- Mathematics, History of Mathematics, Manuscript Studies, History, Hystory, Operation Research, and 14 moreManuscripts (Medieval Studies), Soufisme, History of Islam, Berber studies, Al Andalus (Islamic History), Early Islamic History, Berber, Histoire des idées et de la pensée, Maghreb studies, Algeria, History of Islamic Civilization, Medieval Historiography, History of the Mediterranean, and Operations Researchedit
- Djamil Aïssani was born in 1956 in Biarritz (Basque Country, France). He started his career at the University of Cons... moreDjamil Aïssani was born in 1956 in Biarritz (Basque Country, France). He started his career at the University of Constantine in 1978. He received his Ph.D. in 1983 from Kiev State University (Soviet Union). He is at the University of Bejaia since its opened in 1983/1984. Director of Research, Head of the Faculty of Science and Engineering Science (1999–2000), Director of the Research Unit LAMOS (Modeling and Optimization of Systems, http://www.lamos.org), Scientific Head of the Doctoral Computer School (2004 - 2011), he has taught in many universities (U.S.T.H.B. Algiers, University of Annaba, University of Montpellier, University of Rouen, University of Tizi Ouzou, I.N.H. Boumerdès, University of Bourgogne, University of Sétif, ENITA Bordj-el-Bahri, I.N.P.S. Ben Aknoun, Algiers Polytechnical School, Georgia Tech Atlanta, E.H.E.S.S. Paris, C.N.A.M. Paris,...). He has published many papers on Markov chains, queueing systems, reliability theory, performance evaluation and their applications in such industrial areas as electrical networks and computer systems. Prof. Aissani was the president of the National Mathematical Committee (Algerian Ministry of Higher Education and Scientific Research, 1995 – 2005).edit
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The aim of this work is the study of the impact of interferences on the link disconnection probability in Ad hoc networks. We first calculated the critical distance for successful transmission. Then we modeled the motion of an ad hoc... more
The aim of this work is the study of the impact of interferences on the link disconnection probability in Ad hoc networks. We first calculated the critical distance for successful transmission. Then we modeled the motion of an ad hoc nodes using a Markov process of {Xn} ({Yn}), and under the assumption that the Hello messages arrive according to a Poisson process with rate λ, we calculated the probability that a link becomes unavailable by exploiting data Hello messages like node position and node speed.
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Time Slotted Channel Hopping (TSCH) is one of the Medium Access Control methods proposed in the IEEE 802.15.4e standard to deal with the requirements of the industrial Wireless Sensor Networks (WSNs), especially in terms of high... more
Time Slotted Channel Hopping (TSCH) is one of the Medium Access Control methods proposed in the IEEE 802.15.4e standard to deal with the requirements of the industrial Wireless Sensor Networks (WSNs), especially in terms of high reliability and low latency. The key feature of the TSCH method is the combination between a time slotted access with a channel hopping, while considering both shared and dedicated links. The latter are essential for ensuring transmissions without loss and additional delays. Therefore, the objective we are seeking to reach in this paper is to demonstrate the benefit use of dedicated links on industrial WSNs-based 802.15.4e TSCH method. To this end, we propose an analytical model-based Markov chains for the TSCH method taking into account the dedicated links, and we estimate the transmission probability $$\tau $$ τ of a data packet. The latter will be then used to develop others analytical models, in order to derive a number of performance metrics, namely the average access delay, the reliability, the throughput, and the energy consumption. Furthermore, to validate the analytical model, we perform extensive simulations-based Monte-Carlo. Finally, to give credibility to the obtained simulation results, we compute $$95\%$$ 95 % confidence intervals. Numerical results show that increasing the number of dedicated links reduces significantly the retransmission probability offering best network performances in terms of average access delay, reliability and throughput.
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This paper addresses the problem of optimal router nodes placement (RNP) in a wireless mesh network. This issue consists to determine the optimal positions of mesh routers that allow the optimization of the network performance with... more
This paper addresses the problem of optimal router nodes placement (RNP) in a wireless mesh network. This issue consists to determine the optimal positions of mesh routers that allow the optimization of the network performance with regards to client coverage and network connectivity. To solve this issue, a bio-inspired algorithm, called Firefly optimization algorithm, has been applied since it is an NP-hard issue. The obtained results demonstrate the effectiveness of our proposed approach when compared to the existing genetic algorithm.
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In the context of mobile computing, the cache memory technique turns out to be the most widely used and the most effective solution to improve several quantities, namely: (1) the bandwidth consumption, (2) the information availability,... more
In the context of mobile computing, the cache memory technique turns out to be the most widely used and the most effective solution to improve several quantities, namely: (1) the bandwidth consumption, (2) the information availability, and (3) the node latency. particularly in the Internet of Things (IoT) environment, where objects have limited storage and computing capacities. However, this solution may cause some cache management issues, specifically data consistency and data replacement. In this paper, we strive to assess the relationship between the consistency mechanism’s performance and the implemented replacement strategy and determine whether they are correlated or not. Afterward, we focus on improving the caching consistency mechanism’s performance based on the Time To Live principle (TTL) using the IoT-Data lifetime and the data Variable-TTL. Therefore, two based-TTL consistency mechanisms were implemented and evaluated using three replacement strategies: LFU (Least Frequently Used), LRU (Least Recently Used), and LFRU (Least Frequently Recently Used). The simulation experiments show that the consistency mechanism performance strongly depends on the implemented replacement strategy, which can significantly improve the performance, particularly in terms of data availability and end-user latency. In addition, the relative frequency and the variable-TTL considerably improve the wireless mobile caching performance.
