Visualization and Virtual Reality Research Group Meetings

Time/Date	Location	Who	Event
Winter, 2007
28/02/08 14.30	6.08	Roy Ruddle, Nadia Boukhelifa	Research Group Meeting Memory for my life's travels: - Usage scenarios (why store this information?) - Narratives (to link memories together; time, person, place, topic ...) - How to present, filter, organise, cue ... (Slides - PPT) Visualizing clusters in spatio-temporal data and images How to combine hierarchical structures with spatio-temporal data and images in a way that is visually informative. What visualization methods would be useful to visualize trees of features (e.g. features describing clusters in a video sequence) on the image itself (or the video sequence)? (Slides - PPT)
21/02/08 14.30	6.08	Jason Wood, Katarzyna Boronska	Research Group Meeting Visualizing Air Quality Data The UK collects air quality data consisting of a range of chemical species (ozone, CO2, NO etc.) at a selection of monitoring sites (Leeds City Centre, Ladybower Reservoir etc.) delivered as hourly averages. We wish to use this data to motivate the use of a stateful web based visualization service. What would be an interesting set of visualization methods that would benefit from repeated interactions ? Perfectionist's issues with simple 2D geometries Simulations of pattern-forming systems often produce a large number of simple 2D fields. 3D-oriented tools do not seem adapted to efficiently process such data sets. (Slides - ODP)
07/02/08 15.00	Active Learning Lab (9.30a)	Prof. John Davies BAE Systems Insyte	Research Group Meeting Use of computing in large distributed military systems Computing is the major component of all military systems. From real-time array processing that drives sensors, through complex algorithms that enable recognition, through picture compilation and visualisation, recognition, threat analysis and assignment, and networking across all the units engaged in the operation, computing plays a vital role that enables timely, co-ordinated and successful operations. However, as well as the technology; the production, inter-operation and maintenance of such systems present major challenges. These include the use of Architecture Frameworks, major systems integration programmes, issues of productisation, and development and maintenance issues for large programmes and systems produced by large teams across multiple sites and with many stakeholders. This seminar will discuss some of the systems and challenges and how they are being addressed.
31/01/08 16.00	6.08	Darren Treanor LIMM - Faculty of Medicine and Health, University of Leeds	Research Group Meeting An evaluation of virtual slides This seminar will describe the findings from an evaluation of virtual slides that has been conducted with trainee and consultant histopathologists.
29/01/08 14.00	9.30a	Dr John Maxfield, Technical Director and Founder, Icona Solutions Limited	Research Group Meeting From VITAL Proof of Concept to aesthetica: Product Evolution and Technical Challenges VITAL (Visualising the Impact of Tolerance Analysis) was an EPSRC funded research project undertaken within the School of Computing from 1997-2001 in partnership with industrial collaborators from the Automotive Industry, including Jaguar, Rover Group and Magna. With the financial backing of the White Rose Seedcorn Fund, a University Spin-of-Company, Icona Solutions Limited, was formed in 2002 for the commercial exploitation of the results of the VITAL project. Icona's main product, aesthetica, has evolved directly from the original proof of concept system developed within the VITAL project and is now used by many of the world's largest automotive manufacturers and suppliers including General Motors, Chrysler, Nissan, VW, Porsche, Bentley, Hyundai, Renault, EDAG, and PATAC. In this presentation I will review the evolution of the aesthetica product and the technical challenges that were faced in developing a commercial software product from the original proof of concept system. Notes/Links John was a researcher in the School of Computing from 1992-2002. He started as one of the three initial Keyworth Scholars in the Keyworth Institute of Manufacturing and Information System Engineering (which was then directed by Professor Alan de Pennington). John's PhD topic was "A Distributed Virtual Environment for Concurrent Engineering". It was based upon the PhD of Mingxian Fa who undertook the relevant basic research on 3D interactive constraint-based solid modelling in the School of Computing from 1989 t0 1993. John subsequently became an SGI Fellow (1995-1997) and focused on identifying exploitable engineering applications for virtual environments which used the results from his PhD. During this period he was also responsible for establishing the School's Virtual Environment Laboratories funded by the Informatics Institute. The equipment included a flat bed Holobench for 3D interactions in a virtual environment. This research culminated in the VITAL project and spin-off company Icona Solutions Limited described in John's abstract.
24/01/08 14.00	Staff Room	Natasa Milic-Frayling Integrated Systems Microsoft Research , Cambridge	Research Group Meeting Web Site Structure Analysis Web browsers provide support for browsing and re-visiting sites on the Web, including Back and Forward buttons, History, Favourites, and auto-complete for URL typing. These features complement navigation menus, filters, site search and other means for accessing content that are incorporated in the Web site design. While the general browsing behaviour has been studied extensively over the years, less attention has been given to the structure of individual Web sites and their characteristics. In this presentation we introduce Link Structure Graphs (LSG), a new technique for representing and studying the hyperlink structure of Web sites. We illustrate how LSG can be used to partition a site into coherent organizational units referred to as sub-sites. The LSG approach was motivated and evaluated through several user studies. The studies informed on the basic LSG concepts and assessed the effectiveness of LSG representation for identifying entry pages of sub-sites. We present relevant aspects of the user studies and discuss possible applications of the sub-site discovery research. This research is conducted at Microsoft Research Lab in Cambridge by a team of researchers: Eduarda Mendes Rodrigues, Blaz Fortuna, Gavin Smyth, and Natasa Milic-Frayling. Notes/Links Slides - PDF (900k)
17/01/08	Newcastle	Ken Brodlie	VizNet NE Region Visualization Seminar
13/12/07 16.00	6.08	Melvin Hoare Astrophysics Group School of Physics and Astronomy, University of Leeds	Research Group Meeting Surveying our Galaxy I will describe the types of astronomical data being generated by the current new generation of surveys of our Milky Way galaxy and the questions that these data can address. The challenges and opportunities afforded by the large volumes and varied nature of the datasets will be highlighted. Notes/Links The theme for the 2008 IEEE Visualization Design Contest is Multifield 3D Scalar Data. The subject is a galaxy cluster simulation data set submitted by Mike Norman and Robert Harkness.
06/12/07 16.00	6.08	Zhesi He University of York	Research Group Meeting Visualisation and Navigation of High-dimensional Bioinformatics Data The talk will discuss the use of interactive visualisation techniques and various multivariate data analysis methods and development of an interactive visualisation based tool for bioinformatics researches. After a survey on existing methods and tools for various multivariate data analysis studies, we believe that visualisation and interaction approaches facilitate rich information gathering and thus provide better understanding in data exploration. To test applicability of our design, a demonstration tool Vitamin-B (Visual, Interactive Tool for Analysing and MINing Bioinformatics data) was developed and a formal user-based evaluation was performed on selective case studies. Based on encouraging results from the performance and usability evaluations, we conclude that our system has proven that the benefit of interactive visualisation particularly in terms of linking, undo and system integration functionality that makes iterative analysis and drill down operations much easier and quicker to perform. Briefly, we identify future extensions of this project. It is our hope that our prototype will evolve into a system in real use for bioinformatics researchers.
Autumn, 2007
29/11/07 16.00	6.08	Saira Pathan	Research Group Meeting Visualization as a Tool for Neurosurgery Visualization is all about gaining insight and understanding. The roles of visualization in medicine are manifold. First, visualization allows an insight to complex anatomy. Second, it provides assistance to medical professionals at different levels of treatment. And finally, it is used as a teaching and training tool for medical students and trainees. My research focus is to use visualization as a training tool for neurosurgery particularly brain tumour biopsy. In this talk, I will present the work done so far and discuss my crazy ideas.
21/11/07 15.30	6.01 6.02 6.08	(Roy Ruddle)	VVR Open House Details to follow.
15/11/07 16.00	6.08	Dave Harrison	Research Group Meeting Using Scene Graphs for Creating 3D Scenes A scene graph is a representation of a graphics model as an acyclic directed graph of heterogeneous nodes of geometries, properties and transformations, allowing common properties of entire sub-graphs to be grouped in parent nodes. A scene graph is a retained mode graphics API in that the graph persists in memory between frames which allows for optimisations that are not available to the less organised stream of graphics primitives generated by underlying immediate mode API's, such as OpenGL or DirectX. Several mature open source scene graph libraries exist that offer a number of optimisations and facilities to reduce the burden on the programmer and graphics pipeline in creating complex 3D scenes. We will discuss the development of a scene using a simple in house scene graph implementation, then move on to some of the advanced features commonly provided by fully fledged scene graph libraries. Slides - TBZ
08/11/07 16.00	6.08	David Duke, Saira Pathan	Research Group Meeting Report on from IEEE Visualization 2007 Conference A group of us recently attended the IEEE Visualization Conference in Sacramento. This is the major international visualization workshops and the current edition hosted as well a two day Conference on Information Visualization and a Symposium on Visual Analytics. In the session they will attempt to summarize the highlights.
25/10/07 16.00	6.08	Rita Borgo, David Duke	Research Group Meeting "Though this be madness, yet there is method in it": The Importance Of Mathematical Concepts Beneath Contemporary Visualization. Visualization occupies an important role in the pursuit of knowledge as the understanding of real world phenomena. However, behind the image are mathematical models of the world and its representation. At a time when questions about the very core of the discipline, e.g. the relationship between information and scientific visualization, are being raised almost annually within the conference, it seems particular germane to stand back and review what is ultimately what could be the most abstract and neutral picture of visualization itself - the mathematics world which ties together the notion of data and transformation. The panel will involve lively discussion and debate on the kinds of mathematics applicable to visualization and the means by which maths is brought into the discipline. After summarizing the 'case for the defence', members of the panel will be cross-examined by the audience on whether their own work is the madness of genius, or the product of mathematical methods. The deeper question, however, is whether a mathematical civilization beats at the heart of the visualization community. Notes/Links IEEE Visualization Conference 2007, Panel Session
18/10/07 16.00	6.08	Hamish Carr School of Computer Science & Informatics, University College Dublin	Research Group Meeting Topological Quantitation for Medical Problems (based on collaborations with Linkoping, UCD and UC Davis colleagues) Where scientific and engineering visualizations frequently focus on qualitative results - i.e. understanding a system, medical applications frequently require quantitative results that can be recorded for future reference and comparison. Quantitative results, however, often require a preliminary qualitative stage - segmentation. We will show how quantitative information can be integrated with the qualitative segmentation by using topology to link the two stages.
12/10/07 14.00	6.08	Hamish Carr School of Computer Science & Informatics, University College Dublin	AG Seminar (Manchester University) (No) More Marching Cubes Isosurfaces, one of the most fundamental volumetric visualization tools, are commonly rendered using the well-known Marching Cubes cases that approximate contours of trilinearly-interpolated scalar fields. While a complete set of cases has recently been published by Nielson, the formal proof that these cases are the only ones possible and that they are topologically correct is difficult to follow. We present a more straightforward proof of the correctness and completeness of these cases based on a variation of the Dividing Cubes algorithm. Since this proof is based on topological arguments and a divide-and- conquer approach, this also sets the stage for developing tessellation cases for higher-order interpolants and for the quadrilinear interpolant in four dimensions. We also demonstrate that, apart from degenerate cases, Nielson's cases are in fact subsets of two basic configurations of the trilinear interpolant.
11/10/07 16.00	6.08	Benjamin Blundell	Research Group Meeting Visualising Change in Semantic Graphs Details to follow
Summer, 2007
21/06/07 15.30	6.08	Nadia Boukhelifa	Research Group Meeting The Uncertain Reality Of Underground Assests Visualization may be a potent looking-glass for peering into both physical and abstract worlds, but our view is always distorted by inaccuracies in measurements, incompleteness of knowledge, and ambiguities in interpretation. To the visualizer, uncertainty is a particular problem. Depiction depends on the placement of marks on paper or screen, and the placement of such a mark can, implicitly, convey confidence that this feature is in this place rather than another, or even that the existence of the feature is accepted and agreed. In this paper, we use the term uncertainty visualization to refer to the problem of acquiring, modelling and representing data while accounting explicitly for the uncertainties that encompass it. We provide an overview of this growing area, and discuss methods of systematically incorporating knowledge of uncertainty in a geovisualization application. We report on ongoing research in a major industrial application to visualize buried assets while reflecting the uncertainty of our knowledge.
07/06/07 15.30	6.08	Rodolfo Allendes Osorio	Research Group Meeting Developments in uncertainty visualisation Though there have been efforts to include different types of uncertainty into visualisation, these have not focused in the complete integration of uncertainty with the traditional visualisation pipeline. In my presentation, I will review the approach I have been following to manage uncertainty throughout the visualisation process and the results I have obtained so far.
31/05/07 15.30	6.08	Casper Engelen	Research Group Meeting Website Visualization How to visualize the structure of a large website?" is the main question I tried to answer in the last couple of months. This talk will be about my approach to this task, what sort of problems occured and the results achieved so far.
23/05/07 16.00	6.08	Jeremy Walton, NAG Ltd, Oxford.	Research Group Meeting Principles Of Visualization Design: The Good, The Bad and The Ugly Using visualization packages to turn numerical data into pictures can lead to better understanding, but only if the image is a good representation of the data. So what makes one visualization better than another? Although hard and fast rules probably can't be established for all circumstances, the consideration of several examples (good, bad and ugly) might lead to some general principles that could be applied when designing a visualization. This talk will attempt to elucidate them.
10/05/07 15.30	6.08	Hamish Carr School of Computer Science & Informatics, University College Dublin	Research Group Meeting Topology-Controlled Volume Rendering Abstract-Topology provides a foundation for the development of mathematically sound tools for processing and exploration of scalar fields. Existing topology-based methods can be used to identify interesting features in volumetric data sets, to find seed sets for accelerated isosurface extraction, or to treat individual connected components as distinct entities for isosurfacing or interval volume rendering. We describe a framework for direct volume rendering based on segmenting a volume into regions of equivalent contour topology, applying separate transfer functions to each region. Each region corresponds to a branch of a hierarchical contour tree decomposition, and a separate transfer function can be defined for it. Notes/Links "Topology-Controlled Volume Rendering" GH Weber, SE Dillard, H Carr, V Pascucci, B Hamann IEEE Transactions on Visualization and Computer Graphics, March/April 2007 (Vol. 13, No. 2) pp. 330-341
03/05/07 15.30	6.08	Chris Rooney Ken Brodlie	Research Group Meeting 1. Interaction with High Resolution Displays - The Story so Far My talk will be derived from the work I have been done so far this year. I will focus on an analysis on current classifications of interaction techniques, and how I can build on these to create a new taxonomy. They'll be a group discussion on a potential new taxonomy, so bring your thinking caps! 2. A Visualization Timeline Rae Earnshaw (Univ of Bradford) is guest editor of a special issue of IEEE CGA on 'Discovering the Unexpected' (which will cover Visual Analytics) and is considering including in his foreword a timeline for visualization.
