PHD theses : Engineering

Permanent URI for this collectionhttps://repository.neelain.edu.sd/handle/123456789/507

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    A New Algorithm for Blind Source Separation Using Parallel Processing
    (Neelain University, 2006) Ibrahim Elimam Abdalla
    ABSTRACT In this dissertation the digital filters were used to solve the Convolutive Blind Source Separation within the parallel computing context, A revision of the strategy of tackling BSS and CBSS problems via parallel computing was proposed. In this dissertation a convolutive Blind Source Separation algorithm was developed within the context of parallel computing. The algorithm finds the demixing system by simultaneously jointly diagonalizeing a set of time-lagged correlation matrices by using parallel form of Jacobi plane transformations. The parallel computing approach was applied on some existing BSS and CBSS algorithms. As an example of the iterative CBSS algorithms Lambert and Bell work was selected and modified so as to apply parallel computing approach. Very good results were obtained compared with Lambert and Bell results. A very important improvement is that the developed equalizing system converges very fast. As an example of the diagonalization algorithms the JADE algorithm was modified to apply parallel computing approach. The results of the simulations showed that applying parallel computing approach on this type of algorithms is easier if done on shared memory systems.
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    RESIDUAL SERVICE TIME BASED ANALYSIS OF MULTI-CLASS MULTI-SERVER PRIORITY . QUEUING SYSTEMS
    (Neelain University, 2007) Amin Babiker A/Nabi Mustafa
    ABSTRACT In this research, Multi-Class Multi-Server Priority Queuing Systems. service times for all priority classes are assumed to be identically and exponentially distributed. This assumption led to the possibility of extending the analysis of non- preemptive priority queuing systems to the multiple servers case (similarly to multiple communication channels). ' The extension is based on the developed fomiula for the residual service time R. This on its part, was achieved by utilizing the analysis of M/M/m systems in which the service times are identically and exponentially distributed, combining this with the analysis of non-preemptive queuing systems for single server systems based on M/G/l system. Making all necessary modifications for the system to fit the multiple servers case, the necessary mathematical analysis and derivations were given. The Preemptive Priority queues with Multiple Servers and Multiple priority classes were treated in the same manner. Here the assumption that the service times - for all priority classes — are identically and exponentially distributed _is put forward. Again, a formula for the residual service time is developed and utilized in calculating the average customer waiting time and other related parameters. In the light of this assumption the author presents the relations necessary to derive an expression for the mean residual service time which is then used in developing a mathematical model for the analysis of preemptive priority queues with multiple servers and multiple priority classes. The research includes some comparative studies between the proposed model (multi-class multi-servers priority queuing systems) and some prior related works.
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    A New Algorithm for Blind Source Separation Using Parallel Processing
    (Al Neelain University, 2006-11) Ibrahim Elimam Abdalla
    In this dissertation the digital filters were used to solve the Convolutive Blind Source Separation within the parallel computing context, A revision of the strategy of tackling BSS and CBSS problems via parallel computing was proposed. In this dissertation a convolutive Blind Source Separation algorithm was developed within the context of parallel computing. The algorithm finds the demixing system by simultaneously jointly diagonalizeing a set of time-lagged correlation matrices by using parallel form of Jacobi plane transformations. The parallel computing approach was applied on some existing BSS and CBSS algorithms. As an example of the iterative CBSS algorithms Lambert and Bell work was selected and modified so as to apply parallel computing approach. Very good results were obtained compared with Lambert and Bell results. A very important improvement is that the developed equalizing system converges very fast. As an example of the diagonalization algorithms the JADE algorithm was modified to apply parallel computing approach. The results of the simulations showed that applying parallel computing approach on this type of algorithms is easier if done on shared memory systems.