A calculus for generic, QoS-aware component composition

Software QoS properties, such as response time, availability, bandwidth requirement, memory usage, among many others, play a major role in the processes of selecting and composing software components. This paper extends a component calculus to deal, in an effective way, with them. The calculus models components as generalised Mealy machines, i.e., state-based entities interacting along their life time through well defined interfaces of observers and actions. QoS is introduced through an algebraic structure specifying the relevant QoS domain and how its values are composed under different disciplines. A major effect of introducing QoS-awareness is that a number of equivalences holding in the plain calculus become refinement laws. The paper also introduces a prototyper for the calculus developed as a ‘proof-of-concept’ implementation.FCT -Fuel Cell Technologies Program(FCOMP-01-0124-FEDER-020537

QoS-aware component composition

Component’s QoS constraints cannot be ignored when composing them to build reliable loosely-coupled, distributed systems. Therefore they should be explicitly taken into account in any formal model for component-based development. Such is the purpose of this paper: to extend a calculus of component composition to deal, in an effective way, with QoS constraints. Particular emphasis is put on how the laws that govern composition can be derived, in a calculational, pointfree style, in this new model

A Survey on Service Composition Middleware in Pervasive Environments

The development of pervasive computing has put the light on a challenging problem: how to dynamically compose services in heterogeneous and highly changing environments? We propose a survey that defines the service composition as a sequence of four steps: the translation, the generation, the evaluation, and finally the execution. With this powerful and simple model we describe the major service composition middleware. Then, a classification of these service composition middleware according to pervasive requirements - interoperability, discoverability, adaptability, context awareness, QoS management, security, spontaneous management, and autonomous management - is given. The classification highlights what has been done and what remains to do to develop the service composition in pervasive environments

Towards the introduction of QoS information in a component model

Assuring Quality of Service (QoS) properties is critical in the development of component-based distributed systems. This paper presents an approach to introduce QoS constraints into a coalgebraic model of software components. Such constraints are formally captured through the concept of a Q-algebra which, in its turn, can be smoothly integrated in the definition of component combinators.(undefined

A KPN based Model for Describing and Verifying the Interaction of Web Services

Correct interaction between Web services is essential for successful Web service composition. This paper proposes a Web Service Interaction Model (IWSN) that aims to ensure correct interaction between Web services, improve the scalability of Web service composition, solve behavioral compatibility issues in the process of Web service interaction, and promote the application of service composition technology in related fields. The Kahn Process Network (KPN) supports parallel computing based on data streams and channels, and the proposed Web Service Interaction Model in this article is based on the KPN. The formal semantics of the IWSN model are based on process algebra Pi calculus, and the model's properties are discussed. Finally, an application case is used to demonstrate how the IWSN model can be applied to Web service composition and interaction

A Conceptual Framework for Adapation

This paper presents a white-box conceptual framework for adaptation that promotes a neat separation of the adaptation logic from the application logic through a clear identification of control data and their role in the adaptation logic. The framework provides an original perspective from which we survey archetypal approaches to (self-)adaptation ranging from programming languages and paradigms, to computational models, to engineering solutions

A Conceptual Framework for Adapation

We present a white-box conceptual framework for adaptation. We called it CODA, for COntrol Data Adaptation, since it is based on the notion of control data. CODA promotes a neat separation between application and adaptation logic through a clear identification of the set of data that is relevant for the latter. The framework provides an original perspective from which we survey a representative set of approaches to adaptation ranging from programming languages and paradigms, to computational models and architectural solutions