CNRS System Conception, Modelisation, and Optimsation Laboratory

Nancy, France

CNRS System Conception, Modelisation, and Optimsation Laboratory

Nancy, France

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Hadj-Abdelkader A.,Abou Bekr Belkaid University Tlemcen | Cherki B.,Abou Bekr Belkaid University Tlemcen | Bourhis G.,CNRS System Conception, Modelisation, and Optimsation Laboratory
International Conference on Virtual Rehabilitation, ICVR | Year: 2015

We address the problem of driving a powered wheelchair (PW) using the 3D haptic device PHANToM Omni. The driver uses this force feedback device to designate the desired speed and rate of turn for the PW. A sensor on the wheelchair is used to measure obstacle distance. We describe a strategy to convert distance into forces which are reflected to the operator's hand, via the haptic interface. This haptic information provides feedback to the driver in addition to the view he has on the environment. Experiments show that this haptic feedback significantly improves operator's performance in terms of reduction in navigation time, collisions and workload. © 2015 IEEE.


Kacem I.,CNRS System Conception, Modelisation, and Optimsation Laboratory | Rapine C.,University of Lorraine
CIE 2016: 46th International Conferences on Computers and Industrial Engineering | Year: 2016

In this paper we consider the open shop scheduling problem where the jobs have delivery times. The minimization criterion is the maximum lateness of the jobs. This problem is knwon to be NP-hard, even restricted to only 2 machines. We establish that any list scheduling algorithm has a performance ratio of 2. For a fixed number of machines, we design a polynomial time approximation scheme (PTAS) which represents the best possible result due to the strong NP-hardness of the problem.


Kacem I.,CNRS System Conception, Modelisation, and Optimsation Laboratory | Kadri A.,CNRS System Conception, Modelisation, and Optimsation Laboratory | Laroche P.,CNRS System Conception, Modelisation, and Optimsation Laboratory
CIE 2016: 46th International Conferences on Computers and Industrial Engineering | Year: 2016

This study addresses a 2-steps procedure applied to the inventory regulation problem in bicycle sharing-systems. The objective is to balance a network consisting of set of stations by using a single vehicle, with the aim of minimizing the waiting times during which the stations remain imbalanced. The balancing operations can be complex, especially when the network size is large. To solve the problem, we propose an approach based on different steps. First, the network is split into multiple zones according to fixed heights and widths. Secondly, the balancing problem is solved for each zone. Finally, the order in which the zones must be visited is defined. To solve these problems, we propose two heuristic algorithms based on the genetic algorithm and the nearest neighbour search method. The proposed procedure is simple and efficient, and presents some advantages with respect to the balancing considering a single area, in particular for large networks. Indeed, the numerical results show that the proposed regulation methodology has a lower computational cost and provides improved results compared to those when balancing a single area.


Habert O.,CNRS System Conception, Modelisation, and Optimsation Laboratory | Gam M.,CNRS System Conception, Modelisation, and Optimsation Laboratory | Kacem I.,CNRS System Conception, Modelisation, and Optimsation Laboratory
CIE 2016: 46th International Conferences on Computers and Industrial Engineering | Year: 2016

In this paper, we propose a solution to rank some chosen communication and information assistive technologies by using the well-known Multiple Criteria Decision-Making tool: fuzzy TOPSIS. There are many ways to restore or to assist disabled people in their daily communication and quest of information. Thanks to New Information and Communication Technologies (NICTs), communication assistive technology has started the path of a deep evolution. Indeed, numerous assistive devices using web technology and connected objects can be found. The main goal of this work is to propose assistive technology designer a tool to make prospective studies to guide them in their strategy and choice of new products' development. One of the advantages of MCDM method is to process with data coming from the disabled users, healthcare and social staff, researchers...


Becker M.,Leibniz University of Hanover | Ginoux N.,University of Lorraine | Martin S.,CNRS System Conception, Modelisation, and Optimsation Laboratory | Roka Z.,CNRS System Conception, Modelisation, and Optimsation Laboratory
2016 IEEE International Conference on Systems, Man, and Cybernetics, SMC 2016 - Conference Proceedings | Year: 2016

One important aim in tire industry when finalizing a tire design is the modeling of the noise characteristics as received by the passengers of the car. In previous works, the problem was studied using heuristic algorithms to minimize the noise by looking for a sequence under constraints. These constraints are imposed by tire industry. We present a new technique to compute the noise. We also propose an integer linear program based on that technique in order to solve this problem and find an optimal sequence. Our study shows that the integer linear programming approach shows significant improvement of the found tire designs, however it has to be improved further to meet the calculation time restrictions for real world problem size. © 2016 IEEE.


