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  • Materez, Julia
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science.
    Rosqvist Nunes, Rebecca
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science.
    En oönskad resa: En litteraturstudie om upplevelser av att vara närstående till en ung vuxen i palliativ vård2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bakgrund: Palliativ vård utgör en viktig del av svensk sjukvård och bygger på fyra hörnstenar där närståendestöd är centralt. Detta medför att krav ställs på sjuksköterskor beträffande det stöd som de förväntas kunna ge en bred grupp individer med skilda egenskaper och behov. Närstående till unga vuxna i palliativ vård utsätts för en stor påfrestning då situationen avviker från förväntade livscykeln. Syfte: Beskrivaupplevelser av att vara närstående till en ung vuxen (16–30 år) i palliativ vård.

    Metod: En litteraturstudie med systematiskt tillvägagångssätt genomfördes, och tio vetenskapliga artiklar inkluderades i resultatet. Samtliga studier hade kvalitativ design.

    Resultat: Fyra huvudteman identifierades: Vikten av förtroendefulla relationer, Betydelsen av kommunikation, Behov av strategier för att orka med; Den terapeutiska miljöns inverkan på helheten. Ur dessa framkom åtta underteman: Relation till sjukvårdspersonal för kontinuitet; Relation till omgivning för stöd; Relation till den unga vuxna för att ta tillvara på tiden; Kontinuerligt och tydligt utbyte av information; Stöd vid svåra samtal; Coping för situationshantering; Hopp för situationshantering; Sjukhusmiljö och hemmiljö.

    Konklusion: Att vara närstående till en ung vuxen i palliativ vård innebar att genomgå en oönskad resa. För att som närstående hantera situationen var det viktigt att bli sedd och kontinuerligt informerad. För att kunna släppa kontrollbehovet behövde en känsla av förtroende för sjukvårdspersonal finnas och en terapeutisk miljö upplevas. Det är viktigt för sjuksköterskan att vara medveten om inverkande faktorer på närståendes helhetsupplevelse för att ge stöd och god vård vid livets slutskede.

  • Nasser, Mohamed
    Linköping University, Department of Computer and Information Science.
    The Study of the Relationship between Linguistic Skills and Psychological Disorders2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Our current knowledge about the relationship between linguistic skills and psychological disorders is somewhat diffuse. One reason is because it is difficult to investigate this relationship without including conditions that clearly influence the results in one way or another (e.g. culture, environment, socioeconomic class etc). This study aims to investigate the relationship in an attempt to highlight a potential link. By using the lens of several fields altogether; cognitive science, linguistics, neuroscience, neurocognition, this study shed light on the relationship and encourage further studies in this field to determine the role of linguistic skills in mental health in general. In the experiment, linguistic skills were measured opposed to depression as a specific disorder to quantify specific data. Linguistic skills were measured by density and diversity and PHQ-9 survey question were used to determine depression scale. Statistical analysis showed significant correlations between some measures of linguistic skills and PHQ-9. The significant statistical correlation found points towards the hypothesis that, better linguistic skills promote well-being, and psychological disorders take minor effect relative to poorer linguistic skills. This topic is large-scaled which means that background variables must be acknowledged thoroughly, which due to the extent of this thesis, were not. The results are discussed further as well as limitations of the study. Improvements for further research are proposed.

  • Ekstrand, Jonathan
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Education and Sociology.
    Hallberg, Oscar
    Linköping University, Department of Behavioural Sciences and Learning, Education and Sociology.
    Rekryterares uppfattning av anonymisering: Tankar kring ett första urval2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Uppsatsen syftar till att studera verksamma HR(Human resources)-praktiker inom rekryteringsområdets uppfattning gentemot användningen av ett anonymiserat första urval i rekryteringsprocessen. För att studera detta formuleras frågeställningar kring hur ett anonymiserat urval uppfattas av dessa praktiker samt vilka negativa och positiva aspekter de kan identifiera med ett sådant arbetssätt. Studien ämnar att undersöka detta via en kvalitativ studie med en induktiv ansats. Datainsamlingen sker via semistrukturerade intervjuer där praktikernas uppfattningar kring ämnet skiljer sig markant. Anonymisering ses som ett gynnsamt verktyg för kandidater där de får en mer rättvis chans att avancera i rekryteringsprocesser på bekostnad av rekryteraren som får en större arbetsbelastning. Studien mynnar ut i att rekryteringsförfarandet präglas av en situationsbetingad paradigm där olika organisationer är i behov av olika åtgärder. Således kan ett anonymiserat urval anses behövligt i organisationer där diskriminering förekommer medan organisationer med redan standardiserade och beprövade processer kan anse det som överflödigt.

  • Kronbäck, Susanna
    et al.
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Hendsel, Jevgenia
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Algebra på gymnasiet = Svårt?!: Förekomst av felsvar och feltyper vid åk 1-gymnasieelevers beräkningar inom algebra2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Innehållet i studien handlar om att kategorisera olika typer av fel som elever i åk 1 på gymnasiet gör i algebra. Data utgörs av 80 elevprov skrivna av elever på samhällsvetenskapsprogrammet och VVS- och fastighetsprogrammet läsåret 2017/2018 och 2018/2019. Uppgifterna som eleverna har fått göra är lösa ekvationer, förenkla uttryck, räkna värdet av ett uttryck samt problemlösning. Elevernas svar har analyserats och kategoriserats i sex feltyper: 1. Förståelsefel, 2. Procedurfel, 3. Modelleringsfel eller problemlösningsfel, 4. Resonemangsfel, 5. Redovisningsfel eller kommunikationsfel, 6. Övriga fel.

    I resultatet preseneteras varje feltyp illustrerad med elevexempel. Med tidigre forskning som utgångspunkt identifieras och diskuteras vilka missuppfattningar och svårigheter som kan vara den bakomliggande orsaken till att eleverna gjort dessa fel. 

    Några exempel på orsaker är att eleverna inte uppfattar variabelns (x) symboliska värde, förstår inte variablers generella beteckning (a och b), att variabeln kan representera en siffra, eleverna övergeneraliserar, förstår inte räkning med negativa tal, kan inte hantera aritmetik, förstår inte likhetstecknets betydelse, har oeffektiv resonemang (gissar, testar sig fram), samt skriver av uppgiften fel.

  • Carlsson, Anna
    et al.
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Marie, Liljeblad
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Speciallärares uppfattningar av bemötande av elever med låg motivation och låg självkänsla i matematiken: - En kvalitativ forskningstudie2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna studie är att beskriva och analysera speciallärares uppfattningar av hur de bemöter elever i årskurs 4till 6som har låg motivation och låg självkänsla inför matematiken. Studien är kvalitativ och utgår från en fenomenografisk ansats med syfte att öka kunskapen om speciallärares bemötande i matematiken. Metoden vi använde var kvalitativa intervjuer. Vi har gjort åtta stycken semistrukturerade intervjuer.

    Resultatet i studien visade att lärarnas bemötande medelever i matematiken påbörjas med relationen mellan lärare och elever. När eleverna upplever att relationen med lärarna är positiv har eleverna lättare för att få motivation till att lära. Resultatet visar också att lärare varierar sin undervisning och anpassar undervisningen efter elevernas förutsättningar. Det framkom också att lärare i sin undervisning utgår från elevernas arbetstempo och att möta eleverna på deras nivå för att öka elevernas självkänsla. Relationen mellan lärare och elever är även viktig i undervisningen. Känner eleven sig trygg med läraren är det lättare att motiveras till att lära och på så sätt kan elevernas självkänsla öka.

    I vår slutsats kom vi fram till att det är sociala aspekter som till exempel relationer mellan lärare och elev samt tryggheten i skolmiljön som påverkar elevers motivation och självkänsla. Andra faktorer som påverkar är elevers erfarenhet av motgång och framgång i sitt lärande samt deras positiva upplevelser inför matematiken. Både elevers självkänsla och motivation har ett samband med varandra.

  • Eriksson, Julia
    et al.
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Carlberg, Pernilla
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    "En kamp! Stackars barn som inte har föräldrar med kraft och resurser.": En studie av föräldrars perspektiv på språkstörning, skola och livskvalitet2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim of this study was to investigate the parents´ perspective of school, their experience of having a child with developmental language disorder (DLD) and their quality of life. A qualitative interview guide was used in three interviews with parents and a survey was answered by 76 parents. The material was analysed using thematic analysis and sorted into three main themes; effects on quality of life, experience we can learn from, and support for children in school. Teachers' relational skills and knowledge of DLD are of great importance. The results show that pupils with DLD are at risk of feeling depressed and that many parents are forced to fight for their children’s rights, to receive feedback, and have functional communications with teachers and other members of the school staff. In conclusion; everyone in school needs to meet parents with openness and accessibility, show understanding and work to eliminate obstacles in school. Furthermore, it is necessary to improve teachers´ knowledge about developmental language disorder.

  • Konpan, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Nanoscale engineering.
    Manipulation of thin metal film growth on weakly-interacting substrates using gaseous surfactants2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Thin films are structures with thicknesses ranging from the atomic scale to the mesoscale that are used to alter the properties of a surface and/or serve as functional layers in devices. Thin metal films deposited from the vapor phase on weakly-interacting substrates, including oxides (TiO2, ZnO, SiO2 etc.) and two-dimensional (2D) materials (graphene, MoS2, etc), are relevant for a wide array of technological applications, such as optical devices, nanoelectronic components, sensors, and catalytic devices. The weak interaction between deposit and surface in these film/substrate combinations leads to three-dimensional (3D) metal-layer morphological evolution in an uncontrolled manner; which often constitutes an important challenge toward integrating metal layers in key enabling devices. Thus there is a need for efficient growth manipulation strategies, such that metal films with controlled 3D and 2D microstructures and morphologies can be synthesized.

    Surfactants, i.e., minority metal, non-metal, and gaseous species which are deployed to the growing surface together with film-forming species, have been shown to enable growth manipulation in a multitude of homo- and heteroepitaxial metal/metal and semiconductor/semiconductor systems. This work explores the viability of N2 and O2 surfactants to manipulate growth in model weakly-interacting Ag/SiO2 and Au/SiO2 systems.

    Au and Ag are deposited by direct current (DC) magnetron sputtering on Si substrates covered with a 500 nm thick thermally grown SiO2 layer. Gaseous N2 and O2 surfactants are introduced to the sputtering atmosphere either continuously during deposition or at well-defined points during growth, such that specific film-formation stages as targeted. Using a combination of in situ/real-time diagnostic tools and ex situ characterization techniques, it is shown that O2 and N2 cause Ag and Au, respectively, to grow flatter, i.e., 2D growth morphology is promoted. Moreover, by deploying surfactants selectively during early or late film growth stages and studying their effect on film morphological evolution, it is concluded that N2 and O2 effectively suppress the rate of island coalescence promoting formation of flatter films.

    The overall results of this study are the first step toward establishing an atomic-scale understanding of the effect of surfactants on morphological evolution of metal films on weakly-interacting substrates. The knowledge generated herein is relevant for designing growth manipulation strategies in a wide range of technologically important film/substrate systems.

  • Dorri, Samira
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköpings universitet.
    Growth and Characterization of CrB2/TiB2 Superlattices by Magnetron Sputtering2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the present work, growth and structural characterization of CrB2/TiB2superlattices on (0001) Al2O3substrateis studied. The superlattices are grown using a direct current magnetron sputtering (DCMS) system with a base pressure of <9E-7 Torr.

    For structural characterization X-ray diffraction (XRD), X-ray reflectivity (XRR), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive X-ray spectroscopy (EDX), and scanning transmission electron microscopy (STEM) are used. Hardness is measured using nanoindentation technique.

