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Search Results: 1 - 10 of 401584 matches for " Amr M. Kishk "
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Enhancements in the Security Level for Wireless Sensor Network  [PDF]
Amr M. Kishk, Nagy W. Messiha, Nawal A. El-Fishawy, Abd-Elrahman A. Alkafs, Ahmed H. Madian
Journal of Information Security (JIS) , 2015, DOI: 10.4236/jis.2015.63022
Abstract: The trade off between the energy consumption and the quality of the received image should be considered as a main point in the techniques design in Wireless Sensor Network (WSN). This paper analyzes the performance of multiple image encryption algorithms with different approaches. And also, it introduces two proposed modulation techniques to enhance the performance of WSN. These two techniques merge both the image and the audio in one signal. The merging process enhances the energy consumption data rate. In addition, it removes the effectiveness of the jamming completely from both the reconstructed image and reconstructed audio signal at the receiver. So, the receiver will reconstruct the image without jamming effectiveness. The paper introduces a proposed audio encryption algorithm. The use of encryption algorithms for both image and audio signals with the merging process enhances the security level. Popular metrics are used to compare between these image encryption algorithms and also to show the benefits from these enhancements. The results show the preference of one of these image encryption algorithms to others. And also, the merging process enhances the bit rate to high level.
A Symmetry-Based Formalism for the Electrodynamics of Nanotubes
Said M. Mikki;Ahmed A. Kishk
PIER , 2008, DOI: 10.2528/PIER08081704
Abstract: In this paper, a general symmetry-based approach to the electrodynamics of a class of low-dimensional structures, carbon nanotubes, is proposed. The contribution of the microscopic configuration is handled using the symmetry group of the structure under consideration. An explicit form of the electromagnetic field is derived starting from a general nonlocal linear susceptibility model expressed as a low-dimensional phenomenological response function. The general form of the field obtained is used to devise new theoretical insights by providing a framework for the computation of the nanotube Green's functions.
Physical Theory for Particle Swarm Optimization
Said M. Mikki;Ahmed A. Kishk
PIER , 2007, DOI: 10.2528/PIER07051502
Abstract: We propose an inter-disciplinary approach to particle swarm optimization (PSO) by establishing a molecular dynamics (MD) formulation of the algorithm, leading to a physical theory for the swarm environment. The physical theory provides new insights on the operational mechanism of the PSO method. In particular, a thermodynamic analysis, which is based on the MD formulation, is introduced to provide deeper understanding of the convergence behavior of the basic classical PSO algorithm. The thermodynamic theory is used to propose a new acceleration technique for the PSO. This technique is applied to the problem of synthesis of linear array antennas and very good improvement in the convergence performance is observed. A macroscopic study of the PSO is conducted by formulating a diffusion model for the swarm environment. The Einstein's diffusion equation is solved for the corresponding probability density function (pdf) of the particles trajectory. The diffusion model for the classical PSO is used, in conjunction with Schr¨odinger's equation for the quantum PSO, to propose a generalized version of the PSO algorithm based on the theory of Markov chains. This unifies the two versions of the PSO, classical and quantum, by eliminating the velocity and introducing position-only update equations based on the probability law of the method.
Electromagnetic Scattering by Multi-Wall Carbon Nanotubes
Said M. Mikki;Ahmed A. Kishk
PIER B , 2009, DOI: 10.2528/PIERB09040605
Abstract: We provide here a theoretical description of electromagnetic scattering by multi-wall carbon nanotubes based on an effective-boundary condition derived previously using a phenomenological quantum model. We present the basic analytical solution, extending it then to include the electromangetic interaction between multiple concentric tubes in the general multi-wall carbon nanotube case.
Electromagnetic Wave Propagation in Nonlocal Media: Negative Group Velocity and Beyond
Said M. Mikki;Ahmed A. Kishk
PIER B , 2009, DOI: 10.2528/PIERB09031911
Abstract: We study theoretically the propagation of electromagnetic waves in an infinite and homogenous medium with both temporal and spatial dispersion included. We derive a partial differential equation connecting temporal and spatial dispersion to achieve negative group velocity. Exact solutions of the equation are found and shown to lead to the possibility of exciting constant negative group velocity waves. We then investigate the effect of spatial dispersion on the power flow and derive the first-, second-, and third-order corrections of power flow due to the nonlocality in the medium. This derivation suggests a path beyond the group velocity concept.