27/04/07 14.00	6.08	Robert S Laramee Department of Computer Science, Swansea University	Research Group Seminar The Search for Meaningful Flow Swirl and tumble motion are two important, common fluid flow patterns from computational fluid dynamics (CFD) simulations typical of automotive engine simulation. We study and visualize swirl and tumble flow using several advanced flow visualization techniques: direct, geometric, texture-based, and feature-based. When illustrating these methods, we describe the relative strengths and weaknesses of each approach across multiple spatio-temporal domains typical of an engineer's analysis. The result is the most comprehensive, systematic search for swirl and tumble motion ever performed. Based on this investigation we offer perspectives on where and when these techniques are best applied in order to visualize the behavior of swirl and tumble motion. Notes/Links http://www.vrvis.at/scivis/laramee/MotionExtracted/
26/04/07 15.30	6.08	Nurul Mohd Noor	Research Group Meeting Visualization Notations, Models and Taxonomies Visualization taxonomies are an important means of imposing some structure on a rather diverse field. In this talk, I will present a fresh look of visualization reference model as an evolution of previous models and suggest a new style of notation called Domino Notation. This work may help in develop a visualization taxonomies and contribution to research on ontology. The aim of this research is to describe visualization in a clear and precise way than it is possible at present. This will have benefits in long term archiving of visualizations so they can be recreated long after the software that generated them has expired and also in applications such as asynchronous collaborative visualization where a precise description is needed in order to exchange description between collaborators. Comments and feedback are most welcome.
25/04/07 13.00	Roger Stevens Building LT1 (ground floor)	John S. Hughes Sony Pictures Visual Effects, Hollywood	Talk on CG in Film Industry An Insider's Look at Hollywood Special FX John was in Leeds for 10 years as undergrad, PhD student and Postdoc Research Fellow, before moving to Industry, and ending up as Visual Effects developer for films like Harry Potter, and Spiderman. John is visiting Leeds, and offered to talk about his work. Notes/Links http://www.johnshughes.com/
19/04/07 15.30	6.08	Roy Ruddle	Research Group Meeting Report on IEEE Virtual Reality Conference 2007, Charlotte, USA I'll report on this year's IEEE Virtual Reality conference 2007 in Charlotte, USA, and ask you about your mental representation of a website (come armed with pen + paper).
Spring, 2007
08/03/07 15.30	6.08	Ken Brodlie	VizNet NE Region Visualization Seminar Temporary Venue Details
22/02/07 15.30	6.08	Tim Hattrell School of Mechanical Engineering, University of Leeds	Research Group Meeting Surface Smoothing and Curvature Tim is a Research Fellow in the Combustion Group. He will explain to us the background to his research in premixed turbulent combustion. They have obtained 3D flame volume information by scanning a laser sheet through the flame, and wish to display the flame surface and importantly make calculations such as surface curvature. Marching cubes does not give the results he wants, so the purpose of the informal meeting is to discuss approaches to smoothing isosurfaces so as to enable such calculations.
15/02/07 15.30	6.08	Trevor Dodds	Research Group Meeting Collaborative Interaction in Virtual Environments - Mobile Group Dynamics Previously I have presented to the group a system prototype for evaluating group dynamics within a Collaborative Virtual Environment (CVE), using the context of urban planning. Group dynamics are often studied within a socially driven context in real life, and clearly CVEs can create a visually realistic imitation of the real world to draw on existing social conventions. However, even since early days of VE research, it has been highlighted that "new ways of thinking...must be adopted if VR is to fulfill its potential" (Slater et al. 1994), "CVEs...do not necessarily need to reflect or embody the characteristics of conventional environments to enable them to support particular forms of activity or interaction" (Fraser et al. 2000), "This is the trap VR often falls into; VR tries to imitate reality..." (Pekkola, 2002). Last term I ran two experiments, one of which evaluated Mobile Group Dynamics (MGDs) within the urban planning review system. My talk will look at how groups are conventionally implemented in CVEs, and what functionality I have added to support better collaboration by removing real world constraints and providing support for "mobile" groups working in a large-scale space. Whilst allowance is made for "manual" group work and real world conventions, the MGDs facilitated are designed specifically for and are directly applicable to the virtual world. I will present a summary of the experiment results and welcome any comments/feedback.
08/02/07 15.30	6.08	Tim Wright School of Earth and Environment, University of Leeds	Research Group Meeting Earth-shattering proof of continents on the move (extract from the Reporter 29 January 2007) Africa is being torn apart. And as Ethiopia's rift valley grows slowly wider, an international team of scientists is taking a unique opportunity to plot the progress of continents on the move. The 28-strong team is led by University of Leeds geophysicist Dr Tim Wright, who has secured a 2.5 million grant from the Natural Environment Research Council (NERC) to study the seismic events taking place in the remote Afar desert of Northern Ethiopia. His team, which includes experts from Oxford, Cambridge, Bristol and Edinburgh universities, as well as international researchers from the US, New Zealand, France and Ethiopia, will also use GPS, seismometers, and other geophysical and geochemical techniques to determine the properties of rock and magma below the surface, and to monitor the crust's movement. They will use the data to create a 3D computer model of how magma moves through the Earth's crust to make and break continents.
01/02/07 15.30	6.08	Matthew Birtwisle	Research Group Meeting A 6-DOF Gravity Compensation Scheme for a Phantom Premium Using a Neural Network Current uses of haptic hardware such as the Phantom Premium 6DOF for surgical simulators lack the desired interface transparency and could cause artefacts in the training regime of a student training on a simulator. We address this problem using a neural network to interpolate between empirically discovered data points to generalise over the entire workspace; providing the necessary force/torque vector to send to the Phantom to counteract gravitional forces. A 3DOF gravity simulator is produced, along with an initial 6DOF simulator.
25/01/07 15.30	6.08	Rita Borgo	Research Group Meeting Creating The Motion Illusion The talk will cover a paper from Freeman, Adelson and Heeger entitled "Motion Without Movement"[1]. They describe a method for assigning perceptual motion to objects that remain in fixed positions, by applying local filters and continuously varying their phase. This technique is used to create continuous display of instantaneous motion at a relatively low cost. The aim is to gather opinions and ideas about feasibility of this kind of approach for creating vector fields animation. Notes/Links [1] Freeman, W.T., Adelson, E.H and Heeger D.J. "Motion Without Movement", ACM Computer Graphics, vol. 25, no. 4, (SIGGRAPH 91), pp. 27--30 Slides - ZIP (8Mb)
12/01/07 13.00	Active Learning Lab.	Ken Brodlie	Envisioning Information 2007 Conference Students of the Envisioning Information module within the School of Computing MSc programmes will be presenting their research works developed as part of the module assignements. Presentation will be in the form of an internal Conference, full Conference programme available at Envisioning Information 2007 Conference
Winter, 2006
14/12/06 15.30	VVR Christmas Lunch.
07/12/06 15.30	6.08	Chris Goodyer	Research Group Meeting What Do Oxford Want? What Do Oxford Want? The Integrative Biology project is a multi-million pound multi-site project looking a what causes heart failure and how cancer tumours develop and grow. Together these diseases account for about 60% of UK deaths. The project brings together numerical modellers, computer scientists and heart and cancer specialists. As part of the visualisation strand we have been asked to look at providing "cool visualisations" of some physiological heart data from a group in Oxford. In particular how to show two very high resolution datasets of the same heart collected in different ways. In this talk I shall present the work done so far and be looking for ideas as to what the next stages should be.
30/11/06 15.30	6.08	Nadia Boukhelifa	Research Group Meeting Perceptually-motivated visualizations - preattentive processing and visualization design This talk is based on an ACM paper by Healey et al.[1] and online material on perception in visualization also by Healey [2]. The articles argue for using perception research to assist in the design of visualization tools. In particular, they use findings from preattentive processing research to design visualization applications which require rapid detection of data groups and boundaries, target detection and estimation. I will briefly describe some of the theories behind preattentive processing and move on to talk about example visualization applications that implement such theories. In theory, utilising preattentive processing in visualization design is a powerful idea, but in practice, can this scale to non-trivial visualization problems? Notes/Links [1] Healey,C.G., Brooth,K.S., and Enns,J.T. "Visualizing real-time multivariate data using preattentive processing", ACM Transactions on Modeling and Computer Simulation 5,3, (1995), 190-221.] [2] Healey Lecture Notes
22/11/06 Afternoon	Various	(Roy Ruddle)	VVR Open House Details to follow.
16/11/06 15.00	6.08	Rita Borgo	Research Group Meeting Multi-cultural visualization: How functional programming can enrich visualization (and vice versa) In this talk we present recent advances in the design and implementation of pure functional programming languages that, significantly, contain important insights into questions raised by the recent NIH/NSF report on Visualization Challenges. We argue and demonstrate that modern functional languages can cope with some of the issues raised by the report.
09/11/06 15.30	6.08	David Duke	Research Group Meeting Report from IEEE Visualization 2006 Conference A group of us recently attended the IEEE Visualization Conference in Baltimore. This is the major international visualization workshops and the current edition hosted as well a two day Conference on Information Visualization and a Symposium on Visual Analytics. In the session I will attempt to summarize the highlights.
26/10/06 15.30	6.08	Haoxiang Wang	Research Group Meeting Distributed Visualization in the Grid My plan will be a combination of an introduction to my work and a talk about three distributed visualization papers/projects followed with a discussion session. Three papers were prepared for the possible attendees to the session. Could you please choose a most interested paper among them and read it? You may be asked to give a short comment on the one you read during our discussion session. Links 1. RAVE: Resource-Aware Visualization Environment The paper presents an architecture for remote, collaborative visualization of dataset over the Grid. The architecture of the system includes a data service, a render service, an active client and a thin client to support wide range of users and hardware. 2. Collaborative Visualization over the Access Grid using the ICENI Grid Middleware The paper talks about a component-based collaborative visualizaiton environment implemented by using the ICENI Grid middleware. Access Grid is integrated with the system, not only for the human presence and interaction, but also for the streaming of a visualization graphic output. 3. e-Viz: Towards an Integrated Framework for High Performance Visualization The e-Viz not only distributed visualization across the Grid, but also tried to provid a generic interface to a set of visualization technologies. The project aimed to reduce the requirement on both visualziation and Grid knowledge for end users, but still provides them the ability to utilize Grid and visualization technologies.
19/10/06 15.30	6.08	Roy Ruddle	Research Group Meeting Trails in Information Spaces My main aim is to gain feedback about a research proposal I'm submitting in a few weeks, titled "Trails in information spaces". I'll be outlining my vision + how I intend to achieve it, and introducing some of the important literature that provides background to the area and the Memories for Life Grand Challenge.
12/10/06 15.30	6.08	Richard Holbrey	Research Group Meeting A Cure for Scatterplots? Given a finite amount of room on your screen, there is inevitably a point at which overplotting becomes a problem. Bertini takes one approach, which is to approximate the density of data using user-perception as a guide. After introducing the the paper, this session discusses other attempts to solve the problem using other techniques and tools such as Xmdv, HCE... and my own efforts, using "Eirik". Notes/Links Bertini et al., "Give Chance a Chance", InfoVis 2006 (5), 95-110
05/10/06 15.30	6.08	John Hodrien Jason Wood	Research Group Meeting Building and Using High Resolution Tiled Displays The VVR Group (through SRIF funding) has constructed high resolution tiled displays. These are configured as a table with approx 23 million pixels and as a wall with 53 million pixels. While these devices are constructed from standard PC components they cannot be used like a typical PC. This talk will cover the hardware (choice/construction/configuration) of these devices, the range of input devices, available software tools and an example application. It is an opportunity for people to ask questions about how to use them and hopefully provide food for thought on research applications.
25/09/06 12.00	6.08	Alexei Sourin Nanyang Technological University, Singapore	Research Group Meeting From a Small Formula to Cyberworlds The talk covers projects on function-based web visualisation and visualisation on Grid. We have proposed and implemented function-based extensions (FX3D/ FVRML) of X3D and its predecessor VRML which allow for defining time-dependent geometric shapes, their appearance and transformations with analytically defined parametric, implicit and explicit functions. The function-defined shapes can be used together with the standard X3D and VRML shapes. Besides defining shapes by analytical functions, we have developed interactive function-based shape modelling tools. We have extended these interactive shape modelling tools to work on the Grid. We have also developed Grid-based portal for rendering animation scene files. Rendering computer animation frames is a very time consuming job. Using parallel computing on clusters and render farms is a common solution to this problem. In this project we developed a framework for Grid rendering services. We have also developed a novel loseless 3D compression method which allowed us to transfer gigabytes of scene representation files (Renderman (.rib) and mental images (.mi) files).
Summer, 2006
01/09/06 10.00a.m.	6.08	Alfred Inselberg School of Mathematical Sciences, Tel-Aviv University, Israel	Research Group/VizNet Event MULTIDIMENSIONAL VISUALIZATION AND ITS APPLICATIONS Parallel Coordinates Tutorial The desire to understand the underlying geometry of multivariate (multidimensional) problems, has motivated several visualization methods to augment our limited 3-Dimensional perception. After a short overview, Parallel Coordinates are introduced and rigorously developed obtaining a one-to-one mapping between subsets of N-space and subsets of 2-space. This leads to constructions algorithms in N-space involving intersections, proximity, interior point construction, line and plane Topologies useful in approximations and Computer Vision, as well as Collision Avoidance Algorithms for Air Traffic Control. It is a VISUAL Multidimensional Coordinate system. Applications to Visual and Automatic Data Mining are illustrated with real multivariate datasets (some with hundreds of variables) together with a Decision Support system capable of doing Feasibility, Trade-Off and Sensitivity Analyses in complex multivariate processes. Notes/Links Tutorial Details and Lecture Notes
10/08/06 15.30	6.08	Rodolfo Allendes	Research Group Meeting See What's Shaking This years IEEE Visualization Design Contest, also named "see what's shaking" promotes the design of meaningful scientific visualizations for large earthquake simulation data produced by the terashake initiative. Having this contest as starting point, my work has focused on the production of a visualization, i.e a video file, which could help seismologists answer domain specific questions related to the behaviour of an earthquake in the California area. Slides - PPT (900k) Video - AVI (8G)
07/08/06 14.00	Active Learning lab.	Prof. Tim David Centre for Bioengineering at University of Canterbury	Research Group Meeting Patient Specific Models of Blood Flow in the Cerebral Vasculature The circle of Willis (CoW) is a ring-like arterial structure located in the base of the brain and is responsible for the distribution of oxygenated blood throughout the cerebral mass. To investigate the effects of the complex 3D geometry and anatomical variability of the CoW on the cerebral hemodynamics, a technique for generating physiologically accurate models of the CoW has been created using a combination of magnetic resonance data and computer aided design software. A mathematical model of the body's cerebral autoregulation mechanism has been developed and numerous computational fluid dynamics simulations performed to model the hemodynamics in response to changes in afferent blood pressure. Three pathological conditions were explored, namely a complete CoW, a fused Anterior Communicating Artery and a missing Posterior Communicating Artery. While a large dataset has been generated as a result of the simulations, the methodology of the cerebral hemodynamic modelling is proposed with the potential for future clinical application in mind, as a diagnostic tool.
03/08/06 15.30	6.08	David Duke Chris Rooney Luke Edwards	Research Group Meeting 1. VMLS: I recently attended a three-day workshop on Visualization in Medical and Life Sciences, organized by the University of Greifswald. Around 40 visualization people were invited, with a strong representation from the US and Germany. Two invited speakers presented life-sciences perspectives and discussed the need for visualization and end-user issues, with technical presentations then setting out relevant work in volume visualization, user interfaces, graph drawing, and applications. In the session I will attempt to summarize the highlights. 2. Clustered Rendering - Summer Project I have been looking at ways of improving the efficiency of rendering large volumes of data using Iris Explorer. I have been focusing on splitting up data and rendering it on several machines in the visulisation cluster, then combining the final product locally. I have found issues with efficiency which is what I am currently trying to deal with. 3. Summer Project A short talk by Luke Edwards on the Project developed as a Summer Intern at VVR.
