TY - GEN A1 - Ilgenfritz, Ernst-Michael A1 - Kerler, Werner A1 - Müller-Preussker, Michael A1 - Stüben, Hinnerk T1 - Parallel tempering in full QCD with Wilson fermions N2 - We study the performance of QCD simulations with dynamical Wilson fermions by combining the Hybrid Monte Carlo algorithm with parallel tempering on $10^4$ and $12^4$ lattices. In order to compare tempered with standard simulations, covariance matrices between sub-ensembles have to be formulated and evaluated using the general properties of autocorrelations of the parallel tempering algorithm. We find that rendering the hopping parameter $\kappa$ dynamical does not lead to an essential improvement. We point out possible reasons for this observation and discuss more suitable ways of applying parallel tempering to QCD. T3 - ZIB-Report - 01-33 KW - QCD KW - parallel tempering KW - correlation analysis Y1 - 2001 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-6593 ER - TY - GEN A1 - Sokolov, Vladimir V. A1 - Wolf, Thomas T1 - Classification of integrable polynomial vector evolution equations N2 - Several classes of systems of evolution equations with one or two vector unknowns are considered. We investigate also systems with one vector and one scalar unknown. For these classes all equations having the simplest higher symmetry are listed. T3 - ZIB-Report - 01-34 Y1 - 2001 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-6601 ER - TY - GEN A1 - Hohage, Thorsten A1 - Schmidt, Frank T1 - On the Numerical Solution of Nonlinear Schrödinger type equations in fiber optics N2 - The aim of this paper is to develop fast methods for the solution of nonlinear Schrödinger type equations in fiber optics. Using the method of lines we have to solve a stiff system of ordinary differential equations where the eigenvalues of the Jacobian are close to the imaginary axis. This is usually done by a Split Step method. Here we consider the extrapolation of Split Step methods with adaptive order and step size control. For more complicated nonlinearities, in particular stimulated Raman scattering, Split Step methods are less efficient since symmetry is either destroyed or requires much additional effort. In this case we use implicit Runge Kutta formulas of Gauß type. The key point for the efficient implementation of these methods is that the system of nonlinear algebraic equations can be solved without setting up the Jacobian. The proposed methods are compared to other methods, in particular exponential integrators, the method of Marcuse, and the method of Blow and Wood. T3 - ZIB-Report - 02-04 KW - nonlinear Schroedinger equation KW - split step methods KW - extrapolation KW - collocation methods Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-6715 ER - TY - GEN A1 - Krumke, Sven A1 - Rambau, Jörg T1 - Probieren geht über Studieren? Entscheidungshilfen für kombinatorische Online-Optimierungsprobleme in der innerbetrieblichen Logistik N2 - Die Automatisierung von innerbetrieblicher Logistik erfordert -- über die physikalische Steuerung von Geräten hinaus -- auch eine effiziente Organisation der Transporte: ein Aufgabenfeld der kombinatorischen Optimierung. Dieser Artikel illustriert anhand von konkreten Aufgabenstellungen die Online-Problematik (unvollständiges Wissen) sowie die Echtzeit-Problematik (beschränkte Rechenzeit), auf die man in der innerbetrieblichen Logistik trifft. Der Text gibt einen Überblick über allgemeine Konstruktionsprinzipien für Online-Algorithmen und Bewertungsmethoden, die bei der Entscheidung helfen, welche Algorithmen für eine vorliegende Problemstellung geeignet sind. T3 - ZIB-Report - 02-05 KW - Logistik KW - Hochregallagerbediengeräte KW - Kommissioniermobile KW - Aufzüge KW - Online-Optimierung KW - Echtzeit-Optimierung KW - Simulation KW - kompetitive Analyse Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-6723 ER - TY - GEN A1 - Reinefeld, Alexander A1 - Stüben, Hinnerk A1 - Schintke, Florian A1 - Din, George T1 - GuiGen: A Toolset for Creating Customized Interfaces for Grid User Communities N2 - \textsf{\itshape{GuiGen}} is a comprehensive