流分类技术的研究

介绍了流分类算法的概念以及对流分类算法的要求;把目前存在的流分类算法分成三类:多维查找转换为一维查找算法、相关区域查找算法、独立区域查找算法,并对各类算法的性能进行了讨论;通过引入并行流分类算法说明了流分类算法的研究重点是减小存储空间和提高更新速度。     

基于NetFlow V9协议的网络信息采集研究与实现

NetFlow是目前主要的网络信息采集协议之一,V9是它的最新版本,它可在最大限度减小对路由器/交换机性能影响的前提下,提供详细的数据流统计信息。该文结合网络性能管理软件项目(NPMS)的开发,讨论了基于NetFlow(V9)协议的网络信息采集的研究与实现,即对NetFlow(V9)数据流的解析与保存。     

Small domain estimation by empirical bayes and kalman filtering procedures - a case study

An application of empirical Bayes and Kalman filtering tecniques is reported, using live data from Indian Statistical Institute (ISI), Calcutta . to illustrate how initial small domain estimators may be vastly improved upon. A stratified two stage sampling procedure is adopted, allowing selection of first stage units with unequal probabilities but of second stage units with equal probabilities. Standard design-based estimators for domain totals are initialized based on domain specific survey data alone. Strength is then borrowed across domains and from past surveys. The resulting gains in efficacy are numlerically demonstrated, through replicated sampling from official records.     

Identification,Estimation, and Control of Uncertain Dynamic Systems: A Nonparametric Approach

This article is devoted to a presentation of the author' practice of the non-parametric estimation theory for the estimation, filtering, and control of uncertain dynamic systems. The fundamental advantage of this approach is a weak dependency on prior modeling assumptions about uncertain dynamic components. This approach appears to be of great interest for the control of general discrete-time processes, and in particular, biotechnological processes, which are emblematic of nonlinear uncertain and partially observed systems.     

钢轨铝热焊技术和钢轨弹力紧固装置在马钢行车大车钢轨上的联合应用

采用钢轨弹力紧固装置和钢轨铝热焊技术,减少钢轨接头,克服钢轨热胀冷缩带来的弊端,使得行车在钢轨上运行平稳可靠.     

基于状态空间模型的宏观经济因素对股市流动性的建模分析

证券市场的流动性是评估一国证券市场是否健康运转的重要指标。关于流动性的各种学术研究也是金融市场微观结构理论中的热点问题。本文主要考察宏观经济因素对时变的股市流动性的影响，选取度量股票流动性的指标以及宏观经济变量，针对行业分类的面板数据提出三个动态因子模型，并引入跨行业的能够捕捉风险聚集现象的潜在因子进行建模，利用状态空间模型与Kalman滤波进行分析和样本外流动性风险预测。我们提出的新颖的带回归效应的高斯面板数据时间序列模型，结合了用主成分的方法从大量宏观经济协变量中提取出来的因子，用来分析和预测股市的流动性风险，具有较强的信息挖掘作用。在对上证A 股的实证研究中，我们发现动态的潜在因子的引入对于防止流动性估计的偏差是需要的。     

Estimating the Population Survival Function Using Additional Information Recorded Over Time: a Filter Based Approach

Survival studies often collect information about covariates. If these covariates are believed to contain information about the life-times, they may be considered when estimating the underlying life-time distribution. We propose a non-parametric estimator which uses the recorded information about the covariates. Various forms of incomplete data, e.g. right-censored data, are allowed. The estimator is the conditional mean of the true empirical survival function given the observed history, and it is derived using a general filtering formula. Feng & Kurtz (1994) showed that the estimator is the Kaplan–Meier estimator in the case of right-censoring when using the observed life-times and censoring-times as the observed history. We take the same approach as Feng & Kurtz (1994) but in addition we incorporate the recorded information about the covariates in the observed history. Two models are considered and in both cases the Kaplan–Meier estimator is a special case of the estimator. In a simulation study the estimator is compared with the Kaplan–Meier estimator in small samples.     

The Ornstein-Uhlenbeck Dirichlet process and other time-varying processes for Bayesian nonparametric inference

This paper introduces a new class of time-varying, measure-valued stochastic processes for Bayesian nonparametric inference. The class of priors is constructed by normalising a stochastic process derived from non-Gaussian Ornstein-Uhlenbeck processes and generalises the class of normalised random measures with independent increments from static problems. Some properties of the normalised measure are investigated. A particle filter and MCMC schemes are described for inference. The methods are applied to an example in the modelling of financial data.     

公共计算机实验室软件系统管理与实践

通过对河北科技师范学院公共计算机实验室课程设置、机房安排、软件划分等内容的合理规划,软件的安装、测试、优化和完善等方面技术手段的应用,硬盘保护卡功能的有效运用以及网络技术的综合使用及多种手段的优化比较,构建了完整的高校公共计算机实验室软件系统管理模式,实现了对高校公共机房实验室设备的充分利用和高效维护,以及对公共机房软件系统的科学管理。     

LSA和MD5算法在垃圾邮件过滤系统的应用研究

随着对垃圾邮件问题的普遍关注,针对目前邮件过滤方法中存在着的语义缺失现象和处理群发型垃圾邮件低效问题,提出一种基于潜在语义分析(LSA)和信息-摘要算法5(MD5)的垃圾邮件过滤模型。利用潜在语义分析标注垃圾邮件中潜在特征词,从而在过滤技术中引入语义分析;利用MD5在LSA分析基础上,对群发型垃圾邮件生成"邮件指纹",解决过滤技术在处理群发型垃圾邮件中低效的问题。结合该模型设计了一个垃圾邮件过滤系统。采用自选数据集对文中设计的系统进行测试评估,经与Nave Bayes算法过滤器进行比较,证明该方法在垃圾邮件过滤上优于Nave Bayes方法,实验结果达到了预期的效果,验证了该方法的可行性、优越性。