Using Autarky to Evaluate Quantified Boolean Formulae

In this paper, we discuss algorithmical implications for the extension of autarky from SAT to evaluate QBF formulas. First, we describe the Davis-Putnam procedure for SAT. Then we explain efficient known data structures as used for our SAT solver and known extensions to QBF. Finally, we introduce the concept of autarky in general and 2-autarkies in particular and discuss algorithmical implications for QBF. To the best of our knowledge we are the first to discuss described techniques for pruning the search tree of QBF solvers

Vorlesung zur "Einführung in die Programmierung mit Java"

Vorlesung und Übung zur "Einführung in die Programmierung mit Java" (3 SWS), Institut für Informatik, Universität zu Köln, Wintersemester 2008/09. Pflichtveranstaltung im Grundstudium in den Studiengängen Mathematik, Wirtschaftsmathematik und Wirtschaftsinformati

Towards a Framework for the Classification of Usability Issues

Part 9: Industry Case StudiesInternational audienceThis case study proposes a novel framework, which aims to support UX designers and practitioners in the classification of identified usability issues. Existing inspection methods often lack in providing further information and steps about the effort to fix those issues. Therefore, the developed framework provides four categories for classifying usability issues in order to generate a score, which represents the present level of UX maturity. Furthermore, the score enables the comparison of UX maturity levels between systems with similar customer journeys, based on the identified usability issues. Results support system designers in their decision-making process of replacing, maintaining or modernizing the system in question. First results reveal that the proposed framework could be used as a meaningful extension of existing usability methods within different application domains, for instance the heuristic evaluation

The fully automatic installation of a Linux cluster

We present a non interactive system, called FAI (Fully Automatic Installation), to install a Debian Linux operating system on a PC cluster. We take one or more virgin PCs, turn on the power and after a few minutes Linux is installed, configured and running on the whole cluster, without any interaction necessary. In addition, the configuration can be changed automatically on all Linux cluster nodes. Thus we have a scalable method for installing and updating a cluster with little effort involved. We use the Debian distribution and a collection of shell- and Perl-scripts for the installation process. Changes to the configuration files of the operating system are made by the tool cfengine

Scientific Data and Knowledge Management in Aerospace Engineering

In aerospace engineering, simulation is a key technology. Examples are pre-design studies, optimization, systems simulation, or mission simulations of aircrafts and space vehicles. These kinds of complex simulations need two distinct technologies. First, highly sophisticated simulation codes for each involved discipline (for example, codes for computational fluid dynamics, structural analysis, or flight mechanics) to simulate the various physical effects. Secondly, a simulation infrastructure and well-designed supporting tools to work effectively with all simulation codes. This paper focuses on the infrastructure and the supporting tools, especially for managing both the data resulting from large-scale simulation and the necessary knowledge for conducting complex simulation tasks. Examples of recent developments at the German Aerospace Center in the fields of data and knowledge management to support aerospace research by e-Science technologies are presented

The fully automatic installation of a Linux cluster

We present a non interactive system, called FAI (Fully Automatic Installation), to install a Debian Linux operating system on a PC cluster. We take one or more virgin PCs, turn on the power and after a few minutes Linux is installed, configured and running on the whole cluster, without any interaction necessary. In addition, the configuration can be changed automatically on all Linux cluster nodes. Thus we have a scalable method for installing and updating a cluster with little effort involved. We use the Debian distribution and a collection of shell- and Perl-scripts for the installation process. Changes to the configuration files of the operating system are made by the tool cfengine

RepoGuard: A Framework for Integration of Development Tools with SourceCode Repositories

Today modern software development is not possible without the aid of tools like version control systems, bug tracking systems or instruments that ensure the compliance with code conventions. Unfortunately, all of these tools “live in their own world”, are only loosely coupled and do not interact with each other. RepoGuard addresses this problem by linking version control systems to other software development tools. It is implemented as an extension to several version control systems and provides interfaces to integrate other tools. The use of RepoGuard allows maximum control and validation of all committed resources before they are permanently stored. Additionally, RepoGuard provides communication channels in order to inform all relevant stakeholders about the failure or success of the process. Overall, RepoGuard provides simple but effective means to guarantee software quality standards in distributed development processes

des John von Neumann-Instituts für Computing

Computing (NIC) und hiermit des ZAM als wesentlicher Säule des NIC. Um den akademischen Nachwuch