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11.
Existing Ethernet Passive Optical Network (EPON) Dynamic Bandwidth Allocation (DBA) algorithms suffer from the disadvantage of idle time loss,which lower the upstream bandwidth utilization.This letter ... 相似文献
12.
电厂实际燃煤的煤质成分与原设计值偏差较大,通过增设DBA脱硫增效系统,使原脱硫设计系统适应实际这种高硫份煤的要求. 相似文献
13.
In this paper, we analyze the mean packet delay of a dynamic bandwidth allocation (DBA) scheme in an Ethernet passive optical
network (EPON). We propose the interleaved polling system with a gated service discipline and a two-stage queue in order to
investigate the delay performance of DBA scheme in an EPON. We assume that input packets arrive at an optical network unit
(ONU) according to a Poisson process from several types of users. We use a continuous time queueing model in order to find
the mean packet delay and the mean cycle time of an arbitrary packet. We obtain the closed form solution for the mean packet
delay of the proposed gated polling system with a two-stage queue. We obtain another result on the mean packet delay by solving
a system of linear equations derived from the moments of the queue length distribution. We give some numerical results to
investigate the delay performances for the symmetric polling system with statistically identical stations. In addition, we
compare numerical results on the closed form solution with numerical results on a system of linear equations. 相似文献
14.
参照ITU T建议草案:吉比特无源光网络传输汇聚层规范(G.GPON.gtc),提出了一种支持分组业务接入的媒质接入控制(MAC)协议.通过仿真建模对该协议的性能进行了分析. 相似文献
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16.
Pursuant to the Energy Policy Act of 2005, the High Temperature Gas-Cooled Reactor (HTGR) has been selected as the reference design for the Next Generation Nuclear Plant (NGNP). Stemming from a U.S. Nuclear Regulatory Commission (NRC) HTGR research initiative, a need was identified for validation of systems-level computer code modeling capabilities in anticipation of the eventual need to perform licensing analyses. Because the NRC has used MELCOR for light water reactors (LWR) in the past and because MELCOR was recently updated to include gas-cooled reactor (GCR) physics models, MELCOR is among the system codes of interest to the NRC. This paper describes MELCOR modeling of the General Atomics' Modular High Temperature Gas-Cooled Reactor (MHTGR). The MHGTR is a suitable design for demonstration of MELCOR GCR modeling competency for two reasons: 1) the MHTGR is a predecessor to the more advanced General Atomics’ Gas-Turbine Modular High Temperature Reactor (GTMHR), and 2) experimental data useful for benchmark calculations may soon become available. Using the most complete literature references available for the MHTGR design, researchers at Texas A&M University (TAMU) constructed a MELCOR input deck for the MHTGR to partially validate MELCOR GCR modeling capabilities. Normal and off-normal system operating conditions were modeled with appropriate boundary and initial conditions. MELCOR predictions of system response were obtained for steady-state, pressurized conduction cool-down (PCC), and depressurized conduction cool-down (DCC) scenarios. Code results were checked against nominal MHTGR design parameters, physical intuition, and anticipated GCR thermal hydraulic response. No inherent deficiencies in MELCOR modeling capability were observed, suggesting that the newly-implemented GCR models are adequate for systems-level analysis. If and when experimental benchmark data becomes available, further validation activities may proceed given the modeling efforts discussed herein. 相似文献
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18.
In this paper, we overview the principle of Orthogonal Frequency Division Multiplexing Passive Optical Network (OFDM-PON) systems, with a particular focus on upstream architectures capable of achieving 10Gbit/s colorless upstream transmission using Reflective Semiconductor Optical Amplifier (RSOA). We propose an architecture of RSOA based OFDM-PON which can achieve 10Gbit/s upstream transmission over a single wavelength. A novel Dynamic Subcarrier Assignment (DSA) algorithm is also proposed to support my architecture, namely Service based Polling in Pipeline (SPP) dynamic subcarrier algorithm. A simulation was conducted to study the performance of SPP algorithm. Compared with the traditional dynamic bandwidth allocation algorithms, service based polling meets the quality of in pipeline algorithm service requirements excellently, and adapts orthogonal frequency division multiplexing passive optical network better with higher bandwidth efficiency and lower algorithm complexity. 相似文献
19.
提出一种新的基于国际标准和区分服务(Differentiated Service)的以太无源光网络(EPON)动态带宽分配(dynamic bandwidth allocation,DBA)方案,该方案不仅能够在上行方向为多个光网络单元(Optical Network Unit,ONU)高效并公平地分配有限的带宽,而且能够最大限度地保证不同ONU间及不同通信等级间的公平性以及高等级通信的服务质量(QoS)要求.仿真结果证明,与现有算法相比,本算法在延时和利用率方面均有改进,在重负荷情况下改进更明显. 相似文献
20.
传统的EPON系统的上行带宽分配方案是类似于IPACT的基于时隙长度分配的,这样虽然使上行信道得到了充分的利用,但是由于包延迟变化较大,不适合实时业务的传送.介绍了一种混合时隙长度/速率DBA方案,它可以为不同业务提供不同的QoS,既满足了实时业务的需要,又在一定程度上提升了网络的利用率. 相似文献