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HYDRODYNAMIC AND ELASTOHYDRODYNAMIC STUDIES OF A CYLINDRICAL JOURNAL BEARING

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Journal of Hydrodynamics 2010年第2期22卷 155-163页

作者： ATTIA HILI Molka BOUAZIZ Slim MAATAR mohamed FAKHFAKH Tahar HADDAR mohamed Mechanics Modelling and Production Research Unit (U2MP)National School of Engineers of Sfax(ENIS)BP.11733038sfaxTunisia

In this article,the effect of the bearing elastic deformation on the performance characteristics of a cylindrical journal bearing is *** variety of simulation models covers hydrodynamic（HD） and elastohydrodynamic（EHD） lubrication *** Reynolds equations governing the flow in the clearance space of the journal bearing are obtained by considering the effect of mass transfer across the fluid *** finite element method with an iteration scheme was employed to solve both the Reynolds equation and the three-dimensional elasticity equation representing the displacement field in the bearing *** converged solutions for the lubricant flow and elastic deformation vector are *** characteristics of the journal bearing are computed for HD and EHD *** simulation results show that the flexibility of bearing liner has a significant influence on the performance of a cylindrical journal ***,the elastic deformations of the bearing liner extend the pressure area in the bearing and increase the minimum film ***,dynamic coefficient,load capacity and attitude angle decrease.

关键词： Reynolds equation hydrodynamic(HD) and elastohydrodynamic(EHD) lubrication theories dynamic coefficients relative eccentricity deformation coefficient

A Novel BEM for Modeling and Simulation of 3T Nonlinear Generalized Anisotropic Micropolar-Thermoelasticity Theory with Memory Dependent Derivative

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Computer Modeling in Engineering & Sciences 2021年第1期126卷 175-199页

作者： mohamed Abdelsabour Fahmy Jamoum University College Umm Al-Qura UniversityMakkahSaudi Arabia Faculty of Computers and Informatics Suez Canal University New CampusIsmailia41522Egypt

The main aim of this paper is to propose a new memory dependent derivative(MDD)theory which called threetemperature nonlinear generalized anisotropic *** system of governing equations of the problems associated with the proposed theory is extremely difficult or impossible to solve analytically due to nonlinearity,MDD diffusion,multi-variable nature,multi-stage processing and anisotropic properties of the considered ***,we propose a novel boundary element method(BEM)formulation for modeling and simulation of such *** computational performance of the proposed technique has been *** numerical results illustrate the effects of time delays and kernel functions on the nonlinear three-temperature and nonlinear displacement *** numerical results also demonstrate the validity,efficiency and accuracy of the proposed *** findings and solutions of this study contribute to the further development of industrial applications and devices typically include micropolar-thermoelastic materials.

关键词： Boundary element method memory dependent derivative three-temperature nonlinear generalized anisotropic micropolar-thermoelasticity

Linearly and Quadratically Separable Classifiers Using Adaptive Approach

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Journal of Computer Science & Technology 2011年第5期26卷 908-918页

作者： mohamed Abdel-Kawy mohamed Ali Soliman Rasha M.Abo-Bakr Department of Computer and Systems Engineering Faculty of EngineeringZagazig UniversityZagazigEgypt Departement of Mathematics Faculty of ScienceZagazig UniversityZagazigEgypt

This paper presents a fast adaptive iterative algorithm to solve linearly separable classification problems in R *** each iteration,a subset of the sampling data （n-points,where n is the number of features） is adaptively chosen and a hyperplane is constructed such that it separates the chosen n-points at a margin and best classifies the remaining *** classification problem is formulated and the details of the algorithm are ***,the algorithm is extended to solving quadratically separable classification *** basic idea is based on mapping the physical space to another larger one where the problem becomes linearly *** illustrations show that few iteration steps are sufficient for convergence when classes are linearly *** nonlinearly separable data,given a specified maximum number of iteration steps,the algorithm returns the best hyperplane that minimizes the number of misclassified points occurring through these *** with other machine learning algorithms on practical and benchmark datasets are also presented,showing the performance of the proposed algorithm.

