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- ItemWPM package manager version 1.0 : software documentation(Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2010) Streckenbach, TimoWPM is a command-line tool designed to support build and installation facilities. It is implemented as a collection of script files, written in Bourne shell syntax. For the sake of portability the code takes care of the common pitfalls of shell programming.
- ItemTetGen : a 3D Delaunay tetrahedral mesh generator version 1.2 user's manual(Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2002) Si, HangThis technical report describes the main features and the using of TetGen, a 3D Delaunay tetrahedral mesh generator. Based on the most recent developments in mesh generation algorithms, this program has been specifically designed to fulfill the task of automatically generating high quality tetrahedral meshes, which are suitable for scientific computing using numerical methods such as finite element and finite volume methods. In this document, the user will learn how to create 3D tetrahedral meshes using TetGen's input files and command line switches. Various examples were given for better understanding. This document describes the features of the version 1.2.
- ItemModel-based cluster analysis applied to flow cytometry data of phytoplankton(Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2002) Mucha, H.-J.; Simon, U.; Brüggemann, R.Starting from well-known model-based clustering models equivalent formulations for some special models based on pairwise distances are presented. Moreover, these models can be generalized in order to taking into account both weights of observations and weights of variables. Well-known cluster analysis techniques like the iterative partitional K-means method or the agglomerative hierarchical Ward method are useful for discovering partitions or hierarchies in the underlying data. Here these methods are generalised in two ways, firstly by using weighted observations and secondly by allowing different volumes of clusters. Then a more general K-means approach based on pair-wise distances is recommended. Simulation studies are carried out in order to compare the new clustering techniques with the well-known ones. Afterwards a successful application in the field of freshwater ecology is presented. As an example, the cluster analysis of a snapshot from monitoring of phytoplankton (algae) is considered in more detail. Indeed, monitoring by microscope is very time- and work-consuming. Flow cytometry provides the opportunity to investigate algae communities in a semiautomatic way. Statistical data analysis and cluster analysis can at least support the investigations. Here a combination of agglomerative hierarchical clustering and iterative clustering is recommended. In order to give some insight into the data under investigation several univariate, bivariate and multivariate visualizations are proposed.
- ItemBenutzer-Handbuch DIPOG-1.4(Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2004) Schmidt, GuntherThis is the manual of the software package DIPOG, version 1.4, which can be used to simulate and optimize binary and multilevel optical gratings. The algorithms are based on the finite--element solution of a system of Helmholtz equations, which are equivalent to the timeharmonic electromagnetic field equations, and on gradient methods for solving optimization problems. The package offers several options to postprocess the calculated electromagnetic fields.
- ItemSimulation der Strahlhärtung von Stahl mit WIAS-SHarP(Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2002) Buchwalder, A.; Hömberg, D.; Jurke, Th.; Spies, H.-J.; Weiss, W.Die Software WIAS-SHarP zur Simulation der Oberflaechenhaertung von Stahl mit Laser- und Elektronenstrahl wurde im Rahmen eines zweijaehrigen interdisziplinaeren Forschungsprojektes entwickelt. Das zugrunde liegende mathematische Modell besteht aus einem System gewoehnlicher Differentialgleichungen zur Beschreibung der Gefuegeumwandlungen, gekoppelt mit einer nichtlinearen Waermeleitungsgleichung sowie Komponenten zur Beschreibung der Energieeinkopplung. Um eine moeglichst breite Anwendbarkeit der Software zu gewaehrleisten, wurden werkstoffspezifische Kennwerte zum Umwandlungsverhalten fuer eine grosse Anzahl praxisrelevanter Staehle bereitgestellt. Zur Modellverifikation wurden experimentelle Untersuchungen bei beteiligten Industriepartnern durchgefuehrt und mit den entsprechenden Simulationsrechnungen verglichen.
- ItemDIPOG-2.0 : user guide direct problems for optical gratings over triangular grids(Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2003) Rathsfeld, A.[no abstract available]
- ItemBroadening of mode-locking pulses in quantum-dot semiconductor lasers : simulation, analysis and experiments(Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2010) Radziunas, Mindaugas; Vladimirov, Andrei G.; Viktorov, Evgeny A.; Fiol, Gerrit; Schmeckebier, Holger; Bimberg, DieterWe consider a mode-locked quantum-dot edge-emitting semiconductor laser consisting of a reverse biased saturable absorber and a forward biased amplifying section. To describe the dynamics of this laser we use the traveling wave model taking into account carrier exchange processes between a reservoir and the quantum dots. A comprehensive parameter study is presented and an analysis of mode-locking pulse broadening with an increase of injection current is performed. The results of our theoretical analysis are supported by experimental data demonstrating a strong pulse asymmetry in a monolithic two section quantum dot mode-locked laser
- ItemExperimental investigations on the suppression of Q-switching in monolithic 40 GHz mode-locked semiconductor lasers(Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2006) Hüttl, BerndInherent Q-switching as a source of intra-cavity pulse energy modulations, i.e. unwanted amplitude noise, is still a challenging task in order to fabricate monolithic mode-locked semiconductor lasers in view of different commercial applications. In this paper, the results of experimental investigations on the influence of the quantum well number on the occurrence and suppression of Q-switching in 40 GHz mode-locked multiple quantum well buried heterostructure lasers are presented. Improved mode-locked lasers emit short optical pulses (<=1.6 ps) with very low amplitude noise (1-2%) and timing jitter (50-100 fs).
- ItemStabilizing poor mass conservation in incompressible flow problems with large irrotational forcing and application to thermal convection(Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2011) Galvin, Keith J.; Linke, Alexander; Rebholz, Leo G.; Wilson, Nicholas E.We consider the problem of poor mass conservation in mixed finite element algorithms for flow problems with large rotation-free forcing in the momentum equation. We provide analysis that suggests for such problems, obtaining accurate solutions necessitates either the use of pointwise divergence-free finite elements (such as Scott-Vogelius), or heavy grad-div stabilization of weakly divergence-free elements. The theory is demonstrated in numerical experiments for a benchmark natural convection problem, where large irrotational forcing occurs with high Rayleigh numbers.
- ItemMaximal parabolic regularity for divergence operators on distribution spaces(Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2009) Haller-Dintelmann, Robert; Rehberg, JoachimWe show that elliptic second order operators A of divergence type fulfill maximal parabolic regularity on distribution spaces, even if the underlying domain is highly non-smooth, the coefficients of A are discontinuous and A is complemented with mixed boundary conditions. Applications to quasilinear parabolic equations with non-smooth data are presented