Almost Linear B\"uchi Automata

We introduce a new fragment of Linear temporal logic (LTL) called LIO and a new class of Buechi automata (BA) called Almost linear Buechi automata (ALBA). We provide effective translations between LIO and ALBA showing that the two formalisms are expressively equivalent. While standard translations of LTL into BA use some intermediate formalisms, the presented translation of LIO into ALBA is direct. As we expect applications of ALBA in model checking, we compare the expressiveness of ALBA with other classes of Buechi automata studied in this context and we indicate possible applications

Zweckbindung in ämterübergreifenden Verwaltungsworkflows: Zugriffsschutz durch feingranulare Verschlüsselung auf XML-Basis

E-Government bietet das Potential, Verwaltungsprozesse durch ämterübergreifende Vorgangsbearbeitung zu optimieren. Dabei muss die datenschutzrechtliche Zweckbindung jedoch technisch abgesichert werden. Durch ein XML-basiertes Verschlüsselungsverfahren kann dies erreicht werden

Choreographing security and performance analysis. DEGAS project paper. Submitted for publication

Abstract. We describe a UML-based method which supports model-driven development of service-oriented architectures including those used in Web services. Analysable content is extracted from the UML models in the form of process calculus descriptions. These are analysed to provide strong guarantees of satisfactory security and performance. The results are reflected back in the form of a modified version of the UML model which highlights points of the design which can give rise to operational difficulties. A design platform supporting the methodology, Choreographer, interoperates with state-of-the-art UML modelling tools such as Poseidon. We illustrate the approach on an example.