oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 373 )

2018 ( 548 )

2017 ( 546 )

2016 ( 770 )

Custom range...

Search Results: 1 - 10 of 325704 matches for " Hamdy S Soliman "
All listed articles are free for downloading (OA Articles)
Page 1 /325704
Display every page Item
Exponential Brute-Force Complexity of A Permutation Based Stream Cipher
Mohammed Omari,Hamdy S. Soliman
International Journal of Computer Network and Information Security , 2013,
Abstract: This paper introduces a permutation generation mechanism based on a shared secret key. The generated permutation vectors are used as encryption keys in a stream ciphering cryptosystem. We investigated various types of attacks on the known stream cipher RC4 and patched most of its loopholes, especially biased-byte and state-related attacks. Unique to our approach, we prove mathematically that the complexity of brute-forcing such a system is (2n), where n is the key size in bytes. This paper also presents a complete security model using permutation-based encryption, in order to handle privacy. In addition, our approach achieved higher performance than that of existing peer techniques, while maintaining solid security. Experimental results show that our system is much faster than the existing security mechanisms, such as AES and DES.
Application of Synchronous Dynamic Encryption System (SDES) in Wireless Sensor Networks
Hamdy S Soliman,Mohammed Omari
International Journal of Network Security , 2006,
Abstract: Inherent to the wireless sensor networks are the two major problems of the broadcasting vulnerability, the limited computational capability and power budget. Even though security is a must in most applications, current sophisticated security protocols are not amenable to the primitiveness of the sensors. In this paper, we introduce a novel security protocol for wireless network of sensors that is very secure, yet simple and efficient. At the core of our security protocol is a simple and fast stream cipher cryptosystem that utilizes permutation vectors as encryption keys, forcing an intruder to a brute-force time complexity of $Omega(2^n)$. In addition, our mechanism alleviates the effect of sensor capture, via its synchronized re-keying feature. In addition to the encryption efficiency, our system utilizes the group deployment of newly joining sensors for sensors power budgeting considerations. Experimental results show very promising future of our system in the wireless networks domain, excelling over other peers of modern cryptosystems (AES, DES, TripleDES), especially in the power budget arena.
Optimum Remedial Operation of Permanent Magnet Synchronous Motor
Hamdy Mohamed Soliman,S. M. EL. Hakim
International Journal of Electrical and Computer Engineering , 2012, DOI: 10.11591/ijece.v2i5.725
Abstract: In critical systems, the reliability of the drive is very important. The faults are unwanted. The faults may be lead to loss of the human life and capital. This paper is addressed this problem and suggested two models to solve it. The first model doesn’t contain any special tools to improve the torque ripple and THD. The second model contains 2PI current controllers to improvement the performance at fault and remedial operation. One is for the torque and the other is for the flux. The first PI controller is feeding from the torque error between the reference and estimated torques to get new q-axis current component representing modifier current arises from uncertain things inside the machine and drive system such as temperature and parameters variations. This current will add to reference q-axis current to get robust new q-axis current to satisfy the drive requirement and solve the torque problem (ripple torque). With robust current, the total harmonic distortion is a decrease but doesn’t reach the best value so the other PI controller is used to adjust the THD. In this PI controller, the d-axis flux is compared to rotor permanent magnet flux to solve this problem arises from non-sinusoidal of the magnetic flux. The output of the PI controller is introduced to the reference d-axis current. The new d-axis current will reach the best value of THD. The simulation of the second controller is compared to the simulation of first controller to show if the second controller strong or weak. Matlab simulink is used to simulate the drive system.
Improvement the Current Control Methods for Three Phase Voltage Source Inverter to Drive the Permanent Magnet Synchronous Motor
Hamdy Mohamed Soliman,S. M.EL. Hakim
International Journal of Engineering and Advanced Technology , 2012,
Abstract: Three phase pluse width modelation voltage soruce inverter are widly used in many industrial application such as the drive system. The performance of the drive systems depend up on the motor control and method of control in power converter. From the most important methods to control the power converter are current and voltage controls. The current control is preferable. This is because it is simple. The quality control of this method depends upon the quality of the waveform is generated by current controlled of converter. This paper aims to improve the performance of Ac drives through the improvement the different methods of the current controlled. Here the classical hysteresis controller, ramp type controller and delta modulator controller are discussed and improvement by general design of PI current controller for each phase. The improvement can be seen through the torque ripple and total harmonic distortion. The proposed model is compared to classical model to show the effectiveness of the proposed model. This work is simulated through matlab simulink.
Identification of Stator Winding Faults and Remedial Operation of Permanent Magnet Synchronous Motors with Suppress Noise and Ripple
Hamdy Mohamed Soliman,S. M.EL. Hakim
International Journal of Soft Computing & Engineering , 2012,
