Interactive Graphics System Research Articles

An efficient flood-filling algorithm

Flood-filling of a region on raster devices is one of the most widely used techniques in the interactive graphical systems. Existing filling algorithms, in general, require significant amount of memory and/or are limited to the specific types of regions or fill styles. We discuss some of the up-to-date filling techniques and propose a general framework for generation of flood-filling algorithms. An “optimal” representative of this class of algorithms is presented. It is proved, in particular, that necessary size of work memory for this particular algorithm is proportional to the horizontal dimension of the box containing region to be filled. The algorithm may be used to fill 4-step and 8-step connected regions both border- and interior-defined.

An Interactive Graphics System for Real-Time Investigation and Multivariate Data Portrayal for Complex Pedigree Data Systems

GRIFFIN ( graphics investigation of familial in formation), an interactive graphics system for exploratory investigation of data on individuals associated by familial relationships, was designed to provide genetic epidemiologists a flexible, rapidly responsive tool for viewing and guiding exploration of complex databases in the context of familiar pedigree structures. It graphically portrays both categorical and multivariate scalar data on individuals in those structures. The display can be inverted to show all ancestors and descendants of any individual the user designates. It provides cues to censored information when bushy pedigrees cannot be fully displayed without sacrificing legibility. These guide users on where to next invert the system. Investigators may translate/zoom the display, vary the mode of representing data, point to individuals to obtain displays of alphameric information about them, etc. Developed in Fortran using IBM's GDDM graphics subroutines for an IBM 3090 mainframe, GRIFFIN's design anticipates porting to smaller systems.

Analog input device physical characteristics

When selecting a device, a designer should compare alternative devices point-by-point. When making a tentative decision, one needs to know what other possibilities have been locked out. A classification graph does this.New here is this classification graph. Also new are several terms: free, sticky, unbounded, bounded, homogeneous and volatile. We developed this classification of existing devices while building the GRIP-75 interactive molecular computer graphics system [2, 11] and refined the classification during discussions with other system builders where we used this classification to map out alternatives. This paper is founded on practice and experience, not on classification theory.

Visually controlled graphics

Interactive graphics systems that are driven by visual input are discussed. The underlying computer vision techniques and a theoretical formulation that addresses issues of accuracy, computational efficiency, and compensation for display latency are presented. Experimental results quantitatively compare the accuracy of the visual technique with traditional sensing. An extension to the basic technique to include structure recovery is discussed. >

PsyScope: An interactive graphic system for designing and controlling experiments in the psychology laboratory using Macintosh computers

PsyScope is an integrated environment for designing and running psychology experiments on Macintosh computers. The primary goal of PsyScope is to give both psychology students and trained researchers a tool that allows them to design experiments without the need for programming. PsyScope relies on the interactive graphic environment provided by Macintosh computers to accomplish this goal. The standard components of a psychology experiment—groups, blocks, trials, and factors—are all represented graphically, and experiments are constructed by working with these elements in interactive windows and dialogs. In this article, we describe the overall organization of the program, provide an example of how a simple experiment can be constructed within its graphic environment, and discuss some of its technical features (such as its underlying scripting language, timing characteristics, etc.). PsyScope is available for noncommercial purposes free of charge and unsupported to the general research community. Information about how to obtain the program and its documentation is provided.

The design of microworlds in geometry based on a two‐dimensional graphics system devised for secondary education

Interactive graphics systems for geometric construction at school allow the teacher to design microworlds in which the graphic‐constructional competencies of the student can be qualified ('reduction of the graphic‐constructional barrier'). Ideal typical possibilities of the design are given by the modification of the menus and by the supply of graphic‐constructional finished or semi‐finished products for a direct manipulation or completion. Microworlds designed with the Cabri‐Geometre for the secondary level I are presented, which adapt the tool to learning groups and to constructional‐geometric complexes of problems as well as to single problems.

AXIOM: the scientific computation system

Recent advances in hardware performance and software technology have made possible a wholly different approach to computational mathematics. Symbolic computation systems have revolutionized the field, building upon established and recent mathematical theory to open new possibilities in virtually every industry. Formerly dubbed Scratchpad, AXIOM is a powerful new symbolic and numerical system developed at the IBM Thomas J. Watson Research Center. AXIOM's scope, structure, and organization make it outstanding among computer algebra systems. AXIOM: The Scientific Computation System is a companion to the AXIOM system. The text is written in a straightforward style and begins with a spirited foreword by David and Gregory Chudnovsky. The book gives the reader a technical introduction to AXIOM, interacts with the system's tutorial, accesses algorithms newly developed by the symbolic computation community, and presents advanced programming and problem solving techniques. Eighty illustrations and eight pages of color inserts accompany text detailing methods used in the 2D and 3D interactive graphics system, and over 2500 example input lines help the reader solve formerly intractable problems.

