TiGL - An Open Source Computational Geometry Library for Parametric Aircraft Design

This paper introduces the software TiGL: TiGL is an open source high-fidelity geometry modeler that is used in the conceptual and preliminary aircraft and helicopter design phase. It creates full three-dimensional models of aircraft from their parametric CPACS description. Due to its parametric nature, it is typically used for aircraft design analysis and optimization. First, we present the use-case and architecture of TiGL. Then, we discuss it's geometry module, which is used to generate the B-spline based surfaces of the aircraft. The backbone of TiGL is its surface generator for curve network interpolation, based on Gordon surfaces. One major part of this paper explains the mathematical foundation of Gordon surfaces on B-splines and how we achieve the required curve network compatibility. Finally, TiGL's aircraft component module is introduced, which is used to create the external and internal parts of aircraft, such as wings, flaps, fuselages, engines or structural elements

Kognitive und somatische Komponenten der bewussten Fehlerwahrnehmung

Die bewusste Gewahrwerdung von Fehlern ist eine wichtige Leistung des kognitiven Systems. Die Erforschung der elektrophysiologischen Prozesse, die der Fehlerverarbeitung im menschlichen Gehirn zu Grunde liegen, betraf in den letzten beiden Jahrzehnten vor allem zwei Ereigniskorrelierte Potentiale (EKPs): Die error-related negativity (ERN) und die error positivity (Pe). Beide Potentiale lassen sich im Skalp-EEG nach fehlerhaften Handlungen in vielerlei Kontext beobachten, ihre Rolle (im Besonderen die der ERN) bei der bewussten Gewahrwerdung von Handlungsfehlern ist jedoch bisher unklar. Die vorliegende Arbeit zeigt durch Vergleich von bewusst wahrgenommenen zu nicht bewusst wahrgenommenen Fehlern bei menschlichen Probanden, dass die Amplitude der ERN sich nicht nur in Abhaengigkeit der subjektiven Gewahrwerdung signifikant veraendert, sondern dass die Amplitude der ERN auch fehlerbezogene Verhaltensadaptationsprozesse wie das post-error slowing (PES) vorhersagt, eine relative Reaktionszeitverlangsamung im Versuchsdurchgang nach Handlungsfehlern. Zur Generierung des letzteren Befundes wurde zudem im Rahmen dieser Dissertation eine stochastische Methode zur automatischen Identifikation von Signalkomponenten aus einem Skalp-EEG entwickelt, die auch ueber die Fehlerforschung hinaus zur Anwendung kommen kann. Zudem wurde die Rolle des autonomen Nervensystems bei der bewussten Gewahrwerdung von Handlungsfehlern untersucht, operationalisiert durch Herzrate und Pupillendilation nach Fehlern. Die Befunde dieser Analyse, zusammen mit den EKP-Befunden und Verhaltensdaten wurden dann in ein umfassendes Modell der Repraesentation von Handlungsfehlern bei der subjektiven Gewahrwerdung selbiger integriert

Efficient multipole representation for matter-wave optics

Technical optics with matter waves requires a universal description of three-dimensional traps, lenses, and complex matter-wave fields. In analogy to the two-dimensional Zernike expansion in beam optics, we present a three-dimensional multipole expansion for Bose-condensed matter waves and optical devices. We characterize real magnetic chip traps, optical dipole traps, and the complex matter-wave field in terms of spherical harmonics and radial Stringari polynomials. We illustrate this procedure for typical harmonic model potentials as well as real magnetic and optical dipole traps. Eventually, we use the multipole expansion to characterize the aberrations of a ballistically interacting expanding Bose-Einstein condensate in (3+1)-dimensions. In particular, we find deviations from the quadratic phase ansatz in the popular scaling approximation. This universal multipole description of aberrations can be used to optimize matter-wave optics setups, for example in matter-wave interferometers

Surface enlargement in the rumen of free-ranging muskoxen ( Ovibos moschatus )

