Representing topological relationships for spatiotemporal objects

Several representations have been created to store topological information in normal spatial databases. Some work has also been done to represent topology for 3D objects, and such representations could be used to store topology for spatiotemporal objects. However, using 3D models has some disadvantages with regards to retrieving snapshots of the database. This paper aims at creating a spatiotemporal version of the sliced representation that supports efficient retrieval of snapshots of the past and that supports enforcing topological relationships. This paper aims to extend an earlier representation of moving objects so that it can also store and enforce some of the topological relationships between the objects. One use of such a representation is storing a changing spatial partition. As part of the effort to construct the model, an analysis of the topological relationships has been carried out to see which need to be stored explicitly and which can be computed from geometry. Both a basic time slice model and a 3D model are examined to determine how suitable they are for storing topological relationships. An extension of the time slice model is then proposed that solves some of the problems of the basic time slice model. Some algorithms for constructing the new model from snapshots of the objects along with an adjacency graph have been created. The paper also contains a short analysis on how to handle current time, as the time slice model is best at handling historical data, and on ways to speed up searches in a database in which objects of many types are connected to one another and many files therefore potentially need to be accessed.     

基于SSFNet的远程链接的实现

SSFNet是一种Internet网络协议仿真和建模软件,以基于Java和C 的SSF的软件框架所组成。本文使用DML实现了两个局域网的远程链接,仿真结果显示远程客户端运行应用程序在性能上将明显下降。     

体数据中物体之间结构关系的描述方法

体数据中不同的物体之间存在不同的结构关系,如隐藏关系、拓扑关系等,不同结构关系是影响用户理解体数据的重要特征之一。从分析体数据中物体之间关系入手,提出一个有效的体绘制应当定义一个从数据到绘制的映射,以便将数据中物体之间的每种关系映射到绘制空间。然后提出描述体数据中物体之间典型结构关系的体绘制方法。在绘制空间对物体之间的不同关系的描述增强了用户对体数据的理解,并拓展了体绘制在体数据分析中的功能。     

Oracle8i新特性与系统性能的保证

讨论Oracle8i引进的一些新特性在对大型数据库执行复杂的查询时如何保证整个系统的性能。     

电子病历的原生XML存储方式

详细分析传统的XML电子病历（Electronic Medical Record,EMR）存储方式．针对传统RMR存储方式修改表结构代价大,系统维护困难、负担加重,不能为XML文档建立索引并加快查询速度,不能充分利用XML数据资源、分解文档通常还会造成细节损失等缺点,提出一种新的电子病历原生XML存储方式。该方式不仅可以降低系统复杂度,而且结合行业新兴的XML数据操作语言可以方便地将稿历中的信息应用于医学信息统计、临床辅助诊断等其他领域,从而拓展电子病历的应用空间．     

SQL查询功能教学总结

本文以ACCESS软件为基础,根据给学生讲解SQL查询功能时,学生能较好地理解讲授的方式来总结SQL查询功能。     

Combining objects with rules to represent aggregation knowledge in data warehouse and OLAP systems

Data warehouses are based on multidimensional modeling. Using On-Line Analytical Processing (OLAP) tools, decision makers navigate through and analyze multidimensional data. Typically, users need to analyze data at different aggregation levels (using roll-up and drill-down functions). Therefore, aggregation knowledge should be adequately represented in conceptual multidimensional models, and mapped in subsequent logical and physical models. However, current conceptual multidimensional models poorly represent aggregation knowledge, which (1) has a complex structure and dynamics and (2) is highly contextual. In order to account for the characteristics of this knowledge, we propose to represent it with objects (UML class diagrams) and rules in the Production Rule Representation language (PRR). Static aggregation knowledge is represented in the class diagrams, while rules represent the dynamics (i.e. how aggregation may be performed depending on context). We present the class diagrams, and a typology and examples of associated rules. We argue that this representation of aggregation knowledge enables an early modeling of user requirements in a data warehouse project. A prototype has been developed based on the Java Expert System Shell (Jess).     

A shorthand preprocessor for IDMS COBOL

Aspects of software development using Codasyl COBOL DML are considered. In limited trials, a preprocessor which makes a terse DML syntax available has been found to increase programmer productivity and improve software quality.     

基于切片技术的GUI回归测试用例选择

本文通过分析基于GUI的面向对象软件系统中界面元素和类方法之间的依赖关系,应用程序切片技术,给出系统回归测试的方案.在系统修改后,通过系统中对象之间的依赖性界定修改波及的影响,再根据切片技术计算出相应的程序切片,进一步设计或选择有效的测试用例进行测试.     

