Hakim Mabed

Institut FEMTO-ST | FEMTO ST · Département Informatique des Systèmes Complexes (DISC)

Energy efficiency is a major concern and a critical issue for energy constrained wireless networks. In this context, clustering is commonly used for topology management and maximizing the network lifetime. Clustering approaches typically use a multi-hopping mechanism where Cluster Heads (CHs) near the Base Station (BS) consume higher energy since t...

Global pandemics such as Covid-19 have led to massive loss of human lives and strict lockdown measures worldwide. To return to a certain level of normalcy, community awareness on avoiding high population density areas is significantly important for infection prevention and control. With the availability of new telecommunication technologies, it is...

With Terahertz band (0.1–10 THz) technology, several nanoscale ad hoc applications could be developed, such as intrabody health monitoring, programmable material, etc. The fundamental element to ensure the functionality of these applications is the way to access the radio communication channel. The main challenge with nanocommunication is the need...

Under a dense and large IoT network, a star topology where each device is directly connected to the Internet gateway may cause serious waste of energy and congestion issues. Grouping network devices into clusters provides a suitable architecture to reduce the energy consumption and allows an effective management of communication channels. Although...

Wireless mobile networks are widely used during large catastrophes such as earthquakes and floods where robust networking systems are indispensable to protect human lives. The objective of this paper is to present a self-adaptive emergency call protocol that allows keeping potential victims connected to the core network through the available functi...

The arrival of modern 5G networks is expected to witness a massive increase in internet connections and base stations. Energy optimization is one of the imminent worldwide issues for green computing. Most of the energy efficiency existing works only focus on short-term vision of energy consumption and fails to contemplate the rechargeable battery d...

Smart surface is a new conveying technology composed of a 2D planar surface presenting a matrix of distributed autonomous blocks. Every block contains a micro-electro-mechanical system (MEMS) actuator that controls the transfer of a possible object located above the block to the neighboring blocks, using air-jet forces. The spatial characteristics...

The recent progress in nanotechnologies is giving birth to a novel topology of wireless networks characterized by a high local density and an intensive node instability such as in WBAN and swarm micro-robots systems. In this paper, we show that classical and dedicated ad hoc nanonetwork routing solutions are inefficient in this case and present a l...

Energy efficiency is a major concern in the emerging mobile cellular wireless networks since massive connectivity is to be expected with high energy requirements from the network operators. Non-orthogonal multiple access (NOMA) being the frontier multiple access scheme for 5G, there exists numerous research attempts on enhancing the energy efficien...

New applications in the field of radio networks require a high concentration of micro-machines (micro-robots, sensors/actuators) in a small space. Those devices are characterized by a high volatility and limited computing, storage and energy capabilities. Traditional routing approaches in ad hoc networks are unusable due to a significant amount of...

The nano terahertz networks represent one of the promising areas in the field of wireless telecommunications. Technological advances in miniaturization of antennas and terahertz communications have paved the way for new network applications such as the body network, the programmable material and multi-core processors. Some of these applications req...

The race for the miniaturization of electromechanical equipments has seen tremendous progress in recent years. In this context, nano-wireless networks composed of a large number of tiny equipments concentrated in a reduced area find multiple applications in the field of multi-core processors, programmable matter or nano-sensors networks. In order t...

In this paper, we study the optimal use of a conveying surface, called smart surface, using distributed microrobotic system that is designed to manipulate fragile micro objects. The smart surface is composed of a 2D array of decentralized micro-modules. Each micro-module is composed of a microactuator, a microsensor, computing and communication uni...

The programmable material is one of the most challenging problems in micro-robot networking. In addition to the problems that arise by the miniaturization of millimeter-scale mobile devices, the conception of the distributed asynchronous algorithms allowing the coordination of large number of robots remains a very complex task. Micro-robot network...

Programmable matter i.e. matter that can change its physical properties, more likely its shape according to an internal or an external action is a good example of a cybermatics component. As it links a cyberized shape to real matter, it is a straight example of cyber-physical conjugation. But, this interaction between virtual and real worlds needs...