    For growth of CrB2/TiB2superlatticesit is shown that the sputtering gas pressure of PAr= 4 mTorr, and substrate temperature of T= 600 °Care optimized parameters for growing well-structured superlattices with good interface quality. Superlattices with a layer thickness ratio of Γ= 0.43 (Γ= DTiB2/DCrB2+DTiB2) and a total thickness of 1 μm are deposited with different modulation periods Λ=1, 2, 6, 8, and 10 nm to see the layer-thickness affect on the quality of the structures. XRD and TEM results show that by increasing the modulation period, the quality of superlattices with smooth interfaces increases. The superlattices with modulation period Λ=8 nm is shown to be the best structure having coherent lattice and smooth interfaces up to ~20 periods. The STEM analysis shows that after about 20 periods, grains started to grow at slightly different orientations. A superlattice of TiB2/CrB2(having TiB2as the first deposited layer) with modulation period Λ=8 nm shows an epitaxial growth of TiB2on Al2O3(0001) substrate, however, no big difference between the structure of TiB2/CrB2and CrB2/TiB2superlattices is seen.

    EDX maps and line profiles show that there is a diffusion of CrB2into TiB2layerswhich is a serious problem for obtaining sharp interfaces. STEM also shows that for a small modulation period of Λ=1 nm, there is a faint layered structure, whereas EDX, SAED and XRD indicates a homogenous textures Ti-Cr-B film in this sample.

    Finally, the hardness measurement shows a hardness value of 29-34 GPa for different modulation periods. The lowest hardness value is related to the sample with modulation period ofΛ=1 nm with about 29 GPa, and the highest hardness is related to the sample with Λ=8 nm ith around 34 GPa.

  • Appelgren, Jennie
    et al.
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Axelsson, Ulrika
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Specialpedagogisk handledning i grundskolan: Lärares upplevelser av grupphandledning och dess effekter2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med uppsatsen var att utforska och få ökad förståelse för hur lärare som grupphandleds av en specialpedagog upplever handledning. Vi ämnade även utforska hur lärare upplevde grupphandledningens effekter i deras yrkesutövning. 

    Datainsamlingsmetoden som användesför studien var semistrukturerade intervjuer med tio utbildade grundskollärare. Analys av insamlade data genomfördes med hjälp av interpretativ fenomenologisk analys (IPA). Analysen genomfördes i två steg, där vi var för sig analyserade vårt material, för att sedan analysera och sammanställa alla data gemensamt.

    Studiens resultat visar att handledarens roll är avgörande för hur lärare upplever handledningen. Lärare upplever både för- och nackdelar med att handledas av en intern respektive en extern handledare. Handledarens kompetens påverkar både upplevelsen av handledningssituationen och handledningens effekter. Resultaten visar att lärare upplever tid och kontinuitet som viktiga aspekter. Att prioritera handledning upplevs viktigt, men om handledningen inte känns effektiv och givande, upplever lärare frustration över förlorad tid.

    Handledning upplevs av lärare vara viktig för den professionella utvecklingen. De områden som behandlas i handledningssituationen är främst personlig och kollegial utveckling. Lärare strävar efter en gemensam plattform och samsyn inom kollegiet, detta menar de ökar känslan av mod och styrka i personalgruppen.

    Resultaten visar att handledningens effekter inte alltid är de samma som lärare förväntar sig. De förväntar sig exempelvis större effekter gällande det gemensamma språket och en gemensam struktur. Handledning sätts ofta in för sent, lärare önskar att handledningen skulle vara med förebyggande än åtgärdande.

  • Nygren, Camilla
    et al.
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Hildingsson, Pia
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    "Så det är bara att ta skiten och typ kriga": Ungdomars upplevelser av att ha dyslexi i skolan2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This paper describes a qualitative study of upper-secondary students’ experiences of having dyslexia in the school environment. The purpose was to examine which positive and negative experiences they have had in school and how they experienced the support given. We also wanted to find out how they have felt about being diagnosed with dyslexia and whether/in what way the formal diagnosis changed their situation.

    We conducted semi structured interviews with seven upper-secondary students with dyslexia, and through interpretative phenomenological analysis came up with three themes. The results show that through time and experience the students learn to understand themselves and their difficulties better, but that they need support in this process. The study also points to the importance of students with dyslexia getting support by teachers who have knowledge of the disability and can offer the right kind of support, but who also see the students as individuals. Lastly, we found that in the students’ experience the best learning situation was offered to them in a smaller context outside the regular classroom setting.

    We draw three conclusions from our analysis: firstly, that it is important that teachers have a deep knowledge of dyslexia so as to individualize instruction. Secondly, that students need useful information about their disability on more than one occasion, and lastly, that mainstreaming isn’t always the best alternative for the student.

    We would welcome more research om how students receive information about their dyslexia and more studies on how to best organize special needs education, especially from a student perspective.

  • Lundberg, Åsa
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Ja, tänk att få ge den där stiftpennan till en elev som inte skriver: Några lärares upplevelse av inkludering och tillgänglig pedagogisk miljö2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med studien är att beskriva F-3 lärares uppfattningar om inkludering och tillgänglig pedagogisk miljö. Studien syftar även till att beskriva lärares erfarenheter av framgångsfaktorer och hinder i att skapa en inkluderande och tillgänglig pedagogisk miljö. Den metod som används i studien är induktiv tematisk metod. Sex F-3 lärare har intervjuats, intervjuerna kan beskrivas som kvalitativa och halvstrukturerade.  I denna studie framkommer det att lärare har olika uppfattningar av inkludering och tillgänglig pedagogisk miljö. Lärare beskriver att en framgångsfaktor är olika typer av anpassningar och strategier på individnivå och gruppnivå. Framgångsfaktorerna gynnar inkludering och när det fungerar väl för eleven tyder det på att inkluderingen fungerade. Trots detta framkommer det att lärare upplever svårigheter, vilket kan ses som dilemman, med att skapa en tillgänglig pedagogisk miljö.  Slutsatsen i min studie är att lärare står inför utmaningar i att skapa en tillgänglig pedagogisk miljö. Trots framgångsfaktorer som de nämner så har de inte rätt förutsättningar för att skapa en inkluderande och tillgänglig pedagogisk miljö. Brist på resurser och tid ses bland annat av lärare som ett hinder. När lärare behöver hjälp av specialpedagog/speciallärare får de inte alltid det. Lärares kunskaper i att bemöta elevers olikheter kan tolkas som bristfällig.

  • Aldén, Susanne
    et al.
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Aretorn, Åsa
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Tidig intervention i grundläggande taluppfattning: En insats på RTI-nivå 2 för elever i åk 1 som visat låga resultat2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Elever som har svårt att utveckla grundläggande taluppfattning ligger i riskzon för att hamna i matematiksvårigheter. Att istället tidigt få möjlighet att utveckla en god taluppfattning ger möjlighet att kunna följa den ordinarie matematikundervisningen i skolan med självförtroende och motivation.

    Syftet med detta arbete var att utvärdera effekten av en gruppintervention för elever som visat svagheter i sin taluppfattning. Den riktades mot åk 1 och arbetades fram utifrån explicit undervisning och den så kallade CRA-modellen med start i det konkreta för att via representationer mynna ut i mer abstrakta former. Insatsen genomfördes under 10-15 tillfällen, i enlighet  med RTI-modellens steg 2, i mindre grupper på 3 elever, och riktade in sig på konceptuell och deklarativ kunskap. Området som tränades var taluppfattning 0-100 och talkombinationer för talen 2-10 i addition och subtraktion.

    Studien genomfördes som en kvasi-experimentell studie. För- och eftertesternas resultat analyserades med ANOVA och en statistiskt signifikant effekt kunde utläsas till fördel för interventionsgruppen på den del av interventionen som berörde taluppfattning. Resultaten indikerar att tiden och metoden gjorde det möjligt för eleverna att förbättra konceptuell kunskap, men inte deklarativ kunskap.

  • Lisa, Eek
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Att skapa delaktighet i frågor som berör: En studie om specialpedagogers och speciallärares uppfattningar om elevers möjligheter till delaktighet i utformandet av särskilt stöd2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Alla elever skall ges samma möjlighet till delaktighet i sin lärmiljö i skolan och i frågor som rör dem. Samtidigt visar tidigare forskningsstudier på vilka utmaningar och svårigheter skolan ställs inför i arbetet med att skapa delaktighet för alla elever. Då forskning även visat att elever i behov av särskilt stöd eller med funktionsnedsättning upplever lägre grad av delaktighet blir det specialpedagogiskt relevant att fördjupa kunskaper kring detta.

    Syftet med denna studie var dels att undersöka specialpedagogers/speciallärares uppfattningar om delaktighetens betydelse för elevers lärande och utveckling med ett särskilt beaktande utifrån elever i behov av särskilt stöd. Vidare var syftet att söka förståelse för på vilka olika sätt de erfarit och uppfattar elevers möjlighet till delaktighet i utformandet av det särskilda stödet.

    Studien har en kvalitativ metodansats där nio semistrukturerade intervjuer med specialpedagoger och speciallärare har använts som metod för datainsamling. Den teoretiska utgångspunkt är Capability Approach från vilken begreppen resurs, funktion och handlingsutrymme har hämtats. Perspektivet har använts i analysen kring vad informanterna anser påverkar elevens handlingsutrymme.

    Resultatet understryker delaktighet som betydelsefull för elevens lärande och  utveckling, både i det långa perspektivet och i den pågående lärsituationen. Elevens möjlighet till delaktighet belyses i resultatet utifrån fem teman som lyfter relation, samtalet, samverkan, tydliggörande av den demokratiska processen och yttre ramar som viktiga påverkande faktorer. Resultatet visar även på vikten av pedagogens medvetenhet om alla dessa faktorers sammanflätning och påverkan på varandra. I diskussionen och analysen tolkas och diskuteras hur dessa faktorer påverkar varandra till att hindra eller möjliggöra handlingsutrymme för eleven.

  • Ghasemi Zinatabadi, Fatemeh
    et al.
    Linköping University, Department of Mathematics, Computational Mathematics. Linköping University, Faculty of Science & Engineering.
    Nordström, Jan
    Linköping University, Department of Mathematics, Computational Mathematics. Linköping University, Faculty of Science & Engineering.
    An Energy Stable Coupling Procedure for the Compressible and Incompressible Navier-Stokes Equations2019Report (Other academic)
    Abstract [en]

    The coupling of the compressible and incompressible Navier-Stokes equations is considered. Our ambition is to take a first step towards a provably well posed and stable coupling procedure. We study a simplified setting with a stationary planar interface and small disturbances from a steady background ow with zero velocity normal to the interface.

    The simplified setting motivates the use of the linearized equations, and we derive interface conditions such that the continuous problem satisfy an energy estimate. The interface conditions can be imposed both strongly and weakly. It is shown that the weak and strong interface imposition produce similar continuous energy estimates.

    We discretize the problem in time and space by employing finite difference operators that satisfy a summation-by-parts rule. The interface and initial conditions are imposed weakly using a penalty formulation. It is shown that the results obtained for the weak interface conditions in the continuous case, lead directly to stability of the fully discrete problem.

