Technical Sessions A2 - E2

SESSION A2: Operational Research and Applications

[208] Traffic Control Model and Algorithm Based on Decomposition of MDP
Biao Yin, Mahjoub Dridi and Abdellah El Moudni

In this paper, a new method based on decomposition of Markov Decision Process (MDP) for traffic control at isolated intersection is proposed. The conflicting traffic flows should be grouped into different combinations which can occupy the conflict zone concurrently. Thus, for purpose of traffic delay reduction, the optimal policy of signal sequence and duration among different combinations is studied by minimizing the number of vehicles waiting in the queue. In order to reduce the computation of probabilities in large state transition matrix, the decomposition method proposed classifies states into several parts as rule of traffic signal transition. Each part contains the vehicle states in all traffic flows. This method firstly achieves the full-states calculation in stochastic traffic control system. Moreover, the simulation results indicate that MDP approach is more efficient to improve the performance of traffic control than other comparing methods, such as fixed-time control and actuated control.

[77] Traffic-aware Virtual Machine Placement in Geographically Distributed Clouds
Hana Teyeb, Ali Balma, Nejib Ben Hadj-Alouane, Samir Tata and Atidel B. Hadj-Alouane

In this work, we focus on the problem of virtual machines (VMs) placement in geographically distributed data centers, where tenants may require a set of networking VMs. The aim of the present work is to plan and optimize the placement of tenant’s VMs in a distributed Cloud environment while considering location and system performance constraints. Thus, we propose ILP formulations which have as objective the minimization of traffic generated by networking VMs and circulating on the backbone network. The different experiments conducted on the proposed formulations show the effectiveness of our model for large-scale Cloud systems in terms of running time and computational resources.

[103] A mixed integer linear programming approach for a new form of facility layout problem
Yipei Zhang and Ada Che

This paper aims to study a new form of facility layout problem, in which the building has already been constructed and the specific room layout inside has been determined. Unlike the traditional facility layout problem, what we take into account is how to assign a certain number of rooms to a given number of departments with the purpose of maximizing the utilization rate of the rooms. This is equivalent to minimizing the total difference value between the extra area of different departments after satisfying their required area, thus reducing the space waste. To solve this special combinatorial optimization problem, we develop a Mixed-Integer Linear Programming (MILP) model. The model is solved using commercial software CPLEX14.0. Computational results on several randomly generated instances demonstrate the effectiveness of the proposed approach.

[85] Lagrangian relaxation for the permutation flowshop scheduling problem with minimal and maximal time lags
Imen Hamdi and Taicir Loukil

In this research, we are interested in the permutation flowshop scheduling problem with minimal and maximal time lags while minimizing the total tardiness. The processing order of jobs is to be the same for each machine. The time lag is defined as the waiting time between two consecutive operations of each job. It is greater than or equal to a prescribed value called minimal time lag and smaller than or equal to a prescribed value called maximal time lag. A new mathematical formulation is proposed. Then, a new lower bound is derived by applying the Lagrangian relaxation. In order to make this technique a viable approach to the considered problem, an auxiliary formulation is adopted and the Lagrangian multipliers are updated using the subgradient algorithm. Then, results of the computational experiments are reported.

SESSION B2: Robust Control and its applications

[49] Sensor Position Influence on Modeling and Control of 155mm Canard-Guided Spin-Stabilized Projectiles
Florian Seve, Spilios Theodoulis, Philippe Wernert, Michel Zasadzinski and Mohamed Boutayeb

This article explores in detail the influence of the sensor position on the pitch/yaw dynamics modeling and on the autopilot design and performance for a 155mm canard-guided spin-stabilized projectile which incorporates a nose-mounted course correction fuse (CCF) for trajectory correction. A complete and exact nonlinear model is given and used for computing a q-LPV model necessary for the controller synthesis. Using this linearized model, the influence of the sensor position on the load factor-related open-loop dynamics is highlighted. The Hinf loop-shaping design approach, which permits to obtain a highperformance, robust, fixed structure and fixed order controller for any operating point, is presented. The necessity, for the controller synthesis, of considering the actual sensor position in the projectile nose and of calculating the load factor feedback signals at the center of gravity (CG) using the load factors actually measured at the CCF, in order to cope with this important practical constraint, is demonstrated.

