Showing papers on "Graphics published in 1972"

Winged edge polyhedron representation.

Abstract: A winged edge polyhedron representation is stated and a set of primitives that preserve Euler''s F-E+V = 2 equation are explained. Present use of this representation in artificial intelligence for computer graphics and world modeling is illustrated and its intended future application to computer vision is described.

The Design Problem Solver, A System for Designing Equipment or Furniture Layouts,

Abstract: The Design Problem Solver (DPS) demonstrates that the computer can perform simple design tasks. In particular, it designs furniture and equipment layouts. This task was chosen because it is simple, well defined, and characteristic of many design tasks in architecture, engineering, urban planning, and natural resource management. These space planning tasks usually involve manipulating two-dimensional representations of objects, to create feasible or optimal solutions for problems involving topological and metric spatial constraints. DPS is a heuristic problem solver with a planning phase prefixed to it. It uses the planning process to give it a sense of direction, diagnostic procedures to locate difficulties, and remedial actions to recover from difficulties. It uses a convex polygon representation to accurately describe the objects and the layout. This representation allows topological and metric constraints to be tested and the design to be easily updated. While DPS is slow and limited in scope, the ideas behind it are general. It demonstrates the need for selectivity in controlling search, and demonstrates how to achieve it by using task specific information, planning, diagnostic procedures, remedial actions, and selective alternative generators. Ke[words: Artificial Intelligence, Computer-Aided Design, Design Synthesis, Diagnostic Search, Heuristics, Planning, Problem Solving, Representations, Search Strategies, Space Planning, Spatial Representations. 9/I O/7 2 Pfe fferkorn 1 1.0 Introduction To modify his environment, man has developed a wide variety of problemsolving activities referred to as "design". To investigate the possibility of using the computer as a designer, the Design Problem Solver (DPS) was written. It designs furniture or equipment layouts. This task requires placing objects in a room while satisfying a set of given constraints. The objects for an office might be desks, tables, file cabinets, and bookcases. The objects for a computer room might be the computer, its memory modules, and its I/0 equipment (magnetic tapes, card readers, printers, etc.). The constraints require that physical objects occupy independent regions of space, access areas be accessible, and path, view and distance constraints be satisfied. Figure I.1 gives a few examples of constraints which may be required. Figures 1.2 and 1.3 show sample problems and their solutions. The task is well specified: place the given objects in the room satisfying given constraints. This task was chosen because it is relatively simple, well defined, and characteristic of many design tasks in architecture, engineering, interior design, and urban planning, which require manipulating two-dimensional representations of objects to create feasible or optimal solutions to problems with a set of metric and topological spatial constraints. Eastman (1970 and 1970) refers to these design tasks as space planning problems. The objective of this empirical research was to identify key technic.al problems, to purpose tentative solutions, to provide guidance in building future design systems, and to suggest areas requiring further research. i.i Representation While human designers can solve design tasks by manipulating the physical objects used to complete the actual design, they usually solve an abstract version. In furniture or equipment layout problems, the designer (architect, engineer, or interior designer) usually avoids the effort and cost of moving the physical objects by using a simple model to represent the solution: pencil sketches, engineering drawings, small cutouts on a floor plan, or even miniature copies of the objects on a floor plan. The human designer must also select the constraints to use. Often the constraints a_e buried in the external environment, or in the designer's store 9/i0/72 P fefferkorn 2 of general knowledge. In either case, the