  • Pham, Thi
    Linköping University, Department of Computer and Information Science.
    Visualization and Classification of Neurological Status with Tensor Decomposition and Machine Learning2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Recognition of physical and mental responses to stress is important for stress assessment and management as its negative effects in health can be prevented or reduced. Wearable technology, mainly using electroencephalogram (EEG), provides information such as tracking fitness activity, disease detection, and monitoring neurologicalstates of individuals. However, the recording of EEG signals from a wearable device is inconvenient, expensive, and uncomfortable during normal daily activities. This study introduces the application of tensor decomposition of non-EEG data for visualizing and classifying neurological statuses with application to human stress recognition. The multimodal dataset of non-EEG physiological signals publicly available from the PhysioNet database was used for testing the proposed method. To visualize the biosignals in a low dimensional feature space, the multi-way factorization technique known as the PARAFAC was applied for feature extraction. Results show visualizations that well separate the four groups of neurological statuses obtained from twenty healthy subjects. The extracted features were then used for pattern classification. Two statistical classifiers, which are the multinomial logit regression(MLR) and linear discriminant analysis (LDA), were implemented. The results show that the MLR and LDA can identify the four neurological statuses with accuracies of 95% and 98.8%, respectively. This study suggests the potential application of tensor decomposition for the analysis of physiological measurements collected from multiple sensors. Moreover, the proposed study contributes to the advancement of wearable technology for human stress monitoring. With tensor decomposition of complex multi-sensor or multi-channel data, simple classification techniques can be employed to achieve similar results obtained using sophisticated machine-learning techniques.

  • Ghasemi Zinatabadi, Fatemeh
    et al.
    Linköping University, Department of Mathematics, Computational Mathematics. Linköping University, Faculty of Science & Engineering.
    Nordström, Jan
    Linköping University, Department of Mathematics, Computational Mathematics. Linköping University, Faculty of Science & Engineering.
    The Relation Between Primal and Dual Boundary Conditions for Hyperbolic Systems of Equations2019Report (Other academic)
    Abstract [en]

    In this paper we study boundary conditions for linear hyperbolic systems of equations and the corresponding dual problems. In particular, we show that the primal and dual boundary conditions are related by a simple scaling relation. It is also shown that the weak dual problem can be derived directly from the weak primal problem.

    Based on the continuous analysis, we discretize and perform computations with a high-order finite difference scheme on summation- by-parts form with weak boundary conditions. It is shown that the results obtained in the continuous analysis lead directly to stability results for the primal and dual discrete problems. Numerical experiments corroborate the theoretical results.

  • Ghasemi Zinatabadi, Fatemeh
    et al.
    Linköping University, Department of Mathematics, Computational Mathematics. Linköping University, Faculty of Science & Engineering.
    Nordström, Jan
    Linköping University, Department of Mathematics, Computational Mathematics. Linköping University, Faculty of Science & Engineering.
    On conservation and dual consistency for summation-by-parts based approximations of parabolic problems2019Report (Other academic)
    Abstract [en]

    We consider the coupling of parabolic problems discretized using difference operators on summation-by-parts (SBP) form with interface conditions imposed weakly. In [1, 2], it was shown that conservation and dual consistency are equivalent concepts for linear conservation laws. Here, we show that these concepts are equivalent also for symmetric or symmetrizable parabolic problems, exemplified by the heat equation. We rewrite the heat equation as first order system as in the local discontinuous Galerkin method and show the equivalence of dual consistency and conservation for both the first and second order forms.

  • Schneider, Linda
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Educational Sciences.
    Skolethnos: Inkludering av nyanlända elever i en svensk skola2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    How does the inclusion of newly arrived students into the Swedish school system look today? There are discussions about multicultural schools and an increased proportion of students with different ethnicities in our schools, but how does this look from an inclusion perspective within the schools? There are a lot of laws, ordinances, norms, values ​​and cultures that the schools have to relate to when it comes to the inclusion of newly arrived pupils, however, these are interpretable and it is not always that practice corresponds to theory. It does not always mean that the pupils experience a complete and positive inclusion just because they are included in the school physically, this in turn affects the students learning ability and their views on the Swedish society. Research shows that the use of an intersectional perspective can help teachers, and other staff who work with newly arrived students, to gain an in-depth understanding of the student´s needs. Results show that the best way to support the newly arrived during their schooling is if the teacher takes the time to reach out to the student to create an in-depth understanding of the student´s needs and it also ensures that the inclusion is done properly at an individual level.

  • Franzén, Sandra
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Striem, Ida
    Linköping University, Department of Behavioural Sciences and Learning, Education, Teaching and Learning. Linköping University, Faculty of Educational Sciences.
    Etiskt rätt eller fel? Bedömningsdilemman i en skola för alla: En kvantitativ studie av ställningstaganden från speciallärar- och specialpedagogstudenter samt läraratudenter i Sverige, USA och Kina2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Etiska dilemman är något lärare möter dagligen och detta särskilt i arbetet med elever i svårighet (Pope, Green, Johnson & Mitchell, 2009). Speciallärare och specialpedagoger ska i dessa situationer kunna bidra med stöd och handledning till lärarna (Skolverket, 2018a). I denna studie undersöks och jämförs hur olika studentgrupper tar ställning till etiska dilemman rörande bedömningssituationer och då i synnerhet i förhållande till arbetssätt och anpassningar vilka kan gynna elever i svårighet.

    Utgångspunkten i studien är en kvantitativ metod där studenter tar ställning till  olika scenarier och huruvida de anses vara etiskt rätt eller fel. Denna studie bidrar med empiri  från studenter på speciallärarprogrammet och specialpedagogprogrammet. Även tidigare insamlad data från lärarstudenter inom sin grundutbildning presenteras och analyseras, vilket även görs med data från lärarstudenter från USA och Kina.

    Resultatet visar i likhet med tidigare studier (Liu, Johnson & Fan, 2016; Green, Johnson, Kim & Pope, 2007) att det finns behov av att förankra och stärka etiska riktlinjer inom lärarutbildningen. Vidare pekar vårt resultat på att blivande specialpedagoger och speciallärare har stark enighet kring vad som är etiskt i förhållande till bedömning inom ett flertal områden och att blivande lärare har behov av stöd då det kommer till  kunskapsbedömning och då i synnerhet i förhållande till elever i svårighet. Internationellt sett kan vi se både likheter och skillnader i de ställningstaganden studenterna gör, dock visar de svenska lärarstudenterna en större enighet utifrån riktlinjer kring klassrumsbedömning.

  • Syssner, Josefina
    et al.
    Linköping University, Department for Studies of Social Change and Culture, Centre for Municipality Studies – CKS. Linköping University, Faculty of Arts and Sciences.
    Olausson, Albin
    Linköping University, Department of Management and Engineering, Political Science. Linköping University, Faculty of Arts and Sciences.
    Att främja utveckling inom besöksnäringen2019In: Entreprenörskap för en levande landsbygd: 15 texter om landsbygdsutveckling och entreprenörskap i Norrland / [ed] Karl Wennberg, Familjen Kamprads stiftelse , 2019, p. 279-294Chapter in book (Other academic)
    Abstract [sv]

    Besöksnäringen lyfts fram som allt viktigare för utveckling och tillväxt på den svenska landsbygden. Besöksnäringen har ett antal särskilda karaktärsdrag som är viktiga att känna till om branschen ska kunna nå den potential den ofta tillskrivs.

    Besöksnäringen är platsspecifik och måste därför utvecklas i relation till platsens natur, kultur och sociala karaktärsdrag.

    En destination utgörs ofta av ett stort antal, små och stora, kommersiella och icke-kommersiella aktörer, vilket skapar utmaningar när det kommer till styrning av besöksnäringens utveckling.

    Besöksnäringens utveckling kantas av att olika intressen möts och ibland hamnar i konflikt med varandra. För att besöksnäringens utveckling ändå ska kunna styras krävs ett aktivt ledarskap och forum för strategisk styrning.

  • Bons, Daniel
    Linköping University, Department of Biomedical Engineering.
    Modelling peripheral vision in dynamic situations2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Metamers of the ventral stream is a model which tries to describe what information we gather from our visual field. It have previously only been tested on static images. This thesis have continued the research and applied it to dynamic images in order to investigate if the model can be seen as a functional representation of our visual field. The results show that the model, at this stage, can not be seen as a fully functional representation of the visual field, but it can be used to determine the detectability of objects in the periphery. It also shows that what we humans perceive as motion is, at least to some extent, merely a change of the statistics in our visual field. 

  • Skagius, Peter
    Linköping University, Department of Thematic Studies, Department of Child Studies. Linköping University, Faculty of Arts and Sciences.
    Brains and psyches: Child psychological and psychiatric expertise in a Swedish newspaper, 1980–20082019In: History of the Human Sciences, ISSN 0952-6951, E-ISSN 1461-720X, no 3, p. 76-99Article in journal (Refereed)
    Abstract [en]

    Most children and families have not had direct contact with child psychological and psychiatric experts. Instead they encounter developmental theories, etiological explanations and depictions of childhood disorders through indirect channels such as newspapers. Drawing on actor–network theory, this article explores two child psychological and psychiatric modes of ordering children’s mental health discernible in Sweden’s largest morning newspaper, Dagens Nyheter, during the years 1980 to 2008: a psychodynamic mode and a neuro-centered mode. In the article I show how these two relatively contemporaneous modes greatly differed in how they enacted children’s mental health. The psychodynamic mode stressed the parents’ role in structuring and affecting the child’s unconscious and saw them as the primary cause of any mental illness. In contrast, the neuro-centered mode highlighted that mental issues were related to the child’s brain and proposed different solutions depending on whether the child’s brain functioned in a ‘normal’ or ‘atypical’ manner. Each mode moreover suggested differing contexts to their discussions, with the psychodynamic mode solely discussing the parental milieu while the neuro-centered mode mainly focused on how society affected children with ‘atypical’ brains. The two modes thus had significantly diverging implications for the reader on how to understand and manage children and their psychological well-being. I further argue in the article for the relevance of actor–network theory in historical studies of psychology and psychiatry.

  • Stenborg, Vera
    et al.
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Högren, Louise
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    “People analytics kan jämföras med tonårssex: alla pratar om det, ingen har gjort det och ingen vet hur man ska göra”: En kvalitativ studie om hur svenska praktiker upplever people analytics2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Teknisk utveckling har varit en drivande kraft för effektivisering av organisationer genom historien. I takt med denna effektivisering har även arbetssätt och krav på anställda förändrats vilket har lett till ett behov av att strukturerat hantera personalrelaterade frågor. Utifrån detta har human resources (HR) som organisatorisk funktion vuxit fram. Den tekniska utvecklingen fortsätter och idag används tekniska lösningar som verktyg för många av organisationens funktioner. Dock menar tidigare forskning att HR inte hänger med i denna utveckling vilket påverkar HR-funktionens roll i organisationen och är en utmaning idag och framöver. En uppmärksammad teknisk lösning idag, i form av en uppsättning teknikbaserade vertyg, aktiviteter och arbetssätt, som anses kunna hjälpa HR som funktion att ta nästa steg i utvecklingen är people analytics.

    Syftet med denna studie är att öka förståelsen för people analytics i Sverige, vilka effekter som eftersträvas samt vilka möjligheter och utmaningar som finns för att uppnå dessa effekter. Detta grundar sig i att det finns ett behov av empiriskt grundad forskning i en svensk kontext eftersom det finns en avsaknad av detta idag. Genom tillämpning av en kvalitativ surveyundersökning av tolkande karaktär med semistrukturerade intervjuer framkommer ett empiriskt material som analyseras med hjälp av tidigare forskning och socioteknisk teori. Studien visar att people analytics är en uppsättning aktiviteter som är värdefulla för såväl organisationer som HR-funktioner eftersom det möjliggör evidensbaserat strategiskt arbete, med data och statistik som grund, i personalrelaterade frågor. Genom att använda people analytics kan organisationer följa upp sitt personalrelaterade arbete på ett mer strukturerat sätt och HR som funktion har även fått ökad legitimitet i organisationen på grund av detta. Däremot finns det ett antal komplext sammanflätade faktorer som idag agerar hindrande för att people analytics ska nå sin fulla potential i svenska organisationer, dessa faktorer återfinns både i sociala och tekniska aspekter av arbetet med people analytics. Genom att skapa förståelse för varför dessa faktorer påverkar användandet och effekterna av people analytics bidrar denna studie med värdefulla insikter för både praktiker och akademiker. Dessa insikter handlar om hur arbetet med people analytics kan uppnå de långsiktiga mål och syften som finns både inom forskning och hos svenska organisationer.

