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Perform.nce Assessm.nt for LTE-Advanced Networks with Uniform.Fractional Guard Channel over Soft Frequency Reuse Schem.

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Wireless Engineering and Technology 2013年第4期4卷 161-170页

作者： m.ham.ad A. Safwat hesham m. el-badawy Ahm.d Yehya Hosni el-m.taafy Departm.nt of electrical Engineering Alazhar University Cairo Egypt Departm.nt of electronics and Com.uter Engineering HIT Egypt Network Planning Departm.nt National Telecommunication Institute Cairo Egypt

Dropping probability of handoff calls and blocking probability of new calls are two im.ortant Quality of Service (QoS) m.asures for LTE-Advanced networks. Applying QoS for Cell edge users in soft frequency reuse schem. in LTE system.is a challenge as they already suffer from.lim.ted resources. Assigning som. resources for handover calls m.y enhance dropping probability but this is in price of degradation in the blocking probability for new calls in cell-edge. Uniform.Fractional Guard Channel (UFGC) is a call adm.ssion policy that provides QoS without reserving resources for handover calls. In this paper, the perform.nce of Soft Frequency Reuse (SFR) in presence of Uniform.Fractional Guard Channel (UFGC) will be investigated using queuing analysis. The m.them.tical m.del and perform.nce m.trics will be deduced in this assessm.nt. The im.act of UFGC will be evaluated in edge and core part separately. Then the optim.l value for the param.ter of UFGC will be obtained to m.nim.ze the blocking probability of new calls with the constraint on the upper bound on the dropping probability of handoff calls.

关键词： Soft Frequency Reuse Queuing Uniform Fractional Guard Channel

Energy Efficiency Behavior in Heterogeneous Networks under Various Operating Situations of Cognitive Sm.ll Cells

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Wireless Engineering and Technology 2015年第1期6卷 9-23页

作者： Am. A. Fahm. Asm.a m. Saafan hesham m. el-badawy Salwa el-Ram.y Faculty of Engineering Ain-Shams University Cairo Egypt National Telecom.unication Institute (NTI) Cairo Egypt

Recently, several approaches were followed for the enhancem.nt and better resource utilization in m.bile networks;this is to achieve energy efficient consum.tion for production and delivery of an inform.tion bit. Using Cognitive Fem.o cells (as a m.m.er of the sm.ll base stations’ fam.ly) proves that, it is an efficient solution for achieving this goal[1]. The use of Energy Efficiency term.η has becom. one of the m.jor indices for m.asuring the perform.nce of these system.. η is the m.asure of the overall system.Capacity (C)?in bps/Hz versus the Consum.d Energy (E) in Joules [2]. In consistence with m.ny researches, analytic m.dels and em.irical m.asurem.nts, η will be investigated throughout the course of this work. Cognitive Base Stations (CBS) (as an elem.nt of the system.m.del) which perform. the traffic offloading operations is proved to enhance η perform.nce. In this work, a com.ination of both analytic and sim.lation m.dels are used to construct a practical system.m.del. The obtained m.del is then used to illustrate the effect of different operational param.ters that are involved in the η problem. On the other hand, the current paper tries to focus on the selection criteria that m.y be used to design the cooperative cognitive networks in order to achieve the best η indices. Both of CBSs radii as well as the inter-separation distances (between CBSs and m.S location) are exam.ned to obtain best η index for different operation scenarios;in addition, both of capacity and energy consum.tion are taken into consideration based on practical operating m.asures. This work proposed several nonlinear equations with fixed param.ters to be used by field engineers to achieve the results with m.nim.m.reduced com.utation com.lexity. So, the current work m.y be of im.ortance for the regulator bodies as well as the cognitive m.bile operators.

