liu.seSök publikationer i DiVA
Ändra sökning
Avgränsa sökresultatet
12 1 - 50 av 70
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Hassan, Kahin Akram
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Rönnberg, Niklas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Forsell, Camilla
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Johansson, Jimmy
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Centrum för klimatpolitisk forskning, CSPR.
    A Study on 2D and 3D Parallel Coordinates for Pattern Identification in Temporal Multivariate Data2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Parallel coordinates are commonly used for non-temporal multivariate data, but there is little support for their usability for displaying temporal multivariate data. In this paper, we introduce a study evaluating the usability of 2D and 3D parallel coordinates for pattern identification in temporal multivariate data. The results indicate that 3D parallel coordinates have higher usability, as measured with higher accuracy and faster response time as well as subjective ratings, compared to 2D.

  • 2.
    Muthumanickam, Prithiviraj
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Vrotsou, Katerina
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Vitoria, Aida
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Johansson, Jimmy
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Centrum för klimatpolitisk forskning, CSPR.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Identification of Temporally Varying Areas of Interest in Long-Duration Eye-Tracking Data Sets2018Ingår i: IEEE Transactions on Visualization and Computer Graphics, ISSN 1077-2626, E-ISSN 1941-0506Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Eye-tracking has become an invaluable tool for the analysis of working practices in many technological fields of activity. Typically studies focus on short tasks and use static expected areas of interest (AoI) in the display to explore subjects’ behaviour, making the analyst’s task quite straightforward. In long-duration studies, where the observations may last several hours over a complete work session, the AoIs may change over time in response to altering workload, emergencies or other variables making the analysis more difficult. This work puts forward a novel method to automatically identify spatial AoIs changing over time through a combination of clustering and cluster merging in the temporal domain. A visual analysis system based on the proposed methods is also presented. Finally, we illustrate our approach within the domain of air traffic control, a complex task sensitive to prevailing conditions over long durations, though it is applicable to other domains such as monitoring of complex systems. 

  • 3.
    Hassan, Kahin Akram
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Johansson, Jimmy
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Forsell, Camilla
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Rönnberg, Niklas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    On the Use of Parallel Coordinates for Temporal Multivariate Data2017Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    This work presents the results from a user centered evaluation of visual representations of temporal multivariate data using 2D and3D parallel coordinates. The objective of the evaluation was to investigate whether 2D or 3D representations increase user performance when the data consists of temporal multivariate data and the visual representation contains interactive user tools. The results show that the 3D parallel coordinates representation outperforms 2D parallel coordinates with regards to both accuracy and response time.This result is of interest to the information visualization community, since it shows the usefulness of visual representations of temporal multivariate data.

  • 4.
    Muthumanickam, Prithiviraj
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Vrotsou, Katerina
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Johansson, Jimmy
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Shape Grammar Extraction for Efficient Query-by-Sketch Pattern Matching in Long Time Series2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    Long time-series, involving thousands or even millions of time steps, are common in many application domains but remain very difficult to explore interactively. Often the analytical task in such data is to identify specific patterns, but this is a very complex and computationally difficult problem and so focusing the search in order to only identify interesting patterns is a common solution. We propose an efficient method for exploring user-sketched patterns, incorporating the domain expert’s knowledge, in time series data through a shape grammar based approach. The shape grammar is extracted from the time series by considering the data as a combination of basic elementary shapes positioned across different am- plitudes. We represent these basic shapes using a ratio value, perform binning on ratio values and apply a symbolic approximation. Our proposed method for pattern matching is amplitude-, scale- and translation-invariant and, since the pattern search and pattern con- straint relaxation happen at the symbolic level, is very efficient permitting its use in a real-time/online system. We demonstrate the effectiveness of our method in a case study on stock market data although it is applicable to any numeric time series data.

  • 5.
    Muthumanickam, Prithiviraj
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Forsell, Camilla
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Vrotsou, Katerina
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Johansson, Jimmy
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Supporting Exploration of Eye Tracking Data: Identifying Changing Behaviour Over Long Durations2016Ingår i: BEYOND TIME AND ERRORS: NOVEL EVALUATION METHODS FOR VISUALIZATION, BELIV 2016, ASSOC COMPUTING MACHINERY , 2016, s. 70-77Konferensbidrag (Refereegranskat)
    Abstract [en]

    Visual analytics of eye tracking data is a common tool for evaluation studies across diverse fields. In this position paper we propose a novel user-driven interactive data exploration tool for understanding the characteristics of eye gaze movements and the changes in these behaviours over time. Eye tracking experiments generate multidimensional scan path data with sequential information. Many mathematical methods in the past have analysed one or a few of the attributes of the scan path data and derived attributes such as Area of Interest (AoI), statistical measures, geometry, domain specific features etc. In our work we are interested in visual analytics of one of the derived attributes of sequential data-the: AoI and the sequences of visits to these AoIs over time. In the case of static stimuli, such as images, or dynamic stimuli, like videos, having predefined or fixed AoIs is not an efficient way of analysing scan path patterns. The AoI of a user over a stimulus may evolve over time and hence determining the AoIs dynamically through temporal clustering could be a better method for analysing the eye gaze patterns. In this work we primarily focus on the challenges in analysis and visualization of the temporal evolution of AoIs. This paper discusses the existing methods, their shortcomings and scope for improvement by adopting visual analytics methods for event-based temporal data to the analysis of eye tracking data.

