Technical University of Berlin

About: Technical University of Berlin is a education organization based out in Berlin, Germany. It is known for research contribution in the topics: Quantum dot & Laser. The organization has 27292 authors who have published 59342 publications receiving 1414623 citations. The organization is also known as: Technische Universität Berlin & TU Berlin.

Sketch-based shape retrieval

Abstract: We develop a system for 3D object retrieval based on sketched feature lines as input. For objective evaluation, we collect a large number of query sketches from human users that are related to an existing data base of objects. The sketches turn out to be generally quite abstract with large local and global deviations from the original shape. Based on this observation, we decide to use a bag-of-features approach over computer generated line drawings of the objects. We develop a targeted feature transform based on Gabor filters for this system. We can show objectively that this transform is better suited than other approaches from the literature developed for similar tasks. Moreover, we demonstrate how to optimize the parameters of our, as well as other approaches, based on the gathered sketches. In the resulting comparison, our approach is significantly better than any other system described so far.

Aspects of Nucleophilic Carbene Chemistry

Abstract: Bis [1,3-diphenyl-2-imidazolidinylidene]- shows a considerable tendency towards dissociation into two carbenes. Reactions with this easily accessible carbene source lead to an understanding of nucleophilic carbene chemistry. The question of the existence of particularly stable carbenes is discussed, and it is suggested that a surprisingly large area of preparative possibilities and theoretical knowledge awaits development.

Power-saving mechanisms in emerging standards for wireless LANs: the MAC level perspective

Abstract: This article provides an overview of mechanisms used for power saving in the upcoming standards for wireless LANs: IEEE 80211 and ETSI RES 10 HIPERLAN Power saving on the MAC level is addressed by these standards in a quite different way We outline the main features of the mechanisms in both standards in terms of power saving In addition we present simulation studies of the power-saving mechanism in ad hoc configurations of IEEE 80211 networks, which demonstrate the optimization potential and some performance trade-offs quantitatively

Heat pulse experiments revisited

Abstract: This is a review of heat propagation — theory and experiment — in dielectric solids at low temperatures where the phenomenon of second sound occurs. The review does not merely present a list of the various explanations of the observed phenomena. Rather it views them as special cases of a unified theory which is formulated within the framework of extended thermodynamics of phonos. Field equations are derived by averaging over the phonon-Boltzmann equation and initial and boundary value problems are solved. Thus it became possible to achieve a full explanation of the observations of the heat-pulse experiments in which ballistic phonons, second sound and ordinary heat conduction compete.