bluuebunny/crossref_metadata_2025_split huggingface dataset:
Moving Picture Synthesis at Linkoping University
Authors: Fahlander Olov 
Published: October 2007

AbstractWe believe that in the future we will see a diverse variety of applications in the now emerging technology of real time computer animation. Such animations impose stringent computational and bandwidth demands on the underlying system. It is important to investigate carefully the methods best suited to the particular requirements of animation when motion is involved.1,2,3 In this paper we describe a system ‐ Retina ‐ which is now operational. We discuss the underlying concept of parameterization, which is of fundamental importance to the software design. Some timing data for this system will be given. A short description of the 3D editor, which is currently under development, is also given.
Multiprocessor Ray Tracing
Authors: Cleary John G. , Wyvill Brian M. , Birtwistle Graham M. , Vatti Reddy 
Published: October 2007

AbstractA multiprocessor algorithm for ray tracing is described. The performance of the algorithm is analysed for a cubic and square array of processors with only local communication between near neighbours. Theoretical expressions for the speedup of the system as a function of the number of processors are derived. These analytic results are supported by simulations of ray tracing on a number of simple scenes with polygonal surfaces. It is found that a square network of processors generally performs better than a cubic network. Some comments are made on the construction of such a system using current (1985) microprocessor technology.
A Geometric Modeller Based on the Exact Octtree Representation of Polyhedra
Authors: Navazo I. , Avala D. , Brunet P. 
Published: October 2007

AbstractGeometric Modellers based on a Boundary Representation scheme are well suited for display operations, but boolean operations require algorithms with quadratic complexity. Using a class of extended octtrees which is presented here, boolean operations become linear, while exact recomputation of the boundary model in the case of polyhedral objects is possible, and memory requirements are less than in classical octtree encodings. Some bounds on the memory savings are given and discussed. The DMI system, a Geometric Modeller based on a hybrid model Boundary ‐ Extended Octtrees, is presented, discussing the main operations and the interface between both models. Some modelling examples are shown. Finally, a generalization of the extended octtree encoding which allows the exact representation of objects limited by sculptured surfaces is presented.
A Method of Displaying Transformed Picture Rectangles Using GKS Raster Functions
Authors: Schumann H. , Kotzauer A. 
Published: October 2007

AbstractThe GKS raster functions Fill Area and Cell Array allow area primitives in Computer Graphics to be used in a GKS environment.In implementing these functions, the computing time and memory required are important factors in deciding their usability especially for interactive work. The trend in the implementation of algorithms for such primitives is to use specialized hardware.In this paper, algorithms are introduced which are suitable for computers of low and middle efficiency and provide a sufficient image quality and an acceptable response time for dialogues.
The Priority Tree, a HL/HSR Approach for PHIGS
Authors: Abi‐Ezzi S.S. 
Published: October 2007

AbstractThe Programmer's Hierarchical Interactive Grahics System (PHIGS) specifies an interface for programming device‐independent computer graphics applications. PHIGS provides a powerful data grouping mechanism, called the PHIGS structure, that may be used to model the geometry of 3D objects. Hidden Line/Hidden Surface Removal (HL/HSR) is a required process to produce realistic solid views of the modeled objects. Modeling clip is an essential process for viewing a clipped portion of the modeled objects. A technique is presented that provides HL/HSR and modeling clip as added utilities to PHIGS. The technique is based on the Binary Space Partitioning (BSP) tree (sometimes called priority tree), and involves a back to front sorting of the primitives of a PHIGS structure network to another PHIGS structure. Modeling clip is achieved by limiting the sorting to those primitives in a specified clip ping region of the object space. The resulting structure when displayed on a raster device produces a realistic view of the possibly clipped object that was originally modeled by the PHIGS structure network.
An Economic High Performance Pixel Memory with 3‐D Solids Capability
Authors: Belch F.R. 
Published: October 2007

AbstractFor economic raster graphics equipment capable of the display of high resolution dynamic pictures of 3‐D solids, 3‐D wire frames, and 2‐D wire frames ‐ in decreasing order of stringency, the design of the pixel memory system is a key issue, due to the high pixel writing speeds required. This paper discusses some new architectural possibilities for such a memory system.To give some idea of problem scale, present investigations indicate that pixel generation rates from an economic tiling circuit of up to 25 Mhz may be possible ‐ 40 ns per pixel. However, using contemporary dynamic RAM'S memory read‐modify‐write cycle, including computation on the data read from the memory (for example masking in the new pixel data or z‐depth‐buffer arithmetic) may take 400 ns i.e. a speed difference of about 10:l exists.The matching of these differing data rates demands a departure from traditional pixel memory architecture. Here a possible philosophy of approach is discussed together with the results of a simulation study. The proposed architecture is able to keep costs, bulk and power consumption down by using cheap, industry standard, high density memory components. Its use is additionally shown to be compatible with the generation of dynamic views of bolids using depth buffer methods.
A Simple and Efficient Haloed Line Algorithm for Hidden Line Elimination
Authors: Franklin W.R , Akman V. 
Published: October 2007

