Philippe Thiran

An Argumentation Framework for Communities of Web Services

As the number of Web services continues to increase, so does the opportunities to compose them to build more complex and complete business solutions. To facilitate and speed up Web-services discovery, Web services with similar (or equivalent) functionalities - such as flight booking and travel reservation - can be grouped into communities. Argumentation theory, implemented through a set of software agents that reason about Web services, can improve Web services performance through the notion of communities.

An Approach to Engineer Communities of Web Services: Concepts, architecture, operation, and deployment

This article presents an approach that provides the necessary assistance to those who are in charge of engineering communities of Web services. Current practices indicate that Web services providing the same functionality are gathered into one community, independently of their origins and the way they carry out this functionality. The provided assistance manifests itself with the concepts to use, the architecture to select, the operations to script, and the deployment to track. Two protocols frame the interactions in an environment of communities of Web services namely the Web Services Community Development Protocol and the Contract-Net Protocol. The former manages a community in terms of Web services attraction/registration/withdrawal to/with/from this community. The latter satisfies users’ needs in terms of Web services selection/contracting/triggering. Finally, the article presents a prototype illustrating the engineering approach with focus on Web services attraction.

Strategies for data reengineering

This paper describes and analyzes a series of strategies to migrate data-intensive applications from a legacy data management system to a modern DMS. Considering two ways to migrate the data and three ways to propagate the corresponding perturbation to the program code, the paper identifies six reference strategies that provide different levels of quality and induce different costs. Three of them are discussed in detail and illustrated by the conversion of COBOL files into a SQL database.

Reputation of Communities of Web Services - Preliminary Investigation

Web services communities can be seen as virtual clusters that agglomerate Web services with the same functionality (e.g., FlightBooking). However, selecting a community to deal with is a challenging task to users and providers. Reputation, besides other selection criteria, has been widely used for evaluating and ranking candidates. Interestingly, the definition of community reputation from the perspective of users differs from the perspective of Web service providers. In this paper, we introduce a reputation-based Web services community architecture and define some of the performance metrics that are needed to assess the reputation of a Web service community as perceived by users and providers.

Wrapper-based evolution of legacy information systems

System evolution most often implies the integration of legacy components, such as databases, with newly developed ones, leading to mixed architectures that suffer from severe heterogeneity problems. For instance, incorporating a new program in a legacy database application can create an integrity mismatch, since the database model and the program data view can be quite different (e.g. standard file model versus OO model). In addition, neither the legacy DBMS (too weak to address integrity issues correctly) nor the new program (that relies on data server responsibility) correctly cope with data integrity management. The component that can reconciliate these mismatched subsystems is the R/W wrapper, which allows any client program to read, but also to update the legacy data, while controlling the integrity constraints that are ignored by the legacy DBMS.This article describes a generic, technology-independent, R/W wrapper architecture, a methodology for specifying them in a disciplined way, and a CASE tool for generating most of the corresponding code.The key concept is that of implicit construct, which is a structure or a constraint that has not been declared in the database, but which is controlled by the legacy application code. The implicit constructs are elicited through reverse engineering techniques, and then translated into validation code in the wrapper. For instance, a wrapper can be generated for a collection of COBOL files in order to allow external programs to access them through a relational, object-oriented or XML interface, while offering referential integrity control. The methodology is based on a transformational approach that provides a formal way to build the wrapper schema and to specify inter-schema mappings.

An Approach to Incentive-Based Reputation for Communities of Web Services

Community of web services (CWS) is a society composed by a number of functionally identical web services. The communities always aim to increase their reputation level in order to obtain more requests. In this paper, we propose an effective mechanism dealing with reputation assessment for communities of web services. The proposed mechanism is based on after-service feedbacks provided by the users to a run-time logging system. The proposed method defines the evaluation metrics involved in reputation assessment of a community, and supervises the logging system in order to verify the validity and soundness of the feedbacks provided by the users. In this paper, the proposed framework is described, a theoretical analysis of its assessment and its implementation along with empirical result discussions are provided. We also show how our model is efficient, particularly in very dynamic environments.

Agent-based communities of web services: an argumentation-driven approach

The objective of this paper is to discuss how to sustain the growth of Web services through the use of communities. A community aims at gathering Web services with the same functionality independently of their origins, locations, and functioning. To make Web services more responsive to the environment in which they run and to be more flexible when managing communities, Web services are associated with software agents enhanced with argumentation capacities. This type of agents persuade and negotiate with other peers for the sake of letting their respective Web services reach their goals in an efficient way. Associating Web services with this type of agents allows them to select good communities and allow the communities to host the good Web services and to select the best ones for composite scenarios. Furthermore, this provides satisfactory solutions for three open problems: starvation (Web services refuse all the possibilities of joining communities), competition-free (Web services accept joining any community without being selective), and unfairness (always the same Web services members of a community are selected out of many others to participate in composite scenarios). In addition, the paper presents a formal and computational persuasive and negotiation protocol to manage the attraction and retainment of Web services in the communities and their identification for composite services.

Wrapper development for legacy data reuse

This paper is devoted to the technology of wrappers for legacy data systems reuse. Their characteristics are outlined and a generic wrapper architecture is defined. This architecture is intended to be instantiated for specific legacy data models and systems. A general methodology is proposed to define the architecture components. The methodology is supported by an operational CASE tool that helps developers to generate wrappers.

Contextual ontologies: motivations, challenges, and solutions

Contextual ontologies are ontologies that characterize a concept by a set of properties that vary according to context. Contextual ontologies are now crucial for users who intend to exchange information in a domain. Existing ontology languages are not capable of defining such type of ontologies. The objective of this paper is to formally define a contextual ontology language to support the development of contextual ontologies. In this paper, we use description logics as an ontology language and then we extend it by introducing a new contextual constructor.

Towards a community-based, social network-driven framework for Web services management

This paper discusses a framework to manage Web services using the concept of community and the metaphor of social networking. On the one hand, a community gathers Web services that offer similar functionalities together. These Web services are referred to as either master or slave. On the other hand, social networking captures all interactions that occur between Web services located in the same or separate communities. Five interactions are identified and referred to as supervision, substitution, competition, collaboration, and recommendation. The mining exercise over the social networks that capture these interactions results in assigning social qualities to Web services, similar to those found in peoples daily life such as selfishness, fairness, and trustworthiness. Experiments showing the mining exercise are also reported in this paper.