关键词： linear classification quadratic classification iterative approach adaptive technique

Automated classification technique for edge-on galaxies based on mathematical treatment of brightness data

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Research in Astronomy and Astrophysics 2021年第10期21卷 231-238页

作者： mohamed Eassa Ibrahim mohamed Selim Walid Dabour Passent Elkafrawy Computer Science Department Integrated Thebes InstituteCairoEgypt Faculty of Computer&Artificial Intelligence Sadat City UniversitySadat CityEgypt Math and Computer Science Dept. Faculty of ScienceMenoufia UniversityEgypt Computer Science Dept. Taibah UniversityAlula BranchKingdom of Saudi Arabia School of Information Technology and Computer Science(ITCS) Nile UniversityEgypt

Classification of edge-on galaxies is important to astronomical studies due to our Milky Way galaxy being an edge-on ***-on galaxies pose a problem to classification due to their less overall brightness levels and smaller numbers of *** the current work,a novel technique for the classification of edge-on galaxies has been *** technique is based on the mathematical treatment of galaxy brightness data from their images.A special treatment for galaxies’brightness data is developed to enhance faint galaxies and eliminate adverse effects of high brightness backgrounds as well as adverse effects of background bright stars.A novel slimness weighting factor is developed to classify edge-on galaxies based on their *** technique has the capacity to be optimized for different catalogs with different brightness *** the current work,the developed technique is optimized for the EFIGI catalog and is trained using a set of 1800 galaxies from this *** classification of the full set of 4458 galaxies from the EFIGI catalog,an accuracy of 97.5% has been achieved,with an average processing time of about 0.26 seconds per galaxy on an average laptop.

关键词： techniques:image processing methods:data analysis galaxies:formation

Friction and wear of sand-contaminated lubricated sliding

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Friction 2018年第4期6卷 457-463页

作者： mohamed Ahmed RAMADAN Faculty of Engineering at Helwan Helwan University

This paper reports a test investigation of friction and wear responses from sand contaminated lubricated sliding. The influence of sand contaminants on wear and friction is characterized. Analyses are completed utilizing segments of piston ring sliding against the cylinder liner. Paraffin oil, with and without sand contaminants, is utilized. The effects of the concentration and particle size of sand are examined. Based on the observations in the present work, we found that friction and wear increase with sand concentration in the lube. Solid proposals ought to be considered, in order to enlighten the general population on the importance of changing a car engine's oil filter regularly.

关键词： sand contamination lubrication oil abrasive wear lubricated sliding

Privacy-preserved learning from non-i.i.d data in fog-assisted IoT:A federated learning approach

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Digital Communications and Networks 2024年第2期10卷 404-415页

作者： mohamed Abdel-Basset Hossam Hawash Nour Moustafa Imran Razzak mohamed Abd Elfattah Faculty of Computers and Informatics Zagazig UniversityZagazigSharqiyah44519Egypt School of Engineering and Information Technology University of New South Wales@ADFACanberraACT2600Australia Deakin University Geelong Waurn Ponds CampusAustralia Computer Science Department Misr Higher Institute for Commerce and ComputersMansoura35511Egypt

With the prevalence of the Internet of Things(IoT)systems,smart cities comprise complex networks,including sensors,actuators,appliances,and cyber *** complexity and heterogeneity of smart cities have become vulnerable to sophisticated cyber-attacks,especially privacy-related attacks such as inference and data poisoning *** Learning(FL)has been regarded as a hopeful method to enable distributed learning with privacypreserved intelligence in IoT *** though the significance of developing privacy-preserving FL has drawn as a great research interest,the current research only concentrates on FL with independent identically distributed(i.i.d)data and few studies have addressed the non-i.i.d *** is known to be vulnerable to Generative Adversarial Network(GAN)attacks,where an adversary can presume to act as a contributor participating in the training process to acquire the private data of other *** paper proposes an innovative Privacy Protection-based Federated Deep Learning(PP-FDL)framework,which accomplishes data protection against privacy-related GAN attacks,along with high classification rates from non-i.i.d ***-FDL is designed to enable fog nodes to cooperate to train the FDL model in a way that ensures contributors have no access to the data of each other,where class probabilities are protected utilizing a private identifier generated for each *** PP-FDL framework is evaluated for image classification using simple convolutional networks which are trained using MNIST and CIFAR-10 *** empirical results have revealed that PF-DFL can achieve data protection and the framework outperforms the other three state-of-the-art models with 3%–8%as accuracy improvements.

