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Joint Power Allocation and Beamforming for Cooperative Networks

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International Journal of Communications, Network and System Sciences 2011年第7期4卷 447-451页

作者： Sondes Maadi noureddine Hamdi 不详

In this paper, we investigate power allocation problem with the use of transmit beamforming in a dual hop MISO (multiple input single output) relay channel. We consider either amplify and forward (AF) or decode and forward (DF) cooperative protocols at the relay and optimize the power allocated to the relay and the source, under total transmit power constraint, to minimize the bit error rate (BER) of relaying system. Cooperative communication is viewed as a method for increasing diversity gain and reducing end to end path loss. The use of relay can create a virtual antenna array so that it allows users to exploit the advantages of multiple input multiple output (MIMO) techniques. In this work, we solve cooperative ratio, which is defined as the ratio power used for cooperative transmission over the total power. This approach is then compared to an equal power assignment method and its performance enhancement is verified by simulation results.

关键词： Amplify and Forward Decode and Forward Transmit Beamforming Power Allocation MISO Cooperative Communication

Effects of Laser Hardening Process Parameters on Case Depth of 4340 Steel Cylindrical Specimen—A Statistical Analysis

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Journal of Surface Engineered Materials and Advanced Technology 2015年第3期5卷 124-135页

作者： noureddine Barka Abderrazak El Ouafi Mathematics Software and Engineering Department University of Quebec at Rimouski Rimouski Canada

Laser heat treatment is considered to be one of best-performing manufacturing processes used currently due to its flexibility and its ability to develop parts with complex geometries. In fact, this process is able to produce reliable parts with hard, thin martensite and compressive residual stresses. This paper explores the heat treatment applied to 4340 cylindrical parts heated using a Nd: Yag 3 kW laser source. In this case, the hardness profile is correlated to process parameters such as the laser source power, the beam scanning speed and the revolution speed of the part during heating. Based on preliminary tests stipulating that each parameter is varied alone within a specific range, a systematic design of final tests is performed using Taguchi matrix. The obtained results are analyzed using ANOVA method to extract the effects, the contributions and the interaction between the factors. The results are then exploited to study the sensitivity of the case depth according the variation of the process parameters. The developed model exhibits good potential for converging towards a robust model able to predict the hardness curve and to generalize it for other dimensions of cylindrical parts.

关键词： Laser Heat Treatment Cylindrical Specimen Hardness Profile Case Depth

Forensic Investigation in Communication Networks Using Incomplete Digital Evidences

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International Journal of Communications, Network and System Sciences 2009年第9期2卷 857-873页

作者： Slim REKHIS Jihene KRICHENE noureddine BOUDRIGA 不详

Security incidents targeting information systems have become more complex and sophisticated, and intruders might evade responsibility due to the lack of evidence to convict them. In this paper, we develop a system for Digital Forensic in Networking, called DigForNet, which is useful to analyze security incidents and explain the steps taken by the attackers. DigForNet combines intrusion response team knowledge with formal tools to identify the attack scenarios that have occurred and show how the system behaves for every step in the scenario. The attack scenarios construction is automated and the hypothetical concept is introduced within DigForNet to alleviate missing data related to evidences or investigator knowledge. DigForNet system supports the investigation of attack scenarios that integrate anti-investigation attacks. To exemplify the proposal, a case study is proposed.

关键词： Formal Digital Investigation Incident Response Probabilistic Cognitive Map DigForNet Anti- Forensic Attacks Investigation Attack Scenarios Reconstruction

Ab Initio Calculations of Optical Properties of TlBr and TlCl Radiation Detectors

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World Journal of Condensed Matter Physics 2011年第3期1卷 63-69页

作者： noureddine Amrane Maamar Benkraouda Fathalla Hamed 不详

We report on ab initio calculations of the optical properties of TlBr and TlCl binary semiconductor compounds using the self-consistent scalar relativistic full potential linear augmented plane wave band method (FP-LAPW) within the local density approximation (LDA) including the generalized gradient approximation (GGA). The accurate calculations of linear optical function (refractive index, reflectance, coefficient of absorption, and both imaginary and real dielectric function) is performed in the photon energy range up to 20 eV. The predicted optical constants agree well with the available experimental data.

关键词： Plane Wave Method Dielectric Function Reflectivity Refractive Index Coefficient of Absorption

Study and Design of A Medium Caliber Shell ——Multifunctional Ammunition with Shaped Charge Jet and Fragmentation Effect

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Study and Design of A Medium Caliber Shell ——Multifunction...