29/06/06 15.30	6.08	Hamish Carr University College, Dublin	Research Group Meeting On histograms and isosurface statistics We show that histograms represent spatial function distributions with a nearest neighbour interpolation, resulting in systematic under-representation of transitional features of the data, and that isosurface statistics, which use higher quality interpolation, give better representations of the function distribution. We also use our experimentally collected isosurface stats to resolve some questions as to the formal complexity of isosurfaces.
15/06/06 15.30	6.08	Nurul Mohd Noor	Research Group Meeting Asynchronous Collaborative Visualization Asynchronous collaboration is where people work together at different time and different place. This is often less intrusive and demanding than synchronous collaboration, and of course is extremely valuable when the distance separation involves major change of time zones. E-mail has been a 'killer' application in this respect. Yet much of collaborative visualization research has concerned synchronous working. In this talk, I will present a general framework as a medium for asynchronous collaborative visualization. The data model for this framework will be presented in tree form. The history tree will be designed with features that help collaborators to follow the collaborative activities that have been carried out over a period of time and help to extract the dataset needed. Notes/Links Dennis P. Groth, "Information Provenance and the Knowledge Rediscovery Problem," iv, pp. 345-351, Eighth International Conference on Information Visualisation (IV'04), 2004.
08/06/06 15.30	6.08	Nadia Boukhelifa	Research Group Meeting Multiple Views in Visualization Visualization developers are often faced with the question of whether to create a single representation of their data, or to use multiple views. Multiple representations can be more useful when they are coordinated. Hence, to encourage developers to design multi-view visualization systems, a more flexible framework to coordinate views is needed. In fact, a system survey revealed gaps in coordination research, and that current visualization systems tend to embed coordination in an ad hoc fashion. However, whereas embedded coordinations are more suited to explanatory visualization systems, more flexible coordinations should be designed for exploratory visualization where views may be added dynamically. In this talk I will discuss current techniques for coordinating multiple views in information visualization, describe some of the work I have been doing in Kent to coordinate web search results data (using multiform glyphs), and a more generic coordination framework that I have been working on for my PhD.
25/05/06 15.30	6.08	David Duke	Research Group Meeting Fine grained visualization pipelines and lazy functional programming This talk describes recent work by Rita Borgo and myself in collaboration with Colin Runciman and Malcolm Wallace from York. Within the EPSRC "Lazy Polytypic Grid" project we are exploring how new technologies for functional programming can be used as a foundation for grid-enabled visualization. Our first results explore how an apparently well-understood algorithm like marching cubes can be reconstructed in quite a different way using functional abstractions: rather than traversal of a (monolithic) dataset,. a stream-based approach has been developed, that uses demand-driven computation to avoid recomputing interpolants. The talk will introduce lazy functional programming, describe its relevance to visualization and computations on the grid, set out our initial results, and outline future directions.
18/05/06 15.30	6.08	David Duke John Hodrien Sean Wang	Research Group Meeting Report on CoLaB visit to China A report on the recent visit to China as part of the e-science sister project, CoLaB. The project is a collaboration between Leeds and Beihang in China, and is using visualization as a demonstration of inter-operability of Grid infrastructures in the two countries. Ultimately it may lead to worldwide visualization collaboratories...
11/05/06 15.30	6.08	Ken Brodlie Richard Holbrey	Research Group Meeting 1. Schoolgirls, football fixtures and high-dimensional visualization Slides - PPT (600k) A short talk by Ken Brodlie 2. Query driven Visualization of Large Data Sets Stockinger et al ( PDF). Introduced by Richard Holbrey.
27/04/06 15.30	6.08	Roy Ruddle	Research Group Meeting How can models of the process of visualization be used to improve visualization tools? Notes/Links "A model for the visualization exploration process" Jankun-Kelly, T.J.; Kwan-Liu Ma; Gertz, M. IEEE Visualization, 27 Oct.-1 Nov. 2002 Page(s):323 - 330 Digital Object Identifier 10.1109/VISUAL.2002.1183791
Spring, 2006
23/03/06 15.30	6.08	Norman Murray University of Salford	Research Group Meeting An Immersive Assembly and Maintenance Simulation Environment The talk will outline the development of a virtual environment for constraint based assembly and maintenance task simulation and analysis of mechanical products. Procedures and environments for realistic component assembly, constraint recognition, automatic disassembly sequence generation, and maintenance review and training are presented. The simulation of maintenance operations allows for maintenance to be addressed early in the design stages. This reduces unforeseen problems creeping into the design as it progresses through its life cycle, consequently saving both time and money while improving product quality.
16/03/06 15.30	6.08	Mini Workshop	Research Group Meeting Mini-workshop and demonstrations by various members of the group Adriano - visual representations of errors in isocontouring. Marcelo - focus and context volume rendering. Kan Liu - color models and self-organized mapping for visualization of high dimensional datasets. Rita - flowlines fluid animation video Notes/Links Flowlines fluid animation reel
09/03/06 15.30	6.08	Rita Borgo	Research Group Meeting Space Filling Curves and their Application to Storage and Retrieval of Multi-Dimensional Data. In 1878 George Cantor demonstrated that any two finite-dimensional smooth manifold, independently of their dimension, have the same cardinality. The Cantor finding implies, in particular, that the interval [0,1] can be mapped bijectively onto the square [0,1]². In 1879 it was demonstrated that such a bijective mapping is necessarily discontinuous. Dropping the bijectivity condition in 1890 Peano constructed a curve representing a surjective mapping from [0,1] onto [0,1]², i.e. a curve that passes through every point of a two-dimensional region with positive area. Curves with this property are now called Space-Filling Curves or Peano Curves. Space Filling Curves are often used in Computer Science as locality preserving hashing function (i.e. Morton Ordering). In this seminar we will go through the mathematical theory at the base of the construction of a space filling curve and present some of the major results existing in literature regarding the application of these primitives to storage and retrieval of n-dimensional data.
02/03/06 15.30	6.08	Roy Ruddle	Research Group Meeting Tales of Trails Trails have played a pivotal role in the way people navigate in the real world for thousands of years, and were proposed as an important aid to navigation in information spaces before the first programmable computers even existed (see Bush's "As we may think", Atlantic Monthly, 1945). I will outline the uses of trails to reduce the physical and cognitive effort involved in navigation, briefly describe some experiments I have run to investigate the effects of trails when people navigate 3D virtual environments (VEs), and then focus on my attempts to design algorithms that automatically process large quantities of raw movement data to extract trails that ar a useful aid to navigation. Potentially, these could be used in VEs, the real world and information spaces.
23/02/06 15.30	6.08	Trevor Dodds	Research Group Meeting Collaborative Interaction in Virtual Environments What's missing from collaborative interaction in virtual environments that is present in the real world? This talk will provide an outline of collaborative interaction, giving data visualization and urban planning applications as examples. I will present a paper prototype for my collaborative virtual environment (CVE) using urban planning as a context. I will present some novel forms of interaction that I intend to implement, and discuss one, 'group dynamics', in more detail. Group dynamics is a socially driven form of interaction that can be simulated in a CVE. In the real world, we don't communicate or operate as one large group. We divide up tasks, split into subgroups, talk to large numbers of people or create side channels of communication. This can be implemented whilst taking advantage of the fact that real world contraints don't have to apply.
16/02/06 15.30	6.08	Ken Brodlie	Research Group Meeting Contouring and Isosurfacing with Uncertainty In the classical visualization techniques of contouring and isosurfacing from gridded data, the fundamental step is to estimate the intersection of the contour line or isosurface with the grid lines - by inverse linear interpolation of the values at the grid points. But what happens if these values are known to have an associated error or uncertainty? The talk will propose a new approach in which - rather than represent the intersection as a 'point' - we represent it as a probability density function. The 2D contouring problem is transformed from isoline extraction to image display of the derived pdf, and the 3D visualization problem is transformed from isosurface extraction of the original data to direct volume rendering of the derived pdf. The work is at an early stage and somewhat speculative, and so audience feedback is important! The work is being done in collaboration with Adriano Lopes who is visiting Leeds in February and March.
09/02/06 15.30	6.08	Ben Hammett Sharp Research (Oxford)	Research Group Meeting 3D Displays I shall give a quick introduction to Sharp Laboratories of Europe (SLE), where we sit within the Sharp Corporation, what we do, and where the work that I carry out in the 3D contents team fits within the company. SLE have developed the SmartStereo SDK, a set of protocols that allow the developer to set the amount of depth that they would like the viewer to experience in front of and behind the display. Based on these preferences the SDK adjusts the stereo viewpoints of a scene enabling easier development and more comfortable viewing for the user. I will explain how we use this in the development of our 3D content, as well as giving a quick outline of other projects that we are currently working on. Notes/Links IEEE Vis Contest 2006
02/02/06 15.30	6.08	David Duke	Research Group Meeting Inference and Visualization (slides - PDF 300K) What is visualization? Answers to this question usually involve words such as understanding, perception, insight, data, and pictures. Taxonomies and ontologies have been used to at tease out what people believe are important components. Nether the less, there seems to be a big gap between these generic ideas, and the research into techniques and representations. This (short) talk is tentative, putting forward a different view of visualization founded on notions of inference: given a set of facts, what kinds of conclusions can be drawn? I will go through three different kinds of inference, and try to explain their relevance to understanding visualization - and in particular, how they abstract away from differences between scientific and information visualization. Notes/Links Roy's report from the e-Science Usability Workshop Usability Roadtrip paper "White coats and fingerprints: diagnostic reasoning in medicine and investigative methods of fictional detectives."
26/01/06 15.30	6.08	Rita Borgo	Research Group Meeting Dealing with Massives Volumetric Visualisation: Progressive Algorithms and Data Structures Projects dealing with massive amounts of data need to carefully consider all aspects of data acquisition, storage, retrieval and navigation. The recent growth in size of large simulation datasets still surpasses the combined advances in hardware infrastructure and processing algorithms for scientific visualization. The cost of storing and visualizing such datasets is prohibitive, so that only one out of every hundred time-steps can be really stored and visualized. To address these issues we propose an elegant and simple to implement framework for performing out-ofcore visualization and view dependent refinement of large volume datasets. We adopt a method for view dependent refinement that relies on longest edge-bisection strategies yet introducing a new method for extending the technique to the field of Volume Visualization while keeping untouched the simplicity of the technique itself. Results in this field are applicable in parallel and distributed computing ranging from cluster of PC's to more complex and expensive architectures.
Winter, 2005
20/12/05 13.00	VVR Christmas Lunch.
08/12/05 15.30	ALL (9.30a)	Jason Wood	Research Group Meeting - Last of 2005 Providing User Interfaces to Distributed Visualization Systems The eViz project is attempting to create a system to aid users with high performance visualization tasks. It aims to aid the user, if required, in generating a visualization pipeline and then finds suitable software and hardware on which to execute it. To allow the user to interact with these dynamicaly specified piplelines requires some form of user interface. One of the Leeds contributions to this project is to look at providing a flexible user interface framework to control distributed visualization systems. eViz website
01/12/05 15.30	6.08	Richard Holbrey	Research Group Meeting Visual Techniques for Astronomy A review of my efforts to bring together data mining and visualization, and the importance of data handling and dimensional reduction. A useful thing to read anyway is Fodor's "A survey of dimension reduction techniques" (2002). Some of the detail is scant, but there's a whole lot on wikipedia these days. A survey of dimension reduction techniques
24/11/05 15.30	6.08	Hamish Carr University College, Dublin	Research Group Meeting Flexible Isosurface Interfaces to Scalar Volumetric Data Many scientific and medical domains generate sampled scalar fields representing the spatial distribution of a physical property in a volume of interest. Tools such as isosurfaces and volume rendering have been developed for visualizing these data sets, but often have problems such as visual occlusion when a single test of feature importance is used throughout the data. We present an interface which uses topological analysis of the scalar field to accelerate isosurface rendering and to allow user control over individual isosurface components. We also show how this interface can be adapted to provide topologically local transfer functions for volume rendering. Hamish is visiting the group all day.
16 - 18/11/05	n/a	Adriano Lopes Universidade Nova de Lisboa, Portugal	Visiting the group.
16/11/05 Afternoon	Various	(Roy Ruddle)	VVR Open House
14/11/05 All day	n/a	Samara Alzaidis University of Canterbury, New Zealand	Visiting the group. Links Bioengineering Centre Modeling arterial blood flow in the brain
03/11/05 15.30	6.08	Marcelo Cohen	Research Group Meeting Programming the GPU (... and a brief intro to OpenGL SL) (slides - PDF, 1.4Mb) This talk covers GPU evolution towards a programming model based on high level shading languages and also presents a brief introduction to the OpenGL Shading Language and the OpenGL 2.0 API for shader development.
27/10/05 15.30	6.08	Trevor Dodds	Research Group Meeting Collaborative Interaction in Virtual Environments Collaborative virtual environments (CVEs) are three dimensional electronic worlds that make use of social simulations (avatars and communication) and shared information (e.g. 3D design models). CVEs use distributed (networked) systems, and often have users in separate locations that need to access remote resources. The aim of our research is to develop methods that allow users to interact as easily in CVEs as they do when physically co-located in the real world. The usability issues involved are similar to those encountered in e-Science topics where information is shared visually in real time. Notes/Links Open Croquet (Alan Kay) Virtual Rehearsals(UCL) Collaborative VEs (Brazil)
20/10/05 15.30	6.08	James Handley	Research Group Meeting Multivariate Visualization of Cardiac Virtual Tissue This problem has arisen in the e-science Integrative Biology project where biologists are studying the electrical behaviour of cardiac tissue - but is widely applicable. The results of a cardiac simulation are a number of variables (such as voltage, ion concentration, etc), measured across a 2D slice, and where these variables change over time. So we might have a dozen variables, over a 256x256 grid, over 1000 time steps. What is the best way to present this information?
13/10/05 15.30	6.08	David Duke	Research Group Meeting What Drawing Trees tells us about Visualization, by Pat Hanrahan (slides) At InfoVis 2001 Pat Hanrahan (Stanford) gave a keynote talk on "How to Draw a Tree". Apart from being a wonderfully entertaining talk, the exploration of an apparently narrow topic - tree drawing - throws up a number of fundamental questions in visualization. One of these, the relationship between external and internal representations, is one we have all probably encountered. But two further issues are possibly less familiar: the need to mix metaphors, and the importance of aesthetics in depiction. In the session, I will go through the talk that Pat Hanrahan gave, but without of course the benefit of his experience and knowledge!
06/10/05 15.30	6.08	Ken Brodlie	Research Group Meeting 10 Unsolved Problems in Information Visualization, by Chaomei Chen. PDF Notes/Links Kosara et al User Studies paper Edward Tufte web site Chris Johnson's unsolved problems Informatics MSc student papers on evaluating vis The Value of Visualization, Jarke J. van Wilk. IEEE Vis Oct 2005.