  • Mardini, Lama
    Linköping University, Department of Behavioural Sciences and Learning.
    Att arbeta med formativ bedömning: En intervjustudie med rektorer och lärare2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med min studie är att ta reda på hur lärare och rektorer i grundskolan beskriver att de arbetar med formativ bedömning för att stärka lärande. I forskningsläge presenterar jag teori och forskningar om formativbedömning och dess nyckelprocesser. I resultatet beskriver jag lärares och rektorers uppfattningar om begrepp och genomförande av formativ bedömning samt hinder som de upplever med arbetet. Resultatet visar att informanterna anser att tydlig information om målen kan underlätta lärande. Återkopplingen kan också utveckla elevs kunskaper. Genom självbedömning kan eleverna få djupare förståelse för sin nivå. Kamratbedömning ger eleverna möjligheter att få höra återkoppling på ett annat språk. Hela processen kräver att lärare och rektorer fungerar som vägledare. Avslutningsvis presenterar jag nya forskningsfrågor som kan komplettera min studie.

  • Rönnberg, Nico
    Linköping University, Department of Management and Engineering, Political Science.
    Sveriges Kommuner och Landsting (SKL) – en postkorporativ kvarleva eller en kvasistatlig hybrid?: En undersökning av SKL:s roll och inflytande i två politiska beslutsprocesser2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this thesis is to study the role and the influence of the Swedish local government association, SALAR, which is an interest group representing all of the Swedish local authorities and regions. As a result of a change in exercising public power from government to multi-level governance that has reinforced subnational level, including local authorities and regions, SALAR is today a significant actor. It has an intermediating role in the relation between the government and local and regional authorities. SALAR is a hybrid organization that has interest group and governmental characteristics. It is a player competing with other interest groups in a pluralistic system but it is also a corporatist negotiation partner of the government that has a privileged access to central government decision-making. This study uses a comparative case study method analyzing two policy processes to study and describe what kind of role and influence SALAR has in these processes and how the role and the influence of SALAR can be understood from an interest group perspective and a multi-level governance perspective. The described and analyzed policy processes are Kömiljarden, an effectivity effort in Swedish public health care system, and the introduction of the teacher license system in Swedish schools. The empirical material used in this thesis consists of official publications published by public authorities, the parliament and the government as well as interviews with officials representing public authorities, the government and SALAR. The results presented in this thesis show that SALAR in line with previous research on local government associations in other countries, has a role as an intermediator with a privileged access to central government and central decision-making. It is a partner that central government negotiates with and which has the task of informing about the local and regional circumstances. Its influence can also be analyzed in connection to these negotiations. SALAR is in many ways stuck in the structure of decision-making, which is operated by central government while still being in competition with interest groups, such as the teacher unions.

  • Melén, Daniel
    Linköping University, Department of Management and Engineering, Political Science.
    Mellanöstern - Dess Asabiyah och rentierism: En kvalitativ textanalys av det saudiska kungadömets sociala baser och distributionsmodeller2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Saudi Arabia, Rentier state, Asabiyah, Neopatrimonialism and Saudi Vision 2030.

  • Axelsson, Lisa
    et al.
    Linköping University, Department of Social and Welfare Studies.
    Cronstrand, Peter
    Linköping University, Department of Social and Welfare Studies.
    "Eftersom skolan ligger som den gör så blir det...": Lärares uppfattningar om hur skolors placering påverkar SO-undervisningen i F-32019Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta är en kvalitativ studie om hur lärare arbetar med skolans närområde i sin undervisning,samt vilken påverkan närområdet har på lärares förutsättningar för undervisning. Studien byggerpå 7 stycken semi-strukturerade intervjuer med lärare på landsbygd och i stadsmiljö. Studienvisar på att lärare på landsbygden använder utomhusmiljön i närområdet mer i sin undervisningän lärare i stadsmiljö. Lärarna i stadsmiljö har däremot större förutsättningar för att göra olikatyper av studiebesök. Utifrån den mer heterogena etniska sammansättningen i stadsmiljöpåverkas lärarnas undervisning i svenska och religion på olika sätt. Förutsättningarna kan alltsåskilja sig åt på olika sätt, men lärare är vana och skickliga på att anpassa sig efter deförutsättningar de har och nyttja dem på bästa sätt.

  • Gustafsson, Mariana S.
    et al.
    Linköping University, Department of Management and Engineering, Political Science. Linköping University, Faculty of Arts and Sciences.
    Elvström, Rebecca
    Motala kommun.
    Skill, Karin
    Linköping University, Department of Management and Engineering, Political Science. Linköping University, Faculty of Arts and Sciences.
    Wihlborg, Elin
    Linköping University, Department of Management and Engineering, Political Science. Linköping University, Faculty of Arts and Sciences.
    DigidelCenter i Motala: Lärdomar för ökad digital kompetens2019Report (Other academic)
    Abstract [sv]

    Digital delaktighet är en demokratisk rättighet. Därför är digitalt utanförskap ett demokratiskt problem när allt fler offentliga tjänster hanteras i digitala kanaler med allt från bankärenden till skolfrågor, bussturlistor och kommunal information. I FN:s Agenda 2030 för hållbar utveckling, som ligger till grund för en del av forskningen som presenteras i denna rapport, talas det om att ingen ska lämnas efter eller utanför – alla ska med. Vi tar denna uppmaning från global policy som ett riktmärke för studier av lokal praktik.

    I rapporten presenteras kommunens och bibliotekens roll i vår digitala omvärld. På biblioteket stöttar medarbetarna medborgarna med både informationsinhämtning och att lära sig att använda digital teknik. Biblioteksmedarbetarna arbetar också med yttrandefrihet, medie- och informationskunskap och hållbar utveckling. Vi beskriver arbetet på bibliotek för att kunna tillmötesgå såväl politiska förväntningar och lokala realiteter, som vilka kompetenser personalen behöver och hur arbetet kan organiseras. Ett syfte har även varit att sprida erfarenheter av de arbetssätt för digital delaktighet som utvecklas på DigidelCenter i Motala, till i första hand politiker och tjänstemän i Sverige. Karaktären på studierna har varit aktionsforskning där design och resultat kontinuerligt diskuteras med intresserade aktörer i kommunen och på bibliotek i samverkan, i Östergötland.

    I rapporten beskriver och analyserar vi arbetet på DigidelCenter i Motala kommun som en demokratisk arena. Motalas arbete har i flera sammanhang lyfts fram som en framgångsrik modell för att stödja digital inkludering, bland annat av digitaliseringsministern Peter Eriksson vid hans besök våren 2018. Det framhölls även när regeringen lanserade en satsning på flera DigidelCenter runt om i Sverige och sköt till medel för arbetet (Regeringen Pressmeddelande, 2018). Därför står arbetet på Motala bibliotek i fokus här.

    En utmaning här är svårigheterna att mäta digital kompetens, men även hur den kan studeras och beforskas. I policydokument finns många olika perspektiv som pendlar mellan uppfattningar om enskilda personers kompetens att vara aktiva medborgare (EU:s styrdokument/ EU, 2017?), till krav på tjänstemän och medarbetares digitala kompetens att kunna förklara för andra, visa och leda (OECD, 2017). I båda fallen handlar det om vad som händer i möten med digital teknik.

    Vi presenterar resultat från aktiviteter med besökare och deltagare i DigidelCenters verksamhet i form av observationer, en enkätstudie, och intervjuer med bibliotekspersonal och kommunala politiker. Dessa olika sammanhang visar på vad vi måste förstå för att tala om digital delaktighet i det offentliga, det vill säga det vi har för avsikt att studera inom forskargruppen DINO.

    Resultaten indikerar att arbetet med digital inkludering behöver fortsätta, samt att det handlar om mer än tillgång till teknik - kompetens är också viktigt. Resultaten från DigidelCenter i Motala visar även att personal som i sin tjänst möter människor med digitala frågor behöver både pedagogisk kompetens och kännedom om samhällets logik kring var olika e-tjänster ”hör hemma”. Dessa resultat kommer att bidra till att utveckla stöd för dem som arbetar med digital kompetens och inkludering.

  • De Biase, Alessia
    Linköping University, Department of Computer and Information Science, The Division of Statistics and Machine Learning.
    Generative Adversarial Networks to enhance decision support in digital pathology2019Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Histopathological evaluation and Gleason grading on Hematoxylin and Eosin(H&E) stained specimens is the clinical standard in grading prostate cancer. Recently, deep learning models have been trained to assist pathologists in detecting prostate cancer. However, these predictions could be improved further regarding variations in morphology, staining and differences across scanners. An approach to tackle such problems is to employ conditional GANs for style transfer. A total of 52 prostatectomies from 48 patients were scanned with two different scanners. Data was split into 40 images for training and 12 images for testing and all images were divided into overlapping 256x256 patches. A segmentation model was trained using images from scanner A, and the model was tested on images from both scanner A and B. Next, GANs were trained to perform style transfer from scanner A to scanner B. The training was performed using unpaired training images and different types of Unsupervised Image to Image Translation GANs (CycleGAN and UNIT). Beside the common CycleGAN architecture, a modified version was also tested, adding Kullback Leibler (KL) divergence in the loss function. Then, the segmentation model was tested on the augmented images from scanner B.The models were evaluated on 2,000 randomly selected patches of 256x256 pixels from 10 prostatectomies. The resulting predictions were evaluated both qualitatively and quantitatively. All proposed methods outperformed in AUC, in the best case the improvement was of 16%. However, only CycleGAN trained on a large dataset demonstrated to be capable to improve the segmentation tool performance, preserving tissue morphology and obtaining higher results in all the evaluation measurements. All the models were analyzed and, finally, the significance of the difference between the segmentation model performance on style transferred images and on untransferred images was assessed, using statistical tests.

  • Hakkestad, Mårten
    et al.
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Rynningsjö, Simon
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Who hacked my toaster?: A study about security management of the Internet of Things.2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Internet of Things is a growing area with growing security concerns, new threat emerge almost everyday. Keeping up to date, monitor the network and devices and responding to compromised devices and networks are a hard and complex matters. 

    This bachelor’s thesis aims to discover how a IT-company can work with security management within the Internet of Things, this is done by looking into how a IT-company can work with updating, monitoring and responding within the Internet of Things, as well what challenges there are with working with this. 

    A qualitative research approach was used for this case study along with an interpretative perspective, as well as abductive reasoning. Interviews were performed with employees of a large IT-company based in Sweden, along with extensive document analysis. 

