The role of the service concept in model-driven applications development

This paper identifies two paradigms that have influenced the design of distributed applications: the middleware-centred and the protocol-centred paradigm, and proposes a combined use of these two paradigms. This combined use incorporates major benefits from both paradigms: the ability to reuse middleware infrastructures and the ability to treat distributed coordination aspects as a separate object of design through the use of the service concept. A careful consideration of the service concept, and its recursive application, allows us to define an appropriate and precise notion of platform-independence that suits the needs of model-driven middleware application development

Semantic verification of Behavior Conformance

This paper introduces a formal yet practical method to verify whether the behavior design of a distributed application conforms to the behavior design of the enterprise in which the application is embedded. The method allows both enterprise architects and application architects to talk about designs in their own terms, and introduces a common set of terms as the linking pin between enterprise and application designs. The formal semantics of these common terms allows us to verify the conformance between an enterprise and its applications formally and automatically

Robot control based on qualitative representation of human trajectories

A major challenge for future social robots is the high-level interpretation of human motion, and the consequent generation of appropriate robot actions. This paper describes some fundamental steps towards the real-time implementation of a system that allows a mobile robot to transform quantitative information about human trajectories (i.e. coordinates and speed) into qualitative concepts, and from these to generate appropriate control commands. The problem is formulated using a simple version of qualitative trajectory calculus, then solved using an inference engine based on fuzzy temporal logic and situation graph trees. Preliminary results are discussed and future directions of the current research are drawn

A distributed directory service for Greenstone

Greenstone is a software for creating and maintaining distributed digital library collections. It provides a sophisticated federation mechanism for the collections. In order to support alerting notification about changes in the distributed collections, we propose a distributed directory service for the management of the distributed Greenstone installations. The Greenstone directory service (GDS) acts on top of the distributed Greenstone structure for the management of collections. This paper describes both, the initial distributed Greenstone structure and the distributed directory service

Modular and composable extensions to smalltalk using composition filters

Current and future trends in computer science require extensions to Smalltalk. Rather than arguing for particular language mechanisms to deal with specific requirements, in this position paper we want to make a case for two requirements that Smalltalk extensions should fulfill. The first is that the extensions must be integrated with Smalltalk without violating its basic object model. The second requirement is that extensions should allow for defining objects that are still adaptable, extensible and reusable, and in particular do not cause inheritance anomalies. We propose the composition filters model as a framework for language extensions that fulfills these criteria. Its applicability to solving various modeling problems is briefly illustrated