Bauhaus University, Weimar

About: Bauhaus University, Weimar is a education organization based out in Weimar, Thüringen, Germany. It is known for research contribution in the topics: Finite element method & Isogeometric analysis. The organization has 1421 authors who have published 2998 publications receiving 104454 citations. The organization is also known as: Bauhaus-Universität Weimar & Hochschule für Architektur und Bauwesen.

Occlusion shadows: using projected light to generate realistic occlusion effects for view-dependent optical see-through displays

Abstract: This paper presents projector-based illumination techniques for creating correct occlusion effects for optical see-through setups. We project view-dependent occlusion shadows onto the real surfaces that are located behind virtual objects. This results in a perfect occlusion of real objects by virtual ones. We have implemented and tested our approach in the context of the Virtual Showcase display. We describe a hardware extension for projecting light into the showcase and present our rendering techniques for displaying occlusion shadows for single and multi-user environments as well as for single and multi-light-projector configurations. We also report on the limitations of our system for multi-user situations and describe our experiences with a first experimental prototype.

On the numerical stability and mass-lumping schemes for explicit enriched meshfree methods

Abstract: SUMMARY Meshfree methods (MMs) such as the element free Galerkin (EFG)method have gained popularity because of some advantages over other numerical methods such as the finite element method (FEM). A group of problems that have attracted a great deal of attention from the EFG method community includes the treatment of large deformations and dealing with strong discontinuities such as cracks. One efficient solution to model cracks is adding special enrichment functions to the standard shape functions such as extended FEM, within the FEM context, and the cracking particles method, based on EFG method. It is well known that explicit time integration in dynamic applications is conditionally stable. Furthermore, in enriched methods, the critical time step may tend to very small values leading to computationally expensive simulations. In this work, we study the stability of enriched MMs and propose two mass-lumping strategies. Then we show that the critical time step for enriched MMs based on lumped mass matrices is of the same order as the critical time step of MMs without enrichment. Moreover, we show that, in contrast to extended FEM, even with a consistent mass matrix, the critical time step does not vanish even when the crack directly crosses a node. Copyright © 2011 John Wiley & Sons, Ltd.

A Review Corpus for Argumentation Analysis

Abstract: The analysis of user reviews has become critical in research and industry, as user reviews increasingly impact the reputation of products and services. Many review texts comprise an involved argumentation with facts and opinions on different product features or aspects. Therefore, classifying sentiment polarity does not suffice to capture a review's impact. We claim that an argumentation analysis is needed, including opinion summarization, sentiment score prediction, and others. Since existing language resources to drive such research are missing, we have designed the ArguAna TripAdvisor corpus, which compiles 2,100 manually annotated hotel reviews balanced with respect to the reviews' sentiment scores. Each review text is segmented into facts, positive, and negative opinions, while all hotel aspects and amenities are marked. In this paper, we present the design and a first study of the corpus. We reveal patterns of local sentiment that correlate with sentiment scores, thereby defining a promising starting point for an effective argumentation analysis.

3D User Interfaces

Abstract: The articles in this special issue present recent developments in research on 3D user interfaces. Topics covered include reality- and imagination-based interaction, pointing techniques, analysis of rapid aimed movements, temporal-data visualizations, and navigation of augmented CAD models.