    Our bachelor’s thesis results in challenges with Security Management within the areas updating, monitoring and responding along with how our Case Company works with these security challenges. Largely these challenges can be summarized that everything is harder with the number of devices there are within the Internet of Things

  • Johansson, Johannes
    et al.
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Alonso, Fabiola
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Modelling Details for Electric Field Simulations of Deep Brain Stimulation2019In: WORLD CONGRESS ON MEDICAL PHYSICS AND BIOMEDICAL ENGINEERING 2018, VOL 1, SPRINGER , 2019, Vol. 68, no 1, p. 645-648Conference paper (Refereed)
    Abstract [en]

    Deep brain stimulation is a well-established technique for symptomatic treatment of e.g. Parkinsons disease and essential tremor. Computer simulations using the finite element method (FEM) are widely used to estimate the affected area around the DBS electrodes. For the reliability of the simulations, it is important to match used simulation parameters with experimental data. One such parameter is the electric field magnitude threshold EFt required for axon stimulation. Another is the conductivity of the perielectrode space (PES) around the electrode. At the acute stage after surgery the PES will be characterized by an increased conductivity due to inflammation and edema while the later chronic stage will be characterized by a lower conductivity due to gliosis and minor scar formation. In this study, the EFt and the electric conductivity of the PES have been estimated by comparing FEM simulations with clinical studies of activation distance, pulse length and electrode impedance. The resulting estimates are an EFt of 0.2 V/mm at the common pulse width of 60 mu s and a chronaxie of 62 mu s. Estimated electric conductivities for the PES are 0.14 S/m in the acute stage and 0.05 S/m in the chronic stage, assuming a PES width of 250 mu m. These values are thus experimentally justified to use in FEM simulations of DBS.

  • Gunneström, Klara
    et al.
    Linköping University, Department of Management and Engineering, Malmstens Linköping University.
    Torell Nordgren, Elsa
    Linköping University, Department of Management and Engineering, Malmstens Linköping University.
    Vulst på ram nr. 1-7: En formsökande studie i tapetserarhantverket2019Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [sv]

    Vi utforskar vulsten, ett återkommande moment för möbeltapetserare, och från ett nytt och ej funktionsgivet sätt placerar vi den på ram för alla att se.

    När en tapetserare ska ta sig an momentet vulst så utgår hen från hur en, i möbelsammanhang, stomme är utformad och vilken sorts vulst som passar till just den möbeln. Ramarna för hur vulsten skall se ut är nästintill förbestämd då ett slutgiltigt resultat ofta ska återskapas eller restaureras i äldre objekt. I nya möbler finns ingen mall och på så sätt lite mer frihet hur vulsten kan utformas men funktionen är densamma. Vulsten ska hjälpa stoppningen att ge slutgiltig form, karaktär och känsla till möbelns slutgiltiga uttryck. Det som vulsten har gemensamt i båda fallen är att den alltid är dold.

    Genom ett formsökande i det traditionella tapetserarhantverket samt på ett inspirationsbaserat plan har vi tagit fram ett antal prover på olika varianter av vulst. Vulsten har fått möjlighet att förändras och formas med hjälp av olika stygntekniker. Med ett syfte att på ett visuellt och icke funktionsbaserat sätt synliggöra en tapetserares dolda hantverk vill vi påvisa ett annat sätt att förhålla sig till detta specifika moment och det givna hantverket.

  • Björklund, Lowe
    et al.
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Fogelström, Alma
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Effektivitet inom sjukvården: En kvalitativ fallstudie om avlastning för sjukhuspersonal inom en sektion vid ett sjukhus i Sverige2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this Bachelor Thesis was to describe if and in what way the connection with the RIA-project within the section at the hospital in Sweden has been effective in relation to the goal that has been established by the section.

    The theoretical framework proceeds from two models that deals with effectiveness which have been adapted to the human resource. The framework treats efficiency and effectiveness with associated subheadings, specifically: Resources, competency, job assignments and goal.

    The study was a qualitative case study with a descriptive nature and a deductive approach. Primary data was collected with accessibility selection with semi-structured interviews with seven respondents. The empirical findings were analysed with a thematic analysis method with themes related to the theoretical framework. The study collected secondary data from books, academic articles and academic journals.

    Empirical data was collected from hospital staff and hospital management within the section at the hospital in Sweden.

    The study reaches the conclusion that the connection with the RIA-project within the section at the hospital in Sweden has been effective in relation to the goal that has been established by the section, but not to what degree it has been effective. The human resources can do more right things, the hospital staff uses its competence to a higher degree and the hospital staff can perform job assignments right in relation to what is associated with their profession. This in turn have led to faster processing and contributed to efficiency which in turn have led to effectiveness in relation to the goal that has been established by the section.

  • Follin, Hector
    et al.
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Hallenberg, Daniel
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Utveckling av tjänstefiering genom värdekonstellationer: En studie om hur företag med knappa resurser kan tillhandahålla erbjudanden som främjar relationer och en cirkulär ekonomi2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Information technology, IT, and sustainability work have become strategic questions in almost any business. Not only do firms have to implement IT to optimize current operations, they must transform into new business models which requires high level of competence and strategic thinking which especially small and medium-sized enterprises, SME, tend to lack. Buying refurbished IT-hardware is an option for SME to act sustainable. However, suppliers of those goods seldom offer much more as they too tend to lack the resources needed to provide IT services. IT services are usually critical whether SME will become customers or not since buying IT from one supplier minimizes administration costs as well as it creates deeper relationships. Lack of internal resources has led to SMF outsource parts or whole operations more frequently to external suppliers. But the outsourcing does not come harmless. Leaving an operation to an external supplier requires close relationship with the supplier to maintain quality, making the communication vital. A way for a supplier to facilitate relationships is to develop servitization, i.e go from product- to service-centric offers. To develop servitization regardless the scarce resources suppliers have to co-produce offers. Creating an interactive strategy in networks consisting of actors that co-produce offers creates new value creating systems- value constellations. Suppliers and customers are now part of the value creation as they both participate in the production. Their roles have been broadened and the scarce resources as a barrier has now been eliminated as they now share competences while their relationships are being flourished.

  • Gränström, Danielle
    et al.
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Atterström, Johanna
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    E-handel av livsmedel: En kvalitativ studie som undersöker hur e-service quality påverkar kundens köpbeteende2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Introduction: E-commerce has shown a large increase in the last years and constitutes a great portion of the market. This has led to a digital shift and more people choose to e-shop. This has affected the retail business, since there are new, more comfortable ways to buy your groceries. Furthermore, the food e-commerce differentiates from the general e-commence, since customers feel comfortable being able to smell, touch and see the groceries they are buying.

    Purpose: The purpose of this study is to achieve a higher and deeper knowledge of how the e-service quality affects the customers purchasing behavior in a digital food commence. Furthermore, the purpose is to identify notable factors within e-service quality which affects the customers purchasing behavior.

    Method: This is a qualitative study which has had an abductive approach. It is a combination between an inductive and a deductive attempt. The empirical material has been collected through six semi-structured interviews with Zeithaml, Parasuraman & Malhotra (2002) e-service quality dimensions for basis. Thereafter the empirical results were analyzed with the different steps of the buying process.

    Conclusion: Through this study, we noticed no significant difference between the interviewees which probably is a result of a high "internet habit". Thanks to the study, we were able to conclude that there are a number of distinct factors within the e-service quality dimensions that affects the customers purchasing behavior. Seeing that this is a subject going through constant development in contemporary with the digital evolution we find it useful to study, because the old barriers are replaced with new ones.

  • de Luca, Vanessa
    et al.
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Rhan, Jacob
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Sökmotoranvändares annonsmedvetenhet och attityd mot organiskaoch betalda sökresultat: En kvantitativ studie om hur sökmotoranvändares attityd påverkas av annonsmedvetenhet2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Purpose: The purpose of this study is to examine if there is a relationship between search engine users advertising awareness and attitude towards organic- and/or paid search results.

    Hypothesis: H1: The attitude toward Google´s paid search results is significantly more negative for search engine users who successfully identify more than 75% of Google´s paid search results on the results page compared to search engine users who successfully identified less than 75% of Google´s paid search results on the search results page. H2: The attitude toward Google´s organic search results is significantly more negative for search engine users who successfully identify more than 75% of Google´s paid search results on the search results page compared to search engine users who successfully identified less than 75% of Google´s paid search results on the search results page.

    Methodology: The study is based on the positivist research paradigm and has a quantitative research method and a deductive approach. The research design is a cross- sectional study and a survey has been chosen as a data collection method. The data analysis was completed using the computer program IBM SPSS.

    Results: The results show that there is no relationship between the search engine user´s attitude towards Google´s paid search results and the search engine user´s ad awareness, which means that the null hypothesis 1 cannot be rejected. The results also show that search engine user´s attitude towards Google´s organic search results is significantly more positive for search engine users who identified more than 75% of Google´s paid search results on the search results page as compared to search engine user´s successfully identified less than 75% of Google´s paid search results on the search results page, meaning, the null hypothesis 2 cannot be rejected.

    Contributions: The theoretical contribution is related to persuasion knowledge model (PKM) and shows that (1) search engine user´s activation of persuasion knowledge does not necessarily create a more negative attitude towards paid search results. (2) Search engine user´s activation of persuasion knowledge creates a more positive attitude towards organic search results. The practical contribution is given to Google and is based on the fact that (1) Google can clarify its ad disclosure without the risk of search engine users creating more negative attitude towards paid search results. (2) Google can clarify the ad disclosure, which will lead to more positive attitude towards organic search results for search engine users.

  • Mahmoud Nejad, Sama
    et al.
    Linköping University, Department of Social and Welfare Studies, Learning, Aesthetics, Natural science.
    Ahlberg, Robin
    Linköping University, Department of Social and Welfare Studies.
    Lugna aktiviteter eller bollspel?: En observationsstudie av barns aktivitetsval på fritidshemmet2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Barn spenderar en stor del av sin tid i olika institutioner som skola och fritidshem. I den delen av vardagen som definieras som fritid gör barn olika val av aktiviteter. Begreppet motorik är i detta sammanhang en aspekt av aktiviteter som är intressant att undersöka. Människors rörelseförmåga och rörelsemönster är den generella definitionen på motorik som delas in i finmotorik och grovmotorik. Tidigare forskning visar att pojkar generellt har en mer utvecklad motorik än flickor och att dessa skillnader blir större ju äldre de blir. Syftet med vår uppsats är att undersöka barns val och deltagande i finmotoriska och grovmotoriska aktiviteter på fritidshemmet. Vi har även tittat på hur faktorer som miljö, verksamhet och pedagogers samspel med barnen och deras aktiviteter relaterar till varandra. Studiens resultat grundar sig i observationer på två olika fritidshem i Sverige. Resultatet har granskats med hjälp av våra teoretiska utgångspunkter, genus och sociokulturellt perspektiv. Det som har framkommit i denna studie är att i valet av aktiviteter som är grovmotoriska eller finmotoriska väljer pojkar generellt grovmotoriska aktiviteter och flickor finmotoriska. Sammanfattningsvis i denna studie framgick det att miljö, pedagogers handlingar, barns intressen, förväntningar, föreställningar, normer och olika grader av strukturer i verksamheten utgör faktorer som kan ha betydelse för barns aktivitetsval på fritidshemmet.

  • Lindström, Per
    Linköping University, Department of Computer and Information Science, Database and information techniques.
    Deep Imitation Learning on Spatio-Temporal Data with Multiple Adversarial Agents Applied on Soccer2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Recently, the availability of high quality and high resolution spatio-temporal data has increased for many sports. This enabled deep analysis of player behaviour and game strategy. This thesis investigates the assumption that game strategy is latent information in tracking data from soccer games and the possibility of modelling player behaviour with deep imitation learning. A possible application would be to perform counterfactual analysis, and switch an observed player in a real sequence, with a simulated player to asses alternative scenarios.

    An imitation learning application is implemented using recurrent neural networks. It is shown that the application is able to learn individual player behaviour and perform rollouts on previously unseen sequences.

