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  • 51.
    Andersson, Gunnel
    et al.
    FoU Sodertorn, Sweden.
    Ellegård, Kajsa
    Linköping University, Department of Thematic Studies, Technology and Social Change. Linköping University, Faculty of Arts and Sciences.
    Bulow, Per
    Jonkoping Univ, Sweden.
    Denhov, Anne
    Stockholm Univ, Sweden.
    Vrotsou, Katerina
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Stefansson, Claes-Goran
    Stockholm Univ, Sweden.
    Topor, Alain
    Stockholm Univ, Sweden.
    A longitudinal study of men and women diagnosed with psychosis: trajectories revealing interventions in a time-geographic framework2022In: GeoJournal, ISSN 0343-2521, E-ISSN 1572-9893, Vol. 87, no 4, p. 2423-2440Article in journal (Refereed)
    Abstract [en]

    The living conditions for persons with severe mental illness have undergone substantial change in Sweden as well as in the rest of the Western world due to the downsizing of inpatient care and the development of community-based interventions. However, there is a lack of knowledge concerning the "trajectories of interventions" in this new, fragmented, institutional landscape. The aim of the study was to explore types of interventions and when they occur in a 10-year follow-up of 437 women and men diagnosed with psychosis for the first time. Based on registers and using a timegeographic visualization method, the results showed a great diversity of trajectories and differences between sexes. The aggregate picture revealed that over the 10-year period there were considerable periods with no interventions for both men and women. Furthermore, institutional interventions more commonly occurred among women but appeared for longer periods among men. Community-based interventions declined among women and increased among men during the period.

  • 52.
    Andersson, Gunnel
    et al.
    FoU Sodertorn, Sweden.
    Vrotsou, Katerina
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Denhov, Anne
    Stockholm Univ, Sweden.
    Topor, Alain
    Stockholm Univ, Sweden; Univ Agder, Norway.
    Bulow, Per
    Jonkoping Univ, Sweden; Forens Psychiat Reg Clin, Sweden.
    Ellegård, Kajsa
    Linköping University, Department of Thematic Studies, Technology and Social Change. Linköping University, Faculty of Arts and Sciences.
    A diversity of patterns: 10-year trajectories of men and women diagnosed with psychosis for the first time. A time-geographic approach2020In: Moravian Geographical Reports, ISSN 1210-8812, E-ISSN 2199-6202, Vol. 28, no 4, p. 283-298Article in journal (Refereed)
    Abstract [en]

    People with severe mental illness face a different interventional landscape compared to some decades ago, when mental hospitals were dominant, in Sweden as well as in the rest of the Western world. The aim of the research reported in this article was to follow men and women diagnosed with psychosis for the first time over a 10-year period, and to explore what interventions they experienced. The interventions, here defined as "spheres", were either community-based or institutional. A third sphere represents no interventions. Based on data from registers and using a time-geographic approach, the individuals were visualised as 10-year trajectories where their transitions between the different spheres were highlighted. The results show a great diversity of trajectories. Two main categories were detected: two-spheres (community-based and no interventions) and three-spheres (adding institutional interventions). One third of the population experienced only community-based interventions, with a higher proportion of men than women. Consequently, more women had institutional experience. Two sub-categories reveal trajectories not being in the interventional sphere in a stepwise manner before the 10th year, and long-term trajectories with interventions in the 10th year. The most common pattern was long-term trajectories, embracing about half of the population, while one-fifth left the institutional sphere before the 5th year.

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  • 53.
    Andersson, Johanna
    et al.
    Linköping University, Department of Social and Welfare Studies, Learning, Aesthetics, Natural science. Linköping University, Faculty of Educational Sciences.
    Löfgren, Ragnhild
    Linköping University, Department of Social and Welfare Studies, Learning, Aesthetics, Natural science. Linköping University, Faculty of Educational Sciences.
    Tibell, Lena
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Educational Sciences.
    What’s in the body? Children’s annotated drawings2020In: Journal of Biological Education, ISSN 0021-9266, E-ISSN 2157-6009, no 2, p. 176-190Article in journal (Refereed)
    Abstract [en]

    This paper presents a study of children’s ideas of the body’s internal structure. Children between four and 13 years (N = 170) individually produced drawings. During each drawing session the children explained their drawings to a facilitator and added written labels either by them- selves or, if they were too young to write, with the facilitator’s help. The results provide an updated comprehensive picture of children in differ- ent age groups and their views on the internal structure of the body. The type and numbers of organs drawn are similar to those documented in previous studies. However, in comparison to recent studies, the children drew more organs, the brain was indicated almost as often as the heart, and the Valentine heart was frequently used as a symbol. In contrast with previous research, children drew connections between organs. This result calls for caution regarding conclusions made from decontextua- lized questions. The importance of providing children with the opportu- nity to clarify their drawings is emphasised since it otherwise becomes a question of the researcher’s interpretation. The connections they draw, and explanations they give to their drawings, have interesting implica- tions for understanding children’s ideas, and hence both for teaching and learning and for science education research.

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  • 54.
    Andersson, Johanna
    et al.
    Linköping University, Department of Social and Welfare Studies, Learning, Aesthetics, Natural science. Linköping University, Faculty of Educational Sciences.
    Tibell, Lena
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Educational Sciences.
    Exploring childrens' views of what's inside the body2012Conference paper (Refereed)
    Abstract [en]

    The importance of living a healthy life in an everyday context is promoted in schools and preschools. The discussion often focuses on what food is healthy, and that one should eat enough but not too much. The connection between food and beverages and their role in the body is seldom discussed. Students’ ideas about how the human body functions have been investigated in several studies but few have focused on young children. In this study, we investigate young children’s conceptions related to this topic and how their ideas develop. Seventy-nine pre- and primary school children, aged 4-11, participated in individual focus interviews wherein the children were asked to draw and explain their understanding. Our results confirm several findings observed by other workers. However, in contrast with earlier studies, 10 of seventeen 4-5 year-old children indicated the stomach, and more than half of those children described how food can be utilized in the body to extract energy. Furthermore, the brain was among the most commonly mentioned organs cross all age groups. Interestingly, the level of expertise varied and did not covariate with age. For example, five of eight of the 4 year-old children draw 5-8 organs, while a single 10 year-old child could only mention three. Similarly, two of thirteen 7-year old children provided an almost completely correct description of the digestive tract and its function, while most of the older children expressed a much less developed understanding. The results reflect the wide range of different conceptual ideas that teachers confront in a day-to-day classroom context.

  • 55.
    Andersson, Johanna
    et al.
    Linköping University, Department of Social and Welfare Studies, Learning, Aesthetics, Natural science. Linköping University, Faculty of Educational Sciences.
    Tibell, Lena A.E.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Educational Sciences.
    Children's reasoning and representations about living and non-living things2013Conference paper (Refereed)
    Abstract [en]

    Understanding of the concept ‘life’ and what characterise ‘living things’ is important as a foundation for learning in biology. In a more general view, this understanding can make children develop awareness, respect and responsibility for life as members of a society and in decision making for sustainable development. The present pilot study aim to investigate 5-6 year old pre-school children’s reasoning and representations about living and nonliving things. In cognitive developmental research, the concept of life is well investigated but, questions still remain regarding how children reason around and represent these concepts. Previous research has found that children have difficulties in including plants as living things. Moreover, it is found that young children include e.g. the sun, clouds and rocks as living things. The methods that have been used are often quantitative and use picture-cards with different objects for the children to categorize. In the present pilot study a modified methodology was applied. Children’s drawings of what they consider as living and non-living were collected and picture-cards were used as point of departure for reasoning. In interviews the children were encouraged to explain and express their ideas. The drawings and the cards mainly worked as a meaning making tool for the children. Results from the study will be presented and discussed. 

  • 56.
    Andersson, Kaisa
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Björk, Carolina
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Specific conditions for marketing of non-profit organizations conducting fundraising2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Många ideella organisationer behöver bidrag och stöd för att kunna bedriva sitt arbete. Därmed blir det viktigt att vara synliga och sticka ut från mängden för att få människors stöd. Syftet med denna studie är att undersöka specifika förutsättningar för marknadsföring av ideella organisationer som bedriver insamling i Sverige. Genom kvalitativa intervjuer undersöktes hur väl Barncancerfondens och Kvinna till Kvinnas uppfattningar överensstämmer med teorier som finns inom området. Slutsatser som överensstämde med litteraturen var att ideella organisationer ofta har som mål att nå en mycket bred publik eller till och med hela allmänheten. Men studien visar även att Barncancerfonden och Kvinna till Kvinna arbetar strategiskt med målgrupper för att rikta insamling och informationsarbete, trots att det finns en vilja att nå ut brett. Inom ideella organisationer är det även svårt att modifiera budskapet, eftersom det måste spegla verksamheten. Hur organisationen påverkas av detta beror delvis på vilken typ av ämne som organisationen berör eftersom det med ett intresseväckande ämne är lättare att nå ut. En annan specifik förutsättning är att gåvor ofta är en osynlig handling som gynnar någon annan. Avsaknaden av produkt nämns av organisationerna som något marknadsföringen måste bemöta, vilket kan ske på olika sätt. Ideella verksamheter normalt uppfattas ha ett gott syfte vilket gör allmänheten mer mottaglig för budskapen.

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  • 57.
    Andersson, Magnus
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Lantz, Jonas
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Ebbers, Tino
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Quantitative Assessment of Turbulence and Flow Eccentricity in an Aortic Coarctation - Impact of Virtual Interventions2015In: Cardiovascular Engineering and Technology, ISSN 1869-408X, E-ISSN 1869-4098, Vol. 6, no 6, p. 281-293Article in journal (Refereed)
    Abstract [en]

    Turbulence and flow eccentricity can be measured by magnetic resonance imaging (MRI) and may play an important role in the pathogenesis of numerous cardiovascular diseases. In the present study, we propose quantitative techniques to assess turbulent kinetic energy (TKE) and flow eccentricity that could assist in the evaluation and treatment of stenotic severities. These hemodynamic parameters were studied in a pre-treated aortic coarctation (CoA) and after several virtual interventions using computational fluid dynamics (CFD), to demonstrate the effect of different dilatation options on the flow field. Patient-specific geometry and flow conditions were derived from MRI data. The unsteady pulsatile flow was resolved by large eddy simulation (LES) including non-Newtonian blood rheology. Results showed an inverse asymptotic relationship between the total amount of TKE and degree of dilatation of the stenosis, where turbulent flow proximal the constriction limits the possible improvement by treating the CoA alone. Spatiotemporal maps of TKE and flow eccentricity could be linked to the characteristics of the jet, where improved flow conditions were favored by an eccentric dilatation of the CoA. By including these flow markers into a combined MRI-CFD intervention framework, CoA therapy has not only the possibility to produce predictions via simulation, but can also be validated pre- and immediate post treatment, as well as during follow-up studies.

