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  • Martinsson, Bengt-Göran
    et al.
    Linköping University, Faculty of Educational Sciences.
    Eriksson Barajas, Katarina
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Svenskämnets och de moderna språkens didaktik2020Other (Other academic)
  • Westerholm, Gustaf
    Linköping University, Department of Computer and Information Science.
    Automatic Configuration of Aircraft and Simulators2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    For development, sales, verification and validation purposes, flight simulations of the Saab JAS 39 Gripen E/F are often performed. For these type of simulations, one needs to be able to choose both a specific aircraft variant and a specific simulation setup and then generate the appropriate build files to build the simulator. This configuration process is currently mainly done manually and has numerous points of variation, some of these are in:

    ·       ACSim Kernel which simulates the components and systems of the aircraft. Around 150 models can be chosen out of almost 1000 total.

    ·       ACCS, the aircraft computers containing the aircraft software applications. Here, dozens of configuration-specific applications can be included in a configuration.

    Restricting the configuration possibilities are relations and constraints between components, systems, models and applications, but also credentials of the user, limiting available options.

    In this thesis it is examined to what degree this configuration process can be automated with a variant management tool, such as pure::variants, and possible ways of implementation are presented. A conclusion is that that the configuration of ACSim Kernel build files can be automated to a high degree, and for the ACCS system architecture studied in this thesis, build files can be automated to a lower degree. It is also shown how pure::variants can be used to filter its models for secrecy purposes, and how helpful system properties can be represented in pure::variants models. A suggestive example of how pure::variants can be used with short implementation time is provided and more labour intensive implementation suggestions are discussed.

  • Lundin, Jennifer
    et al.
    Linköping University, Department of Management and Engineering, Commercial and Business Law. Linköping University, Faculty of Arts and Sciences.
    Rydh, Dennis
    Linköping University, Department of Management and Engineering, Commercial and Business Law. Linköping University, Faculty of Arts and Sciences.
    Framtida beskattning av robotar: En studie i förhållande till kraven på god skattelagstiftning och befintliga beskattningsmetoder.2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Under de senaste åren har en internationell diskussion angående robotskatt blossat upp. Den tekniska utvecklingen sker snabbare än aldrig förr. Redan i dagsläget finns det teknik som möjliggör att hälften av dagens arbetsuppgifter skulle kunna automatiseras. Cirka 60 procent av Sveriges skatteintäkter kommer i dag från skatt på förvärvsarbete. Skulle hälften av dagens arbetsuppgifter automatiseras riskerar således staten och kommunerna att förlora en stor del skatteintäkter. Debatten är för närvarande i ett stadium då det diskuteras huruvida robotar bör eller inte bör beskattas. I detta studium anlägger vi ett skatterättsligt perspektiv på den debatterade frågan med syftet att tillföra debatten ytterligare en dimension. Svårigheterna med att utforma en robotskattelag är dels att definiera begreppet robot skatterättsligt dels att utreda om en robotskattelag skulle vara förenlig med de krav som ställs på en god skattelagstiftning. Kraven som ställs på en god skattelagstiftning verkar likt krafterna i ett spänningsfält. Vissa av kraven är till och med motstridiga och en god skattelagstiftning uppvisar en balans mellan dessa krav. I uppsatsen utreder vi huruvida en robotskatt, då den utformas i enlighet med någon av de tre befintliga beskattningsmetoderna punktskatt, objektskatt samt inkomstskatt på schablonintäkt, uppvisar en acceptabel balans mellan de krav som ställs på en god skattelagstiftning. Genom den analys vi företagit i uppsatsen har vi kommit fram till att en robotpunktskatt skulle vara relativt ineffektiv med hänsyn robotskattens fiskala primärmål. Däremot har vi kommit fram till att en robotobjektskatt samt inkomstskatt på robotschablonintäkt skulle kunna uppvisa en acceptabel balans mellan de krav som ställs på en god skattelagstiftning.

  • Public defence: 2020-04-30 13:15 I:101, I-Building, LinköpingOrder onlineBuy this publication >>
    Palmqvist, Lisa
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Time to Plan: How to support everyday planning in adolescents with intellectual disability2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Children and adolescents with intellectual disability (ID) have difficulties in executive functioning and when coping with everyday planning tasks. However, the literature cannot explain whether individuals with ID perform according to their developmental level or not. The studies in this thesis investigated if life experience could be a contributing factor to the diversity seen in the literature. Planning performance can be improved by either using external or internal support. Assistive technology for cognition (ATC) is an example of external support. This thesis investigated how the ATC is being used in an everyday planning situation which has not been investigated before. Furthermore, this thesis explored whether the internal supports of cognitive abilities and life experience correlate with planning ability in adolescents with ID, and if planning ability can be trained using a cognitive training program for everyday planning. Results showed that ATC supported cognitive functions, but that the children did not formulate the plans themselves. Furthermore, the results support the difference model of ID since planning correlated with different cognitive measures and life experience in adolescents with ID compared to children with a typical development. Adolescents with ID got better at the planning tasks in the training program, however, no transfer effects to untrained planning tasks were found. To conclude, the planning was supported by external and internal support. However, ATC needs to be designed and prescribed in a way that increases independence. Practitioners should actively support in training planning and should be cautious when introducing cognitive interventions if the transfer gap is too large.  

    List of papers
    1. Parents act as intermediary users for their children when using assistive technology for cognition in everyday planning: Results from a parental survey
    Open this publication in new window or tab >>Parents act as intermediary users for their children when using assistive technology for cognition in everyday planning: Results from a parental survey
    2019 (English)In: Assistive technology, ISSN 1040-0435, E-ISSN 1949-3614, p. 1-9Article in journal (Refereed) Published
    Abstract [en]

    Assistive Technology for Cognition (ATC) is employed by children with and without disabilities. However, how the ATC is used in everyday life has not been studied. The current study investigated ATC-usage in everyday planning in three groups: 1) children qualifying for Swedish habilitation centers (ID/ASD), 2) children with disability not qualifying for habilitation service (ADHD), and 3) children with typical development (TD). A parental survey was conducted (n = 192) and answers were analyzed with statistical tests and inductive thematic text analysis. Results showed that all groups used ATC, most in the Habilitation group and least in the TD group. According to parents, ATC supported cognitive functions in all groups, but it became evident that the parents were responsible for planning by setting up the ATC, whilst the children merely executed the plans. This was linked to several limitations, for example the design was not appropriately adapted for these groups. The implications for the practitioners are 1) evaluate the users? cognitive abilities and choose an ATC suitable for that individual rather focusing on the diagnosis, and 2) follow up usage to see if it is the parent or the child that are using the ATC.

    Place, publisher, year, edition, pages
    Taylor & Francis, 2019
    Keywords
    Activities of daily living, assessment, cognitive impairment, developmental disability, electronic aids to daily living, usability
    National Category
    Pediatrics
    Identifiers
    urn:nbn:se:liu:diva-164915 (URN)10.1080/10400435.2018.1522523 (DOI)
    Available from: 2020-04-01 Created: 2020-04-01 Last updated: 2020-04-01Bibliographically approved
    2. Cognitive abilities and life experience in everyday planning in adolescents with intellectual disabilities: Support for the difference model
    Open this publication in new window or tab >>Cognitive abilities and life experience in everyday planning in adolescents with intellectual disabilities: Support for the difference model
    2020 (English)In: Journal of Intellectual Disability Research, ISSN 0964-2633, E-ISSN 1365-2788Article in journal (Refereed) Epub ahead of print
    Abstract [en]

    Background The literature on planning ability in individuals with intellectual disability (ID) provides no clarity on whether their ability matches their mental age (MA) or not. Perhaps can planning experience explain the mixed results. The current study investigated to what extent cognitive abilities and life experience can explain everyday planning ability in individuals with ID and to what extent results from everyday planning tasks support the developmental or the difference model of ID. Method Planning tests, cognitive ability tasks and a self-rated life experience form were administered to 71 adolescents with ID and 62 children with a typical development matched on MA. Results Adolescents with ID exhibited planning ability according to their MA. Regression analyses showed that the predictors of planning differed between the groups. The cognitive measures could predict planning in both groups, but life experience only contributed positively to planning in the MA group, whereas chronological age was negatively correlated with successful planning in the ID group. Conclusions and discussion The results support the difference model of ID. When matched on MA, the individuals with ID will solve the planning task in a qualitatively different manner. Additionally, the participants with ID could not utilise their life experience when solving the planning task, contrary to the MA group. Practitioners should be aware that individuals with ID might need more everyday planning training throughout adolescence. To support adolescents with ID, practitioners may focus on supporting the individuals cognitive abilities rather than relying on their prior knowledge.

    Place, publisher, year, edition, pages
    WILEY, 2020
    Keywords
    cognitive abilities; difference model; errand task; everyday planning; intellectual disability
    National Category
    Occupational Therapy
    Identifiers
    urn:nbn:se:liu:diva-163409 (URN)10.1111/jir.12710 (DOI)000505491500001 ()31898385 (PubMedID)
    Note

    Funding Agencies|Stiftelsen Savstaholm [ST 2016-030]

    Available from: 2020-02-04 Created: 2020-02-04 Last updated: 2020-04-01
  • Eriksson, John
    Linköping University, Department of Computer and Information Science.
    Machine Learning for Predictive Maintenance on Wind Turbines: Using SCADA Data and the Apache Hadoop Ecosystem2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis explores how to implement a predictive maintenance system for wind turbines in Apache Spark using SCADA data. How to balance and scale the data set is evaluated, together with the effects of applying the algorithms available in Spark mllib to the given problem. These algorithms include Multilayer Perceptron (MLP), Linear Regression (LR), Random Forest (RF), Decision Tree (DT), Support Vector Machine (SVM) and Gradient Boosted Tree (GBT). This thesis also evaluates the effects of applying stacking and bagging algorithms in an attempt to decrease the variance and improve the metrics of the model. It is found that the MLP produces the most promising model for predicting failures on the given data set and that stacking multiple MLP models is a good way of producing a model with a lower variance than the individual base models. In addition to this, a function that creates a savings estimation is developed. Using this function, a time window function that explores the decisiveness of a model is created. The conclusion is made that a model is more decisive if the failure it predicts occurs in a turbine where it has been trained on failure data from that same component, indicating that there are unknown variables that affect the sensor data.

  • Public defence: 2020-05-05 09:00 Berzeliussalen, Building 463, LinköpingOrder onlineBuy this publication >>
    Toll, Rani
    Linköping University, Department of Biomedical and Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Department of Emergency Medicine in Linköping.
    To See or Not to See: A Study on Capillary Refill2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: Assessment of the critically ill is traditionally based on vital signs (blood pressure, pulse, respiratory rate, temperature and level of consciousness). Altered vital signs are, however, late indicators of deranged hemodynamics pointing to a need for additional, more sensitive markers of circulatory compromise. In the beginning of the 20th century, the capillary refill (CR) time evolved as a possible, non-invasive adjunct to early prediction of the outcome in the critically ill. The manoeuvre entails application of blanching pressure on the skin of the finger pulp or sternum for 5 seconds. After release of the pressure, the observer estimates time in seconds for the skin to return to original colour. This time is hypothesized to reflect the dynamics of the microcirculation and its possible connection with hemodynamics. In the 1980s the “normal capillary refill time” was set to < 2 seconds and later extended to 3 seconds, without a clear scientific foundation. Naked-eye estimations of CR time met increasing scepticism in the 1990s due to subjectivity and poor prognostic value for shock or death. Several basic traits, such as age and sex, as well as ambient temperature, were also shown to independently influence the CR time. Various methods have evolved with the capability to measure CR time quantitatively, one of which is Polarisation Spectroscopy Imaging (PSI). PSI measures the Red Blood Cell (RBC) concentration in tissue (e.g. the skin) and can be used to measure CR time.

    Objectives: The purpose of this study was to establish basic characteristics for quantified CR (qCR), identify possible influencing factors in healthy subjects and to investigate how this relates to current practice. We also sought to identify technical demands for transfer of the technique into clinical studies. In paper I we analysed the (qCR) time characteristics at 5 different skin sites (forehead, sternum, volar forearm, finger pulp and dorsum finger). The objective of paper II was to investigate the inter- and intra-observer variability of naked eye CR assessments of different professions, nurses, doctors and secretaries (representing laymen). In paper III we observed the effect of low ambient temperature on the qCR time in different skin sites. In paper IV, we transferred the equipment from a laboratory to a clinical setting in the Emergency Department (ED) for application on potentially critically ill patients. In this study we evaluated the most important factors determining a reliable data collection and influencing the amount of data possible to analyse.

    Methods: qCR time was measured in a total of 38 volunteers and 10 patients in different skin sites (2-5 skin sites) at different ambient temperatures. PSI (TiVi 600 and 700, WheelsBridge AB, Linköping, Sweden) was used to determine the rapid temporal changes in RBC concentration in skin during the CR manoeuvre. Films using a range of the first measurements from paper I were shown for assessment to 48 observers working in the ED.

    Results: In paper I we could delineate qCR curves and suggest 2 possible equivalents to the naked-eye observed CR time which we named Time to Return to Baseline 1 (tRtB1) and Time to Peak (tpk). We demonstrated differences in qCR-curves depending on skin site and possibly due to skin temperature. In paper II we showed a poor inter- and intra-observer reproducibility in visually estimating the CR time regardless of profession (clinicians or laymen). Paper III demonstrated a rapid effect of ambient temperature on qCR time in peripheral skin sites such as finger pulp. The forehead, regarded as a more central skin site was the most temperature stable site and showed least variability in qCR time as determined using tRtB1. Paper IV, a study on patients in an ED setting, yielded assayable data in 80% of the measurements. We identified critical performance parameters to address in the further development of a more robust, easy-to-use device for future validation of the possible relevance of qCR in patient triage and monitoring.

    Conclusions: CR time can be quantified using PSI. Quantified CR time demonstrated a large variability between different skin sites, specifically, skin temperature was shown to be an important factor influencing qCR time, particularly at the fingertip. Naked-eye estimates of CR time were highly variable, both within and between observers. Agreement between quantified CR time and naked-eye estimates was poor. The prototypic PSI technique was feasible in a clinical setting and, with further improvements, clinical evaluation of qCR in relation to relevant patient outcomes will be possible.

    List of papers
    1. Reflectance spectroscopy: to shed new light on the capillary refill test
    Open this publication in new window or tab >>Reflectance spectroscopy: to shed new light on the capillary refill test
    Show others...
    2018 (English)In: Journal of Biophotonics, ISSN 1864-063X, E-ISSN 1864-0648, Vol. 11, no 1, article id e201700043Article in journal (Refereed) Published
    Abstract [en]

    To use Bioengineering methodology is used to achieve, at five anatomical sites, a detailed, quantitative assessment of the return of blood content to the blanched area, during the Capillary Refill (CR) test. An observational, non-randomized, experimental study on 23 healthy subjects (14 females) was performed in our climate controlled skin physiology laboratory. Our main outcome measures were based on the chronological assessment and quantification of red blood cell concentration (RBC) after the release of blanching pressure in the CR test, using Tissue Viability Imaging (TiVi), a digital photographic technique based on polarisation spectroscopy. TiVi enabled collection of detailed data on skin RBC concentration during the CR test. The results were shown as curves with skin blood concentration (TiVi-value) on the y-axis and the time on the x-axis. Quantitative CR responses showed site and temperature variability. We also suggest possible objective endpoint values from the capillary refill curve. Detailed data on skin RBC concentration during the CR test is easily obtained and allows objective determination of end points not possible to achieve by naked eye assessment. These findings have the potential to place the utility of the CR test in a clinical setting in a new light. Picture: Regular photograph and TiVi Image showing CR test and corresponding graph for the CR response. [GRAPHICS] .

