| 1. |
- Aigner, Wolfgang, et al.
(författare)
-
Workshop on Audio-Visual Analytics
- 2022
-
Ingår i: PROCEEDINGS OF THE WORKING CONFERENCE ON ADVANCED VISUAL INTERFACES AVI 2022. - New York, NY, USA : ASSOC COMPUTING MACHINERY. - 9781450397193
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Konferensbidrag (refereegranskat)abstract
- In their daily lives, people use more than one sense to perceive and interpret their environment. Likewise, audio-visual interfaces can support human data analysts better than interfaces relying on just one sense. While the research communities of sonification and visualization have both carried out extensive research on the auditory and visual representation of data, comparatively little is known about their systematic and complementary combination for data analysis. After two workshops at Audio Mostly 2021 and IEEE VIS, this 3rd workshop on audio-visual analytics continues building a community of researchers interested in combining visualization and sonification.
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| 2. |
- Assarsson, Ulf, 1972, et al.
(författare)
-
Image-Space Dynamic Transparency for Improved Object Discovery in 3D Environments
- 2006
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We present an image-space algorithm for dynamic transparency with the purpose of supporting object discovery and access in information-rich 3D visualization environments. The algorithm is based on multiple rendering passes and detects instances of object occlusion in the image-space using the fragment shader capabilities of modern programmable graphics hardware, creating alpha maps of opacity gradients around the occluded objects. In essence, the effect is somewhat similar to X-ray vision of a superhero. We have implemented a prototype version of our algorithm with real-time rendering performance using a number of optimizations and speedups on current graphics hardware. To evaluate its use, we have also implemented three different example applications portraying different scenarios, including abstract visualization, virtual walkthrough, and gaming. Preliminary results from an empirical user study comparing our technique to standard viewpoint controls indicate that our technique is superior in regards to object discovery efficiency. These results hold over both completion times as well as correctness of a visual search task.
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| 3. |
- Dancu, Alexandru, 1985, et al.
(författare)
-
Map Navigation Using a Wearable Mid-air Display
- 2015
-
Ingår i: 17th International Conference on Human-Computer Interaction with Mobile Devices and Services, MobileHCI 2015; Copenhagen, Denmark; 24 August-27 August 2015. - New York, NY, USA : ACM. - 9781450336529 ; , s. 71-76
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Konferensbidrag (refereegranskat)abstract
- Advances in display technologies could soon make - wearable mid-air displays -devices that present dynamic images floating in mid-air relative to a mobile user---available.Such devices may enable new input and output modalities compared to current mobile devices, and seamlessly offer information on the go.This paper presents a functional prototype for the purpose of understanding these modalities in more detail, including suitable applications and device placement.We first collected results from an online survey identified map navigation as one of the most desirable applications and suggested placement preferences. Based on these rankings, we built a wearable mid-air display mockup consisting of mobile phone, pico projector, and a holder frame, mountable in two alternative ways: wrist and chest.We then designed an experiment, asking participants to navigate different urban routes using map navigation displayed in mid-air. For map navigation, participants ranked wrist-mount safer than chest-mount. The experiment results validate the use of a wearable mid-air display for map navigation.Based on our online survey and experiment, we offer insights and recommendations for the design of wearable mid-air displays.
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| 4. |
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| 5. |
- Elmqvist, Niklas, 1977
(författare)
-
3D Occlusion Management and Causality Visualization
- 2006
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is split into two parts: one part dealing with the management of occlusion in 3D environments, the other with the visualization of causal relations. Both of these parts fall within the general framework of visualization---the graphical representation of data (abstract or concrete) with the purpose of amplifying cognition---but they do so in different ways.3D occlusion management, on the one hand, is a basic approach to augmenting three-dimensional visualizations with a set of orthogonal techniques for reducing (or even eliminating) the effect of inter-object occlusion in the environment. We present four different such techniques in the thesis, each utilizing a different solution space to achieve the effect: the image space for dynamic transparency, view space for view projection animation, object space for our interactive 3D distortion technique, and temporal space for our approach to 3D navigation guidance. Each technique is orthogonal to the others, and each has been verified empirically through formal user experiments to promote significantly more efficiency and accuracy for users solving representative visual perception task in 3D environments than standard 3D navigation controls such as flying and walking.Causality visualization, on the other hand, is a specific class of visualization techniques designed to make complex chains of causal dependencies, or cause-and-effect relations, visible and understandable. A core information visualization problem, the techniques described in this part of the thesis are examples of growing geometry, a subset of methods based on mapping the time parameter to the size of geometrical primitives such as squares and polygons. Consequently, the techniques are called Growing Squares and Growing Polygons, respectively, and utilize color, texture, and animation to visualize causality from application areas such as distributed systems, social networks, and mathematics. These, too, have been empirically shown to be superior to traditional time-space diagrams for representing causal relations. The CiteWiz system serves as a concrete example of how to apply causality visualization to a real dataset, in this case scientific citation data.
