Smart proxies are objects often used to adapt and customize distributed object-oriented systems in a non-invasive way. For example, smart proxies are common used to provide support to quality of service attributes. In this paper, we investigate the use of smart proxies in order to provide replication transparency in middleware systems that support the implementation of Web services. The system presented in the paper, called SmartWS, supports the prime replicated server selection policies proposed in the literature. The paper also provides guidelines that help Web service users to choose the policy more suitable to a given application. A new server selection policy that combines several advantages of the already proposed policies is also described. The paper also presents results obtained from experiments performed with a prototype implementation of SmartWS. Such results reinforce the policy selection guidelines presented in the paper.

Computer vision systems are based on capture and processing of images, from which information for the application is extracted. This paper presents a hybrid platform which can be easily configured and efficiently used for a large number of applications in computer vision. It consists of a dedicated processor integrated to the capture element, connected to a general-purpose computer for the highlevel application processing. The camera module consists of a DSP executing a middleware which provides all the basic functions, such as image capture, low-level image processing, control, and communication. Experiments showed that good performance is obtained with this platform, and the framework presented may simplify the development of computer vision systems. An application for the hardware-software architecture presented here would be the validation and prototyping of computer vision systems.