[98] Experimental Second Order Sliding Mode Fault Tolerant Control for Moment Gyroscope System with Sensor Fault
Ahmed Chaibet and Moussa Boukhnifer

The paper proposes and evaluates an experimental passive sensor fault tolerant control for a gyroscope system. The sensor fault occurrence reduces the performance and may even cause the instability. This work focuses on developing fault tolerant control when these drawbacks are occurred. A passive fault tolerant control (PFTC) scheme is developed to counteract a sensor failure and parameters uncertainties. A second sliding mode FTC strategy based on super twisting algorithm ensures the stability robustness of the gyroscope system in the presence of the additive faults. For this purpose, the passive fault tolerant control (PFTC) approach is designed to preserve the stability and to maintain an acceptable performance when the sensor failure appears. The effectiveness of the proposal fault tolerant control strategy is validated by simulation and experiment results in presence of the sensor fault.

[191] Performance Evaluation of Low Earth Orbit Microsatellite Attitude Control Systems Using Tetrahedral Configuration – A Comparative Study
Mohammed Arezki Si Mohammed, Abdelatif Bellar, Youcef Benttoutou, Abdelmadjid Boudjemai, Rima Roubache and Nsreddine Taleb

This paper presents an analysis and comparison of attitude control systems of low Earth obit microsatellites based on different reaction wheel configurations. Two configurations are presented, four reaction wheels configuration named tetrahedral configuration and classical three reaction wheels configuration. Three control algorithms, Proportional Derivative, Sliding Mode, and Feedback Linearization using Euler angle formulation with different reaction wheel configurations are compared in terms of the settling time and power efficiency. Numerical analysis clearly indicates that the tetrahedral configuration with PD controller is a more logical choice for optimal 3-axis attitude maneuver for low Earth orbit microsatellite than the classical three reaction wheels. Also, the results prove that the controllers show the capability of providing accuracy better than 0.015 deg in attitude and 0.015 milli-deg/sec in rate.

[93] A genetic algorithm to minimise the makespan on two dedicated processors
Adel Kacem and Abdelaziz Dammak

The studied problem is to optimize a production system where these systems have two dedicated processors. The assignment of tasks to these processors is fixed. For this problem, we have three types of tasks. Some tasks must be processed only by the first processor, a few others by the second processor and the remaining tasks need simultaneously both processors. This NP-hard problem requires the use of well-adapted methods. We have studied the design of genetic algorithms which have been very successful in solving optimization problems. This can be justified by the quality of the solution obtained by such methods and the efficiency in terms of computation time.

SESSION C2: System Control

[122] On the use of ARMAX approach for handwriting system modelization
Maroua El Kastouri, Afef Abdelkrim and Mohamed Benrejeb

Modeling handwriting system allows studying movements of the hand and its control signals as integrated electromyographic signals (IEMG) which are detected during muscle contraction involved in the act of writing. Reconstruction of muscle stimuli from written application can have a very important impact especially for the design of support systems for the disabled. In this paper, we propose a new mathematical model to estimate this muscle signal based on identification parameters of the discrete time system, using Auto-Regressive Average with eXternal inputs (ARMAX) models and the Recursive Least Squares algorithm (RLS).

[160] On the design of process fuzzy PID controller
Mohamed Amine Ben Brahim, Afef Abdelkrim and Mohamed Benrejeb

This paper deals with the PID controller proportional, integral and derivative parameters characterize-ation. After performances comparison between classical and fuzzy PID, the idea is to determine a partial fuzzy PID controller. When only the proportional parameter is fuzzified, results show that the approach is efficient and can be sufficient to impose robustness for the closed loop system. The approach is tested, with success, for linear and non linear system.