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| 6. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
3DVN: A Mixed Reality Platform for Mobile Navigation Assistance
- 2006
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We present 3DVN, a Mixed Reality platform for navigation assistance in indoor environments. Built on top of a PC-based wearable computer running the Windows operating system, the platform provides a multimodal user interface for navigating in existing physical buildings, including wireless networking, data glove gestural input, voice communication, head-mounted display, and a 3DOF head tracker. Local positioning is performed using a software-only positioning engine making use of WLAN features for accurately pinpointing the mobile device in three dimensions. The 3DVN system has been implemented as a proof-of-concept of a navigation guidance support device for visitors, and has been field-tested with human subjects in the student center of our university. Informal evaluation of subject ratings indicate a strong interest for the new system, both for guests as well as people familiar with the campus and the building.
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| 7. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
3DVN: A Mixed Reality Platform for Mobile Navigation Assistance
- 2007
-
Ingår i: ACM CHI2007 Workshop on Mobile Spatial Interaction. ; , s. 1-4
-
Konferensbidrag (refereegranskat)abstract
- We present 3DVN, a Mixed Reality platform for navigation assistance in indoor environments. Built on top of a PC-based wearable computer running the Windows operating system, the platform provides a multimodal user interface to navigate existing physical buildings, including wireless networking, data glove gestural input, voice communication, head-mounted display, and a 3DOF head tracker. Local positioning is performed using a software-only WLAN-based engine to accurately pinpoint the mobile device in three dimensions. We use this system as a platform for a simple theoretical framework for classifying interaction for mobile navigation assistance. Informal qualitative evaluation of our system seems to conform to predictions derived from our framework and shows the need for a rich set of interaction components for successful mobile navigation.
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| 8. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
3Dwm: A Platform for Research and Development of Three-Dimensional User Interfaces
- 2003
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Although hugely successful, the near-ubiquitous WIMP paradigm dates back to the 1970s and has many shortcomings that could be addressed by harnessing modern computing technology in the user interface. Most importantly, the ready supply of consumer-level hardware-accelerated 3D graphics has opened the way for 3D user interfaces, i.e. interfaces that make direct use of the third dimension. However, there are many challenges to designing applications with such interfaces. In this paper, we present 3Dwm, an object-oriented software platform for the research and development of 3D user interfaces, and discuss how it addresses these challenges. 3Dwm provides a unified 3D abstraction layer that facilitates interoperability between 3D components, combats the inherent complexity of 3D interface programming, provides a reusable toolkit for application building, supports network-aware 3D visualization applications, and may potentially serve as a standardized software platform for many kinds of 3D graphics development.
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| 9. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
A Taxonomy of 3D Occlusion Management for Visualization
- 2008
-
Ingår i: IEEE Transactions on Visualization and Computer Graphics. - 1941-0506 .- 1077-2626. ; 14:5, s. 1095-1109
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Tidskriftsartikel (refereegranskat)abstract
- While an important factor in depth perception, the occlusion effect in 3D environments also has a detrimental impact on tasks involving discovery, access, and spatial relation of objects in a 3D visualization. A number of interactive techniques have been developed in recent years to directly or indirectly deal with this problem using a wide range of different approaches. In this paper, we build on previous work on mapping out the problem space of 3D occlusion by defining a taxonomy of the design space of occlusion management techniques in an effort to formalize a common terminology and theoretical framework for this class of interactions. We classify a total of 50 different techniques for occlusion management using our taxonomy and then go on to analyze the results, deriving a set of five orthogonal design patterns for effective reduction of 3D occlusion. We also discuss the "gaps" in the design space, areas of the taxonomy not yet populated with existing techniques, and use these to suggest future research directions into occlusion management.
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| 10. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
A Taxonomy of 3D Occlusion Management Techniques
- 2006
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- While an important factor in depth perception, the occlusion effect in 3D environments also has a detrimental impact on tasks involving discovery, access, and spatial relation of objects in a 3D visualization. A number of interactive techniques have been developed in recent years to directly or indirectly deal with this problem using a wide range of different approaches. In this paper, we build on previous work on mapping out the problem space of 3D occlusion by defining a taxonomy of the design space of occlusion management techniques in an effort to formalize a common terminology and theoretical framework for this class of interactions. We classify a total of 25 different techniques for occlusion management using our taxonomy and then go on to analyze the results, deriving a set of five orthogonal design patterns for effective reduction of 3D occlusion. Wealso discuss the ``gaps'' in the design space, areas of the taxonomy not yet populated with existing techniques, and use these to suggest future research directions into occlusion management.
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| 11. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
A Taxonomy of 3D Occlusion Management Techniques
- 2007
-
Ingår i: Proceedings of the IEEE Conference on Virtual Reality 2007.
