Universität Ulm,
Fakultät für Informatik,
Abt. PM,
up: Mitarbeiterliste
Publikationen
- W. Gehring, P. Salamon, R.E.Whitney, P. Sibani
Correlation structure of landscapes of NP-complete optimization
problems at finite temperature
The decay of the autocorrelation function is studied for four
different combinatorial optimization problems in the high
temperature region. We find that the decay is in all cases
exponential, and we extract the temperature and system size
dependence of the correlation time. This dependence is always of
the Arrhenius form, and, with suitable scaling, is asymptotically
independent of system size.
Open Systems and Information Dynamics, Volume 11, Issue 2, June 2004, Pages 177-184,
ISSN 1230-1612.
- Wolfgang Gehring
Ein Rahmenwerk zur Einführung von Leistungspunktesystemen
Als Reaktion auf die Zunahme des Wettbewerbs in der Hochschulausbildung
empfehlen Hochschulrektorenkonferenz und Kultusministerkonferenz
die Einführung von Leistungspunktesystemen. Auch im
neuen Universitätsgesetz von Baden-Württemberg ist dies
ausdrücklich gewünscht.
Vielfach herrscht aber noch Unklarheit darüber, welche Maßnahmen
durchzuführen sind, um ein solches Leistungspunktesystem
einzuführen. Dieses Rahmenwerk soll Abhilfe schaffen.
Es ist ein Leitfaden zur Einführung von Leistungspunktesystemen;
es bietet Hilfestellungen und kann auch als Nachschlagewerk dienen.
Angestrebt ist ein Akkumulierungs- und Transfersystem,
welches sich an ECTS (dem European Credit Transfer System) orientiert.
Insgesamt soll ein Leistungspunktesystem einen erheblichen
Beitrag zur Qualitätssicherung in Studium und Lehre beitragen.
2. überarbeitete und erweitere Auflage, April 2002
ISBN 3-89559-078-9
- Wolfgang Gehring
A Mapping of XML Schema Types To C#
This paper proposes a mapping from XML Schema Definition
Language (XSD) to C#. XSDs are the type system of XML. In XSD,
many more types can be defined than in C# or a comparable
programming language. C#'s class library provides many classes
for creation and manipulation of XML objects; however, C# does
not support the XSD type system (like native C# types). We thus
propose a mapping which maps XSDs to C#. The mapping is injective
such that all semantically meaningful information in the schema is
maintained. C# properties are used to ensure restrictions on
types that have no native counterpart in C#.
- Wolfgang Gehring
On why C#'s type system needs an extension
Class libraries of
object-oriented programming languages like C# provide many
classes for creation and manipulation of XML objects; however,
they do not support the XSD type system like native types. In XSD,
many more types can be defined than in today's object-oriented
programming languages. In this paper, we look at a few examples of
why and where there are mismatches between the two worlds of XML
and OO in order to motivate why the type system of C# and related
OO-languages needs to be extended.
- P. Salamon, P. Sibani, W. Gehring, R.E.Whitney, R. Frost
Toward a taxonomy of NP-hard combinatorial optimization problems
It is argued that a taxonomy of hard combinatorial problems is needed to
better understand the performance of heuristic search algorithms based
on physical or biological analogies. We describe several methods of
gathering useful information for identifying classification schemes.
Statistical methods based on Monte Carlo sampling can yield the
thermodynamic portrait of the problem as well as the temperature
dependent autocorrelation function of the time series of energies.
Exhaustive enumeration methods based on exploring the neighborhood
of local minima can give the local density of states. Both the
autocorrelation function and the local density of states show
simple exponential behaviour for a large class of problems.
Bulletin of the American Physical Society, Volume 43, No.1, March 1998
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