    Place, publisher, year, edition, pages
    Wiley-VCH Verlagsgesellschaft, 2018
    Keywords
    Capillary refill; microvasculature; circulation; skin imaging; gender variability; blood concentration
    National Category
    Dermatology and Venereal Diseases
    Identifiers
    urn:nbn:se:liu:diva-145478 (URN)10.1002/jbio.201700043 (DOI)000425294600022 ()28544641 (PubMedID)2-s2.0-85019540776 (Scopus ID)
    Available from: 2018-03-05 Created: 2018-03-05 Last updated: 2020-04-01Bibliographically approved
    2. Man versus machine: comparison of naked-eye estimation and quantified capillary refill
    Open this publication in new window or tab >>Man versus machine: comparison of naked-eye estimation and quantified capillary refill
    2019 (English)In: Emergency Medicine Journal, ISSN 1472-0205, E-ISSN 1472-0213, Vol. 36, no 8, p. 465-471Article in journal (Refereed) Published
    Abstract [en]

    Background Capillary refill (CR) time is traditionally assessed by naked-eye inspection of the return to original colour of a tissue after blanching pressure. Few studies have addressed intra-observer reliability or used objective quantification techniques to assess time to original colour. This study compares naked-eye assessment with quantified CR (qCR) time using polarisation spectroscopy and examines intra-observer and interobserver agreements in using the naked eye. Method A film of 18 CR tests (shown in a random fixed order) performed in healthy adults was assessed by a convenience sample of 14 doctors, 15 nurses and 19 secretaries (Department of Emergency Medicine, Linkoping University, September to November 2017), who were asked to estimate the time to return to colour and characterise it as fast, normal or slow. The qCR times and corresponding naked-eye time assessments were compared using the Kruskal-Wallis test. Three videos were shown twice without observers knowledge to measure intra-observer repeatability. Intra-observer categorical assessments were compared using Cohens Kappa analysis. Interobserver repeatability was measured and depicted with multiple-observer Bland-Altman plotting. Differences in naked-eye estimation between professions were analysed using ANOVA. Results Naked-eye assessed CR time and qCR time differ substantially, and agreement for the categorical assessments (naked-eye assessment vs qCR classification) was poor (Cohens kappa 0.27). Bland-Altman intra-observer repeatability ranged from 6% to 60%. Interobserver agreement was low as shown by the Bland-Altman plotting with a 95% limit of agreement with the mean of +/- 1.98 s for doctors, +/- 1.6 s for nurses and +/- 1.75 s for secretaries. The difference in CR time estimation (in seconds) between professions was not significant. Conclusions Our study suggests that naked-eye-assessed CR time shows poor reproducibility, even by the same observers, and differs from an objective measure of CR time.

    Place, publisher, year, edition, pages
    BMJ PUBLISHING GROUP, 2019
    National Category
    Anesthesiology and Intensive Care
    Identifiers
    urn:nbn:se:liu:diva-159714 (URN)10.1136/emermed-2018-207948 (DOI)000478913300006 ()31308133 (PubMedID)
    Note

    Funding Agencies|Region Ostergotland [LIO-532001, LIO-700271]

    Available from: 2019-08-19 Created: 2019-08-19 Last updated: 2020-04-01
    3. A cool response: the influence of ambient temperature on capillary refill time
    Open this publication in new window or tab >>A cool response: the influence of ambient temperature on capillary refill time
    Show others...
    2018 (English)In: Journal of Biophotonics, ISSN 1864-063X, E-ISSN 1864-0648, Vol. 11, no 6Article in journal (Refereed) Published
    Abstract [en]

    Objective

    To describe the effect of low ambient temperature on skin temperature and capillary refill (CR) time in forehead, sternum and finger pulp.

    Methods

    An observational, nonrandomized experimental study on 15 healthy subjects (6 females) in a cold room (8°C). Outcome measures were skin temperature and quantified CR test after application of a standardized blanching pressure (9 N/cm2) using digital photographic polarization spectroscopy to generate CR times.

    Results

    The finger pulp showed marked temperature fall and prolonged CR times (>10 seconds). The CR registrations of the forehead and sternum were more comparable to curves observed in a control material at room temperature, and skin temperature falls were less marked. CR times were not prolonged in forehead measurements. At the sternum, some individuals showed CR times beyond guideline recommendations despite only a marginal reduction in skin temperature.

    Conclusions

    Low ambient temperature is a strong independent factor for CR time at peripheral sites. Reservation about sternum as a site of measurement is warranted since cold provocation produced prolonged CR times in some individuals. We found that the forehead is the most thermostable of the 3 sites and thus the preferred site to avoid ambient temperature artifact in measuring CR time.

    Place, publisher, year, edition, pages
    Wiley-VCH Verlagsgesellschaft, 2018
    National Category
    Atom and Molecular Physics and Optics
    Research subject
    Disaster Medicine
    Identifiers
    urn:nbn:se:liu:diva-145527 (URN)10.1002/jbio.201700371 (DOI)000434641700017 ()29384267 (PubMedID)
    Note

    Funding agencies: Socialstyrelsen; Region Ostergotland

    Available from: 2018-03-05 Created: 2018-03-05 Last updated: 2020-04-01Bibliographically approved
  • Karabag, Solmaz Filiz
    Linköping University, Department of Management and Engineering, Project Innovations and Entrepreneurship.
    An Unprecedented Global Crisis! The Global, Regional, National, Political, Economic and Commercial Impact of the Coronavirus Pandemic2020In: Journal of Applied Economics and Business Research, E-ISSN 1927-033X, Vol. 10, no 1, p. 1-6Article in journal (Refereed)
    Abstract [en]

    The proliferation of the coronavirus has created a global, regional, national, political, societal, economic and commercial crisis. The coronavirus crisis not only can be characterized as a disruptive period of instability, uncertainty, and danger but also can be perceived as a period of accelerated diffusion of digital technologies, micro-level initiatives, and a consideration of established resource-intensive forms. This paper discusses the possible impact of coronavirus pandemic crisis in the short and long term and call for research in many social and technical science fields such as political science, economics, business, management and technology management. By this paper, I intend to foster an exchange of theoretical ideas and empirical research across these topics at JAEBR and other leading journals.  

  • Atkins, Hannah
    Linköping University, Department of Social and Welfare Studies.
    Healthy Enough to Enter?: Exploring the nexus of the body and the border through South African visa medical requirements2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Visitors to South Africa wishing to stay in the country for longer than three months are required to submit a medical report which makes room for a host of physical and mental “defects”, including leprosy, venereal disease, trachoma, disabilities and mental health disorders ranging from addictions to epilepsy. The form appears to be an object that points to a multiplicity of interpretations as well as inconsistencies. It is a piece of paper encountered by several actors key to the immigration process – policy makers, visa applicants, doctors and lawyers – and through its use, showcases the tensions that exist between these sites. Furthermore, as a mandatory visa document, the medical form directs us to examine the relationship between the individual body and the exercise of state power.

  • Lee Lindgren, Ylva
    Linköping University, Department of Behavioural Sciences and Learning, Education and Sociology.
    Att interagera med en robot: En förstudie om förhållandet mellan den moderna människan och högteknologi2019Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Högteknologin i samhället idag är ständigt närvarande. Teknologiska system som lagrar information som nyttjas till individanpassad reklam och automatiserar flygplan som idag kan drivas utan medverkan av en pilot. En artificiell intelligens som hovrar i automatiska samtals- och chattrobotar och effektiviserar en mängd yrkesfält med automatiserade lösningar. Syftet med denna studie ligger i människans föreställning om mötet och interaktionen med högteknologi. Etiskt-, emotionellt-, praktiskt- och relationsmässigt har undersökningen sökt sig till en förståelse för individers förhållningssätt till fenomenet. Det har genomförts en kvalitativ innehållsanalys på åtta respondenter och det erhållna datamaterialet har tolkats med utvalda sociologiska teorier hos Marx, Weber, Bauman, Foucault, Ottomeyer och Ritzer.  Resultatet från studien visar på att det finns en skeptism och motvilja till den teknologiska utvecklingen och upplevelser av exponering och övervakning. Utifrån empirin har egna vidareutvecklingar i anslutning till den sociologiska teorin kläckts: Det allseende ögat, den ensidiga relationen samt interaktion mellan bortvända ryggar.  

  • Nuñez, Alberto
    Linköping University, Department of Computer and Information Science, Human-Centered systems.
    Human–computer interaction in second language word acquisition: A qualitative study on Peruvians’ use of computers to learn new words in Swedish2018Independent thesis Basic level (degree of Bachelor), 12 credits / 18 HE creditsStudent thesis
    Abstract [en]

    The program for language learning Svenska för invandrare (Swedish for newcomers) has only a small amount of students who complete the program successfully. The use of computers could help students and educators increase the amount of success. A review of the research on second language word acquisition in human–computer interaction suggests that there is lack of studies, especially qualitative ones, in the area. For this reason, the following pilot study explores the possibilities of using audio-visual recordings of open interviews during tasks in order to analyze human–computer interaction and discuss how it enhances or limits Swedish as a second language word acquisition. With this ambition, qualitative information about how four participants looked up the meaning of a few, selected, words on a computer was gathered through recording their interactions and comments. The results of the study are discussed from a cognitive perspective to determine which interactions enhanced, or limited, second language word acquisition. The results preliminary suggest that the use of images and dictionaries of synonyms could enhance word acquisition. However, the use of strategies to avoid writing or holding unknown words in memory, the use of online translating services, changing prefixes and suffixes to generate new queries, and the use of a search engine’s results as an information source, could limit L2 word acquisition for this particular group.

  • Härnström, Felix
    Linköping University, Department of Computer and Information Science.
    Product Line Engineering for large-scale simulators: An exploratory case study2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis takes a process-centric approach to Product Line Engineering (PLE) with the purpose of evaluating the suitability of PLE practices and processes in the context of large-scale industrial simulator products. This human-centered approach sets itself apart from previous research on the subject which has been mostly focused on architectural and technical aspects of PLE. The study took place at Saab, a Swedish aerospace and defense company whose primary product is the Saab 39 Gripen fighter aircraft. The study was conducted as a series of interviews with participants across three product lines, each responsible for a different line of simulators. By investigating their current working processes using the Family Evaluation Framework, a maturity rating was derived for each product line. This maturity rating was then considered alongside commonly reported issues and experiences in order to evaluate the usefulness of PLE practices for each product line. It was found that the studied organization could likely benefit from implementing PLE. PLE and the Family Evaluation Framework promotes practices that would alleviate some of the major issues found in the studied organization such as unclear requirements, issues with product integration and external dependencies, and a lack of quantitative data. Due to the relative immaturity of PLE processes in the studied organization, these conclusions are based on a review of existing literature and the stated goals and practices of PLE applied to the context of the studied organization.

  • Fritz, Karin
    Linköping University, Department of Electrical Engineering, Computer Vision.
    Instance Segmentation of Buildings in Satellite Images2020Independent thesis Advanced level (degree of Master (Two Years)), 300 HE creditsStudent thesis
    Abstract [en]

    When creating a photo realistic 3D model of the world using satellite imagery, image classification is an important part of the process. In this thesis the specificpart of automated building extraction is investigated. This is done by investi-gating the difference in performance between the methods instance segmentation and semantic segmentation for extraction of building footprints in orthorectified imagery. Semantic segmentation of the images is solved by using U-net, a Fully Convolutional Network that outputs a pixel-wise segmentation of the image. Instance segmentation of the images is done by a network called Mask R-CNN.The performance of the models are measured using precision, recall and the F1 score, which is the harmonic mean between precision and recall. The resulting F1 score of the two methods are similar, with U-net achieving a the F1 score of 0.684 without any post processing. Mask R-CNN achieves the F1 score of 0.676 without post processing.

  • Lidh, Josefin
    Linköping University, Department of Computer and Information Science.
    En fallstudie om vårdpersonals acceptans av en videomötestjänst2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    År 2025 ska Sverige vara bäst i världen på att utnyttja och ta tillvara på de möjligheter som finns med e-hälsa och digitalisering, enligt överenskommelsen Vision e-hälsa (SKL & Socialdepartementet, 2017). Region Östergötland är en av de regioner som strävar efter att hänga med i den digitala utvecklingen och en av satsningarna är att kunna erbjuda regionens invånare digitala vårdbesök. Pilotprojektet Digitala Vårdcentralen som pågått sedan januari 2018 gör det möjligt för patienter att via video genomföra vårdbesök med läkare och fysioterapeuter. Studien syftar till att utforska hur en framtida videomötestjänst skulle kunna utformas vad gäller dess egenskaper och behov i relation till vårdpersonal inom Region Östergötland, samt undersöka vilka faktorer som påverkar vårdpersonalens acceptans av och intention till att använda en sådan tjänst. Studien genomförs i form av en kvalitativ fallstudie och fungerar som ett första steg i utformningen av en videomötestjänst med utgångspunkt i tjänstedesign och Technology Acceptance Model (TAM). Denna studie bidrog med att föreslå ett antal egenskaper och väsentliga områden som en framtida videomötestjänst bör ta hänsyn till och sträva efter för att möta funna behov. Studiens utgångspunkt i det teoretiska ramverket TAM bidrog till ett antal påverkande faktorer för vårdpersonals acceptans av och intention till att använda vårdbesök via video. Att analysera studiens intervjudata med stöd från två förhållningssätt bidrog till en djupare förståelse för vårdpersonalen gentemot en videomötestjänst samt den komplexa kontext som de befinner sig i. Slutligen kunde studien bidra till ett antal rekommendationer för att en framtida videomötestjänst ska accepteras, vilja användas och möta vårdpersonalens behov.

  • Sandstedt, Mårten
    et al.
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Medicine and Health Sciences.
    Henriksson, Lilian
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping.
    Janzon, Magnus
    Linköping University, Department of Medical and Health Sciences, Division of Health Care Analysis. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Nyberg, Gusten
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Engvall, Jan
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    de Geer, Jakob
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping.
    Alfredsson, Joakim
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Persson, Anders
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Evaluation of an AI-based, automatic coronary artery calcium scoring software2020In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 30, no 3, p. 1671-1678Article in journal (Refereed)
    Abstract [en]

    Objectives

    To evaluate an artificial intelligence (AI)–based, automatic coronary artery calcium (CAC) scoring software, using a semi-automatic software as a reference.

    Methods

    This observational study included 315 consecutive, non-contrast-enhanced calcium scoring computed tomography (CSCT) scans. A semi-automatic and an automatic software obtained the Agatston score (AS), the volume score (VS), the mass score (MS), and the number of calcified coronary lesions. Semi-automatic and automatic analysis time were registered, including a manual double-check of the automatic results. Statistical analyses were Spearman’s rank correlation coefficient (⍴), intra-class correlation (ICC), Bland Altman plots, weighted kappa analysis (κ), and Wilcoxon signed-rank test.

    Results

    The correlation and agreement for the AS, VS, and MS were  = 0.935, 0.932, 0.934 (p < 0.001), and ICC = 0.996, 0.996, 0.991, respectively (p < 0.001). The correlation and agreement for the number of calcified lesions were  = 0.903 and ICC = 0.977 (p < 0.001), respectively. The Bland Altman mean difference and 1.96 SD upper and lower limits of agreements for the AS, VS, and MS were − 8.2 (− 115.1 to 98.2), − 7.4 (− 93.9 to 79.1), and − 3.8 (− 33.6 to 25.9), respectively. Agreement in risk category assignment was 89.5% and κ = 0.919 (p < 0.001). The median time for the semi-automatic and automatic method was 59 s (IQR 35–100) and 36 s (IQR 29–49), respectively (p < 0.001).

    Conclusions

    There was an excellent correlation and agreement between the automatic software and the semi-automatic software for three CAC scores and the number of calcified lesions. Risk category classification was accurate but showing an overestimation bias tendency. Also, the automatic method was less time-demanding.

    Key Points

    • Coronary artery calcium (CAC) scoring is an excellent candidate for artificial intelligence (AI) development in a clinical setting.

    • An AI-based, automatic software obtained CAC scores with excellent correlation and agreement compared with a conventional method but was less time-consuming.

  • Fuchs, Alexander
    et al.
    Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping. KTH, Sweden.
    Berg, Niclas
    KTH, Sweden.
    Wittberg, Lisa Prahl
    KTH, Sweden.
    Stenosis Indicators Applied to Patient-Specific Renal Arteries without and with Stenosis2019In: FLUIDS, ISSN 2311-5521, Vol. 4, no 1, article id 26Article in journal (Refereed)
    Abstract [en]

    Pulsatile flow in the abdominal aorta and the renal arteries of three patients was studied numerically. Two of the patients had renal artery stenosis. The aim of the study was to assess the use of four types of indicators for determining the risk of new stenosis after revascularization of the affected arteries. The four indicators considered include the time averaged wall shear stress (TAWSS), the oscillatory shear index (OSI), the relative reference time (RRT) and a power law model based in platelet activation modeling but applied to the endothelium, named endothelium activation indicator (EAI). The results show that the indicators can detect the existing stenosis but are less successful in the revascularized cases. The TAWSS and, more clearly, the EAI approach seem to be better in predicting the risk for stenosis relapse at the original location and close to the post-stenotic dilatation. The shortcomings of the respective indicators are discussed along with potential improvements to endothelial activation modeling and its use as an indicator for risks of restenosis.

  • Vaidyalingam Arumugam, Karthik
    Linköping University, Department of Management and Engineering, Engineering Materials.
    Effect of Process Parameters on Contour Properties in Inconel 718 Structures Fabricated by Electron Beam Melting2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Additive Manufacturing (AM), commonly known as 3D printing is a production method that utilises repeated addition of layers in order to produce a final shape. AM utilises less raw material and does not have drawbacks such as tool wear and material wastage as seen in conventional machining. However, they do have drawbacks such as poor surface and internal defects.  A common practice in AM is the fabrication of contour and bulk region using separate parameters.

     The aim of this project was to study the effects of various process parameters on the contour properties. The process parameters considered were scanning speed, beam current and focus offset. The Nickel alloy Inconel 718 was utilised in Electron Beam Melting (EBM) to fabricate the test specimen. The samples used in this project were in an as-built condition which was priorly subjected to tensile testing for a different project. The tests performed in this project are hardness testing and microstructural investigation about grains, precipitates and the various defects.