-
Konferensbidrag (refereegranskat)abstract
- While an important factor in depth perception, the occlusion effect in 3D environments also has a detrimental impact on tasks involving discovery, access, and spatial relation of objects in a 3D visualization. A number of interactive techniques have been developed in recent years to directly or indirectly deal with this problem using a wide range of different approaches. In this paper, we build on previous work on mapping out the problem space of 3D occlusion by defining a taxonomy of the design space of occlusion management techniques in an effort to formalize a common terminology and theoretical framework for this class of interactions. We classify a total of 25 different techniques for occlusion management using our taxonomy and then go on to analyze the results, deriving a set of five orthogonal design patterns for effective reduction of 3D occlusion. We also discuss the gaps in the design space, areas of the taxonomy not yet populated with existing techniques, and use these to suggest future research directions into occlusion management.
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| 12. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
Animated Visualization of Causal Relations Through Growing 2D Geometry
- 2004
-
Ingår i: Information Visualization. ; 3:3, s. 154-172
-
Tidskriftsartikel (refereegranskat)abstract
- Causality visualization is an important tool for many scientific domains that involve complex interactions between multiple entities (examples include parallel and distributed systems in computer science). However, traditional visualization techniques such as Hasse diagrams are not well-suited to large system executions, and users often have difficulties answering even basic questions using them, or have to spend inordinate amounts of time to do so. In this paper we present the Growing Squares and Growing Polygons methods, two sibling visualization techniques that were designed to solve this problem by providing efficient 2D causality visualization through the use of color, texture, and animation. Both techniques have abandoned the traditional linear timeline and instead map the time parameter to the size of geometrical primitives representing the processes; in the Growing Squares case, each process is a color-coded square that receives color influences from other process squares as messages reach it; in the Growing Polygons case, each process is instead an $n$-sided polygon consisting of triangular sectors showing color-coded influences from the other processes. We have performed user studies of both techniques, comparing them with Hasse diagrams, and they have been shown to be significantly more efficient than old techniques, both in terms of objective performance as well as the subjective opinion of the test subjects (the Growing Squares technique is, however, only significantly more efficient for small systems).
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| 13. |
- Elmqvist, Niklas, 1977
(författare)
-
BalloonProbe: Reducing Occlusion in 3D using Interactive Space Distortion
- 2005
-
Ingår i: Proceedings of the ACM Symposium on Virtual Reality Software & Technology 2005.
-
Konferensbidrag (refereegranskat)abstract
- Using a 3D virtual environment for information visualization is a promising approach, but can in many cases be plagued by a phenomenon of literally not being able to see the forest for the trees. Some parts of the 3D visualization will inevitably occlude other parts, leading both to loss of efficiency and, more seriously, correctness; users may have to change their viewpoint in a non-trivial way to be able to access hidden objects, and, worse, they may not even discover some of the objects in the visualization due to this inter-object occlusion. In this paper, we present a space distortion interaction technique called the BalloonProbe which, on the users command, inflates a spherical force field that repels objects around the 3D cursor to the surface of the sphere, separating occluding objects from each other. Inflating and deflating the sphere is performed through smooth animation, ghosted traces showing the displacement of each repelled object. Our prototype implementation uses a 3D cursor for positioning as well as for inflating and deflating the force field balloon. Informal testing suggests that the BalloonProbe is a powerful way of giving users interactive control over occlusion in 3D visualizations.
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| 14. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
Causality Visualization Using Animated Growing Polygons
- 2003
-
Ingår i: Proceedings - IEEE Symposium on Information Visualization, INFO VIS. - 1522-404X. - 0780381548 ; , s. 189-196
-
Konferensbidrag (refereegranskat)abstract
- We present Growing Polygons, a novel visualization technique for the graphical representation of causal relations and information flow in a system of interacting processes. Using this method, individual processes are displayed as partitioned polygons with color-coded segments showing dependencies to other processes. The entire visualization is also animated to communicate the dynamic execution of the system to the user. The results from a comparative user study of the method show that the Growing Polygons technique is significantly more efficient than the traditional Hasse diagram visualization for analysis tasks related to deducing information flow in a system for both small and large executions. Furthermore, our findings indicate that the correctness when solving causality tasks is significantly improved using our method. In addition, the subjective ratings of the users rank the method as superior in all regards, including usability, efficiency, and enjoyability.
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| 15. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
CiteWiz: a tool for the visualization of scientific citation networks
- 2007
-
Ingår i: Information Visualization. - 1473-8716 .- 1473-8724. ; 6:3, s. 215-232
-
Tidskriftsartikel (refereegranskat)abstract
- We present CiteWiz, an extensible framework for visualization of scientific citation networks. The system is based on a taxonomy of citation database usage for researchers, and provides a timeline visualization for overviews and an influence visualization for detailed views. The timeline displays the general chronology and importance of authors and articles in a citation database, whereas the influence visualization is implemented using the Growing Polygons technique, suitably modified to the context of browsing citation data. Using the latter technique, hierarchies of articles with potentially very long citation chains can be graphically represented. The visualization is augmented with mechanisms for parent–child visualization and suitable interaction techniques for interacting with the view hierarchy and the individual articles in the dataset. We also provide an interactive concept map for keywords and co-authorship using a basic force-directed graph layout scheme. A formal user study indicates that CiteWiz is significantly more efficient than traditional database interfaces for high-level analysis tasks relating to influence and overviews, and equally efficient for low-level tasks such as finding a paper and correlating bibliographical data.
