Patrick Albers

Web Services Composition

1. INTRODUCTION Nowadays many enterprises publish their applications functionalities on the Internet. This new generation of applications allows greater efficiency and availability for business. In fact, more and more applications make functionalities available using a web service format. However there are many services around the web, each one, taken alone, has a limited functionality. In many cases, a single service is not sufficient to respond to the users request and often services should be combined through services composition to achieve a specific goal. For example, if a user wants to travel, it is not sufficient to book a flight, but she should also take care of reserving a hotel, renting a car, getting entertained, and so on. Such composition is carried out manually today, it means that the user needs to execute all these services one by one and these tasks can be time and effort consuming. For that reason, the notion of composite services is starting to be used as a collection of services combined to achieve a users request. In other words, from a user perspective, this composition will continue to be considered as a simple service, even though it is composed of several web services. Nevertheless, prior to composing web services, candidate services should first be discovered and then selected. One difficulty is that many functionally

Improving Web Service Discovery by a Functional and Structural Approach

Service oriented Architecture (SOA) has been widely used in service computing applications and this fact has been encouraged the publication over the Web in a Web Service format. Whereas the number of Web services published on the Web is growing up, discovery techniques must be improved so as to retrieve more desirable services. Nowadays, the most commonly used technique is semantic filters based on ontological concepts. However, such mechanisms can leave out some important Web services of the matching process, because of their structural relationship not mentioned in an ontology. In order to overcome such problems, some authors have proposed a hybrid approach to combine traditional syntactic and semantic approaches. These proposals remain restricted especially with respect to complexity, precision and time of execution, thus making such solutions in most of cases unfeasible. In this paper, we combine semantic filters based on functional properties with a structural approach, analyzing each neighbor relationship in an ontology. The results showed a considerable improvement in terms of performance and a complexity reduction with respect to other existing techniques. Furthermore, we implement a tool called OWLS-S Discovery in order to simplify the use of our approach by developers.

A Framework for Automatic Composition of RFQ Web Services

The growth of Web service formats over the Internet is increasing. These services should often be composed to achieve a user request. We propose in this paper a framework to cope with web service composition, from discovery to optimization. This framework, called SPOC, is composed of four successive phases: discovery, planning, quote execution and optimization. Only RFQ (Request for Quote) web services are treated in this first version of SPOC. The Discovery phase aims to search for web services in a repository. The Planning phase determines which services satisfy the user request. The Quote Execution phase involves processing a Request For Quote (RFQ) by calling web services. The last phase optimizes these results giving tradeoff compositions. As a proof-of-concept example, we applied SPOC to public competition processes in Public Markets.

Un système de détection d'intrusions distribué pour réseaux ad hoc

In this paper we propose a distributed and modular architecture for an intrusion detection system (IDS) dedicated to mobile ad hoc networks (MANET). Our proposition relies on the use of local IDSs on each node of the MANET and on an agent based intra-IDS communication framework. It has been validated by a proof-of-concept prototype. which is presented in this paper. The article describes in detail, several network and application level attacks and how they can be detected. These attacks have been implemented und were used to validate our approach. Experiments exhibit fairly good results and the attacks are well and rapidly detected by our system. We conclude the paper by demonstrating that existing IDSs, such as SNORT, can be integrated as data sources for our architecture and by evaluating the benefits of mobile agents in the ad hoc context.

L'action concertée incitative Sécurité et informatique

L’organisation de la recherche en France fait intervenir divers acteurs et différents types de financement en fonction des types de recherche. Typiquement, les universités, les écoles, les EPST ont des politiques de recherche et de financement qui leur sont propres et qui sont négociées avec l’Etat lors de la mise en place des plans quadriennaux. C’est dans ce cadre que les équipes de recherche peuvent mettre en place des projets de recherche à moyen ou long terme et en obtenir le soutien, en particulier en moyens humains permanents.