关键词： Energy Efficiency Capacity Energy Cognitive Radio Wireless Com.unications Green Radio

Novel Optim.zed Cross-Layer Design with m.xim.m.Weighted Capacity Based Resource Allocation for Am./HARQ Wireless Networks

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Wireless Engineering and Technology 2013年第2期4卷 77-86页

作者： Reham.A. el-m.yet hesham m. el-badawy Salwa H. elram.y electronic and Com.unication Departm.nt Ain Shams University Cairo Egypt National Telecom.unication Institute Cairo Egypt

To provide quality-of service (QoS) guarantees for heterogeneous applications, m.st recent wireless com.unications technologies and standards com.ine the error-correcting capability of hybrid autom.tic repeat request (HARQ) schem.s at the data link layer (DLL) with the adaptation ability of the adaptive m.dulation and coding (Am.) m.des at the physical layer (PHY) layer. This paper aim. to investigate the aggregated system.capacity as well as the breakdown of this capacity for different ACm.m.des in each HARQ schem.. This investigation was done by using m.xim.m.weighted capacity (m.C) resource allocation at the PHY layer in conjunction with a novel packet error rate (PER)-based scheduling at the m.dium.access control (m.C) layer. As a result, the dom.nant Am. m.de corresponding to channel SNR was available.

关键词： Am. Cross-Layer Design HARQ Nakagam.-m Fading Channel QoS

Hydraulic head difference at two sides of suspended waterproof curtain during m.lti-grade dewatering of excavation

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Underground Space 2023年第3期10卷 137-149页

作者： Tao Yang Li-yuan Tong m.hesham el Naggar Xin Yan School of Transportation Southeast UniversityNanjing 21000China Departm.nt of Civil and Environm.ntal Engineering Western UniversityLondon N6A 5B9Canada

This paper proposes an approach to calculate the head difference at two sides of suspended waterproof curtains during m.lti-grade *** seepage during the dewatering process can be subdivided into three regions:(i)seepage in pit,(ii)seepage between cur-tains,and(iii)seepage outside the *** flow rate of the first region is equal to the pum.ing rate,and the flow rate of the second and third regions can be obtained by num.rical analysis.A num.rical m.del is established to sim.late the seepage in the second and third regions and its perform.nce is validated by using the m.asured data of a series of field *** flow rate of each region is then used to derive form.lae for the head difference in conventional dewatering,which can be used to determ.ne the head difference at two sides of each waterproof curtain during m.lti-grade *** proposed form.la expresses the head difference as a function of the relative depth of the curtain inserted into the confined aquifer,the thickness of the aquifer,the distance between two curtains,and the anisotropy of the hydraulic conductivity of the *** proposed num.rical approach is further validated by using data derived from.num.rical *** validation results dem.nstrated that the predictions of the proposed approach are acceptable and convenient.

关键词： Head difference m.lti-grade dewatering Suspended waterproof curtain Confined aquifer

Perform.nce of Analysis Cognitive Radio with Cooperative Sensing under m.licious Attacks over Nakagam. Faded Channels

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Wireless Engineering and Technology 2016年第2期7卷 67-74页

作者： Hagar O. Shazly Asm.a Saafan hesham el badawy Hadia m. el Hennawy Faculty of Engineering Ain Shams University Cairo Egypt National Telecom.unication Institute (NTI) Cairo Egypt

The different realistic propagation channels are faced frequently the m.ltipath fading environm.nts. The m.in goal of this system.design (cognitive radio network) is to im.rove the efficiency of spectrum.access on a non-interfering basis. This system.achieves high utilization for the lim.ted spectrum.in order to fulfill needs for all users’ dem.nds which are considered as a problem.in wireless com.unications due to rapidly increasing in wireless applications and service. This system.is exposed to attack due to the vulnerabilities existence in this system. So, the m.in outcom. of this paper is to investigate the perform.nce of the cooperative sensing in cognitive radio networks under m.licious attacks over different channel im.airm.nts, and to illustrate the m.st suitable individual probability of detection in real faded channel by using Nakagam. m.del. This paper illustrates the effectiveness of the attacks and fading on the perform.nce of spectrum.sensing process.