Multimedia Broadcast Multicast Service system supports efficient diffusion of multicast multimedia services in cellular networks. Our previous work shows that the radio resource management problem for MBMS can be modeled as a combinatorial optimization problem which tries to find optimal assignment of power and channel codes [1]. In this paper, we...

Multimedia Broadcast Multicast Service (MBMS) system supports efficient diffusion of multicast multimedia services in cellular networks. Our previous work shows that the radio resource management (RRM) problem for MBMS can be modeled as an optimization problem which tries to find optimum assignment solution of power and channel codes in a given sea...

MEMS microrobots are miniaturized electro-mechanical elements, made using the techniques of micro-fabrication. They have limited energy capacity and low memory space. Self-reconfiguration is required for MEMS microrobots to complete their mission and/or to optimize their communication. In this paper, we present a self-reconfiguration protocol from...

Novel platforms of modular robot systems have been developed with important applications in safety, transportation and sensing domains. In such systems, modular robots are able to change their organization in order to obtain different shapes. The conception of distributed programs allowing the 'optimal' reorganization of a set of robots into a spec...

Self-reconfiguration for mobile microrobots currently needs a positioning system and a map of the target shape. Traditional positioning solutions, such as GPS or multilateration are not applicable in the micro-world, and maps sharing does not scale. In the literature, if we want a self-reconfiguration of microrobots to a target shape that consists...

The programmable material is one of the most challenging problem in micro-robotic field. In addition to the problems raised by manufacturing of millimeter-scale mobile devices; the conception of the distributed asynchronous algorithms allowing the coordination of large number of robots remains a very complex task. Programmable materials have many a...

In this paper, we propose an improvement of the logical topology by using self-reconfiguration protocol in MEMS microrobot networks. Recently, solutions have been given for this problem for a chain of microrobots as a starting physical topology; the advantage of these solutions is that they are distributed protocols without map of the target shape...

In this paper we propose a distributed and robust parallel redeployment algorithm for MEMS micro robots. MEMS micro robots are low-power and low-memory capacity devices that can sense and act. To deal with the MEMS micro robots characteristics, in this paper, we present an efficient redeployment algorithm without predefined positions of the target...

In this paper we propose a distributed and efficient parallel self-reconfiguration algorithm for MEMS microrobots. MEMS microrobots perform various missions and tasks in a wide range of applications including odor localization, firefighting, medical service, surveillance and security, and search and rescue. To achieve these tasks the self-reconfigu...

In this paper we present a dynamic self reconfiguration protocol for MEMS micro robots. The protocol presented in this paper is without map of the target shape which makes it efficient and scalable. In other words, nodes do not store the positions that build the target shape. Consequently, memory usage for each node is reduced to a constant complex...

To design a cellular radio network (GSM, UMTS, WiFi …) it is indispensable today to use a radio planning software. In current commercialized tools, radio network planning is based on a numerical evaluation of a set of radio metrics, directly linked to quality of service notion, such as interference, throughput, coverage, capacity … The network conf...

MEMS micro robots are low-power and low memory capacity devices that can sense and act. One of the most challenges in MEMS micro robot applications is the self-reconfiguration, especially when the efficiency and the scalability of the algorithm are required. In the literature, if we want a self-reconfiguration of micro robots to a target shape cons...

MEMS microrobots are low-power and low-memory capacity devices that can sense and act. One of the most difficult challenges in MEMS microrobot applications is the self-reconfiguration, especially when the efficiency, parallelism and the scalability of the algorithm are required. Self-reconfiguration with shared map does not scale. Because the map (...

This paper aims to solve the Radio Resource Management (RRM) problem for Multimedia Broadcast Multicast Service (MBMS) system in cellular network. We develop a flexible model to perform dynamic radio resource allocation for MBMS service by using metaheuristic approach. We conduct fitness landscape analysis to study the characteristics of the propos...

