In this paper, we propose a novel method named Contracting Community Approach (CCA) to get the maximum flow of flow network. Firstly, we contract communities in the original network. Then, we apply classic algorithms ...
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In this paper, we propose a novel method named Contracting Community Approach (CCA) to get the maximum flow of flow network. Firstly, we contract communities in the original network. Then, we apply classic algorithms on the contracted network to approximately solve the maximum flow problem. Experimental results show that the efficiency of the proposed algorithm. For sparse networks, the size of network is reduced to 58.38% averagely and the correctness of maximum flow is over 95%. For middle dense networks, the size of network is reduced to 65.77% averagely. For dense networks, the size of network is reduced to 64.84% averagely. And the correctness of maximum flow even reach 100% both in many middle dense and dense cases in our experiments.
In cognitive radio (CR) networks, unlicensed secondary users need to conduct spectrum sensing to gain access to a licensed spectrum band. And cooperation among CR users will solve the problems caused by multipath fadi...
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In cognitive radio (CR) networks, unlicensed secondary users need to conduct spectrum sensing to gain access to a licensed spectrum band. And cooperation among CR users will solve the problems caused by multipath fading and shadowing. In this paper, we propose a multi-threshold method at local nodes to cope with noises of great uncertainty. Functions of distance between bodies of evidence are used at fusion centre to make synthetic judgment. To guarantee security which is an essential component for basic network functions, we will take selfish nodes into account which try to occupy channels exclusively. The proposed technique has shown better performance than conventional algorithms without increase the system overhead.
In allusion to the phenomenon of stagnation and precocity during evolution in ant colony optimization (ACO) algorithm, this paper proposed a dual population parallel ant colony optimization (DPPACO) algorithm, which w...
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In allusion to the phenomenon of stagnation and precocity during evolution in ant colony optimization (ACO) algorithm, this paper proposed a dual population parallel ant colony optimization (DPPACO) algorithm, which was applied to the traveling salesman problem. The DPPACO algorithm separated the ants into soldier ant population and worker ant population which evolve separately by parallel method and exchanges information timely. The dynamic equilibrium between solution diversity and convergence speed is achieved by using the effect of the soldier ant's distribution to worker ants' movement choice. The DPPACO algorithm can enlarge searching range and avoid local minimum, prevent local convergence caused by misbalance of the pheromone and can improve the searching performance of the algorithm effectively. The proposed algorithm is applied in the traveling salesman problem by using the 17 data sets obtained from the TSPLIB. We compare the experimental results of the proposed DPPACO method with the traditional methods. The experimental results demonstrate that the proposed algorithm has a better global searching ability, higher convergence speed and solution diversity.
The effect of Web information extraction depends on the quality of extraction rules. But for most approaches for Web information extraction, independence of extraction rules is their common shortages. In this paper, w...
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The effect of Web information extraction depends on the quality of extraction rules. But for most approaches for Web information extraction, independence of extraction rules is their common shortages. In this paper, we propose a novel approach based on ontology for Web information extraction. We sum up four features for information items and induce these features to a group of extraction rules. Then according to a group of mapping rules between elements of ontology and extraction rules, extraction rules are well organized in ontology. According to properties of concept in ontology, the initial result of information extraction is got and then the final result is obtained by simplifying the initial results. Experiments show that our approach has higher precision.
The fast dipole method (FDM) in conjunction with the asymptotic waveform evaluation (AWE) technique is presented for fast calculation of radar cross section (RCS) from arbitrarily shaped perfect electric conductor tar...
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ISBN:
(纸本)9781467317993
The fast dipole method (FDM) in conjunction with the asymptotic waveform evaluation (AWE) technique is presented for fast calculation of radar cross section (RCS) from arbitrarily shaped perfect electric conductor targets over a broad frequency band. The FDM, which is based on the equivalent dipole-moment (EDM) method, is employed to reduce impedance matrix storage and accelerate the matrix-vector multiplications in the solutions of the Taylor coefficients. The application of AWE technique enables fast frequency sweep analysis. The numerical results show that this method greatly increased the computational efficiency without losing accuracy conditions compared with the traditional method of moments (MoM) combined with AWE technique.
An analytical solution is presented to compute the field distribution near a chiral cylinder surface at normal incidence of an on-axis Gaussian beam. The theoretical analysis of the scattering problem is complicated d...
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ISBN:
(纸本)9781467317993
An analytical solution is presented to compute the field distribution near a chiral cylinder surface at normal incidence of an on-axis Gaussian beam. The theoretical analysis of the scattering problem is complicated due to the fact that the left and right circularly polarized waves propagate in the chiral medium with different propagation constants. Numerical results for the normalized near-surface field intensity are given and discussed concisely.
The TD-SCDMA relay (repeater) provide network operators with a cost-effective means of extending coverage to areas of low signal strength. The maximum gain of a TD-SCDMA repeater is, however, limited by the amount of ...
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ISBN:
(纸本)9781467317993
The TD-SCDMA relay (repeater) provide network operators with a cost-effective means of extending coverage to areas of low signal strength. The maximum gain of a TD-SCDMA repeater is, however, limited by the amount of isolation that exists between the donor and coverage antennas. The radio echoes from coverage antennas not only create interference in the incoming signal from the base station, but also cause instability of the repeater. In this paper, we present an interference cancellation system (ICS) for TD-SCDMA networks, which can eliminate these problems. Various characteristic features of the ICS are illustrated using the MATlab.simulation results.
The conventional 'OR' fusion rule is frequently applied in two pre-determined limits energy detection networks but its overall performance of the false alarm and miss detection probability is generally. The ne...
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In this paper, Maxwell's equations are taken as a Hamiltonian system and then written as Hamiltonian canonical equations by using the functional variation method. The symplectic and ADI schemes, which can be extra...
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In this paper, Maxwell's equations are taken as a Hamiltonian system and then written as Hamiltonian canonical equations by using the functional variation method. The symplectic and ADI schemes, which can be extracted by applying two types of approximation to the time evolution operator, are explicit and implicit scheme in computational electromagnetic simulation, respectively. Since Finite-difference time-domain (FDTD) encounter low accuracy and high dispersion, the more accurate simulation methods can be derived by evaluating the curl operator in the spatial direction with kinds of high order approaches including high order staggered difference, compact finite difference and scaling function approximations. The numerical dispersion of the symplectic and ADI schemes combining with the three high order spatial difference approximations have been analyzed. It has been shown that symplectic scheme combining with compact finite difference and ADI scheme combining with scaling function performance better than other methods. Both schemes can be usefully employed for simulating and solving the large scale electromagnetic problems.
The quotient space theory based on fuzzy tolerance relation is put forward to solve the problem of clustering in this paper. The similarity matrix does not always satisfy ultrametric inequality, theoretically and prac...
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