OPTIMIZATION OF WDM OPTICAL PACKET SWITCHES WITH SPARSE WAVELENGTH CONVERTERS AND NON-DEGENERATE FIBER DELAY-LINES

This paper investigates the untraditional approach of contention resolution in Wavelength Division Multiplexing (WDM) Optical Packet Switching (OPS). The most striking characteristics of the developed switch architecture are: (1) Contention resolution is achieved by a combined sharing of Fiber Delay-Lines (FDLs) and Tunable Optical Wavelength Converters (TOWCs); (2) FDLs are arranged in non-degenerate form, i.e., non-uniform distribution of the delay lines; (3) TOWCs just can perform wavelength conversion in partial continuous wavelength channels, i.e., sparse wavelength conversion. The concrete configurations of FDLs and TOWCs are described and analyzed under non-bursty and bursty traffic scenarios. Simulation results demonstrate that for a prefixed packet loss probability constraint, e.g., 10-6, the developed architecture provides a different point of view in OPS design. That is, combined sharing of FDLs and TOWCs can, effectively, obtain a good tradeoff between the switch size and the cost, and TOWCs which are achieved in sparse form can also decrease the implementing complexity.     

模块化片上系统中高级可扩展接口的死锁避免

模块化片上系统(MSoC)包含多个独立的IP组件及多个可能的子网络,这种异构集成的方式往往为片上网络(NoC)引入潜在的死锁。该文基于模块化异构系统MSoC研究了使用高级可扩展接口(AXI)协议的片上网络中3种类型的死锁。MSoC包含多种常见的异构组件,以及由多个独立子网络集成的片上网络,能够充分反映真实芯片的复杂性和不规则性。该文发现除环形通道导致的死锁外,基于AXI的片上网络还涉及双重路径死锁和桥接死锁。该文还提出一种两阶段算法检测片上网络中可能存在的这3种死锁。相比于通用验证方法学(UVM)随机验证,使用该算法可以将检测时长从几个月缩短到几个小时,提高片上网络的可靠性和鲁棒性。     

The combined effect of hypertension and type 2 diabetes mellitus on aortic stiffness and endothelial dysfunction: An integrated study with high-resolution MRI

Purpose

The purpose of this study was to investigate the combined effect of hypertension and type 2 diabetes mellitus (DM2) on aortic stiffness and endothelial dysfunction by using an integrated MRI approach.

Materials and Methods

A total of 31 non-hypertensive DM2 patients and 31 hypertensive DM2 patients underwent 3.0-T MRI. Aortic distensibility (AD), pulse wave velocity (PWV) and brachial artery flow-mediated dilation (FMD) were assessed. Student's t-test, Mann–Whitney U test, chi-squared test, Pearson correlation analysis, and univariable and multiple linear regression analyses were used for statistical analyses.

Results

The hypertensive patients showed lower AD at multiple levels (ascending aorta [AA]: 2.07 ± 0.98 × 10^− 3 mm Hg^− 1 vs. 3.21 ± 1.70 × 10^− 3 mm Hg^− 1, p < 0.01; proximal thoracic descending aorta [PDA]: 2.58 ± 0.72 × 10^− 3 mm Hg^− 1 vs. 3.58 ± 1.47 × 10^− 3 mm Hg^− 1, p < 0.01; distal descending aorta [DDA]: 3.11 ± 1.84 × 10^− 3 mm Hg^− 1 vs. 4.27 ± 1.75 × 10^− 3 mm Hg^− 1, p < 0.01); faster PWV (7.46 ± 2.28 m/s vs. 5.82 ± 1.12 m/s, p < 0.05) and lower FMD (12.67% ± 6.49% vs. 20.66% ± 9.7%; p < 0.01). Systolic blood pressure was an independent predictor of PWV, AA-AD, DDA-AD and FMD. FMD was statistically significantly associated with PWV (r = − 0.37, p < 0.01) and AD (p < 0.01).

Conclusions

Hypertension has a contributive effect on aortic stiffness and endothelial dysfunction in DM2 patients.     

基于EPON/GPON的FTTH接入网OAM研究

本文结合国内ADSL宽带接入网运维的实际情况和国外FTTH网络运维方面的成功经验,根据中国电信FTTH现场试验取得的一些成果,面向将来大规模建设FTTH接入网的实际需要和运维技术的发展趋势,系统地分析了FTTH网络运行维护的内容和特点、维护体制与流程、维护手段和方法.     

TDM over GPON技术研究

首先介绍了在吉比特无源光网络(GPON)上实现TDM承载的方案及其基本原理,然后对几种方案做了简单的比较,最后总结了GPON承载TDM业务时与现有网络的连接方案.     

带内多波长光标记分组交换技术的研究

介绍了一种带内多波长光标记分组交换技术。在这种光交换中,光信头由若干个与光载荷处于同一通信信道内的具有不同波长值的光脉冲构成。探讨了包括信头产生和光分组形成部分的光发射机技术,包括数据恢复的接收机技术和包括路由处理的光交换节点技术。一个简化的实验演示了这种光交换的原理。     

干涉法测量掺铒光纤的非线性折射率

本文提出一种测量掺铒光纤非线性折射率的方法,该方法使氩离子激光通过一根掺铒光纤和另一根并排的普通光纤产生干涉.由掺铒光纤的非线性折射率导致的位相差变化将使干涉条纹发生位移,通过位移的测量可以得出光纤的非线性折射率.     

凯泽-贝塞耳窗在傅里叶变换轮廓技术中的应用

在傅里叶测量轮廓术中,由于连续傅里叶变换的离散化,即采用的是离散傅里叶变换,必然会产生漏频和混频等效应,从而对相位的求解造成较大误差,本文着重讨论了漏频的情况,通过理论分析及计算机模拟得到:用凯泽-贝塞耳加权可更有效的减小漏频引起的误差.