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Search Results: 1 - 10 of 158 matches for " Aymen Kamoun "
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OFDM Transmission Performance Evaluation in V2X Communication
Aymen Sassi,Faiza Charfi,Yassin El Hillali,Lotfi Kamoun
International Journal of Computer Science Issues , 2012,
Abstract: The Vehicle to Vehicle and Vehicle to Infrastructure V2X communication systems are one of the main topics in research domain. Its performance evaluation is an important step before their on boards integration into vehicles and its probable real deployment. Being the first of a series of three publications, this paper studies the physical layer PHY of the upcoming vehicular communication standard IEEE 802.11p. An IEEE.802.11p PHY model, with much associated phenomena, is implemented in Vehicle to Vehicle V2V and Vehicle to Roadside unit V2I, situations through different scenarios. The series of simulation results carried out, perform data exchange between high-speed vehicles over different channels models and different transmitted packet size. We underline several propagation channel and other important parameters which affect both the physical layer network performance and the quality of transmission QoT. The Bit Error Rate BER versus Signal to Noise Ratio SNR of all coding rates is used to evaluate the performance of the communication.
Ontology-based collaborative framework for disaster recovery scenarios
Sakkaravarthi Ramanathan,Aymen Kamoun,Khalil Drira,Christophe Chassot
Computer Science , 2012,
Abstract: This paper aims at designing of adaptive framework for supporting collaborative work of different actors in public safety and disaster recovery missions. In such scenarios, firemen and robots interact to each other to reach a common goal; firemen team is equipped with smart devices and robots team is supplied with communication technologies, and should carry on specific tasks. Here, reliable connection is mandatory to ensure the interaction between actors. But wireless access network and communication resources are vulnerable in the event of a sudden unexpected change in the environment. Also, the continuous change in the mission requirements such as inclusion/exclusion of new actor, changing the actor's priority and the limitations of smart devices need to be monitored. To perform dynamically in such case, the presented framework is based on a generic multi-level modeling approach that ensures adaptation handled by semantic modeling. Automated self-configuration is driven by rule-based reconfiguration policies through ontology.
OFDM Transmission Performance Evaluation in V2X Communication
Aymen Sassi,Faiza Charfi,Lotfi Kamoun,Yassin Elhillali,Atika Rivenq
Computer Science , 2014,
Abstract: The Vehicle to Vehicle and Vehicle to Infrastructure V2X communication systems are one of the main topics in research domain. Its performance evaluation is an important step before their on board integration into vehicles and its probable real deployment. This paper studies the physical layer PHY of the upcoming vehicular communication standard IEEE 802.11p. This standard PHY Layer model, with much associated phenomena, is implemented in V2V and V2I, situations through different scenarios. The series of simulation results carried out, perform data exchange between high speed vehicles over different channels models and different transmitted packet size. We underline several propagation channel and other important parameters, which affect both the physical layer network performance and the QoT. The Bit Error Rate BER versus Signal to Noise Ratio SNR of all coding rates is used to evaluate the performance of the communication.
A Symbol-Based Estimation Technique for Inter-vehicular Communication Performance Optimization
Aymen Sassi,Faiza Charfi,Lotfi Kamoun,Yassin Elhillali,Atika Rivenq
Computer Science , 2014,
Abstract: The aim of this paper is to enhance the quality of Orthogonal Frequency Division Multiplexing OFDM estimation in dedicated vehicular communication transmission V2X networks. Wireless Access in Vehicular Environment WAVE as also known IEEE 802.11p represents the standard for these networks. Developing a reliable inter-vehicular V2X communication has to focus on optimizing its real performances. In this work, we studied the fact that WAVE transmission uses the channel characteristics designed for indoor and stationary communication terminals in IEEE 802.11a. In this paper, we propose an approach to overcome this mobility problem of terminal communication. The considered solution consists in using pilot estimation technique to reduce the high bit error rate. First, we highlight the impact of rearranging the pilot symbol positions on the quality of transmission QoT. Second, we try to overcome one of the PHY layer estimation constraints by adding two new pilot symbols. By considering pilot symbol aided channel estimation at the transmitter, we focus on Least Square LS and Minimum Mean Square Error MMSE channel estimation on the receiver. A range of simulations is carried out according to ratio between the Bit Error Rate BER and the Signal to Noise Ratio SNR. We demonstrate that rearranging pilot pattern can offer better results than standardized ones. Furthermore, we prove that adding pilots symbols can provide the best performances.
