Proving Finite Satisfiability of Deductive Databases

It is shown how certain refutation methods can be extended into semi-decision procedures that are complete for both unsatisfiability and finite satisfiability. The proposed extension is justified by a new characterization of finite satisfiability. This research was motivated by a database design problem: Deduction rules and integrity constraints in definite databases have to be finitely satisfiabl

A Behavioural Theory of Recursive Algorithms

"What is an algorithm?" is a fundamental question of computer science. Gurevich's behavioural theory of sequential algorithms (aka the sequential ASM thesis) gives a partial answer by defining (non-deterministic) sequential algorithms axiomatically, without referring to a particular machine model or programming language, and showing that they are captured by (non-deterministic) sequential Abstract State Machines (nd-seq ASMs). Moschovakis pointed out that recursive algorithms such as mergesort are not covered by this theory. In this article we propose an axiomatic definition of the notion of sequential recursive algorithm which extends Gurevich's axioms for sequential algorithms by a Recursion Postulate and allows us to prove that sequential recursive algorithms are captured by recursive Abstract State Machines, an extension of nd-seq ASMs by a CALL rule. Applying this recursive ASM thesis yields a characterization of sequential recursive algorithms as finitely composed concurrent algorithms all of whose concurrent runs are partial-order runs.Comment: 34 page

Quo Vadis Abstract State Machines? J.UCS Special Issue

In introducing this special ASM issue of J.UCS we point out the particular role this Journal played in the short history of the ASM method and add some reflections on its current status

Subject-Oriented Business Process Management

Activities performed in organizations are coordinated via communication between the people involved. The sentences used to communicate are naturally structured by subject, verb, and object. The subject describes the actor, the verb the action and the object what is affected by the action. Subject-oriented Business Process Management (S-BPM) as presented in this book is based on this simple structure which enables process-oriented thinking and process modeling. S-BPM puts the subject of a process at the center of attention and thus deals with business processes and their organizational environment from a new perspective, meeting organizational requirements in a much better way than traditional approaches. Subjects represent agents of an action in a process, which can be either technical or human (e.g. a thread in an IT system or a clerk). A process structures the actions of each subject and coordinates the required communication among the subjects. S-BPM provides a coherent procedural framework to model and analyze business processes: its focus is the cooperation of all stakeholders involved in the strategic, tactical, and operational issues, sharing their knowledge in a networked structure. The authors illustrate how each modeling activity through the whole development lifecycle can be supported through the use of appropriate software tools. The presentation style focuses on professionals in industry, and on students specializing in process management or organizational modeling. Each chapter begins with a summary of key findings and is full of examples, hints, and possible pitfalls. An interpreter model, a toolbox, and a glossary summarizing the main terms complete the book. The web site www.i2pm.net provides additional software tools and further material

Subject-Oriented Business Process Management

Information Systems Applications (incl.Internet); Business Information Systems; Computer Appl. in Administrative Data Processing; Management of Computing and Information System