AbstractAn efficient algorithm, HALO, is given to compute haloed line drawings of wire frame objects. Haloed line drawings are described by Appel et al.1HALO has two parts: CUT and DRAW. CUT uses an adaptive grid to find all edge intersections. It overlays a square grid, whose fineness is a function of the number and length of the edges, on the Scene. It determines the cells that each edge passes through, sorts these by cell to obtain the edges in each cell, and then, in each cell, tests each pair of edges in that cell for intersection. For broad classes of input this takes time linear in the number of edges plus the number of intersections. CUT writes a file containing all the locations where each edge is crossed in front by another. Given a halo width, DRAW reads this file edge by edge. For each edge, it subtracts and adds the halo width to each intersection to get the locations where the edge becomes invisible and visible. It sorts these along the edge, and then traverses the edge, plotting those portions where the number of “Visible” transitions is equal to the number of “invisible” transitions. DRAW takes time hear in the number of edge segments. Dividing HALO into two parts means that redrawing a plot with a different halo width is fast, since only DRAW need to be rerun.CR Categories and Subject Descriptions: I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling ‐ geometric algorithm, languages, and systems; F.2.2 [Analysis of Algorithms and Problem Complexity]: Nonnumerid Algorithms and Problems ‐geometrical problem and computationsGeneral Terms: Algorithms, design.
New Methods for Improving the GKS Fill Area Output Primitive
Authors: Herman Ivan , Reviczky Janos 
Published: October 2007

AbstractThe fill area primitive is one of the most powerful primitives of GKS and its derivatives (GKS‐3D, PHIGS etc.). Since its specrfication is extremely general, it is important to explore new approaches to achieve higher performance in its implementation. In this paper fast algorithms are presented for special situations, which can be included, together with appropriate tests, into a complete GKS output pipeline. As a result, a speed improvement With a factor of two may be achieved in important practical cases.
Evaluation of Standard Graphics Packages
Authors: Klok Fopke 
Published: October 2007

AbstractIn order to compare the quality of different implementations of GKS, the ISO0 standard for computer graphics, an evaluation method for GKS implementations is presented. It is based upon several groups of criteria. One group of criteria is concerned with performance, by which we understand here the memory requirements and time requirements for programs using GKS functions. A program that measures the performance of GKS packages is presented. Results of this evaluation method with several commercially available GKS implementations are described in summary. A checklist for evaluation of standard graphics packages is added as an appendix.
SIGHT‐A Dedicated Computer Graphics Machine
Authors: Naruse Tadashi , Yoshida Masaharu , Takahashi Tokiichiro , Naito Seiichiro 
Published: October 2007

AbstractThe. architecture of, and a performance estimate for, the dedicated graphics processor ‐ SIGHT, a high‐speed ray tracing machine, are presented. Ray tracing is a vector calculation in 3–dimensional (3–D) space and each ray to be traced can be calculated independently. The SIGHT is designed so that it speeds up the execution of the ray tracing algorithm at two levels of parallel operations: the pixel‐level parallel operation by multiprocessors and the instruction‐level parallel operation by the new processing element (PE) architecture. The features of the PE are:
A Prolog Environment for GKS‐Based Graphics
Authors: Milanese V. 
Published: October 2007

AbstractThe Prolog language and GK.S are considered in an integrated fashion in order to create a flexible graphics environment. Prolog descriptive properties are devoted to creating hierarchical schemata which can be instantiated on application data, validated against topological constraints, and handled and drawn, at a low level, by GKS primitives.
Experience with Chisl, a Configurable Hierarchical Interface Specification Language
Authors: Wood C.A. , Gray P.D. , Kilgour A.C. 
Published: October 2007

AbstractThis paper describes the design, implementation and initial evaluation of a graphical dialogue specification language and its interpreter. Features of the system include a hierarchical dialogue structure with the capability to export options to lower levels of the hierarchy, the use of a restricted form of production rule approach to option selection in each unit of the dialogue, and suspended time editing (allowing modification of the dialogue specification during execution without loss of context).
Theoretical Developments on Polygonal Approximation of Parametric Surfaces for Ray Tracing
Authors: Bouatouch Kadi 
Published: October 2007

AbstractSome theoretical extensions are brought to Koparkar and Mudur's method which deals with a polygonal approximation of parametric surfaces using potential extrema. The proposed extensions allow the determination of both the existence and the equation of a curve solution of potential extrema. Solutions are given to solve the crack problem and to avoid the artificats due to an inexact ray‐surface intersection point near the silhouette or on the higher curvature regions. Moreover, two methods of ray tracing surfaces are proposed.
A Processor for an Object‐Oriented Rendering System
Authors: Schneider Bengt‐Olaf 
Published: October 2007

AbstractAn object oriented approach to the real‐time rendering of raster images is described. The architecture is based on a set of object processors arranged in a pipeline. These object processors scan convert the objects in the scene and interpolate depth and normal vectors across the objects. Hidden surface elimination is distributed along the pipeline. The structure of the object processors and of the algorithms employed are described in detail.Computing Reviews Classification: C. 1.2, C.3, 1.3.1
A Top Down Method for Interactive Drawing
Authors: Slater Mel 
Published: October 2007

AbstractTraditional interactive drawing programs adopt a bottom‐up approach, allowing the user to construct a picture by the use of discrete tools, for example, lines, circles, rectangles, and so on. This paper presents a different approach, which allows users to construct graphical objects by stretching and cutting existing objects. The representation is simply implemented, based on a ring of cubic Bezier curves, and use of the de Casteljau algorithm.
The Controller Animation System
Authors: John Nigel W. , Willis Philip J. 
Published: October 2007

AbstractOne of the ways in which computer animation can be generated is to use interactive graphics systems. In this paper we describe Controller, an animation system of this type. We concentrate on the operation of Controller and detail how an animator can plan and choreograph the motion of objects and cameras. We have intended to provide a system that gives the animator as much control as possible subject to keeping die interface simple to operate.
Notes on the Mathematics of the PHIGS Viewing Pipeline
Authors: Krammer Gergely 
Published: October 2007

AbstractIt is well known that homogeneous linear matrix transformations of the projective space may be efficiently used for the representation and the execution of common geometrical transformations but the general class of such transformations include also matrices which may cause numerical problems by transforming certain finite geometrical objects to infinity Different methods have been developed for handling such cases and this paper presents a new one called‘UW clipping’which is based on some interesting properties of projective transformations. Furthermore the paper introduces die concept of ‘conic sectors’ as a generalisation to half‐planes and halfspaces respectively, with the invariance property that such sectors are mapped onto other such sectors by projective transformations, and thus enable the transformation of clipping halfplanes and halfspaces. Finally the possibility of transforming die rectangular clipping box into the object space is investigated.
The Douglas‐Peucker Algorithm for Line Simplification: Re‐evaluation through Visualization
Authors: Visvalingam M. , Whyatt J. D. 
Published: October 2007

AbstractThe primary aim of this paper is to illustrate the value of visualization in cartography and to indicate that tools for the generation and manipulation of realistic images are of limited value within this application. This paper demonstrates the value of visualization within one problem in cartography, namely the generalisation of lines. It reports on the evaluation of the Douglas‐Peucker algorithm for line simplification. Visualization of the simplification process and of the results suggest that the mathematical measures of performance proposed by some other researchers are inappropriate, misleading and questionable.
TECHNOLOGY GAPS BETWEEN RICH AND POOR COUNTRIES*
Authors: Streeten Paul 
Published: October 2007

SummaryWe have started by asking the question: why are there international income inequalities? We have ascribed them to differences in applied productive knowledge. This raised the question: why can productive knowledge be communicated and diffused within an advanced nation but not between nations or within underdeveloped nations? What are the obstacles to the international diffusion of benefits?We have found these in two areas: obstacles to communication and absence of suitable technologies. The obstacles to communication can again be divided into those due to costs of transfer and those due to intentional restrictions or the exercise of monopoly power. But even perfect communication would not meet the need for quite different technologies from those developed in high‐income countries.Measures that reduce the Communications Gap might make the Suitability Gap wider and vice versa, but a set of integrated actions attacking both gaps has a chance of success. Technical knowledge cannot be marketed like other products or factors because it possesses peculiar features: (i) indivisibility, (ii) inappropriatability, (iii) embodiment in other factors, (iv) uncertainty and (v) impossibility to know its full value until bought. Policies for closing the two gaps are interdependent, so that the pursuit of any one in isolation might make matters worse. What is needed is a set of integrated actions, attacking both the Communications Gap and the Suitability Gap. Transfer must be supplemented by indigenous capability; adaptation by invention and innovation.
MANAGEMENT BEHAVIOUR AND A THEORY OF DIVERSIFICATION
Authors: Sutton C. J. 
Published: October 2007

This paper investigates the basis for a behavioural theory of diversification. A theory of diversification may be required (i) for full analysis of competitive processes, which include innovation and cross‐entry competition, and (ii) to understand the selection of diversification projects in individual firms. Alternative optimising and non‐optimising models are feasible. The choice between these alternatives will be considered after the non‐optimising model has been developed.Section I outlines the basic model and the general predictions which it generates. In section II the predictions are subjected to a coarse test, which is taken to justify further investigation of the model's properties. The model is developed more fully in section III.
A HIERARCHICAL THEORY OF THE FIRM*
Authors: SANDLER TODD , CAULEY JON 
Published: October 2007

SummaryThis paper provides a mathematically coherent and concise formulation of the Williamson market‐failure approach and, hence, develops models for single‐level and multilevel firms and organizations. These models optimally determine the extent of integration for each viable link on every hierarchical level, When the models are reformulated in terms of four operational parameters that determine integration, applied benefit‐cost methods can be utilized, in practice, to model a firm. Both static and dynamiclmodels‐are presented.
EFFECTIVE DEMAND, OUTWARD INVESTMENT AND THE (THEORY OF THE) TRANSNATIONAL CORPORATION: AN EMPRICAL INVESTIGATION
Authors: Pitelis Christos 
Published: October 2007

AstractThat demand‐side deficiencies can provide an inducement for outward investment by transnational corporations has never acquired much currency, despite its long history and the fact that existing theories ofter have implications supportive of it. Arguably a reason for this is that the idea has never been tested empirically. In this paper we provide the first such empirical test. First we critically survey and attempt to synthesize the mainstream microeconomic or supply‐side theories of the TNC. Then we examine the case for a demand‐side perspective, link this to the supply‐side and discuss some existing indirect evidence in support of this perspective. Finally we provide a direct econometric test of the demand‐side perspective, which provides clear support for it.
HOW THEORY CAME TO ENGLISH CLASSICAL ECONOMICS*
Authors: Coleman William O. 
Published: October 2007

AbstractThe confidently theoretical method of English classical economics is traced to the Enlightenment's struggle to resolve the disputes between rationalism and anti‐rationalism which had dominated the 17th century. It is argued that, in an attempt to resolve these disputes, several Enlightenment authors, including David Hume and Dugald Stewart, sought to unite empiricism with the notion of law‐like universe by arguing that economic laws are no more than general facts apparent from everyday life. This position, by denying that theory had any connection with the hypothetical, the instrumental or the abstract, blurred the distinction between theory and fact, and taught Classical economists to see their theorising as fact. This position thereby gave the Classical economists licence to pursue their theoretical speculations, free from any doubts or uncertainties about their theorising.
US FOREIGN EXCHANGE MARKET INTERVENTION SINCE 1962
Authors: Schwartz Anna J. 
Published: October 2007

AbstractThe Federal Reserve has intervened in foreign exchange markets since 1962 as a partner of the Treasury's Exchange Stabilization Fund. Departing from its scripted passive role under the Bretton Woods system, the US defense of the dollar under pegged exchange rates may not appear unreasonable. Why the practice continues under a floating rate system is harder to understand. By accumulating large foreign currency balances since 1987, the US has made intervention easier. Holding larger balances does not help the authorities know what exchange rates ought to be. The US for a few years in the 1980s refrained from intervening. It can happen again if its authorities acknowledge that intervening is an exercise in futility.
Masked Popery and Pyrrhonian Uncertainty: The Early Scottish Covenanters on Arminianism
Authors: Mullan David G. 
Published: October 2007

In Jacobean and Caroline Scotland there was little Arminianism to be found, whether in its Remonstrant (Dutch) or Laudian (English) versions. Nevertheless, the representation of this teaching by a few Scottish divines, its more strenuous advocacy in England, and reports of its spread in Europe unnerved those who would lead the covenanting movement after 1638.Arminianism represented a two‐pronged threat to the Calvinist covenanting vision. Its attempt at moderation in the theological strife of the time approximated a compromise with, if not a surrender to, popery. But Arminianism also suffered from an identification with the scepticism then fermenting in European philosophy. The decay of a providential worldview undercut the national self‐image of Scotland at the forefront of resurgent Reformed religion. The significance of free will threatened the individual’s assurance of election. The loss of certainty about theological authority, accepting the individual’s right to interpret the Bible and to express his views publicly, shattered the ideal of a religiously uniform society. Thus considered, the persistent interest in Arminianism provides a useful perspective on the mind of the covenanting movement.
Non‐disjunction in trisomy 21: study of chromosomal heteromorphisms in 110 families
Authors: MIKKELSEN MARGARETA , POULSEN HANNE , GRINSTED JßRGEN , LANGE AKSEL 
Published: October 2007

SummaryQM variants on chromosome 21 and silver staining of NOR regions were applied in the study of non‐disjunction in 110 families from different parts of Denmark. In 76% of the families the study was informative. Paternal failures were observed in 11 % on Funen as compared 23.5% on Zealand. In one family, crossing‐over on the short arms of chromosome 21 in the mother and mitotic non‐disjunction of chromosome 21 was observed.Maternal first meiotic error predominates in both high maternal and low maternal age. Also in paternal non‐disjunction failures of first meiotic division predominate. Two maternally and one paternally originated cases of de novo translocations were observed.