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The placement of mesh routers in a mobile mesh network strongly influences the network performance. In particular, when the mesh clients are mobile, this deployment issue becomes more difficult to solve since mesh routers should adapt... more
The placement of mesh routers in a mobile mesh network strongly influences the network performance. In particular, when the mesh clients are mobile, this deployment issue becomes more difficult to solve since mesh routers should adapt their locations to the dynamic network topology. In this letter, we propose to apply a simulated annealing algorithm to deal with the dynamic router node placement issue. The performance metrics considered when deploying these routers are: client coverage, network connectivity, and the average distance traveled by routers. Simulation results show a significant performance improvement in terms of client coverage and network connectivity and a considerable decrease in router movements.
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The proliferation of web services-based applications, collaboration, interoperability between companies, and more generally demands of web services over the internet are major challenges in the design of performance evaluation in web... more
The proliferation of web services-based applications, collaboration, interoperability between companies, and more generally demands of web services over the internet are major challenges in the design of performance evaluation in web services discovery and composition. It is required for the web services providers to analyse the performance related to the satisfaction of clients requests. This paper presents an analytical model based on Petri nets, for evaluating the performance of a web services system where requests and web services follow an exponential server. The arrival process of the users requests and web services follows a Poisson distribution. When the web services finish the service, they join the queue. This model follows a Poisson distribution, it is based on Petri nets. We use an analytical method for solving the model. Furthermore, we compute the system's response time, and the average number of clients in the system in terms of the arrival rate of clients requests. We find the limit number of clients in the system from which it begins to be saturated.
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The calculation of the stationary distribution for a stochastic infinite matrix is generally difficult and does not have closed form solutions, it is desirable to have simple approximations converging rapidly to this distribution. In this... more
The calculation of the stationary distribution for a stochastic infinite matrix is generally difficult and does not have closed form solutions, it is desirable to have simple approximations converging rapidly to this distribution. In this paper, we use the weak perturbation theory to establish analytic error bounds for the M/G/1 model. Numerical examples are carried out to illustrate the quality of the obtained error bounds.
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In this work, we considered the parametric estimation of the characteristics of the M / M / 1 / N {M/M/1/N} waiting model with Bernoulli feedback. Through a Monte-Carlo simulation study, we have illustrated the effect of the estimation of... more
In this work, we considered the parametric estimation of the characteristics of the M / M / 1 / N {M/M/1/N} waiting model with Bernoulli feedback. Through a Monte-Carlo simulation study, we have illustrated the effect of the estimation of the starting parameters of the considered waiting system on the statistical properties of its performance measures estimates, when these latter are obtained using the plug-in method. In addition, several types of convergence (bias, variance, MSE, in law) of these performance measure estimators have also been showed by simulation.
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In this work, we derive insensitive bounds for various performance measures of a single-server retrial queue with generally distributed inter-retrial times and Bernoulli schedule, under the special assumption that only the... more
In this work, we derive insensitive bounds for various performance measures of a single-server retrial queue with generally distributed inter-retrial times and Bernoulli schedule, under the special assumption that only the customer at the head of the orbit queue (i.e., a FCFS discipline governing the flow from the orbit to the server) is allowed to occupy the server. The methodology is strongly based on stochastic comparison techniques. Instead of studying a performance measure in a quantitative fashion, this approach attempts to reveal the relationship between the performance measures and the parameters of the system. We prove the monotonicity of the transition operator of the embedded Markov chain relative to strong stochastic ordering and increasing convex ordering. We obtain comparability conditions for the distribution of the number of customers in the system. Bounds are derived for the stationary distribution and some simple bounds for the mean cha...
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In this article, a queueing inventory system with finite sources of demands, retrial demands, service time, lead time, ( s , S ) \left(s,S) replenishment policy, and demands search from the orbit was studied. When the lead time is... more
In this article, a queueing inventory system with finite sources of demands, retrial demands, service time, lead time, ( s , S ) \left(s,S) replenishment policy, and demands search from the orbit was studied. When the lead time is exponentially distributed (resp. lead time is generally distributed), generalized stochastic Petri net (GSPN) (resp. Markov regenerative stochastic Petri net [MRSPN]) is proposed for this inventory system. The quantitative analysis of this stochastic Petri net model was obtained by continuous time Markov chain for the GSPN model (resp. the supplementary variable method for the MRSPN model). The probability distributions are obtained, witch allowed us to compute performance measures and the expected cost rate of the studied system.