Animated simulation of the robot process capability

This paper describes an interactive computer graphic system developed for simulating robot capability. The system determines the positioning repeatability and accuracy of a robot performing specific operations. Central to the system are three characteristics, information describing the errors of the geometric and kinematic parameters of a robot, a common function to request and display a robot moving from one position to another, and finally a family of charts showing the repeatability of the robot implementing a given task.

Integrating Microgravity Test Data with a Human Computer Reach Model

Future space vehicles such as the Space Station Freedom will be equipped with computers that have direct manipulation capabilities. The human factors challenge is to provide an optimal human-systems interface which will accommodate a wide range of users and tasks in a microgravity environment. A series of experiments have been conducted by the Man-Systems Division at Johnson Space Center to resolve anthropometric issues related to human reach capabilities and limitations impacting workstation design. To facilitate this goal, two approaches, “Performance-based” and “Model-based” analyses, were integrated to investigate the human reach mapped onto the workstation display panels. Microgravity maximum reach sweep data were collected onboard NASA's KC-135 Reduced Gravity Aircraft. A three-dimensional (3-D) interactive graphics system, PLAID, was used to generate anthropometrically correct human computer models. Video tapes recorded during the flights were used to extract information for positioning each human representation in the computer model relative to the workstation. The approach, findings and implications of the evaluations are discussed in the paper.

Application of image analysis for evaluation of red blood cell dynamics in capillaries

We have devised a method to display and directly evaluate red blood cell (rbc) dynamics in capillaries using the same dual camera intravital video microscopy system employed to determine rbc oxygen saturation (Ellis et al., 1990). Capillary images are recorded on videotape and an interactive graphics system is used for analysis. Data are sampled once a frame for 60 sec using a window (one pixel wide (0.93 μm) and 100 pixels high) positioned along the axis of a capillary. The resulting data are displayed as sequential space-time images 100 pixels high by 300 pixels wide (10 sec). The space-time images thus created represent the dynamics of the rbc's in a single comprehensive static image in which the rbc's appear as dark, diagonal bands separated by light bands representing plasma gaps. From these images one can obtain information on velocity of individual rbc's (μm/sec), lineal density of rbc's (rbc/mm), and rbc supply rate (rbc/sec). This information can be used to delineate the temporal and spatial heterogeneity of hemodynamics in capillary networks. These data can then be combined with coincident data on red blood cell oxygenation to provide a complete picture of oxygen transport in capillaries or it can be used alone as a tool for the evaluation of basic in vivo and in vitro rheological questions.

3D layout manipulation functions with a glance to optimization problems

APL syntax provides a very simple and expressive way to generate and manipulate simple 3D parametric objects. APL2 nested arrays provide powerful data structures for a compact, readable and executable description of 3D layout scenes. The paper describes a user-friendly interactive graphic system for 3D layout manipulation. The user can define and modify a layout scene by graphical interaction on a 3D perspective projection. User's commands enable change of parameters, 3D transformations and friendly operations that involve position relationship between objects. Commands are translated into “messages” to graphic objects, and the result of the operations is immediately reflected in a modification of the “scene data structure”. The system includes the capability to select objects from a catalogue, to build compound objects and to edit sub-objects. The scene data structure is well suited for interface to external graphics rendering programs. Data structure can be extended to include non-geometrical information. Moreover it is possible to apply complex numerical algorithms to geometrical and numerical data. A heuristic algorithm for Satellite Systems Layout Optimization is presented as an example.

Development of interactive biomolecular graphics system LIVE

Development of interactive biomolecular graphics system LIVE

A fire field model implemented in a parallel computing environment

AbstractThis paper describes the implementation of a fire field model in the parallel computing environment offered by multiple transputers. The fire model is built into the general purpose SIMPLE‐based CFD code HARWELL‐FLOW3D. The technique of domain decomposition has been applied tb convert the conventional serial version of FLOW3D into a code capable of efficiently utilizing an arbitrary number of transputers. Fire simulations consisting of up to 24 000 computational cells are performed on parallel systems with up to 15‐processors. The run time for this simulation has been reduced from over 4 days on a single processor to just over 8 h on the 15‐processor system. An interactive graphics system has also been developed which runs in parallel with the main computations.

Fire-field modelling on parallel computers

Practical fire-field modelling demands considerable computer resources. This insatiable demand for computer power limited the practice of field modelling to those organisations which had access to expensive computers and applications which could justify the expense. Parallel computing techniques offer the potential of achieving the power required at a fraction of the cost of conventional computer systems. In this paper the development of a fire-field model which has been designed to utilise an arbitrary number of processors operating in parallel cs described. In the implementation discussed here, the processing elements are transputers and the host computer is a 386 based personal computer. However, the adopted approach is not restricted to this particular parallel computing hardware configuration. The capabilities and potentials of the parallel system are demonstrated by performing fire simulations consisting of up to 24 000 computational cells on parallel systems with up to 15 processors. The run time for this simulation has been reduced from over 4 days on a single processor to just over 8 h on the 15 process or system. An interactive graphics system has also been developed which runs in parallel to the main computations.

