bluuebunny/crossref_metadata_2025 huggingface dataset:
Renal graft survival is not influenced by a positive flow B‐cell crossmatch
Authors: Bryan Christopher F , Wakefield Mark , Reese Jeffrey C , Shield Charles F , Warady Bradley A , Winklhofer Franz T , Murillo Daniel
Published: December 2006

Abstract: Introduction: The influence of a positive B‐cell crossmatch on graft outcome in renal transplantation is controversial.

Methods: We analyzed graft survival using Kaplan–Meier estimates for recipients of deceased donor kidneys who were either regraft transplant patients (n = 198) from 1990 to August 20, 2004, or primary transplant patients (n = 361) from December 15, 2000 to August 8, 2004, each of whom had a flow T‐ and B‐cell IgG crossmatch performed before transplantation. The flow B‐cell crossmatch (FBXM) was not used to decide whether or not to transplant. Graft survival was analyzed by whether the patient's FBXM was positive or negative. We also evaluated creatinine levels and graft survival of 131 transplant patients (June 1, 2004 to July 1, 2005) by their FBXM result and by their HLA class II flow‐defined IgG PRA.

Results: One‐ and three‐yr graft survival for the primary transplant patient group with a positive FBXM (98% and 84%) was not significantly different from the group with a negative FBXM (96% and 93%) (log‐rank = 0.9). Similarly, graft survival at one, five, and 10 yr for the regraft transplant group whose FBXM was positive (91%, 76%, and 61%) was not significantly different from the group whose FBXM was negative (91%, 79%, and 77%) (log‐rank = 0.4). Creatinine levels in the group of patients whose FBXM was positive (1.4 ± 0.4 mg/dL; n = 76) were not significantly different from the group with a negative FBXM (1.4 ± 0.4 mg/dL; n = 42). Even in the presence of class II PRA, a positive FBXM did not impact a patient's creatinine levels or graft outcome.

Conclusion: Neither short nor long‐term graft survival of deceased donor kidneys is influenced by a positive flow B‐cell IgG crossmatch, even when caused by HLA class II antibody.
Psychological well‐being in adults transplanted in childhood
Authors: De Castro Elisa Kern , Moreno‐Jiménez Bernardo , Rodríguez‐Carvajal Raquel
Published: December 2006

Abstract:  Few studies have explored the long‐term psychological effects on young adults of childhood transplants. The aim of the present work was to examine psychological adaptation related to self‐concept, self‐esteem and subjective well‐being in young adults who had undergone solid organ transplantation in childhood. Twenty‐four adults transplanted in childhood participated in the study (13 of them received kidney transplants, five heart transplants and six liver transplants). Participants were of both sexes, aged 18–22, and were selected from three public hospitals in Madrid. The results reveal no differences in psychological adaptation according to the transplant type (kidney, heart, or liver), and a significant difference in negative affect between women and men (women present more negative affect than men). Hierarchical regression analysis, after controlling for possible confounding effects of demographic and clinical variables, showed the predictive power of self‐esteem to explain positive affect (60% of the total variance). Furthermore, physical self‐concept, health status and time on waiting list explain 71% of the negative affect variance. Our data suggest the importance of self‐esteem for the positive affect, and the power of clinical variables for the negative affect in young adults transplanted in childhood.
Low incidence of adverse events in outpatient pediatric renal allograft biopsies
Authors: Birk Patricia E. , Blydt‐Hansen Tom D. , Dart Allison B. , Kaita Lisa M. , Proulx Cynthia , Taylor Gerald
Published: December 2006