  • Naronikar, Aditya
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics.
    Riström, Anton
    Luleå University of Technology, Luleå.
    CFD and Experimental Study of Refuelling and Venting a Fuel System2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In 1999, California Air Resources Board (CARB) implemented a regulation that required all gasoline cars sold in California be fitted with an Onboard Refueling Vapor Recovery System (ORVR). The ORVR system is designed to prevent Volatile Organic Compounds (VOCs) from escaping into the atmosphere during refuelling by storing the gas vapours in a carbon canister. Due to the complex nature of the fuel system, making design changes could have large implications on the ORVR performance of the vehicle. It is therefore desirable to develop a CFD model that can predict the effects of design changes, thereby reducing the need to perform physical tests on each design iteration. This master thesis project was performed at the Fuel Systems department at Volvo Cars in order to help reduce project lead times and product development costs by incorporating CFD as a part of the fuel system development cycle. The CFD results obtained were validated through experimental tests that were also performed as part of this project.

    In this master thesis project, a CFD model was developed to simulate the refuelling of gasoline for a California specification Volvo XC90 with an OPW-11B pump pistol. The model was set up in STAR-CCM+ using the Eulerian Volume of Fluid model for multiphase flow, the RANS realizable k-epsilon turbulence model and the two layer all y+ wall treatment. The effects of the carbon canister were modelled as a porous baffle interface in the simulations where viscous and inertial resistances of the porous media were adjusted to obtain a desired pressure drop across the canister. This method proved to be a suitable simplification for this study. The effects of evaporation as well as a chemical adsorption model for the carbon canister have been excluded from the project due to time limitations.

    It was found that the CFD simulations were in good agreement with the experimental results, especially with respect to capturing the overall behaviour of the fuel system during refuelling. It was found that resolving the flow spatially (and temporally) in the filler pipe was a crucial part in ensuring solver stability. A pressure difference between experiment and simulation was also observed as a consequence of excluding evaporation from the CFD model.

    After the CFD model had been verified and validated, changes to different parts of the fuel system were investigated to observe their effects on ORVR performance. These included changing the recirculation line diameter, changing the carbon canister properties and changing the angle of how the pump pistol was inserted into the capless unit. It was found that the recirculation line diameter is a very sensitive design parameter and increasing the diameter would result in fuel vapour leaking back out into the atmosphere. Similarly, increasing the back pressure by swapping to a different carbon canister would result in the leakage of fuel vapour. On the other hand, insignificant changes in system behaviour were observed when the fuel pistol angle was changed.

  • Müller, Carl
    Linköping University, Department of Management and Engineering, Malmstens Linköping University.
    Basning i påse; STEAM BAG: böja trä med hjälp av en ångpåse och framtagning av produkten STEAM BAG2019Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [sv]

    Basning är en metod där värme och fukt används för att göra träplastiskt och böjbart. Den traditionella metoden att böja trä är att använda en låda eller ett rör och påföra värme och ånga för att mjuka upp träet inför böjning. Böjningen sker sedan utanför basningslådan.

    Det här examensarbetet   att basa trä i en påse och genomföra själva böjningen när träet fortfarande finns kvar i ångpåsen. Här beskrivs framtagandet av den flexibla och lättanvända basningspåsen STEAM BAG, från inledande tester, framtagande av böjmall och kompressionsband till utvärdering och jämförelse med traditionell basning.

    Resultatet av mina tester visa att det är möjligt att förbättra böj metoden traditionell basning med hjälp av ångpåsen då det går att bibehålla värmen och ångan under själva böjningsprocessen.

  • Kenell, Ludwig
    et al.
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Berglund, Stigove
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Effektivitet inom distribuerade team: En fallstudie på sociala och tekniska faktorer inom mjukvaruutveckling2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis presents which factors contribute to efficiency in distributed teams working with software development, and how these factors affect the efficiency of the work process. Working effectively in software development projects is a challenge and the distributed factor, that project members are distributed across more than one office, brings additional complexity. Through the study, we want to help make this complexity more manageable. We have carried out a qualitative case study where we have studied a selected distributed project at a software development company. The empirical data has been collected through semi-structured interviews and analyzed based on identified themes. We have mainly identified social factors, but also some technical factors that contribute to an efficient work process. The factors comprise communication, group identity, mood, culture and norms as well as leadership. They include, among other things, implementing well-adapted communication and documentation, holding frequent meetings, few groupings, common IT tools, promoting social communication, having transparent leadership and the team members having a high level of responsibility. In the conclusion we also describe how the listed factors help to achieve an efficient work processes.

  • Walden, Alice
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Decision traceability in agile software projects: Enabling alignment between changing requirements and product goals2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Agile project management emphasizes flexibility and adapting to change. Embracing change often means that specified requirements get changed, removed or replaced under the course of a software project. Another consequence of the nature of agile projects is that everything that does not directly contribute to the working software gets dropped from the product lifecycle. Traceability – the ability to trace requirements back to their origins and forward to design artifacts, code, and testcases – is one such thing that may be overlooked. At the same time, traceability may be crucial to making sure that the delivered product meets the product goals. This thesis investigates the concept of decision traceability – the ability to trace decisions that relate to the evolution of a software product, as well as the fulfillment of product goals. The purpose of this thesis is to understand the importance of decision traceability in relation to product goals and changing requirements in agile software projects. For this purpose, two research questions were developed. (1) What are the challenges of achieving decision traceability in agile projects? And (2) What are important aspects of achieving decision traceability in agile projects? An interpretive qualitative case study was conducted at an IT-consultancy firm. In the case study, two of the organization’s in-house projects were observed, and six informants were interviewed. In answer to the research questions, seven challenges and six important aspects of achieving decision traceability were identified. A conclusion that can be made from the findings is that other aspects than just well-defined processes– such as team engagement, value perception, and communication – may be essential to achieving decision traceability in agile software projects.

  • Hilm, David
    et al.
    Linköping University, Department of Computer and Information Science, Artificial Intelligence and Integrated Computer Systems.
    Rahim, David
    Linköping University, Department of Computer and Information Science, Artificial Intelligence and Integrated Computer Systems.
    Two-factor Authentication and Digital Signing for an Enterprise System utilizing Yubikey2019Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    The use of a second factor to increase the security of systems is growing and has continued to do so for a long time. This thesis explores options for implementation to use a YubiKey as an authentication method (OTP) as well as for signing digital transactions through a web browser client. Measures of network overhead that occurs in conjunction with Digital Signing of transactions are also disclosed. Our findings show that YubiKey provides flexible and readily available solutions that can be used with only small implementations for OTP authentication. It is also shown that the major concern for implementing a solution for a web browser is to intuitively use certificates stored on a USB-device without installing any plugins or with the use of a third-party application running on the client machine.

  • Smyth, Jonas
    et al.
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Johansson, Simon
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Mikroföretagens strategiska vägval för att tävla på en konkurrensutsatt ITmarknad: En fallstudie om mikroföretagens utmaningar och möjligheter2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The IT market is influenced with constant changes and a highly competitive environment between many different entities. In entrepreneurship, it is often the strategy that determines whether an organization successfully can establish itself and compete within a business area. It is a major challenge to successfully compete as a micro enterprise due to limited supply of resources. The aim of the study was thus to examine how micro enterprises handle strategic choices in order to gain competitive advantage on the IT market, as well as investigate the challenges and opportunities for a micro enterprise in their quest for competitiveness. The study was conducted through a qualitative interpretive case study. Semi-structured interviews were used to collect data from six respondents with different perspectives on entrepreneurship within micro enterprises. The six respondents represent four different micro enterprises and an incubator that offers strategic guidance for newly started IT companies. The result of the study presents that it is fairly easy to start competing within the IT market. It takes few resources to develop a concept and spread it to a wide range of potential customers. As a micro enterprise, the IT market is thus lucrative as it is easy and quick to penetrate. However, the market exists of constant threats from other newcomers. Small companies need a continual inflow of financial resources in order to be able to progress the business, which leads to high demands on the ability to quickly establish itself on the market. Large organizations can hardly be an efficient customer for micro enterprises because of their immobility. Strategy is generally handled scarcely within micro enterprises. The IT markets uncertainty and the constant changes makes it hard for micro enterprises to formalize pronounced strategies in the long term. It does however exist a strategic way of thinking within micro enterprises, although on an informal and improvisational level. On the other hand, strategies for both differentiation and segmentation are sought, sometimes in combination with each other. Micro enterprises in the IT market is driven by entrepreneurship and innovation, which results in the development of differentiated products and services. In a constantly changing market, micro enterprises have great opportunities to achieve flexibility and rapid mobility in a different manner compared to larger companies. Hence, micro enterprises can quickly react and adapt to the ever-changing world of IT.

  • Brandt, Daniel
    et al.
    Linköping University, Department of Computer and Information Science.
    Fasth, Frida
    Linköping University, Department of Computer and Information Science.
    Gustavsson, Adam
    Linköping University, Department of Computer and Information Science.
    Janfalk, Elsa
    Linköping University, Department of Computer and Information Science.
    Kimiaei, Felix
    Linköping University, Department of Computer and Information Science.
    Lindholm, Victor
    Linköping University, Department of Computer and Information Science.
    Palmlund, Victor
    Linköping University, Department of Computer and Information Science.
    Swensson, Styrbjörn
    Linköping University, Department of Computer and Information Science.
    En undersökning av on-site-faktorers påverkan på en e-handelsplattform2019Independent thesis Basic level (degree of Bachelor), 12 credits / 18 HE creditsStudent thesis
    Abstract [en]

    As a result of trends identified in the report and marketing plan, the importance of a search engine optimized platform for e-commerce is established. In order to further examine the implementation of such, a website was constructed with this purpose in mind. The of said website was designed based on user stories which in their turn partly came from competitor's websites and partly from preference. In order to optimize the website for search engines, four established factors were optimized to the best of the group's ability. These factors were responsivity, custom 404-page, sitemap and keywords. Testing these factors against Google, the tests were ran partly through the search engine itself and partly through the third-party programmes WebSite Auditor and SERPROBOT. In accordance with expectations, the keywords had a considerable effect on the acquired results, but the remaining factors had nothing more than a marginal contribution; this was not expected. The experiment had many sources of error and and low reliability, cheifly on account of the chosen instruments for measure and a statistical uncertainty as a result of few observations. The conclusion made is that keywords have a greater effect than the other evaluated factors.

  • Bouilloux-Lafont, Antoine
    et al.
    Linköping University, Department of Management and Engineering, Machine Design.
    Noya Pozo, Rubén
    Development of Acoustic Simulations using Parametric CAD Models in COMSOL2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    With constantly changing regulations on emissions, heavy commercial vehicles manufacturershave to adapt for their products to preserve their quality while meetingthese new requirements. Over the past decades, noise emissions have become a greatconcern and new stricter laws demand companies to decrease their vehicle pass-bynoise target values.To address the requirements from different disciplines, Scania follows a simulationdriven design process to develop new concept models EATS. The collaboration amongengineers from different fields is thereby necessary in order to obtain higher performancesilencers. However, the pre-processing step in terms of acoustic simulationsis time-consuming, which can slow the concept development process.In this thesis, a new method was introduced to automate the pre-processing of silenceracoustic models and allow for design optimisation based on acoustic performanceresults. A common Scania product study case was provided to several theseswithin the NXD organisation. The collaboration among the master thesis workersaimed to demonstrate the benefits of KBE and MDO and how they can be integratedwithin Scania’s current concept development and product introduction processes.The performed work was divided in the following steps: data collection, methoddevelopment and concluding work. The first step consisted in gathering sufficientknowledge by conducting a thorough literature review and interviews. Then, an initialmethod was formulated and tested on a simplified silencer model. Once approvedand verified, the method was applied to the study case EATS.The study case showed that a complex product can have its acoustic pre-processingstep automated by ensuring a good connectivity among the required software anda correct denomination of the geometrical objects involved in the simulations. Themethod investigated how morphological optimisations can be performed at bothglobal and local levels to enhance the transmission loss of a silencer. Besides optimisingthe acoustic performance of the models, the method allowed the identificationof correlations and inter-dependencies among their design variables and ouput parameters.

