visat på högre akademiska prestationer, höjd motivation och ett mer individualiserat lärande.Utmaningarna beståri en initialt höjd arbetsbelastning för lärarna, då konceptet för bästa resultat kräver egenproducerat videomaterial, samt kan innebära tekniska svårigheter vid framställningen och publiceringen av materialet. Flipped Classroom är ett omtyckt koncept för de inblandade i studierna, men både lärare och studenter/elever kan behöva en invänjningsperiod. Därförrekommenderas att införandet av Flipped Classroom görs steg för steg, inte minst för att minska på lärarens arbetsbörda.

  • Malkey, Simeli
    et al.
    Linköping University, Department of Behavioural Sciences and Learning.
    Borancic, Dzama
    Linköping University, Department of Behavioural Sciences and Learning.
    Det spelar ingen roll vilket förstaspråk du talar, jag ska lära dig ett andraspråk.: andraspråks eleven läs och skrivinlärning2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna litteraturstudie är att redogöra för hur kan läraren arbeta för att utveckla läs-och språkinlärningen för andraspråkselever.

    Litteraturstudiens resultat behandlar 12 refereegranskade artiklar med kvalitativa och kvantitativa ansatser. Resultatet besvarar studiens syfte och frågeställning. Litteraturstudiens resultat visar att tillämpning av den sociokulturella teorin (scaffolding och ZPD) är viktigt vid språkinlärning. Läraren kan bland annat tillämpa scaffolding via interaktion och kommunikation. Resultaten indikerar att fonologisk medvetenhet är väsentligt för andraspråkselevens läsinlärning. Artiklarnas resultat visade vidare att en kombination av flera strategier var gynnande vid andraspråkselevens läs- och språkinlärning. Detta genom exempelvis tillämpning av arbetsstrategierna; grupparbeten, kommunikation, repetition, högläsning, uttal-ord-bild, fonologisk medvetenhet, motivation samt metoden en läsande klass. Vissa utvalda artiklar visade även lärares utmaningar med andraspråksinlärning.

  • Public defence: 2017-06-09 10:15 ACAS, hus A, Linköping
    Liu, Linn
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    A systematic approach for major renovation of residential buildings2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In Sweden, buildings are responsible for about 40 % of total energy use and about 10 % of total CO2 emissions Today more than 60 % of existing Swedish residential buildings are over 40 years old and are in need of major renovation. In addition, 15 % of all multi-family buildings and 27 % of all single-family houses were built before 1945. The increased energy use and threat from CO2 emissions of the building sector create a need for energy efficiency. The important role that renovation of residential buildings will play in reducing the total energy used by the Swedish building sector as well as in reducing primary energy use and CO2 emissions on both the national and global levels has been the impetus for the studies included in this thesis.

    The aim of the current research is to develop a methodology from a system perspective which can be used to analyze the energy use, optimal life cycle cost (LCC), energy efficiency measure (EEM) package, indoor environment, CO2 emissions, and primary energy use of a building or a community during major renovation. The developed methodology accomplished at three different levels, i.e. building level, cluster level and district level. The methodology considers both energy efficiency and economic viability during building renovation and will also play an important role in overall urban planning. The studied buildings include both non-listed and listed residential buildings and the tools used include building energy simulation (BES), survey, technical measurements, LCC optimization and building categorization.

    The results show that the combination of BES, technical measurements and surveys provides a holistic approach for evaluation of energy use and indoor environment of the studied residential buildings. The results from the current study also show that the 2020 energy target, i.e., reduction of energy use by 20 %, for the building sector can be achieved by all the studied building types and that the total LCC of these buildings are below the cost-optimal point. In comparison, the 2050 energy target, i.e., reduction of energy use by 50 %, for the building sector may be achieved by the non-listed buildings, but when the constraints relevant to listed buildings are added the cost-optimality changes as some EEMs in direct conflict with the building’s heritage value may not be implemented.

    The investigation of primary energy use and CO2 emissions by the residential buildings show that the higher the energy saving, the lower the primary energy use becomes, and vice versa. With the same energy saving, the heating system with higher primary energy factor results in higher primary energy use. From a CO2 emissions point of view, EEM packages proposed to help buildings connected to a CHP based district heating system, to reduce the energy use or LCC are not consistently effective. Since these EEM packages will reduce district heating demand, the electricity produced in the CHP plant will also decrease. When the biomass is considered a limited resource, measures such as investment in a biofuel boiler are not favourable from the CO2 emissions point of view. The current study has also shown that combining building categorization method and LCC optimization method will help the community to reduce its energy use, primary energy use and CO2 emissions in a systematic and strategic way.

    List of papers
    1. Comprehensive investigation on energy retrofits in eleven multi-family buildings in Sweden
    Open this publication in new window or tab >>Comprehensive investigation on energy retrofits in eleven multi-family buildings in Sweden
    2014 (English)In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 84, 704-715 p.Article in journal (Refereed) Published
    Abstract [en]

    Rapidly growing energy use in the building sector is considered a serious problem by both the European Union (EU) and Sweden. Reducing energy demand in the building sector is important for Sweden in order to reach national energy goals for reduced energy use and CO2 emissions in the future. This project aims to find energy efficiency potential in multifamily buildings in the Gävleborg region, which is a cold climate region in Sweden. Measurements and simulations have been made on eleven multifamily buildings from the whole region. The results include different energy efficiency measure packages, profitability analysis of individual measures and packages, and primary energy use analysis. The paper also includes CO2 emissions reduction analysis based on different methods. The project shows that the multifamily buildings in the Gävleborg region have good potential to reduce their energy use by more than 50%, which in turn will contribute to 43% primary energy reduction and 48% CO2 emissions reduction.

    Place, publisher, year, edition, pages
    Elsevier, 2014
    National Category
    Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-111051 (URN)10.1016/j.enbuild.2014.08.044 (DOI)000345182000070 ()
    Available from: 2014-10-06 Created: 2014-10-06 Last updated: 2017-05-16Bibliographically approved
    2. Evaluating indoor environment of a retrofitted multi-family building with improved energy performance in Sweden
    Open this publication in new window or tab >>Evaluating indoor environment of a retrofitted multi-family building with improved energy performance in Sweden
    2015 (English)In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 102, 32-44 p.Article in journal (Refereed) Published
    Abstract [en]

    The building sector within both the EU and Sweden accounts for about 40% of total energy use. It is therefore important to introduce energy efficiency measures in this sector in order to meet the national implementation of the Building Performance Directive. Retrofits that result in improved energy performance are important in order to meet national energy targets, but the impact on the indoor environment has to be considered. Properly chosen energy efficiency measures may affect the indoor environment positively. One retrofitted multi-family building, located in the city of Linkoping, Sweden, was chosen as the study object. The building represents a common type of construction in Sweden. This study presents an evaluation of both the indoor environment and energy use of the retrofitted building in comparison with a similar non-retrofitted building from the same area. The results show that the building has potential to reach a 39% reduction of space heating demand. The indoor environment has been improved compared to the non-retrofitted building. Adding external blinds from 15 May to 15 September between 10am-12pm on the east side and 12pm-3pm on the west side seems to be the best option for improving the indoor climate during summer. (c) 2015 Elsevier B.V. All rights reserved.

