Abdeslam En-Nouaary

An Abstract Framework for Introducing Computational Trust Models in JADE-Based Multi-Agent Systems

Agents in open distributed systems rely on their peers to achieve their goals. In such situation, the trust management become a critical subject that must be handled. Formalizing trust as a computer concept will help agents improving the decision making process and decrease the risk of being unsatisfied. This research aims to develop a practical framework that introduce computational trust models in multi-agent systems applications. The framework presented in this paper is based on an abstract structure that handle different trust models, and provide a ready to use development tool for JADE applications.

Towards a Framework for the Analysis and Evaluation of Computational Trust Models in Multi-agent Systems

In open dynamic multi-agent systems, trust is commonly considered as a critical concept to be handled and managed. Computational trust models are a kinds of formal models that have been proposed to manage trust in such situation. These models present a new form of distributed intelligence in virtual societies and collective intelligence. However, the diversity of those models makes user confused about which one to choose. Different testbeds have been established to evaluate trust and reputation models and verify their robustness and efficiency. However, a lack of flexibility to handle scenarios related to multi-context trust models arise with those testbeds. We present in this paper a framework for evaluating computational trust models that provides to users more flexibility while comparing trust models in open systems and shows analysis results in chart diagrams. The ultimate objective is to evaluate and classify available computational trust models.

Analysis of common business rules in BPMN process models using business rule language

Process models describe graphically, events, activities, control flow and dataflow logic that constitute a business process. Nevertheless most graphical modeling notations required by organization stakeholders such as BPMN, are not provided with a formal semantics, limiting the possibility of analysis to informal approaches such as observation techniques. While most of the existing formal approaches for BPMN models verification focus on the control-flow, very few has treated the Business rules verification angle. In this paper, we present a new approach that uses the Business Rule Language (BRL) which helps us express several common types of business rules that could be verified by a DFS algorithm adapted for the BPMN standard. The proposed approach has been implemented as an Eclipse plugin called, “BPMN Process Analysis”.

A Constraint-based Approach for Checking Vertical Inconsistencies between Class and Sequence UML Diagrams

The modern software development processes enable evolving software systems and refining models across software life cycle. However, these evolution attitudes may lead to some consistency problems among models at different levels of abstraction. Hence, it is required to discover and detect the potential inconsistencies occurring in models when developing a system. This paper focuses on checking the vertical consistency of UML models using an approach based on defining constraints at the meta-level. These constraints are expressed using EVL (Epsilon Validation Language) to ensure the consistency of models. Representative examples of constraints for checking vertical inconsistencies between class and sequence diagrams are proposed to illustrate our contribution.

On Formal Modeling and Validation of Signaling Protocols for Web Real-Time Communications using SDL

Abstract WebRTC (Web Real-Time Communication) is a Web real-time audio and video communication technology, which is natively supported by the browser and is not dependent on third-party plug-ins. In order to establish a WebRTC session, there is a need for a signaling protocol to help different parties to agree on parameters such as codecs, types of media, transport addresses, etc. The paper presents a formal model and validation for a complete signaling exchange between two WebRTC communicating browsers. The formal model is built using SDL (Specification and Description Language) to describe the structure, the data, and the behaviour of the system, while the validation of the resulting model is done using the reachability analysis technique. The ultimate objective of the validation is to show that the system model is free of design errors so that it can be analyzed first and then used to generate code automatically for WebRTC solutions.

DataFlow Analysis in BPMN Models.

Business Process Management and Notation (BPMN) is the defacto standard used in enterprises for modeling business processes.However, this standard was not provided with a formal semantics, which makes the possibility of analysis limited to informal approaches such as observation. While most of the existing formal approaches for BPMN models verification focus on the control-flow, only few has treated the data-flow angle. The latter is important since the correct execution of activities in BPMN models is based on data’s availability and correctness. In this paper, we present a new approach that uses the DataRecord concept, adapted for the BPMN standard. The main advantage of our approach is that it locates the stage where the data flow anomaly has taken place as well as the source of data flow problem. Therefore the designer can easily correct the data flow anomaly.The model’s data flow problems are detected using an algorithm specific for the BPMN standard.

Toward a Practical Method for Introducing and Evaluating Trust Learning Models in Open Multi-agent Systems

In multi-agent systems, agents often interact with each others to achieves their own goals. In open dynamic systems, trust between agents become a critical challenge to make such interactions effective. Many trust models have been proposed to formalise this concept. These models are such good for dealing with trust by proposing components that present a computational form of this concept and a learning strategies to manage it. Components and learning strategies differs from one model to another. This diversity may influence the decision of a user about the best trust model to use in his system. A comparative study is needed to evaluate each trust model and to show the prediction quality of each one. Several testbeds for the evaluation of trust models have been proposed. However, those testbeds are not flexible enough to handle different scenarios in various contexts. In this paper we formulate a practical method based on a framework that introduce the trust concept into open distributed systems, and a testbed that can be used to evaluate trust models in different contexts.

Managing Inconsistencies in UML Models: A Systematic Literature Review

Software systems are often modeled as a set of related UML diagrams. Due to the overlapping multi-view nature of UML and due to the incremental and iterative nature of the used software development process, these diagrams might contain inconsistencies. Thus, it is of utmost importance to detect, analyze and fix these inconsistencies before implementing the system. In this paper, we elaborate a transverse view of the aforementioned activities. More explicitly, this work proposes a Systematic Literature Review (SLR) that evaluates the existing techniques for managing inconsistencies using different research questions. The ultimate objective of this review is to come up with new recommendations that should be taken into consideration when conceiving a new proposal for checking inconsistencies.

Detecting and fixing UML model inconsistencies using constraints

Complex software systems are often modeled as a collection of related UML diagrams, each of which describes particular aspects of the system being investigated. These diagrams might contain inconsistencies due to the evolving nature of software systems and to the refinement of the models across the software life cycle. It is so mandatory to discover the potential inconsistencies in UML models as soon as possible before implementing the system. This paper proposes a method for checking the consistency of UML models, based on formal constraints defined at the meta-model of UML. These constraints are described using EVL (Epsilon Validation Language) by matching related diagrams features at the meta-level. EVL also helps repair and correct the inconsistencies being detected. Our method is easily automated and is complete in terms of coverage of both potential inconsistencies and the UML diagrams commonly used.

A Formal Model for WebRTC Signaling Using SDL

We present a formal approach to modeling Jingle protocol and the related IETF protocols STUN, TURN and ICE using Specification and Description Language (SDL). The aim is to perform a complete unambiguous model for signaling exchange between two WebRTC communicating entities, and study their behavior in real network conditions like the presence of NAT (Network Address Translation) and firewalls. The main objective is to demonstrate the feasibility of using a formal language, such as SDL to model a system as complex as IETF RTCWeb architecture using Jingle as a signaling mechanism.