A Cooperative Schema between Web Sever and Search Engine for Improving Freshness of Web Repository

0 IntroductionTIon tceorpneet w ,itthhefr cerqauwelnetr sch oafn sgeeasr cohf tehneg iinnfeo rnemeadti toon uopnd tahteethe web pages visited. Different pages have different changefrequencies[1].Sothe crawlers must firstly esti mate which pa-ges need to b…     

Integrating Multi-Source Web Records into Relational Database

How to integrate heterogeneous semi-structured Web records into relational database is an important and challengeable research topic. An improved model of conditional random fields was presented to combine the learning of labeled samples and unlabeled database records in order to reduce the dependence on tediously hand-labeled training data. The pro- posed model was used to solve the problem of schema matching between data source schema and database schema. Experimental results using a large number of Web pages from diverse domains show the novel approach＇s effectiveness.     

A CORBA-Based Multidatabase System——Panorama Project

0　ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｎｅｅｄｆｏｒｉｎｔｅｇｒａｔｉｏｎｏｆｄｉｆｆｅｒｅｎｔｄａｔａｂａｓｅｍａｎａｇｅｍｅｎｔｓｙｓｔｅｍｓ (ＤＢＭＳｓ) ,ｍａｋｉｎｇｄｉｆｆｅｒｅｎｃｅｓｂｅｔｗｅｅｎｔｈｅｓｅｓｙｓｔｅｍｓｉｎｖｉｓｉｂｌｅａｎｄｐｒｏｖｉｄｉｎｇｕｓｅｒｓｗｉｔｈａｕｎｉｆｏｒｍａｃｃｅｓｓｔｏａｌｌｔｈｅｄａｔａｂａｓｅｓｈａｓｇｒｏｗｎｒａｐｉｄｌｙｄｕｒｉｎｇｔｈｅｌａｓｔｄｅｃａｄｅ .Ｈｏｗｅｖｅｒ,ｄａｔａｂａｓｅａｕｔｏｎｏｍｙａｎｄｈｅｔｅｒｏｇｅｎｅｉｔｙ…     

基于UML和XML Schema的作战计划建模

通过对作战计划基本构成的分析 ,提出作战计划的核心元素是“任务”和“行动”。利用面向对象的方法 ,建立了作战计划的数据模型 ,并用 UML静态关系图描述了该模型。在当前没有直接可参照标准的情况下 ,提出了从 UML静态关系图到 XML Schema的转换规则。以转换规则为基础 ,构造了作战计划的 XMLSchema,建立了作战计划的文件实例 ,为作战计划的可视化建立了基础。     

禁忌遗传算法在TSP中的应用

提出了带有禁忌交叉、变异的改进遗传算法,并将其应用于典型的TSP问题的求解.在求解过程中引入禁忌信息减小生成子代的模板空间的同时,加入张驰效应使得在禁忌操作中不丢失问题的最优解,从而改善了遗传算法的收敛速度.仿真数据表明,禁忌遗传算法比传统遗传算法在TSP问题中算法运行初期具备更好下降性,扩展了遗传算法在中、大规模NP-Hard问题快速求解中的应用.     

关系数据库系统移植中模式优化与冲突机制的设计

在深入研究异构数据库在模式和SQL语法等方面差异的基础上,设计了可扩展的冲突检查和处理机制,通过对潜在的冲突元素进行针对性调整避免模式冲突的不利影响.同时为了向上层应用程序屏蔽数据库移植中的模式调整,提出了在运行期间动态调整操作请求来保证数据库操作的准确性.     

XML Schema派生和重用机制

针对XML schema不能直接转换为关系模式，笔者设计了结构字典存贮结构信息和约束信息，利用贪心算法实现了机制映射为关系模式.实验结果表明：结构字典和算法对重构XML文档提供了有力支持.     

正交试验法优选雪莲花多糖提取工艺

研究雪莲花药材的水提取最佳工艺.方法:通过L9(3)4正交试验设计,以)莲多糖和总固物收率为考察指标,探讨)莲花水提取工艺中的几个影响因素.结果:试验结果方差分析表明提取次数和提取时间为主要影响因素,而溶剂用量影响不显著.结论:最佳提取工艺为加入药材10倍量水煎煮60min,反复提取3次.     

活动缓存模式在知识管理系统中的应用

动态文档正在成为Web内容中越来越重要的组成部分,获取动态内容的缓存成为影响Web规模的重要课题.笔者提倡用“活动缓存模式”来支持动态内容在Web代理上的缓存.这种模式允许服务器提供“缓存小应用”,这些小应用与内容绑定,需要代理根据缓存命令中判定的结果调用缓存小应用来完成必要的处理,而不需要与服务器联系.说明活动缓存模式涉及的协议、接口和安全机制,阐述了在当前的知识管理系统中如何引入活动缓存机制,以此来解决在应用规模不断扩大和数据量不断增加的情况下知识管理系统服务器服务性能问题.     

Study on extracting method of single slope surface shape based on DEM:taking Wanzhou district of three gorges reservoir area as example

This paper focused on the extracting method of single slope shape. Applying the software of ARCGIS 9.0, DEM (digital elevation model) was established. From the DEM, topographic characters, including valleys and ridges were extracted. Some valley lines were extended in order to intersect with the ridges nearby. All slope were divided into different slope surface, which enclosed by valleys and ridges. And the slope surface shapes were defined three types, Line Slope, Upper-concave and lower-convex slope, Upper-convex and lower-concave slope, according to their functions. And the judge formula of single slope surface shape was brought forward. Taking Wanzhou District as test area, it indicates that auto-extracting method of single slope surface shape has high precision relatively. This study can provide references to the studies of region geological disasters prevention and cure.