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41.
In this research paper, we propose a two-hop integrated radio frequency–visible light communication (RF–VLC) system which may provide a better option to transceive between the hospitals and some laboratory to transfer patient’s information. In the proposed system model, the data (such as patient’s lab test reports) is transmitted towards the amplify and forward (AF) relay mounted on the top of the hospital building via the RF channel. Further, the AF relay amplifies and converts the received information into corresponding optical signal using light emitting diodes (LED) and supporting circuitry. This optical signal is then forwarded towards the destination device (equipped with VLC transceiver), via the VLC channel. To analyse the performance of the system, we first derive the closed form analytical expressions for the cumulative distribution function (CDF) of the end-to-end (e2e) signal to noise ratio (SNR) of the system by using the moment generating function (MGF) of the SNR of the individual RF and VLC channels. Further, we use these statistical expressions to obtain the outage probability, average bit error rate (BER) and the average capacity of the system. Moreover, the asymptotic performance of the proposed system is also analysed to study the system’s behaviour at high SNR regimes. Finally, we studied the impact of the variations in channel parameters on the proposed system model performance through numerically simulated plots. 相似文献
42.
43.
Han-xing Wang Xi Hu Qin Zhang 《应用数学学报(英文版)》2007,23(2):235-244
In this paper,we present a random graph model with spatial reuse for a mobile ad hoc network(MANET) based on the dynamic source routing protocol.Many important performance parameters of theMANET are obtained,such as the average flooding distance (AFD),the probability generating function of theflooding distance,and the probability of a flooding route to be symmetric.Compared with the random graphmodel without spatial reuse,this model is much more effective because it has a smaller value of AFD and alarger probability for finding a symmetric valid route. 相似文献
44.
By Petersen's theorem, a bridgeless cubic multigraph has a 2-factor. Fleischner generalised this result to bridgeless multigraphs of minimum degree at least three by showing that every such multigraph has a spanning even subgraph. Our main result is that every bridgeless simple graph with minimum degree at least three has a spanning even subgraph in which every component has at least four vertices. We deduce that if G is a simple bridgeless graph with n vertices and minimum degree at least three, then its line graph has a 2-factor with at most max{1,(3n-4)/10} components. This upper bound is best possible. 相似文献
45.
46.
Single line queue with repeated demands 总被引:2,自引:0,他引:2
K. Farahmand 《Queueing Systems》1990,6(1):223-228
We analyze a model of a queueing system in which customers can only call in to request service: if the server is free, the
customer enters service immediately, but if the service system is occupied, the unsatisfied customer must break contact and
reinitiate his request later. Such a customer is said to be in “orbit”. In this paper we consider three models characterized
by the discipline governing the order of re-request of service from orbit. First, all customers in orbit can reapply, but
are discouraged and reduce their rate of demand as more customers join the orbit. Secondly, the FCFS discipline operates for
the unsatisfied customers in orbit. Finally, the LCFS discipline governs the customers in orbit and the server takes an exponentially
distributed vacation after each service is completed. We calculate several characteristics quantities of such systems, assuming
a general service-time distribution and different exponential distributions for the times between arrivals of first and repeat
requests. 相似文献
47.
Robert J. Rubin 《Journal of statistical physics》1991,65(5-6):1207-1216
A one-dimensional lattice random walk in the presence ofm equally spaced traps is considered. The step length distribution is a symmetric exponential. An explicit analytic expression is obtained for the probability that the random walk will be trapped at thejth trapping site. 相似文献
48.
Exact closed-form solutions are exhibited for the Hopf equation for stationary incompressible 3D Navier-Stokes flow, for the cases of homogeneous forced flow (including a solution with depleted nonlinearity) and inhomogeneous flow with arbitrary boundary conditions. This provides an exact method for computing two- and higher-point moments, given the mean flow. 相似文献
49.
本文针对汽车保险中多车辆相撞事故的理赔建立起广义泊松过程模型,利用概率母泛函给出了其理赔总量在(0,t]内的均值与方差,并基于鞅分析方法证明了其破产概率的Lundberg不等式. 相似文献
50.