基于外部记忆单元和语义角色知识的文本复述判别模型

文本复述判别是一个重要的句子级语义理解应用。该文提出了一个轻量级的基于记忆单元的单层循环神经网络模型,并结合语义角色标注知识帮助进行英文文本复述判别。使用单层的循环网络模型减缓由于网络层数过多加重的梯度消失和梯度爆炸问题,易于训练;并且利用外部记忆单元和语义角色知识帮助存储两句话中不同层级的语义联系。该文模型在英文评测语料Microsoft Research Paraphrase Corpus测试集上F值为84.3%。实验表明,语义角色标注知识确实可以帮助文本复述判别,并且轻量级模型达到了与同类多层次网络模型相近的效果。     

对象建模技术在信息系统中的应用

对象模型技术（OMT）是一种面向对象概念集以及与编程无关的图形表示法，包括对象模型，动态模型和功能模型，OMT在信息系统的分析与设计过程中具有很重要的作用，本文以辽宁省公路管理信息系统为例，利用OMT对公路管理信息系统中的国资管理子系统进行了详细的分析和设计，通过分析该子系统的三种模型，详细的说明了OMT在信息系统中的应用。     

基于OO技术图形编辑器的设计

一个基于OO技术矢量图形编辑器的设计方法,该编辑器具备矢量图形的创建、编辑、存储和导入等功能.     

Java中的Abstract Class与Interface技术研究

Abstract class和Interface是Java语言中对于抽象类定义进行支持的两种机制,正是由于这两种机制的存在,才赋予了Java强大的面向对象能力。Abstract class和Interface之间在对于抽象类定义的支持方面具有很大的相似性,因此很多开发者在进行抽象类定义时对于Abstract class和Interface的选择显得比较随意。但是,两者之间的区别还是很大的。文中从两者的定义、程序编辑、设计意图3个方面加以了比较。由此,对于它们的选择,反映出对于问题领域本质的理解和对于设计意图的理解是否正确、合理。     

基于力直方图的遥感图像中目标群间方位关系的建立

针对目标群间方位关系的建立,采用力直方图法,对所要处理的图像中目标群做一次全方位扫描,建立数据结构,可将各目标用于力直方图求解的有用信息一次取出,并建立目标群中各目标之间方位关系分布结构表示。最后,用多幅遥感图像验证了方法的可行性,证明了力的直方图法是一种用于表示目标间方位关系的有效方法。该方法一次可对多个目标进行处理,不必重复扫描,减少了计算量,便于对多个目标的把握,有效的掌握了目标群的整体分布特性,满足了同时对多目标图像处理的需求。     

Modeling spatiotemporal relationships between moving objects for event tactics analysis in tennis videos

Evolution of spatial relationships between objects often provides important clues for semantic video analysis. We present a symbolic representation that describes spatiotemporal characteristics and facilitates tactics detection based on string matching. To find typical spatiotemporal patterns of a targeted tactic, we organize training sequences as a tree, and effectively discover frequent patterns from the structure. Tactics detection is conducted by comparing a given test sequence with these frequent patterns. To realize the proposed idea, we develop elaborate audio/video processes to transform broadcasting tennis videos into symbolic sequences, and comprehensively tackle event detection and tactics analysis. We experiment on ten most important tennis championships in the year 2008, and report promising detection results on seven events/tactics. We demonstrate not only the effectiveness of the proposed methods, but also study the impacts brought by the results of tactics analysis.     

基于UML的MIS开发方法研究

本文对UML的建模机制作了系统的概述,然后以MIS的开发为背景,探索了基于UML的特定应用领域的系统开发方法及UML各图形之间的内在联系,说明了基于UML的系统开发过程是以用例为中心的开发方式。     

触发器在管理信息系统中的应用

本文对触发器的概念和功能作了详细的介绍,并针对 ＯＲＡＣＬＥ数据库,举例说明如何在信息 管理系统中应用触发器。     

虚拟环境中的虚拟目标摄像机实现方法

在漫游虚拟环境时,经常需要保持将视点固定在某个目标上,以便于对目标进行跟踪观察,实现这个视点变换功能的摄像机称为虚拟目标摄像机(VTC).可以使用面向对象技术,并结合OPENGL实现一类虚拟目标摄像机,完成对虚拟目标的跟踪,并可在此基础上实现任意视点变换,提供对目标的不同距离和任意角度观察.文章分析了目标摄像机的基本原理,并给出了一种软件实现.最终的实验结果表明,这种方法可以有效地完成目标跟踪,并可做到视点的实时变换,具有较好的可移植性,适用于不同的三维虚拟环境漫游.     

基于Oracle数据库OO4O技术的应用研究

OO4O(Oracle Objects for OLE)是Oracle公司提供的基于COM技术,能与Oracle数据库实现无缝连接和优化访问的一组编程对象的集合。介绍了OO4O的特点和使用方法,指出了直接使用OO4O存在的不足,利用面向对象思想把OO4O常用的操作封装成一个新类COO4ODB,并举例说明了该类的使用。