     The test results helped to understand the effect of various process parameters on the hardness and microstructure of the samples. The samples with lower scanning speed had higher hardness and lesser lack of fusion than samples with higher speed. In the case of varying beam current, the samples with higher beam current had higher hardness values and fewer lack of fusions. Similarly, the effects of varying two or more process parameters were also studied and their findings recorded. The microstructure consisted of a large number of shrinkage porosities in the bulk and contour regions. The presence of Niobium rich precipitates at grain boundaries and the grain structure for various process parameters were identified and recorded.

  • Azeez, Ahmed
    et al.
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    Eriksson, Robert
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Arts and Sciences. Linköping University, Faculty of Science & Engineering.
    Leidermark, Daniel
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    Calmunger, Mattias
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Low cycle fatigue life modelling using finite element strain range partitioning for a steam turbine rotor steel2020In: Theoretical and applied fracture mechanics (Print), ISSN 0167-8442, E-ISSN 1872-7638, Vol. 107Article in journal (Refereed)
    Abstract [en]

    Materials made for modern steam power plants are required to withstand high temperatures and flexible operational schedule. Mainly to achieve high efficiency and longer components life. Nevertheless, materials under such conditions experience crack initiations and propagations. Thus, life prediction must be made using accurate fatigue models to allow flexible operation. In this study, fully reversed isothermal low cycle fatigue tests were performed on a turbine rotor steel called FB2. The tests were done under strain control with different total strain ranges and temperatures (20 °C to 625 °C). Some tests included dwell time to calibrate the short-time creep behaviour of the material. Different fatigue life models were evaluated based on total life approach. The stress-based fatigue life model was found unusable at 600 °C, while the strain-based models in terms of total strain or inelastic strain amplitudes displayed inconsistent behaviour at 500 °C. To construct better life prediction, the inelastic strain amplitudes were separated into plastic and creep components by modelling the deformation behaviour of the material, including creep. Based on strain range partitioning approach, the fatigue life depends on different damage mechanisms at different strain ranges at 500 °C. This allows for the formulation of life curves based on either plasticity-dominated damage or creep-dominated damage. At 600 °C, creep dominated while at 500 °C creep only dominates for higher strain ranges. The deformation mechanisms at different temperatures and total strain ranges were characterised by scanning electron microscopy and by quantifying the amount of low angle grain boundaries. The quantification of low angle grain boundaries was done by electron backscatter diffraction. Microscopy revealed that specimens subjected to 600 °C showed signs of creep damage in the form of voids close to the fracture surface. In addition, the amount of low angle grain boundaries seems to decrease with the increase in temperature even though the inelastic strain amplitude was increased. The study indicates that a significant amount of the inelastic strain comes from creep strain as opposed of being all plastic strain, which need to be taken into consideration when constructing a life prediction model.

  • Karlsson, Ola
    Linköping University, Department of Management and Engineering, Machine Design.
    It’s unbelievable, feels like you’re diving: Potential benefits of Virtual Reality for  documentation and analysis in underwater archaeology2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study examined questions around the scientific validity of using digital 3D models in underwater archaeology and the potential benefits of using virtual reality (VR) as a way of working with said models for documentation and analysis. A workshop with underwater archaeologists at the Swedish National Maritime and Transport Museums was conducted and the results indicate that depending on the research question being examined, there can indeed be validity in using digital 3D models, even if they are at a somewhat lower resolution. The results furthermore indicate that VR might give a better spatial understanding and overview of a site and provide a more familiar and intuitive interface for the archaeologists when working with the digital models. Several design openings were also identified and design suggestions for features in a potential VR tool were created.

  • Erlandsson, Daniel
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Mathematics.
    Ett undersökande arbetssätt med GeoGebra som verktyg för gymnasieelevers lärande av andragradsfunktioner: En designstudie2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Undersökningar har visat att ett problem elever har med andragradsfunktioner är att de har svårt att använda begreppet för att beskriva samband mellan variabler (Grønmo & Rosén, 1997). Detta i samband med andra problem kring arbetsmomentet leder till designstudiens syfte, vilket är att utveckla undervisningsmomentet som behandlar andragradsfunktioner och relaterade begrepp kopplade till kursplanen för Matematik 2c.

    Arbetsmetoden är ett undersökande arbetssätt. Verktyget som kommer att användas är GeoGebra. Syftet uppnås genom att data samlas in från elevsvar av arbetsuppgifter och enkätfrågor och den ordinarie lärarens observationer för att få information om vad som behöver re-designas för att undervisningsmomentet ska utvecklas.

    Designstudiens förslag av re-design för undervisningsmomentet är ge elever mer tid till att genomföra lektionens utvalda uppgifter och att undervisande lärare ska ha genomgång på de moment kring arbetsområdet som eleverna hade problem med. På så vis ges möjligheten för eleverna att få feedbackpå sitt arbete. De områden kring andragradsfunktioner som eleverna hade problem med var att: tyda en konstants värde om värdet är 0 eller 1, förstå konstanten 𝑎:s påverkan på parabeln, förstå begreppet nollställen samt att de blandar ihop funktionsvärden med punkter.

    En implikation för lärarrollen är att GeoGebra med dess synkroniserade vyer är ett lämpligt verktyg att använda då elever arbetar på ett undersökande sätt. Arbetssättet är särskilt lämpat för arbetsmomentet om räta linjens ekvation.

  • Jackson, Marcus
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems.
    Design of a mechatronic locking system in a rotating gear shifter: How a knowledge-intensive approach can be utilized in a product development project2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Gear shifters are currently undergoing a shift of technology forcing companies within the industry to develop new concepts and new designs. An example of this is Kongsberg Automotive that is developing one new innovative design; a rotating gear shifter. An important part of the rotating gear shifter is the locking system that control whenever rotation (shifting of gear) should be possible.

    The purpose and objective of this thesis is to show how the design of a mechatronic locking system can be implemented in the rotating gear shifter being developed by Kongsberg Automotive to fulfill the desired function (locking the rotating gear shifter), as well as optimizing it with regards to size, cost and energy consumption. The thesis is investigating how a knowledge-intensive approach can be adopted in order to deliberately and systematically build understanding of the basic principles involved in the operation of the new technology.

    The thesis presents six different design concepts that has been studied and, based on different design aspects, they have been compared to each other. The design concept that is deemed the most suitable to the application is a locking system based on a magnetic circuit.

    The physics of the magnetic circuit has been studied and a mathematical model of the system has been derived that identifies the design parameters that affect the size, cost and energy consumption. Simulations and experiments has been performed to compare how well the theory correlate to reality.

    A mathematical model is presented which has been derived from conventional physics. The thesis also presents simulations which has been performed using state-of-the-art software. Finally, results from experiments are presented which have been conducted on prototypes of the system. All results show the same behaviour which is taken as a verification and validation of the mathematical model, motivating its continued use in further design efforts. A knowledge-intensive approach can thus be used in the development of new designs.

  • Nordström, Jan
    et al.
    Linköping University, Department of Mathematics, Computational Mathematics. Linköping University, Faculty of Science & Engineering.
    Ruggiu, Andrea Alessandro
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, Faculty of Science & Engineering.
    Eigenvalue analysis for summation-by-parts finite difference time discretizations2020In: SIAM Journal on Numerical Analysis, ISSN 0036-1429, E-ISSN 1095-7170, Vol. 58, no 2, p. 907-928Article in journal (Refereed)
    Abstract [en]

    Diagonal norm finite difference based time integration methods in summation-by-parts form are investigated. The second, fourth, and sixth order accurate discretizations are proven to have eigenvalues with strictly positive real parts. This leads to provably invertible fully discrete approximations of initial boundary value problems. Our findings also allow us to conclude that the Runge--Kutta methods based on second, fourth, and sixth order summation-by-parts finite difference time discretizations automatically satisfy previously unreported stability properties. The procedure outlined in this article can be extended to even higher order summation-by-parts approximations with repeating stencil.

  • Hooijsma, Marianne
    et al.
    University of Groningen, Groningen, the Netherlands.
    Huitsing, Gijs
    University of Groningen, Groningen, the Netherlands.
    Kisfalusi, Dorottya
    Linköping University, Department of Management and Engineering, The Institute for Analytical Sociology, IAS. Linköping University, Faculty of Arts and Sciences.
    Dijkstra, Jan Kornelis
    University of Groningen, Groningen, the Netherlands.
    Flache, Adreas
    University of Groningen, Groningen, the Netherlands.
    Veenstra, René
    University of Groningen, Groningen, the Netherlands.
    Multidimensional similarity in multiplex networks: friendships between same- and cross-gender bullies and same- and cross-gender victims2020In: Network Science, ISSN 2050-1242, Vol. 8, no 1, p. 79-96Article in journal (Refereed)
    Abstract [en]

    Similar peers are more likely to become friends, but it remains unclear how the combination of multiple characteristics, known as multidimensional similarity, influences friendships. This study aimed to investigate whether similarity in gender (attribute) and bullying or victimization (network position) contributes to friendships. The school-level networks of friendships and victim-bully relationships in 17 Dutch elementary schools (2,130 students) were examined using multiplex longitudinal social network models (RSiena). The results showed that friendships were more likely to occur between same-gender peers and between bullies sharing their targets of victimization. Multidimensional similarity (similarities in gender as well as bullying) increased the likelihood of friendships for same-gender bullies targeting the same victims, but not for same-gender victims sharing bullies. The findings underline the importance of unraveling the interplay between different dimensions of similarity for children’s relationships and surpass unidimensional similarity based on single attributes.

  • Public defence: 2020-04-23 13:15 Ada Lovelace, B-Building, LinköpingOrder onlineBuy this publication >>
    Roy, Biman
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Applications of Partial Polymorphisms in (Fine-Grained) Complexity of Constraint Satisfaction Problems2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis we study the worst-case complexity ofconstraint satisfaction problems and some of its variants. We use methods from universal algebra: in particular, algebras of total functions and partial functions that are respectively known as clones and strong partial clones. The constraint satisfactionproblem parameterized by a set of relations Γ (CSP(Γ)) is the following problem: given a set of variables restricted by a set of constraints based on the relations Γ, is there an assignment to thevariables that satisfies all constraints? We refer to the set Γ as aconstraint language. The inverse CSPproblem over Γ (Inv-CSP(Γ)) asks the opposite: given a relation R, does there exist a CSP(Γ) instance with R as its set of models? When Γ is a Boolean language, then we use the term SAT(Γ) instead of CSP(Γ) and Inv-SAT(Γ) instead of Inv-CSP(Γ).

    Fine-grained complexity is an approach in which we zoom inside a complexity class and classify theproblems in it based on their worst-case time complexities. We start by investigating the fine-grained complexity of NP-complete CSP(Γ) problems. An NP-complete CSP(Γ) problem is said to be easier than an NP-complete CSP(∆) problem if the worst-case time complexity of CSP(Γ) is not higher thanthe worst-case time complexity of CSP(∆). We first analyze the NP-complete SAT problems that are easier than monotone 1-in-3-SAT (which can be represented by SAT(R) for a certain relation R), and find out that there exists a continuum of such problems. For this, we use the connection between constraint languages and strong partial clones and exploit the fact that CSP(Γ) is easier than CSP(∆) when the strong partial clone corresponding to  Γ contains the strong partial clone of ∆. An NP-complete CSP(Γ) problem is said to be the easiest with respect to a variable domain D if it is easier than any other NP-complete CSP(∆) problem of that domain. We show that for every finite domain there exists an easiest NP-complete problem for the ultraconservative CSP(Γ) problems. An ultraconservative CSP(Γ) is a special class of CSP problems where the constraint language containsall unary relations. We additionally show that no NP-complete CSP(Γ) problem can be solved insub-exponential time (i.e. in2^o(n) time where n is the number of variables) given that theexponentialtime hypothesisis true.

    Moving to classical complexity, we show that for any Boolean constraint language Γ, Inv-SAT(Γ) is either in P or it is coNP-complete. This is a generalization of an earlier dichotomy result, which was only known to be true for ultraconservative constraint languages. We show that Inv-SAT(Γ) is coNP-complete if and only if the clone corresponding to Γ contains essentially unary functions only. For arbitrary finite domains our results are not conclusive, but we manage to prove that theinversek-coloring problem is coNP-complete for each k>2. We exploit weak bases to prove many of theseresults. A weak base of a clone C is a constraint language that corresponds to the largest strong partia clone that contains C. It is known that for many decision problems X(Γ) that are parameterized bya constraint language Γ(such as Inv-SAT), there are strong connections between the complexity of X(Γ) and weak bases. This fact can be exploited to achieve general complexity results. The Boolean domain is well-suited for this approach since we have a fairly good understanding of Boolean weak bases. In the final result of this thesis, we investigate the relationships between the weak bases in the Boolean domain based on their strong partial clones and completely classify them according to the setinclusion. To avoid a tedious case analysis, we introduce a technique that allows us to discard a largenumber of cases from further investigation.

    List of papers
    1. A Preliminary Investigation of Satisfiability Problems NotHarder than 1-in-3-SAT
    Open this publication in new window or tab >>A Preliminary Investigation of Satisfiability Problems NotHarder than 1-in-3-SAT
    2016 (English)Conference paper, Published paper (Refereed)
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:liu:diva-164152 (URN)
    Conference
    Proceedings of the 41st International Symposium on Mathematical Foundations of Computer Science (MFCS-2016)
    Available from: 2020-03-07 Created: 2020-03-07 Last updated: 2020-03-07
    2. On the Interval of Boolean Strong Partial ClonesContaining Only Projections as Total Operations
    Open this publication in new window or tab >>On the Interval of Boolean Strong Partial ClonesContaining Only Projections as Total Operations
    2017 (English)Conference paper, Published paper (Refereed)
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:liu:diva-164153 (URN)
    Conference
    47th International Symposium on Multiple-Valued Logic (ISMVL-2017)
    Available from: 2020-03-07 Created: 2020-03-07 Last updated: 2020-03-07
    3. Time Complexity of Constraint Satisfaction via Universal Algebra
    Open this publication in new window or tab >>Time Complexity of Constraint Satisfaction via Universal Algebra
    2017 (English)Conference paper, Published paper (Refereed)
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:liu:diva-164154 (URN)
    Conference
    42nd International Symposium on Mathematical Foundations of Computer Science (MFCS-2017)
    Available from: 2020-03-07 Created: 2020-03-07 Last updated: 2020-03-07
    4. A Dichotomy Theorem for the Inverse Satisfiability Problem
    Open this publication in new window or tab >>A Dichotomy Theorem for the Inverse Satisfiability Problem
    2018 (English)Conference paper, Published paper (Refereed)
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:liu:diva-164155 (URN)
    Conference
    37th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS-2017)
    Available from: 2020-03-07 Created: 2020-03-07 Last updated: 2020-03-07
    5. The Inclusion Structure of Boolean Weak Bases
    Open this publication in new window or tab >>The Inclusion Structure of Boolean Weak Bases
    2019 (English)In: 2019 IEEE 49TH INTERNATIONAL SYMPOSIUM ON MULTIPLE-VALUED LOGIC (ISMVL), IEEE , 2019, p. 31-36Conference paper, Published paper (Refereed)
    Abstract [en]

    Strong partial clones are composition closed sets of partial operations containing all partial projections, characterizable as partial polymorphisms of sets of relations Gamma (pPol(Gamma)). If C is a clone it is known that the set of all strong partial clones whose total component equals C, has a greatest element pPol(Gamma(w)), where Gamma(w) is called a weak base. Weak bases have seen applications in computer science due to their usefulness for proving complexity classifications for constraint satisfaction related problems. In this paper we completely describe the inclusion structure between pPol(Gamma(w)), pPol(Delta(w)) for all Boolean weak bases Gamma(w), and Delta(w.)

    Place, publisher, year, edition, pages
    IEEE, 2019
    Series
    International Symposium on Multiple-Valued Logic, ISSN 0195-623X
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:liu:diva-160634 (URN)10.1109/ISMVL.2019.00014 (DOI)000484992100006 ()978-1-7281-0092-0 (ISBN)
    Conference
    49th IEEE International Symposium on Multiple-Valued Logic (ISMVL)
    Available from: 2019-10-11 Created: 2019-10-11 Last updated: 2020-03-07
  • Muhrman, Karolina (Editor)
    Linköping University, Department of Behavioural Sciences and Learning, Education and Adult Learning. Linköping University, Faculty of Educational Sciences.
    Ämnesdidaktik vid Linköpings universitet2020Report (Other academic)
    Abstract [sv]

    Denna skrift ger en översikt av de ämnesdidaktiska miljöerna vid Linköpings universitet. Var och en av de ämnesdidaktiska miljöerna presenteras i ett kapitel där ämnets historia och utveckling beskrivs, hur den nuvarande forskningsfronten ser ut och var Linköpings universitet befinner sig i denna. Författarna ger exempel på pågående och genomförda forskningsprojekt samt andra aktiviteter som sker i de ämnesdidaktiska miljöerna, till exempel seminarier. De beskriver också vad det sker för samverkan och samarbeten med andra universitet, skolor, företag eller myndigheter. I varje kapitel finns kontaktuppgifter till företrädare för respektive ämnesdidaktisk miljö.

