Université de Picardie Jules Verne / Laboratoire des Technologies innovantes - INSSET Saint Quentin, France
ahmed.nait-sidi-moh@u-picardie.fr
Ahmed, Nait-Sidi-Moh received his Ph.D. degree in 2003 in Computer Engineering from the University of Technology of Belfort Montbéliard (UTBM), France. He is currently an Associate Professor of Computer Engineering at the University of Picardie Jules Verne (UPJV). Prior to joining the UPJV, he was research scientist and lecturer at the UTBM. His research interests include modeling, analysis and discrete event systems, performance evaluation and optimization,resources and information sharing, scheduling and interoperability for service composition, Geo-positioning and mobility.
Abstract: This book presents a general overview of the applications and use of geopositioning and GNSS for assisting the supervision and management of mobile terrestrial professions, information, traffic regulation, multimodal information, pedestrian mobility and indoor geopositioning, etc. It especially focuses on the field of mobility and terrestrial transport, the automotive industry and tourism (on foot, by bicycle or motorcycle, by car, by professional vehicles or by public transport, etc.). This book explores the many possibilities, developmental and organizational factors, as well as new paradigms, which will contribute to an essential part of GNSSâs civil economy, especially to Galileo in the mid-term and to Egnos in the short-term.
Several of GNSSâs integration structuring aspects in sustainable terrestrial mobilities will be analyzed; for example in terms of system architecture, data safety or legal constraints. Numerous diverse points of view will be presented regarding subjects such as dynamic cartography and new computing architectures of: mobility systems, interconnection, service quality, regulation or supervision functions of individual freedoms.
Abstract: Currently, each geographical area benefits from a set of wide range of local services, usually provided by several local entities, such as snow clearance, road works, public transportation, waste collection, fire fighting, emergency rescue authorities, etc. Despite each service fulfilling its own assigned task, they often suffer from a lack of communication and cooperation among them. Indeed, each service collects road-related information that may be useful to other services. Sharing information collected by each service would allow the acquisition of more knowledge about the driving context that may help drivers making appropriate decisions and, therefore, increase and improve road safety. Recently, wireless communication technologies associated with global navigation satellite systems and location-based information systems are among the powerful technologies used to develop interoperable intelligent transportation systems applications. Furthermore, the evolution of service-oriented infrastructures enables information sharing between applications over the network. In this paper, a distributed platform, called TransportML, for services interaction and cooperation is presented. It is an extended XML platform based on service-oriented architecture principles to recognize, monitor, and collect service information and description over a network. A prototype is developed and tested in urban and highway areas and results are reported to show the benefit of using this platform for sharing road information as well as servicesâ interactions.
Abstract: This paper deals with the specification, modelling and implementation of a pedagogic information system. In this context, a pervasive e-learning application is developed and its behaviour is described using a formal-based model. The application is mainly based on the cooperative navigation into pervasive environments, and using Web information spaces. The proposed modelling approach, in this paper, is based on Petri nets. This graphical tool has been used as a powerful graphical modelling language during the three last decades. The analysis techniques and mathematical background they propose allow graphical and analytical verification and validation of many relevant properties of systemsâ behaviour. Their powerful modelling allows a graphical description including various phenomena such as synchronization, parallelism, concurrency and resource sharing. The models and associated results, we develop in this paper, point out a very clear trade-off between expressive power, analysability and model consistency. After the modelling and analysis phase, the application is implemented and deployed on a specific platform. This implementation is started with a conceptual analysis study. Then, Java technologies, XML language and Oracle data base are used to design the application.
Abstract: Distributed systems become ubiquitous by allowing users access to a wide range of services at any time, anywhere, and from a variety of devices. In these open environments where there are many opportunities for both fraudulent services and misbehaving clients, service discovery systems are subject to security challenges. Controlling services' access is one of the fundamental issues that must be faced in the context of service discovery in distributed and open environments. Therefore, secure accesses and utilization of available services must be ensured for users. In our previous work, a contract-based approach for controlling the service access in a distributed computing context was presented. In this paper, we address the purpose and the usage of digital signature on negotiated electronic queries between a server and clients in service discovery systems and web service composition. The paper discusses the combined use of Timed Event Graphs and (max, +)- algebra to model, evaluate and optimize the performance of the signature process and client requests validation by a service provider (server). Based on an optimization resource allocation algorithm, an improvement study of the quality of service offered to the clients, in terms of waiting times and validation of their requests, is proposed. The results are reported and show the efficiency of the use of the proposed formal tools for performance analysis, evaluation and tuning of the considered process.
Abstract: This paper deals with the performance evaluation of a public transportation system in terms of waiting times at various connection points. The behaviour of a bus network is studied in the framework of Discrete Event Systems (DES). Two possible operating modes of buses can be observed at each connection stop: periodic and non-periodic mode. Two complementary tools, Petri nets and (max, +) algebra, are used to describe the network by a non-stationary linear state model. This one can be solved after solving the structural conflicts associated to the graphical representation. From the characteristic matrix of the mathematical model, we determine eigenvalues and eigenvectors that we use to evaluate the connection times of passengers. This work is finally illustrated with a numerical example.