  • 58.
    Andersson, Magnus
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Lantz, Jonas
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    NON-INVASIVE INTERVENTION PLANNING OF STENOTIC FLOWS USING SCALE-RESOLVED IMAGE-BASED COMPUTATIONAL FLUID DYNAMICS2013Conference paper (Refereed)
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    Poster
  • 59.
    Andersson, Magnus
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Lantz, Jonas
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Turbulence Quantification of Stenotic Blood Flow Using Image-Based CFD: Effect of Different Interventions2014In: WCB 2014, 2014Conference paper (Other academic)
    Abstract [en]

    Turbulent blood flow is often associated with some sort of cardiovascular disease, e.g. sharp bends and/or sudden constrictions/expansions of the vessel wall. The energy losses associated with the turbulent flow may increase the heart workload in order to maintain cardiac output (CO). In the present study, the amount of turbulent kinetic energy (TKE) developed in the vicinity of an aortic coarctation was estimated pre-intervention and in a variety of post-intervention configurations, using scale-resolved image-based computational fluid dynamics (CFD). TKE can be measured using magnet resonance imaging (MRI) and have also been validated with CFD simulations [1], i.e. a parameter that not only can be quantified using simulations but can also be measured by MRI.

    Patient-specific geometry and inlet flow conditions were obtained using contrast-enhanced MR angiography and 2D cine phase-contrast MRI, respectively. The intervention procedure was mimicked using an inflation simulation, where six different geometries were obtained. A scale-resolving turbulence model, large eddy simulation (LES), was utilized to resolve the largest turbulent scales and also to capture the laminar-to-turbulent transition. All cases were simulated using baseline CO and with a 20% CO increase to simulate a possible flow adaption after intervention.

    For this patient, results shows a non-linear decay of the total amount of TKE integrated over the cardiac phase as the stenotic cross-sectional area is increased by the intervention.  Figure 1 shows the original segmented geometry and two dilated coarctation with corresponding volume rendering of the TKE at peak systole. Due to turbulent transition at a kink upstream the stenosis further dilation of the coarctation tends to restrict the TKE to a plateau, and continued vessel expansion may therefore only induce unnecessary stresses onto the arterial wall. 

    This patient-specific non-invasive framework has shown the geometrical impact on the TKE estimates. New insight in turbulence development indicates that the studied coarctation can only be improved to a certain extent, where focus should be on the upstream region, if further TKE reduction is motivated. The possibility of including MRI in a combined framework could have great potential for future intervention planning and follow-up studies.  

    [1] J. Lantz, T. Ebbers, J. Engvall and M. Karlsson, Numerical and Experimental Assessment of Turbulent Kinetic Energy in an Aortic Coarctation, Journal of Biomechnics, 2013. 46(11): p. 1851-1858.

  • 60.
    Andersson, Nils
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Marklund, Martin
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Adaptive Feature based Level of Detail for Memory Restrained Interactive Direct Volume Rendering2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this thesis was to find and implement an adaptive method, based on given data and hardware, for selecting different level-of-detail whilst preserving visual quality to the best extent possible. Another important aspect of the new method was that it had to be performance effective, since the target platform was an interactive direct volume rendering application. The project was targeted towards memory restricted systems in which it has previously been impossible to render large-scale volumetric datasets.

    The previous state of the target platform supports two detail levels: full and half, and does not implement any kind of prioritisation when selecting the level-of-detail of bricks. Apart from failing to render parts of the datasets, the old implementation is also lacking in that the top of the dataset always has the lowest prioritisation, which can prove problematic for certain datasets.

    An adaptive method which determines a suitable number of detail levels at run-time has been implemented. The new implementation has also reworked the way bricks are prioritised during rendering. The proposed algorithm prioritises bricks holding surface information as well as bricks that match the transfer-function configuration well.

    The results show that the proposed method is able to render large-scale datasets in limited environments whilst maintaining interactive frame-rates. The new brick selection algorithm is a step in the right direction towards solving the issue with parts of the dataset not being prioritised.

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  • 61.
    Andersson, Stina
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Hultstrand Klint, Andrea
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    A smart poster? Visual design of marketing material for an exhibition of the concept Smart City2015Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Företaget HiQ i Norrköping vill skapa en bättre värld genom att förenkla och förbättra människors liv med hjälp av teknik. Konceptet Smart City handlar om utmaningar inom områden som energi, miljö och trafik som Norrköping kommun kommer att ställas inför i framtiden. HiQ anordnar i maj 2015 ett hackathon där studenter under några timmar ska komma fram till olika Smart City-lösningar. Dessa idéer kommer sedan presenteras i en utställning på Visualiseringscenter i Norrköping. För att dra besökare till utställningen krävs det att utställningen marknadsförs mot en intresserad och relevant målgrupp. Marknadsföringen till utställningen ska verka för att övertyga målgruppen att gå på utställningen. En affisch togs därför fram efter teorier och utvärderades sedan under sex kvalitativa intervjuer. Därefter transkriberades de insamlade data och analyserades med hjälp av meningskoncentrering.Studien syftar till att undersöka hur en affisch bör utformas visuellt för att locka målgruppen, Medieteknikstudenter vid Linköpings universitet, till utställningen. För att locka målgruppen till utställningen bör affischen innehålla fler visuella element i form av bilder, det vill säga illustrationer eller fotografier som är kopplade till konceptet och utställningen. Den textbaserade informationen bör tydligare förklara vad det är utställningen handlar om. Affischen bör utformas mer utmärkande om den ska bli ihågkommen. För att affischen som utformades i denna studie ska generera det förväntade intrycket krävs en del justeringar.

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  • 62.
    Andersson, Thord
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Läthén, Gunnar
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Lenz, Reiner
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Borga, Magnus
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Modified Gradient Search for Level Set Based Image Segmentation2013In: IEEE Transactions on Image Processing, ISSN 1057-7149, E-ISSN 1941-0042, Vol. 22, no 2, p. 621-630Article in journal (Refereed)
    Abstract [en]

    Level set methods are a popular way to solve the image segmentation problem. The solution contour is found by solving an optimization problem where a cost functional is minimized. Gradient descent methods are often used to solve this optimization problem since they are very easy to implement and applicable to general nonconvex functionals. They are, however, sensitive to local minima and often display slow convergence. Traditionally, cost functionals have been modified to avoid these problems. In this paper, we instead propose using two modified gradient descent methods, one using a momentum term and one based on resilient propagation. These methods are commonly used in the machine learning community. In a series of 2-D/3-D-experiments using real and synthetic data with ground truth, the modifications are shown to reduce the sensitivity for local optima and to increase the convergence rate. The parameter sensitivity is also investigated. The proposed methods are very simple modifications of the basic method, and are directly compatible with any type of level set implementation. Downloadable reference code with examples is available online.

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  • 63.
    Andersson, Victor
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Björs, Matilda
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Internal communication of a brand - A comparative study within the municipality of Norrköping2014Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The municipality of Norrköping is a large organization with lots of different areas of expertise. To make sure that the values are the same throughout the organization is a heavy task but important if you want the brand to be communicated in the right way in all instances of the organization. An internal review of the employees opinions takes place every other year with the last one taking place in 2013. The results from the review made the municipality of Norrköping realise that they needed to increase their internal work with brand knowledge. The municipality of Norrköping took action and created a platform of communications called Let´s Create Norrköping. The problem they stand before now is that they're not sure if the employees have interpreted the information the correct way regarding the brand. This case study aims to investigate how the brand Norrköping is communicated throughout the plattform Let´s Create Norrköping and how the employees perceives the brand of the municipality of Norrköping.

    To answer the cause of the report a data collection has been made with interviews divided into two parts. The first part consists of an interview with Tina Vennerholm, brand developer at the communications department of the municipality of Norrköping. The main objective of this interviews was to conclude the main objectives of the platform Let´s Create Norrköping. The second part was conducted with five employees within the organization of the municipality of Norrköping. It was conducted to conclude their point of view of the platform Let´s Create Norrköping. Conclusions that can be drawn from the study include that the employees lack the presence of the representatives of the municipality of Norrköping at their working places. The employees have a positive opinion regarding the platform Let´s Create Norrköping although they have not received any internal information regarding the plattform. The reason to their positive opinions ought to be that they have been affected by external marketing regarding the plattform. This leads to the employees having a hard time with implementing the message of the platform in their work.

    Recommendations given to the municipality of Norrköping is to be visible at the various working places, to show the worker which people who are responsible for the communication at their workplace. to give the employees a personal connection to the source of the information that is given which makes it easier for the worker to accept and implement the information.

    The employees all have positive connections to the city of Norrköping. That is why the conductors of this study recommend that the municipality of Norrköping should make a connection to the city with the work that is made by the employees on all the different areas in the organization. This is to engage and motivate the employees and make them see and understand the connection between the city and the organization and the part that they play in it.

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  • 64.
    Andreopoulou, Areti
    et al.
    National and Kapodistrian University of Athens.
    Walker, Bruce N.Georgia Institute of Technology.McMullen, KylaUniversity of Florida.Rönnberg, NiklasLinköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Safe and Sound: Proceedings of the 27th Annual International Conference on Auditory Display2022Conference proceedings (editor) (Refereed)
  • 65.
    Angelakis, Vangelis
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Gundlegård, David
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Rajna, Botond
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Vrotsou, Katerina
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Carlsson, Richard
    Ericsson Research, Services & Software.
    Forgeat, Julien
    Ericsson Research, Services & Software.
    Hu, Tracy H
    Ericsson Research, Services & Software.
    Liu, Evan L
    Ericsson Research, Services & Software.
    Moritz, Simon
    Ericsson Research, Services & Software.
    Zhao, Sky
    Ericsson Research, Services & Software.
    Zheng, Yaotian
    Ericsson Research, Services & Software.
    Mobility modeling for transport efficiency: Analysis of travel characteristics based on mobile phone data2013In: Netmob 2013: Mobile phone data for development / [ed] Vincent Blondel, 2013Conference paper (Refereed)
    Abstract [en]

    Signaling data from the cellular networks can provide a means of analyzing the efficiency of a deployed transportation system and assisting in the formulation of transport models to predict its future use. An approach based on this type of data can be especially appealing for transportation systems that need massive expansions, since it has the added benefit that no specialized equipment or installations are required, hence it can be very cost efficient.

    Within this context in this paper we describe how such obtained data can be processed and used in order to act as enablers for traditional transportation analysis models. We outline a layered, modular architectural framework that encompasses the entire process and present results from initial analysis of mobile phone call data in the context of mobility, transport and transport infrastructure. We finally introduce the Mobility Analytics Platform, developed by Ericsson Research, tailored for mobility analysis, and discuss techniques for analyzing transport supply and demand, and give indication on how cell phone use data can be used directly to analyze the status and use of the current transport infrastructure.

