Interactive analysis and design of steel frames using the AISC specification

A number of computer programs are available for the analysis of frames and for the design, according to certain codes, of the individual members of such frames. This paper describes the integration of a plane frame analysis program and the American Institute of Steel Construction (AISC) column design program with interactive computer graphics to provide a complete system for the interactive analysis and design of steel building frames.The user of the program has the option of allowing computer controlled interation between analysis and design to produce a fully stressed design or he may select complete man-machine interaction for control of the analysis-design process. The use of interactive computer graphics displays aids the engineer in interpreting the large bulk of data needed for input and produced by the analysis and design algorithms.     

Applying interactive colour graphics in traffic planning

This paper considers the need for, and application of, interactive colour graphics in the planning and management of road traffic systems. It considers the use of computer models of road traffic networks and the advantages of graphics in displaying the distribution of traffic and its impacts over a study area. Examples are given of the use of interactive colour graphics in the four stages of model application: data input, model operations, output displays, and analysis of output data. The examples are taken from the study of a “local area” traffic network, and a range of alternative traffic management plans proposed and implemented in that area. Interactive graphics provides transportation engineers with the means to merge their needs for computer-based methods and models with their desires to use and produce maps and diagrams as a principal means of communication.     

Interactive graphics software for an undergraduate course in digital signal processing

The advantages of using a suite of computer programs developed to aid the teaching of undergraduate students in the principles and applications of digital signal processing are discussed. One particular interactive graphics program which displays z-plane diagrams and the related frequency response graphs is described and examples of the display presented. Some experience in using this software is presented.     

Data management for an interactive graphics system oriented to planning applications

INTRANS is a man-computer interactive graphics system, intended for analysis of urban and transportation planning problems. It is designed to operate primarily under time sharing on IBM 360/370 computers. The paper describes the functional design and the structure of the data management of INTRANS.

The data management is designed to answer the specific needs of planning applications: large data-sets, comparative analysis of several alternatives, and interface with batch processing computer programs. At the same time, the system is designed to operate within an environment of extremely limited resources of core and computing time.     

Initial equilibrium solution methods for cable reinforced membranes part II—implementation

This paper describes a portion of an interactive computer graphics design system which is devoted to the solution of the initial equilibrium problem for membrane structures. Real-time vector graphics displays are used to speed the preparation and display of structural data. A variety of solution methods is available to the designer to be used either individually or in combination. Examples of the use of each solution method and combined methods are included.     

Interactive 3D/2D visualization for geophysical data processing and interpretation

A new 3D/2D interactive display server was developed for the IGeoS geophysical data processing framework presented earlier. With introduction of this major component, the framework becomes conceptually complete and potentially bridges the gap between traditional processing and interpretation geophysical software.The display server utilizes Qt toolkit and OpenGL graphics libraries while taking advantage of the object-oriented design of the core data processing system. It operates by creating image object trees that are automatically propagated to the server(s) residing on the same or remote hosts and producing complex, structured, and interactive data displays. The displays support custom interactive graphical user interfaces, which are constructed entirely by the user and do not require computer coding. With over 200 specialized processing tools available, this approach allows creating 3D visualizations and building custom interactive data analysis, interpretation, and modeling tools in many areas of application. In particular, we show examples of integration of seismic ray tracing, gravity, and receiver function modeling and inversion in deep crustal studies.     

Computer graphics for building energy analysis

Two interactive computer programs, using extensive graphics, for the determination of thermal loads and other building characteristics are described. GOAL (General Outline Appraisal of Layouts) gives general input facilities and measures cost and performance attributes, including energy, at an early design stage, whilst the Environmental Systems Performance (ESP) model provides detailed energy analysis techniques applicable later in the design process. ESP consists of an input management section, a climate model, a dynamic thermal analysis module, and graphics output routines all linked by a common database. This paper discusses the use of graphics techniques in engineering software with particular examples from GOAL and ESP.     