    Place, publisher, year, edition, pages
    Elsevier, 2015
    Keyword
    Multi-family building; Retrofit; Building energy simulation; Energy use; Indoor environment
    National Category
    Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-120720 (URN)10.1016/j.enbuild.2015.05.021 (DOI)000358458100003 ()
    Note

    Funding Agencies|Swedish Energy Agency

    Available from: 2015-08-24 Created: 2015-08-24 Last updated: 2017-05-16
    3. A Method to Assess the Potential for and Consequences of Energy Retrofits in Swedish Historic Buildings
    Open this publication in new window or tab >>A Method to Assess the Potential for and Consequences of Energy Retrofits in Swedish Historic Buildings
    Show others...
    2014 (English)In: The Historic Environment: Policy & Practice, ISSN 1756-7505, E-ISSN 1756-7513, Vol. 5, no 2, 150-166 p.Article in journal (Refereed) Published
    Abstract [en]

    The Swedish research project Potential and Policies for Energy Efficiency in Swedish Historic Buildings aims to investigate the interdependency between political energy targets and effects on the built heritage. The first part of this paper presents an iterative and interactive method to assess the potential for and consequences of improving the energy performance in a stock of historic buildings. Key elements in the method are: categorisation of the building stock, identifying targets, assessment of measures, and life-cycle cost optimisation. In the second part of the paper, the method is applied to a typical Swedish building. The selected case study shows how the method allows for an interaction between the quantitative assessment of the techno-economic optimisation and the qualitative assessment of vulnerability and other risks. Through a multidisciplinary dialogue and iteration it is possible to arrive at a solution that best balances energy conservation and building conservation in a given decision context.

    Place, publisher, year, edition, pages
    Maney Publishing, 2014
    Keyword
    cultural significance; energy efficiency; heritage values; historic buildings; life-cycle cost
    National Category
    Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-109231 (URN)10.1179/1756750514Z.00000000055 (DOI)000338773000006 ()
    Available from: 2014-08-12 Created: 2014-08-11 Last updated: 2017-05-16Bibliographically approved
    4. LCC assessments and environmental impacts on the energy renovation of a multi-family building from the 1890s
    Open this publication in new window or tab >>LCC assessments and environmental impacts on the energy renovation of a multi-family building from the 1890s
    2016 (English)In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 133, 823-833 p.Article in journal (Refereed) Published
    Abstract [en]

    The 2020 and 2050 energy targets increase requirements on energy performance in the building stock, thus affecting both listed and non-listed buildings. It is important to select appropriate and cost-optimal energy efficiency measures, using e.g. Life Cycle Cost (LCC) optimization. The aim of this paper is to find cost-optimal packages of energy efficiency measures (EEMs) as well as to explore the effects of specific predesigned energy target values for a listed Swedish multi-family building from the 1890s. The purpose is also to show the effects on energy use, LCC, primary energy use and CO2 emissions of different energy targets, discount rates, electricity prices and geographic locations. The results show that separate energy targets could be an effective way to simplify the implementation for listed buildings. Furthermore, a cost-optimal package of EEMs is more sensitive to changes in discount rate than in electricity price. The energy renovation has impact on the primary energy use and CO2 emissions. The lower the discount rate is, the more EEMs will be implemented and the easier the national energy targets may be achieved. A higher electricity price also leads to more EEMs being implemented but at the same time higher running costs. (C) 2016 Elsevier B.V. All rights reserved.

    Place, publisher, year, edition, pages
    ELSEVIER SCIENCE SA, 2016
    Keyword
    LCC assessments; Environmental impacts; Energy efficiency measures package; Listed/non-listed building; Renovation; Energy targets
    National Category
    Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-133507 (URN)10.1016/j.enbuild.2016.10.040 (DOI)000389087300072 ()
    Note

    Funding Agencies|Swedish Energy Agency

    Available from: 2016-12-30 Created: 2016-12-29 Last updated: 2017-05-16
  • Stenberg, Pontus
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Danielsson, Örjan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Erdtman, Edvin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Sukkaew, Pitsiri
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ojamäe, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Matching precursor kinetics to afford a more robust CVD chemistry: a case study of the C chemistry for silicon carbide using SiF4 as Si precursor2017In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534Article in journal (Refereed)
    Abstract [en]

    Chemical Vapor Deposition (CVD) is one of the technology platforms forming the backbone of the semiconductor industry and is vital in the production of electronic devices. To upscale a CVD process from the lab to the fab, large area uniformity and high run-to-run reproducibility are needed. We show by a combination of experiments and gas phase kinetics modeling that the combinations of Si and C precursors with the most well-matched gas phase chemistry kinetics gives the largest area of of homoepitaxial growth of SiC. Comparing CH4, C2H4 and C3H8 as carbon precursors to the SiF4 silicon precursor, CH4 with the slowest kinetics renders the most robust CVD chemistry with large area epitaxial growth and low temperature sensitivity. We further show by quantum chemical modeling how the surface chemistry is impeded by the presence of F in the system which limits the amount of available surface sites for the C to adsorb.

  • Public defence: 2017-06-02 13:15 TEMCAS, TEMA-huset, Linköping
    Holm, Marie-Louise
    Linköping University, Department of Thematic Studies, The Department of Gender Studies. Linköping University, Faculty of Arts and Sciences.
    Fleshing out the self: Reimagining intersexed and trans embodied lives through (auto)biographical accounts of the past2017Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This thesis explores how current ways of imagining possibilities for intersexed and trans embodied lives within medical contexts might be informed by and reimagined through the historical lived experiences of intersexed and trans individuals as they have been articulated in autobiographical accounts.

    Postmodern, queer, intersex, and trans researchers and activists have criticised existing standards of intersex and trans healthcare for limiting the possibilities for diverse embodied lives by articulating certain forms of embodiment and selfhood as more likely to enable a liveable life than others. This has often been done in a medico-legal context by referring to experiences in the past of the unliveability of corporealities and gendersexed situations that differ from privileged positions. With a point of departure in these critiques, this thesis reopens questions about how intersexed and trans people may be embodied and have relations with others by reflecting upon the period of the first three-quarters of the 20th century, when the present standards of care and diagnostic categories were emerging, but had not yet become established.

    Drawing upon a unique set of historical source material from the archives of the Danish Ministry of Justice and the Medico-Legal Council, intersexed and trans persons’ life stories are rearticulated from their own and medico-legal experts’ accounts written in relation to applications for change of legal gendersex status and medical transition. In this way, the process is traced through which these life stories have been repeatedly rearticulated in order to become a usable basis for diagnosis and decision-making. At the same time, the stories are unfolded once more in a rearticulation focusing on their complexity and diversity.

  • Public defence: 2017-06-01 10:00 Nobel BL32, B-huset, Linköping
    Kurujyibwami, Celestin
    Linköping University, Department of Mathematics, Mathematics and Applied Mathematics. Linköping University, Faculty of Science & Engineering.
    Admissible transformations and the group classification of Schrödinger equations2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    We study admissible transformations and solve group classification problems for various classes of linear and nonlinear Schrödinger equations with an arbitrary number n of space variables.

    The aim of the thesis is twofold. The first is the construction of the new theory of uniform seminormalized classes of differential equations and its application to solving group classification problems for these classes. Point transformations connecting two equations (source and target) from the class under study may have special properties of semi-normalization. This makes the group classification of that class using the algebraic method more involved. To extend this method we introduce the new notion of uniformly semi-normalized classes. Various types of uniform semi-normalization are studied: with respect to the corresponding equivalence group, with respect to a proper subgroup of the equivalence group as well as the corresponding types of weak uniform semi-normalization. An important kind of uniform semi-normalization is given by classes of homogeneous linear differential equations, which we call uniform semi-normalization with respect to linear superposition of solutions.

    The class of linear Schrödinger equations with complex potentials is of this type and its group classification can be effectively carried out within the framework of the uniform semi-normalization. Computing the equivalence groupoid and the equivalence group of this class, we show that it is uniformly seminormalized with respect to linear superposition of solutions. This allow us to apply the version of the algebraic method for uniformly semi-normalized classes and to reduce the group classification of this class to the classification of appropriate subalgebras of its equivalence algebra. To single out the classification cases, integers that are invariant under equivalence transformations are introduced. The complete group classification of linear Schrödinger equations is carried out for the cases n = 1 and n = 2.

