FOXPRO2.5系统程序设计讲座(二)

第三讲.备注字段和通用字段 Foxpro系统对数据库结构的突破性改进是:大大丰富了备注字段Memo的使用能力;并为提高对多媒体数据处理能力,Foxpro for Window新增了一个通用型字段General。 一、Foxpr02.5的备注字段 FOX系列数据库系统都提供一个备注型字段MEMO,作为一个基本的数据类型。然而,在Foxpro产品出现以前,备注字段由于其操作的不灵活性,一直不受人们的重视。     

FoxPro备注字段的格式输入与输出

从ＦｏｘＰｒｏ提供的备注字段的操作函数和命令开始，通过例子程序介绍了在ＦｏｘＰｒｏ中备注字段的格式输入和输出     

FoxPro备注字段的新特点及其编程技巧

1、引言 FOX系列对数据库结构都提供一个备注型字段MEMO,作为一个基本的数据类型。然而,自FoxPro产品出现以前,备注字段由于其操作的不灵活性,一直不受人们的重视,有时宁可浪费存储空间而使用定长的字符型字段。 FoxPro 2·5以上版本对备注字段的存储能力与使用操作方面作了很大的扩充,并保持了与以往FOX产品的备注字段的兼容性,从而使备注字段作为一种强有力的数据类型为我们提供了灵活的编程手段。     

FoxPro备注文件结构剖析

备注字段可以存放各种不同长度的文字,例如,附记、注解、记号和特殊指示等。一个字段最大可以到64KB字节,它的最大特点是不必事先定义大小,这个字段可以在编辑或者处理时,根据需要增大而变大,实际上是一个可变长字段。在以往的dBASE家族中也有备注字段,但是没有得到很好的应用,原因是使用不甚方便。而PoxPro对备注字段的处理提供了大量的函数和命令,例如在Clipper中,要解决备注文件的垃圾压缩问题,需要设计一个非常大的C程序来进行加工,而在FoxPro中,一个命令就解决问题。为了对备注文件使用得更深入,本文试图通过一个具体实例来剖析备注文件的内部结构,同时,     

FoxPro备注字段处理命令及使用技巧

从实用的角度出发，将ＦｏｘＰｒｏ中可用于备注字段处理的命令分类，并详细介绍各命令的功能和使用技巧，最后给出一个备注字段处理的实例。     

用汇编语言处理FOXPRO数据库备注文件的方法

在显示和打印FoxPro数据库的备注文件时，由于不便进行格式控制及会破坏原有屏幕等问题，使操作者和程序员感到不便。作者通过对数据库结构的分析，用汇编语言编制了读取备注字段的程序，从而解决了这一问题。我们知道，若数据库有N个字段，则数据库结构部分共有（N＋1）*32＋1个字节，其中第一个块（3个字节）为数据库总体描述，第i块（i=2，3，……N＋1）描述第i—1个字段的定义，包括字段名、类型、长度、小数位数，字段起始位置等参数；备注型字段，在数据库中是一个10字节长的指针项，每一字节为一位数字的ASCII码。备注文件实际上…     

VFP系统中数据表备注字段文件的探密

本文通过对数据表中备注文件的分析,介绍了备注文件的存储方式、备注块大小的定义,提出了备注字段内容的输入输出方法。     

改进对dBASEⅢ库文件备注字段的修改

在dBASEⅢ的库文件(扩展名为·DBF)中,备注字段的修改不在于修改过程本身,而在于存贮空间的浪费。这是因为,备注字段的实际内容是存放在备注文件(扩展名为·DBT)中的,在备注文件中,存贮空间以块为单位,每块长512字节。而库文件中的备注字段内存放的是一个指针,指向其实际内容在备注文件中所占用的块。当修改备注字段的实际内容(哪怕只改一个字符)后,dBASEⅢ就将新的备注内容存入一个新块,原块就衩抛弃而永不再用。显然,     

MS PASCAL直接访问dBASEⅢ备注字段的方法

本文对如何用高级语言直接操作DBF文件的备注型(M)字段作了有益的探讨,实现了MS PASCAL直接访问dBASEⅢ数据库DBF文件的备注字段。     

显示备注型字段的新方法

本文介绍了一种显示备注型字段内容的新方法,能够在屏幕的某块区域内进行分页显示,解决了备注型字段不能格式化输出的问题,具有一定的推广价值。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。