designer must retrieve and apply them to the current problem. Poor solutions are frequently caused by a designer using the wrong constraints. Examining a designer's solution is also difficu'It because he seldom explicitly specifies the constraints he is using. Disagreement over the merits of a particular design often implicitly involves a disagreement over which constraints should be used to evaulate the design. If the computer is to solve design problems, it must have computer representations of the task which it can search and modify. DPS required both a spatial representation and a constraint representation. Its constraints were explicitly defined to avoid the problem of retrieving the correct constraints from context (the problem environment and definition). i.2 Problem-Solving If the computer is to solve a design problem, it must have a model of the design process, as well as, an abstract representation of the task. One possibility is to set design problems up as mathematical optimization problems. This technique requires forcing the original design problem into a form which can be solved by existing optimization techniques. This can be extremely difficult even for simple space planning tasks. An alternate approach is to use techniques developed from examining human problem-solving activities. The heuristic search method which is the basis of numerous existing artificial intelligence programs offers a viable alternative. In this model, problem solving is characterized as a process of search through a tree whose nodes are situations and whose branches are operations that transform one situation into another. A solution in this model is a path which leads from the initial situation to a goal situation. This model and its applications are described in several places including Newell (1969), Newell and Ernst (1965), Newell and Simon (1972), Nilsson (1971), and Slagle (1971). To implement a design problem using this model requires providing a set of operators and a representation of the initial problem which can be transformed into a final situation (solution) by applying the given operators. In DPS, the 9/10/72 Pfefferkorn 3 the initial situation is a list of empty rooms (usually one), a list of objects to enter the rooms, and a set of constraints to be satisfied. The steps between the initial situation and the final situation consist of partial layouts. The basic operation to get from one step to the next is to enter an object in the layout. The desired situation is a layout containing the required objects and satisfying the given constraints. In most problem solving situations, including design, the_tree of possible solutions (generated by applying the basic operators to the initial situation and all situations created from it) is immense. Because the size of this search space prohibits simple exhaustive techniques (in most cases) a search strategy must be developed which allows enough of the space to be searched to find an adequate solution. To minimize the number of branches created in finding a path to a desired solution node, the problem solver must be extremely selective in determining what branches to create (which node to expand and which operator to use in expanding it). When making these decisions the problem solver has two forms of information available: (I) information which is available when the problem is defined, and (2) information that becomes available as the search for a solution proceeds. In DPS, the initial information available includes the description of the objects, the rooms which the objects are to enter, and the constraints which must be satisfied. The information generated as the design progresses includes the current layout, the partial-design tree (the past history of DPS's search activity) and the statue of the different constratints (satisfactory, unsatisfactory, inactive or ready to be evaluated). 1.3 Organization of this Paper Numerous decisions must be made in building a design system. These decisions are discussed by describing DPS in sections 2 and 3 and by analyzing it in sections 4 and 5. Section 2 describes the task representation used by DPS: spatial representation (2.1), constraint representation (2.2), and design description (2.3). Section 3 describes the structure of DPS; search strategies (3._, main problem-solving functions (3.2 to 3.7), and the bookkeeping functions (3.8).