set of tools for creating customized graphical user interfaces (GUIs). It draws from the concept of computing portals, which are here seen as interfaces to application-specific computing services for user communities. While \textsf{\itshape{GuiGen}} was originally designed for the use in computational grids, it can be used in client/server environments as well. Compared to other GUI generators, \textsf{\itshape{GuiGen}} is more versatile and more portable. It can be employed in many different application domains and on different target platforms. With \textsf{\itshape{GuiGen}}, application experts (rather than computer scientists) are able to create their own individually tailored GUIs. T3 - ZIB-Report - 02-06 KW - Grid computing KW - customized user interfaces KW - grid user communities KW - web portals KW - XML Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-6737 ER - TY - GEN A1 - Wagler, Annegret T1 - Antiwebs are Rank-Perfect N2 - \We discuss a nested collection of three superclasses of perfect graphs: near-perfect, rank-perfect, and weakly rank-perfect graphs. For that, we start with the description of the stable set polytope for perfect graphs and allow stepwise more general facets for the stable set polytopes of the graphs in each superclass. Membership in those three classes indicates how far a graph is away from being perfect. We investigate for webs and antiwebs to which of the three classes they belong. We provide a complete description of the facets of the stable set polytope for antiwebs (with help of a result due to Shepherd on near-bipartite graphs). The main result is that antiwebs are rankperfect. T3 - ZIB-Report - 02-07 KW - relaxations of perfect graphs KW - antiwebs KW - stable set polytope Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-6742 ER - TY - GEN A1 - Wolf, Thomas T1 - The integration of systems of linear PDEs using conservation laws of syzygies N2 - The purpose of the paper is to formulate and use syzygies for systems of linear PDEs. The computation of an equivalent of a GCD for linear partial differential operators will save us their factorization which is otherwise only possible algorithmically in special cases. After showing the computation with the new and the traditional method and comparing both in the next three sections, the algorithm is explained in general and an overview is given. T3 - ZIB-Report - 02-08 KW - PDE KW - syzygies KW - conservation laws Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-6751 ER - TY - GEN A1 - Eisenblätter, Andreas A1 - Grötschel, Martin A1 - Koster, Arie M.C.A. T1 - Frequenzplanung im Mobilfunk N2 - Telekommunikation ist seit Jahren \glqq in\grqq. Zunächst gab es einen enormen Aufschwung; neue Technologien und Dienste haben eine überwältigende, nicht vorhersehbare Akzeptanz gefunden. Derzeit ist -- ausgelöst durch die UMTS-Lizenzversteigerungen, Rezessions- und Sättigungstendenzen -- eine Krise zu verzeichnen. Viele (auch wir) sind davon überzeugt, dass technischer Fortschritt und nützliche Dienste demnächst die Stimmung wieder ändern werden. Wenigen ist allerdings bewusst, welche Rolle Mathematik bei der Entwicklung und dem effizienten Einsatz vieler der neuen Kommunikationstechnologien spielt. In diesem Artikel soll kein Überblick über diesen umfangreichen Themenkreis gegeben werden. Wir zeigen lediglich an einem konkreten Beispiel aus dem Mobilfunk, der Frequenzplanung in GSM-Funknetzen, was man durch geeignete Modellierung der praktischen Fragestellung und den Einsatz problemadäquater Algorithmen erreichen kann. T3 - ZIB-Report - 02-09 KW - Telekommunikation KW - Frequenzplanung KW - Mobilfunk KW - GSM-Funknetze Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-6762 ER - TY - GEN A1 - Borndörfer, Ralf A1 - Löbel, Andreas A1 - Weider, Steffen T1 - Integrierte Umlauf- und Dienstplanung im Öffentlichen Nahverkehr N2 - Wir beschreiben einen Ansatz zur integrierten Umlauf- und Dienstplanung im öffentlichen Nahverkehr. Der Ansatz zielt auf die Verbesserung des Gesamtwirkungsgrades dieser beiden Planungsschritte und auf die besondere Planungsproblematik