    The second aim is to study group classification problem for classes of generalized nonlinear Schrödinger equations which are not uniformly semi-normalized. We find their equivalence groupoids and their equivalence groups and then conclude whether these classes are normalized or not. The most appealing classes are the class of nonlinear Schrödinger equations with potentials and modular nonlinearities and the class of generalized Schrödinger equations with complex-valued and, in general, coefficients of Laplacian term. Both these classes are not normalized. The first is partitioned into an infinite number of disjoint normalized subclasses of three kinds: logarithmic nonlinearity, power nonlinearity and general modular nonlinearity. The properties of the Lie invariance algebras of equations from each subclass are studied for arbitrary space dimension n, and the complete group classification is carried out for each subclass in dimension (1+2). The second class is successively reduced into subclasses until we reach the subclass of (1+1)-dimensional linear Schrödinger equations with variable mass, which also turns out to be non-normalized. We prove that this class is mapped by a family of point transformations to the class of (1+1)-dimensional linear Schrödinger equations with unique constant mass.

    List of papers
    1. Equivalence groupoid for (1+2)-dimensional linear Schrodinger equations with complex potentials
    Open this publication in new window or tab >>Equivalence groupoid for (1+2)-dimensional linear Schrodinger equations with complex potentials
    2015 (English)In: SEVENTH INTERNATIONAL WORKSHOP: GROUP ANALYSIS OF DIFFERENTIAL EQUATIONS AND INTEGRABLE SYSTEMS (GADEISVII), IOP Publishing: Conference Series / Institute of Physics (IoP) , 2015, Vol. 621, no UNSP 012008, UNSP 012008- p.Conference paper (Refereed)
    Abstract [en]

    We describe admissible point transformations in the class of (1+2)-dimensional linear Schrodinger equations with complex potentials. We prove that any point transformation connecting two equations from this class is the composition of a linear superposition transformation of the corresponding initial equation and an equivalence transformation of the class. This shows that the class under study is semi-normalized.

    Place, publisher, year, edition, pages
    IOP Publishing: Conference Series / Institute of Physics (IoP), 2015
    Series
    Journal of Physics Conference Series, ISSN 1742-6588 ; 621
    National Category
    Mathematics
    Identifiers
    urn:nbn:se:liu:diva-120668 (URN)10.1088/1742-6596/621/1/012008 (DOI)000357939100008 ()
    Conference
    7th International Workshop on Group Analysis of Differential Equations and Integrable Systems (GADEIS)
    Available from: 2015-08-20 Created: 2015-08-20 Last updated: 2017-05-15
  • Alexandersson, Sofie
    et al.
    Linköping University, Department of Medical and Health Sciences.
    Brickarp, Louise
    Linköping University, Department of Medical and Health Sciences.
    Sjuksköterskors erfarenheter av att vårda satellitpatienter: Jakten på vårdplatser i den svenska hälso- och sjukvården.2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Background: A shortage of hospital beds prevails in Swedish hospitals at the moment. This has led to care unit overcrowdings, which so far has been solved by outlocation of patients. This study’s background presents a variety of aspects related to these patients’ care, who sometimes also are called satellite patients.

    Aim: To describe nurses’ experiences of caring for satellite patients.

    Method: An interview study with a deductive approach has been conducted. Data was collected by semi-structured interviews with eight registered nurses. The interviews were recorded, transcribed and lastly analyzed from Hsieh and Shannon’s description of qualitative content analysis.

    Result: Six categories were identified; Effects of Outlocating Patients, Communication Between Caregivers, Competence Among Nursing Staff, Work Environment, Teamwork and Suggestions for Improvement. Together, these describe the nurses’ experiences of caring for satellite patients.

    Conclusion: Nurses’ experiences of caring for these patients were mainly characterized by a concern for patient safety. The participants also mentioned that nurses’ work environment and work terms needs to improve in order to open hospital beds, reduce the number of satellite patients and thereby maintain a safe and equivalent care. 

  • Public defence: 2017-06-07 10:15 Planck, Fysikhuset, Linköping
    Lai, Chung-Chuan
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Phase Formation of Nanolaminated Transition Metal Carbide Thin Films2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Research on inherently nanolaminated transition metal carbides is inspired by their unique properties combining metals and ceramics, such as higher damage tolerance, better machinability and lower brittleness compared to the binary counterparts, yet retaining the metallic conductivity. The interesting properties are related to their laminated structure, composed of transition-metalcarbide layers interleaved by non-transition-metal (carbide) layers. These materials in thin-film form are particularly interesting for potential applications such as protective coatings and electrical contacts. The goal of this work is to explore nanolaminated transition metal carbides from the aspects of phase formation and crystal growth during thin-film synthesis. This was realized by studying phases in select material systems synthesized from two major approaches, namely, fromdirect-deposition and post-deposition treatment.

    The first approach was used in studies on the Mo-Ga-C and Zr-Al-C systems. In the former system, intriguing properties have been predicted for the 3D phases and their 2D derivatives (socalled MXenes), while in the latter system, the phases are interesting for nuclear applications. In this work, the discovery of a new Mo-based nanolaminated ternary carbide, Mo2Ga2C, is evidenced from thin-film and bulk processes. Its structure was determined using theoretical and experimental techniques, showing that Mo2Ga2C has Ga double-layers in simple hexagonal stacking between adjacent Mo2C layers, and therefore is structurally very similar to Mo2GaC, except for the additional Ga layers. For the Zr-Al-C system, the optimization of phase composition and structure of Zr2Al3C4 in a thin-film deposition process was studied by evaluating the effect of deposition parameters. I concluded that the formation of Zr2Al3C4 is favored with a plasma flux overstoichiometric in Al, and with a minimum lattice-mismatch to the substrates. Consequently, epitaxial Zr2Al3C4 thin film of high quality were deposited on 4H-SiC(001) substrates at 800 °C.

    With the approach of post-deposition treatment, the studies were focused on a new method of thermally-induced selective substitution reaction of Au for the non-transition-metal layers in nanolaminated carbides. Here, the reaction mechanism has been explored in Al-containing (Ti2AlC

    and Ti3AlC2) and Ga-containing (Mo2GaC and Mo2Ga2C) phases. The Al and Ga in these phases were selectively replaced by Au while the carbide layers remained intact, resulting in the formation of new layered phases, Ti2Au2C, Ti3Au2C2, Mo2AuC, and Mo2(Au1-xGax)2C, respectively. The substitution reaction was explained by fast outward diffusion of the Al or Ga being attracted to the surface Au, in combination with back-filling of Au, which is chemically inert to the carbide layers,to the vacancies.

    The substitution reaction was further applied to Ga-containing nanolaminated carbides, (Cr0.5Mn0.5)2GaC and Mo2GaC, motivated by development of novel magnetic nanolaminates. The former experiment resulted in the formation of (Cr0.5Mn0.5)2AuC, where the retained (Cr0.5Mn0.5)2C layers allowed a comparative study on the magnetic properties under the exchange of Ga for Au. After Au substitution, reduction in the Curie temperature and the saturation magnetization were observed, showing a weakened magnetic exchange interaction of the magnetic (Cr0.5Mn0.5)Clayers across the Au. In the Mo2GaC case, an Fe-containing MAX phase, Mo2AC with 50 at.% of Fe on the A site, was synthesized through selective substitution of Au-Fe alloy for the Ga layers, showing the first direct evidence for Fe in the MAX-phase structure. The substitution of Fe did not take place on another Mo2GaC sample tested for Fe exchange only, indicating the essential role of Au in catalyzing the Fe-substitution reaction.

    The knowledge gained from this thesis work contributes to improved approaches for attaining thin films of nanolaminated transition metal carbides with desired phase composition and crystal quality. The reports on the new nanolaminated phases through exchange interactions are likely to expand the family of nanolaminated carbides and advance their properties, and trigger more studies on related (quasi-) 2D materials.

