E.M.A.G. van Dijk

CONTROLLING THE GAZE OF CONVERSATIONAL AGENTS

We report on a pilot experiment that investigated the effects of different eye gaze behaviours of a cartoon-like talking face on the quality of human-agent dialogues. We compared a version of the talking face that roughly implements some patterns of human-like behaviour with two other versions. In one of the other versions the shifts in gaze were kept minimal and in the other version the shifts would occur randomly. The talking face has a number of restrictions. There is no speech recognition, so questions and replies have to be typed in by the users of the systems. Despite this restriction we found that participants that conversed with the agent that behaved according to the human-like patterns appreciated the agent better than participants that conversed with the other agents. Conversations with the optimal version also proceeded more efficiently. Participants needed less time to complete their task.

Applying a User-centred Approach to Interactive Visualization Design

Analysing users in their context of work and finding out how and why they use different information resources is essential to provide interactive visualisation systems that match their goals and needs. Designers should actively involve the intended users throughout the whole process. This chapter presents a user-centered approach for the design of interactive visualisation systems. We describe three phases of the iterative visualisation design process: the early envisioning phase, the global specification hase, and the detailed specification phase. The whole design cycle is repeated until some criterion of success is reached. We discuss different techniques for the analysis of users, their tasks and domain. Subsequently, the design of prototypes and evaluation methods in visualisation practice are presented. Finally, we discuss the practical challenges in design and evaluation of collaborative visualisation environments. Our own case studies and those of others are used throughout the whole chapter to illustrate various approaches.

Bringing hollywood to the driving school: dynamic scenario generation in simulations and games

In this paper we discuss a framework for simulation software called the movie metaphor. It is applied to the Dutch Driving Simulator for dynamic control of traffic scenarios. This framework resolves software complexity by the use of agent protocols inspired by the way of working on a movie set. It defines clear responsibilities for the agents so that the system is extensible, maintainable and easy to understand. The framework is a software pattern for multiagent systems especially suitable for simulation software and games.

Interactive navigation of segmented MR angiograms using simultaneous curved planar and volume visualizations

PurposeInteractive visualization is required to inspect and monitor the automatic segmentation of vessels derived from contrast-enhanced magnetic resonance angiography (CE-MRA). A dual-view visualization scheme consisting of curved planar reformation (CPR) and direct volume rendering (DVR) was developed for this purpose and tested.MethodsA dual view visualization scheme was developed using the vessel pathline for both camera position and rotation in 3D, greatly reducing the degrees of freedom (DOF) required for navigation. Pathline-based navigation facilitates coupling of the CPR and DVR views, as local position and orientation can be matched precisely. The new technique was compared to traditional techniques in a user study. Layperson users were required to perform a visual search task that involves checking for (minor) errors in segmentations of MRA data from a software phantom. The task requires the user to examine both views.ResultsPathline-based navigation and coupling of CPR and DVR provide user speed performance improvements in a vessel inspection task. Interactive MRA visualization with this method, where rotational degrees of freedom were reduced, had no negative effect.ConclusionsThe DOF reduction achieved by the new navigation technique is beneficial to user performance. The technique is promising and merits comprehensive evaluation in a realistic clinical setting.

Use and misuse of taxonomies of learning: integrated educational goals in computer science curricula

Most systematic design procedures for either curricula or courses start from a description of educational goals. These goals are then decomposed into more specific objectives which are categorized according to some taxonomy of learning. The basic idea is that different categories of goals and objectives correspond with different optimal instructional methods. However, for complex intellectual skills a set of subskills is performed. The ability to perform each of those subskills separately does not guarantee that the skills can be coordinated and integrated in performing real-world tasks. This problem is known as the problem of ‘integrated goals’ or ‘multiple objectives’. This paper argues that educational goals and objectives should be seen and treated as highly integrated and interrelated during the whole educational design process. Approaches to dealing with multiple objectives are discussed.