丝氨酸卟啉及其配合物的合成、光谱和催化性能

本文合成了一种新型的尾式丝氨酸卟啉５对（Ｎ－丝氨酸丁氧基）苯基－１０,１５,２０－三（对氯苯基）卟啉Ｈ２Ｐｓｅｒ和它的钴、钯配合物ＭＰｓｅｒ,选择ＭＰｓｅｒ－Ｚｎ－Ｏ２－ＨＡｃ－Ｉｍ（Ｍ＝Ｃｏ（Ⅱ）、Ｐｄ（Ⅱ）为模拟体系,研究了钴、钯配合物的催化氧化性能。实验结果表明,ＣｏＰｓｅｒ、ＰｄＰｓｅｒ对催化氧化环己烯无明显诱导期。ＰｄＰｓｅｒ具有很强的催化活性,转化率可达９１％,可望应用在催化氧化工业中。     

<Emphasis Type="Italic">H</Emphasis><Subscript>∞</Subscript> fault detection for linear singular systems with time-varying delay

This paper deals with the problem of H _∞ fault detection for a kind of linear singular systems with time-varying delay. A generalized form of observer-based fault detection filter (FDF) is first used as a residual generator. Then the design of H _∞-FDF is formulated in the framework of H _∞ filtering. By applying Lyapunov-Kravoskii function approach, delay-dependent conditions on the existence of the H _∞-FDF, which ensure asymptotic stability and a prescribed H _∞ performance level, are derived. With the aid of a cone complementarity linearization technique, an iterative algorithm is proposed to calculate the parameter matrices of the H _∞-FDF in terms of linear matrix inequalities. A numerical example is given to illustrate the effectiveness of the proposed algorithm.     

Ensemble of surrogates with recursive arithmetic average

Surrogate models are often used to replace expensive simulations of engineering problems. The common approach is to construct a series of metamodels based on a training set, and then, from these surrogates, pick out the best one with the highest accuracy as an approximation of the computationally intensive simulation. However, because the choice of approximate model depends on design of experiments (DOEs), the traditional strategy thus increases the risk of adopting an inappropriate model. Furthermore, in the design of complex product system, because of its feature of one-of-a-kind production, acquiring more samples is very expensive and intensively time-consuming, and sometimes even impossible. Therefore, in order to save sampling cost, it is a reasonable strategy to take full advantage of all the stand-alone surrogates and then combine them into an ensemble model. Ensemble technique is an effective way to make up for the shortfalls of traditional strategy. Motivated by the previous research on ensemble of surrogates, a new technique for constructing of a more accurate ensemble of surrogates is proposed in this paper. The weights are obtained using a recursive process, in which the values of these weights are updated in each iteration until the last ensemble achieves a desirable prediction accuracy. This technique has been evaluated using five benchmark problems and one reality problem. The results show that the proposed ensemble of surrogates with recursive arithmetic average provides more ideal prediction accuracy than the stand-alone surrogates and for most problems even exceeds the previously presented ensemble techniques. Finally, we should point out that the advantages of combination over selection are still difficult to illuminate. We are still using an “insurance policy” mode rather than offering significant improvements.     

Xen安全机制探析

虚拟化技术正在成为一种主流的网络应用,Xen作为一种虚拟化产品,已经在开源社区中得到广泛推广,其安全风险也受到业界关注。文章系统分析了Xen的安全框架XSM的实现机制和关键技术,介绍了ACM和Flask两种不同的安全构架,深入剖析了其中安全模型的具体实现原理和方法,并结合实际应用中的场景进行了安全保护分析。     

远程勘验取证分析软件开发与实现

远程勘验分析技术是计算机取证技术的一个重要分支,而如何实现自动、智能远程勘验分析目标网站是一项重要研究课题。文章简要介绍了远程勘验取证分析软件＂网际无痕特种兵＂基本原理和功能,进行了实证性分析并取得了积极的成果。     

嵌入式地址智能分配系统的设计与实现

针对传统的地址固化方式存在设备维修互换困难的问题,提出了一种嵌入式地址智能分配系统的设计方案。该系统从第一个通信模块即第一台设备开始,由近及远依次自动编号,地址号存入到每个通信模块的数据存储器中,并可随时通过串口输出。该系统中所有的通信模块的硬、软件完全相同,使设备的维修互换不受任何影响、摆放位置不受限制。实际应用表明,该系统设计合理,能够准确地分配地址。     

高性能机群计算本科教学研究

针对目前高性能机群人才需求旺盛而高校对高性能机群计算知识普及不够的现状,以培养工程实践性机群系统管理人员为目标,阐述面向高校计算机专业本科生开设高性能机群计算课程的教学目标;并进行课程设计,包括教学内容及教材选取、课时安排以及教学方法设计。北京工业大学的教学实践表明,上述课程设计取得了较好的教学成效。     

新型单周控制三相四线制并联混合型有源电力滤波器研究

提出了1种基于单周控制单极调制方式的新型三相四线制并联混合型有源电力滤波器(activepowerfilter,APF)结构,以解决四桥臂和三桥臂结构分别存在的开关损耗大、控制结构复杂等问题,同时该方案不需要单独对中线电流进行补偿,且能有效地解决直流分量问题。对新型结构进行了建模,推导了单周控制方程,最后进行了MATLAB仿真验证,结果证实了该方案的可行性。     

虚拟软件企业合作伙伴选择多智能体仿真研究

虚拟软件企业能否成功很大程度上取决于其组建过程,而组建过程中关键的环节是选择合适的合作伙伴。因此将虚拟软件企业合作伙伴选择问题作为研究对象,分析了其微观作用机制,采用多智能体建模与仿真方法,建立了合作伙伴选择多智能体模型,设计了相应的仿真实验,研究了不同决策目标下的合作伙伴选择机制。研究表明,成本最低法、工期最短法和质量最优法这3种单目标决策方法能够达到各种决策目标的最优化,但是稳定性较差;综合最佳法这种多目标决策方法能够实现软件项目总工期和总质量之间的平衡,并且稳定性较好。     

空间几何对象相对位置的新安全判定方法

针对空间几何对象相对位置判定问题提出一种新的解决方案,也就是运用矩阵秩的概念和一般矩阵求和的安全两方计算协议秘密判定空间几何对象相对位置问题.关于此问题,之前罗永龙教授设计了对应成比例判定协议,而文中则利用矩阵秩的概念和一般矩阵求和的安全两方计算协议设计了一些基础的空间几何对象相对位置安全判定协议.运用此协议解决了空间中的平面与平面位置关系问题、平面与直线位置关系问题和直线与直线位置关系问题.提出的新安全判定方法不久解决了空间几何对象相对位置判定问题,也将在其他安全多方计算问题中起到重要作用.