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  • 66.
    Ankaräng, Nils
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Davidsson, Edvard
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Analys av arbetsplatsomkostnader2014Independent thesis Basic level (university diploma), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Konkurrensen inom byggbranschen har ökat de senaste åren och byggföretagen tvingas att ta större kontroll över sina kostnader för att fortsatt kunna driva en lönsam verksamhet. Intäkterna är något som man inte har så stora möjligheter att påverka, då det är bostadsmarknaden i stort som styr hur mycket man kan få betalt för sina produkter och byggnader. Den egna kostnadskontrollen och omkostnaderna har blivit det stora fokusområdet, då det är via dem som man kan förbättra sina marginaler. Detta arbete har skrivits i samarbete med JM Bostad Stockholm som idag har ett stort fokus inom detta område. Då projekten ofta är unika i sig kan det vara svårt att jämföra projekten med varandra för att se vilka arbetsplatser som är kostnadseffektiva samt i vilka skeden som ett byggprojekt är mest krävande gällande arbetsplatsomkostnader. Syftet med denna studie har varit att undersöka arbetsplatsomkostnader för byggnadsprojekt med liknande utformning. Detta för att få fram var i projekten arbetsplatsomkostnaderna uppstår och härleda dem till skeden i den strukturerade tidplanen och se hur de varierar efter den strukturerade tidplan som det arbetas efter. Detta för att efter avslutad studie kunna göra kostnadseffektiva projektplaneringar för ett mer konkurrenskraftigt byggande.

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  • 67.
    Antonsson, Andreas
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Kassander, Olivia
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Compelling interaction for large digital image archives2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Samhället idag sitter på ett stort kulturarv av bilder som nu digitaliserats i stora digitala bildarkiv. För att allmänheten ska få möjlighet att ta del av detta så har denna studie undersökt hur man kan skapa en interaktiv tjänst som ger åtkomst till ett stort antal bilder med en intresseväckande visuell upplevelse. För att besvara detta har en kvalitativ studie genomförts med en blandning av forskning genom design och fallstudie. Studiens har bestått av intervjuer med en intendent på Norrköpings stadsmuseum och fokusgrupper som besvarar målgruppens efterfrågan. Utifrån detta skapades designförslag som testades med hjälp av användbarhetstester och som därefter utvärderades genom en induktiv kvalitativ analys. Studiens resultat visar att skapandet av en interaktiv tjänst som ger åtkomst till ett stort antal bilder med en intresseväckande visuell upplevelse bör utgå från en tydlig och engagerande interaktion. Med bilder som får ta stor plats och med element som kan öka intresset i form av karta som visualliserar bildens position och tidslinje som ger möjlighet till filtrering.

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  • 68.
    Anzt, Hartwig
    et al.
    Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany; University of Tennessee, Knoxville, TN, USA.
    Bach, Felix
    Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
    Druskat, Stephan
    Friedrich Schiller University, Jena, Germany; German Aerospace Center (DLR), Berlin, Germany; Humboldt-Universität zu Berlin, Berlin, Germany.
    Löffler, Frank
    Friedrich Schiller University, Jena, Germany; Louisiana State University, Baton Rouge, LA, USA.
    Loewe, Axel
    Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
    Renard, Bernhard Y
    Hasso Plattner Institute, Digital Engineering Faculty, University of Potsdam, Potsdam, Germany.
    Seemann, Gunnar
    University Heart Centre Freiburg Bad Krozingen, Freiburg, Germany.
    Struck, Alexander
    Humboldt-Universität zu Berlin, Berlin, Germany.
    Achhammer, Elke
    Technische Universität München, München, Germany.
    Aggarwal, Piush
    Universität Duisburg-Essen, Duisburg, Germany.
    Appel, Franziska
    Leibniz Institute of Agricultural Development in Transition Economies (IAMO), Halle (Saale), Germany.
    Bader, Michael
    Technische Universität München, München, Germany.
    Brusch, Lutz
    Technische Universität Dresden, Dresden, Germany.
    Busse, Christian
    Deutsches Krebsforschungszentrum, Heidelberg, Germany.
    Chourdakis, Gerasimos
    Technische Universität München, München, Germany.
    Dabrowski, Piotr Wojciech
    Hochschule für Technik und Wirtschaft Berlin, Berlin, Germany.
    Ebert, Peter
    Saarland Informatics Campus, Saarbrücken, Germany.
    Flemisch, Bernd
    University of Stuttgart, Stuttgart, Germany.
    Friedl, Sven
    Berlin Institute of Health, Berlin, Germany.
    Fritzsch, Bernadette
    Alfred Wegener Institute, Bremerhaven, Germany.
    Funk, Maximilian D.
    Max-Planck-Gesellschaft e.V., München, Germany.
    Gast, Volker
    Friedrich Schiller University, Jena, Germany.
    Goth, Florian
    Universität Würzburg, Würzburg, Germany.
    Grad, Jean-Noël
    University of Stuttgart, Stuttgart, Germany.
    Hegewald, Jan
    Alfred Wegener Institute, Bremerhaven, Germany.
    Hermann, Sibylle
    University of Stuttgart, Stuttgart, Germany.
    Hohmann, Florian
    Universität Bremen, Bremen, Germany.
    Janosch, Stephan
    Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
    Kutra, Dominik
    European Molecular Biology Laboratory, Heidelberg, Germany.
    Linxweiler, Jan
    Technische Universität Braunschweig, Braunschweig, Germany.
    Muth, Thilo
    Federal Institute for Materials Research and Testing, Berlin, Germany.
    Peters-Kottig, Wolfgang
    Konrad-Zuse-Zentrum für Informationstechnik Berlin (ZIB), Berlin, Germany.
    Rack, Fabian
    FIZ Karlsruhe - Leibniz Institute for Information Infrastructure, Karlsruhe, Germany.
    Raters, Fabian H C
    University of Goettingen, Göttingen, Germany.
    Rave, Stephan
    University of Münster, Münster, Germany.
    Reina, Guido
    University of Stuttgart, Stuttgart, Germany.
    Reißig, Malte
    Institute for Advanced Sustainability Studies, Potsdam, Germany.
    Ropinski, Timo
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. Ulm University, Ulm, Germany.
    Schaarschmidt, Joerg
    Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
    Seibold, Heidi
    Ludwig Maximilian University of Munich, München, Germany.
    Thiele, Jan P
    Leibniz University Hannover, Hannover, Germany.
    Uekermann, Benjamin
    Eindhoven University of Technology, Eindhoven, The Netherlands.
    Unger, Stefan
    Julius Kühn-Institut (JKI), Quedlinburg, Germany.
    Weeber, Rudolf
    University of Stuttgart, Stuttgart, Germany.
    An environment for sustainable research software in Germany and beyond: current state, open challenges, and call for action2020In: F1000 Research, E-ISSN 2046-1402, Vol. 9Article in journal (Refereed)
    Abstract [en]

    Research software has become a central asset in academic research. It optimizes existing and enables new research methods, implements and embeds research knowledge, and constitutes an essential research product in itself. Research software must be sustainable in order to understand, replicate, reproduce, and build upon existing research or conduct new research effectively. In other words, software must be available, discoverable, usable, and adaptable to new needs, both now and in the future. Research software therefore requires an environment that supports sustainability. Hence, a change is needed in the way research software development and maintenance are currently motivated, incentivized, funded, structurally and infrastructurally supported, and legally treated. Failing to do so will threaten the quality and validity of research. In this paper, we identify challenges for research software sustainability in Germany and beyond, in terms of motivation, selection, research software engineering personnel, funding, infrastructure, and legal aspects. Besides researchers, we specifically address political and academic decision-makers to increase awareness of the importance and needs of sustainable research software practices. In particular, we recommend strategies and measures to create an environment for sustainable research software, with the ultimate goal to ensure that software-driven research is valid, reproducible and sustainable, and that software is recognized as a first class citizen in research. This paper is the outcome of two workshops run in Germany in 2019, at deRSE19 - the first International Conference of Research Software Engineers in Germany - and a dedicated DFG-supported follow-up workshop in Berlin.

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  • 69.
    Appelgren, Caroline
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Olsson, Lisa
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Ett branschperspektiv: normbrytning och stereotyper i reklam2014Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    På grund av stor konkurrens är det svårt att skapa reklam som fångar uppmärksamhet. Det finns olika verktyg för nå igenom mediaflödet. I den här studien undersöks orsaker och konsekvenser till användning av normbrytande- och stereotypisk kommunikation. Konsekvenser har tidigare studerats ur ett beteendevetarperspektiv. Studierna visar att reklam påverkar samhällets normer. Marknadskommunikativa orsaker tas inte upp och därför behövs en analys som lyfter fram för- och nackdelar ur reklambranschens perspektiv. Det förklarar varför stereotyper används och ger branschens intryck av konsekvenserna i att bryta eller förstärka normer. Den här studien har gjorts för att öka medvetenheten hos yrkesverksamma kommunikatörer. Datainsamling har gjorts genom kvalitativa intervjuer med sju yrkesverksamma kommunikatörer. Två reklamfilmer användes som diskussionsunderlag vid intervjuerna. Intervjuerna övergick sedan i mer allmänna frågor kring stereotyper, normer och normbrytande, informanterna fick reflektera över upplevda orsaker och konsekvenser. Slutsatser som kunnat dras från studien är att både normbrytning och stereotyper kan vara ett sätt att synas i dagens mediaflöde. Reklam är väldigt kundstyrt eftersom det är beställaren som tar störst risker med sitt varumärke och sin investering. Kommunikatörerna anser att deras största ansvar är gentemot beställaren. Stereotyper anses vara den säkra vägen. De identifieras snabbt och mycket slipper förklaras. I snabb kommunikation tar de inte onödig uppmärksamhet från budskapet. En nackdel med stereotyper är att de är opersonliga. De sticker inte ut ur mängden och reklamen glöms snabbt bort. En ytterligare nackdel med stereotyper anses vara att de påverkar samhället genom att förstärka fördomar och könsroller. Normbrytande reklam sticker ut och blir ihågkommen, vilket är en stor konkurrensfördel. Det kan också vara ett verktyg för ett långsiktigt identitetsskapande som skapar en målgruppsgemenskap och ett starkt varumärke. Normbrytning kan även påverka samhället genom att öka acceptans. En oro kring konsekvenserna av normbrytning leder till en försiktighet, både hos byråer och beställare. Risken är att få dålig publicitet och skada varumärket om det görs på del sätt. Det kan också göra kommunikationen otydlig och överskugga företagets produkt. Majoriteten av informanterna finner normbrytande reklam sällan förekommande. De upplever att de yngre generationerna har en större öppenhet och att normbrytning därför är vanligare i reklam riktad till ungdomar.

