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Journal of Coastal Life Medicine 2015年第2期 106-108页

作者： hichem kacem Lassad Neifar Laboratory of Biodiversity and Aquatic Ecosystems Department of Life SciencesFaculty of Sciences of SfaxUniversity of SfaxPC 11713000 SfaxTunisia

Objective:To investigate the parasitic inventory of Balistes capriscus(Teleostei:Balistidae)(***)from the Gulf of Gabès(Southern Tunisia,Central Mediterranean Sea).Methods:A parasitological survey of the grey triggerfish ***(Gmelin,1788)from the Gulf of Gabès(Southern Tunisia,Central Mediterranean Sea)was conducted monthly from May 2007 to April 2009.A total of 480 fishes were collected from commercial catches by pelagic trawl net at different fishing ports at Chebba(34°14'N,11°06'E),Kerkennah(34°45'N,11°17'E)and Zarzis(33°41'N,11°48'E).The weight,the size,the sex,the date and the area of capture of each specimen were *** were then examined to search for ectoparasites and *** each parasite species,parasitological indices were ***:Five species of parasites were identified,among which a new species of Digenea Hypocreadium caputvadum was discovered and two species of parasites were reported for the first time in the ***:It is the first inventory of the ecto and endoparasites of grey triggerfish collected from the Gulf of Gabès Mediterranean Sea.

关键词： Parasitic inventory Balistes capriscus Gulf of Gabès Mediterranean Sea

Gonadal maturation and histological observations of the grey triggerfish Balistes capriscus Gmelin,1789(Teleostei:Balistidae)in the Gulf of Gabès,Tunisia

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Journal of Coastal Life Medicine 2015年第5期 341-347页

作者： hichem kacem Lobna boudaya Lassad Neifar Laboratory of Biodiversity and Aquatic Ecosystems Department of Life SciencesFaculty of Sciences of SfaxUniversity of SfaxPC 11713000 SfaxTunisia

Objective:To determine the spawning activity using gonadosomatic index(GSI)and gonad histology the Balistes capriscus(Teleostei:Balistidae)of the Gulf of Gabès(Southern Tunisia,Central Mediterranean Sea).Methods:The reproductive biology of the species,based on 756(480 females and 276 males),collected from commercial catches at several fishing ports including Chebba,Kerkennah and Zarzis at respective GPS coordinates(34°14'N,11°06'E),(34°45'N,11°17'E),(33°41'N,11°48'E)was studied over 28 months(January 2008-April 2010)using GSI and gonad *** used in this study ranged from 11.30 to 45.60 cm in fork ***:Both GSI and gonad histology suggest that spawning activity occurred mainly between July and mid-September with a peak in July,coinciding with summer *** first maturation occurred at 20.26 cm fork length for females and 21.30 cm fork length for *** monthly values of hepatosomatic index and condition factor(K)indicated that the liver is the main organ responsible for the mobilization process of the energizing reserves during the sexual ***:It is the first inventory of gonadal maturation and histological observations of the grey triggerfish Balistes capriscus Gmelin,1789(Teleostei:Balistidae)in the Gulf of Gabès,(Southern Tunisia,Central Mediterranean Sea).

关键词： Gonad histology Gonadosomatic index Sexual maturation Balistidae Spawning seasonality

Influence of season,size and sex on the dynamic of gill metazoan parasite infesting the Balistes capriscus(Teleostei:Balistidae)of the Gulf of Gabès(Tunisia)

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Journal of Coastal Life Medicine 2015年第4期 284-289页

作者： hichem kacem Lobna boudaya Lassad Neifar Laboratory of Biodiversity and Aquatic Ecosystems Department of Life SciencesFaculty of Sciences of SfaxUniversity of SfaxPC 11713000 SfaxTunisia

Objective:To investigate the effects of season,size and sex on the dynamic of gill metazoan parasite infesting the Balistes capriscus(Gmelin,1788)(Teleostei:Balistidae)(***)of the Gulf of Gabès(Southern Tunisia,Central Mediterranean Sea).Methods:A parasitological survey of the grey triggerfish *** from the Gulf of Gabès(Southern Tunisia,Central Mediterranean Sea)was conducted monthly from June 2011 to June 2012.A total of 1080 fish were collected from commercial catches by pelagic trawl net at different fishing ports at Chebba(34°14'N,11°06'E),Kerkennah(34°45'N,11°17'E)and Zarzis(33°41'N,11°48'E).The weight,size,sex,date and area of capture of each specimen were ***,*** was examined to search for *** each parasite species,parasitological indices were ***:The parasite species are indentified as two copepods:Naobranchia variabilis,Taneacanthus ballistae and a monogenean:Ancyrocephalus *** parasitological indices depend significantly on seasonality;the highest prevalence of Naobranchia variabilis,Taneacanthus ballistae and Ancyrocephalus balisticus(28.89%,35.93%and 55.56%respectively)was recorded during summer season(June–August),while the lowest prevalence of each(6.3%,4.44%,8.15%)recorded during winter season(December–February).Furthermore the parasitological indices depend significantly on the host size but not on host ***:Our data suggest that the dynamic of gill metazoan parasite infesting *** is a result of a complex of biotic and abiotic *** is the first study on the effects of season,size and sex on the dynamic of gill metazoan parasite infesting ***(Teleostei:Balistidae)of the Gulf of Gabès(Southern Tunisia,Central Mediterranean Sea).