Time/Date

Location

Who

Event

Winter, 2007

28/02/08
14.30

6.08

Roy Ruddle,
Nadia Boukhelifa

Research Group Meeting

Memory for my life's travels:
- Usage scenarios (why store this information?)
- Narratives (to link memories together; time, person, place, topic ...)
- How to present, filter, organise, cue ...
(Slides - PPT)
Visualizing clusters in spatio-temporal data and images
How to combine hierarchical structures with spatio-temporal data and images in a way that is visually informative. What visualization methods would be useful to visualize trees of features (e.g. features describing clusters in a video sequence) on the image itself (or the video sequence)? (Slides - PPT)

21/02/08
14.30

6.08

Jason Wood,
Katarzyna Boronska

Research Group Meeting

Visualizing Air Quality Data
The UK collects air quality data consisting of a range of chemical species (ozone, CO2, NO etc.) at a selection of monitoring sites (Leeds City Centre, Ladybower Reservoir etc.) delivered as hourly averages. We wish to use this data to motivate the use of a stateful web based visualization service. What would be an interesting set of visualization methods that would benefit from repeated interactions ?
Perfectionist's issues with simple 2D geometries
Simulations of pattern-forming systems often produce a large number of simple 2D fields. 3D-oriented tools do not seem adapted to efficiently process such data sets.
(Slides - ODP)

07/02/08
15.00

Active Learning Lab (9.30a)

Prof. John Davies
BAE Systems Insyte

Research Group Meeting

Use of computing in large distributed military systems
Computing is the major component of all military systems. From real-time array processing that drives sensors, through complex algorithms that enable recognition, through picture compilation and visualisation, recognition, threat analysis and assignment, and networking across all the units engaged in the operation, computing plays a vital role that enables timely, co-ordinated and successful operations. However, as well as the technology; the production, inter-operation and maintenance of such systems present major challenges. These include the use of Architecture Frameworks, major systems integration programmes, issues of productisation, and development and maintenance issues for large programmes and systems produced by large teams across multiple sites and with many stakeholders. This seminar will discuss some of the systems and challenges and how they are being addressed.

