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Xface, the new version of our open source, platform independent toolkit for developing 3D embodied conversational agents is presented. The toolkit currently incorporates four pieces of software. The core Xface library is for developers who want to embed 3D facial animation to their applications. XfaceEd editor provides an easy to use interface to generate MPEG-4 ready meshes from static 3D models. XfacePlayer is a sample application that demonstrates the toolkit in action and XfaceClient is used as the communication controller over network. [ABSTRACT FROM AUTHOR]

Bayesian nets (BNs) appeared in the 1980s as a solution to computational and representational problems encountered in knowledge representation of uncertain information. Shortly afterwards, BNs became an important part of the AI mainstream. During the 1990s, a lively discussion emerged regarding the causal semantics of Bayesian nets, challenging almost a century of statistical orthodoxy regarding inference of causal relations from observational data, and many refer to BNs now as causal graphs. However, the discussion of causal graphs as a data visualization tool has been limited. We argue here that causal graphs together with their causal semantics for seeing and setting, have the potential to be as powerful and generic a data visualization tool as line graphs or pie charts. [ABSTRACT FROM AUTHOR]

Developments in basic neurological research and techniques used to train professional athletes suggest that one way of facilitating this learning process of motor schemas is through the use of motor imagery, a training technique in which the procedure required to perform a task is mentally rehearsed in absence of actual physical movement. Clinical studies have shown that rehabilitation of hemiplegic and hemiparetic patients can be improved by integrating physical and mental practice. In this paper, we describe an advanced virtual reality workbench, the VR- Mirror, that it has been designed to support stroke patients with upper-limb hemiplegia in generating motor images. The development of this prototype has been supported by the Commission of the European Communities (CEC) - IST programme (Project I-Learning, IST 2001-38861). [ABSTRACT FROM AUTHOR]

Computer-assisted animation production tools have an important role in animation production industries. They could reduce the production cost and time. In this paper, a new computer-assisted artistic pattern drawing system is proposed. The system automatically adds artistic patterns to 2D animations. The artistic patters are captured from key frames drawn by an animator and are applied to line drawings. The result shows that the presented approach can copy artistic patterns from key frames and reduce time and cost for producing artistic animations. [ABSTRACT FROM AUTHOR]

In the field of the architectural heritage, the representation of artefacts, particularly for communication purposes, has benefited from the development of computer-based modelling techniques in fields ranging form archaeology to geography. But numerous experts in the above mentioned heritage field have come to question the readability of realistic models inside which the hypothetical nature of the content, a reconstruction, is not clearly assessed. In parallel, research in information visualisation has demonstrated that graphics can support reasoning as well as communication. Our contribution introduces the genesis of an informative modelling methodology in which the representation of architectural objects is used for information search and visualisation. 3D or 2D models localise objects in time, in space, and in a hierarchy of canonical shapes; they are calculated on the fly and deliver information visually. This paper discusses the underlying modelling methodology and applications in investigations about the evolutions of the city of Kraków (Poland). [ABSTRACT FROM AUTHOR]

3d visualisation of real spaces in the Internet is nowadays getting ready for all day usage. Because of higher complexity of 3d- compared to 2d visualisation, it is mostly used for high-end visualisations. The strategy of integrating them into existing spatial data infrastructures and making reuse of existing resources that are so far mostly used for 2d visualisation, created the opportunity to build 3d web-applications as an add-on. The recurring problems of web-based 3d visualisation raised the question, how special modules for 3d visualisation could also be made reuseable. We took a closer look especially on the so-called mapping-level, which is essential for the type of visualisation, interactivity and some special analysis-tasks. [ABSTRACT FROM AUTHOR]

We describe our current work on volume visualization techniques developed with the aim to enhance interactive exploration of medical datasets. Volumetric lenses can be applied to a volume dataset to interactively focus regions of interest within these datasets. During rendering the parts of a volume dataset intersecting the lens, which is defined by a convex 3D shape, are rendered using a different visual appearance. The lenses proposed allow to apply non-photorealistic rendering techniques interactively to aid comprehension for medical diagnosis. [ABSTRACT FROM AUTHOR]

