Apostolos V. Zarras

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Service-oriented computing is now acknowledged as a central paradigm for Internet computing, supported by tremendous research and technology development over the last ten years. However, the evolution of the Internet, and in particular, the latest Future Internet vision, challenges the paradigm. Indeed, service-oriented computing has to face the ultra large(More)
The problem we deal with in this paper is the dynamic substitution of stateful services that become unavailable during the execution of service orchestrations. Previous research efforts focusing on the reconfiguration of conventional distributed systems enable the substitution of system entities with other prefabricated passive entities that serve as a(More)
Providing software qualities such as availability, adaptability and maintenability to long-running distributed applications , forms a major challenge for the configuration management of a software system. Modifications of sys-tem's structure are expected to happen on-the-fly, to cause minimum execution disruption, and to be effected in a way that preserves(More)
Future middleware platforms will need to be more configurable in order to meet the demands of a wide variety of application domains. Furthermore, we believe that such platforms will also need to be re-configurable, for example to enable systems to adapt to changes in the underlying systems infrastructure. A number of technologies are emerging to support(More)
Transactions are contracts that guarantee a consistent, transparent, individual system state transition and their use is widespread in many different kinds of computing systems. Some well known standards (e.g. CORBA) include the specification of services that provide transactional properties. In this paper, we present a formal method for the systematic(More)
This paper focuses on the development of a principled methodology for the dependability analysis of composite Web services. The first step of the methodology involves a UML representation for the architecture specification of composite Web services. The proposed representation is built upon BPEL and introduces necessary extensions to support the second step(More)
In this paper we present CoWSAMI, a middleware infrastructure that enables context awareness in open ambient intelligence environments, consisting of mobile users and context sources that become dynamically available as the users move from one location to another. A central requirement in such dynamic scenarios is to be able to integrate new context sources(More)
Middleware is a software layer standing between the operating system and the application, enabling the transparent integration of distributed objects. In this paper, we propose a framework that facilitates the comparison of middleware infrastructures. Our approach serves for identifying similarities and differences between middleware infrastructures and(More)
This paper discusses a base UML profile for architecture description as supported by existing Architecture Description Languages (ADLs). The profile may be extended so as to enable architecture modeling both as expressed in conventional ADLs and according to existing runtime infrastructures (e.g., system based on middleware architectures). 1 INTRODUCTION(More)