Notes: Received 15 January 2007; accepted 27 August 2007. Available online 13 November 2007.
Abstract: Legal information certification and secured storage combined with documents electronic signature are of great interest when digital documents security and conservation are in concern. Therefore, these new and evolving technologies offer powerful abilities, such as identification, authentication and certification. The latter contribute to increase the global security of legal digital archives conservation and access. However, currently used cryptographic and hash coding concepts cannot intrinsically enclose cognitive information about both the signer and the signed content. Indeed, an evolution of these technologies may be necessary to achieve full text researches within hundreds or thousands of electronically signed documents. This article aims at describing a possible model along with associated processes to create and make use of these new electronic signatures called "meaningful electronic signatures" as opposed to traditional electronic signatures based on bit per bit computation.
Abstract: This paper aims to present P-Temporal Petri Net models for a specific kind of real industrial problems. This class of problems is known in the literature as CHSP, Cyclic Hoist Scheduling Problem. Several jobs have to flow through a production line according to an ordered bath sequence. Firstly, they enter the line from a loading buffer. Then, they will be soaked sequentially in a series of tanks containing specific chemical baths. Finally, they will leave the line at the unloading buffer. The processing time duration of each job in each tank is not constant but confined in a time interval. Moreover the transport of jobs between tanks is insured by a transport resource called hoist. In this paper, we propose a linear programming model to determine an optimal production plan of the studied system while determining the exact beginning and ending instants of each task. The second contribution of the paper is to propose P-Temporal Petri net models describing the behavior of many configurations of the production line. The proposed modeling approach enables to describe the system and validate its qualitative properties using the simulation tool Visual Object Net ++.
Abstract: In this paper, we present a modeling approach of a pervasive e-learning application based on high-level Petri Nets. This graphical tool has been used as a powerful graphical modeling language during the three last decades. Their mathematical analysis techniques allow an analytical verification of many relevant properties of systems' behavior. Their powerful modeling allows a graphical description including various phenomena such as synchronization, parallelism and concurrency. The proposed model and the associated results, in this paper, point out a very clear trade-off between expressive power, analyzability and model consistency. The second contribution of the paper consists in the implementation of the application. This implementation is started with a conceptual analysis study. Then, Java technologies, XML language and Oracle data base are used to design the application.
Abstract: The rapid expansion of wireless technologies and their interactions with wired networks together with wide spread of GNSS infrastructures allow today the development of location-based services (LBS). Furthermore, the evolution of service oriented infrastructures enables information sharing between applications over the network. In this paper, a distributed interactive platform, called TransportML, for LBS interaction and cooperation is presented. It is an extended XML platform based on Services Oriented Architecture (SOA) principles to recognize, to monitor, and to collect service information and description over the network. A prototype is developed, in the context of intelligent transportation systems (ITS), to allow sharing information collected by each service and then acquiring more information about the driving context. This information helps drivers making appropriate decisions and, therefore, increases and improves road safety. The prototype is tested in urban and highway areas and results are reported to show the benefit of using this platform for sharing road information as well as services interaction.
Abstract: Dioid algebra associated with Petri Nets are appropriate tools for modeling, analyzing, and
evaluating the performance of Discrete Event Systems (DESs). These tools are restricted to model systems
characterized by choice phenomena and conflicts. In this paper a routing policy to arbitrate and resolve the
conflicts encountered while modeling DESs by dioid algebra, is proposed. This routing policy is illustrated by con-
sidering services interaction as a case study. Results are reported to show the eectiveness of the proposed policy.
Abstract: As Web services composition arouses a growing interest,
most research works address implementation and execution
issues. Therefore, many composition languages
(BPEL, XLANG, WSFL, WSCI, to name a few of them) have
been proposed in the past few years. However, a weakness
of these languages is that they are difficult to use in
early stages of development, such as specification. In this
paper, an extension to UML 2.0 called âUML-S: UML for
Servicesâ is introduced. UML-S allows for a Model Driven
Engineering (MDE) of Web services and their interactions.
Abstract: This paper presents a new approach based on (max, plus) algebra to model cooperative navigation in pervasive e- learning applications. This modeling approach is appropriate for modeling these systems that are governed, on the one hand, by events occurrence in a discrete state space, and on the other hand, by synchronization and parallelism phenomena. In addition, this approach enables to verify in a formal way the model consistency.
Abstract: Ubiquitous and pervasive networks and applications include a growing number of research themes. In most use cases, applications require location information to interpret their environment and behave accordingly. In this paper, location algorithms and positioning methods that can be used for wireless geolocation are presented.
Abstract: In this paper, solving of conflicts of a Petri net model with techniques of (max, plus) algebra is considered. We define a routing policy which enables to solve and arbitrate the associated conflicts with a Petri net. We show how the conflict solving semantic prevents the deadlock in a graphical model while introducing routing functions into modelling. To illustrate the proposed results, a public transportation network is worked out. The aim is to analyze and evaluate the performance of a bus network which is represented by a Petri net with conflicts and a state model in (max, plus) algebra.
