7619422
The Symbolic Integration of Exact PDEs
An algorithm is described which decides if a given polynomial differential expression ? of multivariate functions is exact, i.e. whether there exists a first integral P such thatDxP=? for any one x of a set of n variables and to provide the integral P. A generalization is given to allow integration in the case that the exactness is prevented by terms which contain only functions of less than n independent variables.
3233905
Programs for applying symmetries
In this paper the programs APPLYSYM, QUASILINPDE and DETRAFO are described which aim at the utilization of infinitesimal symmetries of differential equations. The purpose of QUASILINPDE is the general solution of quasilinear PDEs. This procedure isusedby APPLYSYM fortheapplication of point symmetries for either Q calculating simila,rity variables toperform a point transformation which lowers the order of an ODEoreffectiveiy reduces the number of explicitly occuringindependent variablesin aPDE(-system) or for . generalizing given special solutions of ODEs/PDEs with new constant parameters. The program DETRAFO performs arbitrary pointand contact transformations of ODEs/PDEs and is applied if similarity and symmetry variables have been found. The program APPLYSYM is used in connection with the program LIEPDE for formulating and solving the conditions for pointand cent act symmetries which is described in [4]. The actual problem solving is done in all these programs through a call to the package CRACK for solving overdetermined PDE systems.
46113649
Analytical Decoupling, Decision of Compatibility and Partial Integration of Systems of Non-Linear Ordinary and Partial Differential Equations
895386
Size Reduction and Partial Decoupling of Systems of Equations
A method is presented that reduces the number of terms of systems of linear equations (algebraic, ordinary and partial differential equations). As a byproduct these systems have a tendency to become partially decoupled and are more likely to be factorizable or integrable. A variation of this method is applicable to nonlinear systems. Modifications to improve efficiency are given and examples are shown. This procedure can be used in connection with the computation of the radical of a differential ideal (differential Grobner basis).
1703030
Optimizing GoTools' Search Heuristics using Genetic Algorithms
GoTools is a program which solves life & death problems in the game of Go. This paper describes experiments using a Genetic Algorithm to optimize heuristic weights used by GoTools' tree-search. The complete set of heuristic weights is composed of different subgroups, each of which can be optimized with a suitable fitness function. As a useful side product, an MPI interface for FreePascal was implemented to allow the use of a parallelized fitness function running on a Beowulf cluster. The aim of this exercise is to optimize the current version of GoTools, and to make tools available in preparation of an extension of GoTools for solving open boundary life & death problems, which will introduce more heuristic parameters to be fine tuned.
5578706
Checking Life-and Death Problems in Go
1084067
On exceptions as first-class objects in Ada 95
This short position paper argues that it might be beneficial to try to bring the exception model of Ada 95 more in-line with the object-oriented model of programming. In particular, it is felt that exceptions --- being such an important concept for the development of fault-tolerant software --- have deserved a promotion to first-class objects of the language. It is proposed to resolve the somewhat awkward dichotomy of exceptions and exception occurrences as it exists now in Ada 95 by treating exceptions as (tagged) types, and exception occurrences as their instances.
196094
Integrating object-oriented programming and protected objects in Ada 95
Integrating concurrent and object-oriented programming has been an active research topic since the late 1980's. There is a now a plethora of methods for achieving this integration. The majority of approaches have taken a sequential object-oriented language and made it concurrent. A few approaches have taken a concurrent language and made it object-oriented. The most important of this latter class is the Ada 95 language, which is an extension to the object-based concurrent programming language Ada 83. Arguably, Ada 95 does not fully integrate its models of concurrency and object-oriented programming. For example, neither tasks nor protected objects are extensible. This article discusses ways in which protected objects can be made more extensible.
41947706
Secure Communication in Distributed Ada
This document describes an implementation of secure communication for distributed applications in Ada 95. It explains the basics of cryptography and introduces the problem of key exchange. After a brief description of distributed systems in Ada 95, the modular structure of the implementation and the way it handles key distribution is presented.
15117189
Global Biclustering of Microarray Data
We consider the problem of simultaneously clustering genes and conditions of a gene expression data matrix. A bicluster is defined as a subset of genes that show similar behavior within a subset of conditions. Finding biclusters can be useful for revealing groups of genes involved in the same molecular process as well as groups of conditions where this process takes place. Previous work either deals with local, bicluster-based criteria or assumes a very specific structure of the data matrix (e.g. checkerboard or block-diagonal) (Ryan et al., 2005). In contrast, our goal is to find a set of flexibly arranged biclusters which is optimal in regard to a global objective function. As this is a NP-hard combinatorial problem, we describe several techniques to obtain approximate solutions. We benchmarked our approach successfully on the Alizadeh B-cell lymphoma data set (Alizadeh et al., 2000)
40351745
Vom Rechenzentrum zum Zentrum für Informations- und Kommunikationstechnik
Belege fur die technische Unterstutzung der menschlichen Informationsverarbeitung finden sich bis weit in die Vergangenheit. Die historischen Entwicklungslinien der drei Teilfunktionen der Informations- und Kommunikationstechnologie (IuK-Technik) — Transport, Verarbeitung und Speicherung — sind lange Zeit getrennt verlaufen. Hiermit ist gemeint, das die technischen Losungen fur die der drei Teilfunktionen unabhangig waren.