Derivation of the Carbon Nanotube Susceptibility Tensor Using Lattice Dynamics Formalism
Said M. Mikki;Ahmed A. Kishk
PIER B , 2008, DOI: 10.2528/PIERB08082301
Abstract: We develop in this paper a theoretical approach to describe the electrodynamics of carbon nanotubes (CNTs). A lattice dynamics formalism is employed to model the mechanical response of matter to the radiation field. We start first by deriving the normal modes of the free lattice. Then, a simple and general microscopic model for light-matter interaction is proposed and the resulting mechanical equation of motion is derived using a suitable Lagrangian formalism. The symmetry group of the CNT is employed to explicitly probe the nonlocal structure of the fields and to carefully insure that higher-order Floquet modes are included in the derivation. The normal modes are then employed to perform an eigenmode expansion for the solution of the mechanical equation of motion, leading to the susceptibility tensor of the CNT medium. The final expression of this tensor describes the electrodynamics in the CNT viewed as a low-dimensional surface and is shown to be reduced effectively to a one-dimensional response function.
Theory and Applications of Infinitesimal Dipole Models for Computational Electromagnetics
Said M. Mikki,Ahmed A. Kishk
Physics , 2007, DOI: 10.1109/TAP.2007.895625
Abstract: The recently introduced quantum particle swarm optimization (QPSO) algorithm is employed to find infinitesimal dipole models (IDM) for antennas with known near-fields (measured or computed). The IDM can predict accurately both the near-fields and the far- fields of the antenna. A theory is developed to explain the mechanism behind the IDM using the multipole expansion method. The IDM obtained from single frequency solutions is extrapolated over a frequency range around the design frequency. The method is demonstrated by analyzing conductingand dielectric- type antennas. A calibration procedure is proposed to systematically implement infinitesimal dipoles within existing MOM codes. The interaction of the IDM with passive and active objects is studied through several examples. The IDM proved to predict the interaction efficiently. A closed-form expression for the mutual admittance between similar or dissimilar antennas, with arbitrary orientations and/or locations, is derived using the reaction theorem.
On the Capacity of the Underwater Acoustic Channel with Dominant Noise Sources
Mustafa A. Kishk,Ahmed M. Alaa
Mathematics , 2014,
Abstract: This paper provides an upper-bound for the capacity of the underwater acoustic (UWA) channel with dominant noise sources and generalized fading environments. Previous works have shown that UWA channel noise statistics are not necessary Gaussian, especially in a shallow water environment which is dominated by impulsive noise sources. In this case, noise is best represented by the Generalized Gaussian (GG) noise model with a shaping parameter $\beta$. On the other hand, fading in the UWA channel is generally represented using an $\alpha$-$\mu$ distribution, which is a generalization of a wide range of well known fading distributions. We show that the Additive White Generalized Gaussian Noise (AWGGN) channel capacity is upper bounded by the AWGN capacity in addition to a constant gap of $\frac{1}{2} \log \left(\frac{\beta^{2} \pi e^{1-\frac{2}{\beta}} \Gamma(\frac{3}{\beta})}{2(\Gamma(\frac{1}{\beta}))^{3}} \right)$ bits. The same gap also exists when characterizing the ergodic capacity of AWGGN channels with $\alpha$-$\mu$ fading compared to the faded AWGN channel capacity. We justify our results by revisiting the sphere-packing problem, which represents a geometric interpertation of the channel capacity. Moreover, UWA channel secrecy rates are characterized and the dependency of UWA channel secrecy on the shaping parameters of the legitimate and eavesdropper channels is highlighted.
