Semantic feedback in the Higgens UIMS

Almost all applications using interactive graphics contain important structures and concepts which are deeper than the geometres used to display them to the user. One of the major tasks of the system implementer is to cause the user interface to reflect this deeper structure accurately so that it may be directly manipulated by the user. The authors describe a tool, the Higgens user interface management system (UIMS), which can automate much of this task for a wide class of systems using interactive graphics. It is able to generate graphical user interfaces automatically from a high-level interface specification. These specifications are primarily nonprocedural in nature. They describe how graphical images can be automatically derived and updated based on applications entities, and how graphical inputs can be translated back into terms which are appropriate to the application     

Meaningful graphics workstation performance measurements

We present how graphics workstation performance is currently advertised by workstation manufactures. We suggest that the manufacturers' performance numbers are not the best indicators of how well the system will perform. Four levels of graphics system performance measurement have been defined by the NCGA Graphics Performance Characterization group[1]. These levels are low-level primitives (points, lines, and polygons per second), pictures, systems (input and action response times), and applications. We suggest that the best indicator of a graphics workstation's performance capabilities is that of an application running on the system. For applications level performance measurements, there are many potential applications from which to choose. We suggest that three-dimensional visual simulators are one of the better applications to study as that type of system has a realistic mix of processor and graphics computational requirements. We describe one such system, the Moving Platform Simulator (MPS), developed at the Naval Postgraduate School with the goal of fully listing its capabilities and utilized graphics techniques. We then present how that system performs on a currently available, high-performance graphics workstation.     

A Graphics System Architecture for Interactive Application-Specific Display Functions

Interactive computer graphics display requirements have generally been met is one of two ways: by highly specialized systems designed for a particular application, or, more frequently, by devices with a limited set of display functions common to a wide range of applications. A third alternative, presented here, is to use a high-performance, general-purpose display architecture to provide both common and application-specific graphics functions. A sampling data display to solid modeling, shows that significant improvements in interactivity can be obtained by microprogramming such a machine.     

On developing a GKS driver architecture for raster workstations

The use of raster graphics devices needs adapting to graphics applications. The first graphics standard, the Graphics Kernel System GKS, defines a logical interface on an application and device independent level. The workstation driver maps the logical GKS functions to device functions. First some special raster device facilities are outlined and then it is shown how to use them within the driver. To reduce the amount of driver implementations a common driver concept is sought here, especially for raster devices.     

Computer graphics in airport management

Computer graphics technology has been in use for over a decade. This technology has matured to a point where large applications involving databases can now be undertaken. This article describes the use of graphics technology in management of airport utilities, facilities and land. The systems described took over 60 manyears of development effort. This is considered as one of the largest and most complex undertakings in the application of computer graphics technology. As far as can be determined, no other airport in the world has a system of this size, complexity and sophistication. The events that led to a decision to develop the system are summarized. The system and how it is currently used at the airports within the Kingdom of Saudi Arabia are described.     

MATLAB技术在计算机实验教学中的应用

MATLAB是集数值计算、图形绘制、图像处理及系统仿真等强大功能于一体的科学计算语言。将MATLAB的图形绘制和系统仿真,数据处理等功能应用于计算机实验教学中,并进行实验更能使学生深入理解计算机相关理论与原理。该文首先介绍了MATLAB语言的特点、应用范围、各类工具箱及应用领域,详细论述了在实验数据处理中及基于MATLAB仿真技术在实验设计中重要作用,来提高学生在实验中的实际动手能力和创新能力。     

An approach to the formal specification of computer graphics systems

This paper discusses the approach to formal specification of computer graphics systems developed by the ANSI X3H3 committee (Computer Graphics Programming Languages) in the United States. ANSI's specification philosophy aims to gradually replace existing informal English language specifications with more formal ones without sacrificing the readibility and usefulness of standards documents. The specification techniques used are derived from those presently employed in the specification of computer communication protocols and the specification of software systems, not those used for the specification of programming languages. The specifications consist of three parts: the interface between both graphics and the host language and graphics and the graphical display device, the structure of the graphics system, and the functions that are performed by the graphics system. The specifications are based on abstract data types. These data types, together with the operations which can be performed on them, are used to describe the structure and functions of the graphics system. Using these techniques, X3H3 has developed a complete formal specification for a minimal graphics system. Extracts from this specification are included here.     

