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Performance Analysis of Adaptive Rate Scheduling Scheme for 3G WCDMA Wireless Networks with Multi-Operators
Get PDFSharing of 3G network infrastructure among operators offers an alternative solution to reducing the investment in the coverage phase of WCDMA. For radio access network (RAN) sharing method each operator has its own core network and only the RAN is shared. Without an efficient RRM, one operator can exhausts the capacity of others. This paper proposes and analyzes an efficient uplink-scheduling scheme in case of RAN sharing method. We refer to this new scheme as Multi-operators Code Division Generalized Processor sharing scheme (M-CDGPS). It employs both adaptive rate allocation to maximize the resource utilization and GPS techniques to provide fair services for each operator. The performance analysis of this scheme is derived using the GPS performance model. Also, it is compared with static rate M-CDGPS scheme. Numerical and simulation results show that the proposed adaptive rate MCDGPS scheduling scheme improves both system throughput and average delays
Utilizing Extension Character ‘Kashida’ With Pointed Letters For Arabic Text Digital Watermarking
Get PDFThis paper exploits the existence of the redundant Arabic extension character, i.e. Kashida. We propose to use pointed letters in Arabic text with a Kashida to hold the secret bit ‘one’ and the un-pointed letters with a Kashida to hold ‘zero’. The method can be classified under secrecy feature coding methods where it hides secret information bits within the letters benefiting from their inherited points. This watermarking technique is found attractive too to other languages having similar texts to Arabic such as Persian and Urd
Applications of genetic algorithms to optimal multilevel design of MPLS-based networks
No full textThis paper proposes a design methodology based on the application of genetic algorithms (GA) to find a minimal-cost topological structure of MPLS-based networks. MPLS technology is currently deployed in designing the backbone infrastructure of service provider networks whereas other parts of the network are still operated using the traditional IP protocol. This makes the overall topological structure of MPLS-based networks naturally breaks into two prime sub-problems: access network design and backbone network design. The ultimate goal is to identify the locations of label-edge routers and label-switching routers, and to determine the interconnection links and their capacities to accommodate expected traffic demands. The locations of label edge routers depend on the demands of a given set of terminal networks which in turn affect the design of the backbone network. This problem is a highly constrained NP-hard optimization problem for which exact solution approaches do not scale well. We first present a multilevel design model that divides the optimal topology design into a set of linear programs. Then, we propose GA-based meta-heuristics for solving them. We also discuss the impact of encoding methods and genetic operators and parameters on the performance. Numerical results for the considered cases show that the proposed methodology is effective and gives optimal or close to optimal solutions as compared with the exact branch and bound method
Solving the minimum-cost constrained multipath routing with load balancing in MPLS networks using an evolutionary method
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Hardware Implementations of GF(2^m) Arithmetic using Normal Basis
No full textThis study presents a survey of algorithms used in field arithmetic over GF (2m) using normal basis and their hardware implementations. These include the following arithmetic field operations: addition, squaring, multiplication and inversion. This study shows that the type II Sunar-Koc multiplier is the best multiplier with a hardware complexity of m2 AND gates + XOR gates and a time complexity of TA+ (1+ l log2 (m) l )Tx. The study also show that the Itoh-Tsujii inversion algorithm was the best inverter and it requires almost log2 (m-1) multiplications
Asynchronous MMC based Parallel SA Schemes for Multiobjective Standard Cell Placement
Get PDFAbstract- Simulated Annealing (SA) is a popular iterative heuristic used to solve a wide variety of combinatorial optimization problems. However, depending on the size of the problem,it may have large run-time requirements. One practical approach to speed up its execution is to parallelize it. In this paper we develop parallel SA schemes based on the Asynchronous Multiple-Markov Chain model (AMMC) described in [1] and applied to standard-cell placement in [2]. The schemes are applied to solve the multi-objective standard cell placement problem using an inexpensive cluster-of-workstations environment. This problem requires the optimization of conflicting objectives (interconnect wire-length, power dissipation, and timing performance), and Fuzzy logic is used to integrate the costs of these objectives Asynchronous Multiple-Markov Chain Parallel SA (or AMMC [3], [4]. Experiments are performed on ISCAS-85/89 benchmark circuits. Our goal is to develop parallel SA schemes that provide significantly improved runtime/solution quality characteristics for this key CAD problem, by making the best possible use of an a cluster-of-workstatons environment [2]. inexpensive parallel environment
Simultaneous Stabilization Of Power System Using UPFC-Based Controllers
Get PDFThis article studies the use of robust UPFC-based stabilizers to damp low frequency oscillations. The potential of the UPFC-based stabilizers to enhance the dynamic stability is evaluated by singular value decomposition. Particle swarm optimization technique is used to optimize the parameters of each stabilizer, first individually, then concurrently. To ensure the robustness of the proposed stabilizers, the design process considers a wide range of operating conditions. The effectiveness of the proposed controllers is verified through several linear and nonlinear analysis techniques. These techniques prove that the coordinated design of UPFC-based stabilizers is superior over any of the individual designs
"A Systematic Approach to Nuclear Microscopy of Water Trees for a Large Number of Field-aged HV Cable Samples"
Get PDFIn order to perform micro-PIXE measurements on water trees in underground HV cables when a large number of cable samples are involved, a sequence of tests has been devised to minimize time and effort for sample preparation, water tree detection and analysis. These tests include electrical diagnostic tests to predict the possible presence of water trees, optical microscopy on cable insulation to detect water trees in the samples screened by the electrical tests, scanning electron microscopy for detailed surface topography of water trees, and nuclear microscopy for elemental composition and distribution maps of water trees. Correlations among the results of the four types of measurements are discussed to evaluate the usefulness of the methodolog