SET协议模型的改进与SMV分析

在以Lu&Smolka对SET协议支付过程的简化模型为研究对象的情况下,进行形式化建模和有限状态机模型。同时应用CTL对相应的安全性质进行形式描述,并在网络环境被入侵者控制的假设下,利用SMV分析了协议的认证性、保密性和完整性,发现攻击并对该攻击所产生的影响进行了讨论。最后修改其协议模型对改进后的协议进行分析和检验,说明了SET协议独具特色的双重签名在整个协议运行中至关重要。     

浅谈基于Flex技术的RIA设计

RIA(Rich Internet Applications,富互联网应用)技术结合了桌面应用和互联网应用的优点,它能够指导我们开发出更丰富、互动、友好的用户界面,而Flex(最新版名为Flash Builder)即是优秀的RIA开发技术之一。文中结合Flex的特点基于ActionScript脚本语言和MXML标签语言,对FlexRIA的软件框架、设计模式以及数据交互等进行探讨。     

一种基于模型检测的二进制程序脆弱性分析框架

针对二进制程序脆弱性分析的实际需求,提出了一种基于模型检测的二进制程序脆弱性分析框架。首先定义了二进制程序的抽象模型,描述了基于有限状态自动机的软件脆弱性形式化表示和基于事件系统的软件安全属性表示方法。在此基础上,提出了基于模型检测的脆弱性分析过程和算法。根据该分析框架,设计并实现了二进制程序脆弱性分析工具原型。通过脆弱性分析实验,详细说明了该框架的工作原理,验证了该分析方法的有效性。     

基于CMA—ES算法的支持向量机模型选择

研究模型选择对支持向量机(SVM)的泛化性能有着重要影响。针对传统梯度算法对初始值敏感及网格搜索法计算复杂的缺点,为了提高全面优化能力和分类精度,提出了一种基于协方差矩阵自适应进化策略(CMA-ES)的支持向量机(SVM)模型优化算法,通过对SVM泛化性能界(Bounds on Generalization Performance)的优化求解,实现了基于CMA-ES算法的SVM模型选择。在标准数据集上的实验结果表明:相比遗传算法和梯度算法,上述方法能够在较小计算代价下得到更优的超参数,提高支持向量机的预测精度稳定性,尤其适合大样本数据条件下的模型选择。     

BP神经网络PID控制器在工业控制系统中的研究与仿真

针对实际被控对象的时变性和非线性的特点,本文将基于BP神经网络PID的控制器应用于工业控制系统中,同时设计了三层BP神经网络并对BP神经网络PID控制器的算法进行了分析。仿真结果的分析表明：本文所设计的BP神经网络PID控制器在跟随性能、抗扰性能和鲁棒性能方面表现出了良好的控制效果。     

基于YNCIM模型的云南电网统一信息模型共享平台研究

为了满足生产控制系统与信息管理系统间通信的需求,对云南电网统一信息模型共享平台进行了研究。在对云南电力企业信息化建设现状进行分析的基础上,提出了基于YNCIM模型的统一电网信息模型,完成了统一电网信息模型的构建。对主网模型、配网模型和客户模型进行了详细阐述,使信息集成和数据共享过程得以有效实现,此外还对基于元对象机制技术的统一电网信息模型管理系统做了进一步介绍,为模型管理的完整一致及科学准确提供了制度和技术层面的支撑,为模型管理系统建设和完善提供参考。     

Speech separation using speaker-adapted eigenvoice speech models

We present a system for model-based source separation for use on single channel speech mixtures where the precise source characteristics are not known a priori. The sources are modeled using hidden Markov models (HMM) and separated using factorial HMM methods. Without prior speaker models for the sources in the mixture it is difficult to exactly resolve the individual sources because there is no way to determine which state corresponds to which source at any point in time. This is solved to a small extent by the temporal constraints provided by the Markov models, but permutations between sources remains a significant problem. We overcome this by adapting the models to match the sources in the mixture. We do this by representing the space of speaker variation with a parametric signal model-based on the eigenvoice technique for rapid speaker adaptation. We present an algorithm to infer the characteristics of the sources present in a mixture, allowing for significantly improved separation performance over that obtained using unadapted source models. The algorithm is evaluated on the task defined in the 2006 Speech Separation Challenge [Cooke, M.P., Lee, T.-W., 2008. The 2006 Speech Separation Challenge. Computer Speech and Language] and compared with separation using source-dependent models. Although performance is not as good as with speaker-dependent models, we show that the system based on model adaptation is able to generalize better to held out speakers.     

Does stock repurchase declaration affect stock price? Differences between the electrics industry and other industries

This study is to discuss the impact of stock repurchase declaration and purpose of repurchase on the stock price in the backdrop of listed companies on Taiwan’s stock market. Event Study Method is employed to discuss stock price fluctuations while GARCH (Generalized Autoregressive Conditional Heteroscedasticity) is applied to estimate the Market Model regressive coefficients. The samples consisted of companies declaring first stock repurchase are selected from August 9, 2000 to December 31, 2005 with a precondition that all the companies shall be listed ones 150 days prior to declaration. The study results reveal that companies from other industries have considerably bigger average CAR than companies of the electrics industry before and after the declaration of stock repurchase. Companies with application purpose of “maintain stockholders’ equities and corporate credit” have considerably bigger average CAR than companies with application purpose of “transferring stocks to employees”. In industries other than electrics, companies with application purpose of “maintain stockholders’ equities and corporate credit” have bigger accumulated abnormal return response than companies with application purpose of “transferring stocks to employees”. In case of “maintain stockholders’ equities and corporate credit” as the application purpose of stock repurchase, companies from industries other than electrics have relatively higher average CAR response. The empirical study results can serve as a reference for the listed company management and to related academic studies.     

基于混合高斯模型的目标差分自适应背景模型

提出一种自适应背景更新率的方法。在混合高斯背景模型基础上。通过混合高斯匹配将前后两帧分割出的运动目标作差分。差分后再次采用混合高斯匹配分辨出过去目标区和当前目标区。在背景更新的过程中,加大过去目标区的更新率,让运动目标在出现停滞状态时给背景模型带来的干扰区域得到快速恢复。试验结果表明,该方法有效地提高背景模型的鲁棒性。     

车载雷达防追尾预警系统中的目标跟踪研究

考虑毫米波雷达测量的误差和噪声的存在,为了提高毫米波雷达汽车防追尾预警系统的可靠性,设计了一个多模型算法实现对机动车辆的准确跟踪。针对汽车在高速公路上最常见的匀速、匀加速及转弯运动模型进行仿真实验,结果表明该算法能够有效地跟踪前方行驶车辆,探知自车与前车之间距离信息、速度信息等,从而降低雷达虚警率。