    Syftet med skriften är att ge en översiktsbild av vad ämnesdidaktik kan innebära samt den forskning och de aktiviteter som sker inom ämnesdidaktik på LiU. Skriften vänder sig både internt till medarbetare på LiU och externt till skolhuvudmän, skolledare, lärare, myndigheter osv. Genom att presentera LiU:s ämnesdidaktiska verksamheter kan vi öppna upp för samarbeten såväl internt som externt, för att utveckla den ämnesdidaktiska forskningen vidare, eller för att ge ämnesdidaktiskt stöd i olika sammanhang.

  • Axelsson, Bodil
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Culture and Society, Division of Culture, Society, Design and Media.
    ACSIS annual report 20182018Report (Other academic)
  • Axelsson, Bodil
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Culture and Society, Division of Culture, Society, Design and Media.
    ACSIS Annual Report 20172017Report (Other academic)
  • Axelsson, Bodil
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Culture and Society, Division of Culture, Society, Design and Media.
    ACSIS annual report 20162016Report (Other academic)
  • Salomonsson Olls, Anna
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Specialpedagogisk verksamhet: Möjlighet eller hinder för lärande?2008Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta arbete är en deskriptiv studie av specialpedagogers och speciallärares uppfattningar om specialpedagogisk verksamhet och deras egen roll och uppdrag med koppling till detta. Med utgångspunkt från arbetets syfte och frågeställningar formulerades enkätfrågor som besvarades av nitton specialpedagoger och speciallärare på olika skolor i en kommun. Frågorna handlade om på vilka/vilket sätt specialpedagoger och speciallärare beskriver och tolkar olika specialpedagogiska begrepp samt vilka möjligheter och hinder de anger att denna form av verksamhet kan ha för barns lärande. Resultatet visar att specialpedagogerna och speciallärarna främst ser stora möjligheter med specialpedagogisk verksamhet men också en del hinder. Möjligheterna handlar om att kunna erbjuda elever i behov av särskilt stöd samma möjlighet till lärande och utveckling som alla elever genom alternativa metoder, anpassad miljö, läromedel och hjälpmedel. Hindren som presenteras är brist på resurser, tid och möjligheter till samarbete, samverkan och samsyn. Att eleverna genom arbetssättet särskiljs, mister sin klasstillhörighet och det sociala samspelet samt betraktas och upplever sig själv som avvikande är andra viktiga faktorer.

  • Olls, Anna
    Linköping University, Department of Thematic Studies. Linköping University, Faculty of Arts and Sciences.
    Att undervisa och bedöma elever i mångkulturella klasser - problem eller möjligheter?: En studie om lärares sätt att anpassa sin verksamhet i mångkulturella klasser.2000Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    This is the product of a descriptive study about teaching in multicultural schools. With regards to my purpose and leading question, aquestionnaire was distributed and answered by 29 teachers in three schools. The questions focused teachers' opinion on an intercultural teaching and its possibilities and problems. The results show that teachers are well aware of the meaning of an intercultural teaching. They claim that they in their teaching and assessment of students with different cultural backgrounds adjust their activities regarding the students needs, in different ways. The teachers all agrees that an intercultural teaching imply problems as well as possibilities.

  • Public defence: 2020-04-24 10:15 ACAS, A-Building, LinköpingOrder onlineBuy this publication >>
    Johansson, Henrik
    Linköping University, Department of Management and Engineering, Logistics & Quality Management. Linköping University, Faculty of Science & Engineering.
    Customer Benefits in City Logistics: Towards Viable Urban Consolidation Centres2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Urban Consolidation Centre (UCC) is a city logistics initiative that has the potential to increase the efficiency of urban freight delivery systems while reducing negative environmental and social effects caused by freight vehicles. One important issue that have hindered longevity of this initiative is its viability, both the financial viability and acceptance from affected stakeholders (also called UCC customers). The UCC customers in focus in this thesis are receivers of goods and municipalities. To satisfy both types of stakeholders, their requests and, in particular, the benefits they can gain from using UCCs need to be studied. The types of benefits to be given priority differ between the stakeholders, where municipalities strive towards more societal benefits, and the main goals of receivers are an increase in efficiency and financial sustainability. In response, the purpose of this thesis is to deepen the understanding of benefits for customers of UCCs, with a particular focus on customer needs and benefits that UCCs can provide.

    This thesis consists of five appended papers, each of which uses a different methodology. The methodologies applied in the papers include a multiple interview study of five UCCs, a surveybased interview study of retail stores, and a case study of an operating UCC. Regarding customer needs, this thesis takes the customer perspective, in order to identify needs that UCCs can meet. The results presented in this thesis also highlight the importance for UCCs to give priority to meeting customer needs that stem from some type of problem. Regarding benefits that UCCs can provide, the thesis suggests how different types of benefits can be distinguished. This can give guidance to UCC operators regarding which benefits should be given priority in communication with UCC customers. However, the results highlight that it is also important to understand the situation of the customer to be able to communicate the most relevant benefits that UCCs can provide. Furthermore, the results illustrate different improvement areas that can affect the benefits for UCC customers. These identified areas are: improved understanding by both UCCs and its customers of each other’s operation, communication, developing a more holistic view for UCC customers, and developing new UCC services to match customer needs.

    The results provide a foundation for customer needs that UCCs can meet, and the benefits that UCCs can provide. This foundation can be important for UCC customers to gain a better understanding of what a UCC is and how it can affect their operation, something that this thesis contributes towards. It can also assist initiators of UCCs to determine which customer needs they should focus on. Lastly, the results and contribution also address the potential role of municipalities, and it is argued that their role should change from a more supportive role to that of a paying UCC customer. All of these aspects can increase the probability that a UCC, when established becomes viable.

    List of papers
    1. Urban consolidation centre - a literature review, categorisation, and a future research agenda
    Open this publication in new window or tab >>Urban consolidation centre - a literature review, categorisation, and a future research agenda
    2018 (English)In: International Journal of Physical Distribution & Logistics Management, ISSN 0960-0035, E-ISSN 1758-664X, Vol. 48, no 8, p. 745-764Article, review/survey (Refereed) Published
    Abstract [en]

    Purpose Urban consolidation centre (UCC) is a popular initiative targeting the challenge of negative environmental and social impacts from freight transports in cities. Despite this, UCC often fails in practice, which indicates a knowledge gap. Furthermore, research within the field can be described as fragmented, transdisciplinary and fast growing. The purpose of this paper is to provide an overview of the field by describing dominant categories and themes within the area, identify gaps in order to propose a future research agenda, and provide insights into the needs of practitioners. Design/methodology/approach A systematic literature review (SLR) targeting journal articles based on UCCs has been constructed with a supplementary snowball approach. A content analysis was performed to categorise themes in the research on UCCs and to identify research gaps, both within and outside the categories identified. Findings Despite substantial research on UCC, very little research ends up in academic journals. In all, 56 articles address UCC. The most common topics were the role of stakeholders, design of distribution structures and transport resources, environmental and social consideration, and economic considerations. Much focus is directed towards finding optimal solutions and designs for potential initiatives with very little, if any, consideration to financial viability or the management of the UCC initiative. Research limitations/implications This research points out existing gaps in the literature and proposes a future research agenda with UCCs as the focus. For example, although environmental and social arguments are often applied to justify the implementation of UCCs, few studies measure or evaluate their impact. Another important research gap is the economical consideration, both how to generate revenue and how to consider economies of scale. Practical implications The practical contribution of most studies is directed towards municipalities. Few findings are presented in a way to support companies. Additionally, by bridging the gaps related to how stakeholders can collaborate and describe what is happening in a UCC, practitioners can use such information as guidelines. Originality/value The results provide a research agenda for the fragmented research targeting UCCs, supporting the viability of future initiatives.

    Place, publisher, year, edition, pages
    EMERALD GROUP PUBLISHING LTD, 2018
    Keywords
    Content analysis; City logistics; Urban freight; Urban consolidation centre; Structural literature review
    National Category
    Business Administration
    Identifiers
    urn:nbn:se:liu:diva-151808 (URN)10.1108/IJPDLM-01-2017-0050 (DOI)000444391000002 ()
    Note

    Funding Agencies|Swedish Energy Agency

    Available from: 2018-10-04 Created: 2018-10-04 Last updated: 2020-03-20
    2. Critical factors for viable business models for urban consolidation centres
    Open this publication in new window or tab >>Critical factors for viable business models for urban consolidation centres
    2017 (English)In: Research in Transportation Economics, ISSN 0739-8859, E-ISSN 1875-7979, Vol. 64, p. 36-47Article in journal (Refereed) Published
    Abstract [en]

    Abstract Although urban consolidation centres (UCC) worldwide have improved urban freight distribution and reduced externalities, other UCC initiatives have not materialised due to problems such as for example, business model limitations. All the same, researchers have rarely described business model components relevant to city logistics. In response, the purpose of this article is to analyse critical factors for viable business models of city logistics initiatives involving UCCs. Following an extensive literature review and multiple-case study of five initiatives with UCCs, we identified seven critical factors of viable city logistics business models: the ability to scale up and down the UCC solution; an ability to continuously develop and adapt to a dynamic environment; the important entrepreneurial role of the initiator as well; the acknowledgment of society; ability to innovate new services; logistics and supply chain management competence; and the ability to take full advantage of advanced IT. All seven factors describe continuously redeveloped business models seeking to seize new and unexpected opportunities, yet also indicate that city logistics systems require local authorities and municipalities to act as initiators, enablers, and customers. The models also underscore differences between purely commercial and purely municipal city logistics initiatives.

    Place, publisher, year, edition, pages
    Elsevier, 2017
    Keywords
    Urban logistics, Business models, Critical factors, Urban consolidation centres
    National Category
    Transport Systems and Logistics
    Identifiers
    urn:nbn:se:liu:diva-144226 (URN)10.1016/j.retrec.2017.09.009 (DOI)
    Funder
    VINNOVA
    Available from: 2018-01-11 Created: 2018-01-11 Last updated: 2020-03-20
    3. Urban consolidation centres: retail stores demands for UCC services
    Open this publication in new window or tab >>Urban consolidation centres: retail stores demands for UCC services
    2017 (English)In: International Journal of Physical Distribution & Logistics Management, ISSN 0960-0035, E-ISSN 1758-664X, Vol. 47, no 7, p. 646-662Article in journal (Refereed) Published
    Abstract [en]

    Purpose - Urban consolidation centres (UCCs) are often conceived to improve services in retail stores and potentially reduce costs. However, few studies have examined how retail stores perceive the services a UCC could provide. The purpose of this paper is to explore retail stores potential demands for different services that a UCC could provide in order to foster the development and implementation of UCC solutions aimed towards more economically feasible business models. Design/methodology/approach - Structured interviews were conducted with employees at 72 retail stores. Qualitative, as well as quantitative analyses, were conducted to identify the potential demands of the retail stores. Findings - The authors have provided arguments why retail stores might be interested in UCC services, and thereby potentially pay for them. Improved customer service to stores customers might not be a valid argument. The authors point to the cost aspect: stores expend resources that a UCC could provide in a more cost-efficient manner. Research limitations/implications - The findings contradict previous studies to some extent, as it indicates that a UCC may actually not enhance customer service in retail stores. Instead, the findings point to the importance of considering the potential advantages according to economies of scale that are facilitated by UCC services. Practical implications - Taking the perspective of the stores is important in order to identify arguments for why they should pay for the services provided by a UCC. Social implications - Financially viable UCC solutions are needed in order for the initiatives to be maintained and thereby provide a long-term decrease in the environmental and social footprints caused by urban freight. Originality/value - This study answers the call for research addressing retailers perspective in urban logistics, as it takes a demand-driven perspective of the development of UCC services. Furthermore, by highlighting services requested by retail stores, it can guide the financing of UCC initiatives, an aspect that has been lacking.

    Place, publisher, year, edition, pages
    EMERALD GROUP PUBLISHING LTD, 2017
    Keywords
    Customer service; Business model; Urban freight; City logistics; Receivers; Urban consolidation centre; Urban distribution
    National Category
    Business Administration
    Identifiers
    urn:nbn:se:liu:diva-140529 (URN)10.1108/IJPDLM-02-2017-0114 (DOI)000407286000005 ()
    Conference
    Annual Nordic Logistics and SCM Researchers Conference (NOFOMA)
    Note

    Funding Agencies|VINNOVA; Swedens Innovation Agency

    Available from: 2017-09-11 Created: 2017-09-11 Last updated: 2020-03-20
    4. Designing a business model for redistribution of surplus food
    Open this publication in new window or tab >>Designing a business model for redistribution of surplus food
    2018 (English)Conference paper, Published paper (Refereed)
    National Category
    Transport Systems and Logistics
    Identifiers
    urn:nbn:se:liu:diva-148837 (URN)
    Conference
    NoFoMa 2018, Kolding, Denmark, 13-15 June, 2018
    Funder
    VINNOVA, 2017-03156
    Available from: 2018-06-20 Created: 2018-06-20 Last updated: 2020-03-20Bibliographically approved
  • Brattström, Ann
    Linköping University, Department of Behavioural Sciences and Learning.
    Nyanlända mellanstadieelever i behov av särskilt stöd i matematik: En intervjustudie om hur svenska skolor arbetar med särskilda åtgärder och vilka dilemman som stöts på2020Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When newly arrived students, who come to Sweden from the age of 9 to 12 years, have major knowledge gaps in mathematics knowledge, it is a challenge for the Swedish schools to meet these students' need for support. The purpose of this study is to deepen knowledge about how Swedish schools work with newly arrived middle school students who, due to lack of basicmathematical knowledge, need special support. The study's theoretical starting point is a dilemma perspective. The method of this study is of empirical qualitative nature where interviews with special educators and teachers are conducted. The empirical evidence is analyzed by a thematic analysis. The study concludes that special educators and teachers at the Swedish schools believe that it is a functional organizational measure that newly arrived middle school students start in a preparation class. Many different special organizational actions are being implemented at the Swedish schools to meet the needs of these students with a lack of basic mathematical basic knowledge. However, the most educators believe that the efforts are not enough at their schools. In terms of working methods, the educators agree that it is important to build up the mathematical knowledge, step by step, to use a language-developing working method, to start with laboratory material and to release the mathematics book. What is perceived as a dilemma is that students often are obliged to acquire a great deal of mathematical knowledge in a short time and that the newly arrived students do not master the language of instruction and are not familiar with Swedish culture. The success factors that educators experience are teaching in a small group, an experienced primary school teacher who teaches the students and that the students are motivated when working with mathematics.

  • Magnuson, Martin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Olovsson, Weine
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Ghafoor, Naureen
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Interface bonding of Zr1−xAlxN nanocomposites investigated by x-ray spectroscopies and first principles calculations2020In: Physical Review Research, E-ISSN 2643-1564, Vol. 2, no 1Article, book review (Refereed)
    Abstract [en]

    The electronic structure, chemical bonding, and interface component in ZrN-AlN nanocomposites formed byphase separation during thin film deposition of metastable Zr1−xAlxN (x = 0.0, 0.12, 0.26, 0.40) are investigatedby resonant inelastic x-ray scattering, x-ray emission, and x-ray absorption spectroscopy and compared to firstprinciples calculations including transitions between orbital angular momentum final states. The experimentalspectra are compared with different interface-slab model systems using first principles all-electron full-potentialcalculations where the core states are treated fully relativistically. As shown in this work, the bulk sensitivity andelement selectivity of x-ray spectroscopy enables one to probe the symmetry and orbital directions at interfacesbetween cubic and hexagonal crystals. We show how the electronic structure develops from local octahedralbond symmetry of cubic ZrN that distorts for increasing Al content into more complex bonding. This results inthree different kinds of bonding originating from semicoherent interfaces with segregated ZrN and lamellar AlNnanocrystalline precipitates. An increasing chemical shift and charge transfer between the elements takes placewith increasing Al content and affects the bond strength and increases resistivity.

  • David, Johansson
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Building maintainable web applications using React: An evaluation of architectural patterns conducted on Canvas LMS2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Maintainability for web applications is increasingly important due to increasing demands for advanced functionality as well as a short time-to-market. Fixing errors, reusing functionality and adding new features efficiently are crucial for making the application profitable for the software organization as well as valuable for the end-user. Modern frameworks and libraries such as React assist web engineers in building sophisticated applications using high-quality solutions called architectural patterns. In this thesis architectural patterns have been evaluated by performing static code analysis using well-established metrics. The evaluation was conducted using a Design Science Research approach on the Learning Management System Canvas. The results showed large variations in maintainability depending on the architectural pattern used.

