At a time when the web is switching from a data-oriented view to a service-oriented view, we can envision an environment where services are dynamically and automatically combined to solve new problems that one single service cannot solve. Agent technology provides a good basis for creating such an environment but many issues remain to be solved. This paper presents a step towards a dynamic serv...

An algebraic approach to the view consistency problem in software development is provided. A view is formalised as a sentence of a viewpoint language; a viewpoint is given by a language and its semantics. Views in possibly different viewpoints are compared over a common view for consistency by a heterogenous pull-back construction. This general notion of view consistency is illustrated by sever...

In this paper we propose a model of an object–oriented database with views. A view in our approach can have arbitrary complex structure. The crucial point of our model is that a view schema is totally separated from the original database schema. By this separation we achieved two following goals: logical data independence provided by a view schema and strong mechanism for data hiding and securi...

One major approach to realise database integration is to adapt and merge the database schemas by defining views. When integrating object-oriented databases, the views need to adequately support object identity and methods. View objects need to be identified on the basis of the objects they have been derived from. Methods must be callable from the query processor without impeding query optimisat...

A variety of view definitions have been defined for object oriented database systems. In this paper we study the problem of what happens to a view when the underlying schema and database are updated. We introduce the new concept of non-side effect view. A non-side effect view is a view which is re-computed dynamically so that schema modifications are (whenever possible) "filtered out" from appl...

This paper primarily addresses the issue of what we really mean by ‘ObjectOriented Databases’. It is argued that the conventional view of an object-oriented database (OODB) − with the main object-oriented features consisting of object identity, classification, specialisation, composition and encapsulation − is rather basic and has limited applications. In order to more adequately support both n...

We discuss the software development issues involved in designing parallel programs using object oriented techniques. Simulations involving 1D and 2D Particle In Cell plasma codes illustrate how C++ programs can eeectively describe complex simulations while performing with reasonable eeciency when compared to the equivalent Fortran programs. The scalable object oriented modeling techniques close...

This paper investigates the problem of integration between relational and object-oriented databases. We discuss an approach based on class and attribute mappings and show how OQL, the ODMG query language, can be embedded in a set of primitives of a mapping language to serve as a basis for object-relational data integration. We then describe the technique used in the implementation of a prototyp...

Views are an established technique for virtually restructuring data, classes, and schemata so as to meet the needs of speciic applications or users; for integrating heterogeneous and distributed systems (for example, data warehouse systems); and for achieving interoperability by hiding the idiosyncrasies of component systems to be integrated into one uniied, yet fed-erated system. Because the r...

In this article, an approach to modelling of componentbased systems and formal description of their behaviour is proposed. It is based on a novel component model defined by a metamodel in a logical view and by description in the π-calculus in a process view. The model addresses dynamic aspects of software architectures including component mobility. Furthermore, a method of behavioural modelling...