ASON动态光通路建立的阻塞分析

光路阻塞率是智能光网络性能重要的度量指标之一.文章对影响自动交换光网络(ASON)阻塞率的因素进行了综述,对其中的两个因素:资源保留方式和波长变换器(WC)配置方式作了重点介绍.文章还应用曾用于电路交换网的基于通路图和Lee氏的计算方法近似地对阻塞率进行了计算.     

不平衡业务下CDMA蜂窝系统的呼叫接入控制方案

针对 CDMA蜂窝系统区间业务不平衡的情况 ,文中提出了一种呼叫接入控制方案 ,在重负荷小区为邻区即将到来的呼叫预留部分资源 ,预留的大小随呼叫阻塞情况自适应地调整。仿真结果显示 :该方案能很好地解决区间业务不平衡的问题 ,而且与基于固定资源预留的呼叫接入控制方案相比 ,还能获得低的系统呼叫阻塞率     

大规模通信网络带宽分配的快速分解优化

本文对大规模通信网络带宽分配的计算过程进行了研究，发现现有分解优化计算的方法中限制计算速度的瓶颈在于主节点上的等效流量的计算，在此基础上提出一种用近似公式代替递推公式计算呼叫损失概率的方法，将它运用于带宽分配算法中，计算速度大力提高，而计算相对误差为10％左右。     

Approximate analysis of arbitrary configurations of open queueing networks with blocking

An algorithm for analyzing approximately open exponential queueing networks with blocking is presented. The algorithm decomposes a queueing network with blocking into individual queues with revised capacity, and revised arrival and service processes. These individual queues are then analyzed in isolation. Numerical experience with this algorithm is reported for three-node and four-node queueing networks. The approximate results obtained were compared against exact numerical data, and they seem to have an acceptable error level.Supported in part by a grant from CAIP Center, Rutgers University.Supported in part by the National Science Foundation under Grant DCR-85-02540.     

A Bose‐Burton type theorem for quadrics

Let Q be a non‐degenerate quadric defined by a quadratic form in the finite projective space PG(d,q). Let r be the dimension of the generators of Q. For all k with 2 ≤ k < r we determine the smallest cardinality of a set B of points with the property that every subspace of dimension k that is contained in Q meets B. It turns out that the smallest examples consist of the non‐singular points of quadrics S ∩ Q for suitable subspaces S of codimension k of PG(d,q). For k = 1, the same result was known before. © 2003 Wiley Periodicals, Inc. J Combin Designs 11: 317–338, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/jcd.10051     

Blocking Probabilities in Mobile Communications Networks with Time-Varying Rates and Redialing Subscribers

Call-blocking probabilities are among the key performance measures in mobile communications networks. For their analysis, mobile networks can be modelled as networks of Erlang loss queues with common capacity restrictions dictated by the allocation of frequencies to the cells of the network. However, due to the time-varying load offered to the cells of such networks, blocking probabilities usually cannot be obtained in closed form. The relation between networks of Erlang loss queues and networks of infinite server queues, for which the time-dependent occupancy distribution is multidimensional Poisson, suggests to use that distribution as approximate distribution for the network of Erlang loss queues. This paper extends this so-called Modified Offered Load (MOL) approximation to networks of Erlang loss queues, and also allows subscribers that find their call blocked to redial to continue their call. For GSM networks operating under Fixed Channel Allocation, it is shown that blocking probabilities are increasing in the redial rates so that the MOL approximation that is most accurate for maximal redial rates turns out to be fairly accurate for the resulting upper bound for blocking probabilities. The accuracy is explicitly evaluated in an application of the results towards blocking probabilities in a hot spot travelling along a road through a GSM network.     

72172Hf和72174Hf高K多准粒子低激发带的粒子数守恒计算

用处理推转壳模型的粒子数守恒(PNC)方法,分析了稀土变形核^172,174Hf的基态带和低激发高K多准粒子带的运动学转动惯量J⁽¹⁾随角频率ω的变化及其微观机制,特别是被拆散核子的Pauli堵塞效应的重要影响.实验观测到的J⁽¹⁾和顺排角动量随角频率的变化在PNC计算中得到较好的重现.计算中无自由参数.分析表明,高K多准粒子带的J⁽¹⁾随ω的变化与基态带不同,主要来自高N(j)闯入态的堵塞效应.     

Synthesis of Methyl-2, 3-Di-O-Methyl 6-Deoxy-3-C-Methyl-a-D-Gulopyranoside

Methyl 2,2-di-O-methyl-6-C-methyl-α-D-gulopyranoside has been synthesized from D-glucose. The introduction of methyl branching at 3-position was achieved by the Grignard reaction.     

带有肖特基漏极和场板结构的反向阻断垂直MOSFET研究

提出了一种采用肖特基漏极(SD)与场板相结合、实现硅基垂直MOSFET器件反向阻断应用的技术。基于该技术,采用二维仿真提出并研究了两种新型垂直MOSFET器件,即带有垂直场板(VFP)的SD-VFP-MOS器件和带有倾斜场板(SFP)的SD-SFP-MOS器件。相比采用肖特基漏极的MOSFET (SD-MOS)和采用超结和肖特基漏极的MOSFET(SD-SJ-MOS),所提出的SD-VFP-MOS,尤其是SD-SFP-MOS,反向击穿电压有显著提高,且几乎不影响导通特性。开展了器件的开态电流密度、关态电势分布、关态电流密度和电场分布分析,揭示了VFP和SFP提高器件反向阻断能力的内在机理。详细讨论了场板结构参数对器件反向击穿电压和场板效率的影响,研究结果对于SD-VFP-MOS和SD-SFP-MOS的设计具有重要意义。