Noura Faci

LinkedWS: A Novel Web Services Discovery Model Based on the Metaphor of Social Networks

Abstract Web services are increasingly becoming the de facto implementation for the service-oriented architecture paradigm for enterprises due to their ease of use. Nevertheless, discovering these Web services is still hindered by many challenges that are partially attributed to shortcomings found in the discovery registry models (e.g., UDDI) used nowadays. These registries do not, for example, capture the rich information resulting from the various types of interactions between Web services. To address these shortcomings, and inspired by the conventional human social networks on the net, like Facebook and Twitter, we develop LinkedWS , a social networks discovery model to capture the different interactions that occur between Web services. Based on these interactions, specialized relationships are spawned and discerned. Examples of these relationships are collaboration and substitution. This paper describes LinkedWS and its potential, and reports on its implementation status.

Towards reliable multi-agent systems: An adaptive replication mechanism

Distributed cooperative applications are now increasingly being designed as a set of autonomous entities, named agents, which interact and coordinate (thus named a multi-agent system). Such applications are often very dynamic: new agents can join or leave, they can change roles, strategies, etc. This high dynamicity creates new challenges to the traditional approaches of fault-tolerance. In this paper, we will focus on crash failures, with usual preventive approaches by replication. But, as criticality of agents may evolve during the course of computation and problem solving, static design is not appropriate. Thus we need to dynamically and automatically identify the most critical agents and to adapt their replication strategies (e.g., active or passive, number of replicas), in order to maximize their reliability and their availability. In this paper, we describe a prototype architecture, supporting adaptive replication. We also discuss and compare various control strategies for replication, one using agent roles, and another using inter-agent dependences as types of information to infer and estimate criticality of agents. Experiments and measurements are also reported.

Towards a Method for Engineering Social Web Services

This paper motivates the blend of social computing with service-oriented computing, giving “birth” to social Web services. On the one hand, social computing builds user applications upon the principles of collective action and content sharing. On the other hand, service-oriented computing builds enterprise applications upon the principles of service offer and demand and loose coupling. Thanks to this blend social Web services can operate taking into account with whom they worked in the past and with whom they would like to work in the future. To engineer social Web services, this paper presents a four-step method that addresses several questions related to the engineering exercise. These questions are what relationships exist between Web services, what social networks correspond to these relationships, how to build social networks of Web services, and what social behaviors can Web services exhibit. Experiences dealing with implementing social Web services are, also, reported in the paper.

Towards a Monitoring Framework for Agent-Based Contract Systems

The behaviours of autonomous agents may deviate from those deemed to be for the good of the societal systems of which they are a part. Norms have therefore been proposed as a means to regulate agent behaviours in open and dynamic systems, and may be encoded in electronic contracts in order to specify the obliged, permitted and prohibited behaviours of agents that are signatories to such contracts. Enactment and management of electronic contracts thus enables the use of regulatory mechanisms to ensure that agent behaviours comply with the encoded norms. To facilitate such mechanisms requires monitoring in order to detect and explain violation of norms. In this paper we propose a framework for monitoring that is to be implemented and integrated into a suite of contract enactment and management tools. The framework adopts a non-intrusive approach to monitoring, whereby the states of a contract with respect to its contained norms can be inferred on the basis of messages exchanged. Specifically, the framework deploys agents that observe messages sent between contract signatories, where these messages correspond to agent behaviours and therefore indicate whether norms are, or are in danger of, being violated.

Towards a framework for weaving social networks principles into web services discovery

Despite the regular updates of the existing discovery techniques, the discovery of Web services continues to exacerbate users due to the large number of available Web services on the Internet. Different needs trigger the discovery of Web services such as developing new, value-added composite services and sustaining the high availability of other peers. These needs reveal three types of relationships between Web services, which are substitution, competition, and collaboration. The proposed framework includes tools that capture and update these relationships into social networks so that Web services discovery can be made smooth. Some implementation and simulation details are, also, discussed in this paper.

Applying electronic contracting to the aerospace aftercare domain

The contract project was a European Commission project whose aim was to develop frameworks, components and tools to model, build, verify and monitor distributed electronic business systems based on electronic contracts. In this context, an electronic contract provides a specification of the expected behaviours of individual services, with the assumption that these services are often enacted by autonomous agents. Using the theoretical tools created by the project, in this paper we describe the complete life cycle of instantiating an electronic contracting system using the contract framework within the aerospace aftercare domain. Thus, we use a natural language description of parts of the types of contracts used in this domain to generate individual norms amenable to a computational representation, and how these norms are used to generate a concrete contract monitor. Moreover, we describe a concrete implementation of contract agents in the AgentSpeak(L) language and how these agents interact within a concrete instantiation of contract.

Experience and prospects for various control strategies for self-replicating multi-agent systems

Distributed cooperative applications (e.g.,e-commerce) are now increasingly being designed as a set of autonomous entities, named agents, which interact and coordinate(thus named a multi-agent system). Such applications are often very dynamic: new agents can join or leave, they can change roles, strategies, etc. This high dynamicity creates new challenges to the traditional approaches of fault-tolerance. As relative importance of agents may evolve during the course of computation and problem solving,we need to dynamically and automatically identify the most critical agents and to adapt their replication strategies (e.g., active or passive, number of replicas), in order to maximize their reliability and their availability. One important issue is then: what kind of information could be used to estimate which agents are most critical agents? In this paper, we will first introduce our prototype architecture for adaptive replication. Then, we will discuss various kinds of information and strategies to estimate criticality of agents: static dependences, dynamic dependences, roles, norms, and plans. Some preliminary measurements and future directions will also be presented.

Specifying and implementing social Web services operation using commitments

This paper discusses the specification and development of social Web services using commitments. Social Web services establish and maintain networks of contacts, count on their (privileged) contacts when needed, form with other peers strong and long lasting collaborative groups, and know with whom to partner so that ontology reconciliation is minimized. To guarantee the proper execution of these operations, social Web services need to comply with the regulations of the social networks in which they have signed up. This compliance is verified using commitments. Two types of commitments are identified: social and business. The former connect Web services to social networks. And the latter connect social Web services to composite social Web services. A proof-of-concept system to detect commitment violations is, also, discussed in this paper.

Network-based social coordination of business processes

Abstract This paper presents a social coordination approach that addresses the issue of conflicts over resources during business process execution. A business process consists of tasks that persons and/or machines execute. The resources, that business processes require at run-time, are sometimes limited and/or not-renewable. The approach uses a set of social relations that connect tasks/persons/machines together. These relations are the basis of developing specialized networks that capture the interactions during business process execution and are used to recommend corrective actions when conflicts over resources occur. These actions are dependent on the properties of tasks, persons and machines properties which referred to as transactional, activity, and operational, respectively. A system that demonstrates the approach is also discussed.

Measuring the Radicalisation Risk in Social Networks

Social networks (SNs) have become a powerful tool for the jihadism as they serve as recruitment assets, live forums, psychological warfare, as well as sharing platforms. SNs enable vulnerable individuals to reach radicalized people, hence triggering their own radicalization process. There are many vulnerability factors linked to socio-economic and demographic conditions that make jihadist militants suitable targets for their radicalization. We focus on these vulnerability factors, studying, understanding, and identifying them on the Internet. Here, we present a set of radicalization indicators and a model to assess them using a data set of tweets published by several Islamic State of Iraq and Sham sympathizers. Results show that there is a strong correlation between the values assigned by the model to the indicators.