im Regionalverkehr. Wir entwickeln dazu mathematische Optimierungstechniken für den Einsatz in den Planungssystemen MICROBUS II und DIVA. T3 - ZIB-Report - 02-10 KW - Integrierte Umlauf- und Dienstplanung KW - Umlaufplanung KW - Dienstplanung KW - Optimierung KW - Regionalverkehr Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-6773 ER - TY - GEN A1 - Hougardy, Stefan A1 - Wagler, Annegret T1 - Perfectness is an Elusive Graph Property N2 - A graph property is called elusive (or evasive) if every algorithm for testing this property has to read in the worst case $n\choose 2$ entries of the adjacency matrix of the given graph. Several graph properties have been shown to be elusive, e.g. planarity (Best et al) or $k$-colorability (Bollobas). A famous conjecture of Karp says that every non-trivial monotone graph property is elusive. We prove that a non-monotone but hereditary graph property is elusive: perfectness. T3 - ZIB-Report - 02-11 KW - perfect graph KW - elusive graph property Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-6787 ER - TY - GEN A1 - Weber, Marcus A1 - Galliat, Tobias T1 - Characterization of Transition States in Conformational Dynamics using Fuzzy Sets N2 - Recently, a novel approach for the analysis of molecular dynamics on the basis of a transfer operator has been introduced. Therein conformations are considered to be disjoint metastable clusters within position space of a molecule. These clusters are defined by almost invariant characteristic functions that can be computed via {\em Perron Cluster} analysis. The present paper suggests to replace crisp clusters with {\em fuzzy} clusters, i.e. to replace characteristic functions with membership functions. This allows a more sufficient characterization of transiton states between different confor conformations and therefore leads to a better understanding of molecular dynamics. Fur thermore, an indicator for the uniqueness of metastable fuzzy clusters and a fast algorithm for the computation of these clusters are described. Numerical examples are included. T3 - ZIB-Report - 02-12 KW - biochemical conformations KW - conformational dynamics KW - molecular dynamics KW - cluster analysis KW - transition states KW - fuzzy sets Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-6791 ER - TY - GEN T1 - Jahresbericht 1993 T3 - Jahresbericht - 1993 KW - Annual Report Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-9668 SN - 0934-5892 ER - TY - GEN T1 - Jahresbericht 1992 T3 - Jahresbericht - 1992 KW - Annual Report Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-9686 SN - 0934-5892 ER - TY - GEN T1 - Jahresbericht 1994 T3 - Jahresbericht - 1994 KW - Annual Report Y1 - 1995 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-9699 SN - 0934-5892 ER - TY - GEN T1 - Jahresbericht 1995 T3 - Jahresbericht - 1995 KW - Annual Report Y1 - 1996 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-9704 SN - 0934-5892 ER - TY - GEN T1 - Jahresbericht 2006 T3 - Jahresbericht - 2006 KW - Annual Report Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-9812 SN - 0934-5892 ER - TY - GEN T1 - Jahresbericht 1991 T3 - Jahresbericht - 1991 KW - Annual Report Y1 - 1992 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-9825 SN - 0934-5892 ER - TY - GEN T1 - Jahresbericht 1990 T3 - Jahresbericht - 1990 KW - Annual Report Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-9831 SN - 0934-5892 ER - TY - GEN T1 - Jahresbericht 1989 T3 - Jahresbericht - 1989 KW - Annual Report Y1 - 1990 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-9847 SN - 0934-5892 ER - TY - GEN T1 - Jahresbericht 1988 T3 - Jahresbericht - 1988 KW - Annual Report Y1 - 1989 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-9858 SN - 0934-5892 ER - TY - GEN T1 - Jahresbericht 1987 T3 - Jahresbericht - 1987 KW - Annual Report Y1 - 1988 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-9860 SN - 0933-7903 ER - TY - GEN T1 - Tätigkeitsbericht 1986 T3 - Jahresbericht - 1986 KW - Annual Report KW - Jahresbericht Y1 - 1987 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-9871 ER -