Indirect and unintuitive commands like mode-switching are difficult operations for many users. In this paper, we describe a new simple interface for a 2D drawing system to lessen user's confusion. Firstly, we propose a direct manipulation interface based on a set of geometric primitives and their geometric relationships. Secondly, we present a seamless drawing interface that users do not need to switch modes by clicking the toolbar. Through user tests using our prototypes and a standard commercial application, we confirmed that our system can complete certain drawing tasks with shorter completion time and less number of commands. [ABSTRACT FROM AUTHOR]

This work focuses on interface design for supporting users of instrumented environments to interact with virtual information embedded in the real world. A gesture-based interaction paradigm is presented and the prototype of an interface providing affordances for gesture-based direct manipulation of digital information is described. [ABSTRACT FROM AUTHOR]

Large horizontal displays provide new opportunities to support individual and collaborative activities such as creativity and organizational tasks. We present Interface Currents, a fluid interaction technique designed to support face-to-face collaboration by improving access to and sharing of workspace items. Interface Currents are flexible containers that provide a controllable flow of interface items that support creativity during collaborative tasks and enable intuitive organization and sharing of digital information around horizontal displays. [ABSTRACT FROM AUTHOR]

Cross-sectioning is a popular method for visualizing the complicated inner structures of three-dimensional volume datasets. However, the process is usually manual, meaning that a user must manually specify the cross-section's location using a repeated trial-and-error process. To find the best cross-sections, this method requires that a user is knowledgeable and experienced. This paper proposes a method for automatically generating characteristic cross-sections from a given volume dataset. The application of a volume skeleton tree (VST), which is a graph that delineates the topological structure of a three-dimensional volume, facilitates the automated generation of cross-sections giving good representations of the topological characteristics of a dataset. The feasibility of the proposed method is demonstrated using several examples. [ABSTRACT FROM AUTHOR]

Shading has a great impact to the human perception of 3D objects. Thus, in order to create or to deform a 3D object, it seems natural to manipulate its perceived shading. This paper presents a new solution for the software implementation of this idea. Our approach is based on the ability of a user to coarsely draw a shading, under different lighting directions. With this intuitive process, users can create or edit a height field (locally or globally), that will correspond to the drawn shading values. Moreover, we present the possibility to edit the shading intensity by means of a specular reflectance model. Keywords: Shape Modeling, Image Based Modeling, Shape From Shading. [ABSTRACT FROM AUTHOR]

Parametric design systems model a design as a constrained collection of schemata. Designers work in such systems at two levels: definition of schemata and constraints; and search within a schema collection for meaningful instances. Propagation-based systems yield efficient algorithms that are complete within their domain, require explicit specification of a directed acyclic constraint graph and allow relatively simple debugging strategies based on antecedents and consequents. The requirement to order constraints appears to be useful in expressing specific designer intentions and in disambiguating interaction. A key feature of such systems in practice appears to be a need for multiple views onto the constraint model and simultaneous interaction across views. We describe one multiple-view structure, its development and refinement through a large group of architecture practitioners and its realization in the system Generative Components. [ABSTRACT FROM AUTHOR]

Due to the progress in computer graphics hardware high resolution 3d models may be explored at interactive frame rates, and facilities to explore them are a part of modern radiological workstations and therapy planning systems. Despite their advantages, 3d visualizations are only employed by a minority of potential users and even these employ 3d visualizations for a few selected tasks only. We hypothesize that this results from a lack of intuitive interaction techniques for 3d rotation. In this paper, we compare existing techniques with respect to design principles derived by clinical applications and present results of an empirical study. These results are relevant beyond clinical applications and strongly suggest that the presented design principles are crucial for comfortable and predictable interaction techniques for 3d rotation. [ABSTRACT FROM AUTHOR]

