Graphic Devices Research Articles

Color vision defects in ocular hypertension and glaucoma. Quantification with a computer-driven color television system.

In order to detect early defects of color vision caused by increased intraocular pressure, a computer graphics device and color monitor system were used to measure color contrast sensitivity. The system determines the threshold chrominance of a colored grating in which there is no change in luminance. The study included 13 control subjects aged 10 to 57 years and 19 patients with ocular hypertension or glaucoma aged 20 to 58 years. In the 13 eyes with visual field loss, color contrast sensitivity was profoundly reduced when the grating colors fell on a tritan color confusion line. In the eyes without visual field loss, tritan color contrast sensitivity was reduced to an average level considerably below the extreme limits of the control group. These results were compared with those of other color vision tests and diagnostic criteria for glaucoma. The findings suggest that among the tests used, color contrast sensitivity testing was able to discriminate most effectively between patients who had retinal damage and the normal population.

Solid perception mechanism by a shading pattern: Spatial frequency components in a corrugated wave pattern

Illumination allows solid object perception to be obtained and depicted by a shading pattern produced by lighting. The shading cue, as one of solid perception cues (Gibson 1979), was investigated in regard to a white corrugated wave shape, using computer graphic device: Tospix-2. The reason the corrugated wave was chosen, is that an alternately bright and dark pattern, produced by shading, can be conveniently analyzed into contained spatial frequencies. This paper reports spatial frequency properties contained in the shading pattern. The shading patterns, input into the computer graphic device, are analyzed by Fourier Transformation by the same device. After the filtration by various spatial frequency low and high pass filters, Inverse Fourier Transformation is carried out for the residual components. The result of the analysis indicates that the third through higher harmonics components are important in regard to presenting a solid reality feeling in solid perception. Sakata (1983) also reported that an edged pattern, superimposed onto a lower sinusoidal pattern, was important in solid perception. The third through higher harmonics components express the changing position of luminance on the pattern, and a slanted plane relating to the light direction. Detection of a solid shape, constructed with flat planes, is assumed to be on the bottom of the perfect curved solid perception mechanism. Apparent evidence for this assumption, in difficult visual conditions, is that a flat paneled solid is seen before the curved solid. This mechanism is explained by two spatial frequency neural network systems, assumed as having correspondence with higher spatial frequency detection and lower spatial frequency detection.

A system for the analysis and comparison of oceanographic data from satellite-borne and in-situ sensors

ODESSA is an Oceanographic Database and Environmental Satellite System Application developed for ARE (Portland) by Logica Space and Defence Systems Limited, under Ministry of Defence contract. It is possible to access online or historic satellite images, which may be processed and displayed in a variety of formats. The oceanographic database contains data as a function of depth that have been derived from a wide range of instruments, geographic areas and times. This database may be accessed and the data processed and displayed in a number of ways, some of which can be directly overlaid and compared with the processed satellite images. The system was designed to be flexible, with an emphasis on the man-machine interface, making extensive use of menus and graphic input devices. The flexibility allows for easy expansion to include further processing and display facilities. Examples of output displays are presented to show the application of the ODESSA system in oceanographic modelling studies and in relating sea-surface temperatures to the three-dimensional water-column structure.

Model building of disulfide bonds in proteins with known three-dimensional structure.

As an aid in the selection of sites in a protein where a disulfide bond might be engineered, a computer program has been developed. The algorithm starts with the generation of C beta positions from the N, C alpha and C atom coordinates available from a three-dimensional model. A first set of residue pairs that might form a disulfide bond is selected on the basis of C beta-C beta distances between residues. Then, for each residue in this set, S gamma positions are generated, which satisfy the requirement that, with ideal values for the C alpha-C beta and C beta-S gamma bond lengths and for the bond angle at C beta, the distance between S gamma of residue 1 and C beta of residue 2 in a pair (determined by the bond angle at S gamma 2) is at, or very close to its ideal value. Usually two acceptable S gamma positions are found for each half cystine, resulting in up to four different conformations for the disulfide bond. Finally, these conformations are subjected to an energy minimization procedure to remove large deviations from ideal geometry and their final energies are calculated. User input determines which final conformations are energetically acceptable. These conformations are written to a file to allow further analysis and e.g. inspection on a computer graphics device.