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| 16. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
CiteWiz: A Tool for the Visualization of Scientific Citation Networks
- 2004
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The management of citation data for scientific articles is part of everyday life for a researcher. In this paper, we present CiteWiz, an extensible framework for visualization of scientific networks. The system is based on a taxonomy of citation database usage for researchers, and uses the Growing Polygons causality visualization technique, suitably modified to the context of citation data. Using this technique, hierarchies of articles with potentially very long citation chains can be graphically represented. The visualization is augmented with mechanisms for parent-child visualization, color assignment, as well as suitable interaction techniques for interacting with the view hierarchy and the individual articles in the dataset. Furthermore, the tool includes a static timeline visualization for overviewing the causality and importance of authors and articles in a citation database. Informal pilot studies with active researchers indicate that CiteWiz is useful for a wide range of scientific activities, and could well become a standard tool in their everyday work.
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| 17. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
DataMeadow: a visual canvas for analysis of large-scale multivariate data
- 2008
-
Ingår i: Information Visualization. - : SAGE Publications. - 1473-8716 .- 1473-8724. ; 7:1, s. 18-33
-
Tidskriftsartikel (refereegranskat)abstract
- Supporting visual analytics of multiple large-scale multidimensional data sets requires a high degree of interactivity and user control beyond the conventional challenges of visualizing such data sets. We present the DataMeadow, a visual canvas providing rich interaction for constructing visual queries using graphical set representations called DataRoses. A DataRose is essentially a starplot of selected columns in a data set displayed as multivariate visualizations with dynamic query sliders integrated into each axis. The purpose of the DataMeadow is to allow users to create advanced visual queries by iteratively selecting and filtering into the multidimensional data. Furthermore, the canvas provides a clear history of the analysis that can be annotated to facilitate dissemination of analytical results to stakeholders. A powerful direct manipulation interface allows for selection, filtering, and creation of sets, subsets, and data dependencies. We have evaluated our system using a qualitative expert review involving two visualization researchers. Results from this review are favorable for the new method.
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| 18. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
DataMeadow: A Visual Canvas for Analysis of Large-Scale Multivariate Data
- 2007
-
Ingår i: Proceedings of the IEEE Symposium on Visual Analytics Science and Technology 2007 (VAST 2007). - 9781424416592 ; , s. 187-194
-
Konferensbidrag (refereegranskat)abstract
- Supporting visual analytics of multiple large-scale multidimensional datasets requires a high degree of interactivity and user control beyond the conventional challenges of visualizing such datasets. We present the DataMeadow, a visual canvas providing rich interaction for constructing visual queries using graphical set representations called DataRoses. A DataRose is essentially a starplot of selected columns in a dataset displayed as multivariate visualizations with dynamic query sliders integrated into each axis. The purpose of the DataMeadow is to allow users to create advanced visual queries by iteratively selecting and filtering into the multidimensional data. Furthermore, the canvas provides a clear history of the analysis that can be annotated to facilitate dissemination of analytical results to outsiders. Towards this end, the DataMeadow has a direct manipulation interface for selection, filtering, and creation of sets, subsets, and data dependencies using both simple and complex mouse gestures. We have evaluated our system using a qualitative expert review involving two researchers working in the area. Results from this review are favorable for our new method.
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| 19. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
Dynamic Transparency for 3D Visualization: Design and Evaluation
- 2009
-
Ingår i: International Journal of Virtual Reality. - 1081-1451. ; 1:8, s. 65-78
-
Tidskriftsartikel (refereegranskat)abstract
- Recent developments in occlusion management for 3D environments often involve the use of dynamic transparency, or “virtual X-ray vision”, to promote target discovery and access in complex 3D worlds. However, there are many different approach- es to achieving this effect and their actual utility for the user has yet to be evaluated. Furthermore, the introduction of semi- transparent surfaces adds additional visual complexity that may actually have a negative impact on task performance. In this paper, we report on an empirical user study investigating these human aspects of dynamic transparency. Our implementation of the technique is an image-space algorithm built using modern programmable shaders to achieve real-time performance and visually pleasing results. Results from the user study indicate that dynamic transparency provides superior performance for perceptual tasks in terms of both efficiency and correctness. Subjective ratings are also firmly in favor of the method.