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Dans ce chapitre, nous présentons une synthèse des résultats sur l’application de la méthode de stabilité forte à l’étude de la robustesse des systèmes et des réseaux de files d’attente. En plus de l’affirmation qualitative de la... more
Dans ce chapitre, nous présentons une synthèse des résultats sur l’application de la méthode de stabilité forte à l’étude de la robustesse des systèmes et des réseaux de files d’attente. En plus de l’affirmation qualitative de la stabilité forte, nous obtenons souvent des bornes de perturbation. Enfin, l’utilisation des méthodes d’estimation non paramétrique de densité dans ce contexte est discutée.
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The new generation WiFi (Widely Fidelity), which is called 802.11ac, has the goal of reaching at least 1 Gbps on bands below 6 GHz. This is why, the standard has been extended with new features at both PHYsical (PHY) and Medium Access... more
The new generation WiFi (Widely Fidelity), which is called 802.11ac, has the goal of reaching at least 1 Gbps on bands below 6 GHz. This is why, the standard has been extended with new features at both PHYsical (PHY) and Medium Access Control (MAC) layers level. One of the key features of MAC layer is the ability of aggregating frames in order to reduce temporal overheads that significantly harm the performance of 802.11 networks. Three forms of aggregation exist, namely Aggregate MAC Service Data Unit (A-MSDU), Aggregate MAC Protocol Data Unit (A-MPDU) and hybrid A-MSDU/A-MPDU Aggregation (A-hybrid). In this paper, we study the impact of Frame Aggregation Mechanisms (FAMs) for improving the overall throughput of 802.11ac networks. Furthermore, we highlight the need of PHY/MAC cross-layer communications for optimizing the wireless bandwidth utilization. Simulation results demonstrate the gains offered by the FAMs.
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In this paper, we present the Aristotelian theory of comets, which is well known in the Muslim West through the commentaries of Ibn Rušd and Ibn Bāǧǧa. This aspect is covered three centuries later in an unknown manuscript attributed to... more
In this paper, we present the Aristotelian theory of comets, which is well known in the Muslim West through the commentaries of Ibn Rušd and Ibn Bāǧǧa. This aspect is covered three centuries later in an unknown manuscript attributed to the famous mathematician Ibn Ġāzī al-Miknāsī (1437-1513), and this text is not present in the known list of his works. The author devotes a part of his manuscript to the comet astrology following Ptolemy, and introduces a critical position of Iḫwān al-Ṣafā’, characterized by the rejection of the sidereal comets idea. We are also interested in comet classifications given by Ibn Ġāzī and another author ‘Alī al-Antākī. We found that the content of the De cometis of pseudo-Ptolemy is analogous with the text of Ibn Ġāzī, and almost identical to the text of al-Antākī. Then, we are interested in observations of comets from the 9th to the end of the 19th century in North Africa and in Islamic Spain (Andalusia), recorded in some Arabic manuscripts on astronomy...
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Research Interests: Psychology and Philosophy
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La modelisation analytique par Chaine de Marcov et l'analyse des performances de la norme IEEE 802.15.4 a ete le sujet de recherche de plusieurs articles publies dans la litterature. Les modeles s'inspirent principalement des... more
La modelisation analytique par Chaine de Marcov et l'analyse des performances de la norme IEEE 802.15.4 a ete le sujet de recherche de plusieurs articles publies dans la litterature. Les modeles s'inspirent principalement des modeles de la norme IEEE 802.11 qui supposent que le canal de transmission est ideal, or que le canal est sujet a des perturbations et ne peut pas etre ideal a tout moment. La sous-couche MAC qui assure le controle d'acces a un canal partage utilise le protocole CSMA / CA, cependant, un etat de l'art sur les modeles analytiques de ce mecanisme de la norme IEEE 802.15.4 semble etre manquant.
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Festival International de Théâtre de Béjaïa. 2015, 66 pages.
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Festival International de Théâtre de Béjaïa. 2014, 48 pages.
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Festival International de Théâtre de Béjaïa, 2013, 40 pages.
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Festival International de Théâtre de Béjaïa, 2012, 65 pages.
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Ed. la maison de la culture, 2010, 10 pages.
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Gehimab Ed., 2015, 95 pages.
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Ed. Ass. GEHIMAB, 2010, 100 pages.
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Ed. Ass. GEHIMAB, 2010, 50 pages.
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Gehimab Ed., 2008, 40 pages.
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IEMed Barcelone et Gehimab Béjaïa Ed., 2007, 16 pages.
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Gehimab Ed., 2014, 90 pages. ISBN : 978-9931-9140-1-3.
http://ath-waghlis.com/documents/livreresumesahli.pdf
http://ath-waghlis.com/documents/livreresumesahli.pdf
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Gehimab Ed., 2014, 200 pages. ISBN : 978-9931-9140-1-3.
http://gehimab.org/Colloques/livreghubrini.pdf
http://gehimab.org/Colloques/livreghubrini.pdf
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Année Mondiale de l'Astronomie, Gehimab et Sirius Ed., 2009, 40 pages.
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Gehimab Ed., 2004, 50 pages.
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Ministère des Affaires Religieuses et des Awqaf Ed., 2009, 55 pages.
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Actes du Colloque International, Novembre 1997, 600 pages (à paraître aux éditions Publisud - Paris) ;