矢量图形编辑系统的数据模型及其实现

以电力行业为实际应用背景，本文提出了一组基于SVG的矢量图形编辑系统的数据模型，主要包括类结构、图元描述模型和SVG解析模型；同时，以该模型为基础设计和实现了一个独立于具体应用的矢量图形编辑系统，讨论了该系统的设计思想和体系结构，并对各部分功能进行了分析。     

Equalizer: A Scalable Parallel Rendering Framework

Continuing improvements in CPU and GPU performances as well as increasing multi-core processor and cluster-based parallelism demand for flexible and scalable parallel rendering solutions that can exploit multipipe hardware accelerated graphics. In fact, to achieve interactive visualization, scalable rendering systems are essential to cope with the rapid growth of data sets. However, parallel rendering systems are non-trivial to develop and often only application specific implementations have been proposed. The task of developing a scalable parallel rendering framework is even more difficult if it should be generic to support various types of data and visualization applications, and at the same time work efficiently on a cluster with distributed graphics cards. In this paper we introduce a novel system called Equalizer, a toolkit for scalable parallel rendering based on OpenGL which provides an application programming interface (API) to develop scalable graphics applications for a wide range of systems ranging from large distributed visualization clusters and multi-processor multipipe graphics systems to single-processor single-pipe desktop machines. We describe the system architecture, the basic API, discuss its advantadges over previous approaches, present example configurations and usage scenarios as well as scalability results.     

计算机辅助造船集成系统中的图形平台

计算机辅助造船集成系统二期工程ＣＡＳＩＳ－Ⅱ的图形平台，给设计人员提供了在产品概念上进行交互设计的图形环境，而不必理会点、线、圆等抽象的图形概念，对产品信息模型在大型应用系统中的实际应用和新型ＣＡＤ系统的建立作了初步的探索和尝试。文中叙述了船体结构产品信息模型，建立在这个产品信息模型上的图形平台的总体设计，基本功能和应用开发策略。     

A theoretical extension on the operational law for monotone functions of uncertain variables

The classical operational law of uncertain variables proposed by Liu makes an important contribution to the development of the uncertainty theory in both theories and applications. It provides a powerful and practical approach for calculating the uncertainty distribution of strictly monotone function of uncertain variables. However, the restriction on strictly monotone functions of the operational law limits its applications since many practical problems cannot be modeled by strictly monotone functions but general monotone functions. Therefore, an extension of the original operational law is needed. For this purpose, some properties concerning the uncertainty distributions of monotone functions of uncertain variables as well as the generalized inverse uncertainty distributions are presented first in this paper. On the basis of these discussions, a generalized operational law is proposed as a natural extension of the original operational law. Then the uncertainty distribution of a general monotone function of independent regular uncertain variables can be derived, which is analogous to the way that suggested by the original operational law for dealing with strictly monotone functions. Furthermore, as an application of the generalized operational law, a theorem for calculating the expected values of general monotone functions of uncertain variables is presented as well.     

A Library for Developing PHIGS Programming Tools in a PEX Environment

The merger of three-dimensional graphics with the X Window System has recently been standardized by adapting PHIGS, the Programmer's Hierarchical Interactive Graphics System, to the X Window System with PEX, the PHIGS Extension to X. The standard programming library for PEX has been defined to be identical to PHIGS PLUS allowing PHIGS programs to port directly to the X environment. X uses a client server model to run applications as client processes which communicate with a server to perform graphical display and input. For improved performance, the PEX extension defines new server resources to reduce network traffic and to take advantage of graphics hardware existing on high-end servers. A side effect of this distributed model of computation is a distribution of PHIGS structures leading to a relaxation of the exclusive access which a PHIGS application usually maintains over its Central Structure Store. We exploit the distributed nature of a PEX/PHIGS client's Central Structure Store to provide access to it for other applications besides the originating PEX/PHIGS client. We refer to these other applications as tools since one of our primary goals is to create development tools for PHIGS programmers. Rather than concentrate on particular debugging tools, we focus upon easing the process of actually developing tools. Our goal is to supply a collection of routines which can be used by PHIGS programmers to create custom tools or other programs which require access to the graphics data of remote PHIGS processes. Our Tool Development Library provides the PHIGS programmer a small number of management routines which orchestrate the connection and mapping to the data of one or more remote PHIGS applications. Manipulation of remote PHIGS structures is accomplished just as easily as local operations and is performed using standard PHIGS calls. The remote application being accessed requires no changes to its source code. Obvious uses for the Tool Development Library are in the construction of PHIGS tools such as structure browsers, editors and debugging aids. Less obvious is the potential for developing collections of cooperating graphics applications which share graphics data.     