  • 6.
    Forsell, Camilla
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    An Introduction and Guide to Evaluation of Visualization Techniques Through User Studies2014Ingår i: Handbook of human centric visualization / [ed] Weidong Huang, New York: Springer, 2014, s. 285-313Kapitel i bok, del av antologi (Refereegranskat)
  • 7.
    Vrotsou, Katerina
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Ynnerman, Anders
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Are we what we do? Exploring group behaviour through user-defined event-sequence similarity2014Ingår i: Information Visualization, ISSN 1473-8716, E-ISSN 1473-8724, Vol. 13, nr 3, s. 232-247Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The study of human activity in space and time is an inherent part of human geography. In order to perform such studies, data on the time use of individuals, in terms of sequence and timing of performed activities, are collected and analysed. A common assumption when analysing individuals’ time use is that groups that exhibit similar background and demographic characteristics also display similarities in how they use their time to structure their daily lives. In this article, we set out to investigate the correctness of such assumptions. We propose a visual analytics process based on sequence similarity measures tailored to event-based data such as performed activity sequences. The process allows an analyst to retrieve similarly behaving records according to user-selected similarity preferences and interactively explore aspects of this similarity in a multiple linked-view environment.

  • 8.
    Johansson, Jimmy
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Forsell, Camilla
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    On the usability of three-dimensional display in parallel coordinates: Evaluating the efficiency of identifying two-dimensional relationships2014Ingår i: Information Visualization, ISSN 1473-8716, E-ISSN 1473-8724, Vol. 13, nr 1, s. 29-41Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In recent years, several different attempts have been made to extend the well-known technique of parallel coordinates using a three-dimensional display. This article presents an evaluation that investigates the performance of the three-dimensional parallel coordinates technique and compares it with standard, two-dimensional parallel coordinates for analysis of two-dimensional relationships. Three-dimensional parallel coordinates, based on parallel planes instead of parallel axes, have been used for many years within the information visualization community for a variety of applications. Despite its quite common use, no formal evaluation detailing its usefulness for different tasks has been conducted. The evaluation presented in this article is the first step towards determining the usefulness of this type of three-dimensional parallel coordinates. The study compared three-dimensional parallel coordinates, using two different axis configurations commonly seen in the literature, with standard two-dimensional parallel coordinates for identification of two-dimensional relationships between variables in multivariate data. This type of task and the relationships to be judged are known to be well supported by two-dimensional parallel coordinates and multi-relational three-dimensional parallel coordinates. The results show that for identification of two-dimensional relationships, two-dimensional parallel coordinates are superior to the three-dimensional extensions, in terms of both response time and accuracy. Subjective opinions were also in favour of two-dimensional parallel coordinates. This study adds to the much-needed body of work examining the usability of three-dimensional representations in information visualization and for what tasks and data a proposed method is or is not appropriate.

  • 9.
    Vrotsou, Katerina
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Bergqvist, Mathias
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Ellegård, Kajsa
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring. Linköpings universitet, Filosofiska fakulteten.
    PODD: A Portable Diary Data Collection System2014Ingår i: AVI '14 Proceedings of the 2014 International Working Conference on Advanced Visual Interfaces, New York: Association for Computing Machinery (ACM), 2014, s. 381-382Konferensbidrag (Refereegranskat)
    Abstract [en]

    Activity diaries are a powerful data source for studying the time use of individuals and for creating awareness of individuals' daily activity patterns. The presented project is concerned with the development of an easily accessible method for collecting and analyzing diary data which will be applicable across a wide range of industrial, governmental, social science and medical domains. The PODD (POrtable Diary Data collection) is composed of a smartphone application for data registration, a web interface for user registration and an administration system for configuring the application according to the focus of the data collection.

  • 10.
    Kocak, Umut
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Lundin Palmerius, Karljohan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Anisotropic Virtual Coupling with Energy-Based Deflection for Palpating Inhomogeneous Compliant Objects2013Ingår i: Proceedings of the IEEE World Haptics Conference, IEEE , 2013, s. 115-120Konferensbidrag (Refereegranskat)
    Abstract [en]

    Virtual coupling, a spring-damper system between the haptic probe and its virtual representation, the proxy, is one of the most common approaches for haptic rendering. We have extended the virtual coupling by updating the spring stiffness, sometimes used to simulate compliance of a material, depending on the direction between the proxy and the probe. This anisotropic variation of the stiffness is used in exploring inhomogeneities beneath the surface allowing detection of rigid structures even when they are obscured by another structure beneath the surface. In addition, we also compensate for the energy variation of the spring to maintain passivity and increase realism. User studies were performed to survey the success rate in the detection of obscured rigid bodies beneath the surface with the modified virtual coupling algorithm and the improvement of shape perception for sub-surface objects with the additional energy compensation term providing gradient information. We also discuss potential benefits of the proposed methods as basic extensions to well-known haptic rendering algorithms which are both simpler and yield improved performance over traditional deformation simulationtechniques.

  • 11.
    Kocak, Umut
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Lundin Palmerius, Karljohan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    High Resolution Enhancement in Deformation via Anisotropic Virtual Coupling2013Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Achieving sufficient realism in deformation simulations requires consideration  of complex physical properties. The computational burden of modelling these properties requires the use of low resolution meshes to attain real time interactive performance. Medical data such as MR and CT, on the other hand, have much higher resolutions than can be practically used in deformation simulations. This results in significant amount of information loss, degenerating the ability to perceive variations in the data, especially inhomogeneities. In this paper, we address this issue by employing surfacerendering algorithms which can provide high resolution information from beneath the surface. An experiment was performed in a scenario simulating inhomogeneities of bone structure under the skin. Results have shown significant improvement for detecting inhomogeneities within deformable data while palpating the surface.

  • 12.
    Kocak, Umut
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Lundin Palmerius, Karljohan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    An Error Analysis Model for Adaptive Deformation Simulation2012Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    With the widespread use of deformation simulations in medical applications, the realism of the force feedback has become an important issue. In order to reach real-time performance with sufficient realism the approach of adaptivity, solution of different parts of the system with different resolutions and refresh rates, has been commonly deployed. The change in accuracy resulting from the use of adaptivity, however, has been been paid scant attention in the deformation simulation field. Presentation of error metrics is rare, while more focus is given to the real-time stability. We propose an abstract pipeline to perform error analysis for different types of deformation techniques which can consider different simulation parameters. A case study is also performed using the pipeline, and the various uses of the error estimation are discussed.