Interactive computer methods for design optimization

Two interactive methods for design optimization are discussed in this paper. The first method is implemented by the computer program GDOPT and is an essentially manual search procedure based on graphical searches of the design space within user-defined planes. In contrast, the computer program ADOPT consists of the more effective nonlinear programming techniques available and the search is mostly under computer control. The user observes progress on a graphical display and is able to modify the search procedure as desired. These two interactive methods make an extensive use of computer graphics to display search results in the form of graphs, contour plots, sensitivity curves, and search trajectories. The designer interacts with the programs through these displays and is an active participant in the decision making process. It is believed that this integrated approach to design optimization can result in an enhanced understanding of the design problem and an effective convergence to the optimum design. An example is presented which illustrates the effectiveness of this interactive technique.     

An introductory computer graphics laboratory

Methods are described for teaching students how to write computer programs to perform basic graphics operations. The elementary operations of scaling, translation, reflection, shear, rotation and clipping are presented. Graphics 1000, a Hewlett-Packard graphics software product is the software used. This product imbeds subroutine calls in a FORTRAN program to execute the graphics functions. The laboratory sessions are divided into modules. Module I uses interactive programs to demonstrate graphics operations. Module II introduces Graphics 1000 commands. Module III uses interactive programs to demonstrate XY plotting with as many as four graphs per plot. Module IV uses interactive programs to demonstrate rotation of objects with hidden line removal. Students are assigned tasks ranging from drawing a section of an I beam through rotation of a three-dimensional object. Computer programs used for the demonstrations are available for the students to examine in order to learn how they work.     

Developments of CAD in civil engineering reviewed

Substantial progress has been made during the past decade in making the computer an effective analytical tool for the design engineer. However more recent development has concentrated on various features of a design offices final product. These areas comprise production of construction drawings, interactive graphics, colour graphics, pre-and post-processing of input and output data, linking analysis programs to modular design programs to provide a rapid transfer of design to the latest code requirement, use of microcomputers and personal computers. There is also significant software development for site management, cost analysis, general administration and documentation related to construction. This takes advantage of the availability of cheaper hardware which can communicate with other computers elsewhere in a network. User interaction facilities are being built into programs which allow the engineer to concentrate on design decisions. This paper reviews the developments during the last two-three years in CAD in Civil Engineering.     

Applications of Euclidean constructions to computer graphics

This paper presents an interactive graphics system called L.E.G.O. The purpose of L.E.G.O. is to model two- and three-dimensional objects using Euclidean geometry constructions. L.E.G.O. has a layered structure which makes it convenient to use, both for the experienced programmer and the novice. The programs may be written in a compiled language (C), written interactively in an interpreted language (LISP) or developed using a graphical interface in a multiple-window environment. Applications of L.E.G.O. include computer-assisted instruction of geometry and computer graphics, geometric modeling, and kinematic analysis. The use of imperative constructions and the powerful interface based on the idea of graphical programming are the most distinctive features of the system.     

The application of microcomputer and on-line graphical display technology to demand-responsive transportation services

Scheduling and dispatching a fleet of vehicles to respond to ongoing requests for transportation to and from various points in an urban area can be a complex proposition. Human controllers face an unmanageable number of scheduling possibilities. A strictly mainframe computer-based system would require elaborate computer algorithms, and high investment cost. This paper discusses the development of a low-cost interactive microcomputer color graphics system that displays vehicle and demand information and performs routine tasks while freeing the human dispatcher for creative decision-making. The system is designed for dispatching demand-responsive vehicles for pickup and delivery of passenger and express packages.     

PHIGS: A Standard, Dynamic, Interactive Graphics Interface

The Programmer's Hierarchical Interactive Graphics System (PHIGS) is a draft standard for computer graphics programming. PHIGS is useful for applications that manipulate complex displays of 2D or 3D data in a highly interactive environment. This is done through the hierarchical data organization and flexible editing capabilities provided in PHIGS. This article describes the goals and underlying model of PHIGS, reviews its capabilities, and provides some brief application examples. The similarities and differences of PHIGS and GKS are discussed.     

