一种基于CloudStack的企业级云资源平台网络优化研究

在对云资源平台的现状进行分析后,提出了一种基于Cloud Stack的企业级云资源平台网络优化方案,通过与现有3种解决方案进行对比,展示了该方案的可靠性和有效性。同时,针对可能存在的风险和不足进行了充分的考虑和论证,并给出了应对措施。     

Analysis of the Insect OS-D-Like Gene Family

Insect OS-D-like proteins, also known as chemosensory (CSP) or sensory appendage proteins (SAP), are broadly expressed in various insect tissues, where they are thought to bind short to medium chain length fatty acids and their derivatives. Although their specific function remains uncertain, OS-D-like members have been isolated from sensory organs (including the sensillum lymph in some cases), and a role in olfaction similar to that of the insect odorant binding proteins (OBP) has been suggested for some. We have identified 15 new OS-D-like sequences: four from cDNA clones described herein and 11 from sequence databases. The os-d-like genes from the Anopheles gambiae, Apis mellifera, Drosophila melanogaster, and Drosophila pseudoobscura genomes typically have single, small introns with a conserved splice site. Together with all family members entered on GenBank, a total of 70 OS-D-like proteins, representing the insect orders Diptera, Dictyoptera, Hymenoptera, Lepidoptera, Orthoptera, and Phasmatodea, were analyzed. A neighbor joining distance phenogram identified several protein similarity classes that were characterized by highly conserved sequence motifs, including (A) N-terminal YTTKYDN(V/I)(N/D)(L/V)DEIL, (B) central DGKELKXX(I/L)PDAL, and (C) C-terminal KYDP. In contrast, three similarity classes were characterized by their diversion from these conserved motifs. The functional importance of conserved amino acid residues is discussed in relation to the crystal and NMR structures of MbraCSPA6.     

Kinetics of the thermal degradation and thermal stability of conductive silicone rubber filled with conductive carbon black

The kinetics of the thermal degradation and thermal stability of conductive silicone rubber filled with conductive carbon black was investigated by thermogravimetric analysis in a flowing nitrogen atmosphere at a heating rate of 5°C/min. The rate parameters were evaluated by the method of Freeman–Carroll. The results show that the thermal degradation of conductive silicone rubber begins at about 350°C and ends at about 600°C. The thermal degradation is multistage, in which zero‐order reactions are principal. The kinetics of the thermal degradation of conductive silicone rubber has relevance to its loading of conductive carbon black. The activation energies are temperature‐sensitive and their sensitivity to temperature becomes weak as temperature increases. In addition, the conductive silicone rubber filled with conductive carbon black has better thermal stability than that of silicone rubber without any fillers. Also, conductive silicone rubber filled with conductive carbon black has better thermal stability than that of silicone rubber filled with the same amount of silica. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1548–1554, 2003     

荧光法测定N-（α-烷苯氧基）十四酰基牛磺酸钠的临界胶束浓度

研究了一类以苯氧基作疏水支链的新型阴离子表面活性剂——N-（α-烷苯氧基）十四酰基牛磺酸钠（SAPTT）水溶液的紫外吸收光谱、探针（芘）稳态荧光发射光谱及自身稳态荧光发射光谱性质．研究结果表明，荧光探针（芘）法和自身稳态荧光法可用来测定这类表面活性剂的临界胶束浓度（CMC），且测定结果与表面张力法（吊片法）接近；与荧光探针（芘）法相比，对于所研究体系，自身稳态荧光法的灵敏度和准确性均较高，所测得CMC结果与表面张力法（吊片法）能较好地吻合．     

钛系催化剂陈化方式和条件对合成高乙烯基聚丁二烯橡胶的影响

本工艺以Ti(OC4H9)4-Al(i-C4H9)3为催化剂合成乙烯基聚丁二烯，采用催化剂陈化方式，考察了陈化温度和时间等条件对聚合的影响。结果表明，本体系高温陈化后可提高催化活性，降低Al用量；Ti－Bd－Al三元陈化的催化活性高于Ti－Al二元陈化；最佳陈化条件为n（Ti）：n（Bd）：n（Al）＝1：20：20，70℃陈化1h；与未陈化和低温陈化聚合的产物相比，高温陈化产品的分子量和1，2－结构含量较高，凝胶含量较低。     

基于遗传算法的多参数QoS网络路由算法

目前许多应用都有不同的高质量QoS保障需求,但QoS路由问题是一个非常复杂的问题,而且在两条独立的路径之间寻找可行路径是NP难题。同时,高速网络的QoS路由算法必须具有适应性、灵活性和智能性。论文提出了一种基于遗传算法的QoS路由算法,算法中选择两个QoS路由参数进行路由的优化,仿真结果表明该方法比传统的路由算法及单QoS参数的路由算法具有更高的性能。     

Hash签名在电子商务中的应用

Hash签名是一项应用于电子商务领域的安全技术,可实现电子商务的保密性、完整性、可鉴别性、不可伪造性和不可抵赖性.文章阐述了电子商务交易中Hash签名方案并对其进行分析,指出Hash签名的作用以及在电子商务中能够解决的实际问题.     

蚁群聚类能量分簇在802．11无线网络定位中的应用

IEEE 802．11无线网络以快速灵活的组网方式得到广泛部署和应用,其定位方法也成为近年研究热点。论文提出了一种基于蚁群聚类能量分簇RSSI指纹定位算法,利用蚁群信息素反馈机制优化能量聚类分簇和收敛速度,再根据能量指纹匹配定位节点位置。仿真实验表明,该算法定位精确,能很好地减小由信号波动引起的定位误差。     

一种卡尔曼增益约束滤波算法

在滤波过程中,将卡尔曼增益结合约束条件,可以有效地提高滤波精度.论文推导了含有卡尔曼增益约束条件的代价函数,根据Karush-Kuhn-Tucker（KKT）最小化的一阶必要条件,使用高斯牛顿法求出约束卡尔曼增益的最优约束解.最后对具有约束条件的目标跟踪问题进行了仿真实验,结果表明该算法的跟踪精度要高于普通卡尔曼滤波算法.     

带路径约束的双端网络可靠性分析磁

针对带路径约束的双端网络可靠性分析问题,即一个数据包从 S 点发送到 T 点,必须经过中间若干个节点,并且经过这些节点的先后顺序具有一定约束,提出了基于 BDD 的可靠性分析算法。该算法基于边扩展图实现路径约束,即在边扩展过程中只保留符合条件的约束路径,然后构建 BDD 以及进行双端网络可靠性分析。实例分析结果验证了算法的可行性和有效性。