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The miniaturization of hardware components has lead to the development of Wireless Sensor Networks (WSN) and networked-applications over them. Meanwhile, middleware systems have also been proposed in order to both facilitating the development of these applications and providing common application services. The development of middleware for sensor networks,(More)
Application servers have been widely adopted as distributed infrastructure (or middleware) for developing distributed systems. Current approaches for performance evaluation of application servers have mainly concentrated on the adoption of measurement techniques. This paper, however, focuses on the use of simulation techniques and presents an approach for(More)
A wireless sensor network (WSN) consists of a large number of small devices with computational power, wireless communication and sensing capability. These networks have been developed for a wide range of applications, such as habitat monitoring, object tracking , precision agriculture, building monitoring and military systems. Meanwhile, middleware systems(More)
Web services have played an important role in the development of distributed systems. In particular, the possibility of composing already implemented web services in order to provide a new functionality is an interesting approach for building distributed applications and business processes. The possibility of dynamically composing web services is also(More)
The concept of software architecture has created a new scenario for incorporating non-functional and transactional requirements into the software design. Transactional and non-functional requirements can be included in an architecture-based software development through formal approaches in which rst-order and temporal logic are utilised to deal with them.(More)
Group management service plays a key role in wireless sensor networks (WSNs) as it provides support to high level middleware services such as object tracking, security, fault-tolerance, power management, and so on. However, the way a group is managed may vary either from service to service or according to system conditions (e.g., power level, connectivity,(More)
The number of open specifications of middleware systems and middleware services is increasing. Despite their complexity, they are traditionally described through APIs (the operation signatures) and informal prose (the behaviour). This fact often leads to ambiguities and makes difficult a better understanding of what is really described. In this paper, we(More)