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| 20. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
Employing Dynamic Transparency for 3D Occlusion Management: Design Issues and Evaluation
- 2007
-
Ingår i: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - 1611-3349 .- 0302-9743. - 9783540747949 ; 4662, s. 532 - 545
-
Konferensbidrag (refereegranskat)abstract
- Recent developments in occlusion management for 3D environments often involve the use of dynamic transparency, or virtual “X-ray vision”, to promote target discovery and access in complex 3D worlds. However, there are many different approaches to achieving this effect and their actual utility for the user has yet to be evaluated. Furthermore, the introduction of semi-transparent surfaces adds additional visual complexity that may actually have a negative impact on task performance. In this paper, we report on an empirical user study comparing dynamic transparency to standard viewpoint controls. Our implementation of the technique is an image-space algorithm built using modern programmable shaders to achieve real-time performance and visually pleasing results. Results from the user study indicate that dynamic transparency is superior for perceptual tasks in terms of both efficiency and correctness.
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| 21. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
Evaluating motion constraints for 3D wayfinding in immersive and desktop virtual environments
- 2008
-
Ingår i: Proceeding of the twenty-sixth annual CHI conference on Human factors in computing systems. - 9781605580111 ; , s. 1769-1778
-
Konferensbidrag (refereegranskat)abstract
- Motion constraints providing guidance for 3D navigation have recently been suggested as a way of offloading some of the cognitive effort of traversing complex 3D environments on a computer. We present findings from an evaluation of the benefits of this practice where users achieved significantly better results in memory recall and performance when given access to such a guidance method. The study was conducted on both standard desktop computers with mouse and keyboard, as well as on an immersive CAVE system. Interestingly, our results also show that the improvements were more dramatic for desktop users than for CAVE users, even outperforming the latter. Furthermore, the study indicates that allowing the users to retain local control over the navigation on the desktop platform helps them in familiarizing themselves with the 3D world.
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| 22. |
- Elmqvist, Niklas, 1977, et al.
(författare)
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Evaluating the Effectiveness of Occlusion Reduction Techniques for 3D Virtual Environments
- 2006
-
Ingår i: Proceedings of the ACM Symposium on Virtual Reality Software & Technology 2006. ; , s. 9-18
-
Konferensbidrag (refereegranskat)abstract
- We present an empirical usability experiment studying the relative strengths and weaknesses of three different occlusion reduction techniques for discovering and accessing objects in information-rich 3D virtual environments. More specifically, the study compares standard 3D navigation, generalized fisheye techniques using object scaling and transparency, and the BalloonProbe interactive 3D space distortion technique. Subjects are asked to complete a number of different tasks, including counting, pattern recognition, and object relation, in different kinds of environments with various properties. The environments include a free-space abstract 3D environment and a virtual 3D walkthrough applicationfor a simple building floor. The study involved 16 subjects and was conducted in a three-sided CAVE environment. Our results confirm the general guideline that each task calls for a specialized interactionno single technique performed best across all tasks and worlds. The results also indicate a clear trade-off between speed and accuracy; simple navigation was the fastest but also most error-prone technique, whereas spherical BalloonProbe proved the most accurate but required longer completion time, making it suitable for applications where mistakes incur a high cost.
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| 23. |
- Elmqvist, Niklas, et al.
(författare)
-
Fluid Interaction for Information Visualization
- 2011
-
Ingår i: Information Visualization. - : SAGE Publications. - 1473-8716 .- 1473-8724. ; 10:4, s. 327-340
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Tidskriftsartikel (refereegranskat)abstract
- Despite typically receiving little emphasis in visualization research, interaction in visualization is the catalyst for the user’s dialogue with the data, and, ultimately, the user’s actual understanding and insight into these data. There are many possible reasons for this skewed balance between the visual and interactive aspects of a visualization. One reason is that interaction is an intangible concept that is difficult to design, quantify, and evaluate. Unlike for visual design, there are few examples that show visualization practitioners and researchers how to design the interaction for a new visualization in the best manner. In this article, we attempt to address this issue by collecting examples of visualizations with ‘best-in-class’ interaction and using them to extract practical design guidelines for future designers and researchers. We call this concept fluid interaction, and we propose an operational definition in terms of the direct manipulation and embodied interaction paradigms, the psychological concept of ‘flow’, and Norman’s gulfs of execution and evaluation.
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| 24. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
Growing Squares: Animated Visualization of Causal Relations
- 2003
-
Ingår i: Proceedings of the ACM 2003 Symposium on Software Visualization (SoftVis 2003), San Diego, 11-13 June 2003. - New York, NY, USA : ACM. - 9781581136425 ; , s. 17-26
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Konferensbidrag (refereegranskat)abstract
- We present a novel information visualization technique for the graphical representation of causal relations, that is based on the metaphor of color pools spreading over time on a piece of paper. Messages between processes in the system affect the colors of their respective pool, making it possible to quickly see the influences each process has received. This technique, called Growing Squares, has been evaluated in a comparative user study and shown to be significantly faster and more efficient for sparse data sets than the traditional Hasse diagram visualization. Growing Squares were also more efficient for large data sets, but not significantly so. Test subjects clearly favored Growing Squares over old methods, naming the new technique easier, more efficient, and much more enjoyable to use.