31/01/08
16.00

6.08

Darren Treanor
LIMM - Faculty of Medicine and Health,
University of Leeds

Research Group Meeting

An evaluation of virtual slides
This seminar will describe the findings from an evaluation of virtual slides that has been conducted with trainee and consultant histopathologists.

29/01/08
14.00

9.30a

Dr John Maxfield, Technical Director and Founder, Icona Solutions Limited

Research Group Meeting

From VITAL Proof of Concept to aesthetica: Product Evolution and Technical Challenges
VITAL (Visualising the Impact of Tolerance Analysis) was an EPSRC funded research project undertaken within the School of Computing from 1997-2001 in partnership with industrial collaborators from the Automotive Industry, including Jaguar, Rover Group and Magna. With the financial backing of the White Rose Seedcorn Fund, a University Spin-of-Company, Icona Solutions Limited, was formed in 2002 for the commercial exploitation of the results of the VITAL project. Icona's main product, aesthetica, has evolved directly from the original proof of concept system developed within the VITAL project and is now used by many of the world's largest automotive manufacturers and suppliers including General Motors, Chrysler, Nissan, VW, Porsche, Bentley, Hyundai, Renault, EDAG, and PATAC. In this presentation I will review the evolution of the aesthetica product and the technical challenges that were faced in developing a commercial software product from the original proof of concept system.

Notes/Links
John was a researcher in the School of Computing from 1992-2002. He started as one of the three initial Keyworth Scholars in the Keyworth Institute of Manufacturing and Information System Engineering (which was then directed by Professor Alan de Pennington). John's PhD topic was "A Distributed Virtual Environment for Concurrent Engineering". It was based upon the PhD of Mingxian Fa who undertook the relevant basic research on 3D interactive constraint-based solid modelling in the School of Computing from 1989 t0 1993. John subsequently became an SGI Fellow (1995-1997) and focused on identifying exploitable engineering applications for virtual environments which used the results from his PhD. During this period he was also responsible for establishing the School's Virtual Environment Laboratories funded by the Informatics Institute. The equipment included a flat bed Holobench for 3D interactions in a virtual environment. This research culminated in the VITAL project and spin-off company Icona Solutions Limited described in John's abstract.

24/01/08
14.00

Staff Room

Natasa Milic-Frayling Integrated Systems
Microsoft Research ,
Cambridge

Research Group Meeting

Web Site Structure Analysis
Web browsers provide support for browsing and re-visiting sites on the Web, including Back and Forward buttons, History, Favourites, and auto-complete for URL typing. These features complement navigation menus, filters, site search and other means for accessing content that are incorporated in the Web site design. While the general browsing behaviour has been studied extensively over the years, less attention has been given to the structure of individual Web sites and their characteristics. In this presentation we introduce Link Structure Graphs (LSG), a new technique for representing and studying the hyperlink structure of Web sites. We illustrate how LSG can be used to partition a site into coherent organizational units referred to as sub-sites. The LSG approach was motivated and evaluated through several user studies. The studies informed on the basic LSG concepts and assessed the effectiveness of LSG representation for identifying entry pages of sub-sites. We present relevant aspects of the user studies and discuss possible applications of the sub-site discovery research. This research is conducted at Microsoft Research Lab in Cambridge by a team of researchers: Eduarda Mendes Rodrigues, Blaz Fortuna, Gavin Smyth, and Natasa Milic-Frayling.

Notes/Links
Slides - PDF (900k)

17/01/08

Newcastle

Ken Brodlie

VizNet NE Region Visualization Seminar

13/12/07
16.00

6.08

Melvin Hoare
Astrophysics Group
School of Physics and Astronomy,
University of Leeds

Research Group Meeting

Surveying our Galaxy
I will describe the types of astronomical data being generated by the current new generation of surveys of our Milky Way galaxy and the questions that these data can address. The challenges and opportunities afforded by the large volumes and varied nature of the datasets will be highlighted.

Notes/Links
The theme for the 2008 IEEE Visualization Design Contest is Multifield 3D Scalar Data. The subject is a galaxy cluster simulation data set submitted by Mike Norman and Robert Harkness.

06/12/07
16.00

6.08

Zhesi He
University of York

Research Group Meeting

Visualisation and Navigation of High-dimensional Bioinformatics Data
The talk will discuss the use of interactive visualisation techniques and various multivariate data analysis methods and development of an interactive visualisation based tool for bioinformatics researches. After a survey on existing methods and tools for various multivariate data analysis studies, we believe that visualisation and interaction approaches facilitate rich information gathering and thus provide better understanding in data exploration. To test applicability of our design, a demonstration tool Vitamin-B (Visual, Interactive Tool for Analysing and MINing Bioinformatics data) was developed and a formal user-based evaluation was performed on selective case studies. Based on encouraging results from the performance and usability evaluations, we conclude that our system has proven that the benefit of interactive visualisation particularly in terms of linking, undo and system integration functionality that makes iterative analysis and drill down operations much easier and quicker to perform. Briefly, we identify future extensions of this project. It is our hope that our prototype will evolve into a system in real use for bioinformatics researchers.

Autumn, 2007

29/11/07
16.00

6.08

Saira Pathan

Research Group Meeting

Visualization as a Tool for Neurosurgery
Visualization is all about gaining insight and understanding. The roles of visualization in medicine are manifold. First, visualization allows an insight to complex anatomy. Second, it provides assistance to medical professionals at different levels of treatment. And finally, it is used as a teaching and training tool for medical students and trainees. My research focus is to use visualization as a training tool for neurosurgery particularly brain tumour biopsy. In this talk, I will present the work done so far and discuss my crazy ideas.

21/11/07
15.30

6.01
6.02
6.08

(Roy Ruddle)

VVR Open House

Details to follow.

15/11/07
16.00

6.08

Dave Harrison

Research Group Meeting

Using Scene Graphs for Creating 3D Scenes
A scene graph is a representation of a graphics model as an acyclic directed graph of heterogeneous nodes of geometries, properties and transformations, allowing common properties of entire sub-graphs to be grouped in parent nodes. A scene graph is a retained mode graphics API in that the graph persists in memory between frames which allows for optimisations that are not available to the less organised stream of graphics primitives generated by underlying immediate mode API's, such as OpenGL or DirectX. Several mature open source scene graph libraries exist that offer a number of optimisations and facilities to reduce the burden on the programmer and graphics pipeline in creating complex 3D scenes. We will discuss the development of a scene using a simple in house scene graph implementation, then move on to some of the advanced features commonly provided by fully fledged scene graph libraries.
Slides - TBZ

08/11/07
16.00

6.08

David Duke,
Saira Pathan

Research Group Meeting

Report on from IEEE Visualization 2007 Conference
A group of us recently attended the IEEE Visualization Conference in Sacramento. This is the major international visualization workshops and the current edition hosted as well a two day Conference on Information Visualization and a Symposium on Visual Analytics. In the session they will attempt to summarize the highlights.

25/10/07
16.00

6.08

Rita Borgo,
David Duke

Research Group Meeting

"Though this be madness, yet there is method in it": The Importance Of Mathematical Concepts Beneath Contemporary Visualization.
Visualization occupies an important role in the pursuit of knowledge as the understanding of real world phenomena. However, behind the image are mathematical models of the world and its representation. At a time when questions about the very core of the discipline, e.g. the relationship between information and scientific visualization, are being raised almost annually within the conference, it seems particular germane to stand back and review what is ultimately what could be the most abstract and neutral picture of visualization itself - the mathematics world which ties together the notion of data and transformation. The panel will involve lively discussion and debate on the kinds of mathematics applicable to visualization and the means by which maths is brought into the discipline. After summarizing the 'case for the defence', members of the panel will be cross-examined by the audience on whether their own work is the madness of genius, or the product of mathematical methods. The deeper question, however, is whether a mathematical civilization beats at the heart of the visualization community.

Notes/Links
IEEE Visualization Conference 2007, Panel Session

18/10/07
16.00

6.08

Hamish Carr
School of Computer Science & Informatics, University College Dublin

Research Group Meeting

Topological Quantitation for Medical Problems
(based on collaborations with Linkoping, UCD and UC Davis colleagues)

Where scientific and engineering visualizations frequently focus on qualitative results - i.e. understanding a system, medical applications frequently require quantitative results that can be recorded for future reference and comparison. Quantitative results, however, often require a preliminary qualitative stage - segmentation. We will show how quantitative information can be integrated with the qualitative segmentation by using topology to link the two stages.

12/10/07
14.00

6.08

Hamish Carr
School of Computer Science & Informatics, University College Dublin

AG Seminar (Manchester University)

(No) More Marching Cubes
Isosurfaces, one of the most fundamental volumetric visualization tools, are commonly rendered using the well-known Marching Cubes cases that approximate contours of trilinearly-interpolated scalar fields. While a complete set of cases has recently been published by Nielson, the formal proof that these cases are the only ones possible and that they are topologically correct is difficult to follow. We present a more straightforward proof of the correctness and completeness of these cases based on a variation of the Dividing Cubes algorithm. Since this proof is based on topological arguments and a divide-and- conquer approach, this also sets the stage for developing tessellation cases for higher-order interpolants and for the quadrilinear interpolant in four dimensions. We also demonstrate that, apart from degenerate cases, Nielson's cases are in fact subsets of two basic configurations of the trilinear interpolant.

11/10/07
16.00

6.08

Benjamin Blundell

Research Group Meeting

Visualising Change in Semantic Graphs
Details to follow

Summer, 2007

21/06/07
15.30

6.08

Nadia Boukhelifa

Research Group Meeting

The Uncertain Reality Of Underground Assests
Visualization may be a potent looking-glass for peering into both physical and abstract worlds, but our view is always distorted by inaccuracies in measurements, incompleteness of knowledge, and ambiguities in interpretation. To the visualizer, uncertainty is a particular problem. Depiction depends on the placement of marks on paper or screen, and the placement of such a mark can, implicitly, convey confidence that this feature is in this place rather than another, or even that the existence of the feature is accepted and agreed. In this paper, we use the term uncertainty visualization to refer to the problem of acquiring, modelling and representing data while accounting explicitly for the uncertainties that encompass it. We provide an overview of this growing area, and discuss methods of systematically incorporating knowledge of uncertainty in a geovisualization application. We report on ongoing research in a major industrial application to visualize buried assets while reflecting the uncertainty of our knowledge.