This paper presents a smart algorithm for labeling column charts and their derivatives. To efficiently solve the problem, we separate it into two sub-problems. We first present a geometric algorithm to solve the problem of finding a good labeling for the labels of a single column, given that some other columns have already been labeled. We then present a strategy for finding a good order in which columns should be labeled, which repeatedly uses the first algorithm for some limited look-ahead. The presented algorithm is being used in a commercial product to label charts, and has shown in practice to produce satisfactory results. [ABSTRACT FROM AUTHOR]

Co-referential relations between textual and visual elements in illustrations can be encoded efficiently through textual labels. The labels support students to learn unknown terms and focus their attention on important aspects of the illustration; while a functional and aesthetic label layout aims at guaranteeing the readability of text strokes as well as preventing the referential mismatches. By analyzing a corpus of complex label layouts in hand-drawn illustrations, a classification of label layout styles and several metrics for functional requirements and aesthetic attributes were extracted. As the choice of a specific layout style seems largely determined by individual preferences, a real-time layout algorithm for internal and external labels balances conflicting user-specific requirements, functional and aesthetic attributes. [ABSTRACT FROM AUTHOR]

We present a system using semi-autonomous agents to help artists express ideas. Agents control their representation on a canvas via interactions in agent space. They are given rules, which include the ability to form, join, leave and dissolve coalitions. While individually, agents constitute only small parts of the composition, together they form more and more complex parts until the full picture emerges. The artist can take direct control of an agent or coalition if the result is unsatisfactory. We have implemented the Surreal engine that realises these ideas and we present a case study of its usage in producing Mondriaan-like paintings. [ABSTRACT FROM AUTHOR]

We present a method to generate glyphs which convey complex information in graphical form. A glyph has a linear geometry which is specified using geometric operations, each represented by characters nested in a string. This format allows several glyph strings to be concatenated, resulting in more complex geometries. We explore automatic generation of a large number of glyphs using a genetic algorithm. To measure the visual distinctness between two glyph geometries, we use the iterative closest point algorithm. We apply these methods to create two different types of representations for biological proteins, transforming the rich data describing their various characteristics into graphical form. The representations are automatically built from a finite set of glyphs, which have been created manually or using the genetic algorithm. [ABSTRACT FROM AUTHOR]

The article discusses an application of the Representational Epistemology (REEP) approach to the development of a graphical interface for production planning and scheduling called ROLLOUT. The paper reports two studies conducted with bakery planning and scheduling professionals that focus on the cognitive support provided by ROLLOUT in reasoning about the spatial-temporal structure of production processes. The results of the first task suggest that given tabular representations, participants frequently make errors in decisions about the assignment of production sequences in terms of their temporal structure. The errors are more frequent for problems that require reasoning about consequences backwards rather than forwards in time. The second task evaluated participants' performance at improving production schedules on ROLLOUT. Log files revealed that participants improved the temporal efficiency of the schedule by making edit operations involving frequent repetitions with the same instances that tended to change the time and not the order of production. The authors propose that participants were able to effectively use ROLLOUT to generate an efficient schedule at increasing levels of precision by using the representation to test out and re-evaluate concurrent what-if scenarios. The advantages of ROLLOUT for such tasks are explained in terms of (1) the presence of diagrammatic constraints that preserve domain relations, (2) the presence of a global interpretive scheme, and (3) the degree of meaningful conceptual interrelations available in the representation. [ABSTRACT FROM AUTHOR]

In this paper we tackle the main problem presented by the majority of Information Visualization techniques, that is, the limited number of data items that can be visualized simultaneously. Our approach proposes an innovative and interactive systematization that can augment the potential for data presentation by utilizing multiple views. These multiple presentation views are kept linked according to the analytical decisions took by the user and are tracked in a tree-like structure. Our emphasis is on developing an intuitive yet powerful system that helps the user to browse the information and to make decisions based both on overview and on detailed perspectives of the data under analysis. The visualization tree keeps track of the interactive actions taken by the user without losing context. [ABSTRACT FROM AUTHOR]