Customized systems for engineering applications

An APL™-based high-productivity software-development environment is shown to enable small teams of two or three persons to build complex engineering software systems. The productivity and flexibility of such small teams, equipped with this environment, enables them to build customized engineering application systems economically. These customized systems are far more useful for the particular applications they address than are the generic systems that are commonly produced by large software-development groups. A customized engineering application system is described, illustrating the productivity of the two APL2-based computer-aided software engineering (CASE) tools used for its implementation and long-term software maintenance. The system is presented in some detail, to demonstrate its sophistication and thus provide a measure of the productivity of the software-development environment. The two CASE tools that comprise this software-development environment are used to build interactive graphical application systems, and to build systems for applications that require or can benefit from distributed cooperative processing. A list of some customized application systems built using the described environment is provided, along with estimates of the implementation efforts. The features of APL2 that play a key role in the effectiveness of these tools are also discussed.

A Parametric Design Method for Computer-aided Design of Electric Machinery

SUMMARY In this paper the basic ideas behind an original computer-aided design (CAD) system for designing electric machinery is described. The framework in which all modules are implemented is a powerful interactive graphics system. The user thus continuously maintains control over the entire design through graphical communication. Because the CAD system is essentially conceived as a closed loop process, it supports a flexible and progressive design, allowing many trials-and-errors. Basically, the CAD system comprises two nested loops. In the outer loop, the adaptive modelling process, the geometry of the machine is controlled. The resulting geometric model maintains a dual representation of the machine. The boundary representation accepts all graphical actions of the interactive drafting system and guarantees compatibility with external systems through standards. The material region representation, on the other hand, is required for the purpose of calculation. The geometric model is hierarchically organi...

Optimal design with the aid of randomization methods

Many design problems can be formulated in terms of a number of nonlinear equations and inequalities. A solution of such equations is called a design. In the present paper a method is given for the random generation of a large number of designs, which can be ordered according to some criterion. Using highspeed computer calculation, a large number of random designs is generated from which the designer can make a choice. A trend in selecting certain designs can be imposed: A requirement can be optimized or an optimal compromise between two or more conflicting requirements can be determined. An arbitrary number of variables can be specified. An interactive program has been written and implemented on a number of interactive computer graphics systems. Using the graphic functions, search areas in which the optimum is expected to lie can be modified interactively, thus increasing the speed of convergence. Information about the equations can be given either interactively or in a file, therefore equations can be given either interactively or in a file, therefore relieving the user from the task of programming. The program has been applied to the design of gear pairs, steam condensors, and bearings.

Evaluating PHIGS for CAD and general graphics applications

The Programmer's Hierarchial Interactive Graphics System (PHIGS) is an International Standard for computer graphics and application modelling. Implementations of PHIGS for a variety of systems have been commercially available for a number of years, and it is rapidly increasing in popularity as an applications platform, both in industry and academia. The paper surveys the facilities provided by PHIGS, and draws on practical and published experience to present an evaluation of its suitability for CAD and general graphics applications.

Computer graphics standards for man modelling

The human being is arguably one of the most nonstandard and unpredictable components of all systems. Thus, in many application areas of computer-aided design, there is a need to model the physical aspects of humans alongside models of workplace and equipment. The paper briefly describes the Sammie systems, a long-established and succesful computer-aided design system that has fulfilled this requirement across a wide range of application areas. Recently, much development work has been aimed at incorporating a range of graphics and data-exchange standards into the Sammie software. These experiences are described, together with observations on their apparent limitations and advantages. In particular, the Programmer's Hierarchical Interactive Graphics System ( Phigs), its extension to Phigs-Plus, the Computer Graphics Metafile (CGM), the Initial Graphics Exchange Specification ( iges), and X-Windows with the Phigs extension ( Pex) are considered.

Optimization models and algorithms: an emerging technology for the motor carrier industry

Optimization models and algorithms for transportation are reviewed with the intent the providing lay management with at least a feeling of the range of technologies that are available and a sense of the strengths and weaknesses of each. The different types of applications of optimization to transportation that have evolved are described, and it is indicated how different methods are suited to different types of problems. Special attention is given to real-time optimization for truckload motor carriers. An interactive graphic simulation system, called MIDAS (micro dispatch and simulation), that was developed for demonstrating optimization methods is reported. It allows the user to compete against the optimization model in a real-time framework. >