Performance Analysis of Two Priority Queuing Systems in Tandem  [PDF]
Faouzi Kamoun
American Journal of Operations Research (AJOR) , 2012, DOI: 10.4236/ajor.2012.24060
Abstract: In this paper, we consider a tandem of two head-of-line (HOL) non-preemptive priority queuing systems, each with a single server and a deterministic service-time. Two classes of traffic are considered, namely high priority and low priority traffic. By means of a generating function approach, we present a technique to derive closed-form expressions for the mean buffer occupancy at each node and mean delay. Finally, we illustrate our solution technique with some numerical examples, whereby we illustrate the starvation impact of the HOL priority scheduling discipline on the performance of the low-priority traffic stream. Our research highlights the important fact that the unfairness of the HOL priority scheduling becomes even more noticeable at the network level. Thus this priority mechanism should be used with caution.
Compared Efficiency of Abilities to Steer Learning Situations by Two Categories of Sport and Physical Education Teachers Having Different Levels of Academic Qualification  [PDF]
Maher Mrayeh, Aymen Hawani, Aymen Mechrgui
Advances in Physical Education (APE) , 2014, DOI: 10.4236/ape.2014.43019
Abstract: The aims of this study is to make an obvious fact about the impact of academic qualification of sport teachers on degree of abilities to steer learning situations. 20 teachers working in 6 scholar establishments and having a professional experience between 7 and 10 years were participated in this study. They are divided according to the level of their academic qualification. The experimental task is to make video and sound recordings of teachers sessions provided by all chosen pedagogical frameworks. The evaluation will focus on different indicators of professional skill of driving situations teachings. In total, 40 sessions randomly selected were filmed. The results obtained allowed us to infer that the piloting skill teaching situations is moderately mastered by all teachers observed regardless of their level of academic qualification. However, it should be mentioned that there is a little difference in favor of teachers ma?trisards. It should also be noted that difficulties were identified in two categories of teachers observed (master and master’s degree). Difficulties in indicators related to the explanation of the task to be performed and the level of precision of resources to which students have access to perform learning. Nevertheless, it should be noted that teachers controlled more or less the organization of groups and compliance planning. Finally, this study showd that masters teachers are more skilled at the precision of resources, group organization and encouragement of students. However, the explanation of the task to be performed and the respect of planning are indifferent to the variable level of qualification.


Role of Platelet Rich Plasma in Treatment of Diabetic Foot Ulcers  [PDF]
Aymen Salem, Ahmad M. Tawfik
Surgical Science (SS) , 2016, DOI: 10.4236/ss.2016.76038
Abstract: Objectives: The aim of this study is to compare between the platelet rich plasma and balanced moist dressing as regards the healing rate in chronic non ischemic diabetic foot ulcers. Patients and Method: From Feb. 2014 till May 2015, 73 patients from the attendees to Zagazig university hospitals were selected to our study. 2 groups were created, one for PRP (platelet rich plasma) and the other for balanced moist dressing. Frequent registration for the number of healed ulcers was done every week. Results: By the end of the 3rd week almost all the ulcers in the PRP group were healed. But the other group needed about 8th weeks for the same results. Conclusion: PRP seems to be an attractive choice in management of chronic diabetic ulcers provided that there is good blood supply and proper offloading was done.
Factors determining operating cash flow: case of the Tunisian commercial companies
Aymen Telmoudi
International Journal of Business and Management , 2010, DOI: 10.5539/ijbm.v5n5p188
Abstract: In this article, we studied the problem of the determination of operating cash flows. On the basis of a sample representative of the Tunisian commercial companies, we determined the explanatory power of the operating cycle components on the behaviour of the operating cash-flows. The results of this study prove that our dependent variable, operating cash-flow, is significantly given by the means of four factors dependent on the operating cycle: the timely debt collection, the timely debt payment, the timely flow of stock and the gross commercial margin. However, our dependent variable varies independently of two factors: Earnings and Variation of turnover.
Local monomialization conjecture of a singular foliation of Darboux type
Aymen Braghtha
Mathematics , 2015,
Abstract: After the nice result introduced by Belotto in [1] concerning the local monomialization of a singular foliation given by n first integrals, this work is a continuation in the same spirit. In this paper, we introduce a important conjecture about local monomialization of a singular foliation of Darboux type (see section 1). This conjecture can be used to study pseudo-abelian integrals [2,4].
Blowing-up of locally monomially foliated space
Aymen Braghtha
Mathematics , 2015,
Abstract: In this paper, we prove that the blowing-up preserve the local monomiality of foliated space.
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