bluuebunny/crossref_metadata_2025_split huggingface dataset:
Algorithms for Handling the Fill Area Primitive of GKS
Authors: Shinde Yogesh N. , Mudur S.P. 
Published: October 2007

AbstractThe fill area primitive of GKS (Graphical Kernel System)1 is one of the more powerful features which differentiates it from earlier device independent graphics software and systems. Its specification is extremely general in the form of a closed boundary, possibly self‐intersecting, and whose interior can be filled in a variety of styles. However a complete implementation of this primitive is very complex. It is difficult to find a single graphics workstation incorporating this primitive in hardware or firmware. Most GKS implementations will have to include software for simulating the appearance of this primitive on the commonly available displays and hard‐copy graphics devices. Correct and efficient algorithms are necessary for developing this software. Because of the generality many of the existing algorithms are not directly applicable. In this paper we describe:1. a new algorithm for clipping a fill area polygon, using what we have named as the Bridge Technique.2. implementation of a plane sweep algorithm, by Nievergelt and Preparata,2 for solid filling and hatching, particularly applicable to vector devices.3. extension of the plane sweep algorithm for filling with any given pattern on raster as well as vector devices.The algorithms have been designed to work for all special cases as well. In fact they have been implemented having in mind the fill area set primitive of GKS‐3D extension.3 All these algorithms have been very successfully implemented in a commercially available GKS implementation, namely indoGKS.
A Token Based Graphics System
Authors: Reynolds Graham J. 
Published: October 2007

AbstractThis paper presents the design of a novel process oriented graphics systems architecture suitable for emulating many general purpose computer graphics systems. The systems architecture has been designed loosely on the actor model of computation, and consists of a number of functionally distinct modules or processes, which communicate solely by token (message) passing. The design addresses a specific requirement for configurability and adaptability of and between modules identified within interactive computer graphics systems.
An Integrated Graphics Programming Environment
Authors: Morrison R. , Florianis A.L. , Dearle A. , Atkinson M.P. 
Published: October 2007

AbstractThe facilities of the PS‐algol programming language are described in this paper to show how they may be used to provide an integrated graphics programming environment. The persistent store mechanism and the secure transaction facilities of the language provide the basic environment in which an integrated system may be implemented. This is augmented by data types and operations to support line drawings and raster graphics. The combination of these mechanisms may be used to provide the integrated graphics programming environment.
Fast Operations on Raster Images with SIMD Machine Architectures
Authors: Arabnia H. R. , Oliver M. A. 
Published: October 2007

AbstractAlgorithms for fast operations on a raster image data structure are described. The data structure and algorithms have been designed to exploit SIMD parallel architectures. Images of lines, discs and circles can be created efficiently. Images can be translated, scaled, and combined. The data structure is closely related to runlength encodement. The algorithms have been implemented on an ICL DAP on which the operations can be done in real time (on non‐trivial images).
A Monte Carlo Approach for ɛ Placement in Fractal‐Dimension Calculations for Waveform Graphs
Authors: Pickover C.A. 
Published: October 2007

AbstractMany diverse and complicated objects of nature and math possess the quality of self‐similarity, and algorithms which produce self‐similar shapes provide a way for computer graphics to represent natural structures. For a variety of studies in signal processing and shape‐characterization, it is useful to compare the structures of many different “objects”. Unfortunately, large amounts of computer time are needed as prerequisite for rigorous self‐similarity characterization and comparison. The present paper describes a fast computer technique for the characterization of self‐similar shapes and signals based upon Monte Carlo methods. The algorithm is specifically designed for digitized input (e.g. pictures, acoustic waveforms, analytic functions) where the self‐similarity is not obvious from visual inspection of just a few sample magnifications. A speech waveform graph is used as an example, and additional graphics are included as a visual aid for conceptualizing the Monte Carlo process when applied to speech waveforms.
Artificial Intelligence in Three‐Dimensional Computer Animation
Authors: Thalmann D. , Magnenat‐Thalmann N. 
Published: October 2007

