Helmuth Trefftz

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The availability of inexpensive and powerful graphics cards as well as fast Internet connections make Networked Virtual Environments viable for millions of users and many new applications. It is therefore necessary to cope with the growing heterogeneity that arises from differences in computing power, network speed and users’ preferences. This paper(More)
We propose a communication’s architecture for scaling distributed environments, aimed at minimizing the number of required multicast groups. The fundamental idea is to approximate the area-of-interest of entities, which ideally would be round, with hexagonal cells, and then associate multicast groups to the cells only when necessary – i.e. when the discrete(More)
In this paper we explore to what degree shared viewpoints in three-dimensional collaborative virtual environments enable effective collaboration. The paper applies research on shared viewpoints and telepointers to 3D environments. A lightweight Java-based tool for creating collaborative virtual environments was developed and used in the study. The system is(More)
This article presents the first results of using an Augmented Reality (AR) tool, designed to support tutoring sessions in multi-variate calculus. The tool is used either in a face-to-face setting in which the instructor and the students are collocated or in a distance setting, in which the instructor and students are physically in remote places. The tool(More)
In actual applications of virtual environments, one of the problems that has received attention is the way to assign computational resources to those who participate in the system. In most cases, static resource allocation is used. Static allocation is simple but has several limitations, among them, the missutilization of resources. In this paper we present(More)
The use of Shared Virtual Environments is growing in areas such as multi-player video games, military and industrial training, and collaborative design and engineering. As a result, different mixes of computing power and graphics capabilities of the participating computers arise naturally as the variety of people/organizations sharing a virtual environment(More)
In this paper we report results of the use of a telepresence application in a simulated distance education setting. The application combines video-conference with a networked virtual environment in which the instructor and the students can experiment with virtual object in a collaborative manner. The teaching for Understanding (TFU) framework is used as the(More)
The recent advances in the fields such as modeling bio-mechanics of living tissues, haptic technologies, computational capacity, and virtual environments have created conditions necessary in order to develop effective surgical training and learning methods. Simulation environments for surgical training have no limitations on the number of times a procedure(More)
Recent advances in fields such as modeling of deformable objects, haptic technologies, immersive technologies, computation capacity and virtual environments have created the conditions to offer novel and suitable training tools and learning methods in the medical area. One of these training tools is the virtual surgical simulator, which has no limitations(More)