  • 13.
    Forsell, Camilla
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Questionnaires for evaluation in information visualization2012Ingår i: BELIV '12 Proceedings of the 2012 BELIV Workshop: Beyond Time and Errors - Novel Evaluation Methods for Visualization, New York: ACM Press, 2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    The position taken in this paper is that the availability of standardized questionnaires specifically developed for measuring users' perception of usability in evaluation studies in information visualization would provide the community with an excellent additional instrument. The need for such an instrument is evident for several important reasons. Pursuing the development, validation and use of questionnaires will add significantly to the evidence base necessary for the community to guide the production of high-quality visualization techniques, facilitate adoption by users, promote successful commercialization and guide future research tasks.

  • 14.
    Kocak, Umut
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Palmerius, Karljohan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Forsell, Camilla
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    The Effect of the Stiffness Gradient on the Just Noticeable Difference between Surface Regions2012Ingår i: Haptics: Perception, Devices, Mobility, and Communication: International Conference, EuroHaptics 2012, Tampere, Finland, June 13-15, 2012. Proceedings, Part I / [ed] Poika Isokoski, Jukka Springare, Springer Berlin/Heidelberg, 2012, s. 282-292Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    This book and its companion volume, LNCS 7282 and 7283, constitute the refereed proceedings of the 8th International Conference, EuroHaptics 2012, held in Tampere, Finland, in June 2012. The 99 papers (56 full papers, 32 short papers, and 11 demo papers) presented were carefully reviewed and selected from 153 submissions. Part I contains the full papers whereas Part II contains the short papers and the demo papers.

  • 15.
    Axholt, Magnus
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Skoglund, Martin A.
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    O’Connell, Stephen D.
    Swedish Air Force Combat Simulation Center at the Swedish Defence Research Agency.
    Cooper, Matthew D.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Ellis, Stephen R.
    Human Systems Integration Division at NASA Ames Research Center.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Accuracy of Eyepoint Estimation in Optical See-Through Head-Mounted Displays Using the Single Point Active Alignment Method2011Konferensbidrag (Övrigt vetenskapligt)
    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.

  • 16.
    Kocak, Umut
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Lundin Palmerius, Karljohan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Forsell, Camilla
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Analysis of the JND of Stiness in Three Modesof Comparison2011Ingår i: HAID'11 Proceedings of the 6th international conference on Haptic and audio interaction design / [ed] Cooper, E., Brewster, S., Ogawa, H., Kryssanov, V.K., Springer Berlin/Heidelberg, 2011, s. 22-31Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Understanding and explaining perception of touch is a non-trivial task. Even seemingly trivial differences in exploration may potentially have a significant impact on perception and levels of discrimination. In this study, we explore different aspects of contact related to stiffness perception and their effects on the just noticeable difference (JND) of stiffness are surveyed. An experiment has been performed on non-deformable, compliant objects in a virtual environment with three different types of contact: Discontinuous pressure, continuous pressure and continuous lateral motion. The result shows a significantly better discrimination performance in the case of continuous pressure (a special case of nonlinearity), which can be explained by the concept of haptic memory. Moreover, it is found that the perception is worse for the changes that occur along the lateral axis than the normal axis.

  • 17.
    Axholt, Magnus
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Skoglund, Martin
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    O'Connell, Stephen
    Swedish Defence Research Agency.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Ellis, Stephen
    NASA Ames Research Center.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Parameter Estimation Variance of the Single Point Active Alignment Method in Optical See-Through Head Mounted Display Calibration2011Ingår i: Proceedings of the IEEE Virtual Reality Conference / [ed] Michitaka Hirose, Benjamin Lok, Aditi Majumder and Dieter Schmalstieg, Piscataway, NJ, USA: IEEE , 2011, s. 27-24Konferensbidrag (Refereegranskat)
    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.

  • 18.
    Vrotsou, Katerina
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Forsell, Camilla
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    2D and 3D Representations for Feature Recognition in Time Geographical Diary Data2010Ingår i: Information Visualization, ISSN 1473-8716, E-ISSN 1473-8724, Vol. 9, nr 4, s. 263-276Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Time geographical representations are becoming a common approach to analysing spatio-temporal data. Such representations appear intuitive in the process of identifying patterns and features as paths of populations form tracks through the 3D space, which can be seen converging and diverging over time. In this article, we compare 2D and 3D representations within a time geographical visual analysis tool for activity diary data. We identify a representative task and evaluate task performance between the two representations. The results show that the 3D representation has benefits over the 2D representation for feature identification but also indicate that these benefits can be lost if the 3D representation is not carefully constructed to help the user to see them.

  • 19.
    Vrotsou, Katerina
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Behaviour-driven clustering based on event-sequence similarity metrics2010Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    When analysing event data two key objectives are to first identify interesting subsequences in the data records and then to retrieve groups of records that exhibit similar behaviour. This is especially true when the focus of the exploration is the human, for example when using activity diaries to reveal sub-populations with similar behaviour, medical records to identify groups with similar medical conditions, or web sessions to find groups with similar web-surfing habits. In this paper we propose a visual exploration approach, based on sequence similarity metrics and clustering techniques, that will allow an analyst to interactively explore the distribution of sequences along event data records as well as group the results according to user-selected similarity preferences. We have identified a set of similarity metrics that are specific to event-sequences which we use as input into a clustering algorithm. The user can choose which metrics to use and assign weighting factors to them, which results in groupings that exhibit similar behaviour according to their definition of similarity and interestingness. The resulting clusters can be interactively explored in a multiple linked-view environment showing the clusters, the cluster quality, the similarity metrics and meta (background) information describing the clustered individuals in order to make comparisons within and between groups. Using such an interactive approach that considers user preferences and takes advantage of background knowledge gives a basis for enhanced analytical reasoning by providing a more complete understanding of the retrieved groupings and can lead to a more thorough analysis and accurate assessments.

