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171.
An intelligent medium access control (MAC) protocol based on fuzzy logic control (FLC) is proposed and compared with a general packet radio system in UMTS (GPRS/UMTS), priority scheme and the movable boundary wireless integrated multiple access in UMTS (MBWIMA/UMTS) protocols. The integrated video/voice/data services of UMTS in UTRA TDD mode have different transmission properties. By fuzzy logic control, the resources of the wireless communication can be intelligent assigned for different types of mediums. The voice-video dropping probability and data packet delay are input to FLC to optimally select the maximum number of voice/video slots. Voice activity detector (VAD) and multiple access interference in single cell are also considered in the simulations. 相似文献
172.
We analyze a novel twolevel queueing network with blocking, consisting of N level1 parallel queues linked to M level2 parallel queues. The processing of a customer by a level1 server requires additional services that are exclusively offered by level2 servers. These level2 servers are accessed through blocking and nonblocking messages issued by level1 servers. If a blocking message is issued, the level1 server gets blocked until the message is fully processed at the level2 server. The queueing network is analyzed approximately using a decomposition method, which can be viewed as a generalization of the wellknown twonode decomposition algorithm used to analyze tandem queueing networks with blocking. Numerical tests show that the algorithm has a good accuracy. 相似文献
173.
S.A. Karamian J.S. Forster J.U. Andersen W. Assmann C. Broude J. Chevallier J.S. Geiger F. Grüner V.A. Khodyrev F. Malaguti A. Uguzzoni 《The European Physical Journal A - Hadrons and Nuclei》2003,17(1):49-56
Crystal blocking lifetime measurements have been made for highly excited Th nuclei with neutron number well removed from the
stability line. Thin W crystals were bombarded with 32S ions in the energy range 170-180 MeV and the yield of fission fragments was measured for emission close to a 〈111〉 axis.
The fission blocking dips are compared to the appropriately scaled ones for elastic scattering of the 32S beam ions and no significant difference is seen between the dips. This implies that the fraction of nuclei fissioning with
lifetimes longer than 10 as is less than 2%. Fission lifetimes are increased by viscosity in the nuclear mass flow and comparison
with a statistical model calculation indicates that the viscosity parameter, η, must be lower than for Th and U nuclei near
β-stability. The effect of the N = 126 magic number is discussed.
Received: 2 October 2002 / Accepted: 16 January 2003 / Published online: 29 April 2003 相似文献
174.
WDM网络中基于阻塞公平性的业务疏导和波长分配 总被引:2,自引:2,他引:0
在具有多速率级别连接请求的WDM网络中,通过为较高速率的请求预留更多的波长集合,结合网络节点对较低速率业务更强的输导能力,解决网络的阻塞公平性和全网的流量问题。在中国教育科研网的仿真实验,本文的策略比First-fit算法取得了更好的阻塞公平性能,并接纳了更多的网络流量。当负载为170Erlang时,多接纳的流量约为12%。 相似文献
175.
Kenneth R. Kellum 《Topology and its Applications》1980,11(3):293-296
We give a necessary and sufficient condition that a 2nd countable space be the almost continuous image of a Peano continuum. 相似文献
176.
This article discusses minimal s-fold blocking sets B in PG (n, q), q = ph, p prime, q > 661, n > 3, of size |B| > sq + c
p
q
2/3 - (s - 1) (s - 2)/2 (s > min (c
p
q
1/6, q
1/4/2)). It is shown that these s-fold blocking sets contain the disjoint union of a collection of s lines and/or Baer subplanes. To obtain these results, we extend results of Blokhuis–Storme–Szönyi on s-fold blocking sets in PG(2, q) to s-fold blocking sets having points to which a multiplicity is given. Then the results in PG(n, q), n 3, are obtained using projection arguments. The results of this article also improve results of Hamada and Helleseth on codes meeting the Griesmer bound. 相似文献
177.
Mijeong Yang Taeil Kim Haewon Jung Myoung‐Hee Jung Seung‐Hyuk Choi Min Young Chung Jaehyung Park 《ETRI Journal》2006,28(6):815-818
In the global Internet, a constraint‐based routing algorithm performs the function of selecting a routing path while satisfying some given constraints rather than selecting the shortest path based on physical topology. It is necessary for constraint‐based routing to disseminate and update link state information. The triggering policy of link state updates significantly affects the volume of update traffic and the quality of services (QoS). In this letter, we propose an adaptive triggering policy based on link‐usage statistics in order to reduce the volume of link state update traffic without deterioration of QoS. Also, we evaluate the performance of the proposed policy via simulations. 相似文献
178.
The advent of Web technology has made Web servers core elements of future communication networks. Although the amount of traffic that Web servers must handle has grown explosively during the last decade, the performance limitations and the proper tuning of Web servers are still not well understood. In this paper we present an end-to-end queueing model for the performance of Web servers, encompassing the impacts of client workload characteristics, server harware/software configuration, communication protocols, and interconnect topologies. The model has been implemented in a simulation tool, and performance predictions based on the model are shown to match very well with the performance of a Web server in a test lab environment. The simulation tool forms an excellent basis for development of a Decision Support System for the configuration tuning and sizing of Web servers. 相似文献
179.
While link allocation policies in multi-rate circuit switched loss models have drawn much attention in recent years, it is still an open question how to share the link capacity between service classes in a fair manner. In particular, when an ATM link is offered calls from service classes with/without strict QoS guarantees one is interested in link capacity sharing policies that maximize throughput and keep the per-class blocking probabilities under some GoS constraints. In this paper we propose a model and associated computational technique for an ATM transmission link to which CBR/VBR and ABR classes offer calls. We also propose a simple link allocation rule which takes into account blocking probability constraints for the CBR/VBR calls and a throughput constraint for the ABR calls and attempts to minimize the blocking probability of ABR calls. Numerical examples demonstrate the effectiveness of the policy and of the applied computational technique. 相似文献
180.