Quantification of the Hysteresis of Macroscopic Fundamental Diagrams and Its Relationship with the Congestion Heterogeneity and Performance of a Multimodal Network  [PDF]
Seham Hemdan, Amr M. Wahaballa, Fumitaka Kurauchi
Journal of Transportation Technologies (JTTs) , 2018, DOI: 10.4236/jtts.2018.81003
Abstract: Recent studies have observed hysteresis loops in the macroscopic fundamental diagram (MFD). In particular, for the same network density, higher network flows occur during congestion onset than during congestion offset. To evaluate management strategies using the MFD, investigating the relationship between the size of these loops and network performance is needed. The existing literature has mainly discussed correlating loop width (difference in density) and height (capacity drop) with congestion heterogeneity, but has failed to prove a relationship between the capacity drop and traffic conditions. Moreover, quantification of the MFD loop in complex multimodal networks has not been investigated. The objective of this paper covers these aspects. We simulated the Sioux Falls network with different mode-share ratios (car and bus users) based on a multi-agent simulation, MATSim. We investigated the relationships between MFD loop size and congestion heterogeneity (standard deviation of density) and network performance (average passenger travel time), and found that both were directly correlated with loop width, while weakly correlated with loop height. Moreover, we divided the MFD loop into two parts according to congestion onset and offset periods and found that the heights of the two parts had opposite effects. Accordingly, we show why the relationship between capacity drop and congestion heterogeneity is not found in the literature. We also found that network performance inversely affected the height of part of the loop while the height of its other part increased with an increase in congestion heterogeneity. These results help to evaluate network performance in the presence of MFD hysteresis, leading to elaborated management decisions.
Ongoing Mutations in Polytreated Metastatic Cancer Patients May Create a New Chance of Treatment with Unexpected Drugs  [PDF]
Mahmoud M. Abbass Ellithy, Amr Shafik Saad, Mahmoud Salah Abdelsalam, Amr Elsebaei
Journal of Cancer Therapy (JCT) , 2018, DOI: 10.4236/jct.2018.911069
Abstract: Objectives: In this study molecular/genomic characteristics were done on new tissue biopsies taken from Egyptian patients with refractory metastatic solid tumors aiming for two end points: To figure out a personalized treatment and to find the percent of discrepancy between the elaborated drugs of potential benefit and that stated in the guidelines. Methods: 22 eligible patients joined the study. (breast = 5, colon = 3, liver = 2, kidney = 2, ovary = 2, sarcoma = 2, metastasis of unknown origin = 2, Tongue = 1, Adrenal cancer = 1, gastric = 1 and lung cancer = 1). Biopsies were subjected to one or more of the following tests; Immunohistochemistry, Chromogenic/Fluorescence in situ Hybridization, Next Generation Sequencing, Sanger Sequencing. Results: Biomarkers and their corresponding drugs with associated potential benefits were detected as following; TUBB3, PGP and TLE3 (indicating potentiality of paclitaxel) in 22% of cases, TS (Antifolates) 18%, TOPO1 (Irinotecan) 14%, RRM1 (Gemcitabine) 13%, MGMT (Temozolomide) 7%, TOPO2 (Doxorubcin) 7%, ERCC1 (Platinum) 6%, BRAF (Vemurafenib) 2%, KRAS and NRAS (anti EGFR) 2%, C-KIT (TKIs potentiality) 1%, hormonal receptors in 5% of cases (Antihormonal potentiality), monoSPARK and polySPARK in 3% of cases indicating nabpaclitaxel potentiality. Potentiality of some drugs (Based on their corresponding biomarkers) was unexpectedly detected as following; Pemetrexed, irinotecan, dacarbazine and temozolomide in breast cancer patients, platinums and taxanes in liver, Taxanes, gemcitabine, fluoropyramidines, pemetrexed, dacarbazine and temozolomide in kidney cancer, Taxanes, gemcitabine, pemetrexed, dacarbazine and temozolomide in cancer colon, irinotecan in cancer tongue, Pemetrexed and irinotecan in adrenal gland cancer. The percentage of drugs of potential benefit that is not stated in the guidelines case by case was as following: Breast (12%, 15%, 23%, 31%, 21%), Colon (38.1%, 26.5%, 27%), Liver (33.5%, 25%), Kidney (15%, 29%), Ovary (1%, 2%) Sarcoma (17%, 53.5%) tongue 35%, adrenal 73.2%, Gastric 27.8% and lung 36%. Conclusion: Studying molecular/genomic
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