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| 25. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
Growing Squares: Animated Visualization of Causal Relations
- 2002
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We present a novel information visualization technique for the graphical representation of causal relations, that is based on the metaphor of color pools spreading over time on a piece of paper. Messages between processes in the system affect the colors of their respective pool, making it possible to quickly see the influences each process has received. This technique, called Growing Squares, has been evaluated in a comparative user study and shown to be significantly faster and more efficient for sparse data sets than the traditional Hasse diagram visualization. Growing Squares were also more efficient for large data sets, but not significantly so. Test subjects clearly favored Growing Squares over old methods, naming the new technique easier, more efficient, and much more enjoyable to use.
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| 26. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
On Navigation Guidance for Exploration of 3D Environments
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Navigation in complex and large-scale 3D virtual environments has been shown to be a difficult task, imposing a high cognitive load on the user. In this paper, we present a comprehensive method for assisting users in exploring and understanding such 3D worlds, computing first a complete path through the world used as a basis for exploration and then supporting the rich interactions necessary for navigating and wayfinding in the world. The method consists of two distinct phases: an off-line computation step deriving a grand tour using the world geometry and any semantic target information as input, and an on-line interactive navigation step providing guided exploration and improved spatial perception for the user. The former phase is based on a voxelized version of the geometrical dataset that is used to compute a connectivity graph for use in a TSP-like formulation of the problem. The latter phase takes the output tour from the off-line step as an input for guiding 3D navigation through the environment using a technique we call spring-zooming. A user study indicates a significant efficiency improvement in performing visual search tasks in a complex 3D environment using the technique in comparison to unaided 3D navigation. Furthermore, the results show that the spring-zooming technique strikes a good balance between guidance and interaction, achieving significantly better general recall performance in comparison to a simple tour-following technique allowing for no user control.
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| 27. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
Reducing Occlusion in 3D Environments Through Smooth Camera Projection Animation
- 2005
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Inter-object occlusion is intrinsic to 3D environments and is one of the main problems of using 3D instead of 2D computer graphics for information visualization. In this paper, we examine occlusion in depth, both in a theoretical treatment as well as in an empirical user study. Furthermore, we present an interaction technique for camera projection animation that reduces inter-object occlusion in 3D environments without modifying the geometrical properties of the objects themselves. The technique provides smooth on-demand animation between parallel and perspective projection modes as well as online manipulation of view parameters, allowing the user to quickly and easily adapt the view to avoid inter-object occlusion. This also simplifies object access by supporting 3D picking in ortographic mode. Our user study indicate that the technique significantly improves object discovery over normal perspective views. By treating the 3D objects in the environment as immutable entities, the technique is non-invasive and can seamlessly be integrated into any kind of 3D visualization.
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| 28. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
Tour Generation for Exploration of 3D Virtual Environments
- 2007
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Ingår i: the Proceedings of the ACM Symposium on Virtual Reality Software and Technology 2007 (VRST 2007), ACM press. - 9781595938633 ; , s. 207-210
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Konferensbidrag (refereegranskat)abstract
- Navigation in complex and large-scale 3D virtual environments hasbeen shown to be a difficult task, imposing a high cognitive loadon the user. In this paper, we present a comprehensive method forassisting users in exploring and understanding such 3D worlds. Themethod consists of two distinct phases: an off-line computation stepderiving a grand tour using the world geometry and any semantictarget information as input, and an on-line interactive navigationstep providing guided exploration and improved spatial perceptionfor the user. The former phase is based on a voxelized version ofthe geometrical dataset that is used to compute a connectivity graphfor use in a TSP-like formulation of the problem. The latter phasetakes the output tour from the off-line step as input for guiding 3Dnavigation through the environment.
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| 29. |
- Elmqvist, Niklas, 1977, et al.
(författare)
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TrustNeighborhoods: Visualizing Trust in Distributed File Sharing Systems
- 2007
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Ingår i: Proceedings of Eurographics/ IEEE-VGTC Symposium on Visualization 2007. ; , s. 107-114
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Konferensbidrag (refereegranskat)abstract
- We present TrustNeighborhoods, a security trust visualization for situational awareness on the Internetaimed at novice and intermediate users of a distributed file sharing system. The TrustNeighborhoodstechnique uses the metaphor of a multi-layered city or fortress to intuitively represent trust as a simplegeographic relation. The visualization uses a radial space-filling layout; there is a 2D mode for editingand configuration, as well as a 3D mode for exploration and overview. In addition, the 3D modesupports a simple animated “fly-to” command that is intended to show the user the context and trustof a particular document by zooming in on the document and its immediate neighborhood in the 3Dcity. The visualization is intended for integration into an existing desktop environment, connectingto the distributed file sharing mechanisms of the environment and non-obtrusively displaying a 3Dorientation animation in the background for any file being accessed over the network. A formal userstudy shows that the technique supports significantly higher trust assignment accuracy than manualtrust assignment at the cost of only a minor time investment.