    List of papers
    1. Mo2Ga2C: a new ternary nanolaminated carbide
    Open this publication in new window or tab >>Mo2Ga2C: a new ternary nanolaminated carbide
    Show others...
    2015 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 51, no 30, 6560-6563 p.Article in journal (Refereed) Published
    Abstract [en]

    We report the discovery of a new hexagonal Mo2Ga2C phase, wherein two Ga layers - instead of one - are stacked in a simple hexagonal arrangement in between Mo2C layers. It is reasonable to assume this compound is the first of a larger family.

    Place, publisher, year, edition, pages
    Royal Society of Chemistry, 2015
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-117813 (URN)10.1039/c5cc00980d (DOI)000352269000022 ()25768789 (PubMedID)
    Note

    Funding Agencies|Swedish Research Council [621-2011-4420, 642-2013-8020, 621-2014-4890]; Swedish Foundation for Strategic Research through the Synergy Grant FUNCASE Functional Carbides for Advanced Surface Engineering; Future Research Leaders 5 Program; ERC [258509]; Ningbo Natural Science Foundation [2013A610128]; National Natural Science Foundation of China [U1232136]; Knut and Alice Wallenberg Foundation

    Available from: 2015-05-11 Created: 2015-05-08 Last updated: 2017-05-15
    2. Structural and chemical determination of the new nanolaminated carbide Mo2Ga2C from first principles and materials analysis
    Open this publication in new window or tab >>Structural and chemical determination of the new nanolaminated carbide Mo2Ga2C from first principles and materials analysis
    Show others...
    2015 (English)In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 99, 157-164 p.Article in journal (Refereed) Published
    Abstract [en]

    Following our recent discovery of a new nanolaminated carbide, Mo2Ga2C, we herein present a detailed structural and chemical analysis of this phase based on ab initio calculations, X-ray photoelectron spectroscopy, high resolution scanning transmission electron microscopy, and neutron powder diffraction. Calculations suggest an energetically and dynamically stable structure for C in the octahedral sites between the Mo layers, with Ga bilayers - stacked in a simple hexagonal arrangement - between the Mo2C layers. The predicted elastic properties are below those of the related nanolaminate Mo2GaC. The predicted structure, including lattice parameters and atomic positions, is experimentally confirmed. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

    Place, publisher, year, edition, pages
    PERGAMON-ELSEVIER SCIENCE LTD, 2015
    Keyword
    First principles; Phase stability; Nanolaminated material; Crystal structure; Mo2Ga2C
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-122193 (URN)10.1016/j.actamat.2015.07.063 (DOI)000362145400017 ()
    Note

    Funding Agencies|Swedish Research Council [621-2011-4420, 642-2013-8020, 621-2014-4890]; Swedish Foundation for Strategic Research through the Synergy Grant FUNCASE Functional Carbides for Advanced Surface Engineering; Future Research Leaders 5 Program; ERC [258509]; Knut and Alice Wallenberg Foundation

    Available from: 2015-10-26 Created: 2015-10-23 Last updated: 2017-05-15
  • Public defence: 2017-06-01 13:00 Belladonna, Linköping
    Jonsson, Åsa
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    How to create and analyze a Heart Failure Registry with emphasis on Anemia and Quality of Life2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background and aims

    Heart failure (HF) is a major cause of serious morbidity and death in the population and one of the leading medical causes of hospitalization among people older than 60 years. The aim of this thesis was to describe how to create and how to analyze a Heart Failure Registry with emphasis on Anemia and Quality of Life. (Paper I) We described the creation of the Swedish Heart Failure Registry (SwedeHF) as an instrument, which may help to optimize the handling of HF patients and show how the registry can be used to improve the management of patients with HF. (Paper II) In order to show how to analyze a HF registry we investigated the prevalence of anemia, its predictors, and its association with mortality and morbidity in a large cohort of unselected patients with HFrEF included in the SwedeHF, and to explore if there are subgroups of HF patients identifying high--‐risk patients in need of treatment. (Paper III) In order to show another way of analyzing a HF registry we assessed the prevalence of, associations with, and prognostic impact of anemia in patients with HFmrEF and HFpEF. (Paper IV) Finally we examined the usefulness of EQ--‐ 5D as a measure of patient--‐reported outcomes among HF patients using different analytical models and data from the SwedeHF, and comparing results about HRQoL for patients with HFpEF and HFrEF.

    Methods

    An observational study based on the SwedeHF database, consisting of about 70 variables, was undertaken to describe how a registry is created and can be used (Paper I). One comorbidity (anemia) was applied to different types of HF patients, HFrEF (EF <40%) (II) and HFmrEF (EF 40--‐49% ) or HFpEF (> 50%) (III) analyzing the data with different statistical methods. The usefulness of EQ--‐5D as measure of patient--‐ reported outcomes was studied and the results about HRQoL were compared for patients with HFpEF and HFrEF (IV).

    Results

    In the first paper (Paper I) we showed how to create a HF registry and presented some characteristics of the patients included, however not adjusted since this was not the purpose of the study. In the second paper (Paper II) we studied anemia in patients with HFrEF and found that the prevalence of anemia in HFrEF were 34 % and the most important independent predictors were higher age, male gender and renal dysfunction. One--‐year survival was 75 % with anemia vs. 81 % without (p<0,001). In the matched cohort after propensity score the hazard ratio associated with anemia was for all--‐cause death 1.34. Anemia was associated with greater risk with lower age, male gender, EF 30--‐39%, and NYHA--‐class I--‐II. In the third paper (Paper III) we studied anemia in other types of HF patients and found that the prevalence in the overall cohort in patients with EF > 40% was 42 %, in HFmrEF 38 % and in HFpEF (45%). Independent associations with anemia were HFpEF, male sex, higher age, worse New York Heart Association class and renal function, systolic blood pressure <100 mmHg, heart rate ≥70 bpm, diabetes, and absence of atrial fibrillation. One--‐year survival with vs. without anemia was 74% vs. 89% in HFmrEF and 71% vs. 84% in HFpEF (p<0.001 for all). Thus very similar results in paper II and III but in different types of HF patients. In the fourth paper (Paper IV) we studied the usefulness of EQ--‐5D in two groups of patients with HF (HFpEF and HFrEF)) and found that the mean EQ--‐5D index showed small reductions in both groups at follow--‐up. The patients in the HFpEF group reported worsening in all five dimensions, while those in the HFrEF group reported worsening in only three. The Paretian classification showed that 24% of the patients in the HFpEF group and 34% of those in the HFrEF group reported overall improvement while 43% and 39% reported overall worsening. Multiple logistic regressions showed that treatment in a cardiology clinic affected outcome in the HFrEF group but not in the HFpEF group (Paper IV).

    Conclusions

    The SwedeHF is a valuable tool for improving the management of patients with HF, since it enables participating centers to focus on their own potential for improving diagnoses and medical treatment, through the online reports (Paper I). Anemia is associated with higher age, male gender and renal dysfunction and increased risk of mortality and morbidity (II, III). The influence of anemia on mortality was significantly greater in younger patients in men and in those with more stable HF (Paper II, III). The usefulness of EQ--‐5D is dependent on the analytical method used. While the index showed minor differences between groups, analyses of specific dimensions showed different patterns of change in the two groups of patients (HFpEF and HFrEF). The Paretian classification identified subgroups that improved or worsened, and can therefore help to identify needs for improvement in health services (Paper IV).