关键词： Dynamic Gill metazoan parasite Balistes capriscus Gulf of Gabès

Performance of Free Space Optical Communication System Based on M-ary PPM Modulation over Double Generalized Gamma Channel

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China Communications 2020年第4期17卷 19-30页

作者： Mohamed Maalej hichem Besbes Higher School of Communications of Tunis University of Carthage2083 El Ghazala ArianaTunisia

In this paper, we provide analytical results on average Symbol Error Probability(SEP) of a Free Space Optics(FSO) link employing M-ary Pulse Position Modulation(PPM), subjected to turbulent atmosphere modeled with Double Generalized Gamma(DGG) distribution. FSO link is generally impaired by turbulent atmosphere and pointing errors. As far as we know, results are presented in previous works by considering the atmosphere turbulence modeled with a Gamma-Gamma distribution. In our work, we also give asymptotic results on average SEP in order to approximate its evolution at high Signal-to-Noise-Ratio(SNR). Numerical results showed that FSO link performance is enhanced when PPM-modulation index is increased, for both strong and moderate turbulence regimes, and for both strong and weak pointing error jitter. Monte-Carlo simulations were presented to corroborate our analytical expressions.

关键词： FSO DGG atmospheric turbulence PPM modulation SEP pointing error

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The Obstacle Problem For Nonlinear Degenerate Elliptic Equations with Variable Exponents and L^(1)-Data

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Journal of Partial Differential Equations 2022年第2期35卷 101-122页

作者： KHELIFI hichem Department of Mathematics University of AlgiersAlgeria.2 Street Didouche Mourad Algiers.Laboratory LEDPNLHMENS-KoubaAlgeria

The aim of this paper is to study the obstacle problem associated with an elliptic operator having degenerate coercivity,and L^(1)-*** functional setting involves Lebesgue-Sobolev spaces with variable *** prove the existence of an entropy solution and show its continuous dependence on the L^(1)-data in W^(1.q(-))(Ω)with some q(.)>1.

关键词： Ostacle problem Degenerate Coercivity Variable exponents L^(1)data Truncation function

Three-Dimensional Modeling of the Retinal Vascular Tree via Fractal Interpolation

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Computer Modeling in Engineering & Sciences 2021年第4期127卷 59-77页

作者： hichem Guedri Abdullah Bajahzar Hafedh Belmabrouk Electronics and Microelectronics Laboratory Department of PhysicsFaculty of SciencesMonastir UniversityMonastir5019Tunisia Department of Computer Science and Information College of ScienceMajmaah UniversityZulfi11932Saudi Arabia Department of Physics College of Science ZulfiMajmaah UniversityZulfi11932Saudi Arabia

In recent years,the three dimensional reconstruction of vascular structures in the field of medical research has been extensively *** studies describe the various numerical methods to numerical modeling of vascular structures in ***,the current approaches remain too expensive in terms of storage ***,it is necessary to find the right balance between the relevance of information and storage *** article adopts two sets of human retinal blood vessel data in 3D to proceed with data reduction in the first part and then via 3D fractal reconstruction,recreate them in a second *** results show that the reduction rate obtained is between 66%and 95%as a function of the tolerance *** on the number of iterations used,the 3D blood vessel model is successful at reconstruction with an average error of 0.19 to 5.73 percent between the original picture and the reconstructed image.

关键词： Fractal interpolation 3D Douglas–Peucker algorithm 3D skeleton blood vessel tree iterated function system retinal image

ON A BI-HARMONIC EQUATION INVOLVING CRITICAL EXPONENT: EXISTENCE AND MULTIPLICITY RESULTS

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Acta Mathematica Scientia 2011年第4期31卷 1213-1244页

作者： Zakaria Boucheche Ridha Yacoub hichem Chtioui Institut Prparatoire aux Etudes d'Ingenieur de Monastir Avenue Ibn Al Jazzar 5019 Monastir Tunisia Dpartement de Mathmatiques Facult des Sciences de Sfax Route Soukra Sfax Tunisia

In this paper, we consider the problem of existence as well as multiplicity results for a bi-harmonic equation under the Navier boundary conditions： △2 u = K（x）u p , u 〉 0 in Ω , △u = u = 0 on Ω , where Ω is a smooth domain in R n , n 5, and p ＋ 1 = 2 n n 4 is the critical Sobolev exponent. We obtain highlightly a new criterion of existence, which provides existence results for a dense subset of positive functions, and generalizes Bahri-Coron type criterion in dimension six. Our argument gives also estimates on the Morse index of the obtained solutions and extends some known results. Moreover, it provides, for generic K, Morse inequalities at infinity, which delivers lower bounds for the number of solutions. As further applications of this Morse theoretical approach, we prove more existence results.