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| 30. |
- Elmqvist, Niklas, 1977, et al.
(författare)
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TrustNeighborhoods: Visualizing Trust in Distributed File Sharing Systems
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We present TrustNeighborhoods, a security trust visualization aimed at novice and intermediate users of a distributed file sharing system. Building on the idea of ``circles of relationships'' as a model for computer usage proposed by Shneiderman, the TrustNeighborhoods technique uses the metaphor of a city to intuitively represent trust as a simple geographic relation, starting from the safe confines of one's own home to our own street, neighborhood, and the whole city itself. This metaphor gives users an easy way to relate to the trust of a document assigned by themselves as well as other users in the system. The visualization uses a radial space-filling layout; there is a 2D mode for editing and configuration, as well as a 3D mode for exploration and overview. In addition, the 3D mode supports a simple animated ``fly to'' command which is intended to show the user the context and trust of a particular document by zooming in on the document and its immediate neighborhood in the 3D city. The visualization is intended for integration into an existing desktop environment, connecting to the distributed file sharing mechanisms of the environment and non-obtrusively displaying a 3D orientation animation in the background for any file being accessed over the network. Informal testing indicates that the technique is a useful and intuitive way of visualizing trust in distributed file sharing networks.
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| 31. |
- Elmqvist, Niklas, 1977, et al.
(författare)
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View-projection animation for 3D occlusion management
- 2007
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Ingår i: Computers and Graphics. - : Elsevier BV. - 0097-8493. ; 31:6, s. 864-876
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Tidskriftsartikel (refereegranskat)abstract
- Inter-object occlusion is inherent to 3D environments and is one of the challenges of using 3D instead of 2D computer graphics for visualization. Based on an analysis of this effect, we present an interaction technique for view-projection animation that reduces inter-object occlusion in 3D environments without modifying the geometrical properties of the objects themselves. The technique allows for smooth on-demand animation between parallel and perspective projection modes as well as online manipulation of view parameters, enabling the user to quickly and easily adapt the view to reduce occlusion. A user study indicates that the technique provides many of the occlusion reduction benefits of traditional camera movement, but without the need to actually change the viewpoint. We have also implemented a prototype of the technique in the Blender 3D modeler.
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| 32. |
- Elmqvist, Niklas, 1977, et al.
(författare)
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View Projection Animation for Occlusion Reduction
- 2006
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Ingår i: Proceedings of the ACM Conference on Advanced Visual Interfaces 2006. ; , s. 471-475
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Konferensbidrag (refereegranskat)abstract
- Inter-object occlusion is inherent to 3D environments and is one of the challenges of using 3D instead of 2D computer graphics for information visualization. In this paper, we examine this occlusion problem by building a theoretical framework of its causes and components. As a result of this analysis, we present an interaction technique for view projection animation that reduces inter-object occlusion in 3D environments without modifying the geometrical properties of the objects themselves. The technique provides smooth on-demand animation between parallel and perspective projection modes as well as online manipulation of view parameters, allowing the user to quickly and easily adapt the view to avoid occlusion. A user study indicates that the technique significantly improves object discovery over normal perspective views. We have also implemented a prototype of the technique in the Blender 3D modeller.
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| 33. |
- Elmqvist, Niklas, 1977
(författare)
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Visualization of Causal Relations
- 2004
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The notion of cause and effect is pervasive in human thinking and plays a significant role in our perception of time. Software systems, in particular parallel and distributed ones, are permeated by this causality, and the human mind is especially well-suited to detect instances of this concept. Unfortunately, real-world systems of causally related events are often too large and complex to be comprehended unaided. In this thesis, we explore ways of using information visualization to help humans perceive these complex systems of causal relations, not only for software systems, but also for more general application areas.The Growing Squares visualization technique uses a combination of color, texture, and animation to present a sequence of related events in a distributed system. User studies show that this technique is significantly more effective for solving problems related to causality in distributed systems than traditional Hasse diagrams for small data sets, and more effective (though not significantly so) for large data sets.The Growing Polygons visualization technique was designed to address some of the weaknesses of the Growing Squares technique, and presents the interacting processes in a system as color-coded polygons with sectors indicating the influences and information propagation in the system. User studies show that this technique is significantly more effective than Hasse diagrams for all data sets, regardless of size.Finally, we have conducted a case study of causality visualization in the context of scientific citation networks, creating a bibliographic visualization tool called CiteWiz. The tool contains a modified Growing Polygons visualization, suitably adapted to citation networks with linear time windows and process hierarchies, as well as a new static timeline visualization that maps the citation count and publication date of an article or author to its size and position on the timeline, respectively.
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| 34. |
- Isenberg, Petra, et al.
