We investigate the average Level Crossing Rate (LCR) and Average Fading Duration (AFD) of multiuser single relay co- operation wireless uplinks over independent and non-identically distributed (***.d) Ray- leigh...
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We investigate the average Level Crossing Rate (LCR) and Average Fading Duration (AFD) of multiuser single relay co- operation wireless uplinks over independent and non-identically distributed (***.d) Ray- leigh fading channels. We first present the statistical analyses of the first-hop equivalent envelope. Then, we investigate the LCR and AFD of an equivalent end-to-end envelope, and present the closed-form solutions to LCR and AFD, which are given with integral forms. Finally, we derive the Laplace approximations of LCR and AFD as well as the upper and lower bounds. The numerical results of LCR show that the upper bound is tight. For multi user systems with different number of mobile users, the analyses indicate that the LCRs are approximately the same at the low level of the envelope. envelope However, there are at the high level of the reasonable differences among the curves of LCRs. Due to that fact that AFD is the inverse function of LCR, the results for AFD are the opposite.
In this paper, we propose a robust object tracking algorithm based on SURF. First, we adopt a two-stage matching method to improve the accuracy of SURF matching points. Then a template update method is used to deal wi...
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In this paper, we propose a robust object tracking algorithm based on SURF. First, we adopt a two-stage matching method to improve the accuracy of SURF matching points. Then a template update method is used to deal with the problem of object appearance change. Next we use matching points between new template and candidate region to locate the initial position of object. As template update and object occlusion will cause the accumulation of tracking errors, therefore, at last fixed template is used to correct object's position. For those frames which have little matching points, we use Meanshift instead of SURF to track object. The experiments demonstrate that our work is robust and can track object accurately in complex environments.
Proxy re-signature is proposed by Blaze, Blemmer and Strauss (BBS), in which a semi-trusted proxy acts as a translator converts a signature from Alice into a signature from Bob on the same message. Proxy re-signature ...
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Proxy re-signature is proposed by Blaze, Blemmer and Strauss (BBS), in which a semi-trusted proxy acts as a translator converts a signature from Alice into a signature from Bob on the same message. Proxy re-signature is a very useful tool for the interoperable DRM architecture and the proof of passed path in cloud computing. However, cloud users usually are mobile devices which are constrained with processing and power limitations. When a mobile user obtain the converted signature from the proxy (cloud server), it still can not verify it due to the heavy computation cost. We propose a new definition of server-aided verification proxy re-signature which consist of a proxy re-signature scheme and a server-aided verification protocol. With the server-aided verification protocol, some computational tasks for a proxy re-signature verification are carried out by the proxy (cloud server), which is generally untrusted, therefore, it is very useful for mobile devices. We present, on the basis of Ateniese and Hohenberger's unidirectional proxy re-signature scheme, two novel existential unforgeability server-aided verification proxy re-signature schemes.
P-homomorphic signature is a general framework for computing on authenticated data, which is recently proposed by Ahn et al. With P-homomorphic signature, any third party can derive a signature on the object message m...
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Stream data is a very common data type in big data and in many data streams applications,users tend to pay more attention to the mode information of the data *** mining frequent patterns in data streams is a significa...
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ISBN:
(纸本)9781479900763
Stream data is a very common data type in big data and in many data streams applications,users tend to pay more attention to the mode information of the data *** mining frequent patterns in data streams is a significative ***,finding frequent itemests in a data set with predefined fixed support threshold could be seen as an optimization *** this paper,the problem of frequent itemsets mining is derived as a non-linear optimization problem,then genetic algorithm is adopted to solve *** the formal and bitmap representation of frequent itemsets,the non-linear optimization problem is transformed to 0-1 programming.A set of experimental results show that unlike typical Apriori algorithm,the complexity of time and memory space grows exponentially as the support decrease,our proposed algorithm has a high time and space efficiency even with a very low support.
network virtualization,as a fundamental technology of Future Internet Architecture,has been used to overcome the ossification of the current *** paper focuses on virtual nodes splitting for aggregating the diverse phy...
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network virtualization,as a fundamental technology of Future Internet Architecture,has been used to overcome the ossification of the current *** paper focuses on virtual nodes splitting for aggregating the diverse physical resources in the issue of virtual network embedding(VNE),which is used for the resource allocation in network virtualization.A mixed integer programming(MIP) problem has been proposed by taking both path-splitting and node-splitting into *** feasibility of virtual node splitting is analyzed and a corresponding formal expression is *** VNE performance is evaluated using by a generic MIP solver over a NSFNET *** numerical evaluations in this paper show that,comparing with the approaches for VNE without node-splitting,the proposed algorithm is beneficial to reduce VNE cost,as well as to increase VN acceptance ratio.
According to the significant impact on the accuracy rate of detection of current immune algorithms brought by incorrect classification of signal, it proposes network malicious code dendritic cell immune algorithm base...
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In this paper, we proposed a three-step frequency offset estimation method using a special training frame designed for cable channel in OFDM systems. By making use of the PN-sequence preambles of the training frame, t...
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In this paper, we proposed a three-step frequency offset estimation method using a special training frame designed for cable channel in OFDM systems. By making use of the PN-sequence preambles of the training frame, the coarse frequency offset estimation is achieved by the two initial steps. In order to estimate fine frequency offset, we utilize quartic method to eliminate the influence of modulation on the payload data of the training frame. By configuring the three-step estimation neatly, the proposed method makes it possible to realize large span of frequency offset estimation even to half of the system bandwidth, and has high estimation precision. Simulations in AWGN and multipath channels proved the validity of this technique.
Cooperative Spectrum Sensing (CSS) is well known that, in the fading environment, it can effectively improve the spectrum sensing performance. However, a common problem in CSS requires that the communication links bet...
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