Bernhard Thomas

• Dr
• Lecturer at University of Cologne

Zusammenfassung Vor rund 25 Jahren endete das SUPRENUM-Projekt. Ziel dieses großen, vom Forschungsministerium geförderten deutschen Projekts war die Entwicklung eines parallelen SUPerREchners, insbesondere für große NUMerische Anwendungen. In einer gemeinsamen Initiative von Forschungszentren, der Industrie und universitären Expertengruppen sollte...

It is widely agreed that standards provide numerous benefits when available and enforced. Company-internal Information Systems (IS) management procedures and solutions, in the following coined IS ‘standards’, allow for harmonizing operations between company units, locations and even different service providers. However, many companies lack an organ...

Despite the growing attention being given to cloud computing by researchers and practitioners, the deployment of cloud computing is still in its infancy. For this to change, client companies need to know which of their IT services are appropriate for cloud computing. They often lack a sufficiently specific, yet applicable method to determine their...

Whereas recently cloud computing has gained enormous interest in research and practice, the deployment of cloud computing in larger companies and multi-nationals is still in its infancy. Practice often lacks a sufficiently specific, yet applicable method to determine a company’s cloud readiness and to identify and assess IT services to be taken to...

This paper gives a very general and rough survey of the hardware, the system software, and the applications software of the SUPRENUM system. Most supercom puter applications today are based on grid data struc tures. Grid applications also play an essential role in the SUPRENUM development. We therefore place some emphasis on this grid orientation i...

To examine the subatomic components of matter, atomic physicists require giant particle accelerators - and where even their capabilities are not sufficient, or if only to understand the experimental results they furnish, it is necessary to use supercomputers. This paper discusses various aspects of supercomputers such as vector processing, multipro...

Parallelrechner (im engeren Sinne) kennzeichnen die 3. Generation von Superrechnern nach Vektorrechnern (1. Generation) Multi-Vektorrechnern mit mehreren CPUs und dem Konzept eines gemeinsamen Speichers (2. Generation).

Calculates the differences in payoffs between diel vertical migrating and nonmigrating zooplankton. Results depend on the abundance and growth rate of the algae, the filtration rate and density of the zooplankton, the strategy-dependent efficiency of converting food into reproduction, temperature-dependent egg developmental time, day length, and pr...

Unter dem Systemaspekt weisen viele Phänomene, die den unterschiedlichen naturwissenschaftlichen Fächern zugerechnet werden, Gemeinsamkeiten auf. In der Sprache der Mathematik formuliert und gegebenenfalls durch Simulationprogramme unterstützt, bieten solche Gemeinsamkeiten die Möglichkeit zu fächerübergreifendem Verständnis. Systembeschreibungen d...

Evolutionary stable sets are used as an extension of the concept of an evolutionarily stable strategy (ESS). They have, as sets, essentially the same properties as ordinary ESSs. Here, ES sets are applied to the characterization of what will happen in an asexual population of mixed-strategists under frequency-dependent selection. Such a population...

Evolutionarily Stable Strategies (ESS) in phenotypic models are used to explain the evolution of animal interactive behaviour. As the behavioural features under consideration are assumed to be genetically determined, the question arises how underlying a genetical system might affect the results of phenotypic ESS-models. This question can be fully t...

The problem of evolutionarily stable strategies (ESS) in sexual populations can be investigated by means of genetical ESS-models which link common sense, phenotypic ESS-models to an underlying genetical system. Thorough results are obtained for multi-strategy models in diploid, panmictic populations on the basis of multi-allelic, one-locus systems....

As an extension of the concept of an evolutionarily stable strategy (ESS) evolutionarily stable sets are introduced, i.e. sets of equilibrium strategies (EQS) which have much of the properties of an ESS. They are primarily used with evolutionary game models that allow a continuum of EQSs, none of which can be an ESS, but also include common ESSs as...

Different aspects and modifications of the definition of an evolutionarily stable (ES) strategy that have been considered in the literature can be incorporated in a unifying concept which regards the population context. This concept of evolutionary stability will generally characterize population states in both pure- and mixed-strategist models. In...

Mit diesem Beitrag soll anhand des Konzepts der Evolutionär Stabilen Strategie (ESS) gezeigt werden, wie die Modellierung eines biologischen Langzeitprozesses, hier die Evolution von Verhalten, vereinfacht werden kann durch einen Ansatz, der Modellbildung und theoretische Konzepte miteinander verknüpft.

The concept of an evolutionarily stable strategy (ESS) in its original definition is inappropriate for application to models where the pay-offs to the strategies depend on the distribution of their frequencies in a non-linear manner. Therefore, an extention of the original “global” concept is given by the definition of a “local ESS”, which brings i...

ESS-models are considered in the frame of adequate dynamical systems. This leads to a method of global representation of the dynamical characteristics, which allows for a comprehensive view on the relations among ESS-matrices. As an extension of ESS-models, the concept of ESS-models with changing matrix is introduced, which, in applications, makes...

On the basis of some principles from the philosophy of science, the inadequacy of the ESS-theory as introduced by Maynard Smith and Price as a biological theory is discussed, and an improved ESS-theory for finite populations is presented which can adopt the ideas of the original formalism, although modified. Resulting are explicit conditions on the...

The concept of a population with subpopulations that are isolated with respect to strategies is introduced and applied to a biologically important class of cases, showing that no proper mixed evolutionarily stable strategies can exist in such cases.

The experimental work of Fulton and Dingle on the amebo-flagellate transformation is reexamined from a system-theoretical point of view. A quite general system and a set of terms have been developed describing a wide range of different transformation processes. This system has been applied to generate artificial abstract organisms which show the tr...

Bei einer Vielzahl von Modellen der Biowi senschaften verlangt eine mathematische Beschreibung in Form von Differentialgleichungen die Berücksichtigung von Zeitverzögerungen (Retardierungen), so etwa bei zeitverzögerten Anfangswertproblemen: $$ \begin{array}{*{20}{c}} {Y(t) = F(t,Y(t),Y{{(t - {\alpha _i})}_{i = 1, \cdots,s}}),t\varepsilon \left[ {a...

Zur Beschreibung von Zellsystemen mit festen oder variablen Reifungszeiten werden gewöhnliche Differentialgleichungen sowie Differentialgleichungen mit festen oder veränderlichen Zeitverzögerungen eingesetzt. Zunächst wird geprüft, was bei Änderung der Zuflußrate und der Reifungszeit am isolierten Reifungscompartment geschieht. Dann wird ein einfac...