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  • 70.
    Arkstål, Axel
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Lidström, Kristofer
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Enkel vägvisning i en komplex miljö - Att hitta rätt på Linköpings Universitetssjukhus2014Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Att hitta rätt i den stora, komplexa miljön på Linköpings Universitetssjukhus är en utmaning. I nuläget finns skyltning och information i miljön men denna fungerar inte på ett tillräckligt bra sätt. Det är så pass bristande att man har guider vid entrén för att vägleda besökare rätt, något som är både opraktiskt och oekonomiskt. Syftet med denna designfallstudie var att utveckla ett wayshowingsystem för besökare på Linköpings Universitetssjukhus kring dess södra entré och i huvudbyggnaden. För att uppfylla syftet genomfördes ett antal kvalitativa intervjuer och observationer i miljön samt insamling av data från tidigare studier som gjorts i ämnet. Det slutliga resultatet är en kravlista för viktiga parametrar att ha i åtanke vid wayshowing på sjukhuset samt en skyltmanual baserad på kravlistan, med en detaljerad grund kring hur ett skyltsystem på sjukhuset ska se ut. Kravlistan ska kunna ligga till grund för all framtida skyltning på sjukhuset och samtliga krav är tänkta att alltid vara uppfyllda vid ny skyltning. Kraven innefattar framför allt att wayshowingen bör baseras på fysiska skyltar, det ska vara enkelt och tydligt att tolka samt att mängden information ska begränsas så mycket det går för att bli enklare att tyda. För att kunna implementera det nya skyltsystemet på hela sjukhuset behöver skyltmanualen kompletteras med detaljplanering för samtliga plan och byggnader, i nuläget är endast plan 9 och 10 i huvudbyggnaden färdiga för direkt implementation.

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  • 71.
    Arntén, Linnea
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    de Klerk, Paulina
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Att döma hunden efter håren: En designstudie i bokomslagets utformning och dess betydelse för högstadiekillars läslust2018Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    Statistik visar på att unga, framför allt killar, läser allt mindre. Detta kan antas bero på en rad olika faktorer, bland annat de senaste årens teknologiska framsteg. Denna studie ämnar undersöka hur ett omslag inom genren ungdomslitteratur kan utformas för att tilltala högstadiekillar samt hur stor betydelse omslaget har för målgruppens läslust. Utifrån insamlad data från målgruppen och yrkesverksamma inom bokbranschen samt relevanta teorier, har sex olika designförslag tagits fram. Designförslagen baserades på befintliga titlar från 2017. För att kunna uppfylla studiens syfte lät vi målgruppen och personer i närliggande grupper rent demografiskt värdera dessa, såväl som en formgivare på Bonnier Carlsen. Värderingen påvisade att målgruppen anser att det viktigaste med ett bokomslag är att det förmedlar en känsla. Avbildande illustrationer eller fotografier och tilltalande färger verkar spela en central roll för ett bokomslags attraktionskraft hos målgruppen. Typografi har visat sig vara mindre viktigt än motivet, medan helheten är det som verkar vara viktigast. Studien visar även att bokomslag har en stor betydelse för högstadiekillars läslust.

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    Att döma hunden efter håren: En designstudie i bokomslagets utformning och dess betydelse för högstadiekillars läslust
  • 72.
    Aronsson, Måns
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Karlsson Brefält, Simon
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Advanced Fieldline Rendering for Space Weather Visualization2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Sun is vital for life on Earth, but its life-giving powers can just as well be threatening. It is constantly bombarding the solar system with dangerous radiation and plasma, which Earth’s magnetic field is protecting us from. The Sun also possesses a strong magnetic field which interacts with Earth’s magnetic field in what is called the Dungey cycle. This master’s thesis project aims to find a method to visualize the Dungey cycle using moving magnetic fieldlines. This project is a continuation of a previously developed fieldline rendering project. The prior method uses a velocity vector field to trace a pathline around Earth, saving vertices at discrete steps; magnetic fieldlines are then traced from each vertex. These magnetic fieldlines are called key frames and are not visualized. They are instead used to interpolate the position of a rendered fieldline over time. The main issue with this prior method occurs when the Sun’s magnetic field links with Earth’s magnetosphere in what is called reconnection. Then, the topology of the fieldlines changes which makes them instantaneously jump to a new position. The developed method in this thesis is built upon the prior method, where both pathlines and key frames still are used. The concept of matching fieldlines is introduced to solve the issue with jumping fieldlines. It is implemented by using seed points close to critical points. Critical points are found externally and are used to trace fieldline pathlines to points where reconnection occurs, as reconnection always happens at critical points. The pathline to a critical point is created by tracing backward through the vector field. It then continues from the critical point by tracing it forward. A pair of matching fieldlines is created for each critical point; one fieldline represents the Sun’s magnetic field and the other represents Earth’s magnetic field. The starting positions of the fieldlines are adjusted to account for time differences to traverse their respective pathlines, to ensure that they meet at the critical point at approximately the same time. The two fieldlines interact and mix with each other as reconnection occurs, resulting in a smooth interpolation through the changing topology. This solves the issue with jumping fieldlines in the prior project and allows for smooth visualization of the Dungey cycle.

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  • 73.
    Arvidsson, Filip
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology.
    Bertilson, Jonas
    Linköping University, Department of Science and Technology, Media and Information Technology.
    Deep Learning for the prediction of RASER-MRI profiles2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Magnetic resonance imaging (MRI) is a critical diagnostic tool in medical practice, enabling non-invasive visualization of anatomy and physiological processes. Nonetheless, MRI has inherent spatial resolution limitations, which may limit its diagnostic capabilities. Recently, a new technology employing Radio-frequency Amplification by Stimulated emission of Radiation (RASER) has emerged to improve MRI resolution. Similar to a laser, RASER-MRI signals spontaneously emerge without the need for a radio frequency pulse(RF), which additionally enhances the safety of the process. However, RASER-MRI images frequently exhibit a significant presence of image artifacts due to the nonlinear behavior between image slices. This master’s thesis aims to determine whether image artifacts can be eliminated using deep artificial neural networks. The neural networks were trained on purely synthetic data, due to the complexity of real RASER experiments. The implementation was split into three phases. The first phase focused on the reconstruction of 1D RASER profiles. The test done during this phase showed that the reconstruction was preferably made with a Convolutional Neural Network (CNN). The CNN does not require knowledge of the total population inversion, and the ideal input was the most volatile RASER spectrum. The second phase was dedicated to reconstructing simulated RASER-MRI images. This phase started with the creation of a random RASER-MRI image generator which was used to generate the training and testing data. The reconstruction was successful and was further enhanced with an image-to-image Unet. The entire deep learning pipeline did not suffice for real data, which sparked the third phase. The third phase focused on simulating more realistic RASER data. The new data improved the result, however, the reconstruction did not suffice. Further research needs to be done into ways to make the simulation more realistic to improve the reconstruction of the real RASER-MRI image. However, this project concludes that simulated RASER-spectra can be reconstructed using deep learning.

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  • 74.
    Arvidsson, Filip
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Bertilson, Jonas
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Deep Learning for the prediction of Raser-MRI profiles2023Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    MRI is a critical diagnostic tool in medical practice, enabling non-invasive visualization of anatomy and physiological processes. Nonetheless, MRI has spatial resolution limitations, which may limit its diagnostic capabilities. Recently, a new technology employing Radio-frequency Amplification by Stimulated emission of Radiation (RASER) has emerged to improve MRI resolution. Similar to a laser, RASER-MRI signals spontaneously emerge without the need for a radiofrequency-pulse, which additionally enhances the safety ofthe process. However, RASER-MRI images frequently exhibit a significant presence of image artifacts due to the nonlinear behavior. Our work aims to determine whether the image artifacts can be eliminated using deep artificial neural networks. The proposed method involves training a deep artificial neural network on pure synthetic data. The data is generated by simulating RASER-signals from known image slices. Each image slice results in several RASER signals containing image artifacts which serve as input into our model. The model is supposed to reconstruct the image slice free of artifacts.

  • 75.
    Arvidsson, Linus
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Immersive Audio: Simulated Acoustics for Interactive Experiences2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A key aspect of immersive audio is realistic acoustics. To get plausible acoustics for an environment the impulse response can be generated using acoustic simulations and should ideally be updated in real-time for interactive applications. In this thesis the listening experience of sound generated with an interactive sound propagation engine was explored and compared to spatial sound produced with a static impulse response. The aim was to evaluate the sound experience for applications outside of virtual reality, with computational cost in consideration. This was done by conducting a user study where the participants got to interact and compare the two sound methods in different environments. The study was performed using a custom developed application integrated with a pre-existing sound propagation engine. The results from the user study showed no obvious perceptive difference between the two sound rendering methods that could justify the extra computations. Overall there was even a slight preference for the stereo method that used a static impulse response. However, there were qualities to both sound rendering methods that were preferred depending on the environment. Another thing that was investigated in the work of this thesis was how the varying accuracy of localization of sound in different directions can be used in acoustic ray tracing algorithms. An alternative sampling method was developed that uses a biased distribution based on spatial resolution of human hearing instead of traditional uniform sampling. The computation time of the random sampling phase increases, but could potentially reduce the number of ray samples needed.

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  • 76.
    Arvola, Mattias
    et al.
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, Faculty of Arts and Sciences.
    Bardzell, Jeffrey
    Indiana University, USA.
    Holmlid, Stefan
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, Faculty of Science & Engineering.
    Löwgren, Jonas
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    What we mean by interactive form2018In: interactions, ISSN 1072-5520, E-ISSN 1558-3449, Vol. 25, no 4, p. 6-7Article in journal (Other (popular science, discussion, etc.))
    Abstract [en]

    The following blog post is edited from an email conversation between the authors about the concept of interactive form, which incidentally is the name of a course given at Linköping University. If you do teach a course, it might be a good idea to understand the meaning of the course name.

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  • 77.
    Arvola, Mattias
    et al.
    Linköping University, Department of Computer and Information Science, MDALAB - Human Computer Interfaces. Linköping University, The Institute of Technology.
    Lundberg, Jonas
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Holmlid, Stefan
    Linköping University, Department of Computer and Information Science, MDALAB - Human Computer Interfaces. Linköping University, The Institute of Technology.
    Analysis of precedent designs: Competitive analysis meets genre analysis2010In: NordiCHI '10 Proceedings of the 6th Nordic Conference on Human-Computer Interaction: Extending Boundaries / [ed] Hvannberg, E. Þ., Lárusdóttir, M. K., Blandford, A., Gulliksen, J., New York, NY, USA: Association for Computing Machinery (ACM), 2010, p. 23-31Conference paper (Refereed)
    Abstract [en]

    Designers need to survey the competition and analyze precedent designs, but methods for that purpose have not been evaluated in earlier research. This paper makes a comparative evaluation between competitive analysis and genre analysis. A randomized between-group experiment was conducted where graphic design students were conducted one of the two analysis methods. There were 13 students in one group and 16 in the other. The results show that genre analysis produced more detailed descriptions of precedent designs, but its process was more difficult to understand. It is concluded that genre analysis can be integrated into competitive analysis, to make use of the strengths of both methods in the analysis of precedents.

