基于XML的石油勘探数据库查询应用系统的实现

通过XML技术在河南油田勘探数据库查询应用系统中的应用,提出了XML技术和数据库技术相结合的数据库快速灵活地查询浏览应用的解决方案。在该方案中,以XML为数据交换标准,采用了多级分布式三层架构,很好地实现了数据库查询应用系统的开放性和可扩充性。     

Informix多数据库共享同一数据表的方法

在建立数据库应用系统中,经常遇见这样的情况:多个数据库共享同一数据表的数据。在Informix数据库管理系统中,我们以往常用的方法是,对公共数据库表建立一套完整的数据库管理模块,在各个应用系统中分别嵌入对这些模块的调用,这样,运行过程中,应用程序常需要在多个数据库之间不断切换,增加了系统开销,降低了系统效率。同时,对于使用了游标的数据表,若在同一个模块运行中涉及多个数据库游标的交叉调用,则会出现错误。另外一个方法是,在应用数据     

基于Oracle数据库应用系统的容灾性分析研究

该文针对Oracle数据库应用系统,对容灾技术的技术指标、分层标准、保护级别进行了分析,以Oracle数据库应用系统为基础,研究了Oracle数据库应用系统的容灾性,并以此为基础,设计了Oracle数据库容灾技术在计费系统,报名系统和医疗系统中应用的解决方案,并对个中容灾性关键问题的处理给出了基于Oracle数据库应用系统的应对模式。     

基于Java的数据库连接池技术在即时通信系统中的应用

介绍了基于Java的数据库连接池的访问机制,并以即时通信系统为例,展示了数据库连接池能很好地应用在对数据库访问频繁的数据库应用系统中,使数据库连接得到了高效的,安全的复用,大大提高了系统的复用性和交互性,提高了对数据库的访问效率。解决了系统性能的瓶颈问题,从而大大提高了系统的性能。     

虚拟维修训练系统中数据库的应用

数据库技术在虚拟维修训练系统中起着重要的作用。文章以MySQL数据库为例简述了数据库特点,分析了应用数据库的虚拟维修训练系统的优势,介绍了虚拟维修训练系统中数据库设计的基本方法,结合Torque Game Engine三维引擎开发了具有较好可移植性的虚拟维修训练系统。实验结果表明,将数据库技术应用到虚拟维修训练系统,可以有效提高系统开发的效率。     

基于分布式数据库系统的监控系统的开发模型及其实现

分析了在目前监控系统开发中数据库应用面临的普遍问题,从实际应用的角度出发提出了在监控系统开发中数据库应用开发应该遵循的原则并通过比较提出了适应用户需求的一种数据库应用开发模型,最后结合作者的开发产品的实例进行了说明。并对数据库系统适应当前应用的发展方向作了展望。     

浅谈在局域网中数据库应用系统的开发

当今时代数据库应用系统已经广泛地应用于各行各业的管理工作中,发挥着较为重要的作用。本文首先阐述了数据库应用系统的特点,其次,探讨了数据库应用系统未来的发展方向,同时,分析了局域网中数据库应用系统的构建。最后以高职院校毕业设计选题管理系统为例进行实例分析,具有一定的参考价值。     

数据库虚拟机模型的分析与研究

在企业进行数据库相关的开发和应用中,常常因为数据库结构的变化而导致应用系统出现异常.企业不得不针对数据库结构的变化而修改所有相关应用系统,造成人力和资源的极大浪费.文中提出一种数据库虚拟机的框架模型,根据抽象与实际相分离的原理,实现了应用系统和数据库之间的相互独立;从而降低了应用系统维护的工作量,使系统有更强的自适应性.作为一个完整的框架模型,虚拟机对数据库中的同名异义,同义异名等问题都进行了处理,并在一定程度上解决了数据冗余.     

新闻发布系统的数据库建模和系统实现

本文介绍了一个典型的新闻发布系统数据库的建模和系统实现，重点是其数据库的逻辑建模，以及ERA模型在逻辑建模中的应用。在建模过程中，应用了数据库规范化理论，减少了冗余数据，提高了系统的可维护性。最后，简要说明了建立在数据库建模基础上的系统实现。     

基于Web Service的异构数据库同步系统设计与实现

针对在分布式网络环境下异构数据库之间数据同步中存在的问题,提出了一种基于WebService技术的异构数据库数据同步系统的解决方案和实现方法。通过在各数据库应用系统中放置基于WebService技术的数据同步客户端程序以及在服务器端部署WebService服务程序实现数据的同步,不但有效地解决了在异构数据库之间数据同步时存在的问题,而且对各需要同步的应用系统的正常业务处理几乎没有影响,对应用系统的改动工作量也很小。最后,把该方案应用到了一个实际项目中。     

Reasoning about Qualitative Spatial Relationships

In this paper, we consider various spatial relationships that are of general interest in pictorial database systems and other applications. We present a set of rules that allow us to deduce new relationships from a given set of relationships. A deductive mechanism using these rules can be used in query-processing systems that retrieve pictures by content. The given set of rules is shown to be sound; that is, the deductions are logically correct. The rules are also shown to be complete for three-dimensional systems; that is, every relationship that is implied by a given consistent set of relationships F is deducible from F using the given rules. In addition, we show that the given set of rules is incomplete for two-dimensional systems. We also present efficient algorithms for the deduction and reduction problems. The deduction problem consists of computing all the relationships deducible from a given set, while the reduction problem consists of computing a minimal subset of a given set of relationships that implies all the relationships in the given set.     