    List of papers
    1. Heart failure registry: a valuable tool for improving the management of patients with heart failure
    Open this publication in new window or tab >>Heart failure registry: a valuable tool for improving the management of patients with heart failure
    2010 (English)In: European Journal of Heart Failure, ISSN 1388-9842, Vol. 12, no 1, 25-31 p.Article in journal (Refereed) Published
    Abstract [en]

    Guidelines on how to diagnose and treat patients with heart failure (HF) are published regularly. However, many patients do not fulfil the diagnostic criteria and are not treated with recommended drugs. The Swedish Heart Failure Registry (S-HFR) is an instrument which may help to optimize the handling of HF patients. The S-HFR is an Internet-based registry in which participating centres (units) can record details of their HF patients directly online and transfer data from standardized forms or from computerized patient documentation. Up to December 2007, 16 117 patients from 78 units had been included in the S-HFR. Of these, 10 229 patients had been followed for at least 1 year, and 2133 deaths were recorded. Online reports from the registry showed that electrocardiograms were available for 97% of the patients. Sinus rhythm was found in 51% of patients and atrial fibrillation in 38%. Echocardiography was performed in 83% of the patients. Overall, 77% of patients were treated with angiotensin converting enzyme inhibitors or angiotensin II receptor blockers, 80% were on beta-blockers, 34% on aldosterone antagonists, and 83% on diuretics. The S-HFR is a valuable tool for improving the management of patients with HF, since it enables participating centres to focus on their own potential for improving diagnoses and medical treatment, through the online reports provided.

    Keyword
    Heart failure; Registry; Diagnostics; Medical treatment
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-52877 (URN)10.1093/eurjhf/hfp175 (DOI)
    Available from: 2010-01-13 Created: 2010-01-12 Last updated: 2017-05-15
    2. A comprehensive assessment of the association between anemia, clinical covariates and outcomes in a population-wide heart failure registry
    Open this publication in new window or tab >>A comprehensive assessment of the association between anemia, clinical covariates and outcomes in a population-wide heart failure registry
    Show others...
    2016 (English)In: International Journal of Cardiology, ISSN 0167-5273, E-ISSN 1874-1754, Vol. 211, 124-131 p.Article in journal (Refereed) Published
    Abstract [en]

    Background: The aim was to investigate the prevalence of, predictors of, and association with mortality and morbidity of anemia in a large unselected cohort of patients with heart failure (HF) and reduced ejection fraction (HFrEF) and to explore if there were specific subgroups of high risk. Methods: In patients with HFrEF in the Swedish Heart Failure Registry, we assessed hemoglobin levels and associations between baseline characteristics and anemia with logistic regression. Using propensity scores for anemia, we assessed the association between anemia and outcomes with Cox regression, and performed interaction and sub-group analyses. Results: There were 24 511 patients with HFrEF (8303 with anemia). Most important independent predictors of anemia were higher age, male gender and renal dysfunction. One-year survival was 75% with anemia vs. 81% without (p &lt; 0.001). In the matched cohort after propensity score the hazard ratio associated with anemia was for all-cause death 1.34 (1.28-1.40; p &lt; 0.0001), CV mortality 1.28 (1.20-1.36; p &lt; 0.0001), and combined CV mortality or HF hospitalization 1.24 (1.18-1.30; p &lt; 0.0001). In interaction analyses, anemia was associated with greater risk with lower age, male gender, EF 30-39%, and NYHA-class I-II. Conclusion: In HFrEF, anemia is associated with higher age, male gender and renal dysfunction and increased risk of mortality and morbidity. The influence of anemia on mortality was significantly greater in younger patients, in men, and in those with more stable HF. The clinical implication of these findings might be in the future to perform targeted treatment studies. (C) 2016 Elsevier Ireland Ltd. All rights reserved.

    Place, publisher, year, edition, pages
    ELSEVIER IRELAND LTD, 2016
    Keyword
    Heart failure; Reduced ejection fraction; Anemia; Outcomes; Observational study
    National Category
    Mathematics Clinical Medicine
    Identifiers
    urn:nbn:se:liu:diva-127741 (URN)10.1016/j.ijcard.2016.02.144 (DOI)000373918100029 ()26999301 (PubMedID)
    Note

    Funding Agencies|Swedish National Board of Health and Welfare; Swedish Association of Local Authorities and Regions; Swedish Society of Cardiology; Linkoping University; Swedish HF Registry foundation

    Available from: 2016-05-12 Created: 2016-05-12 Last updated: 2017-05-15
  • Public defence: 2017-06-09 09:00 Plank, Fysikhuset, Linköping
    Fallahshahroudi, Amir
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Domestication Effects on the Stress Response in Chickens: Genetics, Physiology, and Behaviour2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Animal domestication, the process where animals become adapted to living in proximity to humans, is associated with the alteration of multiple traits, including decreased fearfulness and stress response. With an estimated population of 50 billion, the domesticated chicken is the most populous avian species in the world. Hundreds of chicken breeds have been developed for meat and egg production, hobby or research purposes. Multidirectional selection and the relaxation of natural selection in captivity have created immense phenotypic diversity amongst domesticates in a relatively short evolutionary time. The extensive phenotypic diversity, existence of the wild ancestor, and feasibility of intercrossing various breeds makes the chicken a suitable model animal for deciphering genetic determinants of complex traits such as stress response. We used chicken domestication as a model to gain insights about the mechanisms that regulate stress response in an avian species. We studied behavioural and physiological stress response in the ancestral Red Junglefowl and one of its domesticated progenies, White Leghorn. An advanced intercross between the aforementioned breeds was later used to map genetic loci underlying modification of stress response. The general pattern of the stress response in chickens was comparable with that reported in mammals, however we identified distinctive differences in the stress modulatory pathways in chickens. We showed that changes in the expression levels of several stress modulatory genes in the brain, the pituitary and the adrenal glands underlie the observed modified stress response in domesticated chickens. Using quantitative trait loci (QTL) mapping, several QTL underlying stress induced corticosterone, aldosterone and baseline dehydroepiandrosterone (DHEA) levels were detected. As a next step, we combined QTL mapping with gene expression (eQTL) mapping and narrowed two QTL down to the putative causal genes, SERPINA10 and PDE1C. Both of these genes were differentially expressed in the adrenal glands of White Leghorn and the Red Junglefowl, had overlapping eQTL with hormonal QTL, and their expression levels in the adrenal glands were correlated with plasma levels of corticosterone and al-dosterone. These two genes thus serve as strong candidates for further functional investigation concerning modification of the stress response during domestication. This dissertation increase the knowledge about genetics and physiology of the stress response in an avian species and its modification during domestication. Our findings expand the basic knowledge about the stress response in chicken, which can potentially be used to improve welfare through appropriate genetic selection.

    List of papers
    1. Domestication effects on behavioural and hormonal responses to acute stress in chickens
    Open this publication in new window or tab >>Domestication effects on behavioural and hormonal responses to acute stress in chickens
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    2014 (English)In: Physiology and Behavior, ISSN 0031-9384, E-ISSN 1873-507X, Vol. 133, 161-169 p.Article in journal (Refereed) Published
    Abstract [en]

    Comparative studies have shown that alterations in physiology, morphology and behaviour have arisen due tothe domestication. A driving factor behind many of the changes could be a shift in stress responses,withmodifiedendocrine and behavioural profiles. In the present study we compared two breeds of chicken (Gallus gallus), thedomesticWhite Leghorn (WL) egg laying breed and its ancestor, the Red Junglefowl (RJF). Birds were exposed toan acute stress event, invoked by 3 or 10 min of physical restraint. Theywere then continuouslymonitored for theeffects on a wide range of behaviours during a 60 min recovery phase. Blood samples were collected from thechicken at baseline, and after 10 and 60 min following a similar restraint stress, and the samples wereanalyzed for nine endogenous steroids of the HPA and HPG axes. Concentration of the steroids was determinedusing validated liquid chromatography tandem mass spectrometry methods. In RJF, an immediate behaviouralresponse was observed after release from restraint in several behaviours, with a relatively fast return to baselinewithin 1 h. In WL, somebehaviourswere affected for a longer period of time, and others not at all. Concentrationsof corticosterone increasedmore in RJF, but returned faster to baseline compared toWL. A range of baseline levelsfor HPG-related steroids differed between the breeds, and they were generally more affected by the stress in WLthan in RJF. In conclusion, RJF reacted stronger both behaviourally and physiologically to the restraint stress, butalso recovered faster. This would appear to be adaptive under natural conditions, whereas the stress recovery ofdomesticated birds has been altered by domestication and breeding for increased reproductive output.

