光传输网规划中光缆芯数及光纤类型确定的影响因素

光传输网是电信网的基础,由于光缆线路系统的特殊性,决定了光传输网规划中光缆芯数及光纤类型的确定尤其重要。     

On Reversible Skeletonization Using Anchor-Points from Distance Transforms

In many applications thinning of objects is of great interest. We here present a skeletonization algorithm that is based on the idea of iteratively thinning the distance transform of an object layer by layer until either an anchor-point is reached or the connectivity breaks. Our algorithm is general in the sense that any metric and any connectivity can be used. Also, it is based on ideas that are not specific for 2D. The properties of the resulting skeletons are evaluated according to the “Lee–Lam–Suen properties.”     

IPSec抗重放功能对网络QoS的影响研究

论文简单介绍了IPSec安全设备及抗重放功能,并针对网络中部署IPSec安全设备并启用抗重放功能的情况,分析了如果设备的参数没有充分考虑业务QoS需求与安全需求的相互配合,就可能对QoS产生影响的原因,提出了通过调整IPSec安全设备配置参数的解决方法,满足了网络的安全和QoS的要求。     

用未确知有理数确定指标主观权重方法研究

指标权重的合理确定对多指标综合评价至关重要。为了进一步提高指标主观赋权的科学性和合理性,文章提出了应用未确知有理数确定评价指标主观权重的新方法,阐述了其基本思想和求解步骤。应用实例表明,该指标主观赋权法计算简单,结论可靠,具有一定的实际应用价值。     

分簇无线传感器网络基于随机数的两级身份认证

文中提出一种分簇无线传感器网络的基于随机数的两级身份认证方法。该方案将认证过程分为两个阶段：簇头与基站的一级认证和成员节点与基站的二级认证。整个认证过程采用对称加密的方法,通过检查随机数的一致性来保证认证过程的连贯,对存储开销的要求较低。簇头作为中转节点,在全网中具有重要作用。在保证簇头安全的前提下成员节点才与基站开始认证,这样能有效地避免成员节点与基站在簇头不安全的情况下进行身份认证而带来的时间上和能量上的浪费,提高了认证效率,同时与传统的点到点的认证相比,能量消耗相对较少。     

Insights into the influence of fluorination positions on polymer donor materials on photovoltaic performance

To explore the influence of fluoro substitution position and number on optical, electrochemical and photovoltaic properties, three novel donor-acceptor (D-A) alternative copolymers (PHF, PFH and PFF) were synthesized by Stille polycondensation of 2,3-diphenyl-5,8-di(thiophen-2-yl)quinoxaline (DTQx) acceptor unit and indacenodithiophene (IDT) donor unit. As films, PHF and PFF comprising two fluoro substituents on the lateral phenyl groups displayed a broad absorption ranging from 350 to 700 nm; whereas PFH containing two fluorine atoms on the polymer main chain exhibited a slightly narrower absorption ranging from 350 to 650 nm. In addition, fluoro substitution on the polymer main chain can lower the HOMO level of the resulted polymers. As expected, PFH and PFF possess deeper HOMO energy level than PHF. Polymer solar cells (PSCs) were fabricated with these three polymers as donor materials and PC₇₁BM as acceptor material. PHF based PSCs gave a power conversion efficiency (PCE) of 7.2% with a V_oc of 0.84 V, a J_sc of 12.46 mA/cm² and an FF of 0.69. And PFH based PSCs showed a PCE of 6.19% with a V_oc of 0.93 V, a J_sc of 9.57 mA/cm² and an FF 0.70. However, a PCE of only 2.9% with a V_oc of 0.92 V, a J_sc of 4.61 mA/cm² and an FF of 0.68 was obtained for PFF based PSCs. Transmission electron microscopy (TEM) and resonant soft X-ray scattering (R-SoXS) studies indicated that the introduction of four fluorine atoms at each repeating unit can spoil the morphology of active layer. These results highlight the importance of fluorination position and number to the performance of PSCs.     

弹体撞击作用下平纹织物的动态响应分析

利用LS-DYNA有限元软件模拟弹体撞击作用下平纹织物的动态过程,分析织物断裂前的变形特性以及能量吸收特性,讨论边界约束条件和弹体形状对织物动态响应的影响。结果表明:纱线应变能和纱线动能是弹体动能转变的最主要形式,在给定计算的时间内,对于四边无约束、对边固定约束和四边固定约束3种边界条件,不论弹头形状采用平头、半球头和卵形头中的哪一种,两者之和占弹体动能损失量的比例不小于74.6%。模拟结果还表明,边界约束条件和弹体形状对织物的变形、应力分布以及能量吸收特性均有明显影响。边界条件不同,纱线动能和纱线应变能占弹体动能损失量的比例会发生较大变化,织物的能量吸收特性也不同。弹体头部形状不同,受撞击区影响的纱线数目也不同,弹头越钝,织物中抽拔出的纱线数目越多。从织物结构的抗弹性能角度看,织物结构抗钝头弹体的穿透能力要优于尖头弹体。     

浅析网络和计费数据核对方法

本文阐述了网络和计费比对的分析过程,通过对比工作及时发现、处理网络和计费突发问题,保障网络设备安全运行和计费话单数据的准确.     

Optimal fault margin in a computer system

This paper suggests a stochastic model how to determine a fault margin in a computer system, who fails when the total number of hidden faults exceeds a threshold level N of tolerance: A fault occurs at a non-homogeneous Poisson process, and (i) becomes system failure with probability p₁, (ii) becomes hidden fault with probability p₂ and is accumulated, or (iii) is removed with probability p₃. The expected cost rate to system failure is derived, and an optimal number N^* to minimize it is discussed. A numerical example is finally given.     

差分比例运算电路的设计方法

本文分析了一些文献给出的差分比例运算电路的运算关系,指出在输入端电阻平衡时输入信号比例系数的取值范围受到限制.在深入分析比例系数之差与平衡条件之间关系的基础上,给出了输入信号以任意比例系数参与运算的改进方案,使电路具有普遍适用性,并给出了电路的设计方法与步骤.