A Legal Ontology Refinement Support Environment Using a Machine-Readable Dictionary

This paper discusses how to refine a given initial legal ontology using an existing MRD (Machine-Readable Dictionary). There are two hard issues in the refinement process. One is to find out those MRD concepts most related to given legal concepts. The other is to correct bugs in a given legal ontology, using the concepts extracted from an MRD. In order to resolve the issues, we present a method to find out the best MRD correspondences to given legal concepts, using two match algorithms. Moreover, another method called a static analysis is given to refine a given legal ontology, based on the comparison between the initial legal ontology and the best MRD correspondences to given legal concepts. We have implemented a software environment to help a user refine a given legal ontology based on these methods. The empirical results have shown that the environment works well in the field of Contracts for the International Sale of Goods.     

UML元模型图实例自动生成算法

UML元模型建模与实例生成是软件自动生成技术的重要环节之一,相关理论和技术在领域建模语言DSL中得到广泛应用.元模型自动生成实例技术不仅可以降低软件开发难度和成本,还可以提高软件开发效率.在已有元模型实例生成图语法理论的基础上,提出相应的元模型图实例自动生成算法,证明了该算法与图语法的等价性.并且在可视化UML建模平台中实现了这一算法,得到了从UML元模型自动生成大量实例的预期结果.     

一种G2连续的二次曲线样条插值方法

给出了一种用二次曲线段来插值平面有序数据点列的一种方法 .文中的曲线采用隐函数表示而不是常用的参数形式 .曲线不是用通常的二曲线方程来表示 ,而是用一种带参数的函数样条来表示 .首先给出用二次曲线来插值两点、两切线以及在一端点处的曲率达到给定值 ;其次 ,给出了用二次曲线样条插值平面上一个有序点列且使曲线达到整体 G2 连续 ;最后就用二次曲线对平面闭曲线插值问题进行了研究 .该方法对数据点列没有任何限定性要求 ,无论是闭曲线还是开曲线 ,都能达到整体 G2连续 .     

状态空间模型下的Hammerstein系统的递推子空间辨识方法

一般来说, 单输入单输出情形下的Hammerstein系统可以由转移函数来表示, 而对于多输入多输出情形下的系统其输入与输出间的关系难以表示. 本文基于Hammerstein系统的状态空间模型, 研究了其子空间辨识方法. 在开环情形, 对Hammerstein系统给出了在其非线性函数可以由有限基函数线性表示的情形的子空间辨识方法, 及其递推实现. 并且初步分析了这些方法的渐近性质. 针对这一方法, 我们给出了一个数据模拟实例分析方法的优劣.     

Entrophy Layers

The entropy layer on a blunt-nosed cone is analyzed, in view of the difficulties it produces in numerical computations. A rule is given to determine at what distance from the nose the entropy layer is a given fraction of the shock layer, for a given free stream Mach number.A simple and very efficient way of computing flows with strong entropy layer effects is given. It is essentially based on the insertion of a line representing a locus of rapid changes in entropy derivatives, and on forbiding certain differentiations across such a line.     

The synchronization of linear systems under quantized measurements

This paper studies the synchronization of high order linear systems in the presence of quantized relative state information. Using the Lyapunov method and non-smooth analysis, it is shown that when a uniform quantizer is used, the original multi-agent system can reach finite-time practical synchronization under the given communication protocol. It is also pointed out that when a logarithmic quantizer is considered, the given systems can reach synchronization under some conditions. The obtained results generalized the existing results of single integrator systems and double integrator systems. Numerical examples are given to illustrate the given results.     

A sequential approach for unconstrained optimization via a partitioning technique

In this paper, an alternative optimization strategy incorporating the ideas of lexicographic optimization and evolutionary algorithms is presented. The given optimization problem is approximated by others in which priorities are given. Under the sequential optimization method, they are optimized, not exhaustively, in order to produce an initial point for the given problem. An important role in the proposed approach plays the way of generating the involved problems and the given priorities on them. General principles to produce the objective functions of the involved problems are proposed. An algorithm named LexOpt Algorithm, which implements the suggested process, is given. Numerical results via LexOpt Algorithm, on a set of widely used test problems show noticeable promising convergence behaviour of the proposed strategy in comparison with the utilized optimization methods.     

Think globally, act locally: decentralized supervisory control

Decentralized supervisory control is investigated by considering problem formulations that model systems whose specifications are given as global constraints, but whose solution is described by local controllers. A necessary and sufficient condition is given for the existence of a solution to the problem of finding decentralized supervisors that ensure that the behavior of the closed-loop system lies in a given range. Where the range of behavior can be described by regular languages, it can be effectively tested whether the decentralized control problem is solvable; in this case, a procedure is given to compute the associated supervisors     

VHDL语言在FPGA中的应用

本文讨论了用VHDL语言进行FPGA设计的方法,简单介绍了VHDL语言的基本概念以及FPAG的设计流程,并举例说明了如何编写可综合的VHDL代码,使用Altera公司的MAX+PLUSII10.2开发软件进行功能仿真并给出仿真波形。