    Place, publisher, year, edition, pages
    Elsevier, 2014
    Keyword
    Corticosterone Recovery Restraint White Leghorn Red Junglefowl
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:liu:diva-107167 (URN)10.1016/j.physbeh.2014.05.024 (DOI)000340315100022 ()
    Note

    Funders: Swedish Research Council (VR) [621-2011-4731]; Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS) [221-2011-1088]; ERC (project Genewell) [322206]; Swedish Centre of Excellence in Animal Welfare; ARUP Institute for Clinical and Experimental Pathology

    Available from: 2014-06-09 Created: 2014-06-09 Last updated: 2017-05-15
    2. Domestication Effects on Stress Induced Steroid Secretion and Adrenal Gene Expression in Chickens
    Open this publication in new window or tab >>Domestication Effects on Stress Induced Steroid Secretion and Adrenal Gene Expression in Chickens
    Show others...
    2015 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, 1-10 p., 15345Article in journal (Refereed) Published
    Abstract [en]

    Understanding the genetic basis of phenotypic diversity is a challenge in contemporary biology. Domestication provides a model for unravelling aspects of the genetic basis of stress sensitivity. The ancestral Red Junglefowl (RJF) exhibits greater fear-related behaviour and a more pronounced HPA-axis reactivity than its domesticated counterpart, the White Leghorn (WL). By comparing hormones (plasmatic) and adrenal global gene transcription profiles between WL and RJF in response to an acute stress event, we investigated the molecular basis for the altered physiological stress responsiveness in domesticated chickens. Basal levels of pregnenolone and dehydroepiandrosterone as well as corticosterone response were lower in WL. Microarray analysis of gene expression in adrenal glands showed a significant breed effect in a large number of transcripts with over-representation of genes in the channel activity pathway. The expression of the best-known steroidogenesis genes were similar across the breeds used. Transcription levels of acute stress response genes such as StAR, CH25 and POMC were upregulated in response to acute stress. Dampened HPA reactivity in domesticated chickens was associated with changes in the expression of several genes that presents potentially minor regulatory effects rather than by means of change in expression of critical steroidogenic genes in the adrenal.

    Place, publisher, year, edition, pages
    Nature Publishing Group, 2015
    National Category
    Bioinformatics and Systems Biology
    Identifiers
    urn:nbn:se:liu:diva-122305 (URN)10.1038/srep15345 (DOI)000362885300001 ()26471470 (PubMedID)
    Note

    Funding agencies: Swedish Research Council (VR) [621-2011-4731]; Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS) [221-2011-1088]; SRC [621-2011-5523]; ERC [322206]; Swedish Centre of Excellence in Animal Welfare

    Available from: 2015-10-28 Created: 2015-10-28 Last updated: 2017-05-15
    3. Genetic and Targeted eQTL Mapping Reveals Strong Candidate Genes Modulating the Stress Response During Chicken Domestication.
    Open this publication in new window or tab >>Genetic and Targeted eQTL Mapping Reveals Strong Candidate Genes Modulating the Stress Response During Chicken Domestication.
    Show others...
    2017 (English)In: G3: Genes, Genomes, Genetics, ISSN 2160-1836, E-ISSN 2160-1836, Vol. 7, no 2Article in journal (Refereed) Published
    Abstract [en]

    The stress response has been largely modified in all domesticated animals, offering a strong tool for genetic mapping. In chickens, ancestral Red Junglefowl react stronger both in terms of physiology and behavior to a brief restraint stress than domesticated White Leghorn, demonstrating modified functions of the hypothalamic-pituitary-adrenal (HPA) axis. We mapped quantitative trait loci (QTL) underlying variations in stress-induced hormone levels using 232 birds from the 12th generation of an advanced intercross between White Leghorn and Red Junglefowl, genotyped for 739 genetic markers. Plasma levels of corticosterone, dehydroepiandrosterone (DHEA), and pregnenolone (PREG) were measured using LC-MS/MS in all genotyped birds. Transcription levels of the candidate genes were measured in the adrenal glands or hypothalamus of 88 out of the 232 birds used for hormone assessment. Genes were targeted for expression analysis when they were located in a hormone QTL region and were differentially expressed in the pure breed birds. One genome-wide significant QTL on chromosome 5 and two suggestive QTL together explained 20% of the variance in corticosterone response. Two significant QTL for aldosterone on chromosome 2 and 5 (explaining 19% of the variance), and one QTL for DHEA on chromosome 4 (explaining 5% of the variance), were detected. Orthologous DNA regions to the significant corticosterone QTL have been previously associated with the physiological stress response in other species but, to our knowledge, the underlying gene(s) have not been identified. SERPINA10 had an expression QTL (eQTL) colocalized with the corticosterone QTL on chromosome 5 and PDE1C had an eQTL colocalized with the aldosterone QTL on chromosome 2. Furthermore, in both cases, the expression levels of the genes were correlated with the plasma levels of the hormones. Hence, both these genes are strong putative candidates for the domestication-induced modifications of the stress response in chickens. Improved understanding of the genes associated with HPA-axis reactivity can provide insights into the pathways and mechanisms causing stress-related pathologies.

    Place, publisher, year, edition, pages
    The Genetics Society, 2017
    Keyword
    animal, domestication, quantitative trait, genes, corticosterone, aldosterone
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:liu:diva-134649 (URN)10.1534/g3.116.037721 (DOI)000394357100015 ()27974436 (PubMedID)
    Note

    Funding agencies: Swedish Research Council (SRC) (Vetenskapsradet) [621-2011-4731]; Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (Forskningsradet for Miljo, Areella Naringar och Samhallsbyggande) [221-2011-1088]; European Research Co

    Available from: 2017-02-21 Created: 2017-02-21 Last updated: 2017-05-15
    4. QTL mapping of stress related gene expression in a cross between domesticated chickens and ancestral red junglefowl.
    Open this publication in new window or tab >>QTL mapping of stress related gene expression in a cross between domesticated chickens and ancestral red junglefowl.
    Show others...
    2017 (English)In: Molecular and Cellular Endocrinology, ISSN 0303-7207, E-ISSN 1872-8057, Vol. 446, 52-58 p., S0303-7207(17)30090-4Article in journal (Refereed) Published
    Abstract [en]

    Domestication of animals is associated with numerous alterations in physiology, morphology, and behavior. Lower reactivity of the hypothalamic-pituitary-adrenal (HPA) axis and reduced fearfulness is seen in most studied domesticates, including chickens. Previously we have shown that the physiological stress response as well as expression levels of hundreds of genes in the hypothalamus and adrenal glands are different between domesticated White Leghorn and the progenitor of modern chickens, the Red Junglefowl. To map genetic loci associated with the transcription levels of genes involved in the physiological stress response, we conducted an eQTL analysis in the F12 generation of an inter-cross between White Leghorn and Red Junglefowl. We selected genes for further studies based on their known function in the regulation of the HPA axis or sympathoadrenal (SA) system, and measured their expression levels in the hypothalamus and the adrenal glands after a brief stress exposure (physical restraint). The expression values were treated as quantitative traits for the eQTL mapping. The plasma levels of corticosterone were also assessed. We analyzed the correlation between gene expression and corticosterone levels and mapped eQTL and their potential effects on corticosterone levels. The effects on gene transcription of a previously found QTL for corticosterone response were also investigated. The expression levels of the glucocorticoid receptor (GR) in the hypothalamus and several genes in the adrenal glands were correlated with the post-stress levels of corticosterone in plasma. We found several cis- and trans-acting eQTL for stress-related genes in both hypothalamus and adrenal. In the hypothalamus, one eQTL for c-FOS and one QTL for expression of GR were found. In the adrenal tissue, we identified eQTL for the genes NR0B1, RGS4, DBH, MAOA, GRIN1, GABRB2, GABRB3, and HSF1. None of the found eQTL were significant predictors of corticosterone levels. The previously found QTL for corticosterone was associated with GR expression in hypothalamus. Our data suggests that domestication related modification in the stress response is driven by changes in the transcription levels of several modulators of the HPA and SA systems in hypothalamus and adrenal glands and not by changes in the expression of the steroidogenic genes. The presence of eQTL for GR in hypothalamus combined with the negative correlation between GR expression and corticosterone response suggests GR as a candidate for further functional studies regarding modification of stress response during chicken domestication.