  • 20.
    Peterson, Stephen D.
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Axholt, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Ellis, Stephen R.
    Human Systems Integration Division, NASA Ames Research Center, USA.
    Detection Thresholds for Label Motion in Visually Cluttered Displays2010Ingår i: IEEE Virtual Reality Conference (VR), 2010, Piscataway, NJ, USA: IEEE , 2010, s. 203-206Konferensbidrag (Refereegranskat)
    Abstract [en]

    While label placement algorithms are generally successful in managing visual clutter by preventing label overlap, they can also cause significant label movement in dynamic displays. This study investigates motion detection thresholds for various types of label movement in realistic and complex virtual environments, which can be helpful for designing less salient and disturbing algorithms. Our results show that label movement in stereoscopic depth is shown to be less noticeable than similar lateral monoscopic movement, inherent to 2D label placement algorithms. Furthermore, label movement can be introduced more readily into the visual periphery (over 15° eccentricity) because of reduced sensitivity in this region. Moreover, under the realistic viewing conditions that we used, motion of isolated labels is more easily detected than that of overlapping labels. This perhaps counterintuitive finding may be explained by visual masking due to the visual clutter arising from the label overlap. The quantitative description of the findings presented in this paper should be useful not only for label placement applications, but also for any cluttered AR or VR application in which designers wish to control the users’ visual attention, either making text labels more or less noticeable as needed.

  • 21.
    Cooper, Matthew
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Fridlund, Alexander
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Andel, Miroslav
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Bojan, Claudiu
    Eurocontrol, Luxembourg.
    Hardy, Jean-Luc
    Eurocontrol Experimental Centre, Brétigny.
    Educational Benefits of 3D Displays in Early Controller Training2010Ingår i: Proceedings of the 27th International Congress of the Aeronautical Sciences (ICAS2010) / [ed] Professor Ian Grant, 2010Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    There have been many attempts to exploit three- dimensional displays in Air Traffic Control where it has long been suspected that the 3D display may help to reduce the cognitive load on the controller by removing the need to construct an elaborate mental model of the air space and the traffic contained within it. 3D displays could allow the controller to simply re-interpret the presented information in real time without the need for them to construct this internal model and without the need to remember large amounts of complex information. This should result in controllers being able to manage larger numbers of aircraft without loss of safety, as well as reducing the pressure on controllers allowing for longer work sessions with less problems of mental fatigue.

    The purpose of this study has been to explore the use of 3D in controller training and, in this initial study, to examine the basic reaction of the controllers to 3D representations and the effects, if any, which the introduction of 3D has on their work.

  • 22.
    Axholt, Magnus
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer.
    Skoglund, Martin
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Peterson, Stephen
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer.
    Schön, Thomas
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Fredrik
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer.
    Ellis, Stephen
    NASA Ames Research Center, USA.
    Optical See-Through Head Mounted Display: Direct Linear Transformation Calibration Robustness in the Presence of User Alignment Noise2010Rapport (Övrigt vetenskapligt)
    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.

  • 23.
    Axholt, Magnus
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Skoglund, Martin
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Peterson, Stephen
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Schön, Thomas
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Fredrik
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Ellis, Stephen
    NASA Ames Research Center, USA.
    Optical See-Through Head Mounted Display: Direct Linear Transformation Calibration Robustness in the Presence of User Alignment Noise2010Ingår i: Proceedings of the 54th Annual Meeting of the Human Factors and Ergonomics Society, 2010Konferensbidrag (Refereegranskat)
    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.

  • 24.
    Klashed, Staffan
    et al.
    SCISS AB, Stockholm, Sweden.
    Hemingsson, Per
    SCISS AB, Stockholm, Sweden.
    Emmart, Carter
    American Museum of Natural History, New York, USA.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Uniview - Visualizing the Universe2010Ingår i: Eurographics 2010 - Areas Papers, Norrköping, Sweden: Eurographics Association , 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper describes the development of the software system, Uniview, the motivation behind some of the most prominent features of the system and the strengths and challenges of running a development project in such close collaboration with the users. Uniview is a sophisticated system for the visual display and exploration of the enormous and complex data which the human race has gathered about the universe. This beautiful, fascinating data, with it’s sheer size both in terms of data elements and the distances between the objects in the known universe, presents challenges to the developer at all levels: from basic rendering through representation and to data managment.

  • 25.
    Thong Dang, Nguyen
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Tavanti, Monica
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Rankin, Ivan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    A comparison of different input devices for a 3D environment2009Ingår i: INTERNATIONAL JOURNAL OF INDUSTRIAL ERGONOMICS, ISSN 0169-8141, Vol. 39, nr 3, s. 554-563Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a usability study comparing wand, voice, and two tablet-PC based interfaces across a task requiring three-dimensional surface exploration, information gathering and recall of information. The aim of this study was to identify a suitable interaction interface, among the ones implemented in a three-dimensional environment for Air Traffic Control, for interactive exploration of and gathering information about three-dimensional weather structures. Data concerning time, error rate, number of control actions as well as participants feedback on ease of learning, ease of use, frustration and perceived difficulty of the performed task were collected. The results indicate that the wand interface supported better performance when compared with the other interaction interfaces. Among the four interaction interfaces, the voice interface seems to present several limitations, mostly related to time lag in the voice recognition, which was judged by the subjects as a source of frustration.

  • 26.
    Vrotsou, Katerina
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Johansson, Jimmy
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    ActiviTree: Interactive Visual Exploration of Sequences in Event-Based Data Using Graph Similarity2009Ingår i: IEEE Transactions on Visualization and Computer Graphics, ISSN 1077-2626, E-ISSN 1941-0506, ISSN 1077-2626, Vol. 15, nr 6, s. 945-952Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The identification of significant sequences in large and complex event-based temporal data is a challenging problem with applications in many areas of todays information intensive society. Pure visual representations can be used for the analysis, but are constrained to small data sets. Algorithmic search mechanisms used for larger data sets become expensive as the data size increases and typically focus on frequency of occurrence to reduce the computational complexity, often overlooking important infrequent sequences and outliers. In this paper we introduce an interactive visual data mining approach based on an adaptation of techniques developed for web searching, combined with an intuitive visual interface, to facilitate user-centred exploration of the data and identification of sequences significant to that user. The search algorithm used in the exploration executes in negligible time, even for large data, and so no pre-processing of the selected data is required, making this a completely interactive experience for the user. Our particular application area is social science diary data but the technique is applicable across many other disciplines.