(författare)
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Collaborative Visualization: Definition, Challenges, and Research Agenda
- 2011
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Ingår i: Information Visualization. - : SAGE Publications. - 1473-8716 .- 1473-8724. ; 10:4, s. 310-326
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Tidskriftsartikel (refereegranskat)abstract
- The conflux of two growing areas of technology – collaboration and visualization – into a new research direction, collaborative visualization, provides new research challenges. Technology now allows us to easily connect and collaborate with one another – in settings as diverse as over networked computers, across mobile devices, or using shared displays such as interactive walls and tabletop surfaces. Digital information is now regularly accessed by multiple people in order to share information, to view it together, to analyze it, or to form decisions. Visualizations are used to deal more effectively with large amounts of information while interactive visualizations allow users to explore the underlying data. While researchers face many challenges in collaboration and in visualization, the emergence of collaborative visualization poses additional challenges, but it is also an exciting opportunity to reach new audiences and applications for visualization tools and techniques.The purpose of this article is (1) to provide a definition, clear scope, and overview of the evolving field of collaborative visualization, (2) to help pinpoint the unique focus of collaborative visualization with its specific aspects, challenges, and requirements within the intersection of general computer-supported cooperative work and visualization research, and (3) to draw attention to important future research questions to be addressed by the community. We conclude by discussing a research agenda for future work on collaborative visualization and urge for a new generation of visualization tools that are designed with collaboration in mind from their very inception.
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| 35. |
- Kronander, Håkan, et al.
(författare)
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Analysis of ST/HR hysteresis improves long-term prognostic value of exercise ECG test.
- 2011
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Ingår i: International Journal of Cardiology. - : Elsevier BV. - 0167-5273 .- 1874-1754. ; 148:1, s. 64-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: ST/HR hysteresis is one of the better diagnostic exercise ECG variables for coronary artery disease. This study evaluates the long-term prognostic value of ST/HR hysteresis in predicting acute myocardial infarction (AMI) and all-cause mortality in men and women. METHODS: The study population consisted of 8317 patients who had undergone routine exercise test on bicycle ergometer at one Swedish centre. Information on AMI and all-cause mortality was obtained from national Swedish registers covering a mean follow-up period of 9.5 years. RESULTS: The adjusted hazard ratio for AMI at a diagnostic cut point of ≤-20 µV for ST/HR hysteresis was 1.88 (95% CI, 1.62-2.17) in men and 2.31 (95% CI, 1.83-2.91) in women. For all-cause death the adjusted hazard ratio was 1.72 (95% CI, 1.52-1.96) in men and 1.90 (95% CI, 1.57-2.29) in women. The corresponding hazard ratios for ST-segment depression with horizontal or down-sloping ST-segment, ST-segment depression, ST/HR index, and ST/HR slope were lower. For comparison, the adjusted hazard ratio for AMI using maximal workload in percent of predicted was 2.02 (95% CI, 1.77-2.32) in men and 2.14 (95% CI, 1.71-2.67) in women. Area under the ROC curves for prediction of AMI was significantly larger using ST/HR hysteresis than using any of three other evaluated ECG indicators. CONCLUSIONS: ST/HR hysteresis appears to improve the prognostic ability of an exercise ECG test for AMI and all-cause mortality in a long-term perspective compared to conventional ST-segment and ST/HR indicators in both genders and clearly more markedly in women.
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| 36. |
- Sandberg, Samuel, et al.
(författare)
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Using 3D Audio Guidance to Locate Indoor Static Objects
- 2006
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Ingår i: 50th Annual Meeting of the Human Factors and Ergonomics Society, HFES 2006; San Francisco, CA; United States; 16 October 2006 through 20 October 2006. - 1071-1813. - 9780945289296 ; , s. 1581-1584
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Konferensbidrag (refereegranskat)abstract
- Is 3D audio an interesting technology for displaying navigational information in an indoor environment? This study found no significant differences between map- and 3D audio navigation. The user tasks tested involved finding objects in a real office environment. In order to conduct the study, a custom-made 3D audio system was built based on a public-domain HRTF-library to playback 3D sound beacons through a pair of earphones. Our results indicate that 3D audio is indeed a qualified candidate for navigation systems, and may be especially suitable for environments or individuals where vision is obstructed, insufficient, or unavailable. The study also suggests that special cues should be added to the pure spatial information to emphasize important information.
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| 37. |
- Wybrow, Michael, et al.
(författare)
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Interaction in the visualization of multivariate networks
- 2014
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Ingår i: Towards Multivariate Network Visualization. - Cham : Springer. - 9783319067926 ; , s. 97-125
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Konferensbidrag (refereegranskat)abstract
- The overall aim of visualization is to obtain insight into large amounts of data. Detection of patterns as well as outliers are typical examples. For networks, such patterns can be number and position of cliques; for multivariate data this can be the correlation between attributes. The major challenge of multivariate network visualization is to understand the interplay between properties of the network and its associated data, for instance to see if the formation of cliques can be understood from attributes of nodes.
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