bluuebunny/crossref_metadata_2025 huggingface dataset:
Child Emotionality and Maternal Responsiveness as Predictors of Reunion Behaviors in the Strange Situation: Links Mediated and Unmediated by Separation Distress
Authors: Kochanska Grazyna , Coy Katherine C.
Published: March 2003

Children’s emotionality‐fear, anger, and joy‐observed outside of the relationship with the mother (in standard laboratory paradigms), and within that relationship (in mother‐child interactions), and mothers’ responsiveness, all at 9 and 14 months, were examined as predictors of the reunion behaviors in the Strange Situation at 14 months in 112 children. Many predictors were linked to the reunion behaviors, but most of those relations were at least partially mediated by children’s separation distress, which itself strongly predicted the reunion behaviors. Those relations were no longer significant when distress was controlled. Several links, however, remained significant, and they were unmediated by distress: Almost all involved measures assessed within the context of the mother‐child relationship. In particular, possible markers of a suboptimal relationship (children’s dampened joy and increased anger in interactions with the mother, poor maternal responsiveness) were associated with more avoidance and resistance upon reunion, even after accounting for the strong impact of distress. Studying how factors measured outside of and within early relationships influence the components of the attachment system may foster understanding of child behavior in the Strange Situation.
How Children Use Input to Acquire a Lexicon
Authors: Hoff Erika , Naigles Letitia
Published: March 2003

The contributions of social processes and computational processes to early lexical development were evaluated. A re‐analysis and review of previous research cast doubt on the sufficiency of social approaches to word learning. An empirical investigation of the relation of social–pragmatic and data‐providing features of input to the productive vocabulary of sixty‐three 2‐year‐old children revealed benefits of data provided in mother–child conversation, but no effects of social aspects of those conversations. The findings further revealed that the properties of data that benefit lexical development in 2‐year‐olds are quantity, lexical richness, and syntactic complexity. The nature of the computational mechanisms implied by these findings is discussed. An integrated account of the roles of social and computational processes to lexical development is proposed.
Parent–Daughter Transmission of the Androgen Receptor Gene as an Explanation of the Effect of Father Absence on Age of Menarche
Authors: Comings David E. , Muhleman Donn , Johnson James P. , MacMurray James P.
Published: March 2003

Based on an evolutionary theory of socialization, Belsky and colleagues proposed that girls exposed to a stressful environment, especially when due to father absence in the first 7 years of life, showed an early onset of puberty, precocious sexuality, and unstable relationships as adults. The authors of this article examined an alternative explanation that a variant X–linked androgen receptor (AR) gene, predisposing the father to behaviors that include family abandonment, may be passed to their daughters causing early puberty, precocious sexuality, and behavior problems. The results of a study of 121 White males and 164 White females showed a significant association of the short alleles of the GGC repeat polymorphism of the AR gene with a range of measures of aggression and impulsivity, increased number of sexual partners, sexual compulsivity, and lifetime number of sex partners in males; and paternal divorce, father absence, and early age of menarche in females. These findings support a genetic explanation of the Belsky psychosocial evolutionary hypothesis regarding the association of fathers’ absence and parental stress with early age of onset of menarche and early sexual activity in their daughters. A genetic explanation of the father absence effect is proposed in which fathers carrying the AR alleles are more likely to abandon a marriage (father absence) and pass those alleles to their daughters in whom they produce an earlier age of menarche and behavioral problems.
Relationally and Physically Aggressive Children’s Intent Attributions and Feelings of Distress for Relational and Instrumental Peer Provocations
Authors: Crick Nicki R. , Grotpeter Jennifer K. , Bigbee Maureen A.
Published: March 2003

Numerous studies have demonstrated that physically aggressive children exhibit hostile attributional biases in response to instrumental peer provocations, a social information–processing pattern that has been recognized as a contributor to peer–directed aggression. The present studies (N= 127 and N= 535) were designed to extend past research by evaluating the intent attributions and feelings of emotional distress of relationally and physically aggressive children in response to instrumental and relational provocation contexts. Results indicated that physically aggressive children exhibited hostile attributional biases and reported relatively greater distress for instrumental provocation situations, whereas relationally aggressive children exhibited hostile attributional biases and reported relatively greater distress for relational provocation contexts. Implications of these findings for the understanding of factors that may contribute to relational as well as physical aggression are discussed.
Who’s in the House? Race Differences in Cohabitation, Single Parenthood, and Child Development
Authors: Dunifon Rachel , Kowaleski–Jones Lori
Published: March 2003

This study examined four questions: (1) How does family structure (specifically, single parenthood, married parent, and cohabitating parent) affect children’s delinquency and math test scores? (2) Do these effects differ by race? (3) Do parenting practices mediate the links between family structure and children’s outcomes? and (4) Does this mediation differ by race? Unlike some previous work in this area, the present study distinguished between the effects of single parenthood and cohabitation. Using fixed–effects techniques to control for unobserved heterogeneity between children in the various family structures, single parenthood was found to be associated with reduced well–being among European American children, but not African American children. Cohabitation was associated with greater delinquency among African American children, and lower math scores among European American children. No evidence was found to indicate that parenting mediated the links between family structure and children’s outcomes. Finally, it was found that for African American children, measures of maternal warmth and the provision of rules had direct effects on children’s delinquency.
Continuity and Change in Inhibited and Uninhibited Children
Authors: Pfeifer Marcie , Goldsmith H.H. , Davidson Richard J. , Rickman Maureen
Published: March 2003

After screening 368 toddlers and selecting 77 into extremely inhibited, extremely uninhibited, and intermediate groups, 63 children (82%) were followed up at 4 and 7 years. Minority subgroups of both the inhibited and uninhibited children showed continuity on outcomes consisting of questionnaire measures of shyness, inhibitory control, and impulsivity, as well as multiepisode observational measures of behavioral inhibition and exuberance. Change from both inhibited and uninhibited status from the toddler age was more common than remaining extremely inhibited or uninhibited, but that change was largely constrained to the middle of the distribution.
A Market–Driven Model for Designing Negotiation Agents
Authors: Sim Kwang Mong
Published: March 2003

Although there are many extant agent–based systems for negotiation in e–commerce, the negotiation strategies of agents in these systems are mostly static. This article presents a model for designing negotiation agents that make adjustable rates of concession by reacting to changing market situations. To determine the amount of concession for each trading cycle, these market–driven agents are guided by four mathematical functions of eagerness, trading time, trading opportunity, and competition. Trading opportunity is determined by considering: (i) number of trading partners, (ii) spreads—differences in utilities between an agent and its trading partners, and (iii) probability of completing a deal. Competition is determined by the probability that an agent is not considered the most preferred trader by other negotiating parties. Motivated by factors such as corporate policies and resource needs, eagerness represents an agent’s desire to complete a deal. Agents with different time sensitivity to deadlines employ different trading strategies by making different rates of concession at different stages of negotiation. In this article, three classes of strategies with respect to remaining trading time are discussed. Theoretical analyses show that market–driven agents are designed to make prudent and appropriate amounts of concession for a given market situation.
Frontiers in User‐Computer Interaction
Authors: Van Dam Andries
Published: March 2003

In this age of (near‐)adequate computing power, the power and usability of the user interface is as key to an application’s success as its functionality. Most of the code in modern desktop productivity applications resides in the user interface. But despite its centrality, the user interface field is currently in a rut: the WIMP (Windows, Icons, Menus, Point‐and‐Click GUI based on keyboard and mouse) has evolved little since it was pioneered by Xerox PARC in the early ’70s. Computer and display form factors will change dramatically in the near future and new kinds of interaction devices will soon become available. Desktop environments will be enriched not only with PDAs such as the Newton and Palm Pilot, but also with wearable computers and large‐screen displays produced by new projection technology, including office‐based immersive virtual reality environments. On the input side, we will finally have speech‐recognition and force‐feedback devices. Thus we can look forward to user interfaces that are dramatically more powerful and better matched to human sensory capabilities than those dependent solely on keyboard and mouse. 3D interaction widgets controlled by mice or other interaction devices with three or more degrees of freedom are a natural evolution from their two‐dimensional WIMP counterparts and can decrease the cognitive distance between widget and task for many tasks that are intrinsically 3D, such as scientific visualization and MCAD. More radical post‐WIMP UIs are needed for immersive virtual reality where keyboard and mouse are absent. Immersive VR provides good driving applications for developing post‐WIMP UIs based on multimodal interaction that involve more of our senses by combining the use of gesture, speech, and haptics.
Interactive 3D Morphing
Authors: Bao Hujun , Peng Qunsheng
Published: March 2003

A new 3D morphing algorithm for polyhedral objects with the same genus is presented in the paper. Our main contribution is an efficient and general algorithm for setting up the vertex correspondence between the polyhedra. The proposed algorithm first interactively partitions the two original polyhedra into the same number of polygonal patches, the patch correspondence is also established during partitioning. Each pair of corresponding patches is then parametrized and resampled by using the harmonic maps. A feature polyhedron is finally constructed for each original polyhedron, and the vertex correspondence between each original polyhedron and its feature polyhedron is automatically established following a cluster scheme. The shape transition between the original polyhedral models is accomplished by composing three successive transformations using their feature polyhedra as the bridges. Experimental results demonstrate that our algorithm is very robust, and can deal with very general cases (non‐zero genus polyhedral cases).
A Framework for Synchronized Editing of Multiple Curve Representations
Authors: Grimm Cindy , Ayers Matthew
Published: March 2003

Editing curves and surfaces is difficult in part because their mathematical representations rarely correspond to most people’s idea of a curve or surface. The implementation (and hence, behavior) of most manipulation tools is intertwined with a particular curve or surface representation; this can make reimplementing the tool with a different representation problematic. A system using a single representation must therefore either limit the types of tools available or convert existing tools to work on the system’s representation.

In this paper we present a framework for editing curves or surfaces which supports multiple representations and ensures that they stay synchronized. As a proof of concept, we have created a curve editor which contains several tools each of which manipulate one of three different curve representations: polylines, NURBs, and multi‐resolution B‐splines.
Accelerated Walkthroughs of Virtual Environments Based on Visibility Preprocessing and Simplification
Authors: Wang Yigang , Bao Hujun , Peng Qunsheng
Published: March 2003

This paper proposes a new preprocessing method for interactive rendering of complex polygonal virtual environments. The approach divides the space that observer can reach into many rectangular viewpoint regions. For each region, an outer rectangular volume (ORV) is established to surround it. By adaptively partitioning the boundary of the ORV together with the viewpoint region, all the rays that originate from the viewpoint region are divided into the beams whose potentially visible polygon number is less than a preset threshold. If a resultant beam is the smallest and intersects many potentially visible polygons, the beam is simplified as a fixed number of rays and the averaged color of the hit polygons is recorded. For other beams, their potentially visible sets (PVS) of polygons are stored respectively. During an interactive walkthrough, the visual information related to the current viewpoint is retrieved from the storage. The view volume clipping, visibility culling and detail simplification are efficiently supported by these stored data. The rendering time is independent of the scene complexity.
Space Discretization for Efficient Human Navigation
Authors: Bandi Srikanth , Thalmann Daniel
Published: March 2003

There is a large body of research on motion control of legs in human models. However, they require specification of global paths in which to move. A method for automatically computing a global motion path for a human in 3D environment of obstacles is presented. Object space is discretized into a 3D grid of uniform cells and an optimal path is generated between two points as a discrete cell path. The grid is treated as graph with orthogonal links of uniform cost. A* search method is applied for path finding. By considering only the cells on the upper surface of objects on which human walks, a large portion of the grid is discarded from the search space, thus boosting efficiency. This is expected to be a higher level mechanism for various local foot placement methods in human animation.
Importance Driven Halftoning
Authors: Streit L. , Buchanan J.
Published: March 2003

Most halftoning techniques have been primarily concerned with achieving an accurate reproduction of local gray‐scale intensities while avoiding the introduction of artifacts. A secondary concern in halftoning has been the preservation of edges in the halftoned image. In this paper, we will introduce a new halftoning technique that utilizes a bandpass pyramid to achieve an accurate reproduction of important attributes in the image. Ink is distributed through the bandpass pyramid primarily according to a user defined importance function. This technique has three main characteristics. First, our technique can produce results similar to many other halftoning techniques by allowing a generic importance function to be specified. If the chosen importance function is average intensity we obtain results similar to traditional halftoning. We also show how the importance function can be changed to highlight areas with high variance. Second, in addition to changing the importance function, the drawing primitives can also be changed. By using line segments instead of single pixels as drawing primitives we illustrate how edge enhancement can be achieved. Third, this technique allows the user to easily limit the number drawing primitives used. This is useful in limited resource rendering.

In addition to providing a tailorable halftoning technique our method can easily be adapted to produce two tone non‐photorealistic (NPR) images. We illustrate this by showing how sketched effects can be achieved by aligning the drawing primitives according to different image attributes.
An Exhaustive Error‐Bounding Algorithm for Hierarchical Radiosity
Authors: Holzschuch Nicolas , Sillion François
Published: March 2003

This paper presents a complete algorithm for the evaluation and control of error in radiosity calculations. Providing such control is both extremely important for industrial applications andd one of the most challenging issues remaining in global illumination research. In order to control the error, we need to estimate the accuracy of the calculation while computing the energy exchanged between two objects. Having this information for each radiosity interaction allows to allocate more resources to refine interactions with greater potential error, and to avoid spending more time to refine interactions already represented with sufficient accuracy. Until now, the accuracy of the computed energy exchange could only be approximated using heuristic algorithms. This paper presents the first exhaustive algorithm to compute fully reliable upper and lower bounds on the energy being exchanged in each interaction. This is accomplished by computing first and second derivatives of the radiosity function where appropriate, and making use of two concavity conjectures. These bounds are then used in a refinement criterion for hierarchical radiosity, resulting in a global illumination algorithm with complete control of the error incurred. Results are presented, demonstrating the possibility to create radiosity solutions with guaranteed precision. We then extend our algorithm to consider linear bounding functions instead of constant functions, thus creating simpler meshes in regions where the function is concave, without loss of precision. Our experiments show that the computation of radiosity derivatives along with the radiosity values only requires a modest extra cost, with the advantage of a much greater precision.
Nonphotorealistic Rendering by Q‐mapping
Authors: Hall P.
Published: March 2003

We present Q‐mapping which is a technique for rendering three‐dimensional objects using nonphotorealistic cues, by applying Q‐maps. Q‐maps are three‐dimensional textures that make marks on objects, and thus provide visual cues for shape, shade, and texture. Q‐maps adapt to light intensity, typically by making more marks in darker areas. Q‐maps can produce images with a very wide range of visual styles (e.g. half tone shading, and pen‐and‐ink colour wash). The primary contribution is that these styles reside in a single parametric space. Importantly this space includes photorealism as a style, which is therefore regarded as a special case of nonphotorealistic image rendering in general. We illustrate our explanation of Q‐mapping using examples from scientific visualisation and computer graphics – and provide a gallery of images to show the versatility of the approach.
Creating Architectural Models from Images
Authors: Liebowitz David , Criminisi Antonio , Zisserman Andrew
Published: March 2003

We present methods for creating 3D graphical models of scenes from a limited numbers of images, i.e. one or two, in situations where no scene co‐ordinate measurements are available. The methods employ constraints available from geometric relationships that are common in architectural scenes – such as parallelism and orthogonality – together with constraints available from the camera. In particular, by using the circular points of a plane simple, linear algorithms are given for computing plane rectification, plane orientation and camera calibration from a single image. Examples of image based 3D modelling are given for both single images and image pairs.
An Adaptive Method for Area Light Sources and Daylight in Ray Tracing
Authors: Zaninetti Jacques , Boy Pierre , Peroche Bernard
Published: March 2003

This paper proposes an adaptive method for taking both (diffuse or not) planar area light sources and daylight into account in a ray tracing environment which separates the calculation of direct and indirect illumination. In a given point, direct illumination due to a light source or to natural light is represented by a vector, the direction and magnitude of which being computed through an adaptive area approach, which is driven by the solid angle according to which a part of the source is seen from the current point. In the case of unoccluded diffuse polygonal sources, an analytical formula is used which gives an exact value for this vector.
Texture‐based Dither Matrices
Authors: Veryovka Oleg , Buchanan John
Published: March 2003

Continuous tone images must be halftoned to be displayed on binary output devices such as printers. Halftoning algorithms at low resolutions of the output hardware introduce textures into the resulting display. In this work we control halftoning texture by generating a threshold matrix from an image‐based texture. We demonstrate that processing textures by the adaptive histogram equalization algorithm approximates pixel distribution properties of traditional dither screens. Ordered dithering with the resulting threshold matrix enables us to define texture in the halftoned image. We control the appearance of this texture by a combination of the ordered dither algorithm with an error diffusion process. We present applications of texture‐based dither screens to both photorealistic and artistic rendering. In the case of photorealistic tone reproduction our technique preserves textures and edges of the original image. The ability to define an arbitrary texture enables us to introduce a variety of artistic effects, including embossing of images with textures and text, and approximation of the appearance of of conventional illustration media. We evaluate the resulting halftoning using multi‐scale edge distortion measures. Our quantitative evaluation closely corresponds to the visual observations.
Using an Intermediate Skeleton and Inverse Kinematics for Motion Retargeting
Authors: Monzani Jean‐Sébastien , Baerlocher Paolo , Boulic Ronan , Thalmann Daniel
Published: March 2003

In this paper, we present a new method for solving the Motion Retargeting Problem, by using an intermediate skeleton. This allows us to convert movements between hierarchically and geometrically different characters. An Inverse Kinematics engine is then used to enforce Cartesian constraints while staying as close as possible to the captured motion.
Tone Reproduction for Interactive Walkthroughs
Authors: Scheel A. , Stamminger M. , Seidel H.‐P.
Published: March 2003

When a rendering algorithm has created a pixel array of radiance values the task of producing an image is not yet completed. In fact, to visualize the result the radiance values still have to be mapped to luminances, which can be reproduced by the used display. This step is performed with the help of tone reproduction operators. These tools have mainly been applied to still images, but of course they are just as necessary for walkthrough applications, in which several images are created per second. In this paper we illuminate the physiological aspects of tone reproduction for interactive applications. It is shown how tone reproduction can also be introduced into interactive radiosity viewers, where the tone reproduction continuously adjusts to the current view of the user. The overall performance is decreased only moderately, still allowing walkthroughs of large scenes.
Web‐Based Remote Renderingwith IBRAC (Image‐Based Rendering Acceleration and Compression)
Authors: Yoon I. , Neumann U.
Published: March 2003

Recent advances in Internet and computer graphics stimulate intensive use and development of 3D graphics on the World Wide Web. To increase efficiency of systems using 3D graphics on the web, the presented method utilizes previously rendered and transmitted images to accelerate the rendering and compression of new synthetic scene images. The algorithm employs ray casting and epipolar constraints to exploit spatial and temporal coherence between the current and previously rendered images. The reprojection of color and visibility data accelerates the computation of new images. The rendering method intrinsically computes a residual image, based on a user specified error tolerance that balances image quality against computation time and bandwidth. Encoding and decoding uses the same algorithm, so the transmitted residual image consists only of significant data without addresses or offsets. We measure rendering speed‐ups of four to seven without visible degradation. Compression ratios per frame are a factor of two to ten better than MPEG2 in our test cases. There is no transmission of 3D scene data to delay the first image. The efficiency of the server and client generally increases with scene complexity or data size since the rendering time is predominantly a function of image size. This approach is attractive for remote rendering applications such as web‐based scientific visualization where a client system may be a relatively low‐performance machine and limited network bandwidth makes transmission of large 3D data impractical.
Variable Resolution 4‐k Meshes: Concepts and Applications
Authors: Velho Luiz , Gomes Jonas
Published: March 2003

In this paper we introduce variable resolution 4‐k meshes, a powerful structure for the representation of geometric objects at multiple levels of detail. It combines most properties of other related descriptions with several advantages, such as more flexibility and greater expressive power. The main unique feature of the 4‐k mesh structure lies in its variable resolution capability, which is crucial for adaptive computation. We also give an overview of the different methods for constructing the 4‐k mesh representation, as well as the basic algorithms necessary to incorporate it in modeling and graphics applications.
Filtered Jitter
Authors: Klassen R. Victor
Published: March 2003

Jitter is one popular way of generating samples for stochastic sampling in computer graphics. The Poisson disk distribution better approximates that of the human photomosaic. In this paper we examine the spatial and frequency space behaviour of a number of existing algorithms for generating stochastic samples and propose a new algorithm based on low pass filtering a jittered set of displacements. The distribution is at least as much like that of the human photomosaic as any existing algorithm, while being fast to compute.
Control of Feature‐point‐driven Facial Animation Using a Hypothetical Face
Authors: Su Ming‐Shing , Ko Ming‐Tat , Cheng Kuo‐Young
Published: March 2003

A new approach to the generation of a feature‐point‐driven facial animation is presented. In the proposed approach, a hypothetical face is used to control the animation of a face model. The hypothetical face is constructed by connecting some predefined facial feature points to create a net so that each facet of the net is represented by a Coon’s surface. Deformation of the face model is controlled by changing the shape of the hypothetical face, which is performed by changing the locations of feature points and their tangents. Experimental results show that this hypothetical‐face‐based method can generate facial expressions which are visually almost identical to those of a real face.
Interactive Display of Global Illumination Solutions for Non‐diffuse Environments – A Survey
Authors: Heidrich Wolfgang
Published: March 2003

In recent years there has been a lot of work on interactively displaying global illumination solutions for non‐diffuse environments. This is an extremely active field of research, in which a lot of different approaches have recently been proposed. In this survey, we will discuss and compare these. This will hopefully prepare the ground for systematically addressing the open questions in the future.
An Open Model for Hypermedia and Its Application to Geographical Information Systems
Authors: Hall W. , Simmons D.
Published: March 2003

This paper describes the design and implementation of a multimedia information management environment that is based on an open model for hypermedia. The model, known as Microcosm, is currently implemented in Microsoft Windows and supports many different media types. The open nature of the model and the separation of the links from the data, allows links to be applied across any application running under Windows or the OS/2 version 2 desktop, thus creating a truly integrated environment. One example, which is, discussed in the paper, is the integration of a hypermedia database with a geographical information system. The paper also discusses the application of novel interfaces to dynamic media within a hypermedia system, including the use of moving icons (micons).
SX/Tools ‐ An Open Design Environment for Adaptable Multimedia User Interfaces
Authors: Kühme Thomas , Schneider‐Hufschmidt Matthias
Published: March 2003

In this paper a brief review of user interface management systems (UIMSs) and their advantages is given. Shortcomings of current UIMSs and open requirements imposed by industrial application areas are outlined. Among the most important requirements are uniform design mechanisms independent of interaction media, techniques, and styles as well as a straight forward end‐user adaptability of user interfaces.

A new approach to interactive interface construction, called “direct composition”, is introduced. In this approach all interface objects contain the means for their own modification and design and therefore offer consistent interaction techniques for both the construction and usage of user interfaces. Moreover, end‐user adaptability is an inherent feature of direct composition interfaces.

The user interface design environment SX/Tools is described to exemplify specific properties of user interface management systems following the principle of direct composition. The impacts of direct composition on user interface design include a uniform interface development process covering tool development, interface development, and “on‐usage” interface adaptation. It is argued that the direct composition approach can overcome many of the problems with traditional UIMSs.
Affine Texture Mapping and Antialiasing Using Integer Arithmetic
Authors: Nehlig P. , Ghazanfarpour D.
Published: March 2003

Texture mapping techniques are very useful for generating more realistic images. However, texture compression, generally induced by geometric transformations, is at the origin of aliasing artifacts especially the well‐known “moire” patterns. Two discrete affine texture mapping methods based exclusively on integer arithmetic are presented here. This original approach of discrete affine mapping is adequate for antialiasing in the case of compressed textures.
Composing Hierarchically Structured Images
Authors: Patterson John W. , Cockton Gilbert
Published: March 2003

This paper begins by examining the ‘classical’ raster‐based composition model, establishing its weakness, and developing a new composition algebra based on line drawing. It then examines the role of composition in the Hierarchical Display Model, demonstrates that the forms of composition assumed in this model are inadequate to deal correctly with the interactions of two‐dimensional representations of three‐dimensional objects, and shows that our composition algebra resolves this difficulty. The composition steps required can be packaged with the use of a single attribute which constrains the apparent order of composition. This attribute is associated with the object which is to be taken ‘out of order’, obviating any needsfor layers.
A CAD System for Color Design of a Car
Authors: Oshima Tetsuya , Yuasa Shinji , Sakanoshita Ken‐ichi , Ogata Yoshinori
Published: March 2003

We have developed a color CAD system which enables a color designer to evaluate and create body colors of a car on a graphic display and put this system into practical use. The system has three features; generating realistic images comparable to photography to satisfy the car designer's needs, through close analysis of the physical phenomena taking place in the real environment, reproducing the desired colors very accurately on a CRT monitor, through analysis of the CRT colorimetric characteristics of reproducing the specified colors in response to the input signals, and utilizing a parallel computer to generate realistic images at a high speed and to control colors through interactive operation. Application of the CAD system reported here to the field of color design made it possible to fully evaluate and create body colors by means of computer graphics, replacing the conventional method which requires the painting of clay models or prototype cars.
An Efficient Adaptive Algorithm for Constructing the Convex Differences Tree of a Simple Polygon
Authors: Rappoport Ari
Published: March 2003

The convex differences tree (CDT) representation of a simple polygon is useful in computer graphics, computer vision, computer aided design and robotics. The root of the tree contains the convex hull of the polygon and there is a child node recursively representing every connectivity component of the set difference between the convex hull and the polygon. We give an O(n log K + K log2 n) time algorithm for constructing the CDT, where n is the number of polygon vertices and K is the number of nodes in the CDT. The algorithm is adaptive to a complexity measure defined on its output while still being worst case efficient. For simply shaped polygons, where K is a constant, the algorithm is linear. In the worst case K = O(n) and the complexity is O(n log2 n). We also give an O(n log n) algorithm which is an application of the recently introduced compact interval tree data structure.
Hidden Surface Elimination on Parallel Processors
Authors: Highfield Julian C. , Bez Helmut E.
Published: March 2003

With the wide availability of general purpose parallel computers, there is a need to reconsider hidden surface elimination (HSE) algorithms with respect to parallel implementation. This paper considers MIMD parallel implementations off our common image space HSE algorithms ‐ recursive subdivision, scan line, painter's, and z‐buffer. Their suitability for parallel implementation is investigated and their relative performance in multiprocessor systems is measured using polygonal scene descriptions of between 200 and 2500 polygons. Dependence on the size of scene description is measured and results are extrapolated to larger scene descriptions. It is shown that HSE algorithms may be efficiently parallelised. A distributed z‐buffer is shown to be a fast and efficient method of solving HSE problems using parallel computers.
A Dynamic Gesture Language and Graphical Feedback for Interaction in a 3D User Interface
Authors: Bordegoni Monica , Hemmje Matthias
Published: March 2003

In user interfaces of modern systems, users get the impression of directly interacting with application objects. In 3D based user interfaces, novel input devices, like hand and force input devices, are being introduced. They aim at providing natural ways of interaction. The use of a hand input device allows the recognition of static poses and dynamic gestures performed by a user's hand.

This paper describes the use of a hand input device for interacting with a 3D graphical application. A dynamic gesture language, which allows users to teach some hand gestures, is presented. Furthermore, a user interface integrating the recognition of these gestures and providing feedback for them, is introduced. Particular attention has been spent on implementing a tool for easy specification of dynamic gestures, and on strategies for providing graphical feedback to users' interactions. To demonstrate that the introduced 3D user interface features, and the way the system presents graphical feedback, are not restricted to a hand input device, a force input device has also been integrated into the user interface.
Parallel 3D Delaunay Triangulation
Authors: Cignoni P. , Montani C. , Perego R. , Scopigno R.
Published: March 2003

The paper deals with the parallelization of Delaunay triangulation algorithms, giving more emphasis to pratical issues and implementation than to theoretical complexity. Two parallel implementations are presented. The first one is built on De Wall, an Ed triangulator based on an original interpretation of the divide & conquer paradigm. The second is based on an incremental construction algorithm. The parallelization strategies are presented and evaluated. The target parallel machine is a distributed computing environment, composed of coarse grain processing nodes. Results of first implementations are reported and compared with the performance of the serial versions running on a Unix workstation.
A Paradigm for the Robust Design of Algorithms for Geometric Modeling
Authors: Agrawal Amitabh , Requicha Aristides A. G.
Published: March 2003

Geometric modelers are becoming faster and more powerful, but they still suffer from reliability problems because of floating point errors. Previous work in the field of robust geometric modeling tends to be problem specific and has proven hard to generalize. The approach described here is a general paradigm for handling the accuracy problem for a large set of geometric algorithms. This approach brings together ideas and techniques from interval arithmetic, constraint management, randomization, and algebraic geometry. It acknowledges that input values have tolerances, that objects within tolerance are equivalent, and that certain geometric singularities must be maintained because they reflect design intent or the laws of geometry. Our approach is systematic, and can be applied almost mechanically to the large domain of problems that can be solved by algorithms using the operations +, −, * and /. The required theory and algorithms have been developed, and the viability of the concepts has been demonstrated by an experimental implementation involving linear half‐spaces in Euclidean 2‐dimensional space. The implementation focuses on algorithms for computing the boundaries of objects defined by Constructive Solid Geometry (CSG) trees.
A New Approach to the Construction of Surfaces from Contour Data
Authors: Jones Mark W. , Chen Min
Published: March 2003

This paper presents a new approach to the construction of a surface from a stack of contour slices. Unlike most existing methods, this new approach handles ambiguous conditions consistently without employing an algorithm to establish a correspondence between vertices on one contour and those on the next. It is easy to implement and fast to compute, requiring only basic geometric properties, namely closedness and simplicity, to be available with contour data. The advantages of this new approach have also been demonstrated with solutions to a few classical problems from the literature and some practical problems in medical imaging. It can also be applied to geographical surveying and keyframe animations.
Skylight for Interior Lighting Design
Authors: Dobashi Yoshinori , Kaneda Kazufumi , Nakashima Takanobu , Yamashita Hideo , Nishita Tomoyuki , Tadamura Kastumi
Published: March 2003

It is inevitable for indoor lighting design to render a room lit by natural light, especially for an atelier or an indoor pool where there are many windows. This paper proposes a method for calculating the illuminance due to natural light, i.e. direct sunlight and skylight, passing through transparent planes such as window glass. The proposed method makes it possible to efficiently calculate such illuminance accurately, because it takes into account both non‐uniform luminous intensity distribution of skylight and the distribution of transparency of glass according to incident angles of light. Several examples including the lighting design in an indoor pool, are shown to demonstrate the usefulness of the proposed method.
Vector Fields: an Interactive Tool for Animation, Modeling and Simulation with Physically Based 3D Particle Systems and Soft Objects
Authors: Hilton Travis L. , Egbert Parris K.
Published: March 2003

Vectorfields have traditionally been used in computer graphics as a means of visualizing models over time. This paper presents a system which extends the use of vector fields as an interactive tool for physically based three dimensional particle systems and soft objects. The techniques implemented in the system provide the user with new flexibility in animation, modeling and simulation. This paper describes bounded interactive vectorfields and how they can be used to manipulate particle systems and a class of soft objects. Applications to animation, modeling and simulation are also presented.
PREMO ‐ An Initial Approach to a Formal Definition
Authors: DUCE D.A. , DUKE D.J. , ten HAGEN P.J.W. , REYNOLDS G.J.
Published: March 2003

Many descriptions of multimedia programming systems are starting to appear in the literature, but little work has yet been done on how to formally specify and reason about such systems. This paper is a contribution on the use of formal description techniques for the specification of multimedia systems and explores a style in which the Object‐Z notation from the University of Queensland can be used to specify some of the properties and functionality of such systems. The work has been carried out with reference to the role of formal description techniques in the presentation of ISO/IEC International Standards and in particular to the Premo project in ISO/IEC JTCl/SC24.
An All‐integer Algorithm for Drawing Anti‐aliased Straight Lines
Authors: Kui Liu Yong
Published: March 2003

An algorithm for drawing anti‐aliased straight lines based on Bresenharn'sline algorithm is presented in this paper. Only integer calculations are required. Multiplications or divisions are not needed (only simple addition/subtraction and sign testing are used). The algorithm can be used to choose between 2n intermediate grey levels between black and white.
Corporate Governance in a Charity
Authors: Vinten Gerald
Published: March 2003

This article considers notions of accountability and governance in the charitable sector. It suggests a model of accountability based on a case study of a well known, but anonymous charity. The opportunities for voluntary bodies are increasing and more state funds are becoming available; but with them comes a demand for more public accountability. A definition of accountability is proposed and the extent of the charity’s compliance discussed. From this inventory of compliance, conclusions are drawn as to reforms needed in the charity’s structure and management if it is to become more in tune with its environment.
Remuneration Disclosure in Australia and the United States
Authors: Hill Jennifer
Published: March 2003

This précis is from Research Paper #1/96, by Jennifer Hill, and published by the Australian Investment Managers’ Association, 1996. It supplements, as a matter of record, the conclusions of the UK report of a study group chaired by Sir Richard Greenbury, and published in Corporate Governance – an international review.
Separate, But Not Independent: Board Leadership Structure in Large Corporations
Authors: Daily Catherine M. , Dalton Dan R.
Published: March 2003

Board activists continue to suggest – even demand – that the CEO and board chairperson positions be held separately, to ensure governance independence at board level. A regression analysis of large corporations provides no evidence of differences in independence across a range of dimensions. Even when the positions are held separately, the chairperson is often the former CEO, holds substantial equity in the firm and, in many cases, has familial ties to current executives.
Handing over the reins: should the CEO’s successor be an insider or an outsider?
Authors: Clutterbuck David
Published: March 2003

This paper is based on an extract from an extensive study of high performance companies around the world, published in July 1997 under the title The Winning Streak, Mark II. The study focused on 24 companies from nine countries, where interviews were carried out with top management and beyond; and a further seven companies from four countries, where data was collected from extensive literature search and/or more limited interviews. All of the internationally operating companies had a long track record of significantly better financial performance and most had a higher public reputation than competitors in their industries. A control group of less successful companies was used to test the findings of the study, as was an “action case study” of a high performance company losing its way.

The overall study identified a number of critical issues that these companies all managed well and concluded that maintaining high performance was due in large part to the organisation’s ability to balance conflicting demands within each of those issues. One of the issues concerned succession at the top: was continued high performance best achieved by an internal appointment that sustained the same values, or by introducing new blood at timely points in the organisation’s evolution? By far the majority of companies preferred to appoint from within, making the succession as seamless as possible by:

•building a high degree of strategic consensus among the top team, from whom the new CEO will be chosen

•ensuring that potential CEOs brought in from outside spend long enough in the company to understand how it works

•using the retiring CEO as a chairman‐mentor
Corporate Governance in Small Companies – the Alternative Investment Market
Authors: Mallin Chris , Ow‐Yong Kean
Published: March 2003

This paper examines corporate governance in small companies listed on the Alternative Investment Market (AIM) which was established in the UK in 1995. The London Stock Exchange rules stipulate that each company wishing to join AIM must have a nominated advisor and broker. The nominated advisor is seen as playing a key role in AIM companies, enjoying an ongoing advisory relationship as well as playing a monitoring role. The presence of the nominated advisor may, in some ways, mean that less emphasis is placed on formal corporate governance structures, as the nominated advisor does have a close relationship with the company it advises.

The formal aspects of corporate governance are analysed in terms of disclosures in the admission document put forward by AIM companies coming to market. Preliminary findings suggest AIM companies brought onto the market by a nominated advisor who also acts as the nominated broker pay more attention to the Cadbury Code on corporate governance. Also, the study suggests AIM companies raising no new capital on admission possess relatively weaker corporate governance structures.

The success of AIM, with over 240 companies having joined in the first 18 months of its existence, means that our findings have implications for policy‐makers involved in corporate governance not only in the UK but also for those involved in the establishment of markets for small companies in a global context.