  • 27.
    Kocak, Umut
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Palmerius, Karljohan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Dynamic Deformation Using Adaptable, Linked Asynchronous FEM Regions2009Ingår i: Spring Conference on Computer Graphics / [ed] Helwig Hauser and Stephen N. Spencer, New York: ACM , 2009, s. 197-204Konferensbidrag (Refereegranskat)
    Abstract [en]

    In order to simulate both physically and visually realistic soft tissue deformations, the Finite Element Method (FEM) is the mostpopular choice in the literature. However it is non-trivial to modelcomplex behaviour of soft tissue with sufficient refresh rates, especiallyfor haptic force feedback which requires an update rate ofthe order of 1 kHz. In this study the use of asynchronous regions isproposed to speed up the solution of FEM equations in real-time. Inthis way it is possible to solve the local neighborhood of the contactwith high refresh rates, while evaluating the more distant regions atlower frequencies, saving computational power to model complexbehaviour within the contact area. Solution of the different regionsusing different methods is also possible. To attain maximum efficiencythe size of the regions can be changed, in real-time, in responseto the size of the deformation.

  • 28.
    Peterson, Stephen D.
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Axholt, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Ellis, Stephen R.
    NASA, Ames Research Center, USA.
    Evaluation of Alternative Label Placement Techniques in Dynamic Virtual Environments2009Ingår i: International Symposium on Smart Graphics, Berlin / Heidelberg: Springer , 2009, s. 43-55Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper reports on an experiment comparing label placement techniques in a dynamic virtual environment rendered on a stereoscopic display. The labeled objects are in motion, and thus labels need to continuously maintain separation for legibility. The results from our user study show that traditional label placement algorithms, which always strive for full label separation in the 2D view plane, produce motion that disturbs the user in a visual search task. Alternative algorithms maintaining separation in only one spatial dimension are rated less disturbing, even though several modifications are made to traditional algorithms for reducing the amount and salience of label motion. Maintaining depth separation of labels through stereoscopic disparity adjustments is judged theleast disturbing, while such separation yields similar user performance to traditional algorithms. These results are important in the design offuture 3D user interfaces, where disturbing or distracting motion due to object labeling should be avoided.

  • 29.
    Vrotsou, Katerina
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Ellegård, Kajsa
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring. Linköpings universitet, Filosofiska fakulteten.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Exploring time diaries using semi-automated activity pattern extraction2009Ingår i: electronic International Journal of Time Use Research (eIJTUR), Vol. 6, nr 1, s. 1-25Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Identifying patterns of activities in time diaries in order to understand the variety of daily life in terms of combinationsof activities performed by individuals in different groups is of interest in time use research. So far, activitypatterns have mostly been identified by visually inspecting representations of activity data or by using sequencecomparison methods, such as sequence alignment, in order to cluster similar data and then extract representativepatterns from these clusters. Both these methods are sensitive to data size, pure visual methods becometoo cluttered and sequence comparison methods become too time consuming. Furthermore, the patterns identifiedby both methods represent mostly general trends of activity in a population, while detail and unexpectedfeatures hidden in the data are often never revealed. We have implemented an algorithm that searches the timediaries and automatically extracts all activity patterns meeting user-defined criteria of what constitutes a validpattern of interest for the user’s research question. Amongst the many criteria which can be applied are a timewindow containing the pattern, minimum and maximum occurrences of the pattern, and number of people thatperform it. The extracted activity patterns can then be interactively filtered, visualized and analyzed to revealinteresting insights. Exploration of the results of each pattern search may result in new hypotheses which can besubsequently explored by altering the search criteria. To demonstrate the value of the presented approach weconsider and discuss sequential activity patterns at a population level, from a single day perspective.

  • 30.
    Lundin Palmerius, Karljohan
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Flow Field Visualization Using Vector Field Perpendicular Surfaces2009Ingår i: Proceedings of Spring Conference on Computer Graphics, Bratislava: Comenius University , 2009, s. 27-34Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper introduces Vector Field Perpendicular Surfaces as a means to represent vector data with special focus on variations across the vectors in the field. These surfaces are a perpendicular analogue to streamlines, with the vector data always being parallel to the normals of the surface. In this way the orientation of the data is conveyed to the viewer, while providing a continuous representation across the vectors of the field. This paper describes the properties of such surfaces including an issue with helicity density in the vector data, an approach to generating them, several stop conditions and special means to handle also fields with non-zero helicity density.

  • 31.
    Bivall Persson, Petter
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Höst, Gunnar E.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew D.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Tibell, Lena A. E.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Hälsouniversitetet.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Improved Feature Detection over Large Force Ranges Using History Dependent Transfer Functions2009Ingår i: Third Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environments and Teleoperator Systems, WorldHaptics 2009, IEEE , 2009, s. 476-481Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we present a history dependent transfer function (HDTF) as a possible approach to enable improved haptic feature detection in high dynamic range (HDR) volume data. The HDTF is a multi-dimensional transfer function that uses the recent force history as a selection criterion to switch between transfer functions, thereby adapting to the explored force range. The HDTF has been evaluated using artificial test data and in a realistic application example, with the HDTF applied to haptic protein-ligand docking. Biochemistry experts performed docking tests, and expressed that the HDTF delivers the expected feedback across a large force magnitude range, conveying both weak attractive and strong repulsive protein-ligand interaction forces. Feature detection tests have been performed with positive results, indicating that the HDTF improves the ability of feature detection in HDR volume data as compared to a static transfer function covering the same range.

