Mohamed Mokhtar

Ain Shams University

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Mostafa I. Marei

Ain Shams University

Naofal Al‐Dhahir

The University of Texas at Dallas

Mostafa F. Shaaban

American University of Sharjah

Mahmoud A. Attia

Ain Shams University

Ahmed A. El-Sattar

Ain Shams University

Ridha Hamila

Qatar University

Ahmed H. El-Ebiary

Ain Shams University

Hatem Zeineldin

Khalifa University of Science and Technology

Ehab F. El‐Saadany

Khalifa University of Science and Technology

Mohamed R. M. Rizk

Alexandria University

Cooperative Institutions

Ain Shams University

Alexandria University

Cairo University

Arab Academy for Science, Technology, and Maritime Transport

American University of Sharjah

Universiti Putra Malaysia

Military Technical College

University of Waterloo

Helwan University

Zagazig University

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Scattering of Ultrasonic Waves in Gases

The Journal of the Acoustical Society of America (1950)

Mohamed Mokhtar Mohamed Shehata

Ultrasonic beams of frequencies in the range of 80 kc/sec. to 1000 kc/sec. emerge from a rectangular slit of known adjustable width into air, oxygen, or carbon dioxide. The disposition of the field in front of the slit is studied by the aid of a hot wire anemometer, which gives the angle of divergence of the beam and the intensity distribution across the main and the diffracted beams. The results obtained indicate that the laws of diffraction are valid so long as the gas is far removed from its anomalous dispersion region. CO2 in the range between 100 and 200 kc/sec. shows a high degree of scattering with the result that the emergent beam loses its definition completely and becomes very diffused.

Anemometer

Intensity

10.1121/1.1906566

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Citations (3)

Dual-hop OFDM opportunistic AF relaying under joint transmit/receive I/Q imbalance

2015 IEEE Global Communications Conference (GLOBECOM) (2013)

Mohamed Mokhtar Alexandros‐Apostolos A. Boulogeorgos George K. Karagiannidis Naofal Al‐Dhahir

We study the outage performance of orthogonal frequency-division multiplexing dual-hop opportunistic amplify-and-forward relaying in the presence of I/Q imbalance in all of the nodes' transceivers. We derive a closed-form expression for the end-to-end outage probability for the general case, where each node suffers from a different I/Q imbalance level and under the assumption that the distance between source and relay is not the same for all relays. Our simulation results show excellent match to our analysis and both demonstrate that uncompensated I/Q imbalance can be detrimental but it can also be effectively mitigated using a few relays. This result has a significant impact on relay deployment in future wireless communication networks.

Transceiver

Outage Probability

Expression (computer science)

10.1109/glocom.2013.6831747

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Citations (8)

Effect of Multiple Reflow Cycles and Isothermal Aging on Shear Strength in SAC305/Sn58Bi/Cu-OSP Hybrid Solder Joint

International Journal of Nanoelectronics and Materials (IJNeaM) (2024)

Mohamed Mokhtar Flora Somidin Mohd Arif Anuar Mohd Salleh

This study investigates the effects of multiple reflow cycles and isothermal aging on the shear strength and microstructure of SAC305/Sn58Bi/Cu-OSP hybrid solder joints. The joints combine SAC305 solder spheres and Sn58Bi solder paste reflowed on Cu-OSP substrates. Microstructural analysis revealed two distinct regions: a Bi-rich phase at the bottom and an Ag-rich phase at the top. Reflow cycles and isothermal aging at 85 °C, 125 °C, and 150 °C for up to 120 hours were evaluated for their impact on mechanical performance and reliability. Shear tests at 100 mm/s and 2000 mm/s showed that hybrid joints outperformed conventional SAC305/Cu-OSP joints, even after multiple reflow cycles. Aging at 85 °C and 125 °C had minimal impact on shear strength, indicating good stability under moderate conditions. However, aging at 150 °C, above the melting point of Sn58Bi (138 °C), caused a significant decrease in strength. These findings highlight the potential of hybrid solder joints for improved mechanical performance and thermal stability, offering advantages over conventional solder joints for advanced electronic packaging.