作者： Medjrab noureddine 南京理工大学

学位级别：硕士

为研究典型多功能战斗部作用性能,分别采用数值模拟、理论分析和实验手段研究了战斗部参数对射流形成、射流侵彻及破片形成的影响规律,给出了典型聚能装药结构射流成型结果及侵彻性能,确定了优选后的聚能装药结构参数,并开展了射流侵彻... 详细信息

为研究典型多功能战斗部作用性能,分别采用数值模拟、理论分析和实验手段研究了战斗部参数对射流形成、射流侵彻及破片形成的影响规律,给出了典型聚能装药结构射流成型结果及侵彻性能,确定了优选后的聚能装药结构参数,并开展了射流侵彻性能实验进行验证。以破甲、杀伤双功能战斗部为基础,开展了刻槽参数、热处理硬度等对破片形成结果影响规律数值模拟计算,确定了优化后的刻槽弹体参数。本文研究的主要内容如下:(1)聚能射流形成的数值模拟与理论分析聚能装药形成射流影响因素较多,如装药类型、装药结构、药型罩结构、材料及起爆方式等。本文主要从药型罩结构入手分析药型罩结构参数对射流形成的影响规律,主要选择了不同的顶角(36°,42°,48°,56°)和厚度(1.2mm、2mm)进行研究。研究工作可分为两部分:一部分工作为采是用AUTODYN(?)软件对射流的成型规律进行系统的数值模拟研究;另一部分为基于Birkhoff聚能射流成型理论分析计算了射流的成型结果计算。数值模拟和理论模型分析计算结果表明:锥角为36°、厚度为1.2mm的药性罩结构可以获得较好的射流形态。(2)聚能射流侵彻能力的数值模拟与理论分析在AUTODYN(?)中对五种不同锥角和厚度的药型罩形成射流对钢靶的侵彻性能进行数值模拟,获得了侵彻过程中射流速度、动能衰减变化规律。同时基于Birkhoff射流侵彻理论对射流侵彻深度进行计算分析,理论计算结果与数值模拟结果吻合较好。同时也对比了不同结构药型罩聚能射流的侵彻威力,结果表明锥角为36°、厚度为1.2mm的药性罩结构可以获得较好的侵彻结果。(3)聚能装药侵彻钢靶作用性能试验研究以前述仿真及数值模拟所获取的聚能装药结构为基础,开展了药型罩锥角为42°和厚度为1.2 mm的聚能装药进行了侵彻实验,得到了侵彻钢靶深度。实验结果与数值模拟结果吻合较好,证明了本文所建立的数值模拟方法及理论模型的正确性。(4)自然破片和预控破片的数值模拟研究在AUTODYN(?)中采用三维建模的方法,对采用三种不同硬度(HRC 20,32,36)壳体的自然破片和预控破片形成进行研究。通过数值模拟,对成形过程中的自然破片和预控破片质量、速度和数量进行分析。数值模拟结果与理论结果一致,表明预控破片可以提供更好的破碎性能。

关键词：聚能装药药性罩药型罩厚度射流侵彻预控破片

Effect of heat treatment on antimycotic activity of Sahara honey

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Journal of Coastal Life Medicine 2014年第11期 876-881页

作者： Moussa Ahmed Saad Aissat noureddine Djebli Pharmacognosy and Api-Phytotherapy Research Laboratory Mostaganem UniversityMostaganemAlgeria

Objective:To evaluate the influence of the temperature on honey colour,polyphenol contents and antimycotic capacity and to evaluate the correlation between these ***:Sahara honey were heated up to 25,50,75 and 100℃for 15,30 and 60 min,and their colour intensity,polyphenol contents and antimycotic *** Folin-Ciocalteu test was used to determine the total polyphenol contents(TPC).The antimycotic activity was evaluated both by agar diffusion method and micro wells dilution method against the Candida albicans(***)and Candida glabrata(***).Results:Initial values for TPC in Sahara honey ranged from 0.55 to 1.14 mg of gallic acid per kg of honey,with the average value of 0.78 mg of gallic acid per kg of *** TPC values after heat-treatment were 0.54 to 1.54 with the average value of 1.49 *** minimal inhibitory concentrations before heat-treatment of Sahara honey against *** and *** ranged from 3.06%-12.5%and 50%*** heat-treatment the minimal inhibitory concentrations between 12.5%and 50%for *** and ***,*** diameters of inhibition zones of Sahara honey with 50%concentration varied from(12.67-15.00)mm by *** to(14.33-15.67)mm by *** diameters of inhibition zones after heat-treatment at 25 and 50°C for 15.30 and 60 min ranged from(2.00-18.67)mm by *** to(8.00-16.67)mm by *** significant relations between the TPC and the colour intensity of Sahara honey(r=0.99,P<0.05).Furthermore,the results showed that the TPC and colour is not correlated with the antimycotic ***:To our knowledge this is the first report on the antimycotic capacity of Sahara honey.

