IJMECS Vol. 5, No. 9, Sep. 2013
Cover page and Table of Contents: PDF (size: 611KB)
In this paper, the detailed overview of the database replication is presented. Thereafter, PDDRA (Pre-fetching based dynamic data replication algorithm) algorithm as recently published is detailed. In this algorithm, further, modifications are suggested to minimize the delay in data replication. Finally a mathematical framework is presented to evaluate mean waiting time before a data can be replicated on the requested site.[...] Read more.
Cognitive radio is an efficient technique for realization of dynamic spectrum access. Since in the cognitive radio network (CRN) environment, the secondary users (SUs) are susceptible to the random jammers, the security issue of the SU’s channel access becomes crucial for the CRN framework. The rapidly varying spectrum dynamics of CRN along with the jammer’s actions leads to challenging scenario. Stochastic zero-sum game and Markov decision process (MDP) are generally used to model the scenario concerned. To learn the channel dynamics and the jammer’s strategy the SUs use reinforcement learning (RL) algorithms, like Minimax-Q learning. In this paper, we have proposed the multi-agent multi-band collaborative anti-jamming among the SUs to combat single jammer using the Minimax-Q learning algorithm. The SUs collaborate via sharing the policies or episodes. Here, we have shown that the sharing of the learned policies or episodes enhances the learning probability of SUs about the jammer’s strategies but reward reduces as the cost of communication increases. Simulation results show improvement in learning probability of SU by using collaborative anti-jamming using Minimax-Q learning over single SU fighting the jammer scenario.[...] Read more.
Providing the security on the basis of encryption standards is considered as key challenges for achieving the integrity & confidentiality. There are three main public-key cryptosystem contenders. Each has a variable key size that can be increased to achieve higher security at the cost of slower cryptographic operations. The best attack known on each public-key cryptosystem requires an amount of computation determined by a security parameter which is related to the key size. The secondary factor is confidentiality i.e. ensuring that adversaries gain no intelligence from a transmitted message. There are two major techniques for achieving confidentiality:
This work proposes a novel prototype ECDSA which provides the security where there is not complete trust between documents’ sender and receiver & something more than authentication is needed. The signature is formed by taking the hash of the message and encrypting the message with the creator’s private key. It guarantees the source and integrity of the message. Then a suitable digital signature algorithm will be picked out as a result of comparing and analyzing three main digital signature algorithms in this paper. Finally, a scheme of digital signature in electronic government will be proposed in order to settle some specific problems such as spilling out the secret, forging or denial and so on. Besides, a brief analysis regarding security will be given for this scheme.
Based on the research of Power-cycle Nested Graph C6m×P6m, the decomposition method of single point sector has come up. By the use of the process of clawed nested-cycle sub-graph, the edge-balanced index sets of the power-cycle nested graph C6m×P6m are solved when m ≥4 and m=4(mod5) . Besides, the constructive proofs of the computational formulas are also completed. The theory can be applied to information engineering, communication networks, computer science, economic management, medicine, etc. The proving method can be a reference to solve the problem of the power-cycle nested graph C6m×P6m.[...] Read more.
For the past few decades we have seen the evolution of user interfaces from CLI (Command Line Interface) to GUI (Graphical User Interface) to the most recent NUI (Natural User Interfaces). One such example is Surface Computing. Surface computing is a new way of working with computers that moves beyond the traditional mouse-and-keyboard experience. It is a natural user interface that allows people to interact with digital content with their hands, with gestures and by putting real-world objects on the surface. Though very convenient and simple to use, the cost of this technology is one of the major hindrances in making it accessible to common users. Microsoft PixelSense is an excellent example of this technology. For making this technology cost efficient and more accessible, we have designed an interactive table. It allows two mobile phones to interact with each other, i.e. one can share mobile content just by placing two phones on the table and dragging the content from one phone to another using their fingers. Instead of the usual resistive and capacitive touchscreens used these days, it uses an imaging touch screen, i.e. image processing is used to determine the fingertip coordinates and handle data according to these coordinates thereby decreasing the cost of this technology sharply.[...] Read more.
Face recognition is the most successful form of human surveillance. Face recognition technology, is being used to improve human efficiency when recognition faces, is one of the fastest growing fields in the biometric industry. In the first stage, the age is classified into eleven categories which distinguish the person oldness in terms of age. In the second stage of the process is face recognition based on the predicted age. Age prediction has considerable potential applications in human computer interaction and multimedia communication. In this paper proposes an Eigen based age estimation algorithm for estimate an image from the database. Eigenface has proven to be a useful and robust cue for age prediction, age simulation, face recognition, localization and tracking. The scheme is based on an information theory approach that decomposes face images into a small set of characteristic feature images called eigenfaces, which may be thought of as the principal components of the initial training set of face images. The eigenface approach used in this scheme has advantages over other face recognition methods in its speed, simplicity, learning capability and robustness to small changes in the face image.[...] Read more.
One of the methods used in the design and utilization of distribution systems to improve power quality and reliability of load power supply of consumers, is the application of distributed generation (DG) sources. In this paper, a new method is proposed for the design and utilization of distribution networks with DG resources application by finding the optimal sitting and sizing of generated power of DG with the aim of maximization of its benefits to costs. The benefits for DG are considered as system losses reduction, system reliability improvement and benefits from the sale electricity or from lack of purchase of electricity from the main system. The costs of DG are considered as initial capital, maintenance and operation cost and investment cost. In this paper to solve the optimal sitting and sizing problem a Modified particle swarm optimization (PSO) is applied. Simulations are presented on a 69-bus test distribution system to verify the effectiveness of the proposed method. Results showed that the proposed high-power method to find the optimal points of problem is faster and application of DG resources reduced the losses, costs and improved the system voltage profile.[...] Read more.
Based on the power-cycle nested graph brought before, using the research methods and techniques of graph theory and combinatorial mathematics, through studying the new design idea about the basic graph,nested-cycle subgraph with gear and five-vertex sector subgraph-group, the edge-balanced index sets of the power-cycle nested graph are provided here, for and , and the proofs of the computational of formulas and the construction of the corresponding graphs also give out.[...] Read more.