Abstract: The reliability of the drive system is very important in critical systems. The faults in these systems are unwanted and the drive system must be operated under the fault conditions. If fault occurs this may be lead to loss of the human life and capital so the detection of this fault, separation the faulty part and method invention for remedial operation is very important. In this paper the performance of a permanent magnet synchronous motor drive under a stator winding fault is studied and a negative sequence is used to detect the different types of the faults in that winding. This paper is suggested two models for solving these faults. The control in these models depends upon the controlling in each phase separately. The first model doesn’t contain any special tools to improve the torque ripple and THD. The second model contains 2PI current controllers to improvement the performance at fault and remedial operation. One is for the torque and the other is for the flux. The first PI controller is feeding from the torque error between the reference and estimated torques to get new q-axis current component representing modifier current arises from uncertain things inside the machine and drive system. This current will add to reference q-axis current to get robust new q-axis current to satisfy the drive requirement and solve the torque problem (ripple torque). With robust current, the total harmonic distortion is a decrease but doesn’t reach the best value so the other PI controller is used to adjust the THD. In this PI controller, the d-axis flux is compared to rotor permanent magnet flux to solve this problem arises from non-sinusoidal of the magnetic flux. The output of the PI controller is introduced to the reference d-axis current. The new d-axis current will reach the best value of THD. The simulation of the second controller is compared to the simulation of first controller to show if the adding the 2 PI current controllers is profit or not. Here the matlab simulink is used to simulate the drive system.
Hysteresis Current Controller, PI Controller, PMSM, Torque Ripple
Hamdy Mohamed Soliman,S. M.EL. Hakim
International Journal of Soft Computing & Engineering , 2012,
Abstract: Hysteresis current controller is used in many industrial applications because it has many advantages as fast, high dynamic performance and doesn’t require any information about load parameters. The draw back of this current controller is varying switching frequency. This paper presents adaptive hysteresis current controller to control the inverter. It is used to reduce the ripple, total harmonic distortion and improvement the switching frequency through design of PI current controller. The performance of the drive system due to improvement in the hysteresis current controller is simulated through the matlab simulink. The modified hysteresis current controller is compared to conventional hysteresis controller under steady state and transient conditions with fixed load, sudden applied and sudden removal load and reversing load to show the effectiveness of this modification.
Routeless Routing Protocols Over MASNETs: More Energy Saving Approaches
Mohammad AlOtaibi,Hamdy Soliman
International Journal of Wireless & Mobile Networks , 2010,
Abstract: In this paper, two efficient hybrid routeless routing protocols (static and adaptive channel width) forMobile Ad hoc Sensor Networks (MASNETs) have been proposed. They are based on Location-AidedRouting (LAR) and Received signal strength-Aided Flooding (RAF) protocols. Our protocols maintaingeographical Route Broadcasting Virtual Channels (RBVC) with different widths between a source nodeand its destination to reduce the rebroadcasts of packets. Hence without predefined source-destinationroute, i.e., routeless, only some nodes, inside the RBVC, may contribute in rebroadcasting packets.Simulation results show that our protocols are able to outperform both RAF and LAR based protocolswith respect to energy consumption and packet delivery ratio.
Physico-Chemical, Organolyptical and Microbiological Characteristics of Substituted Cupcake by Potato Processing Residues  [PDF]
Ibrahim Khalifa, Hassan Barakat, Hamdy A. El-Mansy, Soliman A. Soliman
Food and Nutrition Sciences (FNS) , 2015, DOI: 10.4236/fns.2015.61010
Abstract: Utilization of potato processing residues to produce a low caloric cupcake in present study was targeted. The functional properties of wheat flour (WF 72%) and dried potato peel varieties [Hermus (PPH) and Russet (PPR)] were carried out. Consequently, WF was partially substituted by both potato peels (PP) at 5% - 20% to prepare mixtures for cupcake making. Approximate chemical composition and physical characteristics were determined. Rheological parameters of prepared formulas were assayed using Mixolab. Moreover, total phenolic compounds (TPC) and relative antioxidant activity (AOA) were evaluated. Quality parameters such as thiobarbituric acid (TBA), staling and microbiological attributes during storage were determined. In addition, a sensory evaluation of different substituted cupcake was performed as well. Results indicated that PPR had the highest water absorption capacity (WAC), oil absorption capacity (OAC) and swelling capacity (SC) followed by PPH then WF flours. Indeed, substituted WF with both PP at 5% and 10% didn’t influence the thermo-mechanical properties including dough time development, stability, viscosity, gluten and starch characteristics drastically. Likewise, this substitution levels didn’t affect the organoleptic properties which were confirmed by panelists, cupcake external and cross sections. Substituted WF by 5% - 10% PP recorded sensory scores aftermost WF. Mildly, WF cupcake was higher in protein and fat contents than WF-PP cupcakes while lower in crude fiber. The WF-PP cupcakes at different substituted levels recorded lower energy value than WF cupcakes. Arguably, increasing both PP levels increased the TPC and AOA especially for WF-PPR cupcakes. Afterwards, WF-PPR 15% and 20% recorded the highest TPC and AOA contents to be 2.32 mg GAE g-1 dw and 3.44 μmol TE g-1 dw, respectively. No significant difference (p > 0.05) was found between WF-PP at 5% and WF cupcakes in physical and staling properties. WF-PPR cupcakes at different concentrations were lower TBA than WF cupcakes and mostly stable during storage period. It was revealed that substitution levels of 5% and 10% with PPH and PPR produced acceptable cupcakes which did not significantly differ from WF cupcakes.
Design of Robust Power System Stabilizer Based on Particle Swarm Optimization  [PDF]
Magdi S. Mahmoud, Hisham M. Soliman
Circuits and Systems (CS) , 2012, DOI: 10.4236/cs.2012.31011
Abstract: In this paper, we examine the problem of designing power system stabilizer (PSS). A new technique is developed using particle swarm optimization (PSO) combined with linear matrix inequality (LMI). The main feature of PSO, not sticking into a local minimum, is used to eliminate the conservativeness of designing a static output feedback (SOF) stabilizer within an iterative solution of LMIs. The technique is further extended to guarantee robustness against uncertainties wherein power systems operation is changing continuously due to load changes. Numerical simulation ahs illustrated the utility of the developed technique.
Physical Factors Affecting the Interior Radon-Concentrations  [PDF]
Soliman M. S. Abdalla, Saddig D. Jastaniah
Open Journal of Biophysics (OJBIPHY) , 2013, DOI: 10.4236/ojbiphy.2013.31004
Abstract:

Researchers have realized that radon-contaminated air inside buildings is a principal way of human exposure to certain healthy-risks. A model is developed to estimate radon concentrations which consider various parameters: in indoor air radon (radon-222) concentration, air permeability of ground, air pressure difference between outdoor and indoor at ground level, ventilation of building ground and number of air changes per hour due to ventilation. The radon-222 transport into building might dominated by diffusion, pressure driven flow or/and a mixture of both depending on the actual values of the various parameters. So, in several and regular periods of time: January, April, July and October, radon-222 concentrations have been measured in ten rooms of five elementary schools and in five rooms of one high school at Qena city (Upper Egypt). This has been carried out using alpha scintillation counters. We have noticed that in three rooms the value has exceeded 200 Bqm -3 at the basement and only one room at the first floor, and all values have changed with respect to time and localization: They have decreased from July to January and from basement to first floor. For example, radon-222 concentrations obtained by exposing track detectors varied in the range from 20 Bqm-3 up to 100 Bqm-3. The experimental results of the present work have been well fitted with the presented model (calculations) which supports the validity of the presented model. So, to decrease the level of indoor air radon-222 concentrations and to reduce its harmful effects it is recommended to follow the suggestions in the present study and to limit as possible the use of ceramic in the building construction, increase the hours of ventilation and to restrict the use of underground floors in buildings, the underground Metro and garage parking should be carefully (and even mandatory) ventilated.

Page 1 /325704
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.