  • 78.
    Arzani, Amirhossein
    et al.
    IIT.
    Dyverfeldt, Petter
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Ebbers, Tino
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Shadden, Shawn C
    IIT.
    In Vivo Validation of Numerical Prediction for Turbulence Intensity in an Aortic Coarctation2012In: Annals of Biomedical Engineering, ISSN 0090-6964, E-ISSN 1573-9686, Vol. 40, no 4, p. 860-870Article in journal (Refereed)
    Abstract [en]

    This paper compares numerical predictions of turbulence intensity with in vivo measurement. Magnetic resonance imaging (MRI) was carried out on a 60-year-old female with a restenosed aortic coarctation. Time-resolved three-directional phase-contrast (PC) MRI data was acquired to enable turbulence intensity estimation. A contrast-enhanced MR angiography (MRA) and a time-resolved 2D PCMRI measurement were also performed to acquire data needed to perform subsequent image-based computational fluid dynamics (CFD) modeling. A 3D model of the aortic coarctation and surrounding vasculature was constructed from the MRA data, and physiologic boundary conditions were modeled to match 2D PCMRI and pressure pulse measurements. Blood flow velocity data was subsequently obtained by numerical simulation. Turbulent kinetic energy (TKE) was computed from the resulting CFD data. Results indicate relative agreement (error a parts per thousand 10%) between the in vivo measurements and the CFD predictions of TKE. The discrepancies in modeled vs. measured TKE values were within expectations due to modeling and measurement errors.

  • 79.
    Asa, Sylvia
    et al.
    Department of Pathology, University Health Network, Toronto, Ontario, Canada.
    Bodén, Anna
    Linköping University, Department of Clinical and Experimental Medicine, Divison of Neurobiology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Clinical pathology.
    Treanor, Darren
    University of Leeds, and Leeds Teaching Hospitals NHS Trust Leeds, UK.
    Jarkman, Sofia
    Linköping University, Department of Clinical and Experimental Medicine, Divison of Neurobiology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Clinical pathology.
    Lundström, Claes
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Pantatnowitz, Liron
    Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, USA.
    2020 vision of digital pathology in action2019In: Journal of Pathology Informatics, ISSN 2229-5089, E-ISSN 2153-3539, Vol. 10, no 27Article in journal (Other academic)
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  • 80.
    Attaullah, Muhammad
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    An LTE implementation based on a road traffic density model2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The increase in vehicular traffic has created new challenges in determining the behavior of performance of data and safety measures in traffic. Hence, traffic signals on intersection used as cost effective and time saving tools for traffic management in urban areas. But on the other hand the signalized intersections in congested urban areas are the key source of high traffic density and slow traffic. High traffic density causes the slow network traffic data rate between vehicle to vehicle and vehicle to infrastructure. To match up with the emerging technologies, LTE takes the lead with good packet delivery and versatile to changes in the network due to vehicular movements and density.

    This thesis is about analyzing of LTE implementation based on a road traffic density model. This thesis work is aimed to use probability distribution function to calculate density values and develop a real traffic scenario in LTE network using density values.

    In order to analyze the traffic behavior, Aimsun simulator software has been used to represent the real situation of traffic density on a model intersection. For a realistic traffic density model field measurement were used for collection of input data. After calibration and validation process, a close to realty results extracted and used a logistic curve of probability distribution function to find out the density situation on each part of intersection. Similar traffic scenarios were implemented on MATLAB based LTE system level simulator.

    Results were concluded with the whole traffic scenario of 90 seconds and calculating the throughput at every traffic signal time and section.

    It is quite evident from the results that LTE system adopts the change of traffic behavior with dynamic nature and allocates more bandwidth where it is more needed.

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  • 81.
    Atterflod, Melina
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Glenning Ströberg, Frida
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Olivolja, fetaost och profilering – en fallstudie om att förmedla ett varumärkes kärnvärden genom storytelling2019Independent thesis Basic level (university diploma), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    Kandidatarbetet syftar till att genom en designansats undersöka hur ett företag kan förmedla varumärkets kärnvärden genom storytelling. Detta görs genom en reklamfilm, med företaget Zeta som exempelvarumärke.

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    Olivolja, fetaost och profilering – en fallstudie om att förmedla ett varumärkes kärnvärden genom storytelling
  • 82.
    Axelsson, Emil
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Costa, Jonathas
    NYU, NY 10003 USA.
    Silva, Claudio
    NYU, NY 10003 USA.
    Emmart, Carter
    Amer Museum Nat Hist, NY 10024 USA.
    Bock, Alexander
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Dynamic Scene Graph: Enabling Scaling, Positioning, and Navigation in the Universe2017In: Computer graphics forum (Print), ISSN 0167-7055, E-ISSN 1467-8659, Vol. 36, no 3, p. 459-468Article in journal (Refereed)
    Abstract [en]

    In this work, we address the challenge of seamlessly visualizing astronomical data exhibiting huge scale differences in distance, size, and resolution. One of the difficulties is accurate, fast, and dynamic positioning and navigation to enable scaling over orders of magnitude, far beyond the precision of floating point arithmetic. To this end we propose a method that utilizes a dynamically assigned frame of reference to provide the highest possible numerical precision for all salient objects in a scene graph. This makes it possible to smoothly navigate and interactively render, for example, surface structures on Mars and the Milky Way simultaneously. Our work is based on an analysis of tracking and quantification of the propagation of precision errors through the computer graphics pipeline using interval arithmetic. Furthermore, we identify sources of precision degradation, leading to incorrect object positions in screen-space and z-fighting. Our proposed method operates without near and far planes while maintaining high depth precision through the use of floating point depth buffers. By providing interoperability with order-independent transparency algorithms, direct volume rendering, and stereoscopy, our approach is well suited for scientific visualization. We provide the mathematical background, a thorough description of the method, and a reference implementation.

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  • 83.
    Axelsson, Emil
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Forsyth Rosin, Tomas
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Spatial-temporal multi-modal visualization of volumetric simulation and in situ satellite data2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis describes the work done by two students from Link¨oping University during a five month stay at Community Coordinated Modelling Center (CCMC) at the National Aeronautics and Space Administration (NASA). The work includes the implementation of algorithms for rendering time-varying volume simulation data from space weather simulations hosted by the CCMC, as well as visualizing photo sequences taken by the Solar Dynamics Observatory (SDO) satellite orbiting Earth. Both these capabilities are added to the OpenSpace software to create a multi-modal visualization where scientists, as well as museum audiences, can observe the Sun’s activity and its effects on the heliosphere as a whole.

    Both the simulation data and the image sequence provided by the SDO are typically larger than what can be fitted into the main memory of modern computers, which requires the data to be streamed from disk. Due to limitations caused by disk and GPU bandwidth, it is not possible to stream the full resolution data sets in interactive frame rates.

    A multi-resolution bricking scheme is implemented to allow for interactive visualization of the large volumetric data sets. To decrease GPU memory usage and minimize data streaming, subvolumes are represented using different spatial and temporal resolution depending on their relative importance to the visual quality. By introducing the concept of a memory budget and a streaming budget, the algorithm allows the user to control how the limited memory and streaming resources are utilized.

    To decrease the amount of data to be streamed when visualizing image sequences from SDO, a simpler multi-resolution bricking scheme has been implemented. Spatial resolution of different subregions of the image is varied based on their visibility and projected size on the screen. Results show that the presented implementations enable interactive visualization of volumetric space weather data and satellite data. By varying the streaming budget and memory budget for a volumetric simulation, frame rate can be traded against visual quality.

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    Spatial-temporal multi-modal visualization of volumetric simulation and in situ satellite data
  • 84.
    Axelsson, Maria
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Gamla material presenterade i nya medier2018Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [sv]

    Sedan mitten av 90-talet när internet fick sin framfart har konsumtionssamhället exploderat. Vem som helst har tillgång till vad som helst, och genom webbshopar kan också vem som helst starta sin egen digitala butik. En person vill ge sig in på webbhandelsmarknaden genom att börja sälja inredningsprodukter som skulpturer, lampor och tavlor, egentillverkade i naturmaterial. Detta ska göras i en webbshop vid namn Timmar. Föreliggande studie undersöker hur denna webbshop kan formges på bästa sätt för att framhäva produkterna och tilltala målgruppen, som består av inredningsintresserade personer mellan 25 och 50 år. Som grund ligger tidigare forskning, en förstudie och underlag från Timmar. Med hjälp av detta har det genom brainstorming tagits fram olika designkoncept med tillhörande idéer. Dessa har sållats ner till slutligen två designkoncept med hjälp av tankekartor och en värderingsmatris. De två slutliga designkonceptens kallas modernt och naturligt och formgivningsmässigt innehåller dessa varsin logotyp, bilder, färger, teckensnitt samt återkommande element. Koncepten har analyserats utifrån en enkätundersökning och intervjuer med företagets målgrupp samt en intervju med en webbdesigner. Värderingen landade i att konceptet naturligt rekommenderas, dock med vissa modifikationer för att behålla en modern känsla.

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    Old materials presented in new medias
  • 85.
    Axelsson, Sofie
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Hollén, Karolina
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Influencer marketing: Hur det påverkar unga kvinnor i generation Z2020Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    As advertising fatigue increases in the western world, influencer marketing is growing ever stronger as a marketing strategy. Influencers, who are basically ordinary people, earn great power on their social media platforms with thousands to millions of followers. They partner with companies for money and free products, and in return, they help companies by reaching huge target groups. In addition to paid partnerships, they publish beautiful images that strengthen their brand, which usually means to emphasize themselves as good looking, funny and nice people with fantastic and desirable lives.

    The fact that influencer marketing is an effective form of marketing has probably been gaining ground, but in addition to influencing consumers' purchasing behavior, they also have some influence on them on a deeper level. Given previous research examining a slightly older female target group young women in generation Z were selected as the target group for this study. The target group hass grown up with social media and is therefore interesting to investigate. Thus, the purpose of the study is to investigate how women in generation Z are influenced by influencer marketing on Instagram. To answer the purpose, two questions at issue were formulated, and the study was conducted using a qualitative method that consisted of interviews with a sample group of young women aged 15-20 and with the help of image analyzes of an influencer's Instagram feed.

