Existing QoS-aware Web Services discovery architectures tend to focus solely on fulfilling the requirements of either the client or the provider. However, the interests of the provider and client are not equivalent. The provider’s goal is to maximize the profit and consume the least amount of resources. On the other hand, the client’s selection is determined by their own requirements which do not always reflect the real resource overheads. This research aims to provide a novel mobile Web Services discovery and selection method based on utility functions to balance the requirements for clients and providers. In the mobile environment, it is critical to conserve resource consumption in addition to fulfilling user requirements, as resources such as wireless network bandwidth and mobile device power are precious. The proposed service selection strategy enables service providers to balance the cost/performance ratios and utilize the network bandwidth more effectively, while the clients can still attain the functional and quality levels specified in the service request.

Existing QoS-aware Web Services discovery architectures tend to focus solely on fulfilling the requirements of either the client or the provider. However, the interests of the provider and client are not equivalent. The provider’s goal is to maximize the profit and consume the least amount of resources. On the other hand, the client’s selection is determined by their own requirements which do not always reflect the real resource overheads. This research aims to provide a novel mobile Web Services discovery and selection method based on utility functions to balance the requirements for clients and providers. In the mobile environment, it is critical to conserve resource consumption in addition to fulfilling user requirements, as resources such as wireless network bandwidth and mobile device power are precious. The proposed service selection strategy enables service providers to balance the cost/performance ratios and utilize the network bandwidth more effectively, while the clients can still attain the functional and quality levels specified in the service request.

To support wireless-oriented services, a new generation of Web services called Mobile services (M-services) has emerged. M-services provide mobile users access to services through wireless networks. One of the important issues in M-service environment is how to discover and access M-services efficiently. In this dissertation, we propose time and power efficient access methods for M-services. We focus on methods for accessing broadcast based M-services from multiple wireless channels. We first discuss efficient access methods in data-oriented wireless broadcast systems. We then discuss how to extend current wireless broadcast systems to support simple M-services. We present a novel infrastructure that provides a multi-channel broadcast framework for mobile users to effectively discover and access composite M-services. Multi-channel algorithms are proposed for efficiently accessing composite services. We define a few semantics that have impact on access efficiency in the proposed infrastructure. We discuss semantic access to composite services. Broadcast channel organizations suitable for discovering and accessing composite services are proposed. We also derive analytical models for these channel organizations. To provide practical study for the proposed infrastructure and access methods, a testbed is developed for simulating accessing M-services in a broadcast-based environment. Extensive experiments have been conducted to study the proposed access methods and broadcast channel organizations. The experimental results are presented and discussed. / Ph. D.

Au cours des dernières décennies, Internet a connu une révolution et une croissance exponentielle.A la suite de cette croissance, un grand nombre de services web et d’applications ont émergé pour répondre aux différents besoins des consommateurs. En même temps, l’industrie du réseau mobile est devenue omniprésente, ce qui rend la plupart des utilisateurs inséparables de leurs terminaux mobiles. La combinaison de la technologie mobile et des services web fournit un nouveau paradigme appelé services web mobiles. Ainsi, la consommation des services web a` partir des appareils mobiles émerge en proposant plusieurs facilites´ aux utilisateurs et en imposant plus de manipulations de ces services.En effet, afin que les utilisateurs trouvent des services répondant a` leurs besoins, un mécanisme de découverte est nécessaire, par ailleurs, les demandes sont devenues non seulement plus complexes mais aussi plus dynamiques, un service unique qui offre une fonctionnalité simple et primitive est devenu insuffisant pour satisfaire les besoins et les exigences complexes. Par conséquent, la combinaison de multiples services pour fournir un service composite est de plus en plus utilisée demandée. Nous parlons ainsi des mécanismes de découverte et de composition des services web mobiles. Ces deux paradigmes sont mutuellement liés et complémentaires.La découverte et la composition des services web dans un environnement mobile soulèvent plusieurs défis qui n’existent pas dans un environnement classique (non mobile). Parmi ces défis se trouve les contraintes limitées de l’appareil mobile, appelé dans ce travail contexte statique, ainsi que le changement de contexte qui est duˆ principalement a` la mobilité du dispositif, appelé contexte dynamique.Ainsi, l’objet de la présente thèse est de proposer un Framework de composition de services web mobile englobant deux approches complémentaires. Une première approche proposée est consacrée a` la découverte des services web mobiles appelée MobiDisc et une deuxième qui propose une solution a` la problématique de composition dans un contexte dynamique. Notre première approche exploite le contexte statique avec les propriétés de QoS et les préférences´ utilisateurs dans les descriptions sémantiques des services et de la requête utilisateur afin d’augmenter l’exactitude du processus de découverte. Quand a` l’approche de composition, elle met l’accent sur le contexte dynamique qui peut modifier le résultat de la composition. L’objectif est de déterminer la sensibilité des services au contexte dynamique et de générer des plans de composition pour l’utilisateur tries´ selon leurs valeurs de sensibilité globale lui permettant de choisir la meilleure composition. / Over the last two decades, Internet has grown exponentially. causing the emergence of web ser-vices and applications that meet the different needs of the consumers. During the same period, the mobile network industry has become ubiquitous, making most users inseparable from their mobile devices. So the combination of mobile technology and web services provides a new paradigm named mobile web services. Thus, the consumption of web services from mobile devices emerges by offering several facilities to users and requiring greater manipulation of these services such as discovery, composition and execution.Indeed, in order for users to find services that meet their requirements, a discovery mechanism is needed. Since requests have become not only more complex, but also more dynamic, a single service that offers simple and primitive functionality has become insufficient to satisfy the complex requirements. Therefore, the combination of multiple services to provide a composite service is more and more requested. We talk about mobile web service discovery and composition. These two paradigms are mutually linked and complementary.The discovery and composition of web services in a mobile environment raise several challenges that do not exist in a traditional (non-mobile) environment. Among these challenges are the limited constraints of the mobile device, called in this work static context, as well as the change of context which is due mainly to the mobility of the device which called dynamic context.In this thesis we propose a framework for the composition of mobile web services encompassing two complementary approaches. A first proposed approach called MobiDisc, speaking about the discovery of mobile web services and a second that proposes a solution to the problem of composition in a dynamic context. Our first approach uses the static context with QoS properties and user preferences in the semantic descriptions of services and the user query to increase the accuracy of the discovery process. As for the second compositional approach, it focuses on the dynamic context that can modify the composition result. The objective is to determine the sensitivity of the services to the dynamic context and to generate composition plans to the user ordered according to a sensitivity value.