关键词： critical points at infinity Palais-Smale condition Morse lemma at infinity Morse inequalities

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The Impact of the Superposition Coding Concept on Admission Control Strategy in OFDMA-Based Network

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China Communications 2018年第6期15卷 68-83页

作者： Yosra Abbes Sameh Najeh hichem Besbes Research Laboratory COSIM Sup'Com University of Carthage

Admission control is a key mechanism to manage the increasing number of the simultaneous demanding services, requiring a desired Quality of Service(QoS) in a spectrum efficient manner. To address this issue,we investigate in this work, the use of the superposition coding technique to increase the system capacity through multiuser diversity exploitation. We propose a novel joint admission control and superposition coding formalism based on different utility functions:Opportunistic(OPSC), Great Fairness(GFSC)and Proportional Fairness(PFSC). Simulation results show the superiority of our proposed approaches over other by providing higher mean of served VoIP users and higher throughput while maintaining an average VoIP packet transmission delay lower than 0.6 ms.

关键词： admission control QoS superposition coding opportunistic great fairness proportional fairness VoIP users

COURSE TIMETABLING AT A TUNISIAN UNIVERSITY:A CASE STUDY

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Journal of Systems Science and Systems Engineering 2008年第3期17卷 334-352页

作者： Abdelaziz DAMMAK Abdelkarim ELLOUMI hichem KAMOUN Jacques A.FERLAND Department of Applied Quantitative Methods GIAD Laboratory University of SfaxFSEGTunisia Department of Applied Quantitative Methods GlAD Laboratory University of SfaxFSEGTunisia Département d'Informatique et de Recherche Opérationnelle Universitéde Montréal QuébecCanada

This paper deals with the Course Timetabling Problem at an institution in a Tunisian University. We introduce a heuristic procedure to construct a feasible timetable for all lectures and tutorials taken by different groups of each sub-section of any section. We describe the timetabling problem using a list of all specific hard and soft constraints. We formulate the problem as a set of linear constraints using two sets of binary variables corresponding to lectures and tutorials, respectively. This heuristic is illustrated with real data for a sub-section of the Faculty of Economics and Management Sciences of Sfax in Tunisia, and the resulting timetables are compared with those generated manually. The results of another full section have confirmed the good quality of the proposed heuristic when compared with the hand made solution.

关键词： Educational timetabling integer programming implementations heuristic search

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A sliding-neural network control of induction-motor-pump supplied by photovoltaic generator

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Protection and Control of Modern Power Systems 2019年第1期4卷 332-348页

作者： hichem Hamdi Chiheb Ben Regaya Abderrahmen Zaafouri University of Tunis Higher National Engineering School Of Tunis(ENSIT)Engineering Laboratory of Industrial Systems and Renewable Energies(LISIER)5 avenue Taha HusseinPO Box 561008TunisTunisia

Energy production from renewable sources offers an efficient alternative non-polluting and sustainable solution. Among renewable energies, solar energy represents the most important source, the most efficient and the least expensive compared to other renewable sources. Electric power generation systems from the sun’s energy typically characterized by their low efficiency. However, it is known that photovoltaic pumping systems are the most economical solution especially in rural areas. This work deals with the modeling and the vector control of a solar photovoltaic (PV) pumping system. The main objective of this study is to improve optimization techniques that maximize the overall efficiency of the pumping system. In order to optimize their energy efficiency whatever, the weather conditions, we inserted between the inverter and the photovoltaic generator (GPV) a maximum power point adapter known as Maximum Power Point Tracking (MPPT). Among the various MPPT techniques presented in the literature, we adopted the adaptive neuro-fuzzy controller (ANFIS). In addition, the performance of the sliding vector control associated with the neural network was developed and evaluated. Finally, simulation work under Matlab / Simulink was achieved to examine the performance of a photovoltaic conversion chain intended for pumping and to verify the effectiveness of the speed control under various instructions applied to the system. According to the study, we have done on the improvement of sliding mode control with neural network. Note that the sliding-neuron control provides better results compared to other techniques in terms of improved chattering phenomenon and less deviation from its reference.

关键词： Maximum power point tracking(MPPT) Adaptive Neuro-fuzzy inference systems(ANFIS) Photovoltaic(PV)systems Fuzzy logic controller(FLC) Pump Sliding mode controller