The GKS Input Model in Manifold

This paper describes the specification of the GKS input model in M anifold . The aim of the work reported in this paper was two-fold: first, to review the communication patterns implied by the GKS input model, and second, to evaluate the suitability of the M anifold language as a tool for defining complex dynamic interaction patterns that are common in non-trivial user interfaces.
The GKS input model is also adopted by all more recent ISO graphics standard documents. A more formal scrutiny of the inter-communication of the components of this model, excluding the implementation details of their functionality, is instructive in itself. It can reveal directions for improvement of its shortcomings and for generalization of its strengths for the ongoing effort to define the functionality of future graphics packages.
M anifold is a language for describing inter-process communications. Processes in M anifold communicate by means of buffered communication links called streams and by reacting to events raised asynchronously by other processes. Our experience shows that M anifold is a promising tool for describing systems of cooperating parallel processes. Our M anifold specification of the GKS input model offers a very flexible way to structure user defined logical input devices. Furthermore, it is simple and modular enough to allow easy extensions to include more functionality by local modifications. As such, it can serve as a basis for possible extensions and enhancements envisioned for future graphics packages.
1987 CR Categories: C.1.2, C.1.3, C.2.m, D.1.3, F.1.2, I.1.3, I.3.6, I.3.4.
1885 Mathematical Subject Classification: 68N99, 68Q10,68U05.     

C程序中如何正确地输入数据

C语言中,scanf 0函数可以用来输入任意类型的多个数据。在输入数据时,如果数据格式使用不当,就会使变量得呆到正确的值,从而使程序运行后得不到正确的结果。本丈对怎样使用输入格式才能够得到正确的输入数据进行了详细分析,以便掌握正确的数据输入方法。     

在VFP中如何使用NULL值

本文介绍了在VFP怎样使用NULL值来确定字段的值,NULL值在表中字段的使用方法。     

Guidelines for Determining When to Use GKS and When to Use PHIGS

GKS, GKS-3D, and PHIGS are all approved ISO standards for the application programmer interface. How does a system analyst or programmer decide which standard to use for his application? This paper discusses the range of application requirements likely to be encountered, explores the suitability of GKS and PHIGS for satisfying these requirements, and offers guidelines to aid in the decision process.     

如何使用JAAS技术实现J2EE中的安全

J2EE作为中间件技术史上的一块具有决定意义的里程碑,正受到业界越来越广泛的重视,相应地关于J2EE安全的研究也越来越广泛。本文简单介绍了J2EE框架和JAAS技术,着重讲述了标准JAAS安全如何使用一个简单的基于主题Subject和安全角色的用法模式实现J2EE自定义安全模型。     

如何用FactorySoft OPC Server Toolkit实现OPC数据访问服务器

本文介绍了一种简单方便的OPC服务器开发工具，并借用一个基于DeviceNet的OPC数据访问服务器的实例阐述了它的使用方法。     

如何用IDE卡替代主板上的输入输出接口

本文介绍了一种用IDE卡替代微计算机主机板上输入输出接口的维修方案，并例举出在四种主机板上实现这种方案的具体方法。     

议当前多媒体教学资源存在的问题及对策

多媒体教学资源是信息技术条件下师生教学过程的基础，本文在深刻分析了目前多媒体教学资源中存在的影响教学过程和教学效果的六个问题的基础上，提出了解决此问题的六个措施．对目前多媒体教学资源建设将会起到一定的保障作用。     

关于数据结构中出栈序列问题的讨论

在《数据结构》中,出栈序列问题是一个有趣的经典难题,至今还有很多文章讨论。在教学过程中,师生的共同探论可以为教学增添趣味,为实践增添成果,还可以为该经典难题提供更好的解决方案。该文给出了讨论过程中,学生提出的求解所有出栈序列问题的一些珍贵想法。     

The Formal Specification of Level la of GKS

In this paper the formal specification of a part of level la of GKS is given in the algebraic specification language OBJ. It shows that it is possible to produce a formal specification of a substantial part of GKS which is of manageable size and complexity specifying the appropriate level of abstraction of the system and using a suitable formal technique.     

如何用MiniGUI设计小键盘输入

MiniGUI是一种轻量级的针对嵌入式操作平台的图形用户界面支持系统,广泛应用于基于ARM、MIPS等主流嵌入式开发平台的项目及产品中.本文详细介绍嵌入式系统中人机交互常用输入设备(4×4数字小键盘)在MiniGUI中的实现方法,包括相关的底层按键扫描驱动程序,键盘输入引擎的编写,以及如何在MiniGUI中添加新输入引擎的方法等;最后针对调试过程中的典型问题提出一些调试建议.     

Are PHIGS and GKS Necessainly Incompatible?

The compatiblility issues that are of concern through the graphics industry are particularly serious in the relationship of GKS, GKS-3D, and nowcomer PHICS. The point made in this article is that PHIGS can be brought more into line with the GKS standards, offering a broader range of applications to both sets of users.     

The CONTEXT: a high-level structuring concept for GKS input

All human beings interact in some context or other. The concept of context has been explored by researchers in many different fields. A survey of some of this work is presented here. Using conceptual graph notation as a knowledge representation language, an introductory analysis of the concept of context and related notions is carried out and the results applied to GKS input. The outline of a possible implementation in Ada, with the (generic) package as the principal structuring unit and the task as the (low-level) implementation unit, is illustrated with a simple example.     

数据动态监测及可视化管理

本文设计系统软件实时监测保存在EXCEL表格中的动态数据,并对其进行可视化管理。以VC 6.0为开发工具,结合DDE机制和ODBC思想读取动态数据并构造数据库给以管理。同时,基于动态数据库和MapX控件构造地理信息系统对数据进行专题化显示。文章对其中涉及的关键技术、系统功能和开发步骤作了详述。