Bousefsaf F.,CNRS System Conception, Modelisation, and Optimsation Laboratory | Maaoui C.,CNRS System Conception, Modelisation, and Optimsation Laboratory | Pruski A.,CNRS System Conception, Modelisation, and Optimsation Laboratory
Biomedical Signal Processing and Control | Year: 2013

Photoplethysmographic signals obtained from a webcam are analyzed through a continuous wavelet transform to assess the instantaneous heart rate. The measurements are performed on human faces. Robust image and signal processing are introduced to overcome drawbacks induced by light and motion artifacts. In addition, the respiration signal is recovered using the heart rate series by respiratory sinus arrhythmia, the natural variation in heart rate driven by the respiration. The presented algorithms are implemented on a mid-range computer and the overall method works in real-time. The performance of the proposed heart and breathing rates assessment method was evaluated using approved contact probes on a set of 12 healthy subjects. Results show high degrees of correlation between physiological measurements even in the presence of motion. This paper provides a motion-tolerant method that remotely measures the instantaneous heart and breathing rates. These parameters are particularly used in telemedicine and affective computing, where the heart rate variability analysis can provide an index of the autonomic nervous system. © 2013 Elsevier Ltd. All rights reserved.


Kadri A.A.,CNRS System Conception, Modelisation, and Optimsation Laboratory | Kacem I.,CNRS System Conception, Modelisation, and Optimsation Laboratory | Labadi K.,CNRS System Conception, Modelisation, and Optimsation Laboratory
Computers and Industrial Engineering | Year: 2016

Bicycle sharing systems are transportation systems that allow the users to rent a bicycle at one of many automatic rental stations scattered around the city, use them for a short travel and return them at any station. A crucial factor for the success of such a system is its ability to ensure a good quality of service to users. It means the availability of bicycles for pick-up and free places to return them. This is performed by means of a rebalancing operation, which consists in removing bicycles from some stations and transferring them to other stations, using dedicated vehicles. In this paper, we study the rebalancing vehicles routing problem by considering the static case. Vehicles conduct tours between stations to return them to their desired levels, which are known in advance, and each station must be visited exactly once and only once by a vehicle. This problem is similar to the traveling salesman problem with additional constraints. The aim is to find an optimal scheduling of the vehicle that minimizes the total waiting time of the stations in disequilibrium states. We propose several lower and upper bounds. These bounding procedures are used in a branch-and-bound algorithm. Computational experiments are carried out on a large set of instances and the obtained results show the effectiveness of our method. © 2016 Elsevier Ltd.


Kacem I.,CNRS System Conception, Modelisation, and Optimsation Laboratory
2013 2nd International Conference on Systems and Computer Science, ICSCS 2013 | Year: 2013

In this paper, we consider some practical scheduling problems under unavailability constraints (break-down periods, maintenance durations and/or setup times). Such problems can be met in different industrial environments and be associated to numerous real-life applications. The studied criteria are related to the maximum lateness minimization. The paper is organized in two main parts. The first part focuses on some special cases (makespan minimization when tails are equal and maximum lateness minimization when release dates are equal (see Section 2). The second part is devoted to the maximum lateness minimization (see Section 3). In each part, we present the main contributions and explain their principles (complexity results, heuristic algorithms and their worst-case performance, existing approximation schemes, exact methods, dynamic programming,...), Finally, Section 4 concludes the paper. © 2013 IEEE.


Habbas Z.,CNRS System Conception, Modelisation, and Optimsation Laboratory | Amroun K.,University of Abderrahmane Mira de Béjaïa | Singer D.,CNRS System Conception, Modelisation, and Optimsation Laboratory
RAIRO - Operations Research | Year: 2016

Many real-world problems can be modelled as Constraint Satisfaction Problems (CSPs). Although CSP is NP-complete, it has been proved that non binary CSP instances may be efficiently solved if they are representable as Generalized Hypertree Decomposition (GHD) with small width. Algorithms for solving CSPs based on a GHD consider an extensional representation of constraints together with join and semi-join operations giving rise to new large constraint tables (or relations) needed to be temporarily saved. Extensional representation of constraints is quite natural and adapted to the specification of real problems but unfortunately limits significantly the practical performance of these algorithms. The present work tackles this problem using a compact representation of constraint tables. Consequently, to make algorithms compatible with this compact representation, new "compressed join" and "compressed semi-join" operations have to be defined. This last step constitutes our main contribution which, as far as we know, has never been presented. The correctness of this approach is proved and validated on multiple benchmarks. Experimental results show that using compressed relations and compressed operations improves significantly the practical performance of the basic algorithm proposed by Gottlob et al. for solving non binary CSPs with a Generalized Hypertree Decomposition. © 2016 EDP Sciences, ROADEF, SMAI.


Bousefsaf F.,CNRS System Conception, Modelisation, and Optimsation Laboratory | Maaoui C.,CNRS System Conception, Modelisation, and Optimsation Laboratory | Pruski A.,CNRS System Conception, Modelisation, and Optimsation Laboratory
Proceedings of the 2013 7th International Conference on Pervasive Computing Technologies for Healthcare and Workshops, PervasiveHealth 2013 | Year: 2013

In the present paper, we introduce a new framework for detecting workload changes using video frames obtained from a low-cost webcam. The measurements are performed on human faces and the proposed algorithms were developed to be motion-tolerant. An interactive Stroop color word test is employed to induce stress on a set of twelve participants. We record the skin conductance and compare these responses to the stress curve assessed by a webcam-derived heart rate variability analysis. The results offer further support for the applicability of stress detection by remote and low-cost means, providing an alternative to conventional contact techniques. © 2013 ICST.

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