07/06/07
15.30

6.08

Rodolfo Allendes Osorio

Research Group Meeting

Developments in uncertainty visualisation
Though there have been efforts to include different types of uncertainty into visualisation, these have not focused in the complete integration of uncertainty with the traditional visualisation pipeline. In my presentation, I will review the approach I have been following to manage uncertainty throughout the visualisation process and the results I have obtained so far.

31/05/07
15.30

6.08

Casper Engelen

Research Group Meeting

Website Visualization
How to visualize the structure of a large website?" is the main question I tried to answer in the last couple of months. This talk will be about my approach to this task, what sort of problems occured and the results achieved so far.

23/05/07
16.00

6.08

Jeremy Walton, NAG Ltd, Oxford.

Research Group Meeting

Principles Of Visualization Design: The Good, The Bad and The Ugly
Using visualization packages to turn numerical data into pictures can lead to better understanding, but only if the image is a good representation of the data. So what makes one visualization better than another? Although hard and fast rules probably can't be established for all circumstances, the consideration of several examples (good, bad and ugly) might lead to some general principles that could be applied when designing a visualization. This talk will attempt to elucidate them.

10/05/07
15.30

6.08

Hamish Carr
School of Computer Science & Informatics, University College Dublin

Research Group Meeting

Topology-Controlled Volume Rendering
Abstract-Topology provides a foundation for the development of mathematically sound tools for processing and exploration of scalar fields. Existing topology-based methods can be used to identify interesting features in volumetric data sets, to find seed sets for accelerated isosurface extraction, or to treat individual connected components as distinct entities for isosurfacing or interval volume rendering. We describe a framework for direct volume rendering based on segmenting a volume into regions of equivalent contour topology, applying separate transfer functions to each region. Each region corresponds to a branch of a hierarchical contour tree decomposition, and a separate transfer function can be defined for it.

Notes/Links
"Topology-Controlled Volume Rendering"
GH Weber, SE Dillard, H Carr, V Pascucci, B Hamann
IEEE Transactions on Visualization and Computer Graphics, March/April 2007 (Vol. 13, No. 2) pp. 330-341

03/05/07
15.30

6.08

Chris Rooney

Ken Brodlie

Research Group Meeting

1. Interaction with High Resolution Displays - The Story so Far
My talk will be derived from the work I have been done so far this year. I will focus on an analysis on current classifications of interaction techniques, and how I can build on these to create a new taxonomy. They'll be a group discussion on a potential new taxonomy, so bring your thinking caps!

2. A Visualization Timeline
Rae Earnshaw (Univ of Bradford) is guest editor of a special issue of IEEE CGA on 'Discovering the Unexpected' (which will cover Visual Analytics) and is considering including in his foreword a timeline for visualization.

27/04/07
14.00

6.08

Robert S Laramee Department of Computer Science, Swansea University

Research Group Seminar

The Search for Meaningful Flow
Swirl and tumble motion are two important, common fluid flow patterns from computational fluid dynamics (CFD) simulations typical of automotive engine simulation. We study and visualize swirl and tumble flow using several advanced flow visualization techniques: direct, geometric, texture-based, and feature-based. When illustrating these methods, we describe the relative strengths and weaknesses of each approach across multiple spatio-temporal domains typical of an engineer's analysis. The result is the most comprehensive, systematic search for swirl and tumble motion ever performed. Based on this investigation we offer perspectives on where and when these techniques are best applied in order to visualize the behavior of swirl and tumble motion.

Notes/Links
http://www.vrvis.at/scivis/laramee/MotionExtracted/

26/04/07
15.30

6.08

Nurul Mohd Noor

Research Group Meeting

Visualization Notations, Models and Taxonomies
Visualization taxonomies are an important means of imposing some structure on a rather diverse field. In this talk, I will present a fresh look of visualization reference model as an evolution of previous models and suggest a new style of notation called Domino Notation. This work may help in develop a visualization taxonomies and contribution to research on ontology. The aim of this research is to describe visualization in a clear and precise way than it is possible at present. This will have benefits in long term archiving of visualizations so they can be recreated long after the software that generated them has expired and also in applications such as asynchronous collaborative visualization where a precise description is needed in order to exchange description between collaborators. Comments and feedback are most welcome.

25/04/07
13.00

Roger Stevens Building
LT1 (ground floor)

John S. Hughes
Sony Pictures Visual Effects, Hollywood

Talk on CG in Film Industry

An Insider's Look at Hollywood Special FX
John was in Leeds for 10 years as undergrad, PhD student and Postdoc Research Fellow, before moving to Industry, and ending up as Visual Effects developer for films like Harry Potter, and Spiderman. John is visiting Leeds, and offered to talk about his work.

Notes/Links
http://www.johnshughes.com/

19/04/07
15.30

6.08

Roy Ruddle

Research Group Meeting

Report on IEEE Virtual Reality Conference 2007, Charlotte, USA
I'll report on this year's IEEE Virtual Reality conference 2007 in Charlotte, USA, and ask you about your mental representation of a website (come armed with pen + paper).

Spring, 2007

08/03/07
15.30

6.08

Ken Brodlie

VizNet NE Region Visualization Seminar

Temporary Venue Details

22/02/07
15.30

6.08

Tim Hattrell School of Mechanical Engineering, University of Leeds

Research Group Meeting

Surface Smoothing and Curvature
Tim is a Research Fellow in the Combustion Group. He will explain to us the background to his research in premixed turbulent combustion. They have obtained 3D flame volume information by scanning a laser sheet through the flame, and wish to display the flame surface and importantly make calculations such as surface curvature. Marching cubes does not give the results he wants, so the purpose of the informal meeting is to discuss approaches to smoothing isosurfaces so as to enable such calculations.

15/02/07
15.30

6.08

Trevor Dodds

Research Group Meeting

Collaborative Interaction in Virtual Environments - Mobile Group Dynamics
Previously I have presented to the group a system prototype for evaluating group dynamics within a Collaborative Virtual Environment (CVE), using the context of urban planning.
Group dynamics are often studied within a socially driven context in real life, and clearly CVEs can create a visually realistic imitation of the real world to draw on existing social conventions. However, even since early days of VE research, it has been highlighted that "new ways of thinking...must be adopted if VR is to fulfill its potential" (Slater et al. 1994), "CVEs...do not necessarily need to reflect or embody the characteristics of conventional environments to enable them to support particular forms of activity or interaction" (Fraser et al. 2000), "This is the trap VR often falls into; VR tries to imitate reality..." (Pekkola, 2002).
Last term I ran two experiments, one of which evaluated Mobile Group Dynamics (MGDs) within the urban planning review system. My talk will look at how groups are conventionally implemented in CVEs, and what functionality I have added to support better collaboration by removing real world constraints and providing support for "mobile" groups working in a large-scale space. Whilst allowance is made for "manual" group work and real world conventions, the MGDs facilitated are designed specifically for and are directly applicable to the virtual world. I will present a summary of the experiment results and welcome any comments/feedback.

08/02/07
15.30

6.08

Tim Wright
School of Earth and Environment, University of Leeds

Research Group Meeting

Earth-shattering proof of continents on the move
(extract from the Reporter 29 January 2007)
Africa is being torn apart. And as Ethiopia's rift valley grows slowly wider, an international team of scientists is taking a unique opportunity to plot the progress of continents on the move. The 28-strong team is led by University of Leeds geophysicist Dr Tim Wright, who has secured a 2.5 million grant from the Natural Environment Research Council (NERC) to study the seismic events taking place in the remote Afar desert of Northern Ethiopia. His team, which includes experts from Oxford, Cambridge, Bristol and Edinburgh universities, as well as international researchers from the US, New Zealand, France and Ethiopia, will also use GPS, seismometers, and other geophysical and geochemical techniques to determine the properties of rock and magma below the surface, and to monitor the crust's movement. They will use the data to create a 3D computer model of how magma moves through the Earth's crust to make and break continents.

01/02/07
15.30

6.08

Matthew Birtwisle

Research Group Meeting

A 6-DOF Gravity Compensation Scheme for a Phantom Premium Using a Neural Network
Current uses of haptic hardware such as the Phantom Premium 6DOF for surgical simulators lack the desired interface transparency and could cause artefacts in the training regime of a student training on a simulator.
We address this problem using a neural network to interpolate between empirically discovered data points to generalise over the entire workspace; providing the necessary force/torque vector to send to the Phantom to counteract gravitional forces. A 3DOF gravity simulator is produced, along with an initial 6DOF simulator.

25/01/07
15.30

6.08

Rita Borgo

Research Group Meeting

Creating The Motion Illusion
The talk will cover a paper from Freeman, Adelson and Heeger entitled "Motion Without Movement"[1]. They describe a method for assigning perceptual motion to objects that remain in fixed positions, by applying local filters and continuously varying their phase. This technique is used to create continuous display of instantaneous motion at a relatively low cost.

The aim is to gather opinions and ideas about feasibility of this kind of approach for creating vector fields animation.

Notes/Links
[1] Freeman, W.T., Adelson, E.H and Heeger D.J. "Motion Without Movement", ACM Computer Graphics, vol. 25, no. 4, (SIGGRAPH 91), pp. 27--30

Slides - ZIP (8Mb)

12/01/07
13.00

Active Learning Lab.

Ken Brodlie

Envisioning Information 2007 Conference

Students of the Envisioning Information module within the School of Computing MSc programmes will be presenting their research works developed as part of the module assignements. Presentation will be in the form of an internal Conference, full Conference programme available at Envisioning Information 2007 Conference

Winter, 2006

14/12/06
15.30

VVR Christmas Lunch.

07/12/06
15.30

6.08

Chris Goodyer

Research Group Meeting

What Do Oxford Want?
What Do Oxford Want? The Integrative Biology project is a multi-million pound multi-site project looking a what causes heart failure and how cancer tumours develop and grow. Together these diseases account for about 60% of UK deaths. The project brings together numerical modellers, computer scientists and heart and cancer specialists.
As part of the visualisation strand we have been asked to look at providing "cool visualisations" of some physiological heart data from a group in Oxford. In particular how to show two very high resolution datasets of the same heart collected in different ways.

In this talk I shall present the work done so far and be looking for ideas as to what the next stages should be.

30/11/06
15.30

6.08

Nadia Boukhelifa

Research Group Meeting

Perceptually-motivated visualizations - preattentive processing and visualization design
This talk is based on an ACM paper by Healey et al.[1] and online material on perception in visualization also by Healey [2]. The articles argue for using perception research to assist in the design of visualization tools. In particular, they use findings from preattentive processing research to design visualization applications which require rapid detection of data groups and boundaries, target detection and estimation.
I will briefly describe some of the theories behind preattentive processing and move on to talk about example visualization applications that implement such theories. In theory, utilising preattentive processing in visualization design is a powerful idea, but in practice, can this scale to non-trivial visualization problems?

Notes/Links
[1] Healey,C.G., Brooth,K.S., and Enns,J.T. "Visualizing real-time multivariate data using preattentive processing", ACM Transactions on Modeling and Computer Simulation 5,3, (1995), 190-221.]
[2] Healey Lecture Notes

22/11/06
Afternoon

Various

(Roy Ruddle)

VVR Open House

Details to follow.