Abstract:  In 1999, our center implemented a policy of outpatient protocol biopsies as standard practice for the clinical management of pediatric renal allograft recipients. In order to determine the safety of this procedure, we conducted a retrospective chart audit of all outpatient renal allograft biopsies performed at our center. Biopsies were performed under conscious (midazolam) or procedural (propofol/fentanyl) sedation. Localization of the lower pole of the renal allograft was achieved with renal ultrasound. Using a Biopty gun with a 16‐gauge needle, two cores were obtained. Patients were discharged four h post‐biopsy. Patient demographics, hospital length of stay (LOS), specimen adequacy (per Banff criteria) and major and minor adverse events were recorded in a central database. Data were expressed as mean ± SD. From June 1999 to July 2004, we performed 162 biopsies in 43 pediatric renal allograft recipients. Most patients underwent extraperitoneal transplantation (42/43, 97.7%) and were greater than five yr of age at biopsy (129/131 biopsies, 98.5%). The majority of these procedures (131/162, 80.9%) were conducted in the outpatient department, with 113 of 131 (86.3%) being obtained for protocol (n = 89) and one‐month follow‐up acute rejection therapy (n = 24) indications. Patients underwent 3.7 ± 2.7 biopsies (range = 1–11). Specimen adequacy was achieved in 119 of 124 (96.0%) of documented cases. The overall incidence of adverse events was 12 of 131 (9.2%) biopsies, all of which were minor in severity. Macroscopic hematuria was the most common minor adverse event, occurring after 11 of 131 (8.4%) biopsies. While macroscopic hematuria prolonged LOS (adverse events vs. no adverse events: 23.0 ± 26.0 vs. 8.6 ± 4.1 h, p = 0), none of these episodes required major surgical or radiographic interventions. We conclude that in patients greater than five yr of age with extraperitoneal renal allografts, outpatient protocol biopsies using a 16‐gauge needle are sufficiently safe to justify their inclusion in the routine clinical management of pediatric renal allograft recipients and in pediatric clinical trials.
Easy Mesh Cutting
Authors: Ji Zhongping , Liu Ligang , Chen Zhonggui , Wang Guojin
Published: December 2006

We present Easy Mesh Cutting, an intuitive and easy‐to‐use mesh cutout tool. Users can cut meaningful components from meshes by simply drawing freehand sketches on the mesh. Our system provides instant visual feedback to obtain the cutting results based on an improved region growing algorithm using a feature sensitive metric. The cutting boundary can be automatically optimized or easily edited by users. Extensive experimentation shows that our approach produces good cutting results while requiring little skill or effort from the user and provides a good user experience. Based on the easy mesh cutting framework, we introduce two applications including sketch‐based mesh editing and mesh merging for geometry processing.

Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Geometric algorithms, languages, and systems
Accurate Specular Reflections in Real‐Time
Authors: Roger David , Holzschuch Nicolas
Published: December 2006

Specular reflections provide many important visual cues in our daily environment. They inform us of the shape of objects, of the material they are made of, of their relative positions, etc. Specular reflections on curved objects are usually approximated using environment maps. In this paper, we present a new algorithm for real‐time computation of specular reflections on curved objects, based on an exact computation for the reflection of each scene vertex. Our method exhibits all the required parallax effects and can handle arbitrary proximity between the reflector and the reflected objects.

Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism
Reflected‐Scene Impostors for Realistic Reflections at Interactive Rates
Authors: Popescu Voicu , Mei Chunhui , Dauble Jordan , Sacks Elisha
Published: December 2006

We present a technique for rendering reflections on complex reflectors at interactive rates based on approximating the geometry of the reflected scene with impostors. The reflections correctly convey the distance to the reflector surface and provide motion parallax. Two types of impostors are adapted to the reflections framework: billboards and depth maps. Billboards remove most of the problems of environment mapped reflections at only a small additional cost. Second order reflections are supported by introducing reflective billboards. Higher quality reflections that provide motion parallax within a reflected object are obtained by approximating the reflective geometry with depth maps. The computation of the intersection between a reflected ray and a depth map is accelerated by leveraging epipolar constraints. Like environment mapping, our technique does not pose any restriction on the geometry of the reflector, supports dynamic scenes, and runs at interactive rates with the help of graphics hardware.