关键词： Privacy preservation Federated learning Deep learning Fog computing Smart cities

On the Gosper’s q-constant Ⅱ_q

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Acta Mathematica Sinica,English Series 2018年第11期34卷 1755-1764页

作者： mohamed EL BACHRAOUI Department Mathematical Sciences UAE University

Gosper introduced the functions sinq z and cosq z as q-analogues for the trigonometric functions sin z and cos z respectively. He stated a variety of identities involving these two q-trigonometric functions along with certain constants denoted by Πqn （n ∈ N）. Gosper noticed that all his formulas on these constants have more than two of the Πqn. So, it is natural to raise the question of establishing identities involving only two of the Πqn. In this paper, our main goal is to give examples of such formulas in only two Πqn.

关键词： q-trigonometric functions elliptic functions theta function identities

Electrochemical Noise Analysis and Electrochemical Impedance Spectroscopy for Pure Copper in Chloride Media

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Chinese Journal of Chemistry 2006年第2期24卷 247-252页

作者： NAGIUB Adham mohamed Faculty of Science Al-Azhar University Assiut 71524 Egypt

The corrosion behavior of pure copper electrode exposed to artificial seawater has been studied using electrochemical noise analysis （ENA） and electrochemical impedance spectroscopy （EIS）. A diffusion process was observed for copper exposed to chloride media as indicated by the presence of a minimum phase angle over the lowest frequency range in the impedance plots. Analysis of electrochemical noise （EN） data has been collected both in time and frequency domains. Noise resistance Rn was obtained after analyzing EN data in the time domain. A good agreement was observed between Rn values and polarization resistance Rp values obtained from EIS analysis. Localization index Ii was not found to provide information concerning corrosion mechanisms. Also skewness and kurtosis for both potential and current fluctuations did not show any mechanistic information. It was concluded that ENA could detect the corrosion rate for copper exposed to chloride media, but was not found to provide information about the corrosion mechanisms.

关键词： impedance noise analysis copper chloride media

Developing Check-Point Mechanism to Protect Mobile Agent Free-Roaming Against Untrusted Hosts

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Computers, Materials & Continua 2022年第8期72卷 3849-3862页

作者： Tarig mohamed Ahmed Department of Information Technology FCITKing Abdulaziz UniversityJeddahSaudi Arabia

Mobile Agent has many benefits over traditional distributed systems such as reducing latency,bandwidth,and *** Agent Systems are not fully utilized due to security *** paper focuses on mobile agent protection against malicious hosts.A new security mechanism called Checkpoints has been *** Mechanism(CPM)aims to protect Mobile Agent against malicious hosts in case of Capturing and Integrity *** assumes using a free-roaming mobility mechanism by Mobile agent *** main idea behind CPM is to generate multiple versions of Mobile *** multiple version is used to recover Mobile Agent from Capturing and Integrity attacks by untrusted *** versions are kept in Recovery Host(RH).RH plays a key role in CPM by controlling and monitoring MAs’recovery processes.A prototype method has been used to prove the feasibility of *** p https://***/Default-305-ARrototype was implemented by using *** framework and C#.full discussion for several scenarios has been done to analyze the feasibility and performance for *** found from this research,CPM has a strong ability to protect Mobile Agents from Capturing and Integrity attacks *** addition,there is no negative impact on the overall performance of the mobile agent system.

关键词： Mobile agent security capturing integrity attacks