16/11/06
15.00

6.08

Rita Borgo

Research Group Meeting

Multi-cultural visualization: How functional programming can enrich visualization (and vice versa)
In this talk we present recent advances in the design and implementation of pure functional programming languages that, significantly, contain important insights into questions raised by the recent NIH/NSF report on Visualization Challenges. We argue and demonstrate that modern functional languages can cope with some of the issues raised by the report.

09/11/06
15.30

6.08

David Duke

Research Group Meeting

Report from IEEE Visualization 2006 Conference
A group of us recently attended the IEEE Visualization Conference in Baltimore. This is the major international visualization workshops and the current edition hosted as well a two day Conference on Information Visualization and a Symposium on Visual Analytics. In the session I will attempt to summarize the highlights.

26/10/06
15.30

6.08

Haoxiang Wang

Research Group Meeting

Distributed Visualization in the Grid
My plan will be a combination of an introduction to my work and a talk about three distributed visualization papers/projects followed with a discussion session. Three papers were prepared for the possible attendees to the session. Could you please choose a most interested paper among them and read it? You may be asked to give a short comment on the one you read during our discussion session.

Links
1. RAVE: Resource-Aware Visualization Environment The paper presents an architecture for remote, collaborative visualization of dataset over the Grid. The architecture of the system includes a data service, a render service, an active client and a thin client to support wide range of users and hardware.
2. Collaborative Visualization over the Access Grid using the ICENI Grid Middleware The paper talks about a component-based collaborative visualizaiton environment implemented by using the ICENI Grid middleware. Access Grid is integrated with the system, not only for the human presence and interaction, but also for the streaming of a visualization graphic output.
3. e-Viz: Towards an Integrated Framework for High Performance Visualization The e-Viz not only distributed visualization across the Grid, but also tried to provid a generic interface to a set of visualization technologies. The project aimed to reduce the requirement on both visualziation and Grid knowledge for end users, but still provides them the ability to utilize Grid and visualization technologies.

19/10/06
15.30

6.08

Roy Ruddle

Research Group Meeting

Trails in Information Spaces
My main aim is to gain feedback about a research proposal I'm submitting in a few weeks, titled "Trails in information spaces". I'll be outlining my vision + how I intend to achieve it, and introducing some of the important literature that provides background to the area and the Memories for Life Grand Challenge.

12/10/06
15.30

6.08

Richard Holbrey

Research Group Meeting

A Cure for Scatterplots?
Given a finite amount of room on your screen, there is inevitably a point at which overplotting becomes a problem. Bertini takes one approach, which is to approximate the density of data using user-perception as a guide. After introducing the the paper, this session discusses other attempts to solve the problem using other techniques and tools such as Xmdv, HCE... and my own efforts, using "Eirik".

Notes/Links
Bertini et al., "Give Chance a Chance", InfoVis 2006 (5), 95-110

05/10/06
15.30

6.08

John Hodrien
Jason Wood

Research Group Meeting

Building and Using High Resolution Tiled Displays
The VVR Group (through SRIF funding) has constructed high resolution tiled displays. These are configured as a table with approx 23 million pixels and as a wall with 53 million pixels. While these devices are constructed from standard PC components they cannot be used like a typical PC. This talk will cover the hardware (choice/construction/configuration) of these devices, the range of input devices, available software tools and an example application. It is an opportunity for people to ask questions about how to use them and hopefully provide food for thought on research applications.

25/09/06
12.00

6.08

Alexei Sourin
Nanyang Technological University, Singapore

Research Group Meeting

From a Small Formula to Cyberworlds
The talk covers projects on function-based web visualisation and visualisation on Grid. We have proposed and implemented function-based extensions (FX3D/ FVRML) of X3D and its predecessor VRML which allow for defining time-dependent geometric shapes, their appearance and transformations with analytically defined parametric, implicit and explicit functions. The function-defined shapes can be used together with the standard X3D and VRML shapes. Besides defining shapes by analytical functions, we have developed interactive function-based shape modelling tools. We have extended these interactive shape modelling tools to work on the Grid. We have also developed Grid-based portal for rendering animation scene files. Rendering computer animation frames is a very time consuming job. Using parallel computing on clusters and render farms is a common solution to this problem. In this project we developed a framework for Grid rendering services. We have also developed a novel loseless 3D compression method which allowed us to transfer gigabytes of scene representation files (Renderman (.rib) and mental images (.mi) files).

Summer, 2006

01/09/06
10.00a.m.

6.08

Alfred Inselberg
School of Mathematical Sciences, Tel-Aviv University, Israel

Research Group/VizNet Event

MULTIDIMENSIONAL VISUALIZATION AND ITS APPLICATIONS
Parallel Coordinates Tutorial
The desire to understand the underlying geometry of multivariate (multidimensional) problems, has motivated several visualization methods to augment our limited 3-Dimensional perception. After a short overview, Parallel Coordinates are introduced and rigorously developed obtaining a one-to-one mapping between subsets of N-space and subsets of 2-space. This leads to constructions algorithms in N-space involving intersections, proximity, interior point construction, line and plane Topologies useful in approximations and Computer Vision, as well as Collision Avoidance Algorithms for Air Traffic Control. It is a VISUAL Multidimensional Coordinate system.
Applications to Visual and Automatic Data Mining are illustrated with real multivariate datasets (some with hundreds of variables) together with a Decision Support system capable of doing Feasibility, Trade-Off and Sensitivity Analyses in complex multivariate processes.

Notes/Links
Tutorial Details and Lecture Notes

10/08/06
15.30

6.08

Rodolfo Allendes

Research Group Meeting

See What's Shaking
This years IEEE Visualization Design Contest, also named "see what's shaking" promotes the design of meaningful scientific visualizations for large earthquake simulation data produced by the terashake initiative. Having this contest as starting point, my work has focused on the production of a visualization, i.e a video file, which could help seismologists answer domain specific questions related to the behaviour of an earthquake in the California area.
Slides - PPT (900k)
Video - AVI (8G)

07/08/06
14.00

Active Learning lab.

Prof. Tim David
Centre for Bioengineering at University of Canterbury

Research Group Meeting

Patient Specific Models of Blood Flow in the Cerebral Vasculature
The circle of Willis (CoW) is a ring-like arterial structure located in the base of the brain and is responsible for the distribution of oxygenated blood throughout the cerebral mass. To investigate the effects of the complex 3D geometry and anatomical variability of the CoW on the cerebral hemodynamics, a technique for generating physiologically accurate models of the CoW has been created using a combination of magnetic resonance data and computer aided design software. A mathematical model of the body's cerebral autoregulation mechanism has been developed and numerous computational fluid dynamics simulations performed to model the hemodynamics in response to changes in afferent blood pressure. Three pathological conditions were explored, namely a complete CoW, a fused Anterior Communicating Artery and a missing Posterior Communicating Artery. While a large dataset has been generated as a result of the simulations, the methodology of the cerebral hemodynamic modelling is proposed with the potential for future clinical application in mind, as a diagnostic tool.

03/08/06
15.30

6.08

David Duke
Chris Rooney
Luke Edwards

Research Group Meeting

1. VMLS:
I recently attended a three-day workshop on Visualization in Medical and Life Sciences, organized by the University of Greifswald. Around 40 visualization people were invited, with a strong representation from the US and Germany. Two invited speakers presented life-sciences perspectives and discussed the need for visualization and end-user issues, with technical presentations then setting out relevant work in volume visualization, user interfaces, graph drawing, and applications. In the session I will attempt to summarize the highlights.

2. Clustered Rendering - Summer Project
I have been looking at ways of improving the efficiency of rendering large volumes of data using Iris Explorer. I have been focusing on splitting up data and rendering it on several machines in the visulisation cluster, then combining the final product locally. I have found issues with efficiency which is what I am currently trying to deal with.

3. Summer Project
A short talk by Luke Edwards on the Project developed as a Summer Intern at VVR.

29/06/06
15.30

6.08

Hamish Carr
University College, Dublin

Research Group Meeting

On histograms and isosurface statistics
We show that histograms represent spatial function distributions with a nearest neighbour interpolation, resulting in systematic under-representation of transitional features of the data, and that isosurface statistics, which use higher quality interpolation, give better representations of the function distribution. We also use our experimentally collected isosurface stats to resolve some questions as to the formal complexity of isosurfaces.

15/06/06
15.30

6.08

Nurul Mohd Noor

Research Group Meeting

Asynchronous Collaborative Visualization
Asynchronous collaboration is where people work together at different time and different place. This is often less intrusive and demanding than synchronous collaboration, and of course is extremely valuable when the distance separation involves major change of time zones. E-mail has been a 'killer' application in this respect. Yet much of collaborative visualization research has concerned synchronous working.

In this talk, I will present a general framework as a medium for asynchronous collaborative visualization. The data model for this framework will be presented in tree form. The history tree will be designed with features that help collaborators to follow the collaborative activities that have been carried out over a period of time and help to extract the dataset needed.

Notes/Links
Dennis P. Groth, "Information Provenance and the Knowledge Rediscovery Problem," iv, pp. 345-351, Eighth International Conference on Information Visualisation (IV'04), 2004.

08/06/06
15.30

6.08

Nadia Boukhelifa

Research Group Meeting

Multiple Views in Visualization
Visualization developers are often faced with the question of whether to create a single representation of their data, or to use multiple views. Multiple representations can be more useful when they are coordinated. Hence, to encourage developers to design multi-view visualization systems, a more flexible framework to coordinate views is needed. In fact, a system survey revealed gaps in coordination research, and that current visualization systems tend to embed coordination in an ad hoc fashion. However, whereas embedded coordinations are more suited to explanatory visualization systems, more flexible coordinations should be designed for exploratory visualization where views may be added dynamically. In this talk I will discuss current techniques for coordinating multiple views in information visualization, describe some of the work I have been doing in Kent to coordinate web search results data (using multiform glyphs), and a more generic coordination framework that I have been working on for my PhD.

25/05/06
15.30

6.08

David Duke

Research Group Meeting

Fine grained visualization pipelines and lazy functional programming
This talk describes recent work by Rita Borgo and myself in collaboration with Colin Runciman and Malcolm Wallace from York. Within the EPSRC "Lazy Polytypic Grid" project we are exploring how new technologies for functional programming can be used as a foundation for grid-enabled visualization. Our first results explore how an apparently well-understood algorithm like marching cubes can be reconstructed in quite a different way using functional abstractions: rather than traversal of a (monolithic) dataset,. a stream-based approach has been developed, that uses demand-driven computation to avoid recomputing interpolants. The talk will introduce lazy functional programming, describe its relevance to visualization and computations on the grid, set out our initial results, and outline future directions.

18/05/06
15.30

6.08

David Duke
John Hodrien
Sean Wang

Research Group Meeting

Report on CoLaB visit to China
A report on the recent visit to China as part of the e-science sister project, CoLaB. The project is a collaboration between Leeds and Beihang in China, and is using visualization as a demonstration of inter-operability of Grid infrastructures in the two countries. Ultimately it may lead to worldwide visualization collaboratories...

11/05/06
15.30

6.08

Ken Brodlie
Richard Holbrey

Research Group Meeting

1. Schoolgirls, football fixtures and high-dimensional visualization
Slides - PPT (600k)
A short talk by Ken Brodlie

2. Query driven Visualization of Large Data Sets
Stockinger et al ( PDF). Introduced by Richard Holbrey.

27/04/06
15.30

6.08

Roy Ruddle

Research Group Meeting

How can models of the process of visualization be used to improve visualization tools?