Categories and Subject Descriptors (ACM CCS): I.3.3. [Computer Graphics]—Three‐Dimensional Graphics and Realism.
Multiresolution Random Accessible Mesh Compression
Authors: Kim Junho , Choe Sungyul , Lee Seungyong
Published: December 2006

This paper presents a novel approach for mesh compression, which we call multiresolution random accessible mesh compression. In contrast to previous mesh compression techniques, the approach enables us to progressively decompress an arbitrary portion of a mesh without decoding other non‐interesting parts. This simultaneous support of random accessibility and progressiveness is accomplished by adapting selective refinement of a multiresolution mesh to the mesh compression domain. We present a theoretical analysis of our connectivity coding scheme and provide several experimental results. The performance of our coder is about 11 bits for connectivity and 21 bits for geometry with 12‐bit quantization, which can be considered reasonably good under the constraint that no fixed neighborhood information can be used for coding to support decompression in a random order.

Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling
C‐BDAM – Compressed Batched Dynamic Adaptive Meshes for Terrain Rendering
Authors: Gobbetti E. , Marton F. , Cignoni P. , Di Benedetto M. , Ganovelli F.
Published: December 2006

We describe a compressed multiresolution representation for supporting interactive rendering of very large planar and spherical terrain surfaces. The technique, called Compressed Batched Dynamic Adaptive Meshes (C‐BDAM), is an extension of the BDAM and P‐BDAM chunked level‐of‐detail hierarchy. In the C‐BDAM approach, all patches share the same regular triangulation connectivity and incrementally encode their vertex attributes using a quantized representation of the difference with respect to values predicted from the coarser level. The structure provides a number of benefits: simplicity of data structures, overall geometric continuity for planar and spherical domains, support for variable resolution input data, management of multiple vertex attributes, efficient compression and fast construction times, ability to support maximum‐error metrics, real‐time decompression and shaded rendering with configurable variable level‐of‐detail extraction, and runtime detail synthesis. The efficiency of the approach and the achieved compression rates are demonstrated on a number of test cases, including the interactive visualization of a 29 gigasample reconstruction of the whole planet Earth created from high resolution SRTM data.

Categories and Subject Descriptors (according toACMCCS): I.3.3 [Computer Graphics]: Picture and Image Generation; I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism.
Texture Adaptation for Progressive Meshes
Authors: Chen Chih‐Chun , Chuang Jung‐Hong
Published: December 2006

Level‐of‐detail modeling is a vital representation for real‐time applications. To support texture mapping progressive meshes (PM), we usually allow the whole PM sequence to share a common texture map. Although such a common texture map can be derived by using appropriate mesh parameterizations that consider the minimization of geometry stretch, texture stretch, or even the texture deviation introduced by edge collapses, we have found that even with a well parameterized texture map, the texture mapped PM still reveals apparent texture distortion due to geometry changes and the nature of linear interpolation used by texture mapping hardware. In this paper, we propose a novel, simple, and efficient approach that adapts texture content for each edge collapse, aiming to eliminate texture distortion. A texture adaptation and its inverse are local and incremental operations that can be fully supported by texture mapping hardware, the render‐to‐texture feature, and the fragment shader. Once the necessary correspondence in the partition of texture space is built during the course of PM construction, the texture adaptation or its inverse can be applied on the fly before rendering the simplified or refined model with texture map. We also propose the mechanism of indexing mapping to reduce blurred artifacts due to under‐sampling that might be introduced by texture adaptation.

Keywords: texture mapping progressive meshes, mesh simplification, mesh parameterization, texture distortion Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism Color, shading, shadowing, and texture
Optimizing Control Variate Estimators for Rendering
Authors: Fan Shaohua , Chenney Stephen , Hu Bo , Tsui Kam‐Wah , Lai Yu‐chi
Published: December 2006

We present the Optimizing Control Variate (OCV) estimator, a new estimator for Monte Carlo rendering. Based upon a deterministic sampling framework, OCV allows multiple importance sampling functions to be combined in one algorithm. Its optimizing nature addresses a major problem with control variate estimators for rendering: users supply a generic correlated function which is optimized for each estimate, rather than a single highly tuned one that must work well everywhere. We demonstrate OCV with both direct lighting and irradiance‐caching examples, showing improvements in image error of over 35% in some cases, for little extra computation time.

Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism Color, shading, shadowing, and texture G.3 [Probability and Statistics]: Probabilistic Algorithms

Keywords:

direct lighting, deterministic mixture sampling, control variates
A Predictive Light Transport Model for the Human Iris
Authors: W.Y. Lam Michael , V.G. Baranoski Gladimir
Published: December 2006

Recently, light interactions with organic matter have become the object of detailed investigations by image synthesis researchers. Besides allowing these materials to be rendered in a more intuitive manner, these efforts aim to extend the scope of computer graphics applications to areas such as applied optics and biomedical imaging. There are, however, organic materials that still lack predictive simulation solutions. Among these, the ocular tissues, especially those forming the human iris, pose the most challenging modeling problems which are often associated with data scarcity. In this paper, we describe the first biophysically‐based light transport model for the human iris ever presented in the scientific literature. The proposed model algorithmically simulates the light scattering and absorption processes occurring within the iridal tissues, and computes the spectral radiometric responses of these tissues. Its design is based on the current scientific understanding of the iridal morphological and optical characteristics, and it is controlled by parameters directly related to these biophysical attributes. The accuracy and predictability of the spectral results provided by the model are evaluated through comparisons with actual measured iridal data, and its integration into rendering frameworks is illustrated through the generation of images depicting iridal chromatic variations.

Categories and Subject Descriptors (according to ACM CCS): I.3.8 [Computer Graphics]: Applications
Bayesian Point Cloud Reconstruction
Authors: Jenke P. , Wand M. , Bokeloh M. , Schilling A. , Straßer W.
Published: December 2006

In this paper, we propose a novel surface reconstruction technique based on Bayesian statistics: The measurement process as well as prior assumptions on the measured objects are modeled as probability distributions and Bayes’ rule is used to infer a reconstruction of maximum probability. The key idea of this paper is to define both measurements and reconstructions as point clouds and describe all statistical assumptions in terms of this finite dimensional representation. This yields a discretization of the problem that can be solved using numerical optimization techniques. The resulting algorithm reconstructs both topology and geometry in form of a well‐sampled point cloud with noise removed. In a final step, this representation is then converted into a triangle mesh. The proposed approach is conceptually simple and easy to extend. We apply the approach to reconstruct piecewise‐smooth surfaces with sharp features and examine the performance of the algorithm on different synthetic and real‐world data sets.

Categories and Subject Descriptors (according to ACM CCS): I.5.1 [Models]: Statistical; I.3.5 [Computer Graphics]: Curve, surface, solid and object representations
Competing Fronts for Coarse–to–Fine Surface Reconstruction
Authors: Sharf Andrei , Lewiner Thomas , Shamir Ariel , Kobbelt Leif , Cohen–Or Daniel
Published: December 2006

We present a deformable model to reconstruct a surface from a point cloud. The model is based on an explicit mesh representation composed of multiple competing evolving fronts. These fronts adapt to the local feature size of the target shape in a coarse–to–fine manner. Hence, they approach towards the finer (local) features of the target shape only after the reconstruction of the coarse (global) features has been completed. This conservative approach leads to a better control and interpretation of the reconstructed topology. The use of an explicit representation for the deformable model guarantees water‐tightness and simple tracking of topological events. Furthermore, the coarse–to–fine nature of reconstruction enables adaptive handling of non‐homogenous sample density, including robustness to missing data in defected areas.

Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Digitizing and scanning.

Keywords: surface reconstruction, deformable models
Analysis of Reproducing Real‐World Appearance on Displays of Varying Dynamic Range
Authors: Yoshida Akiko , Mantiuk Rafał , Myszkowski Karol , Seidel Hans‐Peter
Published: December 2006

We conduct a series of experiments to investigate the desired properties of a tone mapping operator (TMO) and to design such an operator based on subjective data. We propose a novel approach to the tone mapping problem, in which the tone mapping parameters are determined based on the data from subjective experiments, rather than an image processing algorithm or a visual model. To collect this data, a series of experiments are conducted in which the subjects adjust three generic TMO parameters: brightness, contrast and color saturation. In two experiments, the subjects are to find a) the most preferred image without a reference image (preference task) and b) the closest image to the real‐world scene which the subjects are confronted with (fidelity task). We analyze subjects’ choice of parameters to provide more intuitive control over the parameters of a tone mapping operator. Unlike most of the researched TMOs that focus on rendering for standard low dynamic range monitors, we consider a broad range of potential displays, each offering different dynamic range and brightness. We simulate capabilities of such displays on a high dynamic range (HDR) display. This allows us to address the question of how tone mapping needs to be adjusted to accommodate displays with drastically different dynamic ranges.

Categories and Subject Descriptors (according to ACM CCS): I.3.8 [Computer Graphics]: High dynamic range images, Visual perception, Tone mapping
GPU‐based Collision Detection for Deformable Parameterized Surfaces
Authors: Greß Alexander , Guthe Michael , Klein Reinhard
Published: December 2006

Based on the potential of current programmable GPUs, recently several approaches were developed that use the GPU to calculate deformations of surfaces like the folding of cloth or to convert higher level geometry to renderable primitives like NURBS or subdivision surfaces. These algorithms are realized as a per‐frame operation and take advantage of the parallel processing power of the GPU. Unfortunately, an efficient accurate collision detection, that is necessary for the simulation itself or for the interaction with and editing of the objects, can currently not be integrated seamlessly into these GPU‐based approaches without switching back to the CPU. In this paper we describe a novel GPU‐based collision detection method for deformable parameterized surfaces that can easily be combined with the aforementioned approaches. Representing the individual parameterized surfaces by stenciled geometry images allows to generate GPU‐optimized bounding volume hierarchies in real‐time that serve as a basis for an optimized GPU‐based hierarchical collision detection algorithm. As a test case we applied our algorithm to the collision detection of deformable trimmed NURBS models, which is an important problem in industry. For the trimming and tessellation of the NURBS on the GPU we used a recent approach [GBK05] and combined it with our collision detection algorithm. This way we are able to render and check collisions for deformable models consisting of several thousands of trimmed NURBS patches in real‐time.

Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling—Geometric algorithms, languages, and systems; Splines; I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism—Virtual reality
A Robust Two‐Step Procedure for Quad‐Dominant Remeshing
Authors: Marinov Martin , Kobbelt Leif
Published: December 2006

We propose a new technique for quad‐dominant remeshing which separates the local regularity requirements from the global alignment requirements by working in two steps. In the first step, we apply a slight variant of variational shape approximation in order to segment the input mesh into patches which capture the global structure of the processed object. Then we compute an optimized quad‐mesh for every patch by generating a finite set of candidate curves and applying a combinatorial optimization procedure. Since the optimization is performed independently for each patch, we can afford more complex operations while keeping the overall computation times at a reasonable level. Our quad‐meshing technique is robust even for noisy meshes and meshes with isotropic or flat regions since it does not rely on the generation of curves by integration along estimated principal curvature directions. Instead we compute a conformal parametrization for each patch and generate the quad‐mesh from curves with minimum bending energy in the 2D parameter domain. Mesh consistency between patches is guaranteed by simply using the same set of sample points along the common boundary curve. The resulting quad‐meshes are of high‐quality locally (shape of the quads) as well as globally (global alignment) which allows us to even generate fairly coarse quad‐meshes that can be used as Catmull‐Clark control meshes.

Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Geometric algorithms, languages, and systems
Easy Matting ‐ A Stroke Based Approach for Continuous Image Matting
Authors: Guan Yu , Chen Wei , Liang Xiao , Ding Zi’ang , Peng Qunsheng
Published: December 2006

We propose an iterative energy minimization framework for interactive image matting. Our approach is easy in the sense that it is fast and requires only few user‐specified strokes for marking the foreground and background. Beginning with the known region, we model the unknown region as a Markov Random Field (MRF) and formulate its energy in each iteration as the combination of one data term and one smoothness term. By automatically adjusting the weights of both terms during the iterations, the first‐order continuous and feature‐preserving result is rapidly obtained with several iterations. The energy optimization can be further performed in selected local regions for refined results. We demonstrate that our energy‐driven scheme can be extended to video matting, with which the spatio‐temporal smoothness is faithfully preserved. We show that the proposed approach outperforms previous methods in terms of both the quality and performance for quite challenging examples.
Cross Dissolve Without Cross Fade: Preserving Contrast, Color and Salience in Image Compositing
Authors: Grundland Mark , Vohra Rahul , Williams Gareth P. , Dodgson Neil A.
Published: December 2006

Linear interpolation is the standard image blending method used in image compositing. By averaging in the dynamic range, it reduces contrast and visibly degrades the quality of composite imagery. We demonstrate how to correct linear interpolation to resolve this longstanding problem. To provide visually meaningful, high level control over the compositing process, we introduce three novel image blending operators that are designed to preserve key visual characteristics of their inputs. Our contrast preserving method applies a linear color mapping to recover the contrast lost due to linear interpolation. Our salience preserving method retains the most informative regions of the input images by balancing their relative opacity with their relative saliency. Our color preserving method extends homomorphic image processing by establishing an isomorphism between the image colors and the real numbers, allowing any mathematical operation defined on real numbers to be applied to colors without losing its algebraic properties or mapping colors out of gamut. These approaches to image blending have artistic uses in image editing and video production as well as technical applications such as image morphing and mipmapping.

Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Picture/Image Generation
Seamless Integration of Initial Sketching and Subsequent Detail Editing in Flower Modeling
Authors: Ijiri T. , Owada S. , Igarashi T.
Published: December 2006

We present an interactive modeling system for flower composition that supports seamless transformation from an initial sketch to a detailed three‐dimensional (3D) model. To begin, the user quickly sketches the overall appearance of the desired model as a collection of two‐dimensional (2D) strokes on hierarchical billboards. Then the user iteratively replaces the coarse sketch with a detailed 3D model referring to the initial sketch as a guide. Since a flower model consists of many repetitive components, the system helps the user to reuse 3D components to facilitate the modeling process. The global view of the entire model is always shown in a separate window to visualize how local modifications affect the global appearance. Our system helps the user make appropriate design decisions to keep the model consistent with the initial design, which is difficult in traditional bottom‐up plant modeling systems in which the global view only emerges after all of the details are specified.

Categories and Subject Descriptors (according to ACM CCS): I.3.6 [Computer Graphics]: Methodology and Techniques – Interaction Techniques.
Implicit Surface Modelling with a Globally Regularised Basis of Compact Support
Authors: Walder C. , Schölkopf B. , Chapelle O.
Published: December 2006

We consider the problem of constructing a globally smooth analytic function that represents a surface implicitly by way of its zero set, given sample points with surface normal vectors.

The contributions of the paper include a novel means of regularising multi‐scale compactly supported basis functions that leads to the desirable interpolation properties previously only associated with fully supported bases. We also provide a regularisation framework for simpler and more direct treatment of surface normals, along with a corresponding generalisation of the representer theorem lying at the core of kernel‐based machine learning methods.

We demonstrate the techniques on 3D problems of up to 14 million data points, as well as 4D time series data and four‐dimensional interpolation between three‐dimensional shapes.

Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Curve, surface, solid, and object representations
Efficient Large Scale Acquisition of Building Interiors
Authors: Bahmutov Gleb , Popescu Voicu , Mudure Mihai
Published: December 2006

We describe a system for the rapid acquisition of building interiors. In 40 hours, a two member team with a single acquisition device captured a model of the corridors and 20 individual rooms spanning 6 floors of a large building. Our custom acquisition device operates at interactive rates. The system provides immediate feedback to the operator. The operator guides the acquisition device in realtime and trivially avoids over sampling the planar parts of the scene such as floors, ceilings, walls, or doors. Most of the acquisition time budget is spent on the parts of the scene with complex geometry. A corridor section is modeled by acquiring a depth enhanced panorama (DEP) a teach one of its two ends and by fitting proxy geometry to the two DEPs. A room is acquired with a single DEP and proxy geometry is fitted to the planar parts. A room or a corridor section is acquired in less than 15 minutes. The acquisition device acquires high quality color intrinsically registered with the depth data. The resulting model is a texture mapped triangle mesh that supports photo realistic interactive rendering an dissuitable for applications such as virtual training and simulation.

Categories and Subject Descriptors (ACM CCS): I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling.
GEncode: Geometry‐driven compression for General Meshes
Authors: Lewiner Thomas , Craizer Marcos , Lