计算机网络与防范研究

网络安全与防范分析是近年来国内外研究的热点问题之一。攻击者的技术和手段越来越多样化和高明化。计算机网络攻击与防范的研充就变得越来越重要了。论述了计算机网络面临的各种安全威胁方法及安全防范技术手段,对这些攻击给出相应的防范措施,并对入侵检测系统存在的不足给出了解决方案。     

基础位移激励下椭圆抛物面碳纤维索网的振动

在考虑温度变化的基础上,研究椭圆平面双曲抛物面碳纤维索网在基础激励下的非线性振动问题,建立了椭圆平面双曲抛物面碳纤维索网在基础位移激励下的非线性振动方程,采用Galerkin原理及KBM法求得了椭圆平面双曲抛物面碳纤维索网非线性振动的近似解．在把碳纤维索网与钢丝索网比较的基础上,讨论分析了位移激励、温度、振幅、外阻尼等因素对椭圆平面双曲抛物面碳纤维索网非线性振动的影响,得到了碳纤维索网对温度变化不敏感,而钢丝索网受温度的影响却很大,且碳纤维索网振动特性优于钢丝索网振动特性的结论．     

基于多信息融合技术的智能汽车防盗报警系统研究与设计

为完善汽车的防盗系统,提出研制的智能汽车防盗报警器是在ARM嵌入式系统的基础上,利用Dempster--Sharer证据理论融合密码识别、加速度传感、GPS全球定位信息,判断车辆的安全状况,再将车况信息通过GPRS无线通信网络发送到车主手机。实验室测试表明,系统实现了监控基本功能并满足实时性,增强了汽车安全性和智能报警性。     

On the equal-weight symmetric Boolean functions

Two important classes of symmetric Boolean functions are the equal-weight Boolean functions and the elementary (or homogeneous) symmetric Boolean functions. In this paper we studied the equal-weight symmetric Boolean functions. First the Walsh spectra of the equal-weight symmetric Boolean functions are given. Second the sufficient and necessary condition on correlation-immunity of the equal-weight symmetric Boolean function is derived and other cryptology properties such as the nonlinearity, balance and propagation criterion are taken into account. In particular, the nonlinearity of the equal-weight symmetric Boolean functions with n (n ≥ 10) variables is determined by their Hamming weight. Considering these properties will be helpful in further investigations of symmetric Boolean functions.     

Detection of urinary biomarkers for early diagnosis of acute renal allograft rejection by proteomic analysis

Acute allograft rejection has been recognized as a major impediment to improved success in renal transplantation. Timely detection and control of rejection are very important for the improvement in long-term renal allograft survival. Thus, biomarkers for early diagnosis of acute rejection are required urgently to clinical medication. This study seeks to search for such biomarker candidates by comparing patients' pre-treatment urinary protein profiling with their post-treatment urinary protein profiling. A total of 15 significantly and consistently down-regulated protein candidates were identified. Among them, alpha-1-antichymotrypsin precursor (AACT), tumor rejection antigen gp96 (GP96) and Zn-Alpha-2-Glycoprotein (ZAG) were selected for further analysis. The results indicated that Western Blot assay of AACT, GP96 and ZAG had advanced the diagnosis time of acute renal rejection by 3 days, compared with current standard clinical observation and laboratory examination. Furthermore, the double-blind detection revealed that the accuracy, sensitivity and specificity of the diagnosis of acute renal rejection of AACT, GP96 and ZAG were 66.67%/100%/60%, 83.33%/100%/80% and 66.67%/100%/60%, respectively, and 100%/100%/100% in combination. In conclusion, urinary protein AACT, GP96 and ZAG could be a set of potential biomarkers for early non-invasive diagnosis of the acute rejection after renal transplantation.     

Isoform-specific expression and characterization of 14-3-3 proteins in human glioma tissues discovered by stable isotope labeling with amino acids in cell culture-based proteomic analysis

Human 14-3-3 proteins have isoform-specific expression and functions in different kinds of normal or tumor cells and tissues. However, the expression profiling of 14-3-3 proteins and isoform-specific biological functions are unclear in human glioma so far. In our study, the expression levels and characterization of 14-3-3 isoforms in human glioma tissues were investigated by a sensitive, accurate stable isotope labeling with amino acids in cell culture-based quantitative proteomic strategy. As a result, except unexpressed 14-3-3σ, the other six isoforms, with different expression levels, were existed in glioma tissues and para-cancerous brain tissues (PBTs). 14-3-3β and η were upregulated, whereas 14-3-3ζ was downregulated in glioma tissues compared with that in PBTs. And the other three isoforms 14-3-3ε, θ, and γ had similar expression levels in human glioma tissues and PBTs. Western blot and immunohistochemistry analysis were both consistent with the quantitative proteomic data. The loss of expression of 14-3-3σ was further discovered due to DNA high methylation in its coding region in glioma by methylation-specific PCR analysis. These results indicated that the four isoforms, including 14-3-3β, η, ζ, and σ, may play important roles in tumorigenesis of human glioma, which is probably used as potential biomarkers for diagnosis and targets for treatment of human gliomas in future.     

Consensus protocols for discrete-time multi-agent systems with time-varying delays

This paper addresses consensus problems for discrete-time multi-agent systems with time-varying delays and switching interaction topologies and provides a class of effective consensus protocols that are built on repeatedly using the same state information at two time-steps. We show that those protocols can solve consensus problems under milder conditions than the popular consensus algorithm proposed by Jadbabaie et al., specifically, the presented protocols allow for the case that agents can only use delayed information of themselves, whereas the popular one is invalid. It is proved that if the union of the interaction topologies across the time interval with some given length always has a spanning tree, then in the presence of bounded time-varying delays, those protocols solve consensus problems.     

基于曲率流的点模型编辑方法*

为了对点模型表面进行保细节的自由形状编辑,提出了一种基于曲率流的点模型形状编辑方法。该方法定义了基于平均曲率流的光顺算子,通过此光顺算子获得点模型不同光滑程度的曲面表示。运用对应曲面上点之间的向量差进行相应几何细节的抽取,在相邻的曲面表示之间将几何细节剥离出来。用户可以在不同的曲面上进行自由形状编辑,而无须关心几何细节。在变形后的曲面上再将相应的几何细节映射回去,实现对模型保细节的变形。实验结果表明该方法是一种有效的点模型造型算法,在变形的同时,有效地保持了模型表面的细节特征。     

改进的多智能体遗传算法求解TSP研究

多智能体遗传算法是基于智能体对环境感知与反作用的能力提出的一种新的函数优化方法,具有很快的收敛速度,尤其是在优化超高维函数时更显示出了它的优越性。针对这一特点对该算法进行了适当的改进,在邻域正交交叉算子中采用精英保留策略,在自学习算子中引入邻域正交交叉算子并采用小变异概率以加快收敛速度。求解TSP的实验结果显示,改进后算法的性能有了较大的提高。