The intraruminal papillation pattern indicates the degree of rumen contents stratification and is related to the feeding niche of a ruminant. Muskoxen (Ovibos moschatus) display a variety of morphophysiological adaptations typical for grazers. We investigated the intraruminal papillation of 22 free-ranging muskoxen from five different months by comparing the surface enlargement factor both between seasons and between individual rumen regions. The seasonal pattern of rumen papillation indicated a distinct seasonality in food quality. The intraruminal papillation indicated a moderate degree of rumen contents stratification typical for intermediate feeders. The nutritional ecology of muskoxen is characterised by specific morphophysiological adaptations to a grass-dominated diet that nevertheless allow extensive seasonal use of browse forag

Constrained-Differential-Kinematics-Decomposition-Based NMPC for Online Manipulator Control with Low Computational Costs

Flexibility combined with the ability to consider external constraints comprises the main advantages of nonlinear model predictive control (NMPC). Applied as a motion controller, NMPC enables applications in varying and disturbed environments, but requires time-consuming computations. Hence, given the full nonlinear multi-DOF robot model, a delay-free execution providing short control horizons at appropriate prediction horizons for accurate motions is not applicable in common use. This contribution introduces an approach that analyzes and decomposes the differential kinematics similar to the inverse kinematics method to assign Cartesian boundary conditions to specific systems of equations during the model building, reducing the online computational costs. The resulting fully constrained NMPC realizes the translational obstacle avoidance during trajectory tracking using a reduced model considering both joint and Cartesian constraints coupled with a Jacobian transposed controller performing the end-effector’s orientation correction. Apart from a safe distance from the obstacles, the presented approach does not lead to any limitations of the reachable workspace, and all degrees of freedom (DOFs) of the robot are used. The simulative evaluation in Gazebo using the Stäubli TX2-90 commanded of ROS on a standard computer emphasizes the significantly lower online computational costs, accuracy analysis, and extended adaptability in obstacle avoidance, providing additional flexibility. An interpretation of the new concept is discussed for further use and extensions

Supersymmetric Signals in e−e−e^-e^- Collisions

We consider the production and decay of selectrons and charginos in $e^-e^-$ collisions. The advantage over usual $e^+e^-$ collisions is the very low level of standard model backgrounds which should make the discovery of selectrons or charginos relatively straightforward. The use of polarized beams provides an additional powerful tool to determine the supersymmetry parameters.Comment: 18 pages including 8 figures, included as uufiled .ps files. LaTeX with axodraw.sty for Feynman graphs, epsf.sty for figures; the texfile and complete PSfile are available via ftp from pss058.psi.ch. CERN-TH.6807/93, MPI-Ph/93-28, PSI-93-1

Human-Centric Process-Aware Information Systems (HC-PAIS)

Process-Aware Information Systems (PAIS) support organizations in managing and automating their processes. A full automation of processes is in particular industries, such as service-oriented markets, not practicable. The integration of humans in PAIS is necessary to manage and perform processes that require human capabilities, judgments and decisions. A challenge of interdisciplinary PAIS research is to provide concepts and solutions that support human integration in PAIS and human orientation of PAIS in a way that provably increase the PAIS users' satisfaction and motivation with working with the Human-Centric Process Aware Information System (HC-PAIS) and consequently influence users' performance of tasks. This work is an initial step of research that aims at providing a definition of Human-Centric Process Aware Information Systems (HC-PAIS) and future research challenges of HC-PAIS. Results of focus group research are presented.Comment: 8 page

Wavelength-converted light sources in fluorescence-based methods in medical technology

This contribution proposes phosphors as excitation for fluorescence analysis and evaluates their potential in this application area. Aim of this research is to provide a method which allows to quantify how well a phosphor fits as excitation in a given optical system with spectral filters for fluorescence analysis. The approach consists of a mathematical calculation of crosstalk which is first applied to abstract and subsequentially defined phosphor emission spectra. The resulting crosstalk is used as measure indicating the fit of a phosphor spectrum. Result of this contribution is a detailed description of the applied method as well as an example exercise on a given optical system which gives an impression of possibilities phosphors offer in this application. The presented method is applicable to any (new) phosphor or even LED spectra. Especially evaluations on the example optical system allow conclusions which help to design future optical systems