The case for assembly language programming

A successful educational course on assembly language programming at the University of Illinois is described with particular emphasis on its pedagogical innovations, including the treatment of multitasking and the provision of library versions of subroutines. The course reinforces fundamental concepts of both data and control structures by illustrating their machine-level implementations. The machine problems provide experience with the design of large programs and with real-time data acquisition and control graphic devices. >

Solid Perception Effected by Spatial Frequency Components in a Shaded Pattern:

The purpose of illumination is to allow solid perception to be obtained and depicted by a shaded pattern produced by lighting. The shading cue, as one of solid perception cues, was investigated, using a computer graphic device: Tospix-2. The corrugated wave was chosen for a test pattern, because an alternately bright and dark pattern, produced by shading, could be conveniently analyzed into contained spatial frequencies. This paper reports spatial frequency properties contained in the shading pattern. The shading patterns, which were actually shaded or were produced by computer simulation, were analyzed by Fourier Transformation by the same device. The result of the analysis indicates that the third through higher harmonics components are important. For observation of a solid shape, flat planes are assumed to be on the bottom of the completely curved solid perception. As apparent evidence for this assumption, under difficult visual conditions, a flat paneled figure was seen, in spite of the curved solid.

Graphics in Reservoir Simulation

AbstractReservoir Simulation is used to manage underground oil reservoirs, and the potential cost savings associated with increased oil recovery are enormous. Because of the mathematical complexity of simulation it is necessary to use graphics to view the results. Graphics programs in this environment must be easy to use, and capable of producing images on a variety of machines and graphical devices. The paper looks at some of the problems involved.

Program Structure Charts for Applicative Languages

A framework for a system of charts compatible with the use of applicative programming languages is proposed and illustrated. The charts are similar in spirit to the structured flowcharts that have sometimes been used with algorithmic languages. They are based on a method of representing the structure of nested expressions of arbitrary complexity. This method is adaptable to the incorporation of graphical devices for the depiction of local identifier bindings, conditional expressions, recursive function definitions, and the various functional combining forms employed in the FP-style of applicative programming.

Interactive statistical analysis of survival data

This paper describes a SAS macro which facilitates the interactive analysis of right-censored survival data. Such data commonly occur in medical studies. The program produces Kaplan-Meier survival curves on a wide variety of graphics devices. The program also performs log-rank and generalized Wilcoxon significance tests among all plotted curves and for each pairwise contrast if desired. Because the program is intelligent and does not prompt the user for information that it can independently obtain, it is quite easy to use.

An interactive FORTRAN 77 program using GKS graphics for 2.5 D modeling of gravity and magnetic data

An interactive 2.5 D gravity and magnetics modeling program has been written for an ICL PERQ 2 workstation using FORTRAN 77 and GKS graphics. All of the available hardware and software input devices are utilized through GKS to produce an easy-to-use menu-driven program. A large number of functions are controlled by the software in order than the user can concentrate on the model. A range of options also are provided for manipulating the observed anomaly. The use of FORTRAN 77 and GKS should make the program easily portable to other computer systems and graphics devices. The modular form of the program should facilitate readily further development including optimization and real time modeling, given a more powerful computer with high-speed graphics.

The evolution of a graduated symbol software package in a changing graphics environment

Abstract The paper describes the developmental history of a software package for computer-assisted drafting of graduated symbol maps. Given the machinery prevalent 10 years ago, the first version was implemented on a mini-computer with vector-oriented devices, such as mechanical plotters and storage tube terminals. The programs provide functions for plotting graduated symbols of various forms, legends and Line drawing. To improve map legibility the hidden areas in cases of overlapping symbols are removed. The visual separation of the symbols is enhanced by a halo effect, a small gap between the symbols, or the symbols and map background. New hardware required the reprogramming of the package to exploit the extended capabilities of new computers and graphic devices, including colour and hardware area fill. To increase flexibility, portability and maintainability, the graphic standard GKS (Graphical Kernel System) has been used as a device-independent software interface for the third generation of the package.

Structured Development of a Petrophysics Laboratory Computer System to Aid in Formation Evaluation and Geologic Interpretation: ABSTRACT

Problem solving, data collection, and analysis in geology require diverse tools and methods. Computers must be convenient and versatile to be useful as laboratory apparatus and as tools for use in formation evaluation and geologic interpretation. Networking and distributed intelligence provide a laboratory with flexibility and power for cost-effective real-time data collection, management, and analysis. Networking facilities toolbox-style programming; improves data compilation, management, and comparison; and increases peripheral effectiveness. Distributed intelligence enhances local instrumentation, uninterrupted real-time data collector, and data analysis. The system presented includes facilities for instrumentation, data collection and management, and interpretation, analysis, and presentation for such systems as mercury injection, rock electrical properties, gas slippage, Klinkenberg correction, gamma-ray logging, cation exchange capacity, thermal neutron capture cross section, and permeability/porosity measurements. The individual systems share central text and graphic hard-copy devices and high-speed mass storage and backup facilities. Modifying the central system updates many of the remote system facilities such as user interfaces and graphic facilities. Individual system configurations include instrumentation, high-resolution color graphics, analog to digital conversion, and variation in computing power.