  • Public defence: 2020-04-17 10:15 K3 Önnesjösalen, Kåkenhus, NorrköpingOrder onlineBuy this publication >>
    Adam, Rania Elhadi
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Synthesis and Characterization of Some Nanostructured Materials for Visible Light-driven Photo Processes2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Nanostructured materials for visible light driven photo-processes such as photodegradation of organic pollutants and photoelectrochemical (PEC) water oxidation for hydrogen production are very attractive because of the positive impact on the environment. Metal oxides-based nanostructures are widely used in these photoprocesses due to their unique properties. But single nanostructured metal oxide material might suffer from low efficiency and instability in aqueous solutions under visible light. These facts make it important to have an efficient and reliable nanocomposite for the photo-processes. The combination of different nanomaterials to form a composite configuration can produce a material with new properties. The new properties which are due to the synergetic effect, are a combination of the properties of all the counterparts of the nanocomposite. Zinc oxides (ZnO) have unique optical and electrical properties which grant it to be used in optoelectronics, sensors, solar cells, nanogenerators, and photocatalysis activities. Although ZnO absorbs visible light from the sun due to the deep level band, it mainly absorbs ultraviolet wavelengths which constitute a small portion of the whole solar spectrum range. Also, ZnO has a problem with the high recombination rate of the photogenerated electrons. These problems might reduce its applicability to the photo-process. Therefore, our aim is to develop and investigate different nanocomposites materials based on the ZnO nanostructures for the enhancement of photocatalysis processes using the visible solar light as a green source of energy. Two photo-processes were applied to examine the developed nanocomposites through photocatalysis: (1) the photodegradation of organic dyes, (2) PEC water splitting. In the first photo-process, we used the ZnO nanoparticles (NPs), Magnesium (Mg)-doped ZnO NPs, and plasmonic ZnO/graphene-based nanocomposite for the decomposition of some organic dyes that have been used in industries. For the second photo-process, ZnO photoelectrode composite with different silver-based semiconductors to enhance the performance of the ZnO photoelectrode was used for PEC reaction analysis to perform water splitting. The characterization and photocatalysis experiment results showed remarkable enhancement in the photocatalysis efficiency of the synthesized nanocomposites. The observed improved properties of the ZnO are due to the synergetic effects are caused by the addition of the other nanomaterials. Hence, the present thesis attends to the synthesis and characterization of some nanostructured materials composite with ZnO that are promising candidates for visible light-driven photo-processes.  

    List of papers
    1. Synthesis of ZnO nanoparticles by co-precipitation method for solar driven photodegradation of Congo red dye at different pH
    Open this publication in new window or tab >>Synthesis of ZnO nanoparticles by co-precipitation method for solar driven photodegradation of Congo red dye at different pH
    2018 (English)In: PHOTONICS AND NANOSTRUCTURES-FUNDAMENTALS AND APPLICATIONS, ISSN 1569-4410, Vol. 32, p. 11-18Article in journal (Refereed) Published
    Abstract [en]

    Solar driven photocatalytic processes to remove organic pollutants from wastewater and other aqueous solutions is very important and useful due to its environmental benefits regarding sustainability aspect. In this article, we report a study on the use of bare zinc oxide (ZnO) nanoparticles (NPs) prepared by the chemical low temperature co-precipitation method and used as a catalyst to degrade the Congo red dye from aqueous solution using solar radiation. We performed the photocatalytic experiments for degradation of Congo red dye under solar radiation at different pH values. The results showed that the ZnO NPs are effective under solar radiation for degradation of Congo red dye. Even when the pH was varied down to 4 or raised to 10, the degradation was observed to be slightly improved. This result is due to the excess of radicals species, which enhance the photocatalytic process. In general, the observed degradation efficiency of the ZnO NPs is due to the deep level defects within the band gap that were introduced during the growth process of the ZnO NPs, which enhance the absorption wavelength band towards the visible light region. Recycling of the ZnO NPs for 3 successive runs have indicated the feasibility of reusing the NPs for several times. This implies that by using bare ZnO NPs an efficient approach for degradation of toxic waste can be achieved. Radical scavengers were used to evaluate the role of the radicals in the reaction mechanism.

    Place, publisher, year, edition, pages
    ELSEVIER SCIENCE BV, 2018
    Keywords
    ZnO nanoparticles; Point defects; Photocatalytic
    National Category
    Atom and Molecular Physics and Optics
    Identifiers
    urn:nbn:se:liu:diva-153525 (URN)10.1016/j.photonics.2018.08.005 (DOI)000451653700003 ()
    Note

    Funding Agencies|department of Science and Technology, Linkoping University, Sweden

    Available from: 2018-12-20 Created: 2018-12-20 Last updated: 2020-03-18
    2. Synthesis of Mg-doped ZnO NPs via a chemical low-temperature method and investigation of the efficient photocatalytic activity for the degradation of dyes under solar light
    Open this publication in new window or tab >>Synthesis of Mg-doped ZnO NPs via a chemical low-temperature method and investigation of the efficient photocatalytic activity for the degradation of dyes under solar light
    Show others...
    2020 (English)In: Solid State Sciences, ISSN 1293-2558, E-ISSN 1873-3085, Vol. 99, article id 106053Article in journal (Refereed) Published
    Abstract [en]

    Doped semiconductors nanostructures (NSs) have shown great interest as a potential for green and efficient photocatalysis activities. Magnesium (Mg)-doped zinc oxide (ZnO) nanoparticles (NPs) has been synthesized by a one-step chemical low temperature (60 °C) co-precipitation method without further calcination and their photocatalytic performance for photodegradation of Methylene blue (MB) dye under the illumination of solar light is investigated. The crystal structure of the synthesized NPs is examined by X-ray diffraction (XRD). XRD data indicates a slight shift towards higher 2θ angle in Mg-doped samples as compared to the pure ZnO NPs which suggest the incorporation of Mg2+ into ZnO crystal lattice. X-ray photoelectron spectroscopy (XPS), UV–Vis spectrophotometer and cathodoluminescence (CL) spectroscopy, were used to study electronics, and optical properties, respectively. The XPS analysis confirms the substitution of the Zn2+ by the Mg2+ into the ZnO crystal lattice in agreement with the XRD data. The photocatalytic activities showed a significant enhancement of the Mg-doped ZnO NPs in comparison with pure ZnO NPs. Hole/radical scavengers were used to reveal the mechanism of the photodegradation. It was found that the addition of the Mg to the ZnO lattices increases the absorption of the hydroxyl ions at the surface of the NPs and hence acts as a trap site leading to decrease the electron-hole pair and consequently enhancing the photodegradation.

    Place, publisher, year, edition, pages
    Elsevier, 2020
    Keywords
    ZnO nanoparticles, Mg-doped ZnO NPs, Photocatalytic, Photodegradation, Methylene blue, Congo red
    National Category
    Materials Chemistry
    Identifiers
    urn:nbn:se:liu:diva-164333 (URN)10.1016/j.solidstatesciences.2019.106053 (DOI)000516720100024 ()2-s2.0-85074706430 (Scopus ID)
    Available from: 2020-03-18 Created: 2020-03-18 Last updated: 2020-03-24Bibliographically approved
    3. Graphene-based plasmonic nanocomposites for highly enhanced solar-driven photocatalytic activities
    Open this publication in new window or tab >>Graphene-based plasmonic nanocomposites for highly enhanced solar-driven photocatalytic activities
    Show others...
    2019 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 52, p. 30585-30598Article in journal (Refereed) Published
    Abstract [en]

    High-efficiency photocatalysts are crucial for the removal of organic pollutants and environmental sustainability. In the present work, we report on a new low-temperature hydrothermal chemical method, assisted by ultrasonication, to synthesize disruptive plasmonic ZnO/graphene/Ag/AgI nanocomposites for solar-driven photocatalysis. The plasmonic nanocomposites were investigated by a wide range of characterization techniques, confirming successful formation of photocatalysts with excellent degradation efficiency. Using Congo red as a model dye molecule, our experimental results demonstrated a photocatalytic reactivity exceeding 90% efficiency after one hour simulated solar irradiation. The significantly enhanced degradation efficiency is attributed to improved electronic properties of the nanocomposites by hybridization of the graphene and to the addition of Ag/AgI which generates a strong surface plasmon resonance effect in the metallic silver further improving the photocatalytic activity and stability under solar irradiation. Scavenger experiments suggest that superoxide and hydroxyl radicals are responsible for the photodegradation of Congo red. Our findings are important for the fundamental understanding of the photocatalytic mechanism of ZnO/graphene/Ag/AgI nanocomposites and can lead to further development of novel efficient photocatalyst materials.

    Place, publisher, year, edition, pages
    Royal Meteorological Society, 2019
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-160568 (URN)10.1039/C9RA06273D (DOI)000487989300064 ()
    Note

    Funding agencies: Department of Science and Technology (ITN) at Campus Norrkoping, Linkoping University, Sweden; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation

    Available from: 2019-09-30 Created: 2019-09-30 Last updated: 2020-03-18Bibliographically approved
    4. n–n ZnO–Ag2CrO4 heterojunction photoelectrodes with enhanced visible-light photoelectrochemical properties
    Open this publication in new window or tab >>n–n ZnO–Ag2CrO4 heterojunction photoelectrodes with enhanced visible-light photoelectrochemical properties
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    2019 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 14, p. 7992-8001Article in journal (Refereed) Published
    Abstract [en]

    In this study, ZnO nanorods (NRs) were hydrothermally grown on an Au-coated glass substrate at a relatively low temperature (90 °C), followed by the deposition of Ag2CrO4 particles via a successive ionic layer adsorption and reaction (SILAR) route. The content of the Ag2CrO4 particles on ZnO NRs was controlled by changing the number of SILAR cycles. The fabricated ZnO–Ag2CrO4 heterojunction photoelectrodes were subjected to morphological, structural, compositional, and optical property analyses; their photoelectrochemical (PEC) properties were investigated under simulated solar light illumination. The photocurrent responses confirmed that the ability of the ZnO–Ag2CrO4 heterojunction photoelectrodes to separate the photo-generated electron–hole pairs is stronger than that of bare ZnO NRs. Impressively, the maximum photocurrent density of about 2.51 mA cm−2 at 1.23 V (vs. Ag/AgCl) was measured for the prepared ZnO–Ag2CrO4 photoelectrode with 8 SILAR cycles (denoted as ZnO–Ag2CrO4-8), which exhibited about 3-fold photo-enhancement in the current density as compared to bare ZnO NRs (0.87 mA cm−2) under similar conditions. The improvement in photoactivity was attributed to the ideal band gap and high absorption coefficient of the Ag2CrO4 particles, which resulted in improved solar light absorption properties. Furthermore, an appropriate annealing treatment was proven to be an efficient process to increase the crystallinity of Ag2CrO4 particles deposited on ZnO NRs, which improved the charge transport characteristics of the ZnO–Ag2CrO4-8 photoelectrode annealed at 200 °C and increased the performance of the photoelectrode. The results achieved in the present work present new insights for designing n–n heterojunction photoelectrodes for efficient and cost-effective PEC applications and solar-to-fuel energ

    Place, publisher, year, edition, pages
    Royal Society of Chemistry, 2019
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-155657 (URN)10.1039/C9RA00639G (DOI)000462646000051 ()2-s2.0-85062919263 (Scopus ID)
    Note

    Funding agencies: University of Mohaghegh Ardabili-Iran and Linkoping University-Sweden; AForsk [17-457

    Available from: 2019-03-22 Created: 2019-03-22 Last updated: 2020-03-18Bibliographically approved
    5. ZnO/Ag/Ag2WO4 photo-electrodes with plasmonic behavior for enhanced photoelectrochemical water oxidation
    Open this publication in new window or tab >>ZnO/Ag/Ag2WO4 photo-electrodes with plasmonic behavior for enhanced photoelectrochemical water oxidation
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    2019 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 15, p. 8271-8279Article in journal (Refereed) Published
    Abstract [en]

    Ag-based compounds are excellent co-catalyst that can enhance harvesting visible light and increase photo-generated charge carrier separation owing to its surface plasmon resonance (SPR) effect in photoelectrochemical (PEC) applications. However, the PEC performance of a ZnO/Ag/Ag2WO4 heterostructure with SPR behavior has not been fully studied so far. Here we report the preparation of a ZnO/Ag/Ag2WO4 photo-electrode with SPR behavior by a low temperature hydrothermal chemical growth method followed by a successive ionic layer adsorption and reaction (SILAR) method. The properties of the prepared samples were investigated by different characterization techniques, which confirm that Ag/Ag2WO4 was deposited on the ZnO NRs. The Ag2WO4/Ag/ZnO photo-electrode showed an enhancement in PEC performance compared to bare ZnO NRs. The observed enhancement is attributed to the red shift of the optical absorption spectrum of the Ag2WO4/Ag/ZnO to the visible region (>400 nm) and to the SPR effect of surface metallic silver (Ag0) particles from the Ag/Ag2WO4 that could generate electron–hole pairs under illumination of low energy visible sun light. Finally, we proposed the PEC mechanism of the Ag2WO4/Ag/ZnO photo-electrode with an energy band structure and possible electron–hole separation and transportation in the ZnO/Ag/Ag2WO4 heterostructure with SPR effect for water oxidation. ER

    Place, publisher, year, edition, pages
    Royal Society of Chemistry, 2019
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-155655 (URN)10.1039/C8RA10141H (DOI)000461445300016 ()
    Available from: 2019-03-22 Created: 2019-03-22 Last updated: 2020-03-18Bibliographically approved
  • Public defence: 2020-04-17 09:00 Eken, Building 421, Entrance 65, LinköpingOrder onlineBuy this publication >>
    Zötterman, Johan
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Laser Speckle Contrast Imaging in Reconstructive Surgery2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Objectives

    Reconstructive surgery aims to restore function or normal appearance by reconstructing defective organs after trauma or disease. In patients undergoing reconstructive surgery, previous trauma, surgery or radiotherapy can result in compromised blood supply. This will affect the viability of the tissue and increases the risk for postoperative complications, such as ischemia and infection. It is therefore important to assess the tissue viability, both before, during and after the surgery. This can be done using different techniques that monitor the perfusion of the skin covering the affected area. In this thesis, LSCI have been evaluated for tissue monitoring in reconstructive surgery. The technique allows for a fast and noninvasive assessment of superficial tissue perfusion over a wide field. Based on previous work on the technology, we have seen clear advantages with LSCI compared to other methods, for example laser Doppler flowmetry (LDF). We have evaluated laser speckle contrast imaging (LSCI) as a tool for tissue monitoring in reconstructive surgery in four studies.

    Methods

    In study I we used a bench top model and healthy subjects to address methodological concerns subjected to the LSCI technology. We investigated the effect of motion distance and angle on the assessed perfusion value In study II we used a porcine model to compare LSCI and LDF as tools to detect partial and full venous outflow obstruction. We used both methods to assess a flap based on the cranial gluteal artery perforator with partial and complete occlusion of the vein and artery. In study III we used the same porcine model as in study II to investigate the possibility to use LSCI intraoperatively to identify flap areas with compromised circulation and thereby predict areas with a high risk of postoperative necrosis. In study IV we used LSCI for intraoperative evaluation of tissue viability during deep inferior epigastric perforator (DIEP) free flap surgery and to investigate the perfusion distribution according to the Hartrampf zones, as measured with LSCI, in relation to the selected perforator in the deep inferior epigastric perforator free flap.

    Results

    In study I we saw that tissue perfusion as measured with LSCI increases with increasing tissue motion, independent of frame rate, number of images, and tissue perfusion. Measured perfusion will decrease when images are acquired at an angle larger than 45° but distances between 15 and 40 cm do not affect the measured perfusion. In study II we observed significant decreases in perfusion during both partial and complete venous occlusion with both LSCI and LDF. However, higher variability seen with LDF, measured as % coefficient of variation. In study III a decrease in perfusion during the first 30 min after raising the flap and a perfusion value below 25 PU after 30 min was a predictor for tissue morbidity 72h after surgery. In study IV the highest perfusion values were found in zone I and higher perfusion in zone II compared to zone III, directly after the flap was raised. No remaining significant difference between zone I, II and III could be seen after anastomosis of the vessels. All flaps with a minimum perfusion <30 PU, measured after the flap was shaped and inserted, later suffered from partial flap necrosis.

    Conclusion

    LSCI is a technology that has the potential to contribute to tissue monitoring in reconstructive surgery. It has many advantages over other techniques, such as the fast acquisition time, the spatial resolution and the fact that it is completely non-invasive. However, the current system is still too bulky to be easily introduced into a clinical setting and the technology is also subject to certain drawbacks which limit its usability. It is sensitive to motion artefacts; only superficial tissue is assessed and cannot offer absolute perfusion data. If these disadvantages could be addressed, LSCI could contribute to a more accurate survey of tissue perfusion and thus better outcome in reconstructive surgery.