Notes/Links
"A model for the visualization exploration process"
Jankun-Kelly, T.J.; Kwan-Liu Ma; Gertz, M.
IEEE Visualization, 27 Oct.-1 Nov. 2002 Page(s):323 - 330
Digital Object Identifier 10.1109/VISUAL.2002.1183791

Spring, 2006

23/03/06
15.30

6.08

Norman Murray
University of Salford

Research Group Meeting

An Immersive Assembly and Maintenance Simulation Environment

The talk will outline the development of a virtual environment for constraint based assembly and maintenance task simulation and analysis of mechanical products.

Procedures and environments for realistic component assembly, constraint recognition, automatic disassembly sequence generation, and maintenance review and training are presented.

The simulation of maintenance operations allows for maintenance to be addressed early in the design stages. This reduces unforeseen problems creeping into the design as it progresses through its life cycle, consequently saving both time and money while improving product quality.

16/03/06
15.30

6.08

Mini Workshop

Research Group Meeting

Mini-workshop and demonstrations by various members of the group

Adriano - visual representations of errors in isocontouring.
Marcelo - focus and context volume rendering.
Kan Liu - color models and self-organized mapping for visualization of high dimensional datasets.
Rita - flowlines fluid animation video

Notes/Links
Flowlines fluid animation reel

09/03/06
15.30

6.08

Rita Borgo

Research Group Meeting

Space Filling Curves and their Application to Storage and Retrieval of Multi-Dimensional Data.
In 1878 George Cantor demonstrated that any two finite-dimensional smooth manifold, independently of their dimension, have the same cardinality. The Cantor finding implies, in particular, that the interval [0,1] can be mapped bijectively onto the square [0,1]². In 1879 it was demonstrated that such a bijective mapping is necessarily discontinuous. Dropping the bijectivity condition in 1890 Peano constructed a curve representing a surjective mapping from [0,1] onto [0,1]², i.e. a curve that passes through every point of a two-dimensional region with positive area. Curves with this property are now called Space-Filling Curves or Peano Curves. Space Filling Curves are often used in Computer Science as locality preserving hashing function (i.e. Morton Ordering). In this seminar we will go through the mathematical theory at the base of the construction of a space filling curve and present some of the major results existing in literature regarding the application of these primitives to storage and retrieval of n-dimensional data.

02/03/06
15.30

6.08

Roy Ruddle

Research Group Meeting

Tales of Trails
Trails have played a pivotal role in the way people navigate in the real world for thousands of years, and were proposed as an important aid to navigation in information spaces before the first programmable computers even existed (see Bush's "As we may think", Atlantic Monthly, 1945). I will outline the uses of trails to reduce the physical and cognitive effort involved in navigation, briefly describe some experiments I have run to investigate the effects of trails when people navigate 3D virtual environments (VEs), and then focus on my attempts to design algorithms that automatically process large quantities of raw movement data to extract trails that ar a useful aid to navigation. Potentially, these could be used in VEs, the real world and information spaces.

23/02/06
15.30

6.08

Trevor Dodds

Research Group Meeting

Collaborative Interaction in Virtual Environments
What's missing from collaborative interaction in virtual environments that is present in the real world? This talk will provide an outline of collaborative interaction, giving data visualization and urban planning applications as examples.

I will present a paper prototype for my collaborative virtual environment (CVE) using urban planning as a context. I will present some novel forms of interaction that I intend to implement, and discuss one, 'group dynamics', in more detail.

Group dynamics is a socially driven form of interaction that can be simulated in a CVE. In the real world, we don't communicate or operate as one large group. We divide up tasks, split into subgroups, talk to large numbers of people or create side channels of communication. This can be implemented whilst taking advantage of the fact that real world contraints don't have to apply.

16/02/06
15.30

6.08

Ken Brodlie

Research Group Meeting

Contouring and Isosurfacing with Uncertainty
In the classical visualization techniques of contouring and isosurfacing from gridded data, the fundamental step is to estimate the intersection of the contour line or isosurface with the grid lines - by inverse linear interpolation of the values at the grid points. But what happens if these values are known to have an associated error or uncertainty? The talk will propose a new approach in which - rather than represent the intersection as a 'point' - we represent it as a probability density function. The 2D contouring problem is transformed from isoline extraction to image display of the derived pdf, and the 3D visualization problem is transformed from isosurface extraction of the original data to direct volume rendering of the derived pdf. The work is at an early stage and somewhat speculative, and so audience feedback is important! The work is being done in collaboration with Adriano Lopes who is visiting Leeds in February and March.

09/02/06
15.30

6.08

Ben Hammett
Sharp Research (Oxford)

Research Group Meeting

3D Displays
I shall give a quick introduction to Sharp Laboratories of Europe (SLE), where we sit within the Sharp Corporation, what we do, and where the work that I carry out in the 3D contents team fits within the company. SLE have developed the SmartStereo SDK, a set of protocols that allow the developer to set the amount of depth that they would like the viewer to experience in front of and behind the display. Based on these preferences the SDK adjusts the stereo viewpoints of a scene enabling easier development and more comfortable viewing for the user. I will explain how we use this in the development of our 3D content, as well as giving a quick outline of other projects that we are currently working on.

Notes/Links
IEEE Vis Contest 2006

02/02/06
15.30

6.08

David Duke

Research Group Meeting

Inference and Visualization
(slides - PDF 300K)
What is visualization? Answers to this question usually involve words such as understanding, perception, insight, data, and pictures. Taxonomies and ontologies have been used to at tease out what people believe are important components. Nether the less, there seems to be a big gap between these generic ideas, and the research into techniques and representations.

This (short) talk is tentative, putting forward a different view of visualization founded on notions of inference: given a set of facts, what kinds of conclusions can be drawn? I will go through three different kinds of inference, and try to explain their relevance to understanding visualization - and in particular, how they abstract away from differences between scientific and information visualization.

Notes/Links
Roy's report from the e-Science Usability Workshop
Usability Roadtrip paper
"White coats and fingerprints: diagnostic reasoning in medicine and investigative methods of fictional detectives."

26/01/06
15.30

6.08

Rita Borgo

Research Group Meeting

Dealing with Massives Volumetric Visualisation: Progressive Algorithms and Data Structures
Projects dealing with massive amounts of data need to carefully consider all aspects of data acquisition, storage, retrieval and navigation. The recent growth in size of large simulation datasets still surpasses the combined advances in hardware infrastructure and processing algorithms for scientific visualization. The cost of storing and visualizing such datasets is prohibitive, so that only one out of every hundred time-steps can be really stored and visualized. To address these issues we propose an elegant and simple to implement framework for performing out-ofcore visualization and view dependent refinement of large volume datasets. We adopt a method for view dependent refinement that relies on longest edge-bisection strategies yet introducing a new method for extending the technique to the field of Volume Visualization while keeping untouched the simplicity of the technique itself. Results in this field are applicable in parallel and distributed computing ranging from cluster of PC's to more complex and expensive architectures.

Winter, 2005

20/12/05
13.00

VVR Christmas Lunch.

08/12/05
15.30

ALL (9.30a)

Jason Wood

Research Group Meeting - Last of 2005

Providing User Interfaces to Distributed Visualization Systems
The eViz project is attempting to create a system to aid users with high performance visualization tasks. It aims to aid the user, if required, in generating a visualization pipeline and then finds suitable software and hardware on which to execute it. To allow the user to interact with these dynamicaly specified piplelines requires some form of user interface. One of the Leeds contributions to this project is to look at providing a flexible user interface framework to control distributed visualization systems.

eViz website

01/12/05
15.30

6.08

Richard Holbrey

Research Group Meeting

Visual Techniques for Astronomy
A review of my efforts to bring together data mining and visualization, and the importance of data handling and dimensional reduction. A useful thing to read anyway is Fodor's "A survey of dimension reduction techniques" (2002). Some of the detail is scant, but there's a whole lot on wikipedia these days.

A survey of dimension reduction techniques

24/11/05
15.30

6.08

Hamish Carr
University College, Dublin

Research Group Meeting

Flexible Isosurface Interfaces to Scalar Volumetric Data
Many scientific and medical domains generate sampled scalar fields representing the spatial distribution of a physical property in a volume of interest. Tools such as isosurfaces and volume rendering have been developed for visualizing these data sets, but often have problems such as visual occlusion when a single test of feature importance is used throughout the data. We present an interface which uses topological analysis of the scalar field to accelerate isosurface rendering and to allow user control over individual isosurface components. We also show how this interface can be adapted to provide topologically local transfer functions for volume rendering.

Hamish is visiting the group all day.

16 - 18/11/05

n/a

Adriano Lopes
Universidade Nova de Lisboa, Portugal

Visiting the group.

16/11/05
Afternoon

Various

(Roy Ruddle)

VVR Open House

14/11/05
All day

n/a

Samara Alzaidis
University of Canterbury,
New Zealand

Visiting the group.

Links
Bioengineering Centre
Modeling arterial blood flow in the brain

03/11/05
15.30

6.08

Marcelo Cohen

Research Group Meeting

Programming the GPU (... and a brief intro to OpenGL SL)
(slides - PDF, 1.4Mb)
This talk covers GPU evolution towards a programming model based on high level shading languages and also presents a brief introduction to the OpenGL Shading Language and the OpenGL 2.0 API for shader development.

27/10/05
15.30

6.08

Trevor Dodds

Research Group Meeting

Collaborative Interaction in Virtual Environments
Collaborative virtual environments (CVEs) are three dimensional electronic worlds that make use of social simulations (avatars and communication) and shared information (e.g. 3D design models). CVEs use distributed (networked) systems, and often have users in separate locations that need to access remote resources.
The aim of our research is to develop methods that allow users to interact as easily in CVEs as they do when physically co-located in the real world. The usability issues involved are similar to those encountered in e-Science topics where information is shared visually in real time.

Notes/Links
Open Croquet (Alan Kay)
Virtual Rehearsals(UCL)
Collaborative VEs (Brazil)

20/10/05
15.30

6.08

James Handley

Research Group Meeting

Multivariate Visualization of Cardiac Virtual Tissue
This problem has arisen in the e-science Integrative Biology project where biologists are studying the electrical behaviour of cardiac tissue - but is widely applicable. The results of a cardiac simulation are a number of variables (such as voltage, ion concentration, etc), measured across a 2D slice, and where these variables change over time. So we might have a dozen variables, over a 256x256 grid, over 1000 time steps. What is the best way to present this information?

13/10/05
15.30

6.08

David Duke

Research Group Meeting

What Drawing Trees tells us about Visualization, by Pat Hanrahan (slides)
At InfoVis 2001 Pat Hanrahan (Stanford) gave a keynote talk on "How to Draw a Tree". Apart from being a wonderfully entertaining talk, the exploration of an apparently narrow topic - tree drawing - throws up a number of fundamental questions in visualization. One of these, the relationship between external and internal representations, is one we have all probably encountered. But two further issues are possibly less familiar: the need to mix metaphors, and the importance of aesthetics in depiction.
In the session, I will go through the talk that Pat Hanrahan gave, but without of course the benefit of his experience and knowledge!

06/10/05
15.30

6.08

Ken Brodlie

Research Group Meeting

10 Unsolved Problems in Information Visualization, by Chaomei Chen. PDF

Notes/Links
Kosara et al User Studies paper
Edward Tufte web site
Chris Johnson's unsolved problems
Informatics MSc student papers on evaluating vis
The Value of Visualization, Jarke J. van Wilk. IEEE Vis Oct 2005.

Visualization and Virtual Reality Group School of Computing, University of Leeds
		VVR Group Events (archive)

VVR Group Events (archive)