[240] A Lyapunov Based PI Controller with an Anti-windup Scheme for a Purification Process of Potable Water
Paolo Mercorelli, Johannes Goes and Robert Halbe

This paper deals with a parameter set up of a PI controller to be applied in an system for the regeneration of potable water. The used PI controller is a nonlinear one and its nonlinearity consists of the positiveness of its output. Moreover, an anti-windup control structure is considered to manage saturation effects. In order to analyse the stability and the dynamic performance of the controlled system a Lyapunov approach is proposed. Through this approach the condition of the three parameters which characterise the controller (PI and anti-windup scheme) are calculated to obtain a compromise between a stability and fast dynamics. Simulations using real parameters of the system are shown.

[168] Robust EP-contaminated filter for discrete-time systems
Eric Blanco, Philippe Neveux and Abdelhani Boukrouche

The robust filtering problem for uncertain discrete-time systems is treated in this paper. An EP-contaminated framework is adopted to design the robust filter in presence of model uncertainties. The result is presented in term of Toeplitz matrix equations. The proposed approach does not require a formal modelling of uncertainties. Meanwhile, the EP-contaminated robust filter is equivalent to the minimum variance filter with a stochastic representation of the uncertainties. An example shows the effectiveness of the approach.

SESSION D2: Healthcare systems planning and optimization

[29] Ranking the solution techniques for reactive scheduling problem in operating room
Vahid Farrokhi, Francine Herrmann, Imed Kacem and László Pokorádi

The main aim of this paper is to express the techniques which can solve reactive scheduling problem in operating room and then compare them for ranking. On the one hand importance of scheduling for operating rooms in hospitals is increasing for the reasons like hospitals reputations and expenses and on the other hand in real world, scheduling of operating rooms is not often static. Hence, the authors have made an endeavor to show the reactive scheduling in this field. There are many techniques and methods to solve the problem, but academics and practitioners are concerned with the best techniques in this field. Therefore, an attempt has been made to represent and compare and rank the most common techniques by applying the analytic hierarchy process (AHP) and fuzzy technique for order preference by similarity to ideal solution (TOPSIS).

[244] MILP for Synchronized-mTSPTW: application to Home HealthCare Scheduling
Malek Masmoudi and Racem Mallouli

The Multiple Traveling Salesmen Problem is to deliver goods to a set of customers thanks to several travelling salesmen with known demands within minimizing the total salesman transportation cost while satisfying the delivery demands. Here, each salesman has own subset of unordered customers that is determined in advance. Many variants of this problem with different formulations and solution methods are provided in literature. In particular, the Synchronized m-TSP is defined where some customers are common for more than one salesman and must be visited at the same time, simultaneously and not in sequence, by these salesmen to be entirely served. In general, a service or a visit’ processing time is defined for each customer. The Synchronized m-TSPTW considering synchronization and time windows constraints is defined in Dohn (2011). This paper deals with Synchronized-mTSPTW within an application to Home Health Care (HHC) scheduling problem. Vehicles and customers are modified respectively by caregivers and patients. Time windows and synchronization are given as patients’ availability preferences and caregivers’ synchronization. The Synchronized-mTSPTW is NP-hard since TSPTW is NP-Hard. MILP models are provided for the same problem by Kergosien et al (2009) and Di Mascol et al. (2014) with limitations in term of computation time. In this paper, we provide an efficient MILP considering the HHC scheduling problem as a special Resource-Constrained Project Scheduling Problem (RCPSP) with fixed resources (patients) and mobile resources (caregivers). A derived two-stages LP heuristic is also provided to improve the computation times, especially for big instances.

[149] A dichotomic algorithm for an operating room scheduling problem
Mohamed Amine Abdeljaoued, Zied Bahroun and Nour Houda Saadani

In this paper, we study an NP-hard operating room scheduling problem, consisting in a set of operations which have to be scheduled on identical operating rooms. In this problem, the operations are divided in groups; each one should be achieved by a single surgeon. The objective is to minimize the global completion time of the operations. We start by providing a mathematical model inspired from the two-dimensional Strip Packing problems and we compare its performances to the classical formulation. Then we introduce a dichotomic algorithm that we use to solve some larger instances of the problem.