  • 32.
    Tavanti, Monica
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew D.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Looking for the 3D Picture: The Spatio-temporal Realm of Student Controllers2009Ingår i: Human Centered Design: First International Conference, HCD 2009, Held as Part of HCI International 2009, San Diego, CA, USA, July 19-24, 2009 Proceedings (Book part VII) / [ed] Masaaki Kurosu, Springer Berlin/Heidelberg, 2009, Vol. 5619, s. 1070-1079Konferensbidrag (Refereegranskat)
    Abstract [en]

    Employing three-dimensional displays in Air Traffic Control (ATC) has been the object of study and debates for numerous years. Although empirical studies have often led to mixed results, some preliminary evidence suggests that training could be a suitable domain of application for 3D interfaces. Little evidence, however, is available to fully support this claim. We attempted to fill this gap with a project that aims at studying and evaluating 3D displays for ATC training purposes. This paper describes the first steps of this project, by reporting and discussing the results of a study aiming at understanding whether ATC trainees form a three-dimensional image of air traffic and at comprehending what the nature of this 3D picture is.

  • 33.
    Lind, Mats
    et al.
    Department of Information Science, Uppsala University, Sweden.
    Johansson, Jimmy
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Many-to-Many Relational Parallel Coordinates Displays2009Ingår i: Information Visualisation: IV 2009 / [ed] Ebad Banissi et al., Los Alamitos, CA, USA: IEEE Computer Society, 2009, s. 25-31Konferensbidrag (Refereegranskat)
    Abstract [en]

    An interesting property of the commonly used parallel coordinates display is the distinct overall pattern formed by the totality of lines between adjacent axes. These patterns have a direct correspondence to the type of relationship existing between the variables mapped onto the axes in question as well as a salient visual appearance. Parallel coordinates displays can therefore be used to visually investigate relationships between variables as well as investigating individual objects/lines. The problem with this approach is that, whereas each object is mapped in its entirety in a standard parallel coordinates display, only a small subset of the interrelations between variables is shown as the number of variables increase. To show all possible relations between variables multiple parallel coordinates displays are needed. In turn this means that each variable is duplicated several times, once per extra parallel coordinates display. To a viewer this increases the visual complexity and most probably the mental load. To aid users we have devised a new configuration of the axes in multiple parallel coordinates displays. Through an experiment we have also started to investigate the usability of this new configuration and the results are promising.

  • 34.
    Peterson, Stephen D.
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Axholt, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Ellis, Stephen R.
    NASA Ames Research Center, USA.
    Visual Clutter Management in Augmented Reality: Effects of Three Label Separation Methods on Spatial Judgments2009Ingår i: IEEE Symposium on 3D User Interfaces (3DUI), Lafayette (LA), USA: IEEE , 2009, s. 111-118Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper reports an experiment comparing three label separation methods for reducing visual clutter in Augmented Reality (AR) displays. We contrasted two common methods of avoiding visual overlap by moving labels in the 2D view plane with a third that distributes overlapping labels in stereoscopic depth. The experiment measured user identification performance during spatial judgment tasks in static scenes. The threemethods were compared with a control condition in which no label separation method was employed. The results showed significant performance improvements, generally 15-30%, for all three methods over the control; however, these methods were statistically indistinguishable from each other. In-depth analysis showed significant performance degradation when the 2D view plane methods produced potentially confusing spatial correlations between labels and the markers they designate. Stereoscopically separated labels were subjectively judged harder to read than view-plane separated labels. Since measured performance was affected both by label legibility and spatial correlation of labels and their designated objects, it is likely that the improved spatial correlation of stereoscopically separated labels and their designated objects has compensated for poorer stereoscopic text legibility. Future testing with dynamic scenes is expected to more clearly distinguish the three label separation techniques.

  • 35.
    Johansson, Jimmy
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    A screen space quality method for data abstraction2008Ingår i: Computer graphics forum (Print), ISSN 0167-7055, E-ISSN 1467-8659, Vol. 27, nr 3, s. 1039-1046Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The rendering of large data sets can result in cluttered displays and non-interactive update rates, leading to time consuming analyses. A straightforward solution is to reduce the number of items, thereby producing an abstraction of the data set. For the visual analysis to remain accurate, the graphical representation of the abstraction must preserve the significant features present in the original data. This paper presents a screen space quality method, based on distance transforms, that measures the visual quality of a data abstraction. This screen space measure is shown to better capture significant visual structures in data, compared with data space measures. The presented method is implemented on the GPU, allowing interactive creation of high quality graphical representations of multivariate data sets containing tens of thousands of items. © 2008 The Eurographics Association and Blackwell Publishing Ltd.

  • 36.
    Lundin Palmerius, Karljohan
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Haptic Rendering of Dynamic Volumetric Data2008Ingår i: IEEE Transactions on Visualization and Computer Graphics, ISSN 1077-2626, E-ISSN 1941-0506, Vol. 14, nr 2, s. 263-276Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With current methods for volume haptics in scientific visualization, features in time-varying data can freely move straight through the haptic probe without generating any haptic feedback-the algorithms are simply not designed to handle variation with time but consider only the instantaneous configuration when the haptic feedback is calculated. This article introduces haptic rendering of dynamic volumetric data to provide a means for haptic exploration of dynamic behavior in volumetric data. We show how haptic feedback can be produced that is consistent with volumetric data moving within the virtual environment and with data that, in itself, evolves over time. Haptic interaction with time-varying data is demonstrated by allowing palpation of a computerized tomography sequence of a beating human heart.

