Henda Ben Ghezala

A Requirement-Centric Approach to Web Service Modeling, Discovery, and Selection

Service-Oriented Computing (SOC) has gained considerable popularity for implementing Service-Based Applications (SBAs) in a flexible and effective manner. The basic idea of SOC is to understand users’ requirements for SBAs first, and then discover and select relevant services (i.e., that fit closely functional requirements) and offer a high Quality of Service (QoS). Understanding users’ requirements is already achieved by existing requirement engineering approaches (e.g., TROPOS, KAOS, and MAP) which model SBAs in a requirement-driven manner. However, discovering and selecting relevant and high QoS services are still challenging tasks that require time and effort due to the increasing number of available Web services. In this paper, we propose a requirement-centric approach which allows: (i) modeling users’ requirements for SBAs with the MAP formalism and specifying required services using an Intentional Service Model (ISM); (ii) discovering services by querying the Web service search engine Service-Finder and using keywords extracted from the specifications provided by the ISM; and(iii) selecting automatically relevant and high QoS services by applying Formal Concept Analysis (FCA). We validate our approach by performing experiments on an e-books application. The experimental results show that our approach allows the selection of relevant and high QoS services with a high accuracy (the average precision is 89.41%) and efficiency (the average recall is 95.43%).

Load-balancing and energy aware routing protocol for real-time flows in mobile ad-hoc networks

Choosing the shortest path for real-time flows is insufficient. Respecting the deadline cannot be insured nor guaranteed neither with exhausted energy resource nor with overloaded intermediate mobile nodes. The main problem is to choose the reliable, efficient and correct routing protocol to route real-time flows with respect to their deadlines within MANET constraints. This paper introduces the Energy Delay aware based on Dynamic Source Routing, ED-DSR. ED-DSR efficiently utilizes the network resources such as the intermediate node energy and load in order to balance traffic load. It ensures both timeliness and energy efficiency by avoiding low-power and busy intermediate node. Simulation results, using NS simulator, improve that the protocol increases the volume of delivered packets in-time (around 50% for the data flows with strict deadline and around 63% with non-strict deadline), prolongs the network lifetime (up to 66%) and shortens the end-to-end delay.

Model-Driven Development of Context-aware Adaptive Learning Systems

This paper presents the results of our innovative approach for the realization of a model driven development framework for modeling context-aware adaptive learning activities within Context-aware and adaptive learning environments. Its core element consists of a domain specific visual modeling language called CAAML (Context-aware Adaptive Activities Modeling Language). After, we present the developed authoring tool based on CAAML language and that aims to support pedagogical designers to model context-aware adaptive learning activities and transform them into executable models represented in IMS-LD.

Exploration techniques of the spatial data warehouses: overview and application to incendiary domain

Data warehouses have appeared in answer to the new requirements of database technologies. With them appeared some automated techniques like knowledge discovery in databases (KDD), data mining (DM) and online analytical processing (OLAP), which have registered a great demand in relational, transactional and finally in geographical databases. We give a survey of the state of the art of this research field. We mention the principles of data warehouses defining the context of geographical information, and present models used to build the data warehouse. Then, the tools permitting exploration of data warehouses and considered as tools for decision making are introduced. An evaluation of the technique of generalization is carried out using incendiary data. On the other hand, we expose a suggestion to manage incendiary data by cubic representation.

An energy efficiency and delay guarantee service selection protocol in MANET

The real-time applications deployed in MANETs are affected by the mobile nodes power constraints and the real-time database service providers system stability. In this paper, we aim to handle the time-constrained requests within their deadline despite of the mobile nodes limited energy. We propose a cross layer service selection protocol which ensures both timelines and energy efficiency. The proposed solution discards low-power route, overhead route and overloaded service provider. We evaluate the performance of our proposed protocol using the NS2. Simulation results show that the protocol decreases the deadline packets miss ratio and reduces the energy consumption.

Towards an Intelligent Decision Making Support

This paper presents an intelligent framework that combines case-based reasoning (CBR), fuzzy logic and particle swarm optimization (PSO) to build an intelligent decision support model. CBR is a useful technique to support decision making (DM) by learning from past experiences. It solves a new problem by retrieving, reusing, and adapting past solutions to old problems that are closely similar to the current problem. In this paper, we combine fuzzy logic with case-based reasoning to identify useful cases that can support the DM. At the beginning, a fuzzy CBR based on both problems and actors’ similarities is advanced to measure usefulness of past cases. Then, we rely on a meta-heuristic optimization technique i.e. Particle Swarm Optimization to adjust optimally the parameters of the inputs and outputs fuzzy membership functions.

QoS testing of service-based applications

Web services (WSs) are becoming increasingly popular because of their potential in several application domains including e-Enterprise, e-Business, e-Government, and e-Science. Based on open XML standards, WS technology allows the construction of massively distributed and loosely coupled applications. A service composition mechanism should satisfy not only functional properties but also non-functional quality of service (QoS) ones. In this paper, we introduce a discrete-events modeling approach for service-based applications (SBAs). This approach is oriented towards QoS evaluation through simulation.

Meta-Modeling Based Secure Software Development Processes

This work suggests a multilevel support to software developers, who often lack knowledge and skills on how to proceed to develop secure software. In fact, developing software with such quality is a hard and complex task that involves many additional security-dedicated activities which are usually omitted in traditional software development lifecycles or integrated but not efficiently and appropriately deployed in some others. To federate all these software security-assurance activities in a structured way and provide the required guidelines for choosing and using them in a flexible development process, authors used meta-modeling techniques and dynamic process execution that consider developers affinities and products states. The proposed approach formalizes existing secure software development processes, allows integration of new ones, prevents ad-hoc executions and is supported by a tool to facilitate its deployment. A case study is given here to exemplify the proposed approach application and to illustrate some of its advantages.

Approaches to analyze cyber terrorist communities

Cyber terrorism has become a major threat to world peace and global economic prosperity. The exponential growth of cyber terrorist communities has given rise to the need for the development of effective approaches, techniques, and tools to gain in-depth understanding of the ecosystem of these communities (specifically, in terms of inner structure, working strategies, and operation tactics). In the literature, numerous research works on the detection and analysis of cyber terrorist communities have been conducted. More notably, Social Networks Analysis (SNA) has emerged to be a key research field that attempts to analyze such cyber terrorist communities. In this paper, we survey, study, and classify the main approaches related to the analysis of cyber terrorist communities. We also discuss their characteristics, strengths and limitations. The approaches have been categorized into two main categories, namely, SNA based approaches and hybrid approaches. Furthermore, we identify areas that entail further research works with the aim of devising and developing more effective approaches that aid in analyzing cyber terrorist communities.

An Energy and Delay-Aware Routing Protocol for Mobile Ad-Hoc Networks

A mobile ad-hoc network (MANET) is an autonomous system of mobile nodes which are free to move randomly thus forming a temporary network. Typical applications of MANET are in disaster recovery operations which have to respect time constraint needs. However, it is very difficult to guarantee any quality of service to a real-time flow in such network because it must take into account the specificities of these networks. This paper introduces the Energy Delay aware based on Dynamic Source Routing, ED-DSR. ED-DSR efficiently utilizes the network resources such as the node energy and the node load in order to balance traffic load. It ensures both timeliness and energy efficiency by avoiding low-power node and busy node. Simulation results, using NS-2 simulator, show that the protocol prolongs the network lifetime (up to 66%), increases the volume of packets delivered while meeting the data flows real-time constraints and shortens the end-to-end delay.