Isothermal process

Shear Strength

10.58915/ijneam.v17idecember.1640

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Citations (0)

High Performance Data Encryption based on Advanced Encryption Standard using FPGA

IOSR Journal of Computer Engineering (2014)

Mohamed Mokhtar

Many digital services, such as confidential video conferencing, medical, military imaging systems and the rapid progress of Internet, require reliable security and encryption in real time to store and transmit these digital images/videos.In this paper, a parallel implementation of the advanced encryption standard (AES) using pipelining technique is proposed.For more security, a pseudo random sequence generator (PRSG) is used in advance.The goal is to achieve a high-speed reliable security system for real time application.The parallel architecture is implemented on Field Programmable Gate Arrays (FPGA) family of Spartan_6 (XC6SLX16) using Very high speed Hardware Description Language (VHDL).An image encryption is taken as a case study.The system is capable to process image (256*256) in (0.00053) seconds; consequentially the real time requirement is achieved.

10.9790/0661-16650713

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Citations (2)

A secured chaos encrypted mode-S aircraft identification friend or foe (IFF) system

El‐Sayed A. El‐Badawy Waled El-Masry Mohamed Mokhtar Alaa S. Hafez

This paper introduces a new technique for aircraft identification friend or foe (IFF). The technique is based on using a proposed Chaos Advanced Encryption Standard (AES) with mode-S IFF. AES has a key size of 128 bits and a substitution-linear transformation network with 10 rounds. The sensitivity of the chaos initial condition gives the algorithm the ability to use as a second key. The first key was assigned using a soft look-up table used periodically. The second key was assigned using the date of the current day by both interrogator and the transponder. This technique gives the system more security and confidentiality which is compatible with mode-S IFF interrogation and reply messages format. It requests a new data on the reply signal. This data increase the radar performance for detection and tracking the friend targets in active and passive jamming environments. The results obtained from this technique on the simulated interrogator and transponder signals shows that this scheme can be easily implemented and provide the air defence system a secured aircraft authentication.

Transponder (aeronautics)

Secondary surveillance radar

Identification

Mode (computer interface)

Table (database)

10.1109/icspcs.2010.5709756

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Citations (14)

UAV positioning for out-of-band integrated access and backhaul millimeter wave network

Physical Communication (2019)

Mai A. Abdel-Malek Ahmed S. Ibrahim Mohamed Mokhtar Kemal Akkaya

Backhaul (telecommunications)

Access network

10.1016/j.phycom.2019.100721

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Citations (16)

An Adaptive Control of Remote Hybrid Microgrid based on the CMPN Algorithm

Electric Power Systems Research (2022)

Sayed Mohamed Mohamed Mokhtar Mostafa I. Marei

Microgrid

Robustness

Voltage controller

10.1016/j.epsr.2022.108793

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Citations (19)

REAPPRAISAL OF GEARS LUBRICATION IN LIGHT OF ELASTOHYDRODYNAM1C THEORIES

The International Conference on Applied Mechanics and Mechanical Engineering (1984)

H. HANNA Mohamed Mokhtar Amr Kotb

10.21608/amme.1984.49114

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Citations (0)

The Acoustic Characteristics of Conical Pipes

Proceedings of the Physical Society Section B (1949)

Mohamed Mokhtar G Abdel Messih

The paper describes an experimental investigation on slightly tapering conical pipes used as sound transmitters, undertaken in order to determine their acoustic characteristics, their end corrections and the pressure variation along the inside of the pipes.

Tapering

Variation (astronomy)

10.1088/0370-1301/62/12/304

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Citations (4)

On I/Q imbalance effects in full-duplex OFDM decode-and-forward relays

Mohamed Mokhtar Naofal Al‐Dhahir Ridha Hamila

We analyze the outage probability of dual-hop full-duplex decode-and-forward relaying for an orthogonal frequency division multiplexing system in the presence of I/Q imbalance. We derive accurate analytical approximations which quantify the outage probability's functional dependence on the I/Q imbalance level and the residual loopback self-interference average power level. In addition, we derive the condition at which direct transmission outperforms full-duplex decode-and-forward relay-assisted transmission in the presence of I/Q imbalance. Finally, our numerical results confirm the accuracy of our analysis.

Outage Probability

Duplex (building)

10.1109/dcas.2014.6965343

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Citations (4)