  • 37.
    Johansson, Jimmy
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Forsell, Camilla
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Lind, Mats
    Uppsala University.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Perceiving Patterns in Parallel Coordinates: Determining Thresholds for Identification of Relationships2008Ingår i: Information Visualization, ISSN 1473-8716, E-ISSN 1473-8724, Vol. 7, nr 2, s. 152-162Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article presents a study that investigates the ability of humans to perceive relationships (patterns) in parallel coordinates, an ability that is crucial to the use of this popular visualization technique. It introduces a visual quality metric, acceptable distortions of patterns, which establishes the level of noise that may be present in data while allowing accurate identification of patterns. This metric was used to assess perceptual performance of standard 2D parallel coordinates and multi-relational 3D parallel coordinates in two experiments. In multi-relational 3D parallel coordinates the axes are placed on a circle with a focus axis in the centre, allowing a simultaneous analysis between the focus variable and all other variables. The experiments aimed to determine the maximum number of variables that can be, from a user's point of view, efficiently used in a multi-relational 3D parallel coordinates display and to present a first attempt to study users' ability to analyse noisy data in parallel coordinates. The results show that, in terms of the acceptable level of noise in data, a multi-relational 3D parallel coordinates visualization having 11 axes (variables) is as efficient as standard 2D parallel coordinates. Visualizing a larger number of variables would possibly require a greater amount of manipulation of the visualization and thus be less efficient.

  • 38.
    Vrotsou, Katerina
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew D.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Seeing Beyond Statistics: Visual Exploration of Productivity on a Construction Site2008Ingår i: Vis 2008, Visualisation: Visualisation in Built and Rural Enviroments, Los Alamitos, CA, USA: IEEE Computer Society, 2008, s. 37-42Konferensbidrag (Refereegranskat)
    Abstract [en]

    Work on the construction site is known to be inefficient due to workers spending much time waiting for materials, transporting materials and from frequent interruptions of tasks. Studies on the construction site typically use statistical measures to analyse the sampled data about work and such measures, while very useful, can overlook important features of the data. In this paper we apply a previously developed approach, derived from Time Geographical methods, to visually represent the sampled construction productivity data and show that this method may enable the analyst to better understand the distribution of activities, and how they are interrelated and dependent upon each other. 

  • 39.
    Dang, Nguyen Thong
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Tavanti, Monica
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Rankin, Ivan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    A comparison of different input devices for a 3D environment2007Ingår i: European Conference on Cognitive Ergonomics 2007,2007, London: ACM Press , 2007, s. 153-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Motivation - To identify a suitable interaction modality -among the ones currently implemented in a three-dimensional (3D) environment for Air Traffic Control- for allowing interactive exploration of and gathering information about 3D weather structures. Research approach - A usability study entailing four interaction modalities (also called -interaction interfaces-): voice, wand, pen and sketch interfaces, across a task requiring 3D surface exploration, information gathering and recall of information. Quantitative data (time, errors and a composite performance index) as well as qualitative data were collected. Findings/Design - Overall, the results indicate that the wand supported a better performance when compared to the other interaction interfaces. Among the four interaction interfaces, the voice interface seems to present additional limitations, mostly related to time lag in the voice recognition, that were judged as a source of frustration. Originality/Value - The present work provides empirical results deriving from a comparative usability study of four interaction interfaces; it contributes to the study of interaction in 3D environments with new empirical data.

  • 40.
    Johansson, Jimmy
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Ljung, Patric
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Depth Cues and Density in Temporal Parallel Coordinates2007Ingår i: EUROVIS'07 Proceedings of the 9th Joint Eurographics / IEEE VGTC Symposium on Visualization, Aire-la-Ville, Switzerland: Eurographics - European Association for Computer Graphics, 2007, s. 35-42Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    This paper introduces Temporal Density Parallel Coordinates (TDPC) and Depth Cue Parallel Coordinates (DCPC) which extend the standard 2D parallel coordinates technique to capture time-varying dynamics. The proposed techniques can be used to analyse temporal positions of data items as well as temporal positions of changes occurring using 2D displays. To represent temporal changes, polygons (instead of traditional lines) are rendered in parallel coordinates. The results presented show that rendering polygons is superior at revealing large temporal changes. Both TDPC and DCPC have been efficiently implemented on the GPU allowing the visualization of thousands of data items over thousands of time steps at interactive frame rates.

  • 41.
    Johansson, Jimmy
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Ljung, Patric
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Depth Cues and Density in Temporal Parallel Coordinates2007Ingår i: Proceedings of Eurographics/IEEE VGTC Symposium on Visualization, Norrköping, Sweden, Aire-la-Ville, Switzerland: Eurographics Association , 2007, s. 35-42Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    This paper introduces Temporal Density Parallel Coordinates (TDPC) and Depth Cue Parallel Coordinates (DCPC) which extend the standard 2D parallel coordinates technique to capture time-varying dynamics. The proposed techniques can be used to analyse temporal positions of data items as well as temporal positions of changes occurring using 2D displays. To represent temporal changes, polygons (instead of traditional lines) are rendered in parallel coordinates. The results presented show that rendering polygons is superior at revealing large temporal changes. Both TDPC and DCPC have been efficiently implemented on the GPU allowing the visualization of thousands of data items over thousands of time steps at interactive frame rates.

  • 42.
    Bivall Persson, Petter
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Tibell, Lena
    Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för medicinsk cellbiologi. Linköpings universitet, Hälsouniversitetet.
    Ainsworth, Shaaron
    Learning Sciences Research Institute, University of Nottingham, Nottingham, UK.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Jonsson, Bengt-Harald
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär Bioteknik. Linköpings universitet, Tekniska högskolan.
    Designing and Evaluating a Haptic System for Biomolecular Education2007Ingår i: IEEE Virtual Reality Conference, 2007. VR '07. / [ed] Sherman, W; Lin, M; Steed, A, Piscataway, NJ, USA: IEEE , 2007, s. 171-178Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we present an in situ evaluation of a haptic system, with a representative test population, we aim to determine what, if any, benefit haptics can have in a biomolecular education context. We have developed a haptic application for conveying concepts of molecular interactions, specifically in protein-ligand docking. Utilizing a semi-immersive environment with stereo graphics, users are able to manipulate the ligand and feel its interactions in the docking process. The evaluation used cognitive knowledge tests and interviews focused on learning gains. Compared with using time efficiency as the single quality measure this gives a better indication of a system's applicability in an educational environment. Surveys were used to gather opinions and suggestions for improvements. Students do gain from using the application in the learning process but the learning appears to be independent of the addition of haptic feedback. However the addition of force feedback did decrease time requirements and improved the students understanding of the docking process in terms of the forces involved, as is apparent from the students' descriptions of the experience. The students also indicated a number of features which could be improved in future development.