    List of papers
    1. Methodological concerns with laser speckle contrast imaging in clinical evaluation of microcirculation
    Open this publication in new window or tab >>Methodological concerns with laser speckle contrast imaging in clinical evaluation of microcirculation
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    2017 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 3, article id e0174703Article in journal (Refereed) Published
    Abstract [en]

    Background Laser Speckle Contrast Imaging (LSCI) is a non-invasive and fast technique for measuring microvascular blood flow that recently has found clinical use for burn assessment and evaluation of flaps. Tissue motion caused by for example breathing or patient movements may however affect the measurements in these clinical applications, as may distance between the camera and the skin and tissue curvature. Therefore, the aims of this study were to investigate the effect of frame rate, number of frames/image, movement of the tissue, measuring distance and tissue curvature on the measured perfusion. Methods Methyl nicotinate-induced vasodilation in the forearm skin was measured using LSCI during controlled motion at different speeds, using different combinations of frame rate and number of frames/image, and at varying camera angles and distances. Experiments were made on healthy volunteers and on a cloth soaked in a colloidal suspension of polystyrene microspheres. Results Measured perfusion increased with tissue motion speed. The relation was independent of the absolute perfusion in the skin and of frame rate and number of frames/image. The measured perfusion decreased with increasing angles (16% at 60, p = 0.01). Measured perfusion did not vary significantly between measurement distances from 15 to 40 cm (p = 0.77, %CV 0.9%). Conclusion Tissue motion increases and measurement angles beyond 45 decrease the measured perfusion in LSCI. These findings have to be taken into account when LSCI is used to assess moving or curved tissue surfaces, which is common in clinical applications.

    Place, publisher, year, edition, pages
    PUBLIC LIBRARY SCIENCE, 2017
    National Category
    Radiology, Nuclear Medicine and Medical Imaging
    Identifiers
    urn:nbn:se:liu:diva-137098 (URN)10.1371/journal.pone.0174703 (DOI)000399174800074 ()28358906 (PubMedID)
    Note

    Funding Agencies|ALF grants, Region Ostergotland

    Available from: 2017-05-05 Created: 2017-05-05 Last updated: 2020-03-18
    2. Monitoring of partial and full venous outflow obstruction in a porcine flap model using laser speckle contrast imaging
    Open this publication in new window or tab >>Monitoring of partial and full venous outflow obstruction in a porcine flap model using laser speckle contrast imaging
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    2016 (English)In: Journal of Plastic, Reconstructive & Aesthetic Surgery, ISSN 1748-6815, E-ISSN 1532-1959, Vol. 69, no 7, p. 936-943Article in journal (Refereed) Published
    Abstract [en]

    Background: In microsurgery, there is a demand for more reliable methods of postoperative monitoring of free flaps, especially with regard to tissue-threatening obstructions of the feeding arteries and draining veins. In this study, we evaluated laser speckle contrast imaging (LSCI) and laser Doppler flowmetry (LDF) to assess their possibilities to detect partial and full venous outflow obstruction, as well as full arterial occlusion, in a porcine flap model. Methods: Cranial gluteal artery perforator flaps (CGAPs) were raised, and arterial and venous blood flow to and from the flaps was monitored using ultrasonic flow probes. The venous flow was altered with an inflatable cuff to simulate partial and full (50% and 100%) venous obstruction, and arterial flow was completely obstructed using clamps. The flap microcirculation was monitored using LSCI and LDF. Results: Both LDF and the LSCI detected significant changes in flap perfusion. After partial (50%) venous occlusion, perfusion decreased from baseline, LSCI: 63.5 +/- 12.9 PU (p = 0.01), LDF 31.3 +/- 15.7 (p = 0.64). After 100% venous occlusion, a further decrease in perfusion was observed: LSCI 54.6 +/- 14.2 PU (p amp;lt; 0.001) and LDF 16.7 +/- 12.8 PU (p amp;lt; 0.001). After release of the venous cuff, LSCI detected a return of the perfusion to a level slightly, but not significantly, below the baseline level 70.1 +/- 11.5 PU (p=0.39), while the LDF signal returned to a level not significant from the baseline 36.1 +/- 17.9 PU (p amp;gt; 0.99). Perfusion during 100% arterial occlusion decreased significantly as measured with both methods, LSCI: 48.3 +/- 7.7 (PU, pamp;lt;0.001) and LDF: 8.5 +/- 4.0 PU (pamp;lt;0.001). During 50% and 100% venous occlusion, LSCI showed a 20% and 26% inter-subject variability (CV%), respectively, compared to 50% and 77% for LDF. Conclusions: LSCI offers sensitive and reproducible measurements of flap microcirculation and seems more reliable in detecting decreases in blood perfusion caused by venous obstruction. It also allows for perfusion measurements in a relatively large area of flap tissue. This may be useful in identifying areas of the flap with compromised microcirculation during and after surgery. (C) 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

    Place, publisher, year, edition, pages
    ELSEVIER SCI LTD, 2016
    Keywords
    Free flaps; Venous occlusion; Arterial occlusion; Laser Doppler; Laser speckle contrast imaging
    National Category
    Surgery
    Identifiers
    urn:nbn:se:liu:diva-130059 (URN)10.1016/j.bjps.2016.02.015 (DOI)000377698600010 ()27026039 (PubMedID)
    Note

    Funding Agencies|county of Ostergotland

    Available from: 2016-07-06 Created: 2016-07-06 Last updated: 2020-03-18
    3. The use of laser speckle contrast imaging to predict flap necrosis: An experimental study in a porcine flap model
    Open this publication in new window or tab >>The use of laser speckle contrast imaging to predict flap necrosis: An experimental study in a porcine flap model
    2019 (English)In: Journal of Plastic, Reconstructive & Aesthetic Surgery, ISSN 1748-6815, E-ISSN 1532-1959, Vol. 72, no 5, p. 771-777Article in journal (Refereed) Published
    Abstract [en]

    Background: We evaluated the use of laser speckle contrast imaging (LSCI) in the perioperative planning in reconstructive flap surgery. The aim of the study was to investigate whether LSCI can predict regions with a high risk of developing postoperative necrosis. Our hypothesis was that, perioperatively, such regions have perfusion values below a threshold value and show a negative perfusion trend. Methods: A porcine flap model based on the cranial gluteal artery perforator was used. Images were acquired before surgery, immediately after surgery (t = 0), after 30 min (t =30 min), and after 72h (t = 72 h). Regions of interest (ROIs) were chosen along the central axis of the flap. Clinical evaluation of the flap was made during each time point. Results: At t = 72 h, a demarcation line could be seen at a distance of 15.8 +/- 0.4 cm away from the proximal border of the flaps. At t =0, perfusion decreased gradually from the proximal to the distal ROI. At t =30 min, perfusion was significantly lower in the ROI distal to the final demarcation line than that at t = 0, and in all flaps, these ROIs had a perfusion amp;lt;25 PU. At t= 72 h, perfusion in the ROI proximal to this line returned to baseline levels, whereas perfusion in the distal ROI remained low. Conclusions: In our model, a decrease in perfusion during the first 30 min after surgery and a perfusion amp;lt;25 PU at t = 30 min was a predictor for tissue morbidity 72 h after surgery, which indicates that LSCI is a promising technique for perioperative monitoring in reconstructive flap surgery. (C) 2018 Published by Elsevier Ltd on behalf of British Association of Plastic, Reconstructive and Aesthetic Surgeons.

    Place, publisher, year, edition, pages
    ELSEVIER SCI LTD, 2019
    Keywords
    Flap monitoring; Reconstructive surgery; Laser speckle contrast imaging; Partial flap necrosis
    National Category
    Surgery
    Identifiers
    urn:nbn:se:liu:diva-156911 (URN)10.1016/j.bjps.2018.11.021 (DOI)000464986400009 ()30711464 (PubMedID)
    Note

    Funding Agencies|County of Ostergotland

    Available from: 2019-05-28 Created: 2019-05-28 Last updated: 2020-03-18
    4. Intraoperative Laser Speckle Contrast Imaging in DIEP Breast Reconstruction: A Prospective Case Series Study
    Open this publication in new window or tab >>Intraoperative Laser Speckle Contrast Imaging in DIEP Breast Reconstruction: A Prospective Case Series Study
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    2020 (English)In: Plastic and reconstructive surgery. Global open, ISSN 2169-7574, Vol. 8, no 1, p. e2529-e2529Article in journal (Refereed) Published
    Abstract [en]

    Laser speckle contrast imaging (LSCI) is a laser-based perfusion imaging technique that recently has been shown to predict ischemic necrosis in an experimental flap model and predicting healing time of scald burns. The aims were to investigate perfusion in relation to the selected perforator during deep inferior epigastric artery perforator (DIEP) flap surgery, and to evaluate LSCI in assisting of prediction of postoperative complications. METHODS: Twenty-three patients who underwent DIEP-procedures for breast reconstruction at 2 centers were included. Perfusion was measured in 4 zones at baseline, after raising, after anastomosis, and after shaping the flap. The perfusion in relation to the selected perforator and the accuracy of LSCI in predicting complications were analyzed. RESULTS: After raising the flap, zone I showed the highest perfusion (65 ± 10 perfusion units, PU), followed by zone II (58 ± 12 PU), zone III (53 ± 10 PU), and zone IV (45 ± 10 PU). The perfusion in zone I was higher than zone III (P = 0.002) and zone IV (P < 0.001). After anastomosis, zone IV had lower perfusion than zone I (P < 0.001), zone II (P = 0.01), and zone III (P = 0.02). Flaps with areas <30 PU after surgery had partial necrosis postoperatively (n = 4). CONCLUSIONS: Perfusion is highest in zone I. No perfusion difference was found between zones II and III. Perfusion <30 PU after surgery was correlated with partial necrosis. LSCI is a promising tool for measurement of flap perfusion and assessment of risk of postoperative ischemic complications.

    Place, publisher, year, edition, pages
    Wolters Kluwer, 2020
    National Category
    Surgery
    Identifiers
    urn:nbn:se:liu:diva-164324 (URN)10.1097/GOX.0000000000002529 (DOI)32095386 (PubMedID)
    Note

    32095386[pmid]; PMC7015619[pmcid]

    Available from: 2020-03-17 Created: 2020-03-17 Last updated: 2020-03-23Bibliographically approved
  • Public defence: 2020-04-24 10:15 Planck, F Building, LinköpingOrder onlineBuy this publication >>
    Jönsson, Johan
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Electronic transitions and correlation effects: From pure elements to complex materials2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Macroscopic properties of real materials, such as conductivity, magneticproperties, crystal structure parameters, etc. are closely related or evendetermined by the configuration of their electrons, characterized by electronicstructure. By changing the conditions, e.g, pressure, temperature, magnetic/electric field, chemical doping, etc. one can modify the electronic structure ofsolids and therefore induce a phase transition(s) between different electronic andmagnetic states. One famous example is a Mott metal-to-insulator phase transition,at which a material undergoes a significant, often many orders of magnitude, changeof conductivity caused by the interplay between itineracy and localization of thecarriers.

    Electronic topological transitions (ETT) involvechanges in the topology of a metal's Fermi surface. This thesis investigates theeffect of such electronic transitions in various materials, ranging from pureelements to complex compounds.

    To describe the interplay between electronic transitionsand properties of real materials,different state-of-the-art computational methods are used. The densityfunctional theory(DFT), as well as the DFT + U method, is used to calculatestructural properties. The validity of recently introduced exchange-correlationfunctionals, such as the strongly constrained and appropriately normed (SCAN)functional, is also assessed for magnetic elements. In order toinclude dynamical effects of electron interactions we use the DFT + dynamical meanfield theory (DFT + DMFT) method.

    Experiments in hcp-Os have reported peculiarities in the ratio betweenlattice parameters at high pressure. Previous calculations have suggested these transitions maybe related to ETTs and even crossings of core levels at ultra high pressure. Inthis thesis it is shownthat the crossing of core levels is a general feature of heavy transitionmetals. Experiments have therefore been performed to look for indications ofthis transition in Ir using X-ray absorption spectroscopy. In NiO, strongrepulsion between electrons leads to a Mott insulating state at ambientconditions. It has long been predicted that high pressure will lead to aninsulator-to-metal transition. This has been suggested to be accompanied by aloss of magnetic order, and a structural phase transition. In collaboration withexperimentalists we look for thistransition by investigating the X-ray absorption spectra as well as themagnetic hyperfine field. We find no evidence of a Mott transition up to 280GPa. In the Mott insulator TiPO4, application of external pressure has beensuggested to lead to a spin-Peierls transition at room temperature. Weinvestigate the dimerisation and the magnetic structure of TiPO4 at high pressure.As pressure is increased further, TiPO4 goes through a metal to insulatortransition before an eventual crystallographic phase transition. Remarkably, thenew high pressure phases are found to be insulators; the Mott insulating stateis restored.

    MAX phases are layered materials that combinemetallic and ceramic properties and feature layers of M-metal and X-C or N atomsinterconnected by A-group atoms. Magnetic MAX-phases with their low dimensionalmagnetism are promising candidates for applications in e.g., spintronics.The validity of various theoretical approaches are discussed in connection tothe magnetic MAX-phase Mn2GaC. Using DFT and DFT + DMFT we consider the hightemperature paramagnetic state, and whether the magnetic moments are formed bylocalized or itinerant electrons.

    List of papers
    1. Assessing the SCAN functional for itinerant electron ferromagnets
    Open this publication in new window or tab >>Assessing the SCAN functional for itinerant electron ferromagnets
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    2018 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 98, no 9, article id 094413Article in journal (Refereed) Published
    Abstract [en]

    Density functional theory is a standard model for condensed-matter theory and computational material science. The accuracy of density functional theory is limited by the accuracy of the employed approximation to the exchange-correlation functional. Recently, the so-called strongly constrained appropriately normed (SCAN) [Sun, Ruzsinszky, and Perdew, Phys. Rev. Lett. 115, 036402 (2015)] functional has received a lot of attention due to promising results for covalent, metallic, ionic, as well as hydrogen- and van der Waals-bonded systems alike. In this work, we focus on assessing the performance of the SCAN functional for itinerant magnets by calculating basic structural and magnetic properties of the transition metals Fe, Co, and Ni. We find that although structural properties of bcc-Fe seem to be in good agreement with experiment, SCAN performs worse than standard local and semilocal functionals for fcc-Ni and hcp-Co. In all three cases, the magnetic moment is significantly overestimated by SCAN, and the 3d states are shifted to lower energies, as compared to experiments.

    Place, publisher, year, edition, pages
    AMER PHYSICAL SOC, 2018
    National Category
    Theoretical Chemistry
    Identifiers
    urn:nbn:se:liu:diva-151640 (URN)10.1103/PhysRevB.98.094413 (DOI)000444348500004 ()
    Note

    Funding Agencies|Swedish e-Science Research Centre (SeRC); Swedish Research Council (VR) through the International Career Grant [20146336]; Marie Sklodowska CurieActions, Cofund, Project [INCA 600398]; Swedish Foundation for Strategic Research (SSF) through the Future Research Leaders 6 program; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; competence center FunMat-II - Vinnova [201605156]; Russian Science Foundation [18-12-00492]

    Available from: 2018-09-27 Created: 2018-09-27 Last updated: 2020-03-17
    2. Pressure-induced crossing of the core levels in 5d metals
    Open this publication in new window or tab >>Pressure-induced crossing of the core levels in 5d metals
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    2016 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 93, no 20, p. 205150-Article in journal (Refereed) Published
    Abstract [en]

    A pressure-induced interaction between core electrons, the core-level crossing (CLC) transition, has been observed in hcp Os at P approximate to 400 GPa [L. Dubrovinsky et al., Nature (London) 525, 226 (2015)]. By carrying out a systematic theoretical study for all metals of the 5d series (Hf, Ta, W, Re, Os, Ir, Pt, Au) we have found that the CLC transition is a general effect for this series of metals. While in Pt it occurs at approximate to 1500 GPa, at a pressure substantially higher than in Os, in Ir it occurs already at 80 GPa. Moreover, we predict that in Re the CLC transition may take place already at ambient pressure. We explain the effect of the CLC and analyze the shift of the transition pressure across the series within the Thomas-Fermi model. In particular, we show that the effect has many common features with the atomic collapse in rare-earth elements.

    Place, publisher, year, edition, pages
    AMER PHYSICAL SOC, 2016
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-129490 (URN)10.1103/PhysRevB.93.205150 (DOI)000376638700004 ()
    Note

    Funding Agencies|Swedish Government Strategic Research Area Grant Swedish e-Science Research Centre (SeRC); Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of MISiS; Swedish Foundation for Strategic Research (SSF) program SRL [10-0026]; Swedish Research Council (VR) [2015-04391]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; German Research Foundation (DFG); Federal Ministry of Education and Research (BMBF), Germany; DFG [DU 954-8/1]; BMBF (PT-DESY) [5K13WC3, O5K2013, 2]; Act 211 Government of the Russian Federation [02.A03.21.0006]; Knut and Alice Wallenberg Foundation [2012.0083, 2014-2019]

    Available from: 2016-06-21 Created: 2016-06-20 Last updated: 2020-03-17
    3. Topological transitions of the Fermi surface of osmium under pressure: an LDA plus DMFT study
    Open this publication in new window or tab >>Topological transitions of the Fermi surface of osmium under pressure: an LDA plus DMFT study
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    2017 (English)In: New Journal of Physics, ISSN 1367-2630, E-ISSN 1367-2630, Vol. 19, article id 033020Article in journal (Refereed) Published
    Abstract [en]

    The influence of pressure on the electronic structure of Os has attracted substantial attention recently due to reports on isostructural electronic transitions in this metal. Here, we theoretically investigate the Fermi surface of Os from ambient to high pressure, using density functional theory combined with dynamical mean field theory. Weprovide a detailed discussion of the calculated Fermi surface and its dependence on the level of theory used for the treatment of the electron-electron interactions. Although we confirm that Os can be classified as weakly correlated metal, the inclusion of local quantum fluctuations between 5d electrons beyond the local density approximation explains the most recent experimental reports regarding the occurrence of electronic topological transitions in Os.