In this paper we present a mathematical modeling of Radio Resource Management (RRM) for multicast service diffusion based on Multimedia Broadcast Multicast Service (MBMS) standard. In this model, a flexible allocation approach named F2R2M is proposed, combining three candidate transport channels with scalable video transmission technology. The allo...

Self-reconfiguration for moving MEMS microrobots currently needs a positioning system and a map of the target shape. Traditional positioning solutions like GPS or multilateration are not applicable in the micro-world and maps sharing does not scale. In this paper we present self-reconfiguration method where nodes are unaware of their positions, and...

Over the last decades, research on microelectromechanical systems (MEMS) has focused on the engineering process which has led to major advances. Future challenges will consist in adding embedded intelligence to MEMS systems to obtain distributed intelligent MEMS. One intrinsic characteristic of MEMS is their ability to be mass-produced. This, howev...

The Multimedia Broadcast Multicast Service (MBMS) system supports efficient diffusion of multicast multimedia services in cellular networks. We develop a flexible model to perform dynamic radio resource allocation for MBMS service by using metaheuristic approach. We conduct fitness landscape analysis to study the characteristics of the proposed pro...

The major goal is to give an accurate position anywhere and at anytime with wireless positioning systems. Over the last decade, 802.11 networks have been added to the mobile technologies of mass (GSM, GPS). Positioning takes advantage of the massive deployment of wi-fi networks inside buildings and around them, in public places and also outside. Th...

Cooperative and distributed relocation strategy of multi-robot systems is a critical matter in self-reconfigurable modular robotic systems. In this paper, we depict a flexible distributed redeployment algorithm to relocate a large collection of micro-robots according to a list of desired final positions. Our algorithm is based on novel mechanisms r...

The contribution of this work is twofold. Firstly, we introduce a new channel assignment model for GSM radio networks. In this model both spatial and temporal variations of traffic are taken into account in order to improve network capacity and robustness. Secondly, using this model, we develop an original and effective hybrid algorithm to get high...

The problem considered in this paper consists in defining an assignment of frequencies to radio links between transmitters/receivers which minimize the global interference inside the network. This problem can be modeled as a Constraint Satisfaction Problem CSP. It is NP-hard and several results have been reported on techniques for solving it optima...

In this paper, we introduce one simple heuristic for value ordering in solving frequency assignment problem. Our approach is based on a special container to organize the values selection by jumping between two sides of domain. In order to reduce the time and space complexities of algorithm, we change the current value selection with last unchecked...

The problem considered in this paper consists in defining an assignment of frequencies to radio link between transmitters which minimize the number of frequency used to solve a CSP very well referenced as ROADEF’01 challenge. This problem is NP-hard and few results have been reported on techniques for solving it optimally. We applied to this versio...

In order to increase the effectiveness and the adaptability of methods, the constraints programming has gradually evolved to hybrid algorithms which combine exact and approximated methods in order to get the advantages of each of them. In this paper we propose a deterministic hybrid method which combines the backtracking, the constraints propagatio...

Frequency assignment is one of the main issues in radio networks planning. The multiple interferences are seldom taken into account in literature. There is not a framework with their modeling. A hypergraph modeling of the network gives a more realistic representation of this phenomenon. We generalize the T -coloring problem for graphs to hypergraph...

In this article we address the frequency management during WLAN planning. Frequency management refers to channels interference and SINR computation. We propose a new approach where location selection and frequency assignment are tackled together during WLAN planning process. Two steps characterize this approach. Firstly we use all the available cha...

Dans ce papier nous nous intéressons à la gestion de l’arbre de décision dans un algorithme hybride pour le CSP. Nous proposons une méthode déterministe qui permet de gérer dynamiquement des coupes dans l’arbre de recherche et l’accès aux variables de décision. Les deux principes sont basés sur la découverte et la mémorisation des associations vari...

The military radio stations with frequency hopping propose new problems of frequency assignment which must take into account the size of the deployment, the limited resources and also new interferences constraints on transmitters. This new problem is public since the publication [1] with a set of 10 instances. The computing resources and the comput...

