المقالات العلمية - كلية الهندسة
Permanent URI for this collectionhttps://repository.neelain.edu.sd/handle/123456789/10362
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Item Blind Source Separation Technique via Parallel Computing(2006-05) Ibrahim Elimam Abdalla, Abubakr Elsidig Mirghani El Hussien; Othman KhalifBlind source separation is one of the more challenging problems in signal processing where mixture of sources, sounds or any type of signals are to be separated and located without any prior information about these sources and the way they have been mixed, hence the name blind. Many methods and algorithms have been developed to tackle this problem, they are mostly complicated and computational expensive. The main aim of this paper is to study and compare these techniques that are currently used in source separation, highlighting their advantages and weaknesses. A parallel computing approach is introduced as an efficient way to enhance the current techniques of blind source separation. The benefits of the proposed technique are discussed.Item Investigation of the Impact of Bad Learning on Blind Source Separation(2007-03) Ibrahim Elimam Abdalla, Abubakr Elsidig Mirghani El Hussien; Othman Khalifa, Aisha Hassan AbdallaBlind source separation is one of the more challenging problems in signal processing where mixture of sources, sounds or any type of signals are to be separated and located without any prior information about these sources and the way they have been mixed. Any blind source separation algorithm consists of a contrast or cost function plus an adaptation or learning rule which is used to minimize or maximize the cost function so as to perform separation. This typically used in human being brains to distinguish between the different voices and scenes. Here we introduce an approach that explains some strange natural phenomena and relate their occurrence to what is called bad learning in the process of blind source separation.Item Parallel Algorithm for Blind Source Separation(2008) Ibrahim Elimam Abdalla, Abubakr Elsidig Mirghani El Hussien; Aisha Hassan AbdallaIn Blind Source Separation a mixture of sources, sounds or any type of signals are to be separated without any prior information about these sources and the way they have been mixed. Most of the methods and algorithms that have been developed to tackle this problem are computationally expensive. Specially those dealing with Convolutive Blind Source Separation. Here, a new parallel, computationally none expensive Convolutive Blind Source Separation algorithm is presented and evaluated. Then parallelization of an already existing Blind Source separation algorithm is also presented and tested.Item Measurements of RF/MW Radiation Emitted from Selected Mobile-Phone Base-Stations in Sudan(2008-10) S.T. Kafi, A.M.Ahmed; Ibrahim.E.AScattering of mobile-phone base-stations within populated areas is a source of some misscomfortableness to many people. As there is no one agreed on safety level for the MPE for RF/MW allover the world, measurements of radiation emitted from base-stations is a necessity. In this work we screened out some mobile-phone base-stations inside and outside Khartoum city in Sudan. Measurements were done indoor and outdoor to maximum horizontal distance of about 300 m from the base of the base-stations. Results obtained were then compared to the maximum and minimum MPE values admitted in different countries in the world. The maximum MPE value (i.e- 0.57 mW/cm2) consider only the thermal effects of the RF/MW, while other values tend to reduce the exposure limits to as minimum as possible for safety considerations (considering non-thermal effects). Some of the values obtained were consistent with some reported biological effects. We recommended the removal of some base-stations from sensitive areas like schools, kindergardens, hostels, hospitals, etc.Item Performance Evaluation of Voice and video conferencing For WIMAX Network under Various Modulation techniques(2016-08) Almutaz Ali Mohammed, Ibrahim Elimam AbdallaWorldwide interoperability for Microwave Access (WIMAX) that based on 802.16d/e Orthogonal Frequency Division Multiplexing (OFDM) and based on adaptive Physical Layer (PHY), It provides wireless broadband to fixed and mobile terminals, The basic WIMAX feature is wireless transmission infrastructure which allows a fast use as well as low maintenance costs, Modulation techniques enable WIMAX network to be optimized. WIMAX supports BPSK, 16-QAM, DPSK, and 64-QAM as a modulation technique. This paper present evaluation of various modulation techniques and study of performance for voice and video conferencing applications, An Opnet software used to simulate WIMAX Modulation techniques impact on voice and video conferencing, The simulation results includes the performance analysis for bit error rate (BER), SNR, MOS, MOS loss Rate, end to end packet delay and Jitter of different modulationItem Performance Analysis of FTP, HTTP and Database for IEEE802.11, IEEE802.11a, IEEE802.11b and IEEE802.11g using OPNET Simulator(2016-08) Almutaz Ali Mohammed1, Ibrahim Elimam AbdallaAbstract: WLAN is the most exceedingly accepted broadband wireless technology that can offer a high transmission rate; Wi-Fi provides its users with option of connecting to the Internet from any place without wires. This paper presents a performance analysis of WLAN in a simulated office for different applications (FTP, Database and HTTP) for various WLAN standards(802.11b, 802.11a, 802.11g, 802.11 infrared and 802.11 frequency hopping), OPNET 14.5 tool was used to design the network that consists of a number of access points each of them supports different WLAN technology standards, deployed to serve the needs of workstations that work with same AP standard with maximum data rate adopted by this standard. From the simulation, we focused to find out some metrics namely Database, FTP and HTTP download - upload response times, WLAN load, WLAN delayed, WLAN throughput, Media access delay, TCP abort and queuing size.