网络攻击与防范研究

随着信息时代的到来,越来越多的企业或个人逐步意识到信息安全防护的重要性。计算机网络、数据通信、电子商务、办公自动化等领域需要解决信息安全问题。如何保护企业或个人的信息系统免遭非法入侵？对目前计算机网络存在的网络攻击方法进行了分析,从发现正确的目标到执行攻击,并提出相应的防范措施。     

Understanding dengue fever dynamics: a study of seasonality in vector-borne disease models

Dengue fever dynamics show seasonality, with the disease transmission being higher during the warmer seasons. In this paper, we analyse seasonally forced epidemic models with and without vector dynamics. We assume small seasonal effects and obtain approximations for the real response of each state variable and also for the corresponding amplitude and phase via decomposition of the sinusoidal forcing into imaginary exponential functions. The analysis begins with the simplest susceptible-infected-susceptible (SIS) model, followed by the simplest model with vector dynamics, susceptible-infected-susceptible for hosts and uninfected-vector (SISUV). Finally, we compare the more complex susceptible-infected-recovered (SIR) and susceptible-infected-recovered for hosts and uninfected-vector (SIRUV) models and conclude that the models give basically the same information when we replace, in the SIR model, the human infectivity by a function of both human and mosquito infectivities.     

A mass spectrometric strategy for profiling glycoproteinoses, Pompe disease, and sialic acid storage diseases

Glycoproteinoses, Pompe disease, and sialic acid storage diseases are characterized by a massive accumulation of unprocessed oligosaccharides and/or glycoconjugates in urine. The identification of these glycocompounds is essential for a proper diagnosis. In this study, we investigated the potential of MALDI‐TOF‐MS to identify glycocompounds present in urine from patients with different inborn errors of glycan metabolism. Urinary glycocompounds were permethylated, and analyzed using GC‐MS and MALDI‐TOF‐MS. In order to confirm tentative assignments, a second aliquot of urine was purified on a C18 Sep‐Pak cartridge and glycocompounds were desalted on a column of nonporous graphitized carbon. The glycocompounds were then sequentially on‐plate digested using an array of exoglycosidases. A range of disease‐specific oligosaccharides as well as glycopeptides was identified for all oligosacchariduria models. In addition, free sialic acid accumulated in urine from a patient suffering from French‐type sialuria, has been detected by a GC‐MS approach, which could be applied to other sialic acid storage diseases. This procedure is simple, and can be performed in few simple steps in less than 24 h. This current method can be applied for newborn screening for other inherited metabolic diseases as well as for assessing treatments in clinical trials.     

微博转发预测算法评测系统的建立及性能比较

为解决微博转发行为预测问题,提出了一个基本的预测算法评测系统框架.该系统解决了原始微博数据的抓取和预处理,以及用户微博的转发和忽略行为的判定,微博和用户的特征提取等问题,为解决微博转发行为预测问题提供了技术基础.详细分析了现有文献和工作中的微博转发行为预测算法,阐述了它们的基本原理.通过定量实验分析了不同微博转发行为预测算法的在局部预测问题和全局预测问题方面的性能,并且从算法的原理等方面出发给出了定性的分析.     

基于图像处理的作物病害自动识别系统的研究

为了实现对作物病害检测与防治的自动化,构建了一个基于叶片病斑图像处理的计算机诊断系统,以实现作物叶部病害的自动识别。该系统依据作物病叶颜色差异,用EM算法和偏微分方程水平集模型等图像分割算法,从图像中获取完整准确的病斑;然后提取病斑的颜色、形状和纹理特征,运用主成分分析方法对数据进行降维处理;最后采用神经网络和支持向量机方法对这些特征进行学习与分类,以及病害识别。系统已试用于黄瓜、番茄等园艺作物叶部病害的自动诊断与识别,其优点是自动化程度高,识别准确率在一定条件下较好。     

山东省棉花主要病害的发生现状与防治

山东省棉花病害种类共有１９种，根据其发病部位和时期等特点习惯了分为四大类：苗期病害的发生枯黄萎病，铃部病害和叶部病害，其中危害性最大的是棉花枯萎病和黄萎病。某些年份，立枯病，黑斑病和铃疫病也能引起较大的损失。     

知识管理框架ReKM在农业病虫害诊断中的应用

在农业病虫害诊断领域，传统的专家系统往往在设计时就硬编码好了知识结构，在不重新改动代码的情况下，具有很差的扩展性。介绍了一个基于本体和案例推理的可重构知识管理框架ReKM。该框架利用本体作为知识结构的描述，由知识存储层、本体层和应用层组成。利用本体模型的可重构特性，一定程度上克服了传统专家系统可扩展性不足的缺点。文中详细阐述了框架中基于案例的检索算法和简单推理的概念。最后介绍了基于该框架开发的一个系统在某农科院病虫害诊断领域的应用情况和今后研究的方向。     

热镀锌企业清洁生产实例研究

清洁生产是一种新的污染防治战略。本文在对TF公司生产状况的研究过程中,发现该公司生产中因除锈剂浓度比例过高、助镀剂选用不当而存在的污染问题。通过清洁生产的整改方式,使该公司既消除了污染问题,又产生了可观的经济效益。从而说明,清洁生产以较少的投入,实现了经济效益、环境效益和社会效益的统一。     

反弧型挑浪嘴式防洪墙对削减波浪爬高的试验研究

通过对防洪墙顶部做成反弧型挑浪嘴式对削减波浪爬高的试验研究 ,探讨一种对海滨、水库、湖泊及沿江电厂既安全可靠又经济合理的防浪墙形式 ,以达到降低堤顶高度 ,减少造价、改善景观的目的     

压力容器清洁厂房的建造

论述了建造用于制造不锈钢、铝、铜、镍、钛及其合金压力容器清洁厂房的重要性和必要性 ,提出了压力容器清洁厂房的建造要求及管理规定 ,给出了清洁厂房的部分考核依据。