    The results of the study showed that influencers affect young women in generation Z by painting up inventive problems, which they reinforce with unattainable, perfect ideal images while creating strong relationships with their followers. This means that the audience, despite being critical of influencers and aware that everything is not as perfect as it seems on Instagram, compares themselves - their looks and their lives - and thus questions their identity and consumes in hopes of strengthening it and to solve the painted problems as well as trying to achieve the ideal image. This contributes to stress and pressure, and in some cases mental illness. Belonging to a group is important for the target group when creating their identity and they feel that Instagram contributes to a fear of exclusion, while cultivating influencers and staying up to date on social media helps them feel group affiliation. However, they are generally positive to influencers in the aspect that they contribute to entertainment and inspiration. They find themselves seeing a positive trend among some influencers that everything no longer has to be perfect, which makes them feel like they are able to trust them more.

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  • 86.
    Axelsson, Viktor
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Automatisk segmentering och maskering av implantat i mammografibilder2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A report on my thesis developing an algorithm to automatically classify a mammogram image as containing an implant or not and segmenting and masking any present breast implant in the image.

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  • 87.
    Axelsson, Wilma
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Engström, Nellie
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Large-scale Exploratory Text Visualisation2023Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The amount of available text data has increased rapidly in the latest years, making it difficult for an everyday user to find relevant information. To solve this, NLP and visualisation methods have been developed for extracting valuable information from text and presenting it to the user. The aim of this project is to implement a proof-of-concept visualisation prototype for exploring a large amount of Swedish news articles with related metadata and investigate the temporal and relational aspects of the data. The project was divided into three major parts. In the first part, sketches of the visualisation were designed and evaluated through user tests. The second part consisted of designing and implementing a NLP pipeline, using BERTopic, where both Dynamic Topic Modeling (DTM) and Hierarchical Topic Modeling (HTM) were used. Some parameters of the pipeline were evaluated using evaluation metrics and through visual inspection, for instance a Swedish sentence transformer. The final part consisted of implementing and evaluating the visualisation prototype. The project resulted in a web-based visualisation, presenting the NLP results, with two different views: a top 10 topics view and a hierarchical view containing all topics. The prototype has various features, e.g., clicking and hovering for details-on-demand and options for changing and altering the view. The prototype was then evaluated through an internal case study and user tests. For the user tests, there were two groups of participants: people working in the journalism field and people working closely to the NLP field. Both groups thought there was more value in viewing the top 10 topics view than the hierarchical view. Furthermore, the quality of the top 10 topics view was considered higher overall compared to the hierarchical view. In the end, the result of this project is a proof-of-concept visualisation prototype presenting topics of Swedish news articles, over time and in relation to each other. A few possible improvement possibilities include improving the hierarchical relations between the topics and the run time of the topic model and prototype. Also, the prototype may be further improved with additional features, e.g., real-time data, a map, the full text of the articles and a search function.

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  • 88. Order onlineBuy this publication >>
    Axholt, Magnus
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Pinhole Camera Calibration in the Presence of Human Noise2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The research work presented in this thesis is concerned with the analysis of the human body as a calibration platform for estimation of a pinhole camera model used in Augmented Reality environments mediated through Optical See-Through Head-Mounted Display. Since the quality of the calibration ultimately depends on a subject’s ability to construct visual alignments, the research effort is initially centered around user studies investigating human-induced noise, such as postural sway and head aiming precision. Knowledge about subject behavior is then applied to a sensitivity analysis in which simulations are used to determine the impact of user noise on camera parameter estimation.

    Quantitative evaluation of the calibration procedure is challenging since the current state of the technology does not permit access to the user’s view and measurements in the image plane as seen by the user. In an attempt to circumvent this problem, researchers have previously placed a camera in the eye socket of a mannequin, and performed both calibration and evaluation using the auxiliary signal from the camera. However, such a method does not reflect the impact of human noise during the calibration stage, and the calibration is not transferable to a human as the eyepoint of the mannequin and the intended user may not coincide. The experiments performed in this thesis use human subjects for all stages of calibration and evaluation. Moreover, some of the measurable camera parameters are verified with an external reference, addressing not only calibration precision, but also accuracy.

    List of papers
    1. User Boresighting for AR Calibration: A Preliminary Analysis
    Open this publication in new window or tab >>User Boresighting for AR Calibration: A Preliminary Analysis
    2008 (English)In: Proceedings of the IEEE Virtual Reality Conference 2008, IEEE , 2008, p. 43-46Conference paper, Published paper (Refereed)
    Abstract [en]

    The precision with which users can maintain boresight alignment between visual targets at different depths is recorded for 24 subjects using two different boresight targets. Subjects' normal head stability is established using their Romberg coefficients. Weibull distributions are used to describe the probabilities of the magnitude of head positional errors and the three dimensional cloud of errors is displayed by orthogonal two dimensional density plots. These data will lead to an understanding of the limits of user introduced calibration error in augmented reality systems.

    Place, publisher, year, edition, pages
    IEEE, 2008
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-72053 (URN)10.1109/VR.2008.4480748 (DOI)978-1-4244-1971-5 (ISBN)
    Conference
    IEEE Virtual Reality Conference, 2008. VR '08, 8-12 March, Reno, Nevada, USA
    Available from: 2011-11-14 Created: 2011-11-14 Last updated: 2011-11-21Bibliographically approved
    2. User Boresight Calibration Precision for Large-Format Head-Up Displays
    Open this publication in new window or tab >>User Boresight Calibration Precision for Large-Format Head-Up Displays
    2008 (English)In: Proceedings of the 2008 ACM symposium on Virtual reality software and technology, New York, NY, USA: ACM , 2008, p. 141-148Conference paper, Published paper (Refereed)
    Abstract [en]

    The postural sway in 24 subjects performing a boresight calibration task on a large format head-up display is studied to estimate the impact of human limits on boresight calibration precision and ultimately on static registration errors. The dependent variables, accumulated sway path and omni-directional standard deviation, are analyzed for the calibration exercise and compared against control cases where subjects are quietly standing with eyes open and eyes closed. Findings show that postural stability significantly deteriorates during boresight calibration compared to when the subject is not occupied with a visual task. Analysis over time shows that the calibration error can be reduced by 39% if calibration measurements are recorded in a three second interval at approximately 15 seconds into the calibration session as opposed to an initial reading. Furthermore parameter optimization on experiment data suggests a Weibull distribution as a possible error description and estimation for omni-directional calibration precision. This paper extends previously published preliminary analyses and the conclusions are verified with experiment data that has been corrected for subject inverted pendulum compensatory head rotation by providing a better estimate of the position of the eye. With correction the statistical findings are reinforced.

    Place, publisher, year, edition, pages
    New York, NY, USA: ACM, 2008
    Keywords
    boresight, line of sight, calibration, postural sway, augmented reality
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-43489 (URN)10.1145/1450579.1450610 (DOI)73950 (Local ID)978-1-59593-951-7 (ISBN)73950 (Archive number)73950 (OAI)
    Conference
    15th ACM Symposium on Virtual Reality Software and Technology, Bordeaux, France October 27-29
    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2011-11-14Bibliographically approved
    3. Visual Alignment Precision in Optical See - Through AR Displays: Implications for Potential Accuracy
    Open this publication in new window or tab >>Visual Alignment Precision in Optical See - Through AR Displays: Implications for Potential Accuracy
    2009 (English)In: Proceedings of the ACM/IEEE Virtual Reality International Conference, Association for Computing Machinery (ACM), 2009Conference paper, Published paper (Other academic)
    Abstract [en]

    The quality of visual registration achievable with anoptical see-through head mounted display (HMD)ultimately depends on the user’s targetingprecision. This paper presents design guidelines forcalibration procedures based on measurements ofusers’ head stability during visual alignment withreference targets. Targeting data was collected from12 standing subjects who aligned a head fixedcursor presented in a see-through HMD withbackground targets that varied in azimuth (0°, ±30°,±60°) and elevation (0°, ±10°). Their data showedthat: 1) Both position and orientation data will needto be used to establish calibrations based on nearbyreference targets since eliminating body swayeffects can improve calibration precision by a factorof 16 and eliminate apparent angular anisotropies.2) Compensation for body sway can speed thecalibration by removing the need to wait for thebody sway to abate, and 3) calibration precision canbe less than 2 arcmin even for head directionsrotated up to 60° with respect to the user’s torsoprovided body sway is corrected. Users ofAugmented Reality (AR) applications overlookinglarge distances may avoid the need to correct forbody sway by boresighting on markers at relativelylong distances, >> 10 m. These recommendationscontrast with those for heads up displays using realimages as discussed in previous papers.

    Place, publisher, year, edition, pages
    Association for Computing Machinery (ACM), 2009
    National Category
    Computer Engineering
    Identifiers
    urn:nbn:se:liu:diva-52848 (URN)
    Conference
    ACM/IEEE Virtual Reality International Conference, 2009
    Available from: 2010-01-12 Created: 2010-01-12 Last updated: 2018-01-12Bibliographically approved
    4. Visual Alignment Accuracy in Head Mounted Optical See-Through AR Displays: Distribution of Head Orientation Noise
    Open this publication in new window or tab >>Visual Alignment Accuracy in Head Mounted Optical See-Through AR Displays: Distribution of Head Orientation Noise
    2009 (English)In: Proceedings of the Human Factors and Ergonomics Society 53rd Annual Meeting 2009, San Antonio (TX), USA: Human Factors and Ergonomics Society , 2009, p. 2024-2028Conference paper, Published paper (Refereed)
    Abstract [en]

    The mitigation of registration errors is a central challenge for improving the usability of AugmentedReality systems. While the technical achievements within tracking and display technology continue toimprove the conditions for good registration, little research is directed towards understanding theuser’s visual alignment performance during the calibration process. This paper reports 12 standingsubjects’ visual alignment performance using an optical see-through head mounted display for viewingdirections varied in azimuth (0°, ±30°, ±60°) and elevation (0°, ±10°). Although viewing direction hasa statistically significant effect on the shape of the distribution, the effect is small and negligible forpractical purposes and can be approximated to a circular distribution with a standard deviation of 0.2°for all viewing directions studied in this paper. In addition to quantifying head aiming accuracy with ahead fixed cursor and illustrating the deteriorating accuracy of boresight calibration with increasingviewing direction extremity, the results are applicable for filter design determining the onset and end ofhead rotation.