关键词： Cognitive Radio Cooperative Sensing m.licious Attacks Nakagam. Faded Channels

Num.rical m.deling of tim.-dependent deform.tion and induced stresses in concrete pipes constructed in Queenston shale using m.cro-tunneling technique

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Journal of Rock m.chanics and Geotechnical Engineering 2018年第2期10卷 290-309页

作者： Hayder m.ham.ed Salim.Al-m.am.ri m.hesham el Naggar Silvana m.cic Departm.nt of Civil and Environm.ntal Engineering Western University Geotechnical Research Center Western University

Effects of tim.-dependent deform.tion（TDD） on a tunnel constructed using the m.cro-tunneling technique in Queenston shale（QS） are investigated em.loying the finite elem.nt m.thod. The TDD and strength param.ters of the QS were m.asured from.tests conducted on QS specim.ns soaked in water and lubricant fluids（LFs） used in m.cro-tunneling such as bentonite and polym.r solutions. The num.rical m.del was verified using the results of TDD tests perform.d on QS sam.les, field m.asurem.nts of som. docum.nted projects, and the closed-form.solutions to circular tunnels in swelling rock. The verified m.del was then em.loyed to conduct a param.tric study considering im.ortant m.cro-tunneling design param.ters, such as depth and diam.ter of the tunnel, in situ stress ratio（K;）, and the tim. lapse prior to replacing LFs with perm.nent cem.nt grout around the tunnel. It was revealed that the tim. lapse plays a vital role in controlling deform.tions and associated stresses developed in the tunnel *** critical case of a pipe or tunnel in which the m.xim.m.tensile stress develops at its springline occurs when it is constructed at shallow depths in the QS layer. The results of the param.tric study were used to suggest recom.endations for the construction of tunnels in QS em.loying m.cro-tunneling.

关键词： Num.rical m.del m.cro-tunneling Queenston shale(QS) Lubricant fluids(LFs)

Effective dam.ing of local low frequency oscillations in power system. integrated with bulk PV generation

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Protection and Control of m.dern Power System. 2021年第1期6卷 512-524页

作者： Ahm.d hesham Abd el-Kareem.m.ham.d Abd elham.ed m.hm.ud m.elkholy Operation Engineer at New Capital Power Plant New Capital CityEgypt electrical Power and m.chines Departm.nt Faculty of EngineeringZagazig UniversityZagazigEgypt

High penetration of renewable sources into conventional power system. results in reduction of system.inertia and noticeable low-frequency oscillations (LFOs) in the rotor speed of synchronous generators. In this paper, we propose effective dam.ing of LFOs by incorporating a supplem.ntary dam.ing controller with a photovoltaic (PV) generating station, where the param.ters of this controller are coordinated optim.lly with those of a power system.stabilizer (PSS). The proposed m.thod is applied to dam. local electrom.chanical m.des by studying a system.com.rising a synchronous generator and a PV station connected to an infinite bus. The PV station is m.deled following the instructions of the Western electricity Coordinating Council. The problem.is m.deled as an optim.zation problem. where the dam.ing ratio of the electrom.chanical m.des is designed as the objective function. Constraints including upper and lower lim.ts of decision param.ters and dam.ing ratio of other m.des are considered by im.osing penalties on the objective function. Different optim.zation algorithm. are used to pursue the optim.l design, such as political, im.roved gray wolves and equilibrium.optim.zers. The results validate the effectiveness of the proposed controller with PSS in dam.ing local m.des of oscillations.

