Technische Universität Darmstadt

About: Technische Universität Darmstadt is a education organization based out in Darmstadt, Germany. It is known for research contribution in the topics: Neutron & Finite element method. The organization has 17316 authors who have published 40619 publications receiving 937916 citations. The organization is also known as: Darmstadt University of Technology & University of Darmstadt.

Non-collinear antiferromagnets and the anomalous Hall effect

Abstract: The anomalous Hall effect is investigated theoretically by employing density functional calculations for the non-collinear antiferromagnetic order of the hexagonal compounds Mn3Ge and Mn3Sn using various planar triangular magnetic configurations as well as unexpected non-planar configurations. The former give rise to anomalous Hall conductivities (AHC) that are found to be extremely anisotropic. For the planar cases the AHC is connected with Weyl points in the energy-band structure. If this case were observable in Mn3Ge, a large AHC of about should be expected. However, in Mn3Ge it is the non-planar configuration that is energetically favored, in which case it gives rise to an AHC of . The non-planar configuration allows a quantitative evaluation of the topological Hall effect that is seen to determine this value of to a large extent. For Mn3Sn it is the planar configurations that are predicted to be observable. In this case the AHC can be as large as .

Multiple Object Class Detection with a Generative Model

Abstract: In this paper we propose an approach capable of simultaneous recognition and localization of multiple object classes using a generative model. A novel hierarchical representation allows to represent individual images as well as various objects classes in a single, scale and rotation invariant model. The recognition method is based on a codebook representation where appearance clusters built from edge based features are shared among several object classes. A probabilistic model allows for reliable detection of various objects in the same image. The approach is highly efficient due to fast clustering and matching methods capable of dealing with millions of high dimensional features. The system shows excellent performance on several object categories over a wide range of scales, in-plane rotations, background clutter, and partial occlusions. The performance of the proposed multi-object class detection approach is competitive to state of the art approaches dedicated to a single object class recognition problem.

Flexible and fine-grained mandatory access control on Android for diverse security and privacy policies

Abstract: In this paper we tackle the challenge of providing a generic security architecture for the Android OS that can serve as a flexible and effective ecosystem to instantiate different security solutions In contrast to prior work our security architecture, termed FlaskDroid, provides mandatory access control simultaneously on both Android's middleware and kernel layers The alignment of policy enforcement on these two layers is non-trivial due to their completely different semantics We present an efficient policy language (inspired by SELinux) tailored to the specifics of Android's middleware semantics We show the flexibility of our architecture by policy-driven instantiations of selected security models such as the existing work Saint as well as a new privacy-protecting, user-defined and fine-grained per-app access control model Other possible instantiations include phone booth mode, or dual persona phone Finally we evaluate our implementation on SE Android 404 illustrating its efficiency and effectiveness

O'Mega: An Optimizing Matrix Element Generator

Abstract: I sketch the architecture of O'Mega, a new optimizing compiler for tree amplitudes in quantum field theory. O'Mega generates the most efficient code currently available for scattering amplitudes for many polarized particles in the standard model. A complete infrastructure for physics beyond the standard model is provided.

AO4BPEL: An Aspect-oriented Extension to BPEL

Abstract: Process-oriented composition languages such as BPEL allow Web Services to be composed into more sophisticated services using a workflow process. However, such languages exhibit some limitations with respect to modularity and flexibility. They do not provide means for a well-modularized specification of crosscutting concerns such as logging, persistence, auditing, and security. They also do not support the dynamic adaptation of composition at runtime. In this paper, we advocate an aspect-oriented approach to Web Service composition and present the design and implementation of AO4BPEL, an aspect-oriented extension to BPEL. We illustrate through examples how AO4BPEL makes the composition specification more modular and the composition itself more flexible and adaptable.