    Place, publisher, year, edition, pages
    IOP PUBLISHING LTD, 2017
    Keywords
    electronic topological transitions; strong correlations; Fermi surfaces
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-136604 (URN)10.1088/1367-2630/aa5f8e (DOI)000398666100004 ()
    Note

    Funding Agencies|Swedish Foundation for Strategic Research SSF (SRL) [10-0026]; Swedish Research Council (VR) grant [2015-04391]; Knut and Alice Wallenberg Foundation [2014-2019]; Swedish Government Strategic Research Area SeRC; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFOMatLiU) [2009 00971]; Ministry of Education and Science of the Russian Federation of NUST MISIS [K2-2016-013]; PHD DALEN Project [26228RM]; Swedish National Infrastructure for Computing (SNIC)

    Available from: 2017-04-21 Created: 2017-04-21 Last updated: 2020-03-17
    4. Phase stability and electronic structure of iridium metal at the megabar range
    Open this publication in new window or tab >>Phase stability and electronic structure of iridium metal at the megabar range
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    2019 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 8940Article in journal (Refereed) Published
    Abstract [en]

    The 5d transition metals have attracted specific interest for high-pressure studies due to their extraordinary stability and intriguing electronic properties. In particular, iridium metal has been proposed to exhibit a recently discovered pressure-induced electronic transition, the so-called core-level crossing transition at the lowest pressure among all the 5d transition metals. Here, we report an experimental structural characterization of iridium by x-ray probes sensitive to both long- and short-range order in matter. Synchrotron-based powder x-ray diffraction results highlight a large stability range (up to 1.4 Mbar) of the low-pressure phase. The compressibility behaviour was characterized by an accurate determination of the pressure-volume equation of state, with a bulk modulus of 339(3) GPa and its derivative of 5.3(1). X-ray absorption spectroscopy, which probes the local structure and the empty density of electronic states above the Fermi level, was also utilized. The remarkable agreement observed between experimental and calculated spectra validates the reliability of theoretical predictions of the pressure dependence of the electronic structure of iridium in the studied interval of compressions.

    Place, publisher, year, edition, pages
    Nature Publishing Group, 2019
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-158862 (URN)10.1038/s41598-019-45401-x (DOI)000472137700036 ()31222067 (PubMedID)2-s2.0-85067628529 (Scopus ID)
    Note

    Funding Agencies|Spanish Ministry of Science, Innovation and Universities; Spanish Research Agency (AEI); European Fund for Regional Development (FEDER) [MAT2016-75586-C4-1/2-P]; Generalitat Valenciana [Prometeo/2018/123]; Spanish Mineco Project [FIS2017-83295-P]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]; Ministry of Science and High Education of the Russian Federation [K2-2019-001]; "Juan de la Cierva" fellowship [FJCI-2016-27921]; "Ramon y Cajal" fellowship [RYC-2015-17482]

    Available from: 2019-07-16 Created: 2019-07-16 Last updated: 2020-03-19Bibliographically approved
    5. Magnetic interactions in NiO at ultrahigh pressure
    Open this publication in new window or tab >>Magnetic interactions in NiO at ultrahigh pressure
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    2016 (English)In: PHYSICAL REVIEW B, ISSN 2469-9950, Vol. 93, no 20, p. 201110-Article in journal (Refereed) Published
    Abstract [en]

    Magnetic properties of NiO have been studied in the multimegabar pressure range by nuclear forward scattering of synchrotron radiation using the 67.4 keV Mossbauer transition of Ni-61. The observed magnetic hyperfine splitting confirms the antiferromagnetic state of NiO up to 280 GPa, the highest pressure where magnetism has been observed so far, in any material. Remarkably, the hyperfine field increases from 8.47 T at ambient pressure to similar to 24 T at the highest pressure, ruling out the possibility of a magnetic collapse. A joint x-ray diffraction and extended x-ray-absorption fine structure investigation reveals that NiO remains in a distorted sodium chloride structure in the entire studied pressure range. Ab initio calculations support the experimental observations, and further indicate a complete absence of Mott transition in NiO up to at least 280 GPa.

    Place, publisher, year, edition, pages
    AMER PHYSICAL SOC, 2016
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-129492 (URN)10.1103/PhysRevB.93.201110 (DOI)000376638400001 ()
    Note

    Funding Agencies|National Science Foundation-Earth Sciences [EAR-1128799]; Department of Energy-GeoSciences [DE-FG02-94ER14466]; DOE Office of Science [DE-AC02-06CH11357]; Helmholtz Association; Materials Sciences and Engineering Division, Office of Basic Energy Sciences, U.S. Department of Energy; Swedish Government Strategic Research Area Grants Swedish e-Science Research Center (SeRC) and in Materials Science on Functional Materials at Linkoping University [2009 00971]; Knut and Alice Wallenbergs Foundation project Strong Field Physics and New States of Matter; Swedish Foundation for Strategic Research program SRL Grant [10-0026]; Swedish Research Council (VR) [2015-04391]; Grant of Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]; Tomsk State University Academic D.I. Mendeleev Fund Program

    Available from: 2016-06-20 Created: 2016-06-20 Last updated: 2020-03-17
    6. Inverse pressure-induced Mott transition in TiPO4
    Open this publication in new window or tab >>Inverse pressure-induced Mott transition in TiPO4
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    2019 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 99, no 24, article id 245132Article in journal (Refereed) Published
    Abstract [en]

    TiPO4 shows interesting structural and magnetic properties as temperature and pressure are varied, such as a spin-Peierls phase transition and the development of incommensurate modulations of the lattice. Recently, high-pressure experiments for TiPO4 reported two structural phases appearing at high pressures, the so-called phases IV and V [M. Bykov et al., Angew. Chem. Int. Ed. 55, 15053 (2016).]. The latter was shown to include the first example of fivefold O-coordinated P atoms in an inorganic phosphate compound. In this work, we characterize the electronic structure and other physical properties of these phases by means of ab initio calculations and investigate the structural transition. We find that the appearance of phases IV and V coincides with a collapse of the Mott insulating gap and quenching of magnetism in phase III as pressure is applied. Remarkably, our calculations show that in the high-pressure phase V, these features reappear, leading to an antiferromagnetic Mott insulating phase, with robust local moments.

    Place, publisher, year, edition, pages
    AMER PHYSICAL SOC, 2019
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-158863 (URN)10.1103/PhysRevB.99.245132 (DOI)000471984200002 ()
    Note

    Funding Agencies|Knut and Alice Wallenberg Foundation [KAW-2013.0020]; Swedish e-Science Research Centre (SeRC); Swedish Research Council (VR) [2015-04391]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Russian Science Foundation [18-12-00492]

    Available from: 2019-07-16 Created: 2019-07-16 Last updated: 2020-03-17
  • Fagerblom, Freja
    Linköping University, Department of Electrical Engineering, Computer Vision.
    Model-Agnostic Meta-Learning for Digital Pathology2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The performance of conventional deep neural networks tends to degrade when a domain shift is introduced, such as collecting data from a new site. Model-Agnostic Meta-Learning, or MAML, has achieved state-of-the-art performance in few-shot learning by finding initial parameters that adapt easily for new tasks.

    This thesis studies MAML in a digital pathology setting. Experiments show that a conventional model generalises poorly to data collected from another site. By annotating a few samples during inference however, a model with initial parameters obtained through MAML training can adapt to achieve better generalisation performance. It is also demonstrated that a simple transfer learning approach using a kNN classifier on features extracted from a conventional model yields good generalisation, but the variance caused by random sampling is higher.

    The results indicate that meta learning can lead to a lower annotation effort for machine learning in digital pathology while maintaining accuracy.

  • Hu, Yi
    Linköping University, Department of Computer and Information Science. Linköping University, Faculty of Science & Engineering.
    A Framework for Using Deep Learning to Detect Software Vulnerabilities2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In recent years, with the rise of Internet technology, software vulnerabilities have also flooded, making the software security of enterprises or individuals seriously threatened. Although it is difficult to avoid the occurrence of software vulnerabilities in the process of software development, it is also a way to find and modify the vulnerabilities as early as possible. At present, research on static vulnerability detection system can be divided into methods based on code similarity and pattern-based method. The method based on code similarity is mainly used to detect vulnerabilities caused by code cloning, while the vulnerabilities caused by other reasons have high false negative. Patterns-based approaches require experts to define vulnerability characteristics manually, which leads to a waste of time and effort. Besides, since defining characteristics is a subjective task, the judgement of experts will affect the results of detection. At this point, there is an urgent need for an approach that can detect vulnerabilities for various reasons and is less dependent on experts.           

    Deep learning is a new field of machine learning research, which has received extensive attention in recent years. Its use has greatly liberated human resources, which makes us think whether deep learning can also be applied to vulnerability detection research, and whether it can also solve the problem of waste of expert resources.           

    This thesis studies a software vulnerability detection framework based on deep learning. The main research contents are as follows:           

    1. Collect the source code of four types of software vulnerabilities in C/C++ (Function Call, Array Usage, Pointer Usage and Arithmetic Expression) as the dataset of the experiment in this thesis. Extract the vulnerability syntax characteristics of four kinds of software vulnerabilities, match the dataset with the vulnerability syntax characteristics, and generate syntax-based code fragments. Program slices for syntax-based code fragments are then generated and converted into semantic-based code fragments.            

    2. Data processing for semantic-based code fragments includes: replacing all strings in semantic-based code fragments with a unified string. And perform word segmentation on semantic-based code fragments. Then replace all user-defined variables in semantic-based code fragments and user-defined function names. Finally, the processed semantic-based code fragments are converted into vector representations.           

    3. According to the characteristics of software vulnerabilities, select deep learning methods suitable for text analysis: Long Short-Term Memory, Bi-directional Long Short-Term Memory, Gate Recurrent Unit, Bi-directional Gate Recurrent Unit. The four deep learning methods are designed and implemented to make the accuracy of software vulnerability detection as high as possible.            

    4. Select reasonable measurement methods to evaluate the framework, and compare it with other tools for detecting software vulnerabilities, to judge the effectiveness of the framework. 

  • Strömbäck, Filip
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Mannila, Linda
    Linköping University, Department of Computer and Information Science, Artificial Intelligence and Integrated Computer Systems. Linköping University, Faculty of Science & Engineering.
    Kamkar, Mariam
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Exploring Students’ Understanding of Concurrency: A Phenomenographic Study2020In: Proceedings of SIGCSE ’20, ACM Publications, 2020Conference paper (Refereed)
    Abstract [en]

    This paper continues previous efforts in understanding the problemsstudents face when learning concurrency. In this paper, weexplore students’ understanding of the subject using phenomenographyin order to gain insights that can aid in explaining the underlyingcauses for common student mistakes in concurrency, whichhas been studied in depth previously. Students’ experience of concurrencyand critical sections were analyzed using a phenomenographicstudy based on interviews with students attending one oftwo courses on concurrency and operating systems. We present6 categories describing students’ experience of concurrency, and4 categories describing students’ experience of critical sections inthis paper. Furthermore, these categories are related to previousresults, both to explore how misconceptions in the categores relateto student mistakes and to estimate how common it is for eachcategory to be discerned.

  • Mnich, Jagna
    et al.
    Linköping University, Department of Physics, Chemistry and Biology.
    Karlsson Björkman, Jesper
    Linköping University, Department of Physics, Chemistry and Biology.
    En överblick över det gentekniska verktyget CRISPR/CAS: Samt hur genteknikundervisningen på gymnasiet kan organiseras2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna litteraturstudie var att kartlägga hur CRISPR/Cas används inom genteknik, vilka möjligheter och risker användningen av metoden medför samt hur vi som framtida biologilärare på gymnasiet kan arbeta för att våra elever ska förskaffa sig en välbehövlig respekt och förståelse för genmodifieringens konsekvenser. 

    CRISPR/Cas (Clustered regularly interspaced short palindromic repeats/CRISPR-associated) är naturligt förekommande adaptiva immunförsvarssystem som finns hos många bakterier och arkéer. Försvarssystemet integrerar en bit av en främmande nukleinsyra i specifika CRISPR-lokus. De integrerade sekvenserna fungerar där som ett minne och gör organismen immun mot invadering av samma nukleotidsekvens. Detta genom att försvarssystemet bryter ner den igenkända invaderande nukleinsyran. CRISPR/Cas-systemen, i synnerhet CRISPR/Cas9, kan idag tillämpas för genmodifiering av olika organismer. Olika proteiner, med nukleasaktivitet, som förekommer naturligt i CRISPR/Cas-system kan användas inom genteknik för att göra dubbelsträngsbrott vid specifika sites i en organisms genom. Dubbelsträngsbrottet möjliggör vidare modifiering av nukleinsyran vid klyvningsstället.

    Trots den stora genomslagskraft som CRISPR/Cas-tekniken har haft inom flertalet områden råder det fortfarande stor osäkerhet kring gentekniken. Vilka konsekvenser kommer förändringar i människors, djurs och växters genom få i framtiden? Det är därför viktigt att skolan förser elever med kunskaper om CRISPR/Cas samt möjliggör diskussioner om etiska dilemman där genteknikens positiva effekter samt risker behandlas. Något som kan leda till att det fattas kloka och väl avvägda beslut om hur CRISPR/Cas, idag och i framtiden, ska användas för att gynna människor, djur och natur.

  • Andrésen, Lisa
    Linköping University, Department of Physics, Chemistry and Biology.
    The effect of an anti-depressant on responses to predation in an isopod2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A lot of chemicals and pharmaceutical substances used by humans, are released into the waste-water and end up in lakes and ponds. Further, because pharmaceutical substances are increasing worldwide, the problem increases. A very common human anti-depressant is fluoxetine which is found in lakes, ponds and even in the bodies of aquatic organisms. This study is focusing on how fluoxetine might change antipredation behaviour in the aquatic organism Asellus aquaticus. A. aquaticus live worldwide and are important for aquatic ecosystems because of its leaf litter decomposition degradation and hence nutrient cycling. A. aquaticus used in this study were wild-caught in lake Tåkern. In the lab, A. aquaticus were experimentally exposed to fluoxetine in an environmental relevant concentration, 20 ng/l, or kept in normal water as a control, for 28 days. After this exposure, A. aquaticus went through simulated predation attacks, and their responses were measured. I found no difference in anti-predation behaviour after the simulated predation attack in A. aquaticus, between the group exposed to fluoxetine and the control group. I found that males tended to be more active and explorative than females, but this was not affected by fluoxetine exposure. My results suggest that the dose of fluoxetine here used, did not cause behavioural changes as observed in other studies. Nevertheless, substance like fluoxetine are not the only pharmaceutical organisms in the wild are exposed to, and such cocktail effects may be additive. Future studies should therefore investigate how these substances both individually (in varying doses) and together, can affect aquatic organisms and ecosystems. 

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    Mileros, Martin Daniel
    Linköping University, Department of Management and Engineering, Project Innovations and Entrepreneurship. Linköping University, Faculty of Science & Engineering.
    Mind Your Own Business: Understanding and characterizing value created by consumers in a digital economy2020Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the context of what is commonly referred to as consumer-centric digital economy, personal data has become the new currency which is utilized by consumers to be granted access to seemingly “free apps” within so-called digital zero-price markets. Simultaneously, there are consumers, known as “content creators”, who can generate million-dollar revenues annually. The current understanding of how consumers create and capture value within this new digital economy is scarce and more research is needed to systematically build a basis for creating an understanding of value creation and capture in the consumer-centric digital economy, based on a consumer perspective. The purpose of this dissertation is consequently to explore how consumers create and capture value within a consumer-centric digital economy. The explorative study also serves to obtain an initial overview of the phenomenon and the widely dispersed literature which spans different research fields. The collected data constitute more than 500 articles in combination with empirical data collected from websites.

    Based on the current literature, central concepts related to consumer-centric digital economy are explained. These include for instance Web 2.0, user-generated content and the consumerto- business relationship. The different concepts are discussed in relation to each other and a trend analysis shows that these concepts are on the rise and have become increasingly popular.

