输入排队结构交换机分组调度研究

以决定分组调度算法的交换结构为基础,从协调,减少和隔离输入排队交换结构中输入输出竞争裁决冲突的角度,分别讨论了VOQ,CIOQ,CICQ结构中的分组调度问题,并以当前最新的调度算法为例加以说明,进行了定性分析和定量对比,指出了具体有待研究的问题。随后讨论了最近才开始研究的光电混合结构中的分组调度问题。最后从交换结构和算法两个方面探讨了今后的研究方向和发展趋势。     

零电压开关温度/功率控制器UAA1016/UAA2016及其应用

UAA1016／UAA2016是采用零电压技术设计的、可驱动双向可控硅的温度／功率控制器集成电路，通过该芯片可实现电阻性负载的无RFI功率调节。文中介绍了UAA1016／UAA2016的主要特点、基本原理及应用电路。     

基于复合型单开关PFC预调节器的设计

为了解决计算机系统电源保持时间问题,确保输出电压在一段时间稳定在一定范围内。确保计算机在出现输入故障是有足够的时间备份数据或者切换到不间断电源(UPS)下工作。为此提出了一种复合型单开关PFC预调器、并根据需求进行了设计,该设计可以减小储能电容的容量,使输出电流谐波满足IEC1000-302的要求。     

Optical time-domain reflectometry for distributed sensing of the structural strain and deformation

A unique structure of microbend optical fiber sensor (MOFS) for measuring tensile and compressive strain is described in this paper. The average measuring sensitivity for tensile strain is 35μ using 3 MOFS arrays. The repeatability and stability of MFOS are better than 18μ. The loss sensitivity of single-mode (SM) fiber and multi-mode (MM) fiber used in MOFS, as well as the relationship between the pulse width of diode laser and loss sensitivity are also studied in this paper. From these studies, some conclusions have been obtained. They are (1) the loss sensitivity and repeatability of SM fiber are better when compared to MM fiber in MOFS, and (2) the variation of pulse width of laser would only influent the signal-to-noise ratio and dynamic range, but has no contribution to loss sensitivity. Experimental results also show that loss of SM fiber highly depends on the wavelength of laser, but MM fiber has no such property. The loss of SM fiber between the wavelength of 1550 and 1310 nm is about the ratio of 6.5. Therefore, the experiments reported in this paper used a wavelength of 1310 nm to measure tensile strain and 1550 nm to measure compressive strain based on the above property of SM fiber, without changing the configuration of MOFS.     

下一代多媒体网络框架研究

文章分析了NGN的分层结构,结合现存网络体系给出一种完整的NGN多媒体通信框架方案,解决了在NGN上实现多媒体业务的有关技术问题.最后,指出了NGN有待于解决的若干问题以及下一步的主要工作.     

一种高抑制带通滤波器频选组件的研制

介绍了一种低频段高抑制频选组件的设计方法和试验结果。该频选组件由多个带通滤波器、开关组件、转换开关、远控电路组成。测试结果表明在-20℃-＋55℃温度范围内带通滤波器的高端阻带衰减≥84dB；低端阻带衰减≥74dB。     

有机聚合物BPDA-ODA-DR1的合成及热光性能的研究

用3,3’,4,4’-联苯四甲酸二酐(BPDA)、4,4’-二胺基二苯醚(4,4’-ODA)和分散红1(DR1)合成了可制作光波导器件的聚酰亚胺(PI)有机聚合物,采用示差扫描量热(DSC)、热失重分析(TGA)和紫外吸收光谱等方法对其热稳定性和光学性质进行了表征。DSC和TGA结果显示,该PI的玻璃化转变温度(Tg)为248℃,在5%的热失重温度为285℃,表明具有非常好的热稳定性。演示了用阿贝折射仪测定该材料的折射率(n)和热光系数(dn/dT)的方法;通过改变PI含量的方法,方便地实现了聚合物体系的折射率控制;通过热光系数的测量,计算了聚合物的介电常数(ε)、介电热光系数(dε/dT)和体积热膨胀系数β及其变化率(dβ/dT)。制得的聚合物材料的dn/dT为-2.2615~-3.7028×10-4K-1,dβ/dT为2.22~6.14×10-7K-1,表明该聚合物在低驱动功率的新型数字热光开关、光通信器件等领域具有潜在的应用前景。     

使用多级交换网络进行大容量光纤通道交换机设计

介绍了三级Clos网络拓扑,在此基础上设计了基于Clos网络的大容量光纤通道交换机体系结构.针对三级Clos网络存在的信元调度和路由分配问题,提出了一种新颖的采用流水线并行处理方式的双重匹配帧调度策略.该设计和策略对大容量光纤通道交换机的研制具有一定参考意义.     

分子尺寸器件与单分子器件

未来的计算机可以小到什么程度?迄今无人可以做详尽的回答。但毫无疑问,硅基集成电路由于光刻技术的限制和生产成本随尺寸变小作指数增长,将很快达到它的极限(最小线宽100nm)。目前国际上已提出未来的纳米电子器件的各种方案,其中最小的器件有可能由单个分子所构成。扼要讨论了当前最“热门”的分子尺寸电子器件以及将要进一步发展的单分子电子器件。其中具有电双稳性能的分子是最可期许的材料。初步的研究结果表明能得到构成逻辑门用的单分子开关、超高密度存贮器和单分子整流器等功能器件的原型。最后还讨论了分子电子学进一步发展的前景和问题。     

Discrete-time analysis of a classified multi-server queue with burst arrivals and a shared buffer

We study a discrete-time, classified multi-server queue with a shared buffer. There arem servers and each server belongs to one ofk classes (mk), so thatk kinds of jobs can be served in the system. We characterize a bursty arrival process using bursts which consist of the same kind of jobs. Once the first job of a burst arrives at the queue, the successive jobs will arrive on every time slot until the last job of the burst arrives. The numbers of jobs of a burst and the inter-arrival times of bursts are assumed to be i.i.d., respectively, and the service time is assumed to be equal to one slot. We propose an efficient numerical method to exactly obtain the job loss probability, the waiting time distribution and the mean queue length. We apply this model to the ATM switch with a shared buffer and obtain the performance measures. Numerical results show the advantage of the ATM switch with a shared buffer compared to the one with output buffers.