Over the past few years, XML has become a standard for data representation and data exchange over the web. Although XML data is self-describing, most application domains tend to use document schemas, given as Document Type Definitions (DTDs) or XML-Schemas. An XML document is considered valid if it conforms to the constraints and rules specified in its schema. A lot of work has been done in querying XML documents. Recently, the issue of updating XML documents has gained attention because an update operation may invalidate the whole document. In this paper, we present existing approaches to update XML documents and offer a new one that guarantees that the updated document still conforms to its DTD. Our methodology updates XML documents without breaking their validity by storing and retrieving XML documents in/from an object database.

The Web has become closely ingrained with our life and work and massive effort for Web development and maintenance continue to take place in an ad hoc manner, resulting in poor quality Web systems and applications. As a consequence, web engineering and more precisely web requirements engineering is becoming of major importance in web development process. In this paper, we will tackle the validation phase of web requirements engineering; whereby we present a new navigational requirements' validation approach that verifies the completeness, correctness, and consistency of the web navigations. In specific, we propose a web-based navigational requirements validation through visualization and animation.

C++ applications suffer from the lack of a garbage collector which has been acknowledged as one of their major defects. Therefore, these applications need an automatic memory management lifecycle because their memory management techniques are developed explicitly and manually. For instance, research effort has been done to improve object memory management technique, such as reference counter, incremental garbage collector, conservative garbage collector, smart pointer, and so on. These techniques have some limitations, such as amalgamated functional and technical aspects in the same object-oriented programs and its implementation has to be realized manually. Generally speaking, we propose a mechanism and develop a prototype to i) separate object lifecycle management from functional aspects and ii) implement and integrate this task automatically and implicitly. To eliminate implicitly storage management defects, our prototype is based on mark and sweep algorithm and separation of concerns approaches such as aspect-oriented programming.

We propose a model for building object oriented applications based on the composition of application slices or fragments that provide their own overlapping definitions or expectations of the same domain objects. Different slices may implement different functional or implementation concerns, or embody different access rights and privileges to the same domain objects. We call such slices views and we recognize that the behavior embodied in views may be abstracted into generic class-like algebraic structures called viewpoints, from which views for specific domain classes may be generated. We are interested in the problem of distributing view based applications when different sites access different slices of the same domain objects. Specifically, we are interested in the problem of offering different views of the same domain objects to different client programs in a CORBA-like environment. We first discuss the principles behind view programming, and then explore ways in which objects with views may be distributed in a way that support's different sets of functionalities to different client programs. An interesting application of view programming in a distributed context is the selective duplication of object slices.

The use of formal description techniques allows the partial automation of the design, the validation, and the implementation of communication protocols and distributed algorithms. In this paper, we present a methodology for validation of distributed algorithms and protocols, and our experiences of using the Estelle language, and a simulation and validation tool, called Veda, to simulate and validate complex distributed algorithms for the distributed implementation of multi-rendezvous. Some design errors in published distributed rendezvous algorithms were found. We obtain from these experiences heuristic guidelines for trouble shooting of distributed algorithms.

A model and a formal specification of the personal communication service obtained by the application of an object-oriented system design methodology is presented and described using the executable object-oriented specification language Mondel. The goal of developing a specification of PCS is primarily to introduce some structure and formalism in its description, which has so far been done informally, and also to provide a better understanding of its constituent elements and their interrelationships. As Mondel is an executable specification language, simulation is used to verify the basic functionality defined in this specification of PCs. Simulation using various scenarios also provides a means of presenting the different concepts of PCS.>