    Place, publisher, year, edition, pages
    San Antonio (TX), USA: Human Factors and Ergonomics Society, 2009
    National Category
    Computer Engineering
    Identifiers
    urn:nbn:se:liu:diva-52854 (URN)10.1177/154193120905302710 (DOI)978-161567623-1 (ISBN)
    Conference
    53rd Human Factors and Ergonomics Society Annual Meeting 2009, HFES 2009; San Antonio, TX; United States
    Available from: 2010-01-12 Created: 2010-01-12 Last updated: 2018-01-12Bibliographically approved
    5. Optical See-Through Head Mounted Display: Direct Linear Transformation Calibration Robustness in the Presence of User Alignment Noise
    Open this publication in new window or tab >>Optical See-Through Head Mounted Display: Direct Linear Transformation Calibration Robustness in the Presence of User Alignment Noise
    Show others...
    2010 (English)In: Proceedings of the 54th Annual Meeting of the Human Factors and Ergonomics Society, 2010Conference paper, Published paper (Refereed)
    Abstract [en]

    The correct spatial registration between virtual and real objects in optical see-through augmented reality implies accurate estimates of the user’s eyepoint relative to the location and orientation of the display surface. A common approach is to estimate the display parameters through a calibration procedure involving a subjective alignment exercise. Human postural sway and targeting precision contribute to imprecise alignments, which in turn adversely affect the display parameter estimation resulting in registration errors between virtual and real objects. The technique commonly used has its origin incomputer vision, and calibrates stationary cameras using hundreds of correspondence points collected instantaneously in one video frame where precision is limited only by pixel quantization and image blur. Subsequently the input noise level is several order of magnitudes greater when a human operator manually collects correspondence points one by one. This paper investigates the effect of human alignment noise on view parameter estimation in an optical see-through head mounted display to determine how well astandard camera calibration method performs at greater noise levels than documented in computer vision literature. Through Monte-Carlo simulations we show that it is particularly difficult to estimate the user’s eyepoint in depth, but that a greater distribution of correspondence points in depth help mitigate the effects of human alignment noise.

    Keywords
    Head-mounted display, Calibration, Direct linear transform, Robustness
    National Category
    Control Engineering
    Identifiers
    urn:nbn:se:liu:diva-60435 (URN)9780945289371 (ISBN)
    Conference
    54th Annual Meeting of the Human Factors and Ergonomics Society, San Francisco, USA, 27 September-1 October, 2010
    Available from: 2010-10-13 Created: 2010-10-13 Last updated: 2015-09-22Bibliographically approved
    6. Parameter Estimation Variance of the Single Point Active Alignment Method in Optical See-Through Head Mounted Display Calibration
    Open this publication in new window or tab >>Parameter Estimation Variance of the Single Point Active Alignment Method in Optical See-Through Head Mounted Display Calibration
    Show others...
    2011 (English)In: Proceedings of the IEEE Virtual Reality Conference / [ed] Michitaka Hirose, Benjamin Lok, Aditi Majumder and Dieter Schmalstieg, Piscataway, NJ, USA: IEEE , 2011, p. 27-24Conference paper, Published paper (Refereed)
    Abstract [en]

    The parameter estimation variance of the Single Point Active Alignment Method (SPAAM) is studied through an experiment where 11 subjects are instructed to create alignments using an Optical See-Through Head Mounted Display (OSTHMD) such that three separate correspondence point distributions are acquired. Modeling the OSTHMD and the subject's dominant eye as a pinhole camera, findings show that a correspondence point distribution well distributed along the user's line of sight yields less variant parameter estimates. The estimated eye point location is studied in particular detail. Thefindings of the experiment are complemented with simulated datawhich show that image plane orientation is sensitive to the numberof correspondence points. The simulated data also illustrates someinteresting properties on the numerical stability of the calibrationproblem as a function of alignment noise, number of correspondencepoints, and correspondence point distribution.

    Place, publisher, year, edition, pages
    Piscataway, NJ, USA: IEEE, 2011
    Series
    IEEE Virtual Reality Conference, ISSN 1087-8270
    Keywords
    single point active alignment method, camera resectioning, calibration, optical see-through head mounted display, augmented reality
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-67233 (URN)10.1109/VR.2011.5759432 (DOI)000297260400004 ()978-1-4577-0037-8 (online), 978-1-4577-0039-2 (print) (ISBN)
    Conference
    IEEE Virtual Reality Conference, pages 27–34, Singapore, Republic of Singapore
    Available from: 2011-04-04 Created: 2011-04-04 Last updated: 2015-09-22Bibliographically approved
    7. Accuracy of Eyepoint Estimation in Optical See-Through Head-Mounted Displays Using the Single Point Active Alignment Method
    Open this publication in new window or tab >>Accuracy of Eyepoint Estimation in Optical See-Through Head-Mounted Displays Using the Single Point Active Alignment Method
    Show others...
    2011 (English)Conference paper, Published paper (Other academic)
    Abstract [en]

    This paper studies the accuracy of the estimated eyepoint of an Optical See-Through Head-Mounted Display (OST HMD) calibrated using the Single Point Active Alignment Method (SPAAM). Quantitative evaluation of calibration procedures for OST HMDs is complicated as it is currently not possible to share the subject’s view. Temporarily replacing the subject’s eye with a camera during the calibration or evaluation stage has been proposed, but the uncertainty of a correct eyepoint estimation remains. In the experiment reported in this paper, subjects were used for all stages of calibration and the results were verified with a 3D measurement device. The nine participants constructed 25 visual alignments per calibration after which the estimated pinhole camera model was decomposed into its intrinsic and extrinsic parameters using two common methods. Unique to this experiment, compared to previous evaluations, is the measurement device used to cup the subject’s eyeball. It measures the eyepoint location relative to the head tracker, thereby establishing the calibration accuracy of the estimated eyepoint location. As the results on accuracy are expressed as individual pinhole camera parameters, rather than a compounded registration error, this paper complements  previously published work on parameter variance as the former denotes bias and the latter represents noise. Results indicate that the calibrated eyepoint is on average 5 cm away from its measured location and exhibits a vertical bias which potentially causes dipvergence for stereoscopic vision for objects located further away than 5.6 m. Lastly, this paper closes with a discussion on the suitability of the traditional pinhole camera model for OST HMD calibration.

    Keywords
    Accuracy, Single Point Active Alignment Method, Visual Alignment, Calibration, Augmented Reality
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-72054 (URN)
    Conference
    IEEE Virtual Reality Conference 2012, Orange County (CA), USA
    Available from: 2011-11-14 Created: 2011-11-14 Last updated: 2015-09-22Bibliographically approved
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    Pinhole Camera Calibration in the Presence of Human Noise
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  • 89.
    Axholt, Magnus
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Peterson, Stephen
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Ellis, Stephen R.
    Human Systems Integration Division, NASA Ames Research Center.
    User Boresighting for AR Calibration: A Preliminary Analysis2008In: Proceedings of the IEEE Virtual Reality Conference 2008, IEEE , 2008, p. 43-46Conference paper (Refereed)
    Abstract [en]

    The precision with which users can maintain boresight alignment between visual targets at different depths is recorded for 24 subjects using two different boresight targets. Subjects' normal head stability is established using their Romberg coefficients. Weibull distributions are used to describe the probabilities of the magnitude of head positional errors and the three dimensional cloud of errors is displayed by orthogonal two dimensional density plots. These data will lead to an understanding of the limits of user introduced calibration error in augmented reality systems.

  • 90.
    Axholt, Magnus
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Skoglund, Martin A.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    O’Connell, Stephen D.
    Swedish Air Force Combat Simulation Center at the Swedish Defence Research Agency.
    Cooper, Matthew D.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Ellis, Stephen R.
    Human Systems Integration Division at NASA Ames Research Center.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Accuracy of Eyepoint Estimation in Optical See-Through Head-Mounted Displays Using the Single Point Active Alignment Method2011Conference paper (Other academic)
    Abstract [en]

    This paper studies the accuracy of the estimated eyepoint of an Optical See-Through Head-Mounted Display (OST HMD) calibrated using the Single Point Active Alignment Method (SPAAM). Quantitative evaluation of calibration procedures for OST HMDs is complicated as it is currently not possible to share the subject’s view. Temporarily replacing the subject’s eye with a camera during the calibration or evaluation stage has been proposed, but the uncertainty of a correct eyepoint estimation remains. In the experiment reported in this paper, subjects were used for all stages of calibration and the results were verified with a 3D measurement device. The nine participants constructed 25 visual alignments per calibration after which the estimated pinhole camera model was decomposed into its intrinsic and extrinsic parameters using two common methods. Unique to this experiment, compared to previous evaluations, is the measurement device used to cup the subject’s eyeball. It measures the eyepoint location relative to the head tracker, thereby establishing the calibration accuracy of the estimated eyepoint location. As the results on accuracy are expressed as individual pinhole camera parameters, rather than a compounded registration error, this paper complements  previously published work on parameter variance as the former denotes bias and the latter represents noise. Results indicate that the calibrated eyepoint is on average 5 cm away from its measured location and exhibits a vertical bias which potentially causes dipvergence for stereoscopic vision for objects located further away than 5.6 m. Lastly, this paper closes with a discussion on the suitability of the traditional pinhole camera model for OST HMD calibration.

  • 91.
    Axholt, Magnus
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Skoglund, Martin
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    O'Connell, Stephen
    Swedish Defence Research Agency.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Ellis, Stephen
    NASA Ames Research Center.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Parameter Estimation Variance of the Single Point Active Alignment Method in Optical See-Through Head Mounted Display Calibration2011In: Proceedings of the IEEE Virtual Reality Conference / [ed] Michitaka Hirose, Benjamin Lok, Aditi Majumder and Dieter Schmalstieg, Piscataway, NJ, USA: IEEE , 2011, p. 27-24Conference paper (Refereed)
    Abstract [en]

    The parameter estimation variance of the Single Point Active Alignment Method (SPAAM) is studied through an experiment where 11 subjects are instructed to create alignments using an Optical See-Through Head Mounted Display (OSTHMD) such that three separate correspondence point distributions are acquired. Modeling the OSTHMD and the subject's dominant eye as a pinhole camera, findings show that a correspondence point distribution well distributed along the user's line of sight yields less variant parameter estimates. The estimated eye point location is studied in particular detail. Thefindings of the experiment are complemented with simulated datawhich show that image plane orientation is sensitive to the numberof correspondence points. The simulated data also illustrates someinteresting properties on the numerical stability of the calibrationproblem as a function of alignment noise, number of correspondencepoints, and correspondence point distribution.

  • 92.
    Axholt, Magnus
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA).
    Skoglund, Martin
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Peterson, Stephen
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA).
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA).
    Schön, Thomas
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Gustafsson, Fredrik
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA).
    Ellis, Stephen
    NASA Ames Research Center, USA.
    Optical See-Through Head Mounted Display: Direct Linear Transformation Calibration Robustness in the Presence of User Alignment Noise2010Report (Other academic)
    Abstract [en]

    The correct spatial registration between virtual and real objects in optical see-through augmented reality implies accurate estimates of the user’s eyepoint relative to the location and orientation of the display surface. A common approach is to estimate the display parameters through a calibration procedure involving a subjective alignment exercise. Human postural sway and targeting precision contribute to imprecise alignments, which in turn adversely affect the display parameter estimation resulting in registration errors between virtual and real objects. The technique commonly used has its origin incomputer vision, and calibrates stationary cameras using hundreds of correspondence points collected instantaneously in one video frame where precision is limited only by pixel quantization and image blur. Subsequently the input noise level is several order of magnitudes greater when a human operator manually collects correspondence points one by one. This paper investigates the effect of human alignment noise on view parameter estimation in an optical see-through head mounted display to determine how well astandard camera calibration method performs at greater noise levels than documented in computer vision literature. Through Monte-Carlo simulations we show that it is particularly difficult to estimate the user’s eyepoint in depth, but that a greater distribution of correspondence points in depth help mitigate the effects of human alignment noise.

