Vienna University of Technology

About: Vienna University of Technology is a education organization based out in Vienna, Austria. It is known for research contribution in the topics: Laser & Cloud computing. The organization has 16723 authors who have published 49341 publications receiving 1302168 citations.

Interactive visual editing of grammars for procedural architecture

Abstract: We introduce a real-time interactive visual editing paradigm for shape grammars, allowing the creation of rulebases from scratch without text file editing. In previous work, shape-grammar based procedural techniques were successfully applied to the creation of architectural models. However, those methods are text based, and may therefore be difficult to use for artists with little computer science background. Therefore the goal was to enable a visual work-flow combining the power of shape grammars with traditional modeling techniques. We extend previous shape grammar approaches by providing direct and persistent local control over the generated instances, avoiding the combinatorial explosion of grammar rules for modifications that should not affect all instances. The resulting visual editor is flexible: All elements of a complex state-of-the-art grammar can be created and modified visually.

A survey on self-healing systems: approaches and systems

Abstract: Present large-scale information technology environments are complex, heterogeneous compositions often affected by unpredictable behavior and poor manageability. This fostered substantial research on designs and techniques that enhance these systems with an autonomous behavior. In this survey, we focus on the self-healing branch of the research and give an overview of the current existing approaches. The survey is introduced by an outline of the origins of self-healing. Based on the principles of autonomic computing and self-adapting system research, we identify self-healing systems’ fundamental principles. The extracted principles support our analysis of the collected approaches. In a final discussion, we summarize the approaches’ common and individual characteristics. A comprehensive tabular overview of the researched material concludes the survey.

Spin-3 Gravity in Three-Dimensional Flat Space

Abstract: We present the first example of a nontrivial higher spin theory in three-dimensional flat space. We propose flat-space boundary conditions and prove their consistency for this theory. We find that the asymptotic symmetry algebra is a (centrally extended) higher spin generalization of the Bondi-Metzner-Sachs algebra, which we describe in detail. We also address higher spin analogues of flat space cosmology solutions and possible generalizations.

Bayesian-multiplicative treatment of count zeros in compositional data sets

Abstract: This research was supported by the Ministerio de Economia y Competividad under the project 'METRICS' Ref. MTM2012-33236, by the Agencia de Gestio d'Ajuts Universitaris i de Recerca of the Generalitat de Catalunya under the project Ref: 2009SGR424, and by the Scottish Government's Rural and Environment Science and Analytical Services Division (RESAS). The authors also gratefully acknowledge the support by the Operational Program Education for Competitiveness-European Social Fund (project CZ.1.07/2.3.00/20.0170 of the Ministry of Education, Youth and Sports of the Czech Republic)

A novel dual circulating fluidized bed system for chemical looping processes

Abstract: A fluidized bed system combining two circulating fluidized bed reactors is proposed and investigated for chemical looping combustion. Direct hydraulic communication of the two circulating fluidized bed reactors via a fluidized loop seal allows for high rates of global solids circulation and results in a stable solids distribution in the system. A 120 kW fuel power bench scale unit was designed, built, and operated. Experimental results are presented for natural gas as fuel using a nickel-based oxygen carrier. No carbon was lost to the air reactor under any conditions operated. It is shown from fuel power variations that a turbulent/fast fluidized bed regime in the fuel reactor is advantageous. Despite the relatively low riser heights (air reactor: 4.1 m, fuel reactor: 3.0 m), high CH4 conversion and CO2 yield of up to 98% and 94%, respectively, can be reported for the material tested. © 2009 American Institute of Chemical Engineers AIChE J, 2009