    Keyword
    Animal domestication, HPA axis, QTL, Stress response, eQTL
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:liu:diva-136027 (URN)10.1016/j.mce.2017.02.010 (DOI)000399509600006 ()28189567 (PubMedID)
    Note

    Funding agencies: Swedish Research Council (VR) [621-2011-4731]; Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS) [221-2011-1088]; ERC [Genewell 322206]; SRC grant [VR 621-2011-4423, 2015-4870]; Swedish Centre of Excellence in A

    Available from: 2017-03-27 Created: 2017-03-27 Last updated: 2017-05-18
  • Public defence: 2017-06-13 09:15 Planck, Fysikhuset, Linköping
    Gudmundson, Sara
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, Faculty of Science & Engineering.
    Species Responses to Environmental Fluctuations: impacts of food web interactions and noise color2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Species constantly experience changes in their environmental conditions owing to natural or human induces reasons. Understanding how species respond to these fluctuations are important for ecology, especially given the ongoing climate change. Empirical studies have shown that species respond differently to the same disturbance. However, our knowledge of what create these differences in the environmental response is limited and in most cases based on studies focusing on single species. In this thesis, I have taken a theoretical approach and used dynamical models to investigate how the population dynamics of species are affected by species-species interactions and environmental fluctuations.

     

    In the first paper (Paper I) I investigated how a species respond to environmental fluctuations when isolated or embedded in a food web. The study showed that species-species interactions had an effect in temporally positively autocorrelated environments (red noise) but not in uncorrelated environments (white noise). This was owing to species following their equilibrium densities in red environments which in turn enabled species-species interactions to come into play. Red environmental variables are more prominent in nature than white. Thus, these results show the importance of using a food web approach when analyzing species response to environmental fluctuations.

     

    The most commonly discussed effect of climate change is an elevated mean temperature. This shift is expected to affect the growth rate of many species. However, there is no robust theory of how we should expect species in food webs to respond to a rise in temperature. In the second paper (Paper II) I defined and studied the dynamic rate of food webs

    (DR) acting analogously to single species growth rate. I found that the higher DR the easier for species population densities to follow their equilibrium over time. Both DR and noise color changed the temporal relationship between the population and the environmental noise. Thus, it is of major importance to take the scale of time into consideration when investigating species response to environmental fluctuations.

     

    Another important factor which affect population dynamics is species spatial distributions. Dispersal between subpopulations enable individuals to rescue or prolong the time to extinction for the population seen as a whole. In the third paper (Paper III), I investigated how species in food webs respond to environments that varies both in time and space and compared the results with the one from single species. I found that single species were stabilized by an increased dispersal rate independent of the noise color. Species-species interactions had an effect for some of the species in these landscapes.

    At red asynchronous noise, one resource species in each food web had a local minimum in stability at low dispersal rate. Here, dispersal decoupled local population dynamics and prevented species from tracking their equilibriums. At high dispersal rates, all resource species and their single species counterparts were stabilized by dispersal as local patch dynamics lost its importance. Environmental noise together with the spatial dimension does seem to explain much of the stability properties of species on our planet.

     

    However, natural ecosystems are much more complex and species rich than the food web models I have used so far. Theoreticians have previously had a hard time describing stable complex systems that survive environmental fluctuations. Thus, in my fourth and last project (Paper

    IV) I investigated how species population dynamics are affected by environmental fluctuations when embedded in larger food webs. These systems were built by connecting food web modules with periodic boundary conditions (PBC). The PBC method has previously helped physicists to understand the nature of waves and particles by removing the edges in systems. I found that food web size does not have to have a negative effect on food web stability. I showed that by removing the destabilizing effect of edges it is possible to describe large stable food webs, more similar to natural ecosystems.

     

    Overall, the research presented here give new insights into species responses to environmental fluctuations. They especially highlight the importance of considering both species interactions and environmental noise color when studying population dynamics in a fluctuating environment. A food web approach is necessary when analyzing species population dynamics and planning for conservation actions, especially when studying the effects of climate change on biodiversity.

    List of papers
    1. Environmental variability uncovers disruptive effects of species interactions on population dynamics
    Open this publication in new window or tab >>Environmental variability uncovers disruptive effects of species interactions on population dynamics
    2015 (English)In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 282, no 1812, 67-75 p.Article in journal (Refereed) Published
    Abstract [en]

    How species respond to changes in environmental variability has been shown for single species, but the question remains whether these results are transferable to species when incorporated in ecological communities. Here, we address this issue by analysing the same species exposed to a range of environmental variabilities when (i) isolated or (ii) embedded in a food web. We find that all species in food webs exposed to temporally uncorrelated environments (white noise) show the same type of dynamics as isolated species, whereas species in food webs exposed to positively autocorrelated environments (red noise) can respond completely differently compared with isolated species. This is owing to species following their equilibrium densities in a positively autocorrelated environment that in turn enables species species interactions to come into play. Our results give new insights into species response to environmental variation. They especially highlight the importance of considering both species interactions and environmental autocorrelation when studying population dynamics in a fluctuating environment.

    Place, publisher, year, edition, pages
    ROYAL SOC, 2015
    Keyword
    environmental autocorrelation; environmental tracking; food webs; indirect effects; paradox of enrichment; population stability
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:liu:diva-122442 (URN)10.1098/rspb.2015.1126 (DOI)000362305500008 ()26224705 (PubMedID)
    Note

    Funding Agencies|Linkoping University

    Available from: 2015-11-03 Created: 2015-11-02 Last updated: 2017-05-15
  • Maslyannikov, Lev
    Linköping University, Department of Management and Engineering, Commercial and Business Law.
    Skadebegränsningsprincipen: – den skadelidandes skyldighet att begränsa sin skada2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The doctrine of avoidable loss is a generally recognized principle in Swedish law. The doctrine is often invoked in damage claim disputes of all kinds, and is therefore important in practice. There is plenty of legal literature where the doctrine is treated in the context of sales law and insurance law. On the tort law side, however, there is nothing – this is the first dedicated work on the subject in Sweden.

    There are many tort cases where the question of avoidable loss is actualized, but due to the way the courts articulate the grounds for their rulings, the cases provide little guidance for the future, and therefore have little value as precedent. This is not necessarily an obstacle to the study. On the contrary, when looking outwards, I have found a wealth of ideas and study material in other areas of civil law, in law and economics, and in foreign law. The structural and methodological framework of the thesis was designed to allow for extraction of material from foreign sources without needing to conduct a thorough (and often uninteresting) comparative study.