Xconf: A Network-Based Image Conferencing System

People often need to get together to share and discuss small amounts of image and textual data, but this is difficult when they are not located in the same place. One solution to this problem is Xconf, a multimedia computer conferencing groupware tool using existing national and international networks (the Internet). Simultaneous conferencing supports real-time interaction between multiple remote computer displays. Xconf multimedia may include conversational text, images, pointers to objects in images, and group execution of programs. Conferencing may take place with or without images. Interaction is tightly coupled with all users aware of global changes to the shared session and alternatively, individuals may monitor a specific subgroup of other users to concentrate on what they are discussing. Collaborative groups who have access to both computer networks and networked based X-Window System graphics displays can participate in a conference. Xconf is an X-Window "client" program which provides multimedia conferencing support for a group of X-Window displays. Because it is centralized, no software other than the standard X Window System is required on any of the participants display systems. Key data structures and algorithms for image conferencing are present.     

Practical computer graphics for scientific users: Philosophy and implementation

The scientific computer user presents a unique challenge to the graphics system designer. If the graphics system is properly designed and implemented, computer graphics becomes a vital research tool for the scientific user. These users' desires and expectations play an important role in every phase of the design process.This paper describes the philosophy of the graphics system at the National Center for Atmospheric Research (NCAR) and its implementation. Details of algorithms are not presented; rather the purpose has been to describe a successful computer graphics system which may serve as a guide for other designers who desire to provide practical computer graphics. This graphics system operates under a batch-mode computer system without using interactive terminals.     

Teaching elementary concepts in quantum mechanics with computer graphics

Students in a beginning quantum mechanics course worked with interactive computer graphics before being introduced to the formal structure of the subject. The computer programs and their use in teaching different concepts are described.     

Trade-off between resolution and interactivity in spatial taskperformance

Virtual reality displays usually lag far behind classical computer graphics displays in static image quality parameters, such as resolution. Both the popular press and scientific papers often stress that resolution will have to increase greatly before users can experience virtual environments as “the real thing”. Nevertheless, it is already possible to do some useful work in VR environments. The point we experimentally demonstrate here is that resolution is much less important for interactive tasks that employ immersive VR, where users can explore the environment by moving their heads and bodies, than it is in classical computer graphics applications, where users can only explore by gazing at a single picture. In the context of unmanned aerial vehicles, frame rate (read: passive camera movement) is more important than resolution for target detection, recognition, designation, and tracking. In the experiments reported here, we investigated the relative importance of various image parameters like spatial resolution (number of pixels per video frame), intensity resolution (number of gray levels per pixel), and temporal resolution (number of frame updates per second). Most experimental data concerning these resolutions come from classical psychophysics. However, experimental conditions in classical psychophysics feature stationary observers looking at short-term, pointlike flashes on stationary displays, and are thus far more representative of human interaction with pictures and photographs than with highly interactive systems like those employed in virtual reality     

Three-dimensional structural analysis using Interactive Graphics

Three-dimensional finite element structural analysis computer programs can only be used effectively when the input can be accurately generated and checked, and the output correctly examined. With the use of the Sandia Interactive Graphics System, SIGS, which consists of a cathode ray tube, a mini-computer, a CDC 6600 computer and an interactive graphics computer software system, both input and output can be effectively and efficiently processed.Examining three-dimensional objects is made practical by rotation of the object in real time with hardware and with hidden line removal. A computer program has been written with which the analyst can interactively supply and correct data to generate a three-dimensional mesh.Output processing is accomplished by describing planes which cut the three-dimensional object; then contour plots of outputted variables and deformed mesh plots are produced.     

Kinematics with computer graphics

The impact which computer graphics can have on engineering education is illustrated in this paper by considering the subject area of kinematics. Details of the mathematical modeling needed to support the generation of motion curves and computer graphics simulation for kinematic analysis are given, and a comparison is made with the current popular methods of analysis. Several results of computer graphic displays are given to illustrate the wide variety of situations where computer graphics can add to the teaching and understanding of kinematics.     

Graphics for data analysis

In recent years, graphics has become an essential part of modern data analysis. It is particularly useful for interactive data analysis. This paper describes a system called CLOUDS which is designed to make available on inexpensive storage tube terminals a wide range of graphics tools related to data analysis, economics, and management science. The system can be accessed nationwide by nonprofit organizations via the National Bureau of Economic Research computer network.