AbstractRecent developments in hardware and software have led to the production of complex computer‐generated images and films. Sophisticated algorithms like ray‐tracing, fractals or particle systems allow the generation of very realistic natural scenes. However, the design of images and films is still a painful task for designers, because of the inadequacy of person‐machine interfaces. A large number of parameters is necessary to build objects (curves, surfaces) to define their properties (orientation, size, colour, transparency, texture, reflectance), to specify the viewing angle, to control the lights and shadows, to define and synchronize motions.The technology of artificial intelligence and more specially knowledge engineering makes possible the development of intelligent human‐machine interfaces for image synthesis and animation. Designers may communicate with design and animation systems using natural language. Basic geometric rules may be given to the computer, making it an expert in 3D geometric modeling. Languages based on the concept of frame simplify the intelligent description of complex objects. Expert systems allow the designer to specify the conditions of an image using goal‐directed specifications for cameras and lights. Scripts and actors are particularly appropriate for the description of motions; the impact of these concepts on 3D computer animation is considerable. Finally, the complex problem of animation of articulated bodies may be solved using knowledge‐based animation. Examples are presented using our new language EXPERTMIRA. This language is based on MIRA and PROLOG and incorporates concepts of artificial intelligence, image synthesis and animation.
Arbitrary Rotation of Raster Images with SIMD Machine Architectures
Authors: Arabnia H.R. , Oliver M.A. 
Published: October 2007

AbstractAn algorithm for the rotation of a raster image by an arbitrary angle is described. The image data structure is closely related to runlength code. The algorithm has been designed to exploit SIMD parallel architectures. It has been implemented on an ICL DAP on which non trivial images can be rotated in times very close to real time.
Using Abstract Data Types To Define Large‐scale World Models For Image Generation Systems
Authors: Marsh S.C. , Grimsdale R.L. 
Published: October 2007

AbstractThe creation of databases for real‐time image generation systems is expensive and time consuming. This is mostly due to the method of defining the world models which can currently represent an area of up to 500,000 sq Km. This paper suggests that abstract data types can decline the necessary elements of world models. A programming language containing these data types can then be used to specify the construction of world models, and greatly reduce the time taken to create the databases.
A User‐Interface Toolkit in Object‐Oriented PostScript Owen M. Densmore
Authors: Densmore Owen M. , Rosenthal David S. H. 
Published: October 2007

AbstractOnly the diehards want to develop applications using basic window system facilities. The preferred approach is a higher‐level “toolkit” of user interface components, such as menus and scroll bars. Experience with current toolkits shows the need for an object‐oriented interface to these components.NeWS, the Network/extensible Window System, allows user interface components to be programmed in PostScript. Fortunately, object‐oriented interfaces are natural in PostScript, and they have been used to create a toolkit with some novel properties. Among these are the use of concurrent processing and run‐time inheritance of component methods.“Postscript is the future of words on paper.”Arthur C. Clarke
Techniques for Animation on Microcomputers
Authors: Neelamkavil F. , Beare L. 
Published: October 2007

AbstractAnimation is a powerful visualization aid and it has applications not only in the traditional areas of cartoons and fiction movies but also in the study of a wide variety of natural and simulated phenomena. Currently, there is growing interest in the study of animated algorithms and data structures particularly due to the availability of cheaper and more powerful microcomputers. Computer animation may use complex graphics systems and therefore the quality and speed of the graphics display are extremely important. Various techniques for animation on microcomputers are examined and it is shown that Scrolling techniques can be successfully applied for realistic animation in many application areas. Macintosh implementations of “animated algorithms” are used to illustrate the effectiveness of the method.
A Texture Mapping Approach to 3‐D Facial Image Synthesis
Authors: Yau John F.S. , Duffy Neil D. 
Published: October 2007

AbstractA method of synthesising and animating a realistic image of a person's face by means of computer graphics is described. The key feature contributing to realism in image synthesis lies in the use of texture mapping in the rendering of surface detail on the face. Full facial animation is made possible by manipulating a 3‐D model of the face in conjunction with a relatively small data set of pre‐stored sub‐images.
Some Remarks on the Modelling Gip Problem
Authors: Herman I. , Reviczky J. 
Published: October 2007

AbstractThe modelling clip as proposed for example in PHIGS is mathematically analyzed and a method to perform it is proposed. The method has the particular edvantage of avoiding all possible singularities appearing in the course of a projective transformation. Additionally, further optimizations in the implementation of the whole output pipeline are proposed.
A Note on Random Thresholding for Colour Synthesis
Authors: Lastra G.L. , Rüdinger E.N. 
Published: October 2007

AbstractA simple algorithm that improves colour shaded images is presented. The algorithm does not trade spatial resolution for intensity resolution. The basic technique, based on random thresholding modulated by a pseudo‐random number generator of uniform distribution, is introduced to render halftone images on bi‐level displays. A generalization of the technique is done for displays with multiple bi‐per‐colour components. An obvious advantage of the algorithm presented over other reported methods is its simplicity. Pictures are included to show results of the algorithm.
On Implementing Parallel GKS
Authors: Arnold D.B. , Hinds M.R. 
Published: October 2007

AbstractThis report investigates the problems involved in implementing the GKS 2D graphics standard in Occam. Whilst some of the detail is language specific, similar problems arise with implementations in any parallel system and the paper therefore has wider relevance. The main problems were found to be the lack of data types in Occam, parallel calls to the GKS implementation (which assumes a sequential command stream) and implementing a truly parallel GKS kernel. None of these problems appears to be insuperable, particularly if a preprocessor is used to overcome the potential communication and network conflicts which are possible in a parallel graphic system.
SIAS, Strokes Interpreted Animated Sequences
Authors: van Berkel Pierre 
Published: October 2007

AbstractThe goals of the bulk of commercial computer systems for graphics and animated film/video are different from the kind of systems involving the production of art. The former systems are developed for industrial application. Accurate technical communication and precise representation of measures are the main goals of the drawings and die coloured plates intended for industrial application.In the arts, however, the main goal of a drawing, a painting, or an animated film/video is beauty. The visual artist searches for an equilibrium between proportions of different shapes and an equilibrium between different colours. A system able to help in this search must therefore have its roots in art, i.e. the so‐called modern art. Starting from my experience in painting, in animated film by pencil drawing, and in computer animation, I concluded that a scene could be represented very effectively and accurately by the technique of painting and drawing.The system presented for automatic painting of scenes within a 3D space that are changing in time, is based on the tradition of drawing and painting. The system must be applicable within the visual arts and video production. An experimental computer animation system SIAS (Strokes Interpreted Animated Sequences) has been developed which produces coloured shapes that are similar to the strokes put on a canvas by a painter.
A Framework for Functional Specification and Transformation of Hidden Surface Elimination Algorithms
Authors: Lakshminarasimhan A.L. , Srivas Mandayam 
Published: October 2007

AbstractThis paper deals with the theory of hidden surface elimination algorithms in Computer Graphics. A set of functions and abstract data types are defined to help concisely specify a class of hidden surface elimination algorithms in a purely functional language. A formal study of these algorithms is presented here along with theorems of equivalence between some of the specifications. It is shown here that such proofs of equivalence will help in the construction of existing as well as new algorithms. We bring in the importance of such a study to exploit alternative parallel architectures for implementation of these algorithms. The other benefits of formal specification and analysis are due to its use as a teaching aid and effective method for rapid prototyping of these algorithms.
Image Representations Using Miranda Laws
Authors: Parsons Michael S. 
Published: October 2007

AbstractThe applicative language Miranda is used to define various image representations. One particular feature of this language, an algebraic data type with laws, is shown to be very powerful in giving and automatically maintaining properties of these image structures. This enables simple definitions of graphical ideas such as the following: quadtrees which are always fully condensed, self‐dividing line lists which produce fractal images, and primitives restricted to certain areas of the screen or to certain orientations.
Motion Control in Animation, Simulation and Visualization*
Authors: Hegror Gerard , Palamidese Patrizia , Thalmann Daniel 
Published: October 2007

AbstractThis paper discusses the role and the evolution of animation, simulation and scientific visualization and their relationships. Two trends are described: (1) the physical laws are well‐known and their use improves the animation; (2) the physical laws are not really well‐known and the animation techniques contribute to understanding them. We distinguish descriptive models used to reproduce an effect without knowledge about its cause and generative models describing the cause which produces the effects. Cooperation between descriptive and generative models is also discussed as well as man‐machine interface constraints. Finally, the evolution of animation towards automatic motion control, goal‐oriented motion, task modeling and behavioural animation is emphasized.
Graphics Object Management in The X Window System
Authors: Davison Allan , Slater Mel , Smith Mark 
Published: October 2007

AbstractThis paper describes a library for the creation and manipulation of geometrically defined graphical objects in The X Window System Objects are arranged in a 2.5D space, and can be transformed, made invisible or visible, or have their priority changed. Transformation of objects occurs immediately and with full damage repair, thus providing an essential requirement for the support of interactive graphics. The paper reports on an experimental implementation of the library and also discusses the implications of graphical objects in the X environment.
Project DIGIS: Building Interactive Applications by Direct Manipulation
Authors: Bos Jan van den , Laffra Chris 
Published: October 2007

AbstractDIGIS is a design and implementation system for developers of general purpose interactive applications (IA). It is itself an interactive system that accomplishes its task by Direct Manipulation techniques, in principle without using a programming language. DIGIS is a generator in the form of a window‐based workbench. It has two input sources. One is a toolkit of predetined interaction tools consisting of prototypes and instances. The other is the set of predetined application procedures thai make up the application part of the IA. The application procedures do not handle user input but may handle textual or graphical screen output. The task of the developer is to build the user interface by selecting the appropriate interaction tools. tailor them to the interface, and tie them to application procedures. This includes the visual representations of interaction tools, their prompts, echoes and feedback. In the process he maps user input to parameter lists for the application procedures, and return parameters to interface output. DIGIS will also support the detinition of composite input (interaction patterns such as sequences). Unix and X are the initiat operating environment, adaption of the input sources to PCTE. OSF/Motif, and Open Look is feasible and anticipated.The design of DIGIS is based on a hierarchical interaction model that is the second focus of this paper. The implementation will be done using PROCOL, a locally developed concurrent object‐oriented language. which offers protocols that support composite input. The language is a superset of C, and therefore fully compatible with existing C libraries.ACM Categories and Subject Descriptors:D.2.2 [Software Engineering]: Tools and Techniques ‐user interfaces, programmer workbench;D.3.3 [Programming Language]: Language Constructs ‐input/output, programming structures;H.1.2 [Models and Principles]: User/Machine Systems ‐human factors;1.3.6 [Computer Graphics]: Methodology and Techniques ‐ interaction techniques, ergonomics, languages:
Factoring a Homogeneous Transformation for a more Efficient Graphics Pipeline
Authors: Abi‐Ezzi Salim S. , Wozny Michael J. 
Published: October 2007

AbstractWe identify an intermediate coordinate system situated between world coordinates and display coordinates, which exhibits unique features for lighting calculations and for clipping in homogeneous coordinates. Our key contribution is an algorithm for extracting such a coordinate system from a homogeneous viewing transformation that relates WC to DC. The algorithm is based on factoring the transformation into a product of a Euclidean factor and a sparse (computationally cheap) but non‐Euclidean factor.A particularly strong application of the proposed technique is the graphical processing of curved surface primitives, such as what is needed in the PHIGS PLUS viewing pipeline. Furthermore, in PHIGS PLUS the graphical data is retained by the graphics system, therefore, it is possible to perform the factoring of the viewing transformation at creation time, and to take advantage of this factored form at traversal time.
3D Display: Synthetic Image Generation and Visual Effect Simulation
Authors: Theoharis T. A. , Travis A. R. L. , Wiseman N. E. 
Published: October 2007

AbstractTwo viewing models are presented for a promising type of three dimensional display: they are based on parallel oblique and perspective oblique projections respectively. A detailed simulation compares the quality of the images that will be produced by each projection type and points out potential problems. The time necessary to alter the image of the three dimensional display will be comparable to that of conventional displays by the use of a simple parallel processing scheme.
A Direct Manipulation Technique for Specifying 3D Object Transformations with a 2D Input Device
Authors: Van Emmerik Maarten J.G.M. 
Published: October 2007

AbstractA mechanism is presented for direct manipulation of 3D objects with a conventional 2D input device, such as a mouse. The user can define and modify a model by graphical interaction on a 3D perspective or parallel projection. A gestural interface technique enables the specification of 3D transformations (translation, rotation and scaling) by 2D pick and drag operations. Interaction is not restricted to single objects but can be applied to compound objects as well. The method described in this paper is an easy‐to‐understand 3D input technique which does not require any special hardware and is compatible with the designer's mental model of object manipulation.
FISCAL POLICY AND AGGREGATE CONSUMPTION: NEW EVIDENCE FROM THE UNITED STATES
Authors: Darby Julia , Malley Jim 
Published: October 2007

AbstractIn this paper we estimate the marginal rate of substitution between aggregate per‐capita consumption and per‐capita government expenditure on goods and services using US quarterly data over the period 1953 to 1993. This estimate is an important input to any attempt to assess the overall effectiveness of fiscal policy since it directly affects the size of the fiscal policy multiplier. Other recent consumption studies which incorporate the effects of government expenditure have failed to establish a stable estimate of the marginal rate of substitution. We argue that this failure results from imposing the unrealistic assumption that this parameter is constant. In contrast, we allow the marginal rate of substitution to depend on both the level and composition of government spending.
SIR JAMES STEUART'S STATESMAN REVISITED IN LIGHT OF THE CONTINENTAL INFLUENCE1
Authors: Redman Deborah 
Published: October 2007

AbstractThe author assesses the influence Continental thought had on Sir James Steuart and places him in the Continental setting in order to understand his most controversial message, his theory of the state, and how it differed from that of his contemporaries, above all from Adam Smith's
GROSS EXPENDITURE ON UK INDUSTRIAL ASSISTANCE: A RESEARCH NOTE
Authors: Wren Colin 
Published: October 2007

AbstractThis note presents annual figures for gross expenditure on UK central government assistance to industry over the period 1960‐90. This is part of onging research on the determinants and effects of UK industrial assistance. All figures are at corrent prices and a breakdown is provided between various components of policy, comprising national assistance, industrial and firm specific assistance, technology support, civil aircraft aid, shipbuilding assistance and local employment and regional policy.
R&D COMPETITION WITH ASYMMETRIC FIRMS
Authors: Poyago‐Theotoky Joanna 
Published: October 2007

AbstractThis paper considers a non‐tournament duopoly model of process innovation. Costs of production can be reduced by firms spending on R&D. Firms are asymmetric in the sense that they may differ in their initial costs of production. It is shown that the high‐cost firm may spend more (or less) in R&D than its low‐cost rival. This main result is dependent on the relative magnitude of two important forces: the incentive effect, whereby the low‐cost firm always has a stronger incentive to spend on cost‐reducing R&D, and the effectiveness factor, which favours the high‐cost firm.