Optimization methods based on complete neighborhood ex-ploration such as Tabu Search are impractical against large neighborhood problems. Strategies of candidate list propose a solution to reduce the neighborhood exploration complexity. We propose in this paper a generic Tabu Search algorithm using adaptive candidate list strategy based on two alte...

Standard tabu search methods are based on the complete exploration of current solution neighborhood. However, for some problems due to the neighborhood size or to the fitness evaluation complexity, the total exploration of the neighborhood is impractical. The main purpose of this paper is to propose a local search method with no enumeration procedu...

In this paper we focus on decision tree management for effectiveness enhancement of constraint programming hybrid algorithms. We propose a deterministic method that dynamically manages the cut of tree-branches and the access to the decision variables. Both principles are based on the discovery and the memorizing of variable/value associations that...

In this paper we focus on decision tree management for effectiveness enhancement of search within a new hybrid method. We propose a deterministic method that dynamically manages the cut of tree-branches and the access to the decision variables. Both principles are based on the discovery and the memorizing of variable/value associations that lead to...

Optimal planning of wireless networks is one of the most fundamental problems in WLAN design. This paper discusses the organisation of BSS in WLAN extended service set planning for large-scale deployment. We take advantage of a new geometric criterion to evaluate the coverage quality and apply them to WLAN planning. The obtained results show that u...

The two relevant stages in cellular network planning process arc the location selection of the transmitters and the frequency assignment. In the literature WLAN planning approach treats successively those two stages. In this article we propose a new approach where location selection and frequency assignment are tackled together during WLAN planning...

Standard tabu search methods are based on the complete exploration of current solution neighborhood. However, for some problems with very large neighborhood or time-consuming evaluation, the total exploration of the neighborhood is impractical. In this paper, we present an adaptive exploration of neighborhood using extension and restriction mechani...

Networks based on cellular concept suffer of bad performance when calls are done during handoff, i.e. during the transfers from one cell to another one. A part of these bad performances are due to the lack of management of overlapping area between cells. These imperfections find expression in cells discontinuity and distortion, in irregularity on i...

The resolution of workshop problems as the flow shop or the job shop has a great importance in industrial areas. Criteria to optimize are generally the minimization of the makespan time or the tardiness time. However, few resolution approaches take into account those different criteria simultaneously. This paper presents a comparative and progressi...

Cell capacity planning is a key phase of the expansion of cellular networks. The growth of communications demand requires improving the capacity of the networks regularly. However, cell capacity planning is difficult to achieve while it must take into account two conflicting objectives: minimising the blocking rate and reducing the interference. In...

The well-known fixed channel assignment scheme for cellular networks is not flexible enough to follow the evolution of traffic. This paper introduces a multi-period channel assignment model. In addition to the usual objective of minimizing the interference, the model integrates another requirement to minimize the transition cost from a frequency pl...

Introduction The vehicle routing problem (VRP) [2][5] is a logistical and distribution problem. It consists to schedule, at best, the path of a group of vehicles assuring the service of customers from a central store. The vehicles have a limited capacity that is generally insu#cient to satisfy all the customers. The more classical goals consist to...

We are interested in improving the quality of frequency assignment via a more accurate modeling of the traffic over the network. For this purpose, we propose here an original model for FAP, which takes into account both spatial and temporal variation of the traffic. The proposed model is assessed with a hybrid genetic algorithm and compared against...

The resolution of workshop problems such as the Flow Shop or the Job Shop has a great importance in many industrial areas. The criteria to optimize are generally the minimization of the makespan or the tardiness. However, few are the resolution approaches that take into account those different criteria simultaneously. This paper presents an approac...

Radio resources planning for frequency hopping military systems is very complex task due to the size of considered deployments, the radio resource limitations and the complexity of the radio phenomena to take into account. In this paper, we present some aspects of the local search algorithm proposed to deal with this problem. We focus more special...

Standard tabu search methods are based on the complete exploration of current solution neighborhood. However, for some problems with very large neighborhood or time-consuming evaluation, the total exploration of the neighborhood is impractical. In this paper, we present an adaptive exploration of neighborhood using extension and restriction mechani...