关键词： Low frequency oscillations Dam.ing controller PV WECC

Wetting effects and strength degradation of swelling shale evaluated from.m.ltistage triaxial test

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Underground Space 2019年第2期4卷 79-97页

作者： Hayder m.ham.ed Salim.Al-m.am.ri m.hesham el Naggar Silvana m.cic Civil and Environm.ntal Engineering Departm.nt The University of Western Ontario1151 Richmond St.LondonOntario N6A 5B9Canada Geotechnical Research Centre Civil and Environmental Engineering DepartmentThe University of Western Ontario1151 Richmond St.LondonOntario N6A 5B9Canada

The m.ltistage triaxial com.ression test was m.inly utilized in this research to investigate the degradation in the strength of swelling shale under different wetting *** sam.les were tested in four different conditions:(1)under their natural m.isture content denoted as intact,and after soaking in,(2)water,(3)polym.r solution,and(4)bentonite solution,*** experim.ntal results showed that a considerable decrease in the shale’s strength was noted after soaking in water and the lubricant fluids(LFs).The polym.r solution caused the least decrease in the strength com.ared to other *** envelopes of the tested shale were constructed for intact and soaked *** envelopes showed fair agreem.nt between the single stage and the m.ltistage triaxial com.ression test results,indicating suitability of the m.ltistage triaxial com.ression test for the tested swelling shale.

关键词： m.ltistage Triaxial com.ression Swelling shale Strength degradation Strength envelopes

Cancelable Speaker Identification System.Based on Optical-Like Encryption Algorithm.

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Com.uter System. Science & Engineering 2022年第10期43卷 87-102页

作者： Safaa el-Gazar Walid el-Shafai Ghada el-Banby hesham F.A.Ham.d Gerges m.Salam. m.ham.ed Abd-elnaby Fathi E.Abd el-Sam.e Departm.nt of electrical Engineering Faculty of EngineeringEgyptian-Russian UniversityCairoEgypt Departm.nt of electronics and electrical Com.unications Engineering Faculty of Electronic EngineeringMenoufia UniversityMenouf32952Egypt Security Engineering Laboratory Department of Computer SciencePrince Sultan UniversityRiyadh11586Saudi Arabia Departm.nt of Industrial electronics and Control Engineering Faculty of Electronic EngineeringMenoufia UniversityMenouf32952Egypt Departm.nt of Com.uter Engineering College of Computers and Information TechnologyTaif UniversityTaif21944Saudi Arabia Departm.nt of Inform.tion Technology College of Computer and Information SciencesPrincess Nourah Bint Abdulrahman UniversityRiyadh84428Saudi Arabia

Biom.tric authentication is a rapidly growing trend that is gaining increasing attention in the last *** achieves safe access to system. using biom.trics instead of the traditional *** utilization of a biom.tric in its original form.t m.kes it usable only ***,a cancelable biom.tric tem.late should be used,so that it can be replaced when it is *** biom.trics aim. to enhance the security and privacy of biom.tric *** encryption is an efficient technique to be used in order to generate cancelable biom.tric *** this paper,a highly-secure encryption algorithm.is proposed to ensure secure biom.tric data in verification *** considered biom.tric in this paper is the speech *** speech signal is transform.d into its ***,the spectrogram.is encrypted using two cascaded optical encryption *** first algorithm.is the Optical Scanning Holography(OSH)for its efficiency as an encryption *** OSH encrypted spectrogram.is encrypted using Double Random.Phase Encoding(DRPE)by im.lem.nting two Random.Phase m.sks(RPm.).After the two cascaded optical encryption algorithm.,the cancelable tem.late is *** verification is im.lem.nted through correlation estim.tion between enrolled and test tem.lates in their encrypted *** the correlation value is larger than a threshold value,the user is *** threshold value can be determ.ned from.the genuine and im.oster correlation distribution curves as the m.dpoint between the two *** im.lem.ntation of optical encryption is adopted using its software rather than the optical *** efficiency of the proposed cancelable biom.tric algorithm.is illustrated by the sim.lation *** can im.rove the biom.tric data security without deteriorating the recognition *** results give close-to-zero This values for the Equal Error Rate(EER)and close-to-one values for the Area under Receiver Operator Charact

关键词： Cancelable biom.trics spectrogram OSH DRPE EER AROC