无线局域网中基于RC4的加密算法的分析与改进

分析RC4加密算法自身的缺陷和无线局域网WEP协议对RC4的误用,介绍了TKIP协议在安全性方面的改进。     

Half-time image reconstruction in thermoacoustic tomography

Thermoacoustic tomography (TAT) is an emerging imaging technique with great potential for a wide range of biomedical imaging applications. In this paper, we propose and investigate reconstruction approaches for TAT that are based on the half-time reflectivity tomography paradigm. We reveal that half-time reconstruction approaches permit for the explicit control of statistically complementary information that can result in the optimal reduction of image variances. We also show that half-time reconstruction approaches can mitigate image artifacts due to heterogeneous acoustic properties of an object. Reconstructed images and numerical results produced from simulated and experimental TAT measurement data are employed to demonstrate these effects.     

A Novel Approach for Redirecting Module in Honeypot Systems

1 Introduction Computer network security has been focus on passivedefense strategies usingtools and conceptslike Firewall ,Intrusion Detection System(IDS)[1 ~3]. This is an un-reasonable situation,because users have to protect com-puter systems perfectly, while hackers can use one ofvulnerabilities to attackthe systems . We are alwaysin apassive position.The bad guys have theinitiative .Theyhave unli mited resources and attack you whenever theywant , however they want . Moreover ,in a trad…     

基于结构化噪声矩阵补全的Web服务QoS预测

随着面向服务计算技术的快速发展,越来越多具有相同或相似功能的Web服务被部署在网络上。用户进行服务选择之前,通常需要根据历史调用信息对未使用过的服务QoS进行预测。由于历史调用信息收集过程缺乏有效的监督和约束机制,所采样的QoS信息往往容易受到结构化噪声污染,从而导致现有方法预测性能急剧下降。为了克服这个困难,通过将Web服务QoS预测问题建模为L2,1范数正则化矩阵补全问题,提出了一类基于结构化噪声矩阵补全的Web服务QoS预测方法。真实数据集上的实验结果表明,该方法不仅能精确地辨识出QoS采样矩阵中噪声行所在位置,而且能对缺失Web服务QoS进行有效预测。     

VHF-PECVD制备微晶硅材料及电池

采用VHF-PECVD技术制备了不同功率系列的微晶硅薄膜和电池,测试结果表明：制备的适用于微晶硅电池的有源层材料的暗电导和光敏性都在电池要求的参数范围内．低功率或高功率条件下,电池从n和p方向的喇曼测试结果是不同的,在晶化率方面材料和电池也有很大的差别,把相应的材料应用于电池上时,这一点很重要．采用VHFPECVD技术制备的微晶硅电池效率为5%,Voc=0.45V,Jsc=22mA/cm2,FF=50%,Area=0.253cm2．     

A universal ion implantation model for all species intosingle-crystal silicon

A physically based model for ion implantation of any species into single crystal silicon has been developed, tested and implemented in the ion implant simulator, UT-MARLOWE. In this model, an interpolation scheme, based on mathematical properties of ion-target interatomic potential, was employed and implemented to calculate the scattering process. Using this scheme, the resulting energy, direction and momentum of the ion and target can be derived from the existing scattering tables of UT-MARLOWE without calculating the entire scattering process. The method has advantages in terms of both accuracy and computational efficiency, as well as significantly reduced cost of code development. The impurity profiles and damage profiles predicted by the model simulations have been compared with secondary ion mass spectroscopy (SIMS) and Rutherford backscattering spectrometry (RBS), and excellent agreement with experimental data has been achieved     

甜菜根端细胞微核诱变的研究

本文以HgCl_2和明矾(AlK(SO_4)_2·12H_2O)两种化学试剂,诱变甜菜种子根尖细胞微核。结果表明,经诱变的细胞微核率明显高于对照组,而HgCl_2诱变的细胞微核率明显高于明矾组,在此,HgCl_2诱变微核的最佳度为浓1.0ppm,并对不同分裂时期的微核率进行了统计分析,试探讨了微核细胞类型及其发生和形成过程。     

聚氨酯——聚丙烯酸酯复合聚合物乳液的研究

本文研究了几种聚氨酯——聚丙烯酸酯乳液复合的方法，制备了新单体N-（4’-甲基3’-二正丁脲基）苯基氨基甲酸内烯酰氧-2-丙酯，使其与丙烯酸酯类单体共聚，显著提高了聚合物的抗张强度，简单介绍了聚合物膜接技法，共混复合法和种子聚合法的实施方法，聚合物膜性能及粒子结构等有关研究内容，实验表明，用几种方法都可以获得综合性能好的复合聚合物乳液。     

在柔性变焦系统中的压力变焦镜

从理论上和实验上对水冷镜的镜面曲率半径随压力变化的规律作了研究。对压力变形后镜面相对于球面作了波像差分析，分析表明压力变焦镜用于中红外激光系统是合适的     

注入种子CuBr激光器中的光谱控制

报道了采用注入种子方法．对ＣｕＢｒ激光器进行激光模式控制的实验结果。实现了单纵模ＣｕＢｒ激光脉冲的注入放大，获得了功率为１００ｍＷ水平的窄线宽铜激光辐射．在理论上分析了短脉冲高增益激光器中注入种子过程，讨论了在注入种子ＣｕＢｒ激光器中进行光谱控制的实验结果．