bluuebunny/crossref_metadata_2025_split huggingface dataset:
Boolean Operations and Spatial Complexity of Face Octrees.
Authors: Pla‐Garcia Núria 
Published: March 2003

Abstract:Most of the existing representation schemes of free form surfaces or objects with free form boundary are not capable to compute efficiently boolean operations and other usual geometric interrogations. Classical octrees, proposed to overcome this drawback, require large amounts of memory. Face Octrees was a proposal suitable in the case of smooth surfaces or objects with smooth boundary. In this paper, different aspects of this model are discussed. In fact, it is focussed on the description of boolean operation algorithms using this model, proving that it solves the first problems, and on the computation of spatial complexity bounds. These bounds allow an evaluation of the fitness of each of the existing octree models in a given situation, showing the advantage of Face Octrees when the boundaries are smooth (curvatures are small).
A New Paradigm for Geometric Processing
Authors: Yamaguchi Fujio , Niizeki Masatoshi 
Published: March 2003

AbstractA new paradigm for geometric processing is proposed. The paradigm can be featured by the four key phrases: (1) Totally Four Dimensional Homogeneous Processing, (2) 4 × 4 Matrix Method and 4 × 4 Determinant Method, (3) Integer Arithmetic with Adaptive Data‐Length Control Technique, (4) Systematic Paradigm Structures Based on the Duality.
A Rendering Algorithm for Discrete Volume Density Objects
Authors: Blasi Philippe , Le Saec Bertrand , Schlick Christophe 
Published: March 2003

Abstract:We present a new algorithm for simulating the effect of light travelling through volume objects. Such objects (haze, fog, clouds…) are usually modelized by voxel grids which define their density distribution in a discrete tridimensional space. The method we propose is a two‐pass Monte‐Carlo ray‐tracing algorithm that does not make any restrictive assumptions neither about the characteristics of the objects (both arbitrary density distributions and phase functions are allowed) nor about the physical phenomena included in the rendering process (multiple scattering is accounted for). The driving idea of the algorithm is to use the phase function for Monte‐Carlo sampling, in order to modify the direction of the ray during scattering.
GKS‐9x: Some Implementation Considerations
Authors: Damnjanovic L.B. , Duce D.A. , Robinson S.K. 
Published: March 2003

AbstractThe Graphical Kernel System (GKS) was published as an ISO standard for computer graphics programming in August 1985. GKS is now undergoing revision in ISO/IEC and at the time of writing the text of the Draft International Standard of GKS‐9x was being finalized. This paper presents a way in which a key part of the new functionality in GKS‐9x, namely namesets and selection criteria, can be implemented effectively.
Cooperative Visualization of Computational Fluid Dynamics
Authors: Gerald‐Yamasaki Michael J. 
Published: March 2003

AbstractTempus Fugit/Interview is a computational fluid dynamics visualization application for which processing is distributed between high performance graphics workstations and supercomputers. Facilities are provided in the application for more than one user to view shared images creating a cooperative visualization environment. The way in which the computation is partitioned between the super computer and the workstations is critical to the capability of the application to present simultaneous, identical, animated images of fluid dynamics to more than one user.
The Method of Dynamic Palette Construction in Realistic Visualization Systems
Authors: Voloboj Aleksej G. 
Published: March 2003

AbstractThe paper describes the colour approximation problem and the method of dynamic palette construction is suggested for its solution. The method uses the graphic display palette based on the computed true colour of the individual picture. Some aspects of human colour perception are considered. Two metrics in colour space are introduced to estimate closeness of the suggested colour approximation. The method was applied to visualize 3D scenes generated by ray tracing.
A Fractal Method for Digital Elevation Model Construction and its Application to a Mountain Region
Authors: Brivio Pietro Alessandro , Marini Daniele 
Published: March 2003

AbstractThis paper presents and discusses the results of a methodology for the construction of Digital Elevation Models (DEM), based on mathematical principles of fractal geometry. Classical approaches to DEM are founded on numerical methods of interpolation or approximation of data extracted from contour lines of standard topographic maps. Fractal geometry opens a new and innovative approach in which the irregularity, erraticity and self similarity of fractal structures mimics at best the typical behaviour of high mountain profiles. The adoption of fractal methods requires the identification of the fractal dimension D for a given data set. The determination of the fractal dimension D can be achieved applying some special mathematical method on finite set of samples. Different methods. for D estimation are presented. Once the fractal dimension is given, it is possible to reconstruct a surface relief using different fractal methods which interpolate the original set of elevation data. Our research has also investigated two different interpolation methods, fBm and IFS, both confirming that the fractal approach is very well suited for high relief terrain modeling. Photo realistic rendering of the computed DEM allows to appreciate the quality of the reconstruction through visual inspection.
Beyond WYSIWYG: Display of Hidden Information in Graphics Editors
Authors: Schleich R. , Dürst M.J. 
Published: March 2003

AbstractGraphics editors such as computer aided design systems are complex and difficult to use. We attribute this to the fact that only a small part of the information is visible and therefore accessible and understandable. Only the graphics objects themselves are visible, but the relations between these objects remain hidden. We propose an effective way to visualise this information in the form of trees and graphs in so‐called structure browsers. A prototype implements this proposal based on an object‐oriented application framework for graphics editors.
A Semantics‐based Approach for the Design and Implementation of Interaction Objects
Authors: Paterno' F. , Leonardi A. 
Published: March 2003

AbstractAlthough tools for developing graphical user interfaces are becoming increasingly popular, they do not usually highlight precisely which key elements developers should take into account. This still entails considerable expertise in developing user interfaces. In this paper we present an approach to overcome these problems. Our approach is based on a model for interaction objects and a corresponding design space. This is supported by a toolkit where the available interaction objects are initially classified by their semantics whereas in most current toolkits they are investigated by their appearance. This facilitates designers and developers in identifying the interactors needed in order to obtain an Interactive System supporting user tasks.
Real Time Fitting of Hand‐Sketched Pressure Brushstrokes
Authors: Pudet Thierry 
Published: March 2003

AbstractA method is described for fitting the outline of hand‐sketched pressure brushstrokes with Bézier curves. It combines the brush‐trajectory model, in which a stroke is generated by dragging a brush along a given trajectory, with a fast curve fitting algorithm.The method has been implemented for a vector‐based drawing program in which the user draws with a cordless pressure‐sensitive stylus on a digitizing tablet. From the trajectory followed by the stylus, its associated pressure data, and a specified brush, a stroke of variable width is computed and displayed in real time.First, the digitized trajectory is fitted, thus removing noise. Then, from polygonal approximations of the fitted trajectory and the brush outline, a polygonal approximation of the stroke outline is computed. Working with polygonal approximations reduces computations to simple geometric operations and greatly simplifies the treatment of dynamic, pressure‐controlled brushes. Last, the polygonal approximation of the stroke outline is fitted. The result is a closed piecewise Bézier curve approximating the brushstroke outline to within an arbitrary error tolerance.Several examples of hand‐sketched drawings realized with this method are presented.
A Formal Approach to the Specification of Graphic Object Functions
Authors: Torres J.C. , Clares B. 
Published: March 2003

AbstractGraphic objects are an abstract mathematical model for graphic systems. The model is an algebraic approach to represent graphic information, which include modelling operations. This formalism require some method to describe normal graphic procedures, such as changing the object colour or texture mapping, as these procedures are essential to represent graphic processes.This paper extends the theory by introducing the concept of graphic object functions. A graphic object function transforms one graphic object into another, changing its visual appearance or its geometric properties. A formal definition of graphic functions is given, with a characterization of two special kinds of graphic object functions: filters and object transference functions. These two kinds of functions can be used to perform normal graphic operations, such as changing colours, texture mapping or clipping.Equivalence relationships between graphic objects induced by functions are also studied. These relationships establish an hierarchical structure on the graphic object set.
Fast Wavelet Radiosity Method
Authors: Pattanaik Sumanta N. , Bouatouch Kadi 
Published: March 2003

AbstractWavelet analysis has been found [1] to be very useful for functional representation and accurate global solution of radiosity. In radiosity we deal with functions in 2D and 4D spaces. Under such conditions, the biggest bottleneck in applying this wavelet analysis seems to be the large number of multidimensional inner products. In this paper, we propose (i) the use of interpolating wavelets for fast inner product computation and consequently for faster wavelet radiosity solution (ii) the use of hierarchical decomposition technique for determining the smoothness of the radiosity function for optimal adaptive subdivision.
Recovering a Smooth Boundary Representation from an Edge Quadtree and from a Face Octree
Authors: Pla‐Garcia N. 
Published: March 2003

AbstractThe Face Octrees are a representation scheme which is very suitable to represent both smooth free form surfaces and solids with smooth boundary, as well as, to perform operations among them. However, the Face Octree representation is non continuous, thus an algorithm to convert this model to a boundary representation can be necessary. The conversion algorithm makes the advantages of this scheme really significant. The current paper is involved in the conversion from the Face Octrees model to a smooth boundary representation. However, first the planar case is treated.
A New Real Time Geometric Transformation Matrix and its Efficient VLSI Implementation
Authors: Ng C. M. , Bustard D. W. 
Published: March 2003

AbstractThe geometric transformation of an image with irregular shapes from a source space to a target space requires a huge number of multiplications and additions for each pixel. Such a through put is impossible to deliver by any processor in real‐time. This paper presents a new transformation matrix which can be used toper form real‐time 2‐D geometric transformations economically. The implementation of the transformation engine that is used to execute the transformation matrix is also presented. Experimental results indicate that real‐time geometric transformations based on a 4 × 4 transformation mesh can be achieved with the use of the transformation engine. This real‐time transformation function is useful in warping and blending of images, and can be easily extended to perform irregular shape transformations with a large number of control points in the transformation mesh.
Colouration Issues in Computer Generated Facial Animation
Authors: Patel M. 
Published: March 2003

AbstractIn everyday interactions with one another we use the face for recognising people and for communicating with them. Despite the considerable amount of research into computer generated facial animation, one particular aspect, that of the colouration of the face appears to have been neglected. In this paper we address issues pertinent to the use of colour for both modelling the appearance of the face and for enhancing communication during facial expression and animation. Colouration is an integral part of the face, which helps in the recognition of faces as well as in the interpretation of the often subtle signals emitted by the human face.
Releasing executive directors for outside directorships – the governance implications
Authors: Ward Martin 
Published: March 2003

Sir Adrian Cadbury (1993), commenting on the Cadbury Report, highlights not only the importance placed on outside directors for improved governance but also three areas of concern, namely the appointments process, the availability and the independence of outside directors.The strengths required for the role of outside director in a quoted PLC are considerable, and suggests that outside directors of listed UK public limited companies require the skills and experience that only existing executive directors of similar PLCs are likely to possess. Release by companies of their directors for outside duties raises its own governance issues. Should shareholders rather than internal management approve such appointments? Who has the right to the director’s fees, the company or the individual? Based on the response of 33 companies, this research finds that a majority (73%) have formal policies covering these governance issues but that between companies there are numerous policy differences.
Social distance between workers: An application to Italian geographic areas
Authors: D'Ambrosio Conchita 
Published: March 2003

This paper is concerned with the measurement of social distance, clustering, or polarization between workers of a given society. This concept is fundamentally different from that of inequality and thus cannot be measured by any Lorenz consistent index. Similarly, it cannot be additively decomposed into within‐ and between‐group components using classical techniques. A new decomposition method is proposed and applied to Italian workers. The method provides an index that can be used both to calculate the distance between social groups classified according to worker characteristic and to track changes across time. The new method also reveals the factors that are reshaping the wage distribution and allows us to identify precisely where these effects are having their greatest impact.JEL classification: D30, D63, I32.
Trust versus illusion: What is driving demonetization in the former Soviet Union?
Authors: Marin Dalia 
Published: March 2003

The virtual economy argument for Russia suggests that barter allows the parties to pretend that the manufacturing sector is producing value added by enabling this sector to sell its output at a higher price than its market value. We confront this prediction with the actual pricing behaviour of industrial sectors in Ukraine in 1997. Based on the pricing data of 165 barter deals we find no systematic difference in the pricing behaviour in non‐cash transactions across sectors. What appears to matter for the pricing behaviour is whether the firm is on the selling or buying end of the barter transaction. We offer a model that sees this pricing behaviour as a mechanism to deal with the absence of trust and liquidity in the economy.JEL classification: D20, G30, O10, P30.
The euro for the Balkans?
Authors: Gros Daniel 
Published: March 2003

This paper makes the case for full euroization of the Balkans. It argues that the full adoption of the new currency, including the use of euro notes and coins, would bring important benefits for the countries in south east Europe. The key benefit of euroization would be the opportunity it would provide to radically reform and open the financial system, thus changing the equilibrium of the domestic political economy (by eliminating political influence over credit allocation). It also argues that the loss of seigniorage would be minor, but that there is no reason why the rich EU should benefit from this. Compensation for the loss of seigniorage would be technically easy to implement. Finally, the paper presents a small model that demonstrates how a devaluation might actually impair the debt‐servicing capacity of the government. This implies that the exchange rate cannot easily absorb shocks to the interest rate to be paid on external debt, or to the availability of capital for emerging markets in general. A deterioration in the availability of external capital might thus trigger extremely large exchange rate adjustments, which in turn can disrupt the domestic financial system. This should be an important consideration for such a highly indebted region.JEL classification: F33, F32.
Voucher Privatization: A detour on the road to transition?
Authors: Katz Barbara G. , Owen Joel 
Published: March 2003

We explore an overlooked aspect of the design of the Czech voucher privatization programme, namely, the consequences of allowing individuals to distribute their vouchers among the voucher privatization funds (VPFs). We develop and analyse a model of voucher privatization in which we study the problem facing individuals who invest their vouchers in VPFs which, in turn, are able to use their skills to alter the performances of the firms in which they acquire shares. The VPFs have different skills and, by their bids and subsequent joint ownership patterns, affect the performances of the firms in their funds. We show that even in the case in which voucher holders have identical and full information, and wish to allocate their vouchers to the VPFs in a manner consistent with the maximization of economy–wide profit, a coordination failure generally prevents the implementation of this efficient outcome. Uncertainty, as well as differing payouts by the VPFs, is shown to exacerbate the problem. We conclude that there was an inherent flaw in the design of the Czech voucher scheme.JEL classification: D44, L33, P21, G11.
The participation of Russian households in the informal economy: Evidence from the VTsIOM data
Authors: Kim Byung–Yeon 
Published: March 2003

This study presents the size and structure of secondary employment in Russia, analyses the determinants of Russian informal secondary employment, and discusses differences between job qualifications in a main job and those in a secondary job. We estimate that 27 percent of Russia’s GDP was produced in the informal economy during 1997–98 and informal secondary employment amounts to about 20 percent of value added produced in the informal economy. We found that the probability of holding an informal secondary job as opposed to a formal one is positively associated with higher wage rates and lower education. However, there is little evidence that low income is correlated with holding an informal secondary job. We also found evidence that an informal secondary job requires lower job qualifications as compared to a formal one. Again, low income is not significant in determining differences between job qualifications in a main job and those in a secondary job.JEL classification: J22, J24, O17, P20.
Appointing and Censuring the European Commission: The Adaptation of Parliamentary Institutions to the Community Context
Authors: Magnette Paul 
Published: March 2003

The parliamentary model at the heart of European civic cultures has deeply influenced ‘Constitutional reforms’ in the European Community. But the EC is not a Parliamentary state and the transplant of national institutions in its own political context gives rise to hybrid practices. This paper examines this process of hybridation, and shows that new practices of appointment and censure are emerging in the Community, mixing classic parliamentary institutions with the crucial features of the EC itself. Focusing on recent tensions between the Council, the Commission, and the European Parliament, it shows that they are governed by national divisions, technocratic and legal reasoning rather than by classic majoritarian attitudes. It concludes that, while this new model of accountability might prove efficient in terms of inter‐institutional controls, it remains symbolically inefficient, because it does not help citizens understand and accept the Community institutional model.
Towards Industrial Application of Intelligent Training Systems
Authors: Bertin Alberta , Buciol Fabio , Stefanini Alberto 
Published: March 2003

Computer‐based training is an area where knowledge‐based techniques enable us to achieve new system functionalities which cannot be attained with conventional techniques. Knowledge‐based training systems can adapt the course, the lesson and the instructional strategy to the needs and attitude of the individual trainee, so as to obtain a completely individualised instruction. Due to these capabilities they are known as Intelligent Training Systems (ITSs). After their introduction in the mid‐eighties with their first successful application in the military sector, ITSs are now mature enough for practical use in civil applications.This paper presents the experience gained by the authors over the last decade through the realisation of two industrial prototypes in different sectors and the recent development of a full‐scale application. Such experience led to a specification methodology and to a development framework which now provide a solid baseline for the industrial application of the ITS technology.
A case‐based reasoning approach for building a decision model
Authors: Lee Jae Kwang , Kim Jae Kyeong 
Published: March 2003

A methodology based on case‐based reasoning is proposed to build a topological‐level influence diagram. It is then applied to a project proposal review process. The formulation of decision problems requires much time and effort, and the resulting model, such as an influence diagram, is applicable only to one specific problem. However, some prior knowledge from the experience in modeling influence diagrams can be utilized to resolve other similar decision problems. The basic idea of case‐based reasoning is that humans reuse the problem‐solving experience to solve new problems.In this paper, we suggest case‐based decision class analysis (CB‐DCA), a methodology based on case‐based reasoning, to build an influence diagram. CB‐DCA is composed of a case retrieval procedure and an adaptation procedure. Two measures are suggested for the retrieval procedure, one a fitting ratio and the other a garbage ratio. The adaptation procedure is based on decision‐analytic knowledge and decision participants' domain‐specific knowledge. Our proposed methodology has been applied to an environmental review process in which decision‐makers need decision models to decide whether a project proposal is accepted or not. Experimental results show that our methodology for decision class analysis provides decision‐makers with robust knowledge‐based support.
The State of the Union: Sexuality in American History
Authors: Pearsall Sarah M. S. 
Published: March 2003

Books reviewed in this article:Merril D. Smith (ed.), Sex and Sexuality in Early AmericaBeryl Satter, Each Mind a Kingdom: American Women, Sexual Purity, and the New Thought Movement, 1875–1920Sharon R. Ullman, Sex Seen: The Emergence of Modern Sexuality in AmericaM. E. Melody and Linda M. Peterson, Teaching America about Sex: Marriage Guides and Sex Manuals from the Late Victorians to Dr Ruth