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  • 1995-1999  (131,356)
  • 1985-1989  (15)
  • 1996  (131,356)
Source
Material
Years
Year
Person/Organisation
Keywords
Language
  • 1
    Electronic Resource
    Electronic Resource
    A measurement of τ polarization in Z^0 decays (1992-8977)
    Amsterdam : Elsevier
    Physics Letters B 294 (1992), S. 466-478 
    Details
    ISSN: 0370-2693
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0370-2693(92)91549-O
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Measurement of the average lifetime of b hadrons (1993-4325)
    Amsterdam : Elsevier
    Physics Letters B 317 (1993), S. 474-484 
    Details
    ISSN: 0370-2693
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0370-2693(93)91027-K
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    Paper (German National Licenses)
    Fulltext
  • 3
    Book
    Book
    Computing : archives for informatics and numerical computation; Supplementum (1977-2003)
    Wien [u.a.] :Springer, ; 1.1977 - 16.2003; damit Ersch. eingest.
    Details
    Title: Computing : archives for informatics and numerical computation; Supplementum
    Publisher: Wien [u.a.] :Springer,
    Year of publication: 1977-2003
    Dates of Publication: 1.1977 - 16.2003; damit Ersch. eingest.
    Type of Medium: Book
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    ZIB Catalog
    Zuse Institute Berlin get availability status
  • 4
    Online Resource
    Online Resource
    Journal of molecular modeling (1996-2002)
    Berlin ; Heidelberg :Springer, ; 1.1995(1996) - 8.2002
    Details
    Title: Journal of molecular modeling
    Publisher: Berlin ; Heidelberg :Springer,
    Year of publication: 1996-2002
    Dates of Publication: 1.1995(1996) - 8.2002
    ISSN: 0949-183X
    Type of Medium: Online Resource
    Language: Undetermined
    Subsequent Title: Forts. ---〉:Journal of molecular modeling
    Note: Kumuliert jeweils den abgeschlossenen Jg. der Internetausg.
    Parallel Title: Druckausg. ---〉:Molecular modeling annual
    URL: http://www.springerlink.com/content/100529
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    ZIB Catalog
    Zuse Institute Berlin
  • 5
    Journal/Serial
    Journal/Serial
    SIGBIO newsletter / (from 1969-2001)
    New York, NY :ACM, ; 1.1969 - 7.1975/76; N.S. 1.1976 - 21.2001,1; damit Ersch. eingest.
    Details
    Title: SIGBIO newsletter /
    Author: Association for Computing Machinery / Special Interest Group on Biomedical Computing
    Publisher: New York, NY :ACM,
    Year of publication: 1969-2001
    Dates of Publication: 1.1969 - 7.1975/76; N.S. 1.1976 - 21.2001,1; damit Ersch. eingest.
    ISSN: 0163-5697
    Type of Medium: Journal/Serial
    Language: Undetermined
    Parallel Title: Internetausg. ---〉:Biomedical computing
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    ZIB Catalog
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  • 6
    Journal/Serial
    Journal/Serial
    ¬The¬ journal of logic programming (from 1984-2000)
    New York, NY :North-Holland, ; 1.1984 - 46.2000
    Details
    Title: ¬The¬ journal of logic programming
    Publisher: New York, NY :North-Holland,
    Year of publication: 1984-2000
    Dates of Publication: 1.1984 - 46.2000
    ISSN: 0743-1066
    Type of Medium: Journal/Serial
    Language: Undetermined
    Subsequent Title: Forts. ---〉:¬The¬ journal of logic and algebraic programming
    Parallel Title: Internetausg. ---〉:¬The¬ journal of logic and algebraic programming
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  • 7
    Journal/Serial
    Journal/Serial
    CWI quarterly (from 1988-1999)
    Amsterdam :CWI, ; 1.1988 - 12.1999; damit Ersch. eingest.
    Details
    Title: CWI quarterly
    Author: Centrum voor Wiskunde en Informatica 〈Amsterdam〉
    Publisher: Amsterdam :CWI,
    Year of publication: 1988-1999
    Dates of Publication: 1.1988 - 12.1999; damit Ersch. eingest.
    ISSN: 0168-826X , 0922-5366
    Type of Medium: Journal/Serial
    Language: Undetermined
    Former Title: Vorg. ---〉:Centrum voor Wiskunde en Informatica 〈Amsterdam〉: CWI newsletter
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    ZIB Catalog
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  • 8
    E-Resource
    E-Resource
    Medical image analysis CD : an international journal of computer vision, visualization and image- guided intervention in medicine (1996-1999)
    Oxford :Univ. Press, ; 1.1996/97 - 3.1999; damit Ersch. eingest.
    Details
    Title: Medical image analysis CD : an international journal of computer vision, visualization and image- guided intervention in medicine
    Publisher: Oxford :Univ. Press,
    Year of publication: 1996-1999
    Dates of Publication: 1.1996/97 - 3.1999; damit Ersch. eingest.
    ISSN: 1361-8431
    Type of Medium: Electronic Resource
    Language: Undetermined
    Parallel Title: Druckausg. ---〉:Medical image analysis
    Parallel Title: Internetausg. ---〉:Medical image analysis
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    ZIB Catalog
    Zuse Institute Berlin get availability status
  • 9
    Book
    Book
    Computer personnel : a quarterly publ. of the Special Interest Group on Computer Personnel Research, SIGCPR (1971-1999)
    New York, NY :ACM, ; Nachgewiesen 2.1971 - 20.1999,4; damit Ersch. eingest.
    Details
    Title: Computer personnel : a quarterly publ. of the Special Interest Group on Computer Personnel Research, SIGCPR
    Publisher: New York, NY :ACM,
    Year of publication: 1971-1999
    Dates of Publication: Nachgewiesen 2.1971 - 20.1999,4; damit Ersch. eingest.
    ISSN: 0160-2497
    Type of Medium: Book
    Parallel Title: Internetausg. ---〉:Computer personnel
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  • 10
    Journal/Serial
    Journal/Serial
    SIGNUM newsletter (from 1969-1998)
    New York, NY :ACM, ; 4.1969 - 33.1998,2; damit Ersch. eingest
    Details
    Title: SIGNUM newsletter
    Author: Association for Computing Machinery / Special Interest Group on Numerical Mathematics
    Publisher: New York, NY :ACM,
    Year of publication: 1969-1998
    Dates of Publication: 4.1969 - 33.1998,2; damit Ersch. eingest
    ISSN: 0163-5778
    Type of Medium: Journal/Serial
    Former Title: Vorg. ---〉:Association for Computing Machinery / Special Interest Committee on Numerical Mathematics: SICNUM newsletter
    Additional Information: 16,3=3,2 von:Association for Computing Machinery / Technical Committee on Fortran: FORTEC forum
    Parallel Title: Internetausg. ---〉:Numerical mathematics
    URL: Nur Table of Contents.
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  • 11
    Journal/Serial
    Journal/Serial
    Computers in physics / (from 1987-1998)
    Woodbury, NY :AIP, ; 1.1987,1(Nov./Dez.); 2.1988 - 12.1998
    Details
    Title: Computers in physics /
    Contributer: American Institute of Physics
    Publisher: Woodbury, NY :AIP,
    Year of publication: 1987-1998
    Dates of Publication: 1.1987,1(Nov./Dez.); 2.1988 - 12.1998
    ISSN: 0894-1866
    Type of Medium: Journal/Serial
    Language: Undetermined
    Subsequent Title: Forts. ---〉:Computing in science & engineering
    URL: http://www.aip.org/cip/
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  • 12
    Journal/Serial
    Journal/Serial
    SIGART bulletin : a quarterly publ. of the Special Interest Group on Artificial Intelligence (from 1990-1998)
    New York, NY :ACM, ; 1.1990 - 9.1998
    Details
    Title: SIGART bulletin : a quarterly publ. of the Special Interest Group on Artificial Intelligence
    Author: Association for Computing Machinery / Special Interest Group on Artificial Intelligence
    Publisher: New York, NY :ACM,
    Year of publication: 1990-1998
    Dates of Publication: 1.1990 - 9.1998
    ISSN: 1053-4830
    Type of Medium: Journal/Serial
    Language: Undetermined
    Former Title: Vorg. ---〉:Association for Computing Machinery / Special Interest Group on Artificial Intelligence: SIGART newsletter
    Subsequent Title: Forts. ---〉:Intelligence
    Parallel Title: Internetausg. ---〉:Artificial intelligence
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  • 13
    Journal/Serial
    Journal/Serial
    Unix review : the publication for the Unix community (from 1983-1998)
    San Francisco, Calif. :Miller Freeman, ; 1.1983 - 16.1998,3
    Details
    Title: Unix review : the publication for the Unix community
    Publisher: San Francisco, Calif. :Miller Freeman,
    Year of publication: 1983-1998
    Dates of Publication: 1.1983 - 16.1998,3
    ISSN: 0742-3136
    Type of Medium: Journal/Serial
    Language: Undetermined
    Subsequent Title: Forts. ---〉:Unix review's performance computing
    Parallel Title: Internetausg. ---〉:Unix review.com
    URL: Zugriff lizenzfrei
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  • 14
    Journal/Serial
    Journal/Serial
    Computer networks and ISDN systems : the international journal of computer and telecommunications networking (from 1985-1998)
    Amsterdam [u.a.] :Elsevier [u.a.], ; 9.1985 - 30.1998
    Details
    Title: Computer networks and ISDN systems : the international journal of computer and telecommunications networking
    Publisher: Amsterdam [u.a.] :Elsevier [u.a.],
    Year of publication: 1985-1998
    Dates of Publication: 9.1985 - 30.1998
    ISSN: 0169-7552 , 0376-5075
    Type of Medium: Journal/Serial
    Language: Undetermined
    Subsequent Title: Vorg. u. Forts. ---〉:Computer networks
    Note: Computer networks for research in Europe
    Additional Information: In 14,1=15 von:Networkshop: Conference report
    Additional Information: 16,1/2=4; 17,4/5=5 von:European Networkshop: European Networkshop
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  • 15
    Book
    Book
    Online : erfolgreiches Informationsmanagement, ADI-Nachrichten, ÖVD ; Organ d. ADI - Anwenderverband Deutscher Informationsverarbeiter e.V (1973-1997)
    Bergheim :DATACOM-Zeitschriften-Verl., | Köln Müller -1993,9 ; 11.1973 - 14.1976; 19.1981 - 20.1982; 1983 - 1994; 32.1995 - 34.1997,10
    Details
    Title: Online : erfolgreiches Informationsmanagement, ADI-Nachrichten, ÖVD ; Organ d. ADI - Anwenderverband Deutscher Informationsverarbeiter e.V
    Contributer: Anwenderverband Deutscher Informationsverarbeiter
    Publisher: Bergheim :DATACOM-Zeitschriften-Verl., , Köln Müller -1993,9
    Year of publication: 1973-1997
    Dates of Publication: 11.1973 - 14.1976; 19.1981 - 20.1982; 1983 - 1994; 32.1995 - 34.1997,10
    ISSN: 0340-1545 , 0179-6623 , 0342-9393
    Type of Medium: Book
    Language: Undetermined
    Former Title: Vorg. ---〉:Zeitschrift für Datenverarbeitung
    Subsequent Title: 15.1977 - 18.1980 ---〉:ADL-Verband für Informationsverarbeitung: ADL-Nachrichten, Online
    Subsequent Title: Aufgeg. in ---〉:Information week
    Note: Später ohne Zählung
    Additional Information: Beil. ---〉:Drucker spezial
    Additional Information: Beil. ---〉:Online / special
    Additional Information: Darin ---〉:Anwenderverband Deutscher Informationsverarbeiter: ADI-Nachrichten, ÖVD
    Additional Information: Beil. ---〉:Pro info
    Additional Information: Beil. ---〉:Online-Info
    Additional Information: 1996 darin ---〉:Datacom-Special
    Parallel Title: 19.1981 auch in ---〉:Öffentliche Verwaltung und Datenverarbeitung
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  • 16
    Journal/Serial
    Journal/Serial
    LISP and symbolic computation : an internat. journal ; a forum for current and envolving symbolic computing, focusing on LISP and object-oriented programming (from 1988-1997)
    Dordrecht [u.a.] :Kluwer Acad. Publ., ; 1.1988 - 10.1997
    Details
    Title: LISP and symbolic computation : an internat. journal ; a forum for current and envolving symbolic computing, focusing on LISP and object-oriented programming
    Publisher: Dordrecht [u.a.] :Kluwer Acad. Publ.,
    Year of publication: 1988-1997
    Dates of Publication: 1.1988 - 10.1997
    ISSN: 0892-4635
    Type of Medium: Journal/Serial
    Language: Undetermined
    Subsequent Title: Forts. ---〉:Higher order and symbolic computation
    Parallel Title: Internetausg. ---〉:Higher-order and symbolic computation
    URL: Zugriff nur bis zu den Abstracts möglich.
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  • 17
    Journal/Serial
    Journal/Serial
    World Wide Web journal : W3J; a publication of the World Wide Web Consortium (from 1995-1997)
    Sebastopol, CA, ; 1.1995/96 - 2.1997,4; damit Ersch. eingest.
    Details
    Title: World Wide Web journal : W3J; a publication of the World Wide Web Consortium
    Publisher: Sebastopol, CA,
    Year of publication: 1995-1997
    Dates of Publication: 1.1995/96 - 2.1997,4; damit Ersch. eingest.
    ISSN: 1085-2301
    Type of Medium: Journal/Serial
    Language: Undetermined
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  • 18
    Journal/Serial
    Journal/Serial
    Annals of numerical mathematics : journal edition (from 1994-1997)
    Basel :Baltzer, ; 1.1994 - 4.1997; damit Ersch. eingest
    Details
    Title: Annals of numerical mathematics : journal edition
    Publisher: Basel :Baltzer,
    Year of publication: 1994-1997
    Dates of Publication: 1.1994 - 4.1997; damit Ersch. eingest
    ISSN: 1021-2655
    Type of Medium: Journal/Serial
    Language: Undetermined
    Parallel Title: Internetausg. : Annals of numerical algorithms
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  • 19
    E-Resource
    E-Resource
    Software 〈Chichester〉 : practice & experience ; SP & E ; SP & E archive (1994-1997)
    Chichester [u.a.] :Wiley, ; 1/20.1971/90(1994) - 21/25.1991/95(1997); damit Ersch. eingest.
    Details
    Title: Software 〈Chichester〉 : practice & experience ; SP & E ; SP & E archive
    Publisher: Chichester [u.a.] :Wiley,
    Year of publication: 1994-1997
    Dates of Publication: 1/20.1971/90(1994) - 21/25.1991/95(1997); damit Ersch. eingest.
    ISSN: 0038-0644
    Type of Medium: Electronic Resource
    Language: Undetermined
    Additional Information: 1/20=3; 21/25=5 von:Software 〈Chichester〉 / Special
    Parallel Title: Druckausg. ---〉:Software 〈Chichester〉
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  • 20
    Journal/Serial
    Journal/Serial
    ¬The¬ international journal of supercomputer applications and high performance computing (from 1987-1997)
    Thousand Oaks, Calif. :Sage Science Press, ; 1.1987 - 11.1997
    Details
    Title: ¬The¬ international journal of supercomputer applications and high performance computing
    Publisher: Thousand Oaks, Calif. :Sage Science Press,
    Year of publication: 1987-1997
    Dates of Publication: 1.1987 - 11.1997
    ISSN: 1078-3482 , 0890-2720
    Type of Medium: Journal/Serial
    Subsequent Title: Forts. ---〉:¬The¬ international journal of high performance computing applications
    Parallel Title: Internetausg. ---〉:¬The¬ international journal of high performance computing applications
    URL: Zugriff auf diese Zeitschrift für die Jahrgänge 3. 1989 - 11. 1997 innerhalb der ZIB Domain (IP Adressen: 130.73.*.*) möglich.
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  • 21
    Journal/Serial
    Journal/Serial
    Supercomputer : bimonthly magazine on supercomputing in the Netherlands (from 1984-1997)
    Amsterdam :Amsterdam Universities Computing Centre, ; Nr. 1.1984 - 69.1997; damit Ersch. eingest.
    Details
    Title: Supercomputer : bimonthly magazine on supercomputing in the Netherlands
    Publisher: Amsterdam :Amsterdam Universities Computing Centre,
    Year of publication: 1984-1997
    Dates of Publication: Nr. 1.1984 - 69.1997; damit Ersch. eingest.
    ISSN: 0168-7875
    Type of Medium: Journal/Serial
    Language: Undetermined
    Note: Teils auch mit Jg.-Zählung
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  • 22
    Journal/Serial
    Journal/Serial
    SIGICE bulletin : a monthly publication of the ACM Special Interest Group on Individual Computing Environments (from 1994-1997)
    New York, NY :ACM, ; 19.1993/94,3(1994) - 23.1997/98,2(1997); damit Ersch. eingest.
    Details
    Title: SIGICE bulletin : a monthly publication of the ACM Special Interest Group on Individual Computing Environments
    Author: Association for Computing Machinery / Special Interest Group on Individual Computing Environments
    Publisher: New York, NY :ACM,
    Year of publication: 1994-1997
    Dates of Publication: 19.1993/94,3(1994) - 23.1997/98,2(1997); damit Ersch. eingest.
    Type of Medium: Journal/Serial
    Language: Undetermined
    Former Title: Vorg. ---〉:Association for Computing Machinery / Special Interest Group on Small and Personal Computing Systems and Applications: SIGSMALL - PC notes
    Parallel Title: Internetausg. ---〉:Association for Computing Machinery / Special Interest Group on Individual Computing Environments: ACM SIGICE bulletin
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  • 23
    facet.materialart.
    Unknown
    Optimierung des Fahrzeugumlaufs im Öffentlichen Nahverkehr (1996)
    Details
    Publication Date: 2014-02-26
    Description: This paper addresses the problem of scheduling vehicles in a public mass transportation system. We show how this problem can be modelled as a special multicommodity flow problem and outline the solution methodology we have developed. Based on polyhedral investigations, we have designed and implemented a branch&cut algorithm and various heuristics with which real vehicle scheduling problems of truely large scale can be solved to optimality. We describe some implementation issues and report computational results.
    Keywords: ddc:000
    Language: German
    Type: reportzib , doc-type:preprint
    Format: application/postscript
    Format: application/pdf
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    OPUS
  • 24
    facet.materialart.
    Unknown
    Sixty Years of Computation - The Machines of Konrad Zuse (1996)
    Details
    Publication Date: 2014-02-26
    Description: This paper provides the {\em first} detailed description of the architecture of the computing machines Z1 and Z3 designed by Konrad Zuse in Berlin between 1936 to 1941. The necessary information was obtained from a careful evaluation of the patent application filed by Zuse in 1941. Additional insight was gained from a software simulation of the machine's logic. The Z1 was built using purely mechanical components, the Z3 using electromechanical relays. However, both machines shared a common logical structure and the programming model was exactly the same. We argue that both the Z1 and the Z3 possessed features akin to those of modern computers: memory and processor were separate units, the processor could handle floating-point numbers and compute the four basic arithmetical operations as well as the square root of a number. The program was stored on punched tape and was read sequentially. In the last section of this paper we bring the architecture of the Z1 and Z3 into historical perspective by offering a comparison with computing machines built in other countries.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
    Format: application/postscript
    Format: application/pdf
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    OPUS
  • 25
    facet.materialart.
    Unknown
    Parallelizing the Dual Simplex Method (1996)
    Details
    Publication Date: 2014-11-11
    Description: We study the parallelization of the steepest-edge version of the dual simplex algorithm. Three different parallel implementations are examined, each of which is derived from the CPLEX dual simplex implementation. One alternative uses PVM, one general-purpose System V shared-memory constructs, and one the PowerC extension of C on a Silicon Graphics multi-processor. These versions were tested on different parallel platforms, including heterogeneous workstation clusters, Sun S20-502, Silicon Graphics multi-processors, and an IBM SP2. We report on our computational experience.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
    Format: application/postscript
    Format: application/pdf
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  • 26
    facet.materialart.
    Unknown
    Dual Decomposition in Stochastic Integer Programming (1996)
    Details
    Publication Date: 2014-02-26
    Description: We present an algorithm for solving stochastic integer programming problems with recourse, based on a dual decomposition scheme and Lagrangian relaxation. The approach can be applied to multi-stage problems with mixed-integer variables in each time stage. %We outline a branch-and-bound algorithm for obtaining primal feasible and %possibly optimal solutions. Numerical experience is presented for some two-stage test problems.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
    Format: application/postscript
    Format: application/pdf
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  • 27
    facet.materialart.
    Unknown
    Computation of Essential Molecular Dynamics by Subdivision Techniques I: Basic Concept (1996)
    Details
    Publication Date: 2014-02-26
    Description: The paper presents the concept of a new type of algorithm for the numerical computation of what the authors call the {\em essential dynamics\/} of molecular systems. Mathematically speaking, such systems are described by Hamiltonian differential equations. In the bulk of applications, individual trajectories are of no specific interest. Rather, time averages of physical observables or relaxation times of conformational changes need to be actually computed. In the language of dynamical systems, such information is contained in the natural invariant measure (infinite relaxation time) or in almost invariant sets ("large" finite relaxation times). The paper suggests the direct computation of these objects via eigenmodes of the associated Frobenius-Perron operator by means of a multilevel subdivision algorithm. The advocated approach is different to both Monte-Carlo techniques on the one hand and long term trajectory simulation on the other hand: in our setup long term trajectories are replaced by short term sub-trajectories, Monte-Carlo techniques are just structurally connected via the underlying Frobenius-Perron theory. Numerical experiments with a first version of our suggested algorithm are included to illustrate certain distinguishing properties. A more advanced version of the algorithm will be presented in a second part of this paper.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
    Format: application/postscript
    Format: application/pdf
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  • 28
    facet.materialart.
    Unknown
    Chebyshev-Approximation for Wavepacket-Dynamics: better than expected (1996)
    Details
    Publication Date: 2014-02-26
    Description: The aim of this work is to study the accuracy and stability of the Chebyshev--approximation method as a time--discretization for wavepacket dynamics. For this frequently used discretization we introduce estimates of the approximation and round--off error. These estimates mathematically confirm the stability of the Chebyshev--approximation with respect to round--off errors, especially for very large stepsizes. But the results also disclose threads to the stability due to large spatial dimensions. All theoretical statements are illustrated by numerical simulations of an analytically solvable example, the harmonic quantum oszillator.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
    Format: application/postscript
    Format: application/pdf
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  • 29
    facet.materialart.
    Unknown
    Twodimensional Cascadic Finite Element Computations of Combustion Problems (1996)
    Details
    Publication Date: 2014-02-26
    Description: We present an integrated time--space adaptive finite element method for solving systems of twodimensional nonlinear parabolic systems in complex geometry. The partial differential system is first discretized in time using a singly linearly implicit Runge--Kutta method of order three. Local time errors for the step size control are defined by an embedding strategy. These errors are used to propose a new time step by a PI controller algorithm. A multilevel finite element method with piecewise linear functions on unstructured triangular meshes is subsequently applied for the discretization in space. The local error estimate of the finite element solution steering the adaptive mesh refinement is obtained solving local problems with quadratic trial functions located essentially at the edges of the triangulation. This two--fold adaptivity successfully ensures an a priori prescribed tolerance of the solution. The devised method is applied to laminar gaseous combustion and to solid--solid alloying reactions. We demonstrate that for such demanding applications the employed error estimation and adaption strategies generate an efficient and versatile algorithm.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
    Format: application/postscript
    Format: application/pdf
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  • 30
    facet.materialart.
    Unknown
    Weinstein's Functions and the Askey-Gasper Identity (1996)
    Details
    Publication Date: 2015-06-01
    Description: \iffalse Recently, Todorov and Wilf independently realized that de Branges' original proof of the Bieberbach and Milin conjectures and the proof that was later given by Weinstein deal with the same special function system that de Branges had introduced in his work. In this article, we present an elementary proof of this statement based on the defining differential equations system rather than the closed representation of de Branges' function system. Our proof does neither use special functions (like Wilf's) nor the residue theorem (like Todorov's) nor the closed representation (like both), but is purely algebraic. On the other hand, by a similar algebraic treatment, the closed representation of de Branges' function system is derived. Our whole contribution can be looked at as the study of properties of the Koebe function. Therefore, in a very elementary manner it is shown that the known proofs of the Bieberbach and Milin conjectures can be understood as a consequence of the Löwner differential equation, plus properties of the Koebe function. \fi In his 1984 proof of the Bieberbach and Milin conjectures de Branges used a positivity result of special functions which follows from an identity about Jacobi polynomial sums that was found by Askey and Gasper in 1973, published in 1976. In 1991 Weinstein presented another proof of the Bieberbach and Milin conjectures, also using a special function system which (by Todorov and Wilf) was realized to be the same as de Branges'. In this article, we show how a variant of the Askey-Gasper identity can be deduced by a straightforward examination of Weinstein's functions which intimately are related with a Löwner chain of the Koebe function, and therefore with univalent functions.
    Keywords: ddc:000
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    Solving Large-Scale Real-World Minimum-Cost Flow Problems by a Network Simplex Method (1996)
    Details
    Publication Date: 2014-11-02
    Description: This paper presents a large-scale real-world application of the minimum-cost flow problem, describes some details of a new implementation of the network simplex algorithm, and reports on computational comparisions. The real-world test sets include minimum-cost flow problems that are based on single-depot vehicle scheduling problems and on a Lagrangean relaxation of multiple-depot vehicle scheduling problems. Some of the problems are extremely large with up to 42,000 nodes and 20,000,000 arcs. The standard test problems are generated with NETGEN and include parts of the DIMACS standard problems. Our network simplex code is compared with \mbox{RELAX-IV}, Cost Scaling 2 version 3.4, and CPLEX's network solver NETOPT.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
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    On the Glivenko-Cantelli Problem in Stochastic Programming: Linear Recourse and Extensions (1996)
    Details
    Publication Date: 2014-02-26
    Description: Integrals of optimal values of random optimization problems depending on a finite dimensional parameter are approximated by using empirical distributions instead of the original measure. Under fairly broad conditions, it is proved that uniform convergence of empirical approximations of the right hand sides of the constraints implies uniform convergence of the optimal values in the linear and convex case.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
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    Adaptive Rothe's Method for the 2D Wave Equation (1996)
    Details
    Publication Date: 2014-02-26
    Description: The adaptive Rothe method approaches a time-dependent PDE as an ODE in function space. This ODE is solved {\em virtually} using an adaptive state-of-the-art integrator. The {\em actual} realization of each time-step requires the numerical solution of an elliptic boundary value problem, thus {\em perturbing} the virtual function space method. The admissible size of that perturbation can be computed {\em a priori} and is prescribed as a tolerance to an adaptive multilevel finite element code, which provides each time-step with an individually adapted spatial mesh. In this way, the method avoids the well-known difficulties of the method of lines in higher space dimensions. During the last few years the adaptive Rothe method has been applied successfully to various problems with infinite speed of propagation of information. The present study concerns the adaptive Rothe method for hyperbolic equations in the model situation of the wave equation. All steps of the construction are given in detail and a numerical example (diffraction at a corner) is provided for the 2D wave equation. This example clearly indicates that the adaptive Rothe method is appropriate for problems which can generally benefit from mesh adaptation. This should be even more pronounced in the 3D case because of the strong Huygens' principle.
    Keywords: ddc:000
    Language: English
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    Solving moving boundary problems with an adaptive moving grid method: Rotary heat exchangers with condensation and evaporation (1996)
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    Publication Date: 2014-02-26
    Description: A numerical method for the treatment of moving discontinuities in the model equations of chemical engineering systems is presented. The derived model describing the effects of condensation and evaporation in a regenerative air to air heat exchanger yields an illustrative example for these so called moving boundary problems. The presented adaptive moving grid method is based on the algorithm {\sc Pdex} for parabolic partial differential equations. It is shown that the method is suited for problems where the arising discontinuities cause low rates of convergence if the equations are solved with a static grid.
    Keywords: ddc:000
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    Harvesting Mathematics (1996)
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    Publication Date: 2014-02-26
    Description: Nahezu flächendeckend sind die mathematischen Fachbereiche der BRD zum Jahresende '95 im WWW vertreten. Durch die relative hohe Zahl von Servern entstehen Schwierigkeiten bei der Sichtung der angebotenen Information. Wir besprechen "Harvest" als brauchbares und gebrauchsfähiges Hilfsmittel zur Dokumentation.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
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  • 36
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    DMV-Vorhaben. "Verbesserung des benutzerorientierten Zugriffs auf fachspezifische Online-Datenbanken und CD-ROM für Mathematische Institute der Bundesrepublik Deutschland" (1996)
    Details
    Publication Date: 2014-02-26
    Description: Der Report analysiert die Ergebnisse des Projektes ,,Verbesserung des benutzerorientierten Zugriffs auf fachspezifische Online und CD-ROM Datenbanken für Mathematische Institute der Bundesrepublik Deutschland'' der Deutschen Mathematiker-Vereinigung. An dem Projekt, das vom ZIB geleitet und koordiniert worden ist, haben mehr als 50 mathematische Fachbereiche und Forschungsinstitute teilgenommen. Dieses vom damaligen BMFT (einem Teil des jetzigen Bundesministeriums für Bildung, Wissenschaft, Forschung und Technologie) geförderte Projekt hat wesentlich dazu beigetragen, dass fachspezifische Datenbanken heute in den mathematischen Fachbereichen in Deutschland zu den selbstverständlichen Arbeitsmitteln gehören. Darüber hinaus hat das Projekt die Grundlagen für eine moderne elektronische Informations- und Kommunikationsstruktur in den mathematischen Fachbereichen gelegt.
    Keywords: ddc:000
    Language: German
    Type: reportzib , doc-type:preprint
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    Handbuch der Berliner Software Distribution (BeSD) (1996)
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    Publication Date: 2014-02-26
    Description: Dieser Report beschreibt ein Konzept zur einheitlichen Bereitstellung von Software in heterogenen Umgebungen. Software kann so kooperativ durch mehrere Beteiligten (z. B. auch über Institutsgrenzen hinweg) angeboten und genutzt werden. Die Konzepte stammen ursprünglich vom Rechenzentrum der Universität Stuttgart (RUS) und wurden im Rahmen eines vom Verein zur Förderung eines Deutschen Forschungsnetzes (DFN) mit Mitteln des BMBF geförderten Projekts zur Berliner Software Distribution (BeSD) weiterentwickelt.
    Keywords: ddc:000
    Language: German
    Type: reportzib , doc-type:preprint
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    Hamiltonian Path Problems in the On-line Optimization of Flexible Manufacturing Systems (1996)
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    Publication Date: 2014-02-27
    Description: In this thesis we describe a practical problem that we encountered in the on--line optimization of a complex Flexible Manufacturing System. In the considered system a stacker crane has to fulfill all transportation tasks (jobs) in a single aisled automatic storage system. The jobs have to be sequenced in such a way, that the time needed for the unloaded moves is minimized. The modelling of this question leads to the so--called on--line Hamiltonian path problem. We computationally compare several on--line heuristics and derive lower bounds on the value obtained by an optimal on--line strategy by analyzing two off--line Combinatorial Optimization problems: the asymmetric Hamiltonian path problem with precedence constraints, also called sequential ordering problem (SOP), and the asymmetric Hamiltonian path problem with time windows (AHPPTW). We study the SOP and AHPPTW from a polyhedral point of view and derive several new classes of valid inequalities. Based on the polyhedral investigations we develop branch&cut algorithms for both problems and can achieve encouraging results on solving problem instances from real--world examples of the practical application.
    Keywords: ddc:000
    Language: English
    Type: doctoralthesis , doc-type:doctoralThesis
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    Wissenschaftliche Information und Kommunikation im Umbruch (1996)
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    Publication Date: 2014-02-26
    Description: Steht uns das Ende des traditionellen wissenschaftlichen Publizierens bevor? Neue Technologien eröffnen neue Chancen zur Bewältigung der Informationsflut und des gleichzeitigen Informationsmangels. Doch der Einsatz von Technik allein reicht nicht aus.
    Keywords: ddc:000
    Language: German
    Type: reportzib , doc-type:preprint
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  • 40
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    Neue Produkte für die digitale Bibliothek: die Rolle der Wissenschaften (1996)
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    Publication Date: 2014-02-26
    Description: Der Artikel ist die ausgearbeitete und erweiterte Fassung eines eingeladenen Vortrags der Tagung ,,Die unendliche Bibliothek - Digitale Information in Wissenschaft, Verlag und Bibliothek''. Dieses Treffen, eine Veranstaltung des Börsenvereins des Deutschen Buchhandels e.V., der Deutschen Bibliothek und der Bundesvereinigung Deutscher Bibliothkesverbände, fand im Dezember 1995 in Bonn als Beitrag zur der heute aktuellen Debatte unter Wissenschaftlern, Verlegern, Buchhändlern, Bibliothekaren und Politikern statt, wie unser Wissen und unsere Informationen digital transferiert werden können. Der Vortrag stellte das zentrale Problem des heutigen wissenschaftlichen Informationswesens dar, die gleichzeitige Existenz von Informationsflut und Informationsmangel. Nach einer knappen Bestimmung der Veränderung der Kommunikationsstrukturen in den Wissenschaften fragte er nach den essentiellen Veränderungen der Informationsarten, d.h. nach der Natur der kommenden Globalen Digitalen Bibliothek, die als ein über die ganze Welt und auf viele Institutionen verteilter globaler Speicher gesehen wird. Der Vortrag diskutierte zum Schluss die Bedürfnisse und Interessen der Wissenschaften und ihre spezifische Verantwortung beim Übergang in die elektronische Welt. Der Tagungsband ist erschienen beim Harrassowitz Verlag, Wiesbaden, 1996.
    Keywords: ddc:000
    Language: German
    Type: reportzib , doc-type:preprint
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    On Changing Patterns of Mathematical Communication. Breakdowns in Traditional Publication (1996)
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    Publication Date: 2018-02-27
    Description: The Internet and the new electronic means of information and communication are transforming scientific communication fundamentally. In particular, mathematicians, physicists and other natural scientists intensify, accelerate and extend their communication by the use of the Internet and its tools, from electronic mail up to the World Wide Web. In doing so, they also exchange scientific results of a new kind and quality yet unknown to traditional information providers such as publishers, libraries, and database suppliers (e.g. in the form of current research software, scientific data collections, observations and experimental data, visualizations, animations etc.). They, on the other hand, perceive the new ways, which are passing their own field of activity, as breakdowns of traditional publishing, as it was termed by the Association of Computing Machinery. In addition, scientific libraries find themselves caught in a structural crisis -- not only because of budget restraints. The {\it Deutsche Mathematiker-Vereinigung} (DMV), however, sees the new electronic means as an opportunity to master a crisis of this kind rather than a threat. By discussing concrete models, which may be - in a certain technical sense -- realizable already today, the article gives an introduction into the subject of a {\it Distributed Information- and Communication System for Mathematics}, a project prepared and planned by the DMV for the years 1996 to 1998. In the context of possible realization variants it also deals with questions of costs, resulting load of network connections, and -- showing the beginnings -- the (absolutely essential) solution of problems related to quality, authenticity, archival and intellectual property rights, which arise with the employment of electronic means. Obviously (even if not discussed explicitly) also computing centers, whose tasks and position are also affected by the electronic revolution, have the chance to find a new and forward-looking role in this field - in particular by new forms of cooperation with scientific libraries.
    Keywords: ddc:000
    Language: English
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    Netzverteilte Visualisierung und Simulation (1996)
    Details
    Publication Date: 2021-01-22
    Description: Dieser Bericht beschreibt die Ergebnisse eines Anwendungsprojektes, das parallel zum Aufbau des Berliner Hochgeschwindigkeitsdatennetzes (Berlin Regional Testbed) am ZIB durchgeführt wurde. Es werden allgemeine Werkzeuge und anwendungsspezifische Arbeitsumgebungen zur netzverteilten Visualisierung und Simulation vorgestellt. Die allgemeinen Werkzeuge unterstützen folgende Aufgaben: Kopplung von Simulationen auf (Hochleistungs-)Rechnern an lokale Grafikarbeitsplätze, objektorientierte und verteilte Visualisierung, Remote-Videoaufzeichnung, Bilddatenkompression und digitaler Filmschnitt. Die spezifischen Arbeitsumgebungen wurden für Aufgaben aus den Bereichen Numerische Mathematik, Astrophysik, Strukturforschung, Chemie, Polymerphysik und Strömungsmechanik entwickelt.
    Keywords: ddc:000
    Language: German
    Type: reportzib , doc-type:preprint
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  • 43
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    ZGUI-Handbuch (1996)
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    Publication Date: 2014-03-06
    Description: In diesem Handbuch werden die Bausteine zum Aufbau einer graphischen Benutzeroberfläche mit {\tt ZGUI} beschrieben. Auf der einen Seite stehen die Tcl/Tk--Prozeduren, die die graphischen Elemente definieren. Die Beschreibung der Anwendung der Prozeduren und der Interaktionen der Elemente bildet den ersten Teil des Handbuches. Auf der anderen Seite stehen die Anforderungen an Anwendungen, die mit einer {\tt ZGUI}--Benutzeroberlfäche gesteuert werden sollen. Hier findet man im Handbuch die Beschreibung der Anwendungsprogrammierschnittstelle (application programming interface, API).
    Keywords: ddc:000
    Language: German
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  • 44
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    Neueste Entwicklungen der Informations- und Kommunikationstechnik und ihre Auswirkungen auf den Wissenschaftsbetrieb (1996)
    Details
    Publication Date: 2014-02-26
    Description: Dieser Aufsatz ist die Ausarbeitung eines Vortrags auf der 4. Jahrestagung der Gesellschaft Information Bildung (GIB) am 10. und 11. Oktober 1996 an der Humboldt-Universität Berlin. Er enthält einen Überblick über die neuesten Entwicklungen in der Informations- und Kommunikationstechnik und beleuchtet deren Auswirkungen auf den Wissenschaftsbetrieb. Er beginnt mit historischen Anmerkungen zur Entstehung der Schrift und zur Speicherung und Übertragung von Information. Er führt, nach einer knappen Diskussion der Defizite in der gegenwärtigen Informationsversorgung und einem kurzen Ausflug in die Geschichte des Internet und des World Wide Web, zu einer Darstellung ausgewählter aktueller Aktivitäten der Wissenschaften im Bereich elektronischer Information, Kommunikation, Dokumentation und Archivierung. Dabei zeigt sich, dass sich der Begriff wissenschaftlicher Information bereits zu wandeln beginnt. Zur traditionellen papiergebundenen Information treten völlig neue Informationsarten hinzu, von Software- und Datensammlungen über multimediale Information bis hin zu Fernübertagungen von wissenschaftlichen Vorträgen und Experimenten. Eine Vielzahl von Links; (URL's bzw. anklickbaren Verweisen) soll diesen Wandel nicht nur belegen, sondern auch das rasche Auffinden wichtiger Dokumente und Quellen im Internet ermöglichen.
    Keywords: ddc:000
    Language: German
    Type: reportzib , doc-type:preprint
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    Paralleler und Objektorientierter Simplex (1996)
    Details
    Publication Date: 2014-02-27
    Description: {\footnotesize In der vorliegenden Arbeit werden neue Implementierungen des dualen und primalen revidierten Simplex-Algorithmus für die Lösung linearer Programme (LPs) vorgestellt. Dazu werden die Algorithmen mithilfe einer Zeilenbasis dargestellt, aus der über einen Spezialfall die übliche Darstellung mit einer Spaltenbasis folgt. Beide Darstellungen sind über die Dualität eng miteinander verbunden. Ausserdem wird eine theoretische Untersuchung der numerischen Stabilität von Simplex-Algorithmen durchgeführt, und es werden verschiedene Möglichkeiten der Stabilisierung diskutiert. Beide Darstellungen der Basis werden in den Implementierungen algorithmisch ausgenutzt, wobei der Einsatz der Zeilenbasis für LPs mit mehr Nebenbedingungen als Variablen Geschwindigkeitsvorteile bringt. Darüberhinaus werden weitere Beschleunigung gegenüber anderen state-of-the-art Implentierungen erzielt, und zwar durch den Einsatz eines Phase-1 LPs, das eine grösstmögliche Übereinstimmung mit dem Ausgangs-LPs aufweist, durch eine dynamische Anpassung der Faktorisierungsfrequenz für die Basis-Matrix und durch die Optimierung der Lösung linearer Gleichungssysteme für besonders dünnbesetzte Matrizen und Vektoren. Es wurden drei Implementierungen vorgenommen. Die erste läuft sequentiell auf einem PC oder einer Workstation. Ihre hohe numerische Stabilität und Effizienz durch die Integration der oben genannten Konzepte machen sie zu einem zuverlässigen Hilfsmittel für den täglichen Einsatz z.B.~in Schnittebenenverfahren zur Lösung ganzzahliger Programme. Als Programmiersprache wurde C++ verwendet, und es wurde ein objektorientierter Software-Entwurf zugrundegelegt. Dieser leistet eine hohe Flexibilität und Anpassbarkeit z.B.~für die Integration benutzerdefinierter Pricing-Strategien. Bei den anderen beiden Implentierungen handelt es sich um parallele Versionen für Parallelrechner mit gemeinsamem und für solche mit verteiltem Speicher. Dabei wird der objektorientierte Entwurf so genutzt, dass lediglich die zusätzlichen Aufgaben für die Parallelisierung (Synchronisation, Kommunikation und Verteilung der Arbeit) implementiert werden, während alle Algorithmen von der sequentiellen Implementierung geerbt werden. Die Parallelisierung setzt an vier Punkten an. Der erste und einfachste ist die parallele Berechnung eines Matrix-Vektor-Produktes. Als zweites wurden beim Pricing und Quotiententest parallele Suchalgorithmen eingesetzt. Weiter werden beim steepest-edge Pricing zwei lineare Gleichungssysteme nebenläufig gelöst. Schliesslich wird ein paralleles Block-Pivoting verwendet, bei dem Gleichungssysteme mehrerer aufeinanderfolgender Iterationen gleichzeitig gelöst werden. Ob und welche der Parallelisierungs-Konzepte eine Beschleunigung bewirken, ist problemabhängig. Es gelingt z.B.~mit 32 Prozessoren eine Beschleunigung um mehr als einen Faktor 16 zu erzielen. Schliesslich wird die parallele Lösung dünnbesetzter linearer Gleichungssysteme mit unsymmetrischen Matrizen untersucht und eine Implementierung für den Cray T3D vorgenommen. Sie enthält ein neues Verfahren des Lastausgleichs, das keinen zusätzlichen Aufwand verursacht. Die Implementierung erzielt vergleichsweise günstige Laufzeiten.}
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    Language: German
    Type: doctoralthesis , doc-type:doctoralThesis
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    Highly scalable parallel linearly-implicit extrapolation algorithms (1996)
    Details
    Publication Date: 2014-02-26
    Description: We present parallel formulations of the well established extrapolation algorithms EULSIM and LIMEX and its implementation on a distributed memory architecture. The discretization of partial differential equations by the method of lines yields large banded systems, which can be efficiently solved in parallel only by iterative methods. Polynomial preconditioning with a Neumann series expansion combined with an overlapping domain decomposition appears as a very efficient, robust and highly scalable preconditioner for different iterative solvers. A further advantage of this preconditioner is that all computation can be restricted to the overlap region as long as the subdomain problems are solved exactly. With this approach the iterative algorithms operate on very short vectors, the length of the vectors depends only on the number of gridpoints in the overlap region and the number of processors, but not on the size of the linear system. As the most reliable and fast iterative methods based on this preconditioning scheme appeared GMRES or FOM and BICGSTAB. To further reduce the number of iterations in GMRES or FOM we can reuse the Krylov-spaces constructed in preceeding extrapolation steps. The implementation of the method within the program LIMEX results in a highly parallel and scalable program for solving differential algebraic problems getting an almost linear speedup up to 64 processors even for medium size problems. Results are presented for a difficult application from chemical engineering simulating the formation of aerosols in industrial gas exhaust purification.
    Keywords: ddc:000
    Language: English
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    The cascadic multigrid method for elliptic problems (1996)
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    Publication Date: 2020-05-04
    Language: English
    Type: article , doc-type:article
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  • 48
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    Cascadic Multigrid Methods (1996)
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    Publication Date: 2020-12-15
    Language: English
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    Dynamic dimension reduction in ODE models (1996)
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    Publication Date: 2020-09-25
    Language: English
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  • 50
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    Towards Dynamic Dimension Reduction in Reactive Flow Problems (1996)
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    Publication Date: 2020-11-16
    Language: English
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    Recent Progress in Dynamical Process Simulation (1996)
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    Publication Date: 2020-12-14
    Language: English
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  • 52
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    An adaptive Galerkin method for the PDF transport equation of turbulent reactive flows (1996)
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    Publication Date: 2020-09-24
    Language: English
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  • 53
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    Eine graphische Oberfläche für numerische Programme (1996)
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    Publication Date: 2021-01-21
    Language: English
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  • 54
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    Formale Spezifikation des ZIB-GUI mit Hilfe von Graph-Grammatiken (1996)
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    Publication Date: 2021-01-21
    Language: English
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  • 55
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    A Volume-Surface Integral Method for Solving Maxwell’s Equations in Electrically Inhomogeneous Media Using Tetrahedral Grids (1996)
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    Publication Date: 2021-03-16
    Language: English
    Type: article , doc-type:article
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  • 56
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    Simulation Studies for Combination of Hyperthermia and Magnetic Resonance Systems (1996)
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    Publication Date: 2021-03-16
    Language: English
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  • 57
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    Three-Dimensional Finite Element Mesh Generation for Numerical Simulations of Hyperthermia Treatments (1996)
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    Publication Date: 2021-03-16
    Language: English
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    HyperPlan - an integrated system for treatment planning in regional hyperthermia (1996)
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    Publication Date: 2021-03-16
    Language: English
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    Simulation studies promote technological development of radiofrequency phased array hyperthermia (1996)
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    Publication Date: 2021-03-16
    Language: English
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    Modellierung von Einleitungen in kleine Fließgewässer (1996)
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    Publication Date: 2020-03-20
    Language: English
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    Feature article - The Simulation of Molecular Weight Distributions in Polyreaction Kinetics by Discrete Galerkin Methods (1996)
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    Publication Date: 2020-03-20
    Language: English
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    Stable-Set and Other Techniques for Frequency Assignment Problems (1996)
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    Publication Date: 2020-08-05
    Language: English
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    Den Kohl heile rüberbringen … – Mathematische Methoden der Transportoptimierung (1996)
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    Publication Date: 2020-08-05
    Language: English
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    Neue Produkte für die digitale Bibliothek (1996)
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    Publication Date: 2020-08-05
    Language: English
    Type: bookpart , doc-type:bookPart
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    Wissenschaftliche Information und Kommunikation im Umbruch (1996)
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    Publication Date: 2020-08-05
    Language: English
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    Optimum Path Packing on Wheels (1996)
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    Publication Date: 2020-08-05
    Language: English
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  • 67
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    Packing Steiner Trees: Separation Algorithms (1996)
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    Publication Date: 2020-08-05
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  • 68
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    Packing Steiner Trees: Further Facets (1996)
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    Publication Date: 2020-08-05
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  • 69
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    Packing Steiner trees: Polyhedral Investigations (1996)
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    Publication Date: 2020-08-05
    Language: English
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  • 70
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    Packing Steiner trees: a cutting plane algorithm and computational results (1996)
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    Publication Date: 2020-08-05
    Language: English
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  • 71
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    A Semidefinite Programming Approach to the Quadratic Knapsack Problem (1996)
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    Publication Date: 2014-02-26
    Description: We investigate dominance relations between basic semidefinite relaxations and classes of cuts. We show that simple semidefinite relaxations are tighter than corresponding linear relaxations even in case of linear cost functions. Numerical results are presented illustrating the quality of these relaxations.
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  • 72
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    Computation of Decaying Turbulence in an Adaptive Wavelet Basis (1996)
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    Publication Date: 2014-02-26
    Description: The paper presents computations of decaying two--dimensional turbulence in an adaptive wavelet basis. At each time step the vorticity is represented by an adaptively selected set of wavelet functions which adjusts to the instantaneous distribution of vorticity. The results of this new algorithm are compared to a classical Fourier method and a Fourier method supplemented with wavelet compression in each time step.
    Keywords: ddc:000
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  • 73
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    On Hilbert bases of polyhedral cones (1996)
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    Publication Date: 2014-02-26
    Description: For a polyhedral cone $C=$ pos $\{a^1,\dots,a^m\}\subset R^d$, $a^i\in Z^d$, a subset of integral vectors $H(C)\subset C \cap Z^d$ is called a Hilbert basis of $C$ iff (i) each element of $C\cap Z^d$ can be written as a non-negative integer combination of elements of $H(C)$ and (ii) $H(C)$ has minimal cardinality with respect to all subsets of $C \cap Z^d$ for which (i) holds. We show that various problems related to Hilbert bases are hard in terms of computational complexity. However, if the dimension and the number of elements of the Hilbert basis are fixed, a Hilbert basis can always be computed in polynomial time. Furthermore we introduce a (practical) algorithm for computing the Hilbert basis of a polyhedral cone. The finiteness of this method is deduced from a result about the height of a Hilbert basis which, in particular, improves on former estimates.
    Keywords: ddc:000
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  • 74
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    Spherically symmetric perfect fluids in shearfree motion - the symmetry approach (1996)
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    Publication Date: 2014-02-26
    Description: In General Relativity, the motion of expanding shearfree perfect fluids is governed by the ordinary differential equation $y^{\prime \prime }=$ $% F(x)\,y^2$ , where $F$ is an arbitrary function from which the equation of state can be computed. A complete symmetry analysis of this differential equation is given; its solutions are classified according to this scheme, and in particular the relation to Wyman's Painlev\'e analysis is clarified.
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    Eine graphische Oberfläche für numerische Programme (1996)
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    Publication Date: 2014-03-06
    Description: Der Entwurf und die Implementierung des auf Tcl/Tk basierenden Werkzeugkastens ZGUI wird beschrieben und an einigen Beispielen erläutert. ZGUI unterstützt die Entwicklung einer graphischen Benutzeroberfläche (GUI) für die am ZIB erstellte numerische Software. Es sollen folgende Ziele erreicht werden: \begin{itemize} \item einfaches Ausprobieren anhand vordefinierter Testprobleme,\vspace*{-2mm} \item Kennenlernen numerischer Steuergrö\ss en und Verfahrensvarianten,\vspace*{-2mm} \item einfache Eingabe neuer Probleme,\vspace*{-2mm} \item einfache Nutzung graphischer Ausgabemöglichkeiten und\vspace*{-2mm} \item einheitliche Darstellung gleicher oder ähnlicher Optionen. \end{itemize}
    Keywords: ddc:000
    Language: German
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    Seeking the Equation of State of Non-Compact Lattice QED (1996)
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    Publication Date: 2020-12-15
    Description: We perform a high statistics calculation of the equation of state for non-compact QED on large lattices. The calculation extends to fermionic correlation lengths of $\approx 8$, and it is combined with a finite size scaling analysis of the lattice data.
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    Language: English
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  • 77
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    On Robust Multigrid Methods for Piecewise Smooth Variational Problems (1996)
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    Publication Date: 2014-02-26
    Description: We consider the fast solution of large, piecewise smooth minimization problems as resulting from the approximation of elliptic free boundary problems. The most delicate question in constructing a multigrid method for a nonlinear, non--smooth problem is how to represent the nonlinearity on the coarse grids. This process usually involves some kind of linearization. The basic idea of monotone multigrid methods to be presented here is first to select a neighborhood of the actual smoothed iterate in which a linearization is possible and then to constrain the coarse grid correction to this neighborhood. Such a local linearization allows to control the local corrections at each coarse grid node in such a way that the energy functional is monotonically decreasing. This approach leads to globally convergent schemes which are robust with respect to local singularities of the given problem. The numerical performance is illustrated by approximating the well-known Barenblatt solution of the porous medium equation.
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  • 78
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    Note on lattice-point-free convex bodies (1996)
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    Publication Date: 2014-02-26
    Description: We prove inequalities relating the inradius of a convex body with interior containing no point of the integral lattice, with the volume or surface area of the body. These inequalities are tight and generalize previous results.
    Keywords: ddc:000
    Language: English
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    Optimale Blockauswahl bei der Kraftwerkseinsatzplanung (1996)
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    Publication Date: 2014-02-26
    Description: The paper addresses the unit commitment problem in power plant operation planning. For a real power system comprising coal and gas fired thermal as well as pumped storage hydro plants a large-scale mixed integer optimization model for unit commitment is developed. Then primal and dual approaches to solving the optimization problem are presented and results of test runs are reported.
    Keywords: ddc:000
    Language: German
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    Visualization of Vector Fields in Quantum Chemistry (1996)
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    Publication Date: 2014-02-26
    Description: \small Many interesting phenomena in molecular systems like interactions between macro-molecules, protein-substrate docking, or channeling processes in membranes are gouverned to a high degree by classical Coulomb or van-der-Waals forces. The visualization of these force fields is important for verifying numerical simulations. Moreover, by inspecting the forces visually we can gain deeper insight into the molecular processes. Up to now the visualization of vector fields is quite unusual in computational chemistry. In fact many commercial software packages do not support this topic at all. The reason is not that vector fields are considered unimportant, but mainly because of the lack of adequate visualization methods. In this paper we survey a number of methods for vector field visualization, ranging from well-known concepts like arrow or streamline plots to more advanced techniques like line integral convolution, and show how these can be applied to computational chemistry. A combination of the most meaningful methods in an interactive 3D visualization environment can provide a powerful tool box for analysing simulations in molecular dynamics.
    Keywords: ddc:000
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    Smoothed Langevin dynamics of highly oscillatory systems (1996)
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    Publication Date: 2014-02-26
    Description: In this paper we generalize a result by Rubin and Ungar on Hamiltonian systems containing a strong constraining potential to Langevin dynamics. Such highly oscillatory systems arise, for example, in the context of molecular dynamics. We derive constrained equations of motion for the slowly varying solution components. This includes in particular the derivation of a correcting force-term that stands for the coupling of the slow and fast degrees of motion. We will identify two limiting cases: (i) the correcting force becomes, over a finite interval of time, almost identical to the force term suggested by Rubin and Ungar (weak thermal coupling) and (ii) the correcting force can be approximated by the gradient of the Fixman potential as used in statistical mechanics (strong thermal coupling). The discussion will shed some light on the question which of the two correcting potentials is more appropriate under which circumstances for molecular dynamics. In Sec.~7, we also discuss smoothing in the context of constant temperature molecular dynamics.
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    On the Approximation of Complicated Dynamical Behavior (1996)
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    Publication Date: 2014-02-26
    Description: We present efficient techniques for the numerical approximation of complicated dynamical behavior. In particular, we develop numerical methods which allow to approximate SBR-measures as well as (almost) cyclic behavior of a dynamical system. The methods are based on an appropriate discretization of the Frobenius-Perron operator, and two essentially different mathematical concepts are used: the idea is to combine classical convergence results for finite dimensional approximations of compact operators with results from Ergodic Theory concerning the approximation of SBR-measures by invariant measures of stochastically perturbed systems. The efficiency of the methods is illustrated by several numerical examples.
    Keywords: ddc:000
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    Selfadaptive Finite Element Computations with Smooth Time Controller and Anisotropic Refinement (1996)
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    Publication Date: 2014-02-26
    Description: We present Multilevel Finite Element computations for twodimensional reaction-diffusion systems modelling laminar flames. These systems are prototypes for extreme stiffness in time and space. The first of these two rather general features is accounted for by an improved control mechanism for the time step. The second one is reflected through very thin travelling reaction fronts for which we propose an anisotropic discretization by local directional refinement.
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    An Efficient Storage Scheme for Reduced Chemical Kinetics Based on Orthogonal Polynomials (1996)
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    Publication Date: 2014-02-26
    Description: Simplified chemical kinetic schemes are a crucial prerequisite for the simulation of complex three-dimensional turbulent flows, and various methods for the generation of reduced mechanisms have been developed in the past. The method of intrinsic low-dimensional manifolds (ILDM), e.g., provides a mathematical tool for the automatic simplification of chemical kinetics, but one problem of this method is the fact that the information which comes out of the mechanism reduction procedure has to be stored for subsequent use in reacting flow calculations. In most cases tabulation procedures are used which store the relevant data (such as reduced reaction rates) in terms of the reaction progress variables, followed by table look-up during the reacting flow calculations. This can result in huge amounts of storage needed for the multi-dimensional tabulation. In order to overcome this problem we present a storage scheme which is based on orthogonal polynomials. Instead of using small tabulation cells and local mesh refinement, the thermochemical state space is divided into a small number of coarse cells. Within these coarse cells polynomial approximations are used instead of frequently used multi-linear interpolation. This leads to a considerable decrease of needed storage. The hydrogen-oxygen system is considered as an example. Even for this small chemical system we obtain a decrease of the needed storage requirement by a factor of 100.
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    Adaptive Accuracy Control for Microcanonical Car-Parrinello Simulations (1996)
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    Publication Date: 2014-02-26
    Description: The Car-Parrinello (CP) approach to ab initio molecular dynamics serves as an approximation to time-dependent Born-Oppenheimer (BO) calculations. It replaces the explicit minimization of the energy functional by a fictitious Newtonian dynamics and therefore introduces an artificial mass parameter $\mu$ which controls the electronic motion. A recent theoretical investigation shows that the CP-error, i.e., the deviation of the CP--solution from the BO-solution {\em decreases} like $\mu^{1/2}$ asymptotically. Since the computational effort {\em increases} like $\mu^{-1/2}$, the choice of $\mu$ has to find a compromise between efficiency and accuracy. The asymptotical result is used in this paper to construct an easily implemented algorithm which automatically controls $\mu$: the parameter $\mu$ is repeatedly adapted during the simulation by choosing $\mu$ as large as possible while pushing an error measure below a user-given tolerance. The performance and reliability of the algorithm is illustrated by a typical example.
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    A Mathematical Investigation of the Car-Parrinello Method (1996)
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    Publication Date: 2014-02-26
    Description: The Car-Parrinello method for ab-initio molecular dynamics avoids the explicit minimization of energy functionals given by functional density theory in the context of the quantum adiabatic approximation (time-dependent Born-Oppenheimer approximation). Instead, it introduces a fictitious classical dynamics for the electronic orbitals. For many realistic systems this concept allowed first-principle computer simulations for the first time. In this paper we study the {\em quantitative} influence of the involved parameter $\mu$, the fictitious electronic mass of the method. In particular, we prove by use of a carefully chosen two-time-scale asymptotics that the deviation of the Car-Parrinello method from the adiabatic model is of order ${\rm O}(\mu^{1/2})$ --- provided one starts in the ground state of the electronic system and the electronic excitation spectrum satisfies a certain non-degeneracy condition. Analyzing a two-level model problem we prove that our result cannot be improved in general. Finally, we show how to use the gained quantitative insight for an automatic control of the unphysical ``fake'' kinetic energy of the method.
    Keywords: ddc:000
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    Backward Error Analysis for Numerical Integrators (1996)
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    Publication Date: 2014-02-26
    Description: We consider backward error analysis of numerical approximations to ordinary differential equations, i.e., the numerical solution is formally interpreted as the exact solution of a modified differential equation. A simple recursive definition of the modified equation is stated. This recursion is used to give a new proof of the exponentially closeness of the numerical solutions and the solutions to an appropriate truncation of the modified equation. We also discuss qualitative properties of the modified equation and apply these results to the symplectic variable step-size integration of Hamiltonian systems, the conservation of adiabatic invariants, and numerical chaos associated to homoclinic orbits.
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    Lagrangean Relaxations and Subgradient Methods for Multiple-Depot Vehicle Scheduling Problems (1996)
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    Publication Date: 2014-11-02
    Description: This paper presents two Lagrangean relaxation approaches for the {\em NP}-hard multiple-depot vehicle scheduling problem in public mass transit and reports on computational investigations. Our Lagrangean relaxation approaches can be applied to generate very tight lower bounds and to compute feasible solutions efficiently. A further application is to use the Lagrangean relaxations as new pricing strategies for a delayed column generation of a branch-and-cut approach. The computational investigations are based on real-world test sets from the cities of Berlin and Hamburg having up to 25 thousand timetabled trips and 70 million dead-head trips.
    Keywords: ddc:000
    Language: English
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    Gröbner Bases and Triangles (1996)
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    Publication Date: 2015-06-01
    Description: It is well-known that by polynomial elimination methods, in particular by the computation of Gröbner bases, proofs for geometric theorems can be automatically generated. %% Several monographs On the other hand, it is much less known that Gröbner bases, in combination with rational factorization, can be even used to {\sl find} new geometric theorems. In this article such a method is described, and some new theorems on plane triangles are deduced.
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    Algorithms for Classical Orthogonal Polynomials (1996)
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    Publication Date: 2015-06-01
    Description: \begin{enumerate} \item[] {{\small In this article explicit formulas for the recurrence equation \[ p_{n+1}(x)=(A_n\,x+B_n)\,p_n(x)-C_n\,p_{n-1}(x) \] and the derivative rules \[ \sigma(x)\,p_n'(x)=\alpha_n\,p_{n+1}(x)+\beta_n\,p_n(x)+\gamma_n\,p_{n-1}(x) \] and \[ \sigma(x)\,p_n'(x)=(\tilde\alpha_n\,x+\tilde\beta_n)\,p_n(x)+ \tilde\gamma_n\,p_{n-1}(x) \] respectively which are valid for the orthogonal polynomial solutions $p_n(x)$ of the differential equation \[ \sigma(x)\,y''(x)+\tau(x)\,y'(x)+\lambda_n\,y(x)=0 \] of hypergeometric type are developed that depend {\sl only} on the coefficients $\sigma(x)$ and $\tau(x)$ % and $\lambda_n$ which themselves are polynomials w.r.t.\ $x$ of degrees not larger than $2$ and $1$% and $0$ , respectively. Partial solutions of this problem had been previously published by Tricomi, and recently by Y\'a\~nez, Dehesa and Nikiforov. Our formulas yield an algorithm with which it can be decided whether a given holonomic recurrence equation (i.e.\ one with polynomial coefficients) generates a family of classical orthogonal polynomials, and returns the corresponding data (density function, interval) including the standardization data in the affirmative case. In a similar way, explicit formulas for the coefficients of the recurrence equation and the difference rule \[ \sigma(x)\,\nabla p_n(x)= \alpha_n\,p_{n+1}(x)+\beta_n\,p_n(x)+\gamma_n\,p_{n-1}(x) \] of the classical orthogonal polynomials of a discrete variable are given that depend only on the coefficients $\sigma(x)$ and $\tau(x)$ of their difference equation \[ \sigma(x)\,\Delta\nabla y(x)+\tau(x)\,\Delta y(x)+\lambda_n\,y(x)=0 \;. \] Here \[ \Delta y(x)=y(x+1)-y(x) \quad\quad\mbox{and}\quad\quad \nabla y(x)=y(x)-y(x-1) \] denote the forward and backward difference operators, respectively. In particular this solves the corresponding inverse problem to find the classical discrete orthogonal polynomial solutions of a given holonomic recurrence equation. \iffalse Furthermore, an algorithmic approach to deduce these and similar properties is presented which is implementable in computer algebra, and which moreover generates relations between different standardizations of the polynomial system considered. \fi }} \end{enumerate}
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    Towards Dynamical Dimension Reduction in Reactive Flow Problems (1996)
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    Publication Date: 2014-02-26
    Description: The paper addresses the possibilities of reducing the overall number of degrees of freedom in large scale reactive flow computations. Attention focusses on the dimension reduction technique ILDM due to {\sc Maas and Pope}, which treats certain automatically detected fast dynamic components as algebraic equations (so-called slow manifold). In earlier papers, the dimension of the reduction had been kept constant throughout each computation. Recently, a mathematically sound and nevertheless cheap dimension monitor for the chemistry part only has been suggested by {\sc Deuflhard and Heroth}. The present paper reports about first steps taken towards the implementation of that monitor into a flame code. Moreover, a sparse grid storage scheme is advocated and analyzed in view of the construction of efficient table look--ups for nested manifolds.
    Keywords: ddc:000
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    Classical and Cascadic Multigrid - A Methodical Comparison (1996)
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    Publication Date: 2020-11-13
    Description: Using the full multigrid method {\em without} any coarse grid correction steps but with an a posteriori control of the number of smoothing iterations was shown by Bornemann and Deuflhard [1996] to be an optimal iteration method with respect to the energy norm. They named this new kind of multigrid iteration the {\em cascadic multigrid method}. However, numerical examples with {\em linear} finite elements raised serious doubts whether the cascadic multigrid method can be made optimal with respect to the {\em $L^2$-norm}. In this paper we prove that the cascadic multigrid method cannot be optimal for linear finite elements and show that the case might be different for higher order elements. We present a careful analysis of the two grid variant of the cascadic multigrid method providing a setting where one can understand the methodical difference between the cascadic multigrid method and the classical multigrid $V$-cycle almost immediately. As a rule of thumb we get that whenever the cascadic multigrid works the classical multigrid will work too but not vice versa.
    Keywords: ddc:000
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    Adaptive FEM for Reaction-Diffusion Equations (1996)
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    Publication Date: 2014-02-26
    Description: An integrated time--space adaptive finite element method for solving mixed systems of nonlinear parabolic, elliptic, and differential algebraic equations is presented. The approach is independent of the spatial dimension. For the discretization in time we use singly diagonally linearly implicit Runge--Kutta methods of Rosenbrock type. Local time errors for the step size control are defined by an embedded strategy. A multilevel finite element Galerkin method is subsequently applied for the discretization in space. A posteriori estimates of local spatial discretization errors are obtained solving local problems with higher order approximation. Superconvergence arguments allow to simplify the required computations. Two different strategies to obtain the start grid of the multilevel process are compared. The devised method is applied to a solid--solid combustion problem.
    Keywords: ddc:000
    Language: English
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  • 94
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    Vehicle Scheduling in Public Transit and Lagrangean Pricing (1996)
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    Publication Date: 2014-11-02
    Description: This paper investigates the solution of the linear programming (LP) relaxation of the multicommodity flow formulation of the multiple-depot vehicle scheduling problems arising in public mass transit. We develop a column generation technique that makes it possible to solve the huge linear programs that come up there. The technique, which we call {\em Lagrangean pricing}, is based on two different Lagrangean relaxations. We describe in detail the basic ingredients of our approach and give computational results for large-scale test data (with up to 70 million variables) from three German public transportation companies. Because of these results, we propose Lagrangean pricing as one of the basic ingredients of an effective method to solve multiple-depot vehicle scheduling problems to proven optimality.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
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  • 95
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    Local Inexact Newton Multilevel FEM for Nonlinear Elliptic Problems (1996)
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    Publication Date: 2019-01-29
    Description: The finite element setting for nonlinear elliptic PDEs directly leads to the minimization of convex functionals. Uniform ellipticity of the underlying PDE shows up as strict convexity of the arising nonlinear functional. The paper analyzes computational variants of Newton's method for convex optimization in an affine conjugate setting, which reflects the appropriate affine transformation behavior for this class of problems. First, an affine conjugate Newton--Mysovskikh type theorem on the local quadratic convergence of the exact Newton method in Hilbert spaces is given. It can be easily extended to inexact Newton methods, where the inner iteration is only approximately solved. For fixed finite dimension, a special implementation of a Newton--PCG algorithm is worked out. In this case, the suggested monitor for the inner iteration guarantees quadratic convergence of the outer iteration. In infinite dimensional problems, the PCG method may be just formally replaced by any Galerkin method such as FEM for linear elliptic problems. Instead of the algebraic inner iteration errors we now have to control the FE discretization errors, which is a standard task performed within any adaptive multilevel method. A careful study of the information gain per computational effort leads to the result that the quadratic convergence mode of the Newton--Galerkin algorithm is the best mode for the fixed dimensional case, whereas for an adaptive variable dimensional code a special linear convergence mode of the algorithm is definitely preferable. The theoretical results are then illustrated by numerical experiments with a {\sf NEWTON--KASKADE} algorithm.
    Keywords: ddc:000
    Language: English
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  • 96
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    Homogenization Approach to Smoothed Molecular Dynamics (1996)
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    Publication Date: 2014-02-26
    Description: {\footnotesize In classical Molecular Dynamics a molecular system is modelled by classical Hamiltonian equations of motion. The potential part of the corresponding energy function of the system includes contributions of several types of atomic interaction. Among these, some interactions represent the bond structure of the molecule. Particularly these interactions lead to extremely stiff potentials which force the solution of the equations of motion to oscillate on a very small time scale. There is a strong need for eliminating the smallest time scales because they are a severe restriction for numerical long-term simulations of macromolecules. This leads to the idea of just freezing the high frequency degrees of freedom (bond stretching and bond angles) via increasing the stiffness of the strong part of the potential to infinity. However, the naive way of doing this via holonomic constraints mistakenly ignores the energy contribution of the fast oscillations. The paper presents a mathematically rigorous discussion of the limit situation of infinite stiffness. It is demonstrated that the average of the limit solution indeed obeys a constrained Hamiltonian system but with a {\em corrected soft potential}. An explicit formula for the additive potential correction is given via a careful inspection of the limit energy of the fast oscillations. Unfortunately, the theory is valid only as long as the system does not run into certain resonances of the fast motions. Behind those resonances, there is no unique limit solution but a kind of choatic scenario for which the notion ``Takens chaos'' was coined. For demonstrating the relevance of this observation for MD, the theory is applied to a realistic, but still simple system: a single butan molecule. The appearance of ``Takens chaos'' in smoothed MD is illustrated and the consequences are discussed.}
    Keywords: ddc:000
    Language: English
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  • 97
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    An Adaptive Box Refinement in Subdivision Techniques for the Approximation of Dynamical Behavior (1996)
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    Publication Date: 2014-02-26
    Description: Recently subdivision techniques have been introduced in the numerical investigation of complicated temporal behavior of dynamical systems. In this article we intertwine the subdivision process with the computation of invariant measures and propose an adaptive scheme for the box refinement which is based on the combination of these methods. Using this new algorithm the numerical effort for the computation of box coverings is in general significantly reduced, and we illustrate this fact by several numerical examples.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
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  • 98
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    Solving Steiner Tree Problems in Graphs to Optimality (1996)
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    Publication Date: 2020-02-11
    Description: In this paper we present the implementation of a branch-and-cut algorithm for solving Steiner tree problems in graphs. Our algorithm is based on an integer programming formulation for directed graphs and comprises preprocessing, separation algorithms and primal heuristics. We are able to solve all problem instances discussed in literature to optimality, including one to our knowledge not yet solved problem. We also report on our computational experiences with some very large Steiner tree problems arising from the design of electronic circuits. All test problems are gathered in a newly introduced library called {\em SteinLib} that is accessible via World Wide Web.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
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  • 99
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    Survivable Mobile Phone Architectures: Models and Solution Methods (1996)
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    Publication Date: 2014-02-26
    Description: In the highly competitive area of telecommunications, cost, quality, and network management are among the most important aspects to be considered when designing a network. We study the problem of dimensioning a telecommunication network that is still operating in case of a failure of a network component. Given a demand between each pair of nodes of a telecommunication network and a finite set of possible capacities for each edge of the network, we consider the problem of deciding what capacity to install on each edge of the network in order to minimize the building cost of the network and to satisfy the demand between each pair of nodes, even if a network component fails. The routing of the demands must satisfy the following additional restrictions: (a) there is a maximum number of nodes allowed in each path between any pair of nodes (path length restriction), and (b) there is a maximum percentage of the demand between each pair of nodes that can be routed through any network component (diversification restriction). Moreover, the chosen capacities must be such that, for every single node or single edge failure, a certain percentage of the demand between any pair of nodes is reroutable (i.e. it ``survives'' the particular failure). We formulate the problem as a mixed integer linear programming problem and present a cutting plane algorithm as well as several heuristics for its solution. Furthermore, we discuss several ways to implement survivability into a telecommunication network.
    Keywords: ddc:000
    Language: English
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  • 100
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    On Critically Perfect Graphs (1996)
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    Publication Date: 2014-02-26
    Description: A perfect graph is critical if the deletion of any edge results in an imperfect graph. We give examples of such graphs and prove some basic properties. We investigate the relationship of critically perfect graphs to well-known classes of perfect graphs and study operations preserving critical perfectness.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
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