Raster-scanned display devices

Abstract: A synthetic graphics generating system, using a C.R.T. scanned in a T.V. type raster. The video signal for each linescan is calculated digitally in real time, either during the linescan flyback periods, or during execution of the preceding linescan. The described system is used to generate a number of vectors, the calculations for which are performed on a time-shared basis by common circuitry. To prevent a stepped appearance, progressive increase and decrease in brightness is used, preferably using three discrete brightness levels.

Microprogramming for computer graphics

Abstract: Interactive computer graphics (graphics) is the construction, storage, retrieval, manipulation, alteration and analysis of pictorial data, using an on-line display console with manual input (interaction) devices. Among such input devices are the alphanumeric and function keyboards for typing text and activating preprogrammed subroutines respectively, and the light pen and data tablet for identifying and entering graphic data by means of pointing and drawing.

Transit system planning: a man-computer interactive graphic approach

Abstract: A MAN-COMPUTER INTERACTIVE GRAPHIC SYSTEM FOR PLANNING NODE-ORIENTED (MULTIPLE-ORIGIN TO SINGLE-DESTINATION) TRANSIT SYSTEMS IS PRESENTED. THE SYSTEM IS IMPLEMENTED IN A REAL-TIME COMPUTER ENVIRONMENT WITH A CATHODERAY TUBE. THE USER DESIGNS A TRANSIT SYSTEM BY SPECIFYING ROUTES, PARK- AND-RIDE LOTS, VEHICLE CHARACTERISTICS, FREQUENCIES, FARES, AND PARKING FEES, AND THE COMPUTER IMMEDIATELY PREDICTS AND GRAPHICALLY DISPLAYS THE CONSEQUENCES OF THIS DESIGN. THE SYSTEM ENABLES A USER TO EXPLORE AND ASSESS A BROAD RANGE OF MULTIPLE-ATTRIBUTE ALTERNATIVES IN A SHORT PERIOD OF TIME, ASSISTS IN THE SEARCH FOR THE BEST DESIGN BY AUTOMATICALLY GENERATING EFFICIENT OPERATING CHARACTERISTICS FOR GIVEN ROUTE LAYOUTS, MAKES TRADE-OFFS BETWEEN COMPETING OBJECTIVES VISUALLY APPARENT, AND ALLOWS TESTING OF A SOLUTION'S SENSITIVITY TO PARAMETRIC VARIATIONS OF THE MODEL INPUTS. THE PAPER DESCRIBES THE MODAL SPLIT/NETWORK EQUILIBRIUM MODEL ON WHICH THE PREDICTION PROCESS IS BASED AND THEN ILLUSTRATES IN AN EXAMPLE THE MECHANICS AND CAPABILITIES OF THE MAN-COMPUTER INTERACTIVE APPROACH.

“An interactive, graphical system for the design of photomasks”

Abstract: A stand alone computer, a graphics input/output terminal and a comprehensive software system provide a rapid visual verification of digitized data from schematics to artwork.

The design of interactive graphics aids to mask layout

Abstract: Recently a number of interactive graphics aids to integrated circuit mask layout have been described. A review of the particular problems involved in implementing programs of this kind will be given with a description of hardware and software techniques available for their solution. Some features of these previously described programs will be compared and used to illustrate the range of solutions available. A program, IMP, will be described that uses some software techniques, not previously employed, to provide a capable and highly flexible mask layout facility on relatively inexpensive graphics terminals.

Increasing Capabilities in Interactive Computer Graphics Terminals

Abstract: The earliest interactive computer graphics terminals were closely coupled to their central computers and placed heavy loads upon them for resource allocation. Two marked trends in the evolution of terminals have been a reduction of central computer load and exploitation of the increasing performance/cost ratio for terminal equipment. The trends have led to graphics terminals that operate on a stand-alone basis. The history of these trends is traced and particularly illustrated by the cases of the fully interactive, refreshed CRT GRAPHIC 21 and the simply interactive, storage CRT GRAPHIC 101 terminals.

A report on the use of FORTRAN-coded EXPLOR for the teaching of computer graphics and computer art

Abstract: A FORTRAN-coded version of my EXPLOR language (for the production of images from explicit patterns, local operations and randomness) has been used to teach computer graphics and computer art to a collection of undergraduate students in art and computer science at the University of California at Santa Cruz. My conclusions are (1) that this particular language makes it possible for relatively inexperienced programmers readily to produce a wide variety of interesting designs, (2) that a rather significant scope and quality of computer graphics can be done with simply a line printer as the output device (other equipment became available during the program) and (3) that teaching of the important concepts of computing can be facilitated by the use of graphic output - i.e. graphics can be considered an effective approach to computing as well as vice versa.

Interactive graphics for schematic editing, a working tool

Abstract: LOGIGRAF, an interactive graphics program to lay out and edit schematic drawings, is now being used in a production environment at Bell Telephone Laboratories. The program runs on a GRAPHIC-211 graphics terminal (fig.1 ) which consists of a Digital Equipment Corporation PDP-15 computer with 8K of memory, secondary storage disk, card reader, 9 track tape, display processor, refreshed 21 inch CRT display, keyboard, light pen, function buttons, storage CRT, and hard copy unit. The cost of this hardware assuming a one shift operation and including maintenance is around d25/user hour.2 A virtual memory operating system is used to optimize the use of the 8K of core memory. The operating system and graphical programming support were developd as part of a general interactive graphics system for Bell Laboratories. LOGIGRAF is one of about a half dozen major application programs which all use the same system software. LOGIGRAF itself required almost three man years to develop and presently contains about fifty thousand words of Instructions. Programming was done in a higher level macro language designed for graphic application programming. Many technical obstacles had to be overcome in the development of the program. The most important of these had to do with providing a satisfactory user interface. In addition, a number o f new algorithms for dealing with the graphical data base permitted more complete graphical editing functions to be made available to the user.

Increasing capabilities in interactive computer graphics terminals

Abstract: The earliest interactive computer graphics terminals were closely coupled to their central computers and placed heavy loads upon them for resource allocation. Two marked trends in the evolution of terminals have been a reduction of central computer load and exploitation of the increasing performance/cost ratio for terminal equipment. The trends have led to graphics terminals that operate on a stand-alone basis. The history of these trends is traced and particularly illustrated by the cases of the fully interactive, refreshed CRT GRAPHIC 21 and the simply interactive, storage CRT GRAPHIC 101 terminals.

INSIGHT: an interactive graphic instructional aid for systems analysis

Abstract: INSIGHT (IN structional Systems Investigation GrapHic Tool) is an interactive graphics program which illustrates the basic concepts of systems analysis. The transfer functions, inputs, and parameters of a single loop control system are drawn on the graphic display. Numeric data entry, system modifications and control of the time domain and frequency domain analysis is performed using the graphics terminal's light pen. All communications are problem oriented and no previous computer experience is required.

Multiple-terminal hybrid graphics for control-system analysis

Abstract: Hybrid computation can be extremely efficient, not only in solving certain dynamics and control-system problems, but also in the graphical presentation and analysis of results. Analysis routines, simu lation, and animation can be interactively graphed in a time-shared mode using analog generated dis play with storage-type terminal screens. Many types of control problems amenable to graphical analysis and solution display may not require the large memory and sophistication of all-digital graphics. Hybrid-analog graphics provide an effi cient alternative, as demonstrated with two examples using root-locus and Nyquist diagram analyses. By employing the digital computer on an intermittent basis for calculation of root-locus and Nyquist data, efficient use is made of the analog in solving differential equations describing the system and in generating displays. Parallel effort between the two computers minimizes the total computational time required. Programming of analog logic allows a number of users of termi...

Automated map reading and analysis by computer

Abstract: A great deal of attention is presently being given to the design of computer programs to recognize and describe two-dimensional pictorial symbology. This symbology may arise from natural sources such as scenery or from more conventionalized sources such as text or mathematical notation. The standardized graphics used in specification of topographic maps also form a conventionalized, two-dimensional class of symbology.

User Desires and Graphics Capability in the Academic Environment

Abstract: This paper is an attempt to determine the average geography academic's needs in relation to his research requirements and computing knowledge in automated map production. Usually he will not be attempting to produce a final map, but probably only one to enable him to analyse his data with more accuracy. An outline is given of what the user can expect from a plotting system, and also what he will have to know to benefit from the results produced. The problem of contouring is taken as a demonstration of the difficulties involved. Examples are given to show that no computer contour map can be considered objective, and that the results produced are determined by the contouring method employed combined with the skill of the user.

GRAPHOS: A macro directed system for two-dimensional syntax translation

Abstract: A system is presented which translates two-dimensional syntax into a one-dimensional form. The concept of a macro is extended so as to be applicable to these two-dimensional forms. The translation process is controlled by a set of user-defined graphical-macros or “graphos”. These graphos are interactively defined on a graphics terminal and placed in a set of master tables. Two-dimensional expressions are then constructed on the graphics terminal. The system translates these expressions by interpreting the user's grapho definitions. These definitions specify the final form of the output which is one-dimensional text suitable as source input to a higher-level language processor. The organization of the GRAPHOS system is discussed, and examples of grapho definitions and their expansions are presented.

Some experiences in implementing Network Graphics Protocol Level 0

Abstract: We are in the process of implementing NGP-0 at several hosts. For the time being, we are forced to consider the remote host as the "last intelligent machine". We are attempting to translate NGP-0 to a machine dependent code for the Computek display. The remote hosts are CCN, UCSD, and soon RANDCSG. More comments about that work will be made in subsequent RFC's. The concern of this RFC is twofold: 1. Clarify the coordinate number system. 2. Puzzle over how to do TEXTR string without either: a. Reading current position and saving it while the text string is being output, or b. Monitoring the beam position for each NGP command and saving this information somewhere. An appendix to this RFC will outline the conversion from the NGP coordinate system to the floating point arithmetic on the PDP-1O. The Coordinate Data The document for NGP-0 (RFC 292) does not say specifically that the format of coordinate data is the same whether the command is in absolute or relative mode. The only thing stated is that they are in two's complement notation with the leftmost bit being the sign bit. It is possible to use two different 2's complement schemes:

META 4A Principles of Operation

Abstract: : The publication is one of the machine reference manuals for the Brown University Graphics System (BUGS). The META 4A is the general-purpose processor component of BUGS. Readers are assumed to have a knowledge of the principles of operation of the IBM System/360. (Author)

Graphics in APL

Abstract: This document describes an experimental graphic facility within APL. The terminals are assumed to be inexpensive timeshared graphic terminals equipped with an APL character set. We first describe functions in a graphic workspace, and then APL primitives for graphing.

PICASSO a general graphics modeling program

Abstract: A new two-dimensional graphics modeling program which has been fully implemented is introduced. Features include a generalized extendable graphics editor, an open-ended library of elements, a translator -macro processor for interface with a wide range of analysis routines, and on-line operating system control.

The Assistant Mathematician: An interactive graphic programming language

Abstract: This paper describes an experimental interactive graphics system called The Assistant Mathematician (TAM). TAM is a prototype computational aid for non-programmers, particularly engineers or scientists, that uses ordinary two-dimensional mathematical notation as its language. The system includes an arithmetic interpreter, incorporating an extensive set of arithmetic operators on constants, variables, and arrays, that accepts hand-printed graphic (two-dimensional) input from a data tablet and supplies two-dimensional output via a projection display system. TAM is one of a class of potential interactive graphics systems useing natural language to improve man-machine communication.

Computer graphics in medicine: Six theses

Abstract: The objective of this paper is not to present a catalog of current or potential applications of computer graphics in medicine, but rather to raise some basic key issues for consideration. The six theses which I am exploring are:1. Iconic Communication must be the ultimate objective of computer graphics;2. Possibilities for dynamism and interaction provide exciting dimensions for graphic presentation;3. Use of the Optimality Principle can assist in promoting rapid progress;4. The Building Block Principle is useful for system development and application as well as initially getting started;5. Adherence to simple design principles can enhance graphic effectiveness; and6. Cost-Benefit is a key factor in graphics system evaluation and utility.Each of these theses will be considered in turn in an effort to lay the groundwork for discussing, analyzing and evaluating computer graphics in medicine. It must, of course, be noted that all principles discussed here are pertinent to computer graphics in general and not just related to medicine. In medicine however, the problems are often more difficult to deal with and the consequences greater. Thus interdisciplinary communication is critical if the problems are to be solved.

Symbolic computer graphics and biological models

Abstract: In the first part of my talk I will describe the operation of a symbolic graphics computer system; next, I will show how some models can be implemented by using this system, and finally I want to discuss techniques for establishing the validity of models.

An on-line two-dimensional computation system

Abstract: The role of graphics in interactive man-computer systems is to extend the capability of the computer for communication in a visual mode so that men can communicate with the computer directly in the figurative notations and graphics conventions that they have developed for communication among themselves. A large number of computer-graphics systems have been developed, most of them directed toward drawing lines, curves, or shapes, as in schematic drawing, solid and half-tone drawing, and computer animation. Considerable work has also been done in computer output of drawings and graphs.

Computer aided graphics in architecture and planning

Abstract: Computer-aided graphics is illustrated by the use of ARK 2 system in two and three dimensional graphics manipulation. The ease of using this system is emphasized. ARK 2 is a user-oriented computer-aided design system for architects and planners who have little knowledge of computers.

Interactive digital processing of optical data

Abstract: Interactive digital processing of optical data is shown to be useful in investigations of pattern recognition techniques. A system including a flying spot scanner and graphics terminal for the optical to digital conversion and subsequent display of two-dimensional images is described. Application of such a system is demonstrated by interactive contour tracing and character recognition by template matching. Algorithms necessary for the applications are developed and tested.