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- 저자 : Elmustafa, A. A. (검색결과 6 건)
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Elmustafa S.Ali Ahmed,Bakhita El.Sheikh Ali,Eman Omer Osman,Tagwa Amin M. Ahmed 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.2
Wireless systems continue to rapidly gain popularity. This fact is extremely true for data networks in the local and personal areas. Media Access Control (MAC) layer protocols have a critical role in making a typical Mobile ad hoc network and Personal ad hoc network more reliable and efficient. Choice of MAC layer protocol and other factors including number of nodes, mobility, traffic rate and playground size dictates the performance of a particular WLAN and WPAN. The aim of this paper is to analysis the performance of mobility models in IEEE802.11 MAC and IEEE 802.15.4 ZigBee MAC using NS2.34.These mobility models are RPGM, RWM, Freeway mobility and city section mobility model. Then extraction of the simulation results based on the performance metrics to calculate a Packet Delivery Ratio, data loss, end-to-end delay and Throughput.
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Fracture toughness of amorphus SiC thin films using nanoindentation and simulation
Mamun, M.A.,Elmustafa, A.A. Techno-Press 2020 Advances in materials research Vol.9 No.1
Fracture toughness of SiC on Si thin films of thicknesses of 150, 750, and 1500 nm were measured using Agilent XP nanoindenter equipped with a Dynamic Control Module (DCM) in Load Control (LC) and Continuous Stiffness Method (CSM) protocols. The fracture toughness of the Si substrate is also measured. Nanovision images implied that indentations into the films and well deep into the Si caused cracks to initiate at the Si substrate and propagate upward to the films. The composite fracture toughness of the SiC/Si was measured and the fracture toughness of the SiC films was determined based on models that estimate film properties from substrate properties. The composite hardness and modulus of the SiC films were measured as well. For the DCM, the hardness decreases from an average of 35 GPa to an average of 13 GPa as the film thick increases from 150 nm to 1500 nm. The hardness and moduli of the films depict the hardness and modulus of Si at deep indents of 12 and 200 GPa respectively, which correlate well with literature hardness and modulus values of Si. The fracture toughness values of the films were reported as 3.2 MPa√m.
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Impact of Power Consumption in Sensors Life Time for Wireless Body Area Networks
Lana Ibrahim,Hana Osman,Abdala Osman,Elmustafa Sayed Ali 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.8
Wireless body area network (WBAN) is a communication standard optimized for low power devices and operation on, in or around the human body but not limited to humans used to serve a variety of applications including medical, consumer electronics, entertainment and other[1]. The challenge of WBAN is that the energy of the sensors is limited by the battery life that’s why the transmitting of data is not continuous for long time. This leads to poor efficiency of the WBAN because the continuous power decreasing is due to network operations. An algorithms such as MAC zigbee802.15.4 and adaptive reliable MAC are important to reduce the replacement of batteries many times and to save power consumption. In this paper we concentrated our study on some type of sensors, they are telosB, mica2, micaz, and imote2 depends on power consumption calculations using mat lab program and based on adaptive reliable MAC. We analyzed the sensors with several nodes and packet sizes, and calculate the lifetimes for all the sensors in WBAN. The results we obtained show a good performance of using Adaptive reliable MAC in Wireless Body Area Networks.
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Exploratory Investigation for Some Universities' E-Learning Systems during Covid-19 Pandemic
Fatima Rayan Awad, Ahmed,Thowiba E., Ahmed,Rashid A., Saeed,Elmustafa Sayed, Ali,Ghada Elnour Elterafi, Abdelrhman,Somia Yousif Ahmed, Abutiraima International Journal of Computer ScienceNetwork S 2022 International journal of computer science and netw Vol.22 No.12
COVID pandemic has reshaped the world as it has been known to us and the education system is one of the most affected by it. Due to social distancing, quarantines and isolations have made it impossible for the knowledge transition to the masses using conventional methods. For cope with pandemic, the only other way available for some of the fortunate countries is the use of E-learning having somewhat the same traditional teaching method. This paper is concerned with the study of the preparedness of the learning system in some Sudanese universities due to the impact of the COVID-19 pandemic. Critical analysis has been performed to evaluate the current developing scenario, usage of the facilities available in open-source platforms, and the interaction of the universities folks with e-learning systems. The impact of such measures has been thoroughly investigated in this paper for Sudan which is already deprived of a proper education system. The investigation shows that the interact of the staff and the students with the system was acceptable where more than 85% of those enrolled to the system were interact properly and efficiently. The lecturers conducted through the platform were attended with more than 75% of the students. We also found that most of the lecturer were avoid to exam students by utilize the platform; where only 45% of the uploaded courses were conducted exams over Moodle platform. As Moodle is an open source and still need to be improved to be used for high examination credibility.
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Abd Elaziz Sulieman Ahmed Ishag,Azhari Omer Abdelbagi,Ahmed Mohammed Ali Hammad,Elsiddig Ahmed Elmustafa Elsheikh,Osama Elgilani Elsaid,허장현 한국응용생명화학회 2017 Applied Biological Chemistry (Appl Biol Chem) Vol.60 No.3
Biodegradation of endosulfan (a and b) and pendimethalin by Bacillus safensis strain FO-36bT, Bacillus subtilis subsp. inaquosorum strain KCTC 13429T and Bacillus cereus strain ATCC14579T isolated from pesticides- polluted soil was studied in mineral salt medium. Endosulfan and pendimethalin were incubated with the three bacterial strains with samples drawn at various intervals for GC analysis. Representative samples were subject to GC–MS analysis. The loss in the initial concentrations, 0.663 mM (a endosulfan), 0.319 mM (b endosulfan) and 1.423 mM (pendimethalin), was monitored and used to compute the half-lives following biphasic model. Removal percentage of endosulfan and pendimethalin in the media inoculated with the bacterial strains ranged from 24 to 95% (a endosulfan), 21–91% (b endosulfan) and 51–97% (pendimethalin), respectively. Despite the significant decrease in starting material in B. safensis cultures, no metabolites were detected, whereas two major metabolites of endosulfan, 1,2,3,4,7,7-hexachloro-5,6- dihydroxybicyclo{2.2.1}-2-heptene and 1,2,3,4,7,7-hexachloro- formaldehyde-6-methylbicyclo{2.2.1}-2-heptene, were detected in the B. subtilis cultures, and one metabolite of pendimethalin metabolite; N-(1-ethylpropyl)-3-methyl- 2, 6-diaminobenzine, was detected in the B. cereus culture. Generally, the result indicates the potential capability of these microorganisms in complete mineralization of endosulfan and pendimethalin. Based on half-lives, the efficiency of bacterial strains can be ordered as follows: B. subtilis[B. cereus[B. safensis for endosulfan and B. cereus[B. safensis[B. subtilis for pendimethalin.
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