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31.
The original BML model is extended by introducing extended sites, which can hold several vehicles at each time-step. Unexpectedly, the flow in the extended model sharply transits from free-flow to global jams, but the transition is not one-order in original BML model. And congestion in the extended model appears more easily. This can ascribe to the mixture of vehicles from different directions in one site, leading to the drop-off of the capacity of the site. Furthermore, the typical configuration of free flowing and global jams in the extended models is disorder, different from the regular structure in the original model. 相似文献
32.
In this Letter, a car-following model with consideration of roadside memorial is proposed. The numerical results show that the proposed model can qualitatively describe the impacts of roadside memorial on traffic flow and the traffic risk coefficient. It is also shown that roadside memorial can enhance the traffic safety. 相似文献
33.
The study of nonlinear diffusion equations produces a number of peculiar phenomena not present in the standard linear theory. Thus, in the sub-field of very fast diffusion it is known that the Cauchy problem can be ill-posed, either because of non-uniqueness, or because of non-existence of solutions with small data. The equations we consider take the general form ut=(D(u,ux)ux)x or its several-dimension analogue. Fast diffusion means that D→∞ at some values of the arguments, typically as u→0 or ux→0. Here, we describe two different types of non-existence phenomena. Some fast-diffusion equations with very singular D do not allow for solutions with sign changes, while other equations admit only monotone solutions, no oscillations being allowed. The examples we give for both types of anomaly are closely related. The most typical examples are vt=(vx/∣v∣)x and ut=uxx/∣ux∣. For these equations, we investigate what happens to the Cauchy problem when we take incompatible initial data and perform a standard regularization. It is shown that the limit gives rise to an initial layer where the data become admissible (positive or monotone, respectively), followed by a standard evolution for all t>0, once the obstruction has been removed. 相似文献
34.
P. G. Sarigiannidis G. I. Papadimitriou A. S. Pomportsis 《Photonic Network Communications》2006,11(2):211-227
In this paper a new packet scheduling algorithm for WDM star networks is introduced. The protocol adopted is pre-transmission
coordination-based and packet collisions have been eliminated due to predetermination of the timeslots each node transmits
in a demand matrix. The requests of the transmitted packets are predicted through Markov chains in order to reduce the calculation
time of the final scheduling matrix. This is accomplished by pipelining the schedule computation. The innovation that this
algorithm introduces is to modify the service sequence of the node. The proposed algorithm is studied via extensive simulation
results and it is proved that changing the sequence that nodes transmit, from the node with the largest number of requests
to the node with the fewest requests, that there is an increase in the throughput of the network, with a minimum (almost zero)
cost in mean time delay and in delay variance. 相似文献
35.
赵颖 《信息安全与通信保密》2006,(7):71-72
实施建立一套较好的登录控制机制,能够为用户提供统一的信息资源认证访问入口,建立统一的、基于角色和个性化的信息访问、集成平台。通过实施单点登录功能,使用户只需一次登录就可以根据相关的规则去访问不同的应用系统,提高信息系统的易用性、安全性、稳定性,并在此基础上进一步实现政府、企业用户高速协同办公。 相似文献
36.
ATM网络中突发业务的漏桶算法分析 总被引:11,自引:0,他引:11
统计复用可以使突发业务获得较高的频带利用率,但必须对输入的业务量进行恰当的控制,否则会造成严重的网络拥塞,漏桶法是ATM网络基于速率调节进行业务量控制的一种重要的方法,本文对突发业务的漏桶算法进行了分析,得出了突发业务的漏桶性能与输入业务统计参数和漏桶参数之间关系的解析式,计算机模拟结果表明它与理论分析的一致性。 相似文献
37.
形态骨架匹配算法及其在交通标志识别中的应用 总被引:1,自引:0,他引:1
交通标志是人为的、具有特殊形状的符号,就其结构可分为外层轮廓和内核两部分。应用计算机视觉可以对交通标志进行自动识别.其关健在于如何检测交通标志和识别它们的内核形状。本文应用数学形态学方法研究交通标志内核形状的形态特征,分析了内核形状的形态骨架,提出和讨论了内核形态骨架的相关函数和距离函数,并就交通标志的有效识别提供了理论分析和实验结果。 相似文献
38.
In this paper the author writes a simple characterization for the best copositive approximation in c; the space of convergent sequences, by elements of finite dimensional Chebyshev subspaces, and shows that it is unique. 相似文献
39.
Optical channels are currently able to carry 10 Gbit/s and even 40 Gbit/s traffic flows. However, it is not usual to have
such amounts of traffic between any pair of client nodes. This article proposes using point-to-multipoint optical channels
for the allocation of point-to-point connections in transparent wavelength-routed optical networks. Specifically, when an
optical connection between a source-destination node pair has to be established, the optical signal is also sent to some adjacent
nodes by introducing passive optical splitters; in this way a light-tree is built. Then, the already established point-to-multipoint
optical channel can be used to groom further point-to-point connections between the same source node and each of the other
nodes composing the light-tree. The benefits of this strategy are 2-fold: first, the reduction of optical transmission equipments
allowing cost savings with respect to the traditional typical point-to-point approach and, second, the optimization of the
optical channels utilization meeting in such a way Traffic Engineering objectives. The merits of proposed approach are evaluated
by simulation. 相似文献
40.
Long-range dependence, short-range dependence and marginal distribution are three key statistical features for incoming traffic, which have a serious impact on network performance. This paper respectively, studies their characteristics during traffic shaping at the edge node in synchronous optical packet-switched networks and highlights the functions of the First-Come-First- Service (FCFS) schedule queue for various offered loads and assembly parameters, including normalized timeout and normalized threshold. Simulation results demonstrate that under light-medium load the FCFS schedule queue works as a low pass filter, i.e., the statistical features before and after the FCFS schedule queue is nearly the same and each of the statistical features approximately follows the same trend. Heavy load drives the FCFS schedule queue into an overload or saturation state and the three statistical features all exhibit different behavior. By adjusting the assembly parameters, the deficiency can be modified. 相似文献