    The results show that consumers within the digital economy may take different roles, and some create value as business-oriented consumers (i.e., consumers who have a commercial interest). For instance, they make a business out of their participation in the digital economy. Examples are YouTubers, bloggers or creators in virtual worlds such as Second Life. Another, probably larger category is characterized as traditional consumers, for instance they participate in the digital economy through their use of seemingly “free” apps but do not reap any direct monetary benefits. By sharing their personal data, they take part in value creation in a more passive way. The findings also indicate that the level of control, e.g. determined by whether or not value is created within the digital platform, may characterize the prerequisites for value capture. Based on this, a taxonomy for value creation and value capture by consumers in the digital economy is developed. The study also identifies different business model types for business-oriented consumers.

    List of papers
    1. Towards a Taxonomy of E-commerce: Characterizing Content Creator-Based Business Models
    Open this publication in new window or tab >>Towards a Taxonomy of E-commerce: Characterizing Content Creator-Based Business Models
    2019 (English)In: Technology Innovation Management Review, ISSN 1927-0321, E-ISSN 1927-0321, Vol. 9, no 10, p. 62-77Article in journal (Refereed) Published
    Abstract [en]

    Currently, new business models can be observed in content creator-based e-commerce. The research on e-commerce has grown rapidly and new concepts have emerged such as social commerce, platforms, and user-generated content. However, no overarching perspective has yet been formulated for distinguishing new content creator-based business models within e-commerce. The aim of this paper is therefore to characterize content creator-based business models by formulating a taxonomy of e-commerce based on a structured literature review of the concepts mentioned above. The results of our study point toward eight types of content creator-based business models. Our paper outlines theoretical and practical implications for the emerging phenomenon of content creator-based business, which we refer to as intellectual commerce. In addition, we describe 19 concepts related to Web 1.0, Web 2.0, and e-commerce.

    Place, publisher, year, edition, pages
    Ottawa, Canada: Carleton University, 2019
    Keywords
    Content creator-based business models, e-commerce, social commerce, consumer-to-business, multisided platforms, user-generated content, content creators, intellectual commerce, personal data, human-centered data economy
    National Category
    Business Administration
    Identifiers
    urn:nbn:se:liu:diva-161901 (URN)10.22215/timreview/1276 (DOI)
    Available from: 2019-11-12 Created: 2019-11-12 Last updated: 2020-03-16Bibliographically approved
  • Garg, Pankaj
    et al.
    Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK..
    Swift, Andrew J
    Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK.
    Zhong, Liang
    National Heart Centre Singapore, Duke-NUS Medical School, National University of Singapore, Singapore,.
    Carlhäll, Carljohan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Ebbers, Tino
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Westenberg, Jos
    Department of Radiology, Leiden University Medical Center, Leiden, Netherlands.
    Hope, Michael D
    Department of Radiology, University of California-San Francisco, San Francisco, CA, USA.
    Bucciarelli-Ducci, Chiara
    Bristol Heart Institute, Bristol National Institute of Health Research (NIHR) Biomedical Research Centre, University Hospitals Bristol NHS Trust and University of Bristol, Bristol, UK.
    Bax, Jeroen J
    Department of Cardiology, Leiden University Medical Center, Leiden, Netherlands.
    Myerson, Saul G
    Departments of Cardiology and Cardiovascular Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe Hospital, Oxford, UK.
    Assessment of mitral valve regurgitation by cardiovascular magnetic resonance imaging2019In: Nature Reviews Cardiology, ISSN 1759-5002, E-ISSN 1759-5010Article in journal (Refereed)
    Abstract [en]

    Mitral regurgitation (MR) is a common valvular heart disease and is the second most frequent indication for heart valve surgery in Western countries. Echocardiography is the recommended first-line test for the assessment of valvular heart disease, but cardiovascular magnetic resonance imaging (CMR) provides complementary information, especially for assessing MR severity and to plan the timing of intervention. As new CMR techniques for the assessment of MR have arisen, standardizing CMR protocols for research and clinical studies has become important in order to optimize diagnostic utility and support the wider use of CMR for the clinical assessment of MR. In this Consensus Statement, we provide a detailed description of the current evidence on the use of CMR for MR assessment, highlight its current clinical utility, and recommend a standardized CMR protocol and report for MR assessment.

  • Falklöf, Lennart
    Linköping University, University Services.
    LiU Magasin2020Other (Other academic)
  • Bodén, Ulrika
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Division of Learning, Aesthetics, Natural Science. Linköping University, Faculty of Educational Sciences.
    Stenliden, Linnéa
    Linköping University, Department of Behavioural Sciences and Learning, Division of Learning, Aesthetics, Natural Science. Linköping University, Faculty of Educational Sciences.
    Emerging Visual Literacy through Enactments by Visual Analytics and Students2019In: Designs for Learning, ISSN 1654-7608, Vol. 11, no 1, p. 40-51Article in journal (Refereed)
    Abstract [en]

    This paper investigates the potential aspects of visual literacy that might appear when visual analytics and students interact in social science secondary classrooms. Interacting with visual technology likely demands new forms of literacy as various dimensions of complexity emerge in such learning activities where reading imposes order and relevance on what is displayed. However, only a few studies have evaluated how these visual processes emerge. Applying a socio-material semiotic approach, this paper examines the interactions between teachers, students and a visual analytics application, clarifying what strengthens or weakens the socio-material relations at work in emerging visual literacy. Methodologically, a design-based research approach is chosen. Notably, it is the early stages of the designed-based research cycle that are applied. Interventions were designed and conducted in five classes in three secondary schools in Sweden (97 students). The visual analytics application introduced was Statistics eXplorer. For each class, two to three lessons were video recorded to capture how the students interacted with the application. The socio-material analyses show that the interactions between the visual analytics and the students were both strengthened and weakened by different social as well as material forces. The actions were directed by visual properties such as movement, highlighting, and color, properties that often resulted in quick vision or locked vision. This paper argues that there needs to be a close didactic alignment and deeper knowledge of how visual interfaces attract students’ attention and how students’ visual literacy emerges in that relationship.

  • Nordvall, Henrik (Editor)
    Linköping University, Department of Behavioural Sciences and Learning, Education and Adult Learning. Linköping University, Faculty of Educational Sciences.
    Mimerbladet Mars 20202020Other (Other academic)
  • Stenliden, Linnéa
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Division of Learning, Aesthetics, Natural Science. Linköping University, Faculty of Educational Sciences.
    Bylund, Anna
    Linköping University, Department of Behavioural Sciences and Learning, Division of Learning, Aesthetics, Natural Science. Linköping University, Faculty of Educational Sciences.
    Reimers, Eva
    Göteborgs universitet.
    Post-humanist Qualitative Data Production in Classroom Studies: A Research Machine put to Work.2018In: Reconceptualizing Educational Research Methodology (RERM), ISSN 1892-042X, E-ISSN 1892-042X, Vol. 9, no 2, p. 22-37Article in journal (Refereed)
    Abstract [en]

    This paper describes a methodological inquiry that explores ways of performing classroom studies, where posthuman theory and data production are plugged in to each other from the very outset of this effort. Posthuman theory insists on research practices that demand attention to materialities, research practices that seek to detach the investigations from human concerns and positionality, research practices that consider how data and researcher(s) are entangled producing each other and by that try to operationalize the ‘unself’ of the researcher(s). Hence, a research machine was constructed and put to work in one Physics classroom in an upper secondary school. Five researchers focused on various multiparty interactions, whilst attempting to background the interpersonal interactions. Subsequently, the research machine was plugged into different concepts and turned into workshops where changes in configurations became significant for emergences in the classroom. In this process the concept affraction emerged as an effort to map how material-semiotic processes become observable in classrooms. The work of the research machine points to possible ways of avoiding commonly privileged perspectives in classroom observations. This attempt to deconstruct boundaries between human and non-human and the human as a bounded non-porous subject may affect possibilities to produce research that aids what otherwise might be shadowed actions in classrooms.

  • Hansson, Alexander
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Psychology.
    Dehghanimongabad, Arameh
    Linköping University, Department of Behavioural Sciences and Learning, Psychology.
    Våld i nära relation: – Varför stannade hon kvar?2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Våld mot kvinnor är ett globalt samhällsproblem, där diskussionen om kvinnans roll i en våldsam relation kan leda till att skuldbelägga kvinnan för att hon stannar kvar, inte gör motstånd och inte håller den våldsutövande partnern ansvarig för våldet.  Arbetets syfte är utifrån kvalitativ metod klargöra de faktorer som kan leda till att kvinnor stannar respektive lämnar sina våldsamma partners. Forskningen angående våld i nära relationer är väldokumenterat, med Lundgrens (2012) normaliseringsprocess och exitprocessen (Holmberg & Enander, 2004) i spetsen för de specifika teorierna. Allmän teori angående våld och aggression av Anderson och Bushman (2002) beskriver att mottagare av våld svarar med liknande beteenden, vilket de specifika teorierna inte framställer. Resultatet visar att upplevelserna från informanterna drar nästan raka paralleller med normaliseringsprocessen och exitprocessen med dåligt självförtroende, beroende av den våldsamma partnern samt tvivel och motstånd som huvudtema. Informanternas upplevelser finner lite stöd från allmän teori utifrån dem själva, men kan kopplas till hur de beskriver expartnernas motivationer och beteenden.

  • Sandeberg, Chatarina
    Linköping University, Department of Behavioural Sciences and Learning.
    Bomber och sprängningar, hur förändras vårt beteende av kriminalitet?2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I denna kandidatuppsats undersökte vi beteende och emotionsförändringar i samband med sprängdådet i Linköping den 7 juni 2019. Det är en kvantitativ studie där boende i Linköping deltog. Syftet med studien var att undersöka om avståndet mellan området där man bor och platsen för sprängningen har betydelse för graden av emotions och beteendeförändring efter händelsen. Ett förväntat resultat var att de som bor geografiskt nära sprängningen skulle få en högre grad av förändringar än boende längre bort och det visade sig stämma. Hypoteserna får stöd av resultatet som visar tydligt att efter sprängningen ökar benägenheten hos de som bor närmast (2 km från händelsen) att ta avstånd till okända människor. Människor i området närmast har svarat att de ändrat rörelsemönster i hur de tar sig fram och vistas i staden samt att de fått större känsloförändringar. De som bor närmast händelsen har fått störst beteendeförändringar totalt.

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    Bielsten, Therése
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Nursing Sciences and Reproductive Health. Linköping University, Faculty of Medicine and Health Sciences.
    “Doing things together”: Towards a health promoting approach to couples’ relationships and everyday life in dementia2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: Most people with dementia live in their own homes, often together with their partners, who become informal caregivers. Relationship quality and sense of couplehood can be threatened as a result of the transition from a mutually interdependent relationship to a caregiver-care-receiver relationship. This, in turn, may lead to many negative consequences for both partners. Support provided for couples is often divided into different types for the person with dementia and for the partner without dementia and lacks couple-based support that targets the relationship, resources and the couple’s everyday life together.

    Aim: The overall aim of this thesis is to explore couple-centred interventions in dementia and to develop and test a salutogenic, resource-oriented and couple-based intervention among couples in which one partner has dementia living at home.

    Methods and findings: This thesis comprises three parts: The first part Exploring involves two linked reviews, one narrative review (study I A) and one scoping review (study I B) that aim to identify and describe what previous couple-centred interventions comprised and why they were conducted. The results of the reviews revealed a knowledge gap in and a need for easily accessible support that targets couple relationships, resources and everyday life. The second part Developing (study II) refers to the development of an easily accessible resource-oriented couple-management intervention. The first step was to identify priority topics for such an intervention through a co-researcher process with couples living with dementia. This included a comprehensive literature review, interviews with couples in which one partner has dementia, and consultation meetings with expert groups of people with dementia and partners in both Sweden and the UK. The co-researcher process and the expert meetings informed four main themes with corresponding sub-themes that couples with dementia considered as important to their wellbeing in their everyday lives: (1) Home and Neighbourhood, (2) Meaningful Activities and Relationships, (3) Approach and Empowerment, and (4) Couplehood. The themes were further developed and integrated into the multimedia application DemPower, which was developed for the delivery of the intervention. The third part Testing and Evaluating describes a feasibility study (study III) in which the DemPower application was tested for feasibility and acceptability among couples in Sweden and the UK. The results of the feasibility study indicated that the DemPower intervention was feasible and acceptable among couples in which one partner has dementia living at home. The testing and evaluating part also comprise a qualitative study (study IV) that explores the experiences of engaging with DemPower together as a couple living with dementia in Sweden. The findings resulted in the three themes: (1) Growth of the relationship, (2) We are not alone, and (3) Positive approach, which the couples appreciated and associated with the resource-oriented and salutogenic approach of DemPower. The overall findings of the thesis are presented in a concluding synthesis at the end of the thesis. The concluding synthesis, focused on “Meaningfulness”, “Empowering health promotion”, “Normalization” and “Transitions and couplehood”, represents the core findings of this thesis.

    What this thesis adds: This thesis contributes to research, healthcare and the public by highlighting the need for a salutogenic approach toward couples living with dementia. The DemPower application, with its focus on couples’ relationships, resource-orientation and everyday life, has proven feasibility and acceptability and has meaningfully addressed a gap in the literature and in practice. As researchers, healthcare professionals and the public, we need to support couples where one partner has dementia to continue to live as normal life as possible. This can best be achieved by focusing on what couples can do, by inclusion and by valuing them as the experts within dementia research and of their life experiences.

    List of papers
    1. A review of couple-centred interventions in dementia: Exploring the what and why - Part A
    Open this publication in new window or tab >>A review of couple-centred interventions in dementia: Exploring the what and why - Part A
    2019 (English)In: Dementia, ISSN 1471-3012, E-ISSN 1741-2684, Vol. 18, no 7-8, p. 2436-2449Article, review/survey (Refereed) Published
    Abstract [en]

    Introduction Symptoms of dementia bring about challenges to couples relationships. Relationship-focused support has been highlighted to be of significant importance for sustained relationship quality and to reduce the negative impact of dementia on the dyadic relationship. This review aimed to explore the what and why of interventions aimed at couples where one partner has a diagnosis of dementia and in which the couple jointly participate. Method Searches were performed in Academic Search Premier, CINAHL, PsycINFO, PubMed, Scopus and Web of Science from January 2000 to August 2017. Results Six studies were included. Objectives for the person with dementia was related to cognitive function and for the care partner the objectives were related to well-being. The majority of the outcomes were mirrored by the objectives and focused on cognitive function for people with dementia and depression and relationship quality for care partners. Our findings indicate that people with dementia should be included in the assessment of the relationship in order to gain an overall picture of relationship dynamics and to increase tailored support in couple-centred interventions. Conclusions The findings of this review indicate that joint interventions for people with dementia and care partners are lacking a genuine dyadic approach where both partners views of their relationship are valued. In order to identify targets for support and to use the appropriate outcome measures, the quality of the relationship should be recognised and taken into account. Moreover, there is a lack of a salutogenic approach in couple-centred interventions in which couples strengths and resources can be identified and supported.

    Place, publisher, year, edition, pages
    SAGE PUBLICATIONS LTD, 2019
    Keywords
    caregiver; dementia; mild cognitive impairment; review; spouses
    National Category
    Gerontology, specialising in Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-160998 (URN)10.1177/1471301217737652 (DOI)000485953300002 ()29096533 (PubMedID)
    Available from: 2019-10-31 Created: 2019-10-31 Last updated: 2020-03-13
    2. Living Life and Doing Things Together: Collaborative Research With Couples Where One Partner Has a Diagnosis of Dementia
    Open this publication in new window or tab >>Living Life and Doing Things Together: Collaborative Research With Couples Where One Partner Has a Diagnosis of Dementia
    Show others...
    2018 (English)In: Qualitative Health Research, ISSN 1049-7323, E-ISSN 1552-7557, Vol. 28, no 11, p. 1719-1734Article in journal (Refereed) Published
    Abstract [en]

    The aim of this study is to identify relevant content for a self-management guide by using the outcomes of previous research in combination with knowledge and experiences from couples where one partner has a diagnosis of dementia. The study was carried out in three phases: (a) literature search of previous research related to well-being and couplehood in dementia; (b) interviews with couples with dementia based on the findings of the literature search; and (c) further authentication of the findings within expert groups of people with dementia and carers. For analysis of data, we used a hybrid approach of thematic analysis with combined deductive and inductive approaches. The findings of this study indicated that the four main themes Home and Neighborhood, Meaningful Activities and Relationships, Approach and Empowerment, and Couplehood with related subthemes could be appropriate targets for a self-management guide for couples where one partner has a diagnosis of dementia.

    Place, publisher, year, edition, pages
    SAGE PUBLICATIONS INC, 2018
    Keywords
    couples; collaborative research; dementia; salutogenesis; self-management; Sweden; thematic analysis; UK
    National Category
    Other Social Sciences not elsewhere specified
    Identifiers
    urn:nbn:se:liu:diva-151196 (URN)10.1177/1049732318786944 (DOI)000442412400004 ()30033851 (PubMedID)
    Available from: 2018-09-17 Created: 2018-09-17 Last updated: 2020-03-13