  • Eriksson, Hanna
    Linköping University, Department of Management and Engineering, Machine Design.
    On-Board Data Aquisition System: Conceptual Design of an Airdrop Tracking System2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis is, on behalf of Saab AB, a pre-study of possible on-board solutions for position measuring during store separation tests aimed for the test and evaluation of JAS 39 Gripen. The purpose is to replace the present ground-based system in order to achieve more effective trials regarding time and economy.

    Three different concept development methodologies were investigated in order to find the most suitable one for this thesis. Those were merged into one adapted methodology containing the following phases; \textit{Planning}, \textit{Function Analysis}, \textit{Concept Generation} and \textit{Concept Evaluation}.

    The work progressed as the methodology states, and the highest amount of work was dedicated to the Planning phase. The requirements and desiderata for the system were produced with an agile process, resulting in the Construction Specification List that eventually became the basis for the Concept Generation phase.

    Knowledge about the technical theory needed to solve the problem was obtained in parallel with the Function Analysis and Concept Generation. The most adaptable techniques to measure position were found out to be with the use of the Global Positioning System (GPS) or Inertial Navigation System (INS).

    After an extensive work with the Concept Generation in parallel with a continuously updated Construction Specification List, three concepts were developed. One concept is based on GPS, the second one on INS and the third one is a combination of GPS and INS. All three concepts shares the same telemetry system and casing, which fulfills the requirement of simple installation and possibility to install in different stores.

    In the final phase, Concept Evaluation, a comparison between the concepts was performed. Advantages and disadvantages was listed and the fulfillment of requirements was investigated. All three concepts were handed over to Saab in order to let them decide which concept(s) to further develop.

  • Palmé, Anna
    et al.
    Fitzgerald, Heli
    Botany, Finnish Museum of Natural History, University of Helsinki, Finland.
    Weibull, Jens
    Swedish University of Agricultural Sciences.
    Bjureke, Kristina
    Natural History Museum, Norway.
    Eisto, Kaija
    Endresen, Dag
    Geo-Ecology Research Group, Natural History Museum, Oslo, Norway.
    Hagenblad, Jenny
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Hyvärinen, Marko
    Botany, University of Helsinki, Finland.
    Kiviharju, Elina
    Natural Resources Institute Finland (Luke), Helsinki, Finland.
    Lund, Birgitte
    Rasmussen, Morten
    Þorbjörnsson, Hjörtur
    Reykjavík Botanic Garden, Reykjavik, Iceland.
    Nordic Crop Wild Relative conservation: A report from two collaborative projects 2015–20192019Report (Other academic)
    Abstract [en]

    The report summarizes results from a cooperation among all the Nordic countries during the period 2015 – 2019 (two projects). The work has focused on the conservation of Crop Wild Relatives (CWR), i.e. wild plant species closely related to crops. They are of special importance to humanity since traits of potential value for food security and climate change adaptation can be transferred from CWR into crops. The projects represent the first joint action on the Nordic level regarding in situ conservation of CWR. Substantial progress has been made regarding CWR conservation planning, including development of a Nordic CWR checklist and identification of suitable sites for CWR conservation. A set of recommended future actions was developed, with the most important one being initiation of active in situ conservation of CWR in all Nordic countries.

  • Public defence: 2019-09-13 13:15 Ada Lovelace, B-huset, Linköping
    Ghasemi Zinatabadi, Fatemeh
    Linköping University, Department of Mathematics, Computational Mathematics. Linköping University, Faculty of Science & Engineering.
    Stability, dual consistency and conservation of summation-by-parts formulations for multiphysics problems2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis, we consider the numerical solution of initial boundary value problems (IBVPs). Boundary and interface conditions are derived such that the IBVP under consideration is well-posed. We also study the dual problem and the related dual boundary/interface conditions. Once the continuous problem is analyzed, we use finite difference operators with the Summation- By-Parts property (SBP) and a weak boundary/interface treatment using the Simultaneous-Approximation-Terms (SAT) technique to construct high-order accurate numerical schemes. We focus in particular on stability, conservation and dual consistency. The energy method is used as our main analysis tool for both the continuous and numerical problems.

    The contributions of this thesis can be divided into two parts. The first part focuses on the coupling of different IBVPs. Interface conditions are derived such that the continuous problem satisfy an energy estimate and such that the discrete problem is stable. In the first paper, two hyperbolic systems of different size posed on two domains are considered. We derive the dual problem and dual interface conditions. It is also shown that a specific choice of penalty matrices leads to dual consistency. As an application, we study the coupling of the Euler and wave equations. In the fourth paper, we examine how to couple the compressible and incompressible Navier-Stokes equations. In order to obtain a sufficient number of interface conditions, the decoupled heat equation is added to the incompressible equations. The interface conditions include mass and momentum balance and two variants of heat transfer. The typical application in this case is the atmosphere-ocean coupling.

    The second part of the thesis focuses on the relation between the primal and dual problem and the relation between dual consistency and conservation. In the second and third paper, we show that dual consistency and conservation are equivalent concepts for linear hyperbolic conservation laws. We also show that these concepts are equivalent for symmetric or symmetrizable parabolic problems in the fifth contribution. The relation between the primal and dual boundary conditions for linear hyperbolic systems of equations is investigated in the sixth and last paper. It is shown that for given well-posed primal/dual boundary conditions, the corresponding well-posed dual/primal boundary conditions can be obtained by a simple scaling operation. It is also shown how one can proceed directly from the well-posed weak primal problem to the well-posed weak dual problem.  

    List of papers
    1. Coupling Requirements for Multiphysics Problems Posed on Two Domains
    Open this publication in new window or tab >>Coupling Requirements for Multiphysics Problems Posed on Two Domains
    2017 (English)In: SIAM Journal on Numerical Analysis, ISSN 0036-1429, E-ISSN 1095-7170, Vol. 55, no 6, p. 2885-2904Article in journal (Refereed) Published
    Abstract [en]

    We consider two hyperbolic systems in first order form of different size posed on two domains. Our ambition is to derive general conditions for when the two systems can and cannot be coupled. The adjoint equations are derived and well-posedness of the primal and dual problems is discussed. By applying the energy method, interface conditions for the primal and dual problems are derived such that the continuous problems are well posed. The equations are discretized using a high order finite difference method in summation-by-parts form and the interface conditions are imposed weakly in a stable way, using penalty formulations. It is shown that one specic choice of penalty matrices leads to a dual consistent scheme. By considering an example, it is shown that the correct physical coupling conditions are contained in the set of well posed coupling conditions. It is also shown that dual consistency leads to superconverging functionals and reduced stiffness.

    Place, publisher, year, edition, pages
    Society for Industrial and Applied Mathematics, 2017
    Keywords
    well posed problems, high order finite diffrences, stability, summation-by-parts, weak interface conditions, dual consistency, stiffness, superconvergence
    National Category
    Computational Mathematics
    Identifiers
    urn:nbn:se:liu:diva-143261 (URN)10.1137/16M1087710 (DOI)000418663500015 ()
    Available from: 2017-11-28 Created: 2017-11-28 Last updated: 2019-08-01Bibliographically approved
    2. On the relation between conservation and dual consistency for summation-by-parts schemes
    Open this publication in new window or tab >>On the relation between conservation and dual consistency for summation-by-parts schemes
    2017 (English)In: Journal of Computational Physics, ISSN 0021-9991, E-ISSN 1090-2716, Vol. 344, p. 3p. 437-439Article in journal (Refereed) Published
    Abstract [en]

    n/a

    Publisher
    p. 3
    Keywords
    Initial boundary value problems Summation-by-parts Conservation, Dual consistent, Multi-block, Multi-element
    National Category
    Mathematics
    Identifiers
    urn:nbn:se:liu:diva-137545 (URN)10.1016/j.jcp.2017.04.072 (DOI)000402481300021 ()
    Note

    Classified in the journal as "Short note"

    Available from: 2017-05-21 Created: 2017-05-21 Last updated: 2019-08-01
    3. Corrigendum to “On the relation between conservation and dual consistency for summation-by-parts schemes”[J. Comput. Phys. 344 (2017) 437–439]
    Open this publication in new window or tab >>Corrigendum to “On the relation between conservation and dual consistency for summation-by-parts schemes”[J. Comput. Phys. 344 (2017) 437–439]
    2018 (English)In: Journal of Computational Physics, ISSN 0021-9991, E-ISSN 1090-2716, Vol. 360, p. 247-247Article in journal (Refereed) Published
    Place, publisher, year, edition, pages
    Academic Press, 2018
    National Category
    Mathematics
    Identifiers
    urn:nbn:se:liu:diva-145718 (URN)10.1016/j.jcp.2018.02.046 (DOI)000428966300014 ()
    Available from: 2018-03-19 Created: 2018-03-19 Last updated: 2019-08-01Bibliographically approved
    4. An energy stable coupling procedure for the compressible and incompressible Navier-Stokes equations
    Open this publication in new window or tab >>An energy stable coupling procedure for the compressible and incompressible Navier-Stokes equations
    2019 (English)In: Journal of Computational Physics, ISSN 0021-9991, E-ISSN 1090-2716, Vol. 396, p. 280-302Article in journal (Refereed) Epub ahead of print
    Abstract [en]

    The coupling of the compressible and incompressible Navier-Stokes equations is considered. Our ambition is to take a first step towards a provably well posed and stable coupling procedure. We study a simplified setting with a stationary planar interface and small disturbances from a steady background flow with zero velocity normal to the interface. The simplified setting motivates the use of the linearized equations, and we derive interface conditions such that the continuous problem satisfy an energy estimate. The interface conditions can be imposed both strongly and weakly. It is shown that the weak and strong interface imposition produce similar continuous energy estimates. We discretize the problem in time and space by employing finite difference operators that satisfy a summation-by-parts rule. The interface and initial conditions are imposed weakly using a penalty formulation. It is shown that the results obtained for the weak interface conditions in the continuous case, lead directly to stability of the fully discrete problem.

    Keywords
    Compressible fluid, Incompressible fluid, Navier-Stokes equations, Energy estimate, Interface conditions, Stability
    National Category
    Mathematics
    Identifiers
    urn:nbn:se:liu:diva-159116 (URN)10.1016/j.jcp.2019.07.022 (DOI)
    Available from: 2019-07-29 Created: 2019-07-29 Last updated: 2019-08-01
    5. On conservation and dual consistency for summation-by-parts based approximations of parabolic problems
    Open this publication in new window or tab >>On conservation and dual consistency for summation-by-parts based approximations of parabolic problems
    2019 (English)Report (Other academic)
    Abstract [en]

    We consider the coupling of parabolic problems discretized using difference operators on summation-by-parts (SBP) form with interface conditions imposed weakly. In, it was shown that conservation and dual consistency are equivalent concepts for linear conservation laws. Here, we show that these concepts are equivalent also for symmetric or symmetrizable parabolic problems, exemplified by the heat equation. We rewrite the heat equation as first order system as in the local discontinuous Galerkin method and show the equivalence of dual consistency and conservation for both the first and second order forms.

    Place, publisher, year, edition, pages
    Linköping: Linköping University Electronic Press, 2019. p. 9
    Series
    LiTH-MAT-R, ISSN 0348-2960 ; 2019:5
    National Category
    Computational Mathematics Mathematics
    Identifiers
    urn:nbn:se:liu:diva-158903 (URN)LiTH-MAT-R--2019/05--SE (ISRN)
    Available from: 2019-07-17 Created: 2019-07-17 Last updated: 2019-08-12Bibliographically approved
    6. The Relation Between Primal and Dual Boundary Conditions for Hyperbolic Systems of Equations
    Open this publication in new window or tab >>The Relation Between Primal and Dual Boundary Conditions for Hyperbolic Systems of Equations
    2019 (English)Report (Other academic)
    Abstract [en]

    In this paper we study boundary conditions for linear hyperbolic systems of equations and the corresponding dual problems. In particular, we show that the primal and dual boundary conditions are related by a simple scaling relation. It is also shown that the weak dual problem can be derived directly from the weak primal problem.