[224] An optimization and Simulation approach for Operating Room scheduling under stochastic durations
Hadhemi Saadouli, Malek Masmoudi, Badreddine Jerbi and Abdelaziz Dammak

Several variants of the Operating room scheduling problem are provided in literature for different contexts. In Tunisia, especially in Habib Bourguiba Hospital in Sfax, Open scheduling policy is considered to schedule elective surgeries. In Orthopedic service, operating room scheduling is carried out weekly. Three operating rooms are available and one of them is assigned to a special kind of surgeries called septic. At the tactical level, elective operations are assigned to weeks so that the workload (average) by week is approximately equal to the weekly capacity. Once the set of operations to be carried out in a week are selected, we choose at the operational level to which day and which room the operations are assigned and in which order. As patients are asked to come to the hospital in the morning, the best scheduling is the one that minimizes the patients waiting time. The average of the operations durations are considered for planning and scheduling. Nevertheless, such information is uncertain and generally represented by a probability distribution (normal). In this paper, we provide a MILP to model this problem and solve it using Cplex and then a simulation model is used to evaluate the robustness of the provided solutions.

SESSION E2: Communications, Image and signal processing

[125] Visualization of Faces from Surveillance Videos via Face Hallucination
Adam Makhfoudi, Sumaya Almaadeed, Richard Jiang, Graham Sexton and Ahmed Bouridane

Face hallucination can be a useful tool for visualizing a low quality face into a visually better quality, making it an attractive technology for many applications. While faces in surveillance videos are usually at very low resolution, in this paper, we propose to use face hallucination technology to visualize faces from visual surveillance systems, and develop a weighted scheme to enhance the quality of face visualization from surveillance videos. Our experiment validated that in comparison with the classic eigenspace based face hallucination, our proposed weighted face hallucination strategy can help improve the overall quality of a facial image extracted from surveillance footage.

[145] A New Image Crypto-compression System SPIHT-PSCS
Tarek Hadjem, Mohamed Azzaz, Camel Tanougast and Said Sadoudi

In this paper, a new algorithm combined compression and image encryption is presented. The compression is based on a hierarchical structure called SPIHT(Set Partitioning in Hierarchical Trees). This compression is followed by an encryption scheme PSCS (Parametric Switching Chaotic System). The performances of this technique were evaluated in terms of compression quality and data security. Simulation results have shown the effectiveness of this technique, and thereafter, it is ready for a hardware implementation.

[148] A Low-Cost Many-to-One WSN Architecture Based on UWB-IR and DWPT
Mohamed Tabaa and Camille Diou

The main objective of this research work is to propose a new method of communication adapted to sensor networks for both one-to-many and many-to-one topologies. This type of networks is characterized by its price, its size and its energy consumption. In the last few years, several recent developments concern these networks but rare of them propose a complete and functional architecture. The challenge of this work consists in proposing a new architecture for impulse communication based on the wavelet transform for both generation of pulses and detection of the information. This architecture is adapted to the low throughput short-range applications and is scalable according to the type of use but also the number of sensors.

[190] High Gain Channel Coding for Satellite Communication System
Lahcen Hadj Abderrahmane and Mansour Bacha

The main aim of this work is to find a way to replace the current coding scheme implemented on AlSat-2; the second earth observation Algerian Microsatellite (2.5 m of resolution), to be implemented on the future high resolution earth observation Algerian Microsatellite, by the discovered Turbo Codes. This paper describes the performance of the Turbo Code – Binary Phase Shift Keying (BPSK) Modem which was designed at the Centre of Satellite Development (CDS). This proof–of–concept modem is the outcome of a research and development (R&D) project entitled “Design of a smart adaptive communication system for the future satellite communication systems”. The major technical contribution of this work is the new interleaver design using chaotic sequences to produce the dither in the golden interleaver. We compare the performance of Turbo codes for different interleaver sizes and a number of iteration equal to five with the performance of the industry standard rate 1/2, constraint length (K) seven, convolutional code. As example and for practical considerations, the interleaver length is fixed to be equal to 1024. To achieve a bit error rate (BER) of 10-5, a gain of about 3dB is reached when we replace the current scheme (convolutional encoder) with the suggested Turbo encoder.