A VLSI Implementation of the Graphics Standard GKS

The main advantage when using a standardized graphics system is quite obvious: the application programs become portable. Integrating such a system - and GKS (Graphical Kernel System) is the only one being standardized internationally - into VLSI (Very Large Scale Integration) chips, this graphics system may become an integral part of graphical devices. This guarantees a uniform interface of such devices to GKS applications. Devices of many different kinds will become compatible not only with respect to plugging but even in their logical behaviour, eliminating all device dependencies from the host software.
We have started to design the GKS-chip which will be able to be used in a great variety of devices (vector and raster type). The GKS-chip will bring the computational power to support real time picture updates, limited only by the maximally attainable output data rate.     

基于“广义形体分析法”的高职图学课程改革探索与实现

“广义形体分析法”是“工程图学”课程改革的一种探索性创新思维方法,它 将课程核心内容整体分解为几何元素、几何结构、功能组合、零件装配、知识与技能等5 个 块元。介绍了基于“广义形体分析法”的高职“工程图学”课程改革方案及其实现关键,进行了 改革的初步探索和实践,取得了较好的成效。实践结果表明,该方法能有效提升图学基础与 应用的教学效果,有助于职业快速适应、逻辑思维形成及创新能力提升。     

Adding graphics to a high-level programming language

When graphics input/output capabilities are added to a programming language originally designed with a text stream input/output model, various design decisions affect the ease with which the graphics facilities are learned and used by applications programmers. In adding window system facilities to the Icon programming language, some design decisions were made very differently from the conventional wisdom, resulting in substantial benefits for programmers. In addition, some pre-existing Icon language features have proved to be useful in graphics programming.     

Graphics by a Logic Database Management System

The GEDBLOG system allows applications which manipulate graphic objects to be developed following a declarative definitional style. GEDBLOG supports the consistent design and prototyping of graphic applications through an incremental development and makes it possible to guarantee automatically that the application meets its specifications. Typical GEDBLOG applications have graphics as their characterizing element and can be found, for example, in the CAD/CAM, visual languages or graphical interface areas. The system is obtained by integrating a graphical data language in an existing logic database management system, EDBLOG, so that graphic and non-graphic information is handled in a uniform declarative way.     

3Gmap L-systems: an application to the modelling of wood

In this paper an extension of L-systems is proposed, based on three-dimensional (3D) generalized maps that allow an easier control of the internal structure of 3D objects. A first and original application of this extension is also proposed: wood modelling by growth simulation. Numerous other applications of our work are possible, in the area of computer graphics, as well as in botanical science.     

The application visualization system: a computational environmentfor scientific visualization

A software system for developing interactive scientific visualization applications quickly, with a minimum of programming effort, is described. This application visualization system (AVS) is an application framework targeted at scientists and engineers. The goal of the system is to make applications that combine interactive graphics and high computational requirements easier to develop for both programmers and nonprogrammers. AVS is designed around the concept of software building blocks, or modules, which can be interconnected to form visualization applications. AVS allows flow networks of existing modules to be constructed using a direct-manipulation user interface, and it automatically generates a simple user interface to each module     

基于WebServices和MobileSVG的移动数学查询系统的设计

文中从方便学习者使用异构移动终端进行数学公式及图形查询的角度出发,设计了一种基于WebServices四层架构的移动数学公式及图形查询系统。该系统的服务端使用J2EE开发,客户端使用J2ME开发,以支持学习者通过不同分辨率、不同操作系统的移动设备查询常用公式、函数及图形,另外,该系统还使用MobileSVG技术生成矢量数学图形,并将Ajax、gzip等技术用于提升性能,能大大提升查询速度、节省移动客户端的有效存储空间。该系统的架构和所采用的技术克服了目前移动设备访问网络资源速度较慢、存储量较小、分辨率不同等各种影响学习效果的不利因素,因此能为学习者提供更好的移动数学学习支持。具有很好的应用价值。     

Multilevel picture segmentation in the graphics system—GRASP

Multilevel graphics structures are highly suited for interactive applications of computer graphics. The facilities concerning the semantics of picture naming and structuring provided by a graphics package are highly influenced by the ease of implementation and operational requirements. This paper presents a multilevel graphics structure provided by GRASP—A 3D Graphics Systems for Pascal users. Picture segmentation commands provided by GRASP allow pictures to be hierarchically structured as collections of sub-pictures which themselves are collections of instances of predifined picture segments. Complex changes in a picture can be effected by commands which allow modifications of graphical entities at specified levels in the picture hierarchy. An edited sub-picture can be redefined as a segment to allow restructuring of the picture hierarchy. The implementation of the scheme presented here has been facilitated through the use of dynamic data structures composed of pointers and records. Powerful error reporting functions aid the programmer considerably in detecting errors if any. A garbage collection scheme conserves working memory space. A couple of applications described at the end of the paper illustrate the flexibility provided by the scheme.