    The main purpose of the investigation was to define the boundaries of the claimant’s liability as imposed by the doctrine. Considering the limited scope of the thesis, it would not have been possible to deconstruct the subject into details and conduct thorough investigations of those. Instead, the work was focused on determining general guidelines, thought patterns and clues; both de lege lata and de lege ferenda. Multiple such guidelines could be defined in various contexts where the doctrine is applied, but also, interestingly, in certain contexts where it is not obvious that considerations of avoidable loss are decisive. Multiple systemic issues have also been found, both in the application of the doctrine and in the underlying norms. I have humbly put forward several suggestions on how these issues could be alleviated to promote legal certainty in the doctrine’s application, both today and in the future.

  • Jonsson, Andreas
    Linköping University, Department of Management and Engineering, Commercial and Business Law.
    Försäkring av affärsrisker: Var dras gränsen i ansvarsförsäkringen och var borde den dras?2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis, I examine what insurance is, together with what business risk is and how business risks are insured in the context of liability insurance. Important questions are where, and why, the boundaries of the insurability of business risks are set as they are, and also whether a new structure and systematics could give rise to a more suitable delimitation.

    To be able to understand and argue about how business risks are treated in the context of liability insurance, and also to be able to approach the sphere of the subject holistically, a relation to the essence of insurance must first be built. The knowledge about what insurance is and why it exists is an indispensable foundation for the argumentation around the insurability of business risks. The principles and the normative base that make up the legal area of insurance law reveal the framework of the relationship between the parties of the insurance contract and the requirements of insurability. These principles and norms subsequently form the background against which the business risks are seen in the analysis.

    The liability insurance covers the liability of the insured. A distinction can be made between how the insurance covers contractual liability and non-contractual liability. Since professional liability, such as the liability of advisors, is treated differently from the liability of other service businesses, there is a principal benefit in elucidating it separately. The business risks lead to a potential liability, and how they are treated can be seen in the regular and global liability insurance policies. In this thesis, the following expanding and excluding policies are covered. Exclusion of pure financial loss, property in trust, promise or guarantee, foreseeable damage and damage to delivered property. Addition of pure financial loss, recall, claims due to ingredients or components, access and restoration costs, and goodwill.

    The boundary of coverage of business risks in the context of liability insurance is fuzzy and does not appear to be set based upon any underlying systematics. The common denominators are, however, analyzed which gives an idea of the ends that the insurance industry wants to achieve through the delimitation against certain business risks. With knowledge of what constitutes the essence of insurance, of how and why the boundaries are set as they are and of their, from a purpose-oriented point of view, not entirely satisfactory results, a new structure and systematics can be proposed. Hopefully, it leads to a more thought-out and comprehensible treatment of business risks in matters regarding liability insurance.

  • Duda, L.-C.
    et al.
    Department of Physics,Uppsala University, Uppsala, Sweden.
    Schmitt, T.
    Department of Physics,Uppsala University, Uppsala, Sweden / Swiss Light Source, Paul Scherrer Institute, Switzerland.
    Magnuson, Martin
    Department of Physics,Uppsala University, Uppsala, Sweden.
    Forsberg, J.
    Department of Physics,Uppsala University, Uppsala, Sweden.
    Olsson, A.
    Department of Physics,Uppsala University, Uppsala, Sweden.
    Nordgren, J.
    Department of Physics,Uppsala University, Uppsala, Sweden.
    Okada, K.
    The Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan.
    Kotani, A.
    RIKEN/Spring8,1-1-1 Kouto, Mikazuki-cho, Saya-gun, Hyogo,Japanand / Photon Factory, IMSS, High Energy Accelerator Research Organization,Tsukuba, Ibaragi, Japan .
    Resonant inelastic X-ray scattering at the NiO O K-resonance: non-local charge-transfer and double singlet excitations2007In: MAX-lab: Activity Report 2005-2006 / [ed] U. Johansson, A. Nyberg, R. Nyholm, H. Ullman, Lund: MAX-lab , 2007, 270-271 p.Chapter in book (Other academic)
    Abstract [en]

    NiO is one of the prototypical compounds that has highlighted the importance of correlation effects in transition metal oxides. Core level spectroscopies bear evidence for the highly correlated nature of low energy excitations. For instance, the asymmetry of the Ni2p-line shape has been attributed to non-local charge transfer excitations and multi-site cluster calculations show that solidstate effects generally are appreciable for correlated materials, such as cuprates and high Tc-compounds.....

  • Unnikrishnan, Vishnu
    et al.
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Vesterbacka, Mark
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Mitigation of Sampling Errors in VCO-Based ADCs2017In: IEEE Transactions on Circuits and Systems Part 1: Regular Papers, ISSN 1549-8328, E-ISSN 1558-0806, no 99, 1-10 p.Article in journal (Refereed)
    Abstract [en]

    Voltage-controlled-oscillator-based analog-to-digital converter (ADC) is a scaling-friendly architecture to build ADCs in fine-feature complimentary metal-oxide-semiconductor processes. Lending itself to an implementation with digital components, such a converter enables design automation with existing digital CAD hence reducing design and porting costs compared with a custom design flow. However, robust architectures and circuit techniques that reduce the dependence of performance on component accuracy are required to achieve good performance while designing converters with low accuracy components like standard cells in deeply-scaled processes. This paper investigates errors resulting from the sampling of a fast switching multi-phase ring oscillator output. A scheme employing ones-counters is proposed to encode the sampled ring oscillator code into a binary representation, which is resilient to a class of sampling induced errors modeled by the temporal reordering of the transitions in the ring. In addition to correcting errors caused by deterministic reordering, proposed encoding suppresses conversion errors in the presence of arbitrary reordering patterns that may result from automatic place-and-route in wire-delay dominated processes. The error suppression capability of the encoding is demonstrated using MATLAB simulation. The proposed encoder reduces the error caused by the random reordering of six subsequent bits in the sampled signal from 31 to 2 LSBs for a 31-stage oscillator.

  • Guo, J.-H.
    et al.
    Department of Physics, Uppsala University, Uppsala, Sweden.
    Magnuson, Martin
    Department of Physics, Uppsala University, Uppsala, Sweden.
    Såthe, C.
    Department of Physics, Uppsala University, Uppsala, Sweden.
    Nordgren, J.
    Department of Physics, Uppsala University, Uppsala, Sweden.
    Yang, L.
    Department of Physics and Measurement Technology, Linköping University, Linköping, Sweden.
    Luo, Y.
    Department of Physics and Measurement Technology, Linköping University, Linköping, Sweden.
    Ågren, H.
    Department of Physics and Measurement Technology, Linköping University, Linköping, Sweden.
    Xing, K.
    Department of Physics and Measurement Technology, Linköping University, Linköping, Sweden.
    Johansson, N.
    Department of Physics and Measurement Technology, Linköping University, Linköping, Sweden.
    Salaneck, William R
    Department of Physics and Measurement Technology, Linköping University, Linköping, Sweden.
    Daik, R.
    IRC in polymer Science and Technology, Durham University, Durham, UK.
    Feast, W. J.
    IRC in polymer Science and Technology, Durham University, Durham, UK.
    How the phenyle rings (benzene) act as building blocks in pi conjugated polymers1998In: Advanced Light Source: Compendium of User Abstractsand Technical Reports1993-1996 / [ed] Deborah J. Dixon, jane Cross, Kathryn Devereaux, and Annette Greiner, Berkeley: Ernest Orlando Lawrence Berkeley National Laboratory, University of California Berkeley, California, USA , 1998, 129-132 p.Chapter in book (Other academic)
    Abstract [en]

    Organic conjugated polymers have the electronic structure of semiconductors and can be doped to become good conductors (1). Conjugated polymers are now used as active materials in a wide variety of prototype applications such as light emitting diodes [2] and organic transistors [3,4]. Most of the interesting chemistry and physics of conjugated polymers is associated with the details of the electronic structure at the valence and conduction band edges and, in this connection, various electron spectroscopies can be used as tools for diagnosis of the relevant electronic and geometric properties....