This paper describes the process by which we have constructed an adaptive system for external representation (ER) selection support, designed to enhance users' ER reasoning performance. We describe how our user model has been constructed - it is a Bayesian network with values seeded from data derived from experimental studies. The studies examined the effects of users' background knowledge-of-external representations (KER) upon performance and their preferences for particular information display forms across a range of database query types. [ABSTRACT FROM AUTHOR]

Modelling, animation and rendering has dominated research computer graphics yielding increasingly rich and realistic virtual worlds. The complexity, richness and quality of the virtual worlds are viewed through a single media that is a virtual camera. In order to properly convey information, whether related to the characters in a scene, the aesthetics of the composition or the emotional impact of the lighting, particular attention must be given to how the camera is positioned and moved. This paper presents an overview of automated camera planning techniques. After analyzing the requirements with respect to shot properties, we review the solution techniques and present a broad classification of existing approaches. We identify the principal shortcomings of existing techniques and propose a set of objectives for research into automated camera planning. [ABSTRACT FROM AUTHOR]

This article describes the integration of knowledge based techniques into simulative Virtual Reality (VR) applications. The approach is motivated using multimodal Virtual Construction as an example domain. An abstract Knowledge Representation Layer (KRL) is proposed which is expressive enough to define all necessary data for diverse simulation tasks and which additionally provides a base formalism for the integration of Artificial Intelligence (AI) representations. The KRL supports two different implementation methods. The first method uses XSLT processing to transform the external KRL format into the representation formats of the diverse target systems. The second method implements the KRL using a functionally extendable semantic network. The semantic net library is tailored for real time simulation systems where it interconnects the required simulation modules and establishes access to the knowledge representations inside the simulation loop. The KRL promotes a novel object model for simulated objects called Semantic Entities which provides a uniform access to the KRL and which allows extensive system modularization. The KRL approach is demonstrated in two simulation areas. First, a generalized scene graph representation is presented which introduces an abstract definition and implementation of geometric node interrelations. It supports scene and application structures which can not be expressed using common scene hierarchies or field route concepts. Second, the KRL's expressiveness is demonstrated in the design of multimodal interactions. Here, the KRL defines the knowledge particularly required during the semantic analysis of multimodal user utterances. [ABSTRACT FROM AUTHOR]

We describe an immersive music visualization application which enables interaction between a live musician and a responsive virtual character. The character reacts to live performance in such a way that it appears to be experiencing an emotional response to the music it ‘hears.' We modify an existing tonal music encoding strategy in order to define how the character perceives and organizes musical information. We reference existing research correlating musical structures and composers' emotional intention in order to simulate cognitive processes capable of inferring emotional meaning from music. The ANIMUS framework is used to define a synthetic character who visualizes its perception and cognition of musical input by exhibiting responsive behaviour expressed through animation. [ABSTRACT FROM AUTHOR]

During the last decade research groups as well as a number of commercial software developers have started to deploy embodied conversational characters in the user interface especially in those application areas where a close emulation of multimodal human-human communication is needed. Most of these characters have one thing in common: In order to enter the user's physical world, they need to be physical themselves. The paper focuses on challenges that arise when embedding synthetic conversational agents in the user's physical world. We will start from work on synthetic agents that populate virtual worlds and anthropomorphic robots that inhabit physical worlds and discuss how the two areas need to be combined in order to populate physical worlds with synthetic characters. Finally, we will report on so-called traversable interfaces that allow agents to cross the border from the physical space to the virtual space and vice versa. [ABSTRACT FROM AUTHOR]

Interactive 3D statistics visualizations have certain limitations. Through experiments with a 3D model, I have created a number of interaction techniques - the Reference Grid, Callouts and Interactive Blending - to address and avoid these limitations. [ABSTRACT FROM AUTHOR]