Teaching aerodynamics using a microcomputer

An interactive and wholly automatized computer code has been developed on a microcomputer for the aerodynamic analysis of airfoils in incompressible now fields. It is intended to serve as a useful support in teaching aerodynamics. The code contains a number of modules (or blocks) for: (1) drawing the shape with the help of an interactive graphic device interfaced with the microcomputer; (2) computing the aerodynamic inviscid and viscous flow field and the aerodynamic coefficients; (3) modifying and/or correcting the body shape and then computing the new aerodynamic coefficients. In this way the student can evaluate, operating directly and interactively, the influence of the changes in shape on the aerodynamics of the airfoil under study.

Algorithm for ribbon models of proteins

A method is presented to draw smooth, 3D ribbon models of proteins. The procedure calculates closely-spaced guide coordinates based on the peptide plane and passes regular, nearly parallel B-spline curves through them. This becomes a simple process with a graphics device having built-in B-spline generating capabilities such as the Evans and Sutherland PS300. Examination of ribbons such as these provides a useful tool for the crystallographer. Any irregularity in the ribbon is a strong visual cue, suggestive of potential problem areas during the refinement process.

Nucleic acid secondary structure prediction and display

A set of programs has been developed for the prediction and display of nucleic acid secondary structures. Information from experimental data can be used to restrict or enforce secondary structural elements. The predictions can be displayed either on normal line printers or on graphic devices like plotters or graphic terminals.

An efficient algorithm for the dot generation of arbitrary ellipses

AbstractThis paper presents an algorithm which provides a high‐speed dot representation of an ellipse on the raster‐scan graphic display device. In the usual graphic display, straight‐lines and circles are used as the graphic primitives. In the three‐dimensional graphics, a projection on the two‐dimensional plane is often employed where a circle is in general projected as an ellipse. When a curve with rapidly varying curvature is to be represented, the approximation can be effected by a fewer number of components if ellipses are used instead of circles. From such viewpoints, an efficient generation algorithm for the ellipse is required. The ellipse considered in this paper need not have the long or short axis parallel to the coordinate axis. The lengths of the long and the short axis are arbitrary, and the correct dot generation is observed for an extremely oblong ellipse. The location of each dot is determined so that the deviation from the ellipse is small. Sometimes the past method does not work due to the fact that the ellipse is a two‐valued function. By contrast, this paper contains a simple scheme to convert the ellipse into a single‐valued function. To improve the speed of the algorithm, only addition‐subtraction and conditional test are used in the internal loop determining the dot location.

Metafiles and computer graphics

This paper presents an overview of the development and need for a standard way of storing and recalling graphical picture data. An international standard for a computer graphics file has been developed. This file, called a “metafile,” provides functional elements and formats for device-independent representation of pictures intended for subsequent display on graphical output devices. The use and benefits of standard metafiles for defining and transporting pictures in the computing environment is explained.

A workstation model for an interactive graphics system

By introducing the concept of an abstract graphics device called the workstation, an existing graphics system is generalized to support multiple devices in applications software.

Interactive graphics for geometry generation - A program with a contemporary design

The aerodynamic design process is now strongly influenced by the application of advanced computational tools due mainly to recent advances in computer capabilities. Today's aerodynamic analysis codes require large amounts of geometric data to define the surfaces in sufficient detail for proper analysis. A program has been developed to aid the engineer in generating geometric models for computational aerodynamics codes. The program, Interactive Graphics for Geometry Generation (I3G), is not dramatically different on the outside from other interactive graphics programs of this type. It is, however, different on the inside, i.e., in how it performs its functions. I3G is capable of accepting input from a variety of geometry sources and can support the generation of geometric models for many different computational codes. User-friendly operation encourages program use. Graphics devices ranging from sophisticated systems to low-cost display-only terminals can be easily supported by I3G. The program's modular structure allows new modeling capabilities to be readily incorporated. A system for indexing and retrieving existing geometric models is available to the user. In summary, flexibility is the key word behind I3G's basic design and structure. This feature allows modifications and enhancements to be readily made as needs change or arise. Succinctly, it is a program designed to last.

Use of Graphic Devices in a Competitive Situation: A Case Study of 10 Cities

Graphic devices used by newspapers in a competitive situation were analyzed. The study included separately owned, broadsheet newspapers of at least 100,000 circulation in 10 U.S. cities. Findings were: 1) Pairs of competing newspapers in close circulation battles tend to be more similar in their use of graphic devices than those whose circulation is not close; 2) Newspaper trailers (less circulation) tend to use more modern graphic devices than newspaper leaders; 3) Morning papers use more traditional graphic devices than afternoon papers, which use more traditional devices than all-day papers; and 4) The larger circulation papers tended to be the most traditional while the smaller circulation papers tended to be the most modern.