关键词： Sahara honey Antimycotic capacity Heat treatment

Calibration of HVI cotton elongation measurements

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Journal of Cotton Research 2020年第4期3卷 268-277页

作者： DELHOM Christopher D. HEQUET Eric F. KELLY Brendan ABIDI noureddine MARTIN Vikki B. USDA-ARS New OrleansLA 70124USA Texas Tech University LubbockTX 79409USA Cotton Incorporated CaryNC 27513USA.

Background:The strength of cotton fiber has been extensively studied and significant improvements in fiber strength have been made,but fiber elongation has largely been ignored,despite it contributing to the energy needed to break fibers,which affects fiber handling and *** Volume Instruments(HVI)measure fiber elongation but have not been calibrated for this property,making the measurement unavailable for comparative work among *** prior work,a set of elongation calibration materials had been developed based on Stelometer results.A round trial of ten Australian and *** was conducted on six cotton samples representing a range of 4.9%to 8.1%***:By scaling the HVI elongation values of each instrument to the values of the two calibration samples,the coefficient of variation in instrument measurements was reduced from an average of 34%for the uncalibrated measurements to 5%for the calibrated *** reduction in variance allows for the direct comparison of results among instruments.A single-point elongation calibration was also assessed but found to be less effective than the proposed two-point ***:The use of an effective calibration routine on HVI measurement of cotton significantly reduces the coefficient of variation of the elongation measurement within and between *** implementation of the elongation calibration will allow testing and breeding programs to implement high-speed elongation testing which makes the use of elongation values possible in breeding programs.

关键词： Cotton Elongation High volume instrument Tenacity Work-to-rupture

Face Recognition Systems Using Relevance Weighted Two Dimensional Linear Discriminant Analysis Algorithm

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Journal of Signal and Information Processing 2012年第1期3卷 130-135页

作者： Hythem Ahmed Jedra Mohamed Zahid noureddine Laboratory of Conception and Systems Faculty of Sciences Agdal Mohammed V University Rabat Morocco.

Low-dimensional feature representation with enhanced discriminatory power of paramount importance to face recognition systems. Most of traditional linear discriminant analysis (LDA)-based methods suffer from the disadvantage that their optimality criteria are not directly related to the classification ability of the obtained feature representation. Moreover, their classification accuracy is affected by the “small sample size” (SSS) problem which is often encountered in face recognition tasks. In this paper, we propose a new technique coined Relevance-Weighted Two Dimensional Linear Discriminant Analysis (RW2DLDA). Its over comes the singularity problem implicitly, while achieving efficiency. Moreover, a weight discriminant hyper plane is used in the between class scatter matrix, and RW method is used in the within class scatter matrix to weigh the information to resolve confusable data in these classes. Experiments on two well known facial databases show the effectiveness of the proposed method. Comparisons with other LDA-based methods show that our method improves the LDA classification performance.

关键词： LDA PCA 2DLDA RW2DLDA Extraction Face Recognition Small Sample Size

Study of Frequency Effects on Hardness Profile of Spline Shaft Heat-Treated by Induction

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Journal of Materials Science and Chemical Engineering 2016年第3期4卷 1-9页

作者： Habib Hammi Abderazzak El Ouafi noureddine Barka Mathematics Computer Science and Engineering Department University of Quebec at Rimouski Rimouski Canada

This paper is devoted to the study of frequency effects on hardness profile of AISI 4340 spline shaft heat-treated by induction through an extensive 3D finite element method simulation and structured experimental investigation. Based on coupled electromagnetic and thermal fields analysis, the 3D model is used to estimate the temperature distribution and the hardness profile. The proposed study examines the hardening process parameters, such as frequency, induced current density and heating time, known to have an influence on hardened surface and builds the simulation model step by step. The established model can provide not only an accurate prediction of temperature distribution and hardness profile but also a comprehensive analysis of machine parameters effects, especially the frequency. The numerical results achieved by this model are good and present a great agreement to the experimental data.

关键词： Induction Heating Splines Shaft Hardness Profile Current Density Heating Time Frequency