  • 43.
    Lundin (Palmerius), Karljohan
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Persson, Anders
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och vård, Medicinsk radiologi. Östergötlands Läns Landsting, Bildmedicinskt centrum, Avdelningen för radiologi US. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Evestedt, Daniel
    SenseGraphics AB.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Enabling design and interactive selection of haptic modes2007Ingår i: Virtual Reality, ISSN 1359-4338, E-ISSN 1434-9957Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The ever increasing size and complexity of volumetric data in a wide range of disciplines makes it useful to augment volume visualization tools with alternative modalities. Studies have shown that introducing haptics can significantly increase both exploration speed and precision. It is also capable of conveying material properties of data and thus has great potential to improve user performance in volume data exploration. In this paper we describe how recent advances in volume haptics can be used to build haptic modes-building blocks for haptic schemes. These modes have been used as base components of a toolkit allowing for more efficient development of haptic prototypes and applications. This toolkit allows interactive construction, configuration and fine-tuning of both visual and haptic representations of the data. The technology is also used in a pilot study to determine the most important issues and aspects in haptic volume data interaction and exploration, and how the use of haptic modes can facilitate the implementation of effective haptic schemes.

  • 44.
    Vrotsou, Katerina
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Ellegård, Kajsa
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring. Linköpings universitet, Filosofiska fakulteten.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Everyday Life Discoveries: Mining and Visualizing Activity Patterns in Social Science Diary Data2007Ingår i: IEEE International Conference on Information Visualisation,2007: ISSN 1550-6037 / [ed] Ebad Banissi, Remo Aslak Burkhard, Georges Grinstein, Urska Cvek, Marjan Trutschl, Liz Stuart, Theodor G Wyeld, Gennady Andrienko, Jason Dykes, Mikael Jern, Dennis Groth and Anna Ursyn, Los Alamitos, CA, USA: IEEE , 2007, s. 130-138Konferensbidrag (Refereegranskat)
    Abstract [en]

    The ability to identify and examine patterns of activities is a key tool for social and behavioural science. In the past this has been done by statistical or purely visual methods but automated sequential pattern analysis through sophisticated data mining and visualization tools for pattern location and evaluation can open up new possibilities for interactive exploration of the data. This paper describes the addition of a sequential pattern identification method to the visual activity-analysis tool, VISUAL-TimePAcTS, and its effectiveness in the process of pattern analysis in social science diary data. The results have shown that the method correctly identifies patterns and conveys them effectively to the social scientist in a manner that allows them quick and easy understanding of the significance of the patterns.

  • 45.
    Tibell, Lena
    et al.
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för medicinsk cellbiologi.
    Bivall Persson, Petter
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Jonsson, Bengt-Harald
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär Bioteknik.
    Experience the Aperceptual through Virtual Reality! Tactile and Visual VR Representations as Cognitive Tools in Molecular Life Science2007Ingår i: ESERA 2007, 2007Konferensbidrag (Övrigt vetenskapligt)
  • 46.
    Vrotsou, Katerina
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Ellegård, Kajsa
    Linköpings universitet, Filosofiska fakulteten. Linköpings universitet, Institutionen för tema, Tema teknik och social förändring.
    Cooper, Matthew D.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Exploring Time Diaries Using Semi-Automated Activity Pattern Extraction2007Ingår i: IATUR - XXIX Annual Conference,2007, 2007Konferensbidrag (Refereegranskat)
  • 47.
    Bivall Persson, Petter
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer.
    Tibell, Lena
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för medicinsk cellbiologi.
    Cooper, Matthew D.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Ainsworth, Shaaron
    Learning Sciences Research Institute University of Nottingham.
    Reasoning through Touch? Using Haptics in Life Science Education2007Ingår i: EARLI 2007 12th Biennial Conference for Research on Learning and Instruction, 2007Konferensbidrag (Övrigt vetenskapligt)
  • 48.
    Bivall Persson, Petter
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Jonsson, Bengt-Harald
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär Bioteknik.
    Tibell, Lena
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för medicinsk cellbiologi.
    Use of Chemical Force Feedback for Multisensory Insights into Ligand Docking2007Ingår i: VII European Symposium of The Protein Society: From Proteins to Proteome, 2007, s. 151-151Konferensbidrag (Refereegranskat)
  • 49.
    Bivall Persson, Petter
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Tibell, Lena
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för medicinsk cellbiologi.
    Visuella och haptiska modeller för underlättad förståelse för molekylers struktur och interaktioner2007Ingår i: 10:e Universitetspedagogiska konferensen vid Linköpings universitet: Pedagogiska utmaningar i tiden / [ed] Helene Hård af Segerstad, 2007, s. 43-47Konferensbidrag (Refereegranskat)
  • 50.
    Dang, Nguyen Thong
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för teknik och naturvetenskap.
    Cooper, Matthew D.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Visuell informationsteknologi och applikationer. Linköpings universitet, Tekniska högskolan.
    Bourgois, Marc
    EUROCONTROL Experimental Centre, France.
    A Survey on Controller Weather Information Needs and 3D Weather Visualization2006Ingår i: EUROCONTROL Innovative Research Workshop,2006, Bruxelles, BE: EUROCONTROL , 2006, s. 69-79Konferensbidrag (Övrigt vetenskapligt)
12 1 - 50 av 70
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf