In this paper, we focus on the Hopf bifurcation control of a small-world network model with time-delay. With emphasis on the relationship between the Hopf bifurcation and the time-delay, we investigate the effect of t...
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An efficient method for simulating electromagnetic scattering from a dielectric rough surface over a frequency band is proposed. The method is based on the Chebyshev series and the Maehly approximation. The tapered pl...
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Study of polar codes in fading channels is of great importance when applying polar codes in wireless communications. Channel estimation is a fundamental step for communication to be possible in fading channels. For bo...
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In modern society, with the pad, smart phones and other wireless devices have a large number of wireless communication interface, people carry these devices that act as network nodes, the random movement of such a net...
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ISBN:
(纸本)9781538605349;9781538605332
In modern society, with the pad, smart phones and other wireless devices have a large number of wireless communication interface, people carry these devices that act as network nodes, the random movement of such a network has many characteristics of social networks. The social DTN also has many human social characteristics, such as high predictability and high similarity, so in this paper, we focus on effective routing among different regions. As for the real world, we can adjust the Spray strategy according to the regional prediction and the similarity of the encounter nodes to reduce the noneffective duplicate and decrease the consumption of networks *** results show that compared with spray and wait routing, this algorithm could not only improve the delivery rate but also significantly reduce the average latency of network.
The optimization of channel capacity in cognitive sensor networks is a complicated optimization problem. The traditional gradient search method based on the analysis has more restrictions on the objective function, an...
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ISBN:
(纸本)9781538658871
The optimization of channel capacity in cognitive sensor networks is a complicated optimization problem. The traditional gradient search method based on the analysis has more restrictions on the objective function, and high complexity, and can not determine the convergence. Aiming at the inherent problems of the traditional gradient search algorithm, the particle swarm optimization(PSO) with simple and easy to implement, distributed computing and fast convergence speed can be used to solve the problem of channel capacity optimization. It is difficult to balance the global search with the local search by adopting a standard particle swarm algorithm with fixed algorithm parameters, which can not solve the premature convergence problem that may occur. The specific meaning of each parameter of the algorithm is analyzed in this paper, and an improved particle swarm optimization algorithm based on dynamic adjustment of inertia weight acceleration factor(DWAPSO) is proposed, and the improved particle swarm optimization algorithm is applied to the optimization of channel capacity in cognitive sensor networks. The simulation results show that the improved channel capacity optimization algorithm(DWAPSO-CA) can speed up the convergence rate, increase the system capacity and get a lower bit error rate.
Delay Tolerant Network(DTN) is a network of intermittent connectivity, and for most of the time there is no end-to-end full path between nodes. This is a huge challenge for the efficient transmission of packets from t...
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ISBN:
(纸本)9781538605349;9781538605332
Delay Tolerant Network(DTN) is a network of intermittent connectivity, and for most of the time there is no end-to-end full path between nodes. This is a huge challenge for the efficient transmission of packets from the source to the destination node. In order to solve this problem, we combine the actually situation of the network, consider the difference of nodes,and propose the concept of node transmission *** a reasonable assessment of node transmission capacity and combined with the traditional probabilistic routing, this paper proposes a probabilistic routing algorithm based on the node transmission capability(PROPHET-TC), which makes the selection of the next hop node more reasonable and efficient, and compensate the deficiency of the traditional probabilistic routing in selecting the next hop node. Simulation results show that compared with Epidemic routing and probabilistic routing, the proposed algorithm can improve the delivery rate and reduce the overhead of the network.
A group activity recognition algorithm is proposed to improve the recognition accuracy in video surveillance by using complex wavelet domain based Cayley-Klein metric ***-sampled dual-tree complex wavelet packet trans...
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A group activity recognition algorithm is proposed to improve the recognition accuracy in video surveillance by using complex wavelet domain based Cayley-Klein metric ***-sampled dual-tree complex wavelet packet transform(NS-DTCWPT)is used to decompose the human images in videos into multi-scale and *** improved local binary pattern(ILBP)and an inner-distance shape context(IDSC)combined with bag-of-words model is adopted to extract the decomposed high and low frequency coefficient *** extracted coefficient features of the training samples are used to optimize Cayley-Klein metric matrix by solving a nonlinear optimization *** group activities in videos are recognized by using the method of feature extraction and Cayley-Klein metric *** results on behave video set,group activity video set,and self-built video set show that the proposed algorithm has higher recognition accuracy than the existing algorithms.
This paper presents a novel tri-band frequency miniaturized frequency selection surface (FSS). The proposed FSS consists of single-node folding and single-node folding bending. The single-layer FSS exhibits three stop...
This paper presents a novel tri-band frequency miniaturized frequency selection surface (FSS). The proposed FSS consists of single-node folding and single-node folding bending. The single-layer FSS exhibits three stop bands centered at 2.45, 3.61 and 5.79 GHz, with bandwidths of 0.42, 0.48 and 0.70 GHz, respectively. The proposed FSS has better miniaturization characteristics, and its cell size is 0.126 λ×0.126 λ. The three stop band frequencies of the FSS can be independently controlled by simply changing the length of the corresponding branch. In addition, the proposed FSS is symmetrical about the center and exhibits good resonance stability in both TE and TM polarization. The prototype of the proposed FSS was fabricated and tested, compared with the simulation results, the FSS showed stable performance. This method provides ideas for designing multiband FSS in the future.
In recent years, reversible data hiding (RDH), a new research hotspot in the field of information security, has been paid more and more attention by researchers. Most of the existing RDH schemes do not fully take it i...
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The monolayer graphene has received intensive attention due to its unique characteristics, such as atomic thickness, tunable Fermi level by doping. Here, we will present comprehensive studies from theoretical modeling...
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ISBN:
(数字)9780996007894
ISBN:
(纸本)9781728146331
The monolayer graphene has received intensive attention due to its unique characteristics, such as atomic thickness, tunable Fermi level by doping. Here, we will present comprehensive studies from theoretical modeling to application of graphene based nanodevice. Our work indicates that graphene can be considered as bulk material with an effective thickness. In addition, we propose graphene as nanospacer forming a strong coupling sandwiched nanodevice, which realizes strong coupling between localized surface plasmon of metal nanoparticle and surface plasmon of planar metal film. Our work is of critical importance for graphene modeling and applications.
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