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  • 93.
    Axholt, Magnus
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Skoglund, Martin
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Peterson, Stephen
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Schön, Thomas
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Gustafsson, Fredrik
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Ellis, Stephen
    NASA Ames Research Center, USA.
    Optical See-Through Head Mounted Display: Direct Linear Transformation Calibration Robustness in the Presence of User Alignment Noise2010In: Proceedings of the 54th Annual Meeting of the Human Factors and Ergonomics Society, 2010Conference paper (Refereed)
    Abstract [en]

    The correct spatial registration between virtual and real objects in optical see-through augmented reality implies accurate estimates of the user’s eyepoint relative to the location and orientation of the display surface. A common approach is to estimate the display parameters through a calibration procedure involving a subjective alignment exercise. Human postural sway and targeting precision contribute to imprecise alignments, which in turn adversely affect the display parameter estimation resulting in registration errors between virtual and real objects. The technique commonly used has its origin incomputer vision, and calibrates stationary cameras using hundreds of correspondence points collected instantaneously in one video frame where precision is limited only by pixel quantization and image blur. Subsequently the input noise level is several order of magnitudes greater when a human operator manually collects correspondence points one by one. This paper investigates the effect of human alignment noise on view parameter estimation in an optical see-through head mounted display to determine how well astandard camera calibration method performs at greater noise levels than documented in computer vision literature. Through Monte-Carlo simulations we show that it is particularly difficult to estimate the user’s eyepoint in depth, but that a greater distribution of correspondence points in depth help mitigate the effects of human alignment noise.

  • 94.
    Backenhof, Albert
    Linköping University, Department of Science and Technology, Media and Information Technology.
    Automatic Generation of Collision Hulls for Polygonal Objects2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Physics in interactive environments, such as computer games, and simulations require well madeand accurate bounding volumes in order to act both realistically and fast. Today it is common to useeither inaccurate boxes or spheres as bounding volumes or to model the volume by hand. Thesemethods are either too inaccurate or require too much time to ever be able to be used in real-time,accurate virtual environments.This thesis presents a method to automatically generate collision hulls for both manifolds and nonmanifolds.This allows meshes to be used in a physical environment in just a few seconds and stillbeing able to behave realistically. The method performs Approximate Convex Decomposition byiteratively dividing the mesh into smaller, more convex parts. Every part is wrapped in a convexhull. Together the hulls make an accurate, but low cost, convex representation of the original mesh.The convex hulls are stored in a bounding volume hierarchy tree structure that enables fast testingfor collision with the mesh.

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  • 95.
    Bae, S. Sandra
    et al.
    Univ Colorado, CO 80309 USA.
    Fujiwara, Takanori
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Do, Ellen Yi-Luen
    Univ Colorado, CO 80309 USA.
    Rivera, Michael L.
    Univ Colorado, CO 80309 USA.
    Szafir, Danielle Albers
    Univ North Carolina Chapel Hill, NC USA.
    A Computational Design Pipeline to Fabricate Sensing Network Physicalizations2024In: IEEE Transactions on Visualization and Computer Graphics, ISSN 1077-2626, E-ISSN 1941-0506, Vol. 30, no 1, p. 913-923Article in journal (Refereed)
    Abstract [en]

    Interaction is critical for data analysis and sensemaking. However, designing interactive physicalizations is challenging as it requires cross-disciplinary knowledge in visualization, fabrication, and electronics. Interactive physicalizations are typically produced in an unstructured manner, resulting in unique solutions for a specific dataset, problem, or interaction that cannot be easily extended or adapted to new scenarios or future physicalizations. To mitigate these challenges, we introduce a computational design pipeline to 3D print network physicalizations with integrated sensing capabilities. Networks are ubiquitous, yet their complex geometry also requires significant engineering considerations to provide intuitive, effective interactions for exploration. Using our pipeline, designers can readily produce network physicalizations supporting selection-the most critical atomic operation for interaction-by touch through capacitive sensing and computational inference. Our computational design pipeline introduces a new design paradigm by concurrently considering the form and interactivity of a physicalization into one cohesive fabrication workflow. We evaluate our approach using (i) computational evaluations, (ii) three usage scenarios focusing on general visualization tasks, and (iii) expert interviews. The design paradigm introduced by our pipeline can lower barriers to physicalization research, creation, and adoption.

  • 96.
    Baeuerle, A.
    et al.
    Ulm Univ, Germany.
    van Onzenoodt, C.
    Ulm Univ, Germany.
    der Kinderen, S.
    Ulm Univ, Germany.
    Johansson Westberg, Jimmy
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Jönsson, Daniel
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. Ulm Univ, Germany.
    Ropinski, T.
    Ulm Univ, Germany.
    Where did my Lines go? Visualizing Missing Data in Parallel Coordinates2022In: Computer graphics forum (Print), ISSN 0167-7055, E-ISSN 1467-8659, Vol. 41, no 3, p. 235-246Article in journal (Refereed)
    Abstract [en]

    We evaluate visualization concepts to represent missing values in parallel coordinates. We focus on the trade-off between the ability to perceive missing values and the concepts impact on common tasks. For this purpose, we identified three missing value representation concepts: removing line segments where values are missing, adding a separate, horizontal axis onto which missing values are projected, and using imputed values as a replacement for missing values. For the missing values axis and imputed values concepts, we additionally add downplay and highlight variations. We performed a crowd-sourced, quantitative user study with 732 participants comparing the concepts and their variations using five real-world datasets. Based on our findings, we provide suggestions regarding which visual encoding to employ depending on the task at focus.

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  • 97.
    Bahaghighat, Mahdi
    et al.
    Imam Khomeini Int Univ, Iran.
    Abedini, Fereshteh
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. Amirkabir Univ Technol, Iran.
    Xin, Qin
    Univ Faroe Isl, Faroe Islands.
    Zanjireh, Morteza Mohammadi
    Imam Khomeini Int Univ, Iran.
    Mirjalili, Seyedali
    Torrens Univ Australia, Australia; Yonsei Univ, South Korea.
    Using machine learning and computer vision to estimate the angular velocity of wind turbines in smart grids remotely2021In: Energy Reports, E-ISSN 2352-4847, Vol. 7, p. 8561-8576Article in journal (Refereed)
    Abstract [en]

    Today, power generation from clean and renewable resources such as wind and solar is of great salience. Smart grid technology efficiently responds to the increasing demand for electric power. Intelligent monitoring, control, and maintenance of wind energy facilities are indispensable to increase the performance and efficiency of smart grids (SGs). Integration of state-of-the-art machine learning algorithms and vision sensor networks approaches pave the way toward enhancing the wind farms performance. The generating power in a wind turbine farm is the most critical parameter that should be measured accurately. Produced power is highly related to weather patterns, and a new farm in a near area is also likely to have similar energy generation. Therefore, accurate and perpetual prediction models of the existing wind farms can be led to develop new stations with lower costs. The paper aims to estimate the angular velocity of turbine blades using vision sensors and signal processing. The high wind in the wind farm can cause the camera to vibrate in successive frames, and the noise in the input images can also strengthen the problem. Thanks to couples of solid computer vision algorithms, including FAST (Features from Accelerated Segment Test), SIFT (Scale-Invariant Feature Transform), SURF (Speeded Up Robust Features), BF (Brute-Force), FLANN (Fast Library for Approximate Nearest Neighbors), AE (Autoencoder), and SVM (support vector machines), this paper accurately localizes the Hub and track the presence of the Blade in consecutive frames of a video stream. The simulation results show that determining the hub location and the blade presence in sequential frames results in an accurate estimation of wind turbine angular velocity with 95.36% accuracy. (C) 2021 The Authors. Published by Elsevier Ltd.

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  • 98. Banissi, Ebad
    et al.
    Bertschi, StefanBurkhard, RemoCounsell, JohnDastbaz, MohammadEppler, MartinForsell, CamillaLinköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.Johansson, JimmyJern, MikaelGrinstein, GeorgeMarchese, FrancisMaple, CarstenLaing, RichardCvek, UrsakaTruschl, MarjanStuart, LizUrsun, AnnaWyeld, Theodor
    Information Visualization2010Conference proceedings (editor) (Other academic)
  • 99. Banissi, Ebad
    et al.
    Bertschi, StefanBurkhard, RemoCvek, UrskaEppler, MartinForsell, CamillaLinköping University, Department of Science and Technology, Media and Information Technology.Grinstein, GeorgesJohansson, JimmyLinköping University, Department of Science and Technology, Media and Information Technology.Kenderdine, SarahMarchese, Francis T.Maple, CarstenTrutschl, MarjamSarfraz, MuhammadStuart, LizUrsyn, AnnaWyeld, Theodor G.
    Information Visualization2011Conference proceedings (editor) (Refereed)
  • 100.
    Bankell, Evelyn
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Development and Evaluation of an Interactive Map-Based File Transfer Monitor2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis aims to investigate whether a map-based visualization of real-time file transfers can provide an overview and facilitate the workflow for the employees at Filmgate, a VFX company. In particular, how the interface should be implemented to provide a quick and easy overview as well as without being perceived as distracting or cluttered. This thesis describes the work process of designing, developing, and evaluating a web application to visualize file transfers between employees and remote workers located around the world.

    To receive theoretical knowledge, a prestudy was carried out that consisted of a literature study within information visualization with a focus on spatio-temporal data, design principles for creating a user-centered interface, and different evaluation methods. The prestudy also consisted of data exploration to fully understand the provided data and creating a low-fidelity prototype.

    The map-based file transfer monitor was implemented to visualize the real-time data, where the development was carried out in React.js with OpenStreetMap together with Leaflet to obtain an interactive map. Furthermore, the complementary charts were implemented in d3.js. To evaluate the map-based visualization method, two different user tests were performed, one quantitative in the middle of the development process and one qualitative at the end. The quantitative test consisted of a form and the qualitative test was based on interviews with task-driven questions.

    The result of this thesis presents a visualization method where real-time file transfers are displayed on a world map with a user-centered interface. All decisions regarding the application are based on theories contained in scientific articles. Finally, a discussion is given on how the result relates to the theory, pros, and cons of the method as well as future work and the work in a wider context. This thesis shows that a map-based visualization of file transfers can facilitate the workflow as various problems with the transfers can be detected at an early stage through either color-coding, error messages, or by observing the bandwidth. The visualization provides a good overview of the progression by emphasizing essential details on the map and demand details on demand. To prevent the map from getting disruptive and cluttered, objects are clustered based on their geographical coordinates.

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