    Based on the continuous analysis, we discretize and perform computations with a high-order finite difference scheme on summation-by-parts form with weak boundary conditions. It is shown that the results obtained in the continuous analysis lead directly to stability results for the primal and dual discrete problems. Numerical experiments corroborate the theoretical results.

    Place, publisher, year, edition, pages
    Linköping: Linköping University Electronic Press, 2019. p. 22
    Series
    LiTH-MAT-R, ISSN 0348-2960 ; 2019:6
    Keywords
    Hyperbolic systems, boundary conditions, primal problem, dual problem, well-posedness, dual consistency
    National Category
    Computational Mathematics Mathematics
    Identifiers
    urn:nbn:se:liu:diva-158904 (URN)LiTH-MAT-R--2019/06--SE (ISRN)
    Available from: 2019-07-17 Created: 2019-07-17 Last updated: 2019-08-12Bibliographically approved
  • Public defence: 2019-09-13 10:15 Planck, Fysikhuset, Linköping
    Engberg, David L. J.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Atom Probe Tomography of Hard Nitride and Boride Thin Films2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Hard ceramic thin films, including TiSiN, ZrAlN, ZrB2, and ZrTaB2, with applications for wear-resistant coatings, have been studied using atom probe tomography and correlated with several other analytical techniques, including X-ray diffraction, electron microscopy, and elastic recoil detection analysis. Outstanding obstacles for quantitative atom probe tomography of ceramic thin films have been surmounted.

    Mass spectral overlaps in TiSiN, which make 28Si indistinguishable from 14N, was resolved by isotopic substitution with 15N, and the nanostructural distribution of elements was thus revealed in 3-D, which enabled the identification of additional structural elements within the nanostructured Ti0.81Si0.1915N film. Improvements to the growth model of TiSiN by cathodic arc deposition was suggested.

    A self-organized nanolabyrinthine structure of ZrAlN, consisting of standing lamellae of fcc-ZrN and hexagonal AlN, was investigated with focus on the onset and limits of the self-organization. The local crystallographic orientational relationships were (001)ZrN || (0001)AlN and <110>ZrN || <2-1-10>AlN. Close to the MgO substrates, a smooth transition region was formed, going from segregated and disordered to the self-organized nanolabyrinthine structure. With increased growth temperature, coarse (111)-oriented ZrN grains occasionally precipitated and locally replaced the nanolabyrinthine structure. Significant local magnification effects rendered the Zr and N signals unusable, thereby inhibiting quantitative compositional analysis of the constituent phases, but the nanostructure was resolved using the Al signal.

    Ceramic materials are often affected by correlated evaporation, which can result in losses due to the detector dead-time/space. A compositional correction procedure was suggested, tested against an established procedure, and applied to ZrB2. The correction was found to be less dependent on the isotope abundances and background correction compared to the established procedure. While losses due to dead-time/space occur in atom probe tomography of all materials, the correlative field evaporation behavior of ceramics significantly increases the compositional error. The evaporation behavior of ZrB2 was therefore thoroughly investigated and evidence of preferential retention, correlated evaporation, and inhomogeneous field distributions at a low-index pole was presented. The high mass resolution, relatively low multiple events percentage, and quality of the co-evaporation correlation data was partly attributed to the crystal structure and film orientation, which promoted a layer-by-layer field evaporation.

    The evaporation behavior of the related ZrTaB2 films was found to be similar to that of ZrB2. The distribution of Ta in relation to Zr was investigated, showing that the column boundaries were both metal- and Ta-rich, and that there was a significant amount of Ta in solid solution within the columns.

    In addition, an instrumental artefact previously not described in atom probe tomography was found in several of the materials investigated in this thesis. The artefact consists of high-density lines along the analysis direction, which cannot be related to pole artefacts. The detection system of the atom probe was identified as the cause, because the artefact patterns on detector histograms coincided with the structure of the microchannel plate. Inconsistencies in the internal boundaries of the microchannel plate multifibers from the manufacturing process can influence the signal to the detector and locally increase the detection efficiency in a pattern characteristic to the microchannel plate in question.

    Altogether, this thesis shows that atom probe tomography of nitride and boride thin films is burdened by several artefacts and distortions, but that relevant material outcomes can nevertheless be achieved by informed choices of film isotopic constituents and analytical parameters, exclusion of heavily distorted regions (such as pole artefacts), and the use of compositional correction procedures when applicable.

    List of papers
    1. Resolving Mass Spectral Overlaps in Atom Probe Tomography by Isotopic Substitutions: Case of TiSi15N
    Open this publication in new window or tab >>Resolving Mass Spectral Overlaps in Atom Probe Tomography by Isotopic Substitutions: Case of TiSi15N
    Show others...
    2018 (English)In: Ultramicroscopy, ISSN 0304-3991, E-ISSN 1879-2723, Vol. 184, p. 51-60Article in journal (Refereed) Published
    Abstract [en]

    Mass spectral overlaps in atom probe tomography (APT) analyses of complex compounds typically limit the identification of elements and microstructural analysis of a material. This study concerns the TiSiN system, chosen because of severe mass-to-charge-state ratio overlaps of the 14N+ and 28Si2+ peaks as well as the 14N and 28Si2+ peaks. By substituting 14N with 15N, mass spectrum peaks generated by ions composed of one or more N atoms will be shifted toward higher mass-to-charge-state ratios, thereby enabling the separation of N from the predominant Si isotope. We thus resolve thermodynamically driven Si segregation on the nanometer scale in cubic phase Ti1-xSix15N thin films for Si contents 0.08 ≤ x ≤ 0.19 by APT, as corroborated by transmission electron microscopy. The APT analysis yields a composition determination that is in good agreement with energy dispersive X-ray spectroscopy and elastic recoil detection analyses. Additionally, a method for determining good voxel sizes for visualizing small-scale fluctuations is presented and demonstrated for the TiSiN system.

    Place, publisher, year, edition, pages
    Elsevier, 2018
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-122721 (URN)10.1016/j.ultramic.2017.08.004 (DOI)000415650200007 ()28850866 (PubMedID)
    Note

    Funding Agencies:VINN Excellence Center on Functional Nanoscale Materials (FunMat) [2007-00863]; Swedish Research Council (VR) project [2013-4018]; Swedish Government Strategic Research Area Grant in Materials Science (Grant SFO Mat-LiU) on Advanced Functional Materials [2009-00971]; Knut and Alice Wallenberg Project Isotope

    Available from: 2015-11-18 Created: 2015-11-18 Last updated: 2019-08-01Bibliographically approved
    2. Self-organized Nanostructuring in Zr0.64Al0.36N Thin Films Studied by Atom Probe Tomography
    Open this publication in new window or tab >>Self-organized Nanostructuring in Zr0.64Al0.36N Thin Films Studied by Atom Probe Tomography
    Show others...
    2016 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, p. 233-238Article in journal (Refereed) Published
    Abstract [en]

    We have applied atom probe tomography (apt) to analyze the selforganized structure of wear-resistant Zr0.64Al0.36N thin films grown by magnetron sputtering. Transmission electron microscopy shows that these films grow as a two-dimensional nanocomposite, consisting of interleaved lamellae in a labyrinthine structure, with a size scale of ∼ 5 nm. The structure was recovered in the Al apt signal, while the Zr and N data lacked structural information due to severe local magnification effects. The onset of the self-organized growth was observed to occur locally by nucleation, at 5-8 nm from the MgO substrate, after increasing Zr-Al compositional fluctuations. Finally, it was observed that the self-organized growth mode could be perturbed by renucleation of ZrN.

    Place, publisher, year, edition, pages
    Elsevier, 2016
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-84258 (URN)10.1016/j.tsf.2016.07.034 (DOI)000381939700037 ()
    Note

    Funding agencies: VINN Excellence Center on Functional Nanoscale Materials; Swedish Research Council; Swedish Government Strategic Faculty Grant in Materials Science (SFO Mat-LiU) at Linkoping University; Swedish Governmental Agency for Innovation Systems (Vinnova) [2011-0

    Vid tiden för disputationen förelåg publikationen som manuskript

    Available from: 2012-10-03 Created: 2012-10-03 Last updated: 2019-08-02Bibliographically approved
    3. Strategy for simultaneously increasing both hardness and toughness in ZrB2-rich Zr1-xTaxBy thin films
    Open this publication in new window or tab >>Strategy for simultaneously increasing both hardness and toughness in ZrB2-rich Zr1-xTaxBy thin films
    Show others...
    2019 (English)In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 37, no 3, article id 031506Article in journal (Refereed) Published
    Abstract [en]

    Refractory transition-metal diborides exhibit inherent hardness. However, this is not always sufficient to prevent failure in applications involving high mechanical and thermal stress, since hardness is typically accompanied by brittleness leading to crack formation and propagation. Toughness, the combination of hardness and ductility, is required to avoid brittle fracture. Here, the authors demonstrate a strategy for simultaneously enhancing both hardness and ductility of ZrB2-rich thin films grown in pure Ar on Al2O3(0001) and Si(001) substrates at 475 degrees C. ZrB2.4 layers are deposited by dc magnetron sputtering (DCMS) from a ZrB2 target, while Zr1-xTaxBy alloy films are grown, thus varying the B/metal ratio as a function of x, by adding pulsed high-power impulse magnetron sputtering (HiPIMS) from a Ta target to deposit Zr1-xTaxBy alloy films using hybrid Ta-HiPIMS/ZrB2-DCMS sputtering with a substrate bias synchronized to the metal-rich portion of each HiPIMS pulse. The average power P-Ta (and pulse frequency) applied to the HiPIMS Ta target is varied from 0 to 1800W (0 to 300 Hz) in increments of 600W (100 Hz). The resulting boron-to-metal ratio, y = B/(Zr+Ta), in as-deposited Zr1-xTaxBy films decreases from 2.4 to 1.5 as P-Ta is increased from 0 to 1800W, while x increases from 0 to 0.3. A combination of x-ray diffraction (XRD), glancing-angle XRD, transmission electron microscopy (TEM), analytical Z-contrast scanning TEM, electron energy-loss spectroscopy, energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, and atom-probe tomography reveals that all films have the hexagonal AlB2 crystal structure with a columnar nanostructure, in which the column boundaries of layers with 0 amp;lt;= x amp;lt; 0.2 are B-rich, whereas those with x amp;gt;= 0.2 are Ta-rich. The nanostructural transition, combined with changes in average column widths, results in an similar to 20% increase in hardness, from 35 to 42 GPa, with a simultaneous increase of similar to 30% in nanoindentation toughness, from 4.0 to 5.2MPa root m. Published by the AVS.

    Place, publisher, year, edition, pages
    A V S AMER INST PHYSICS, 2019
    National Category
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:liu:diva-159001 (URN)10.1116/1.5093170 (DOI)000472182400035 ()
    Note

    Funding Agencies|Swedish Research Council VR [2014-5790, 2018-03957, 642-2013-8020]; Knut and Alice Wallenbergs foundation [KAW 2015.0043]; VINNOVA [2018-04290]; Aforsk Foundation [16-359]; Carl Tryggers Stiftelse [CTS 15: 219, CTS 17: 166, CTS 14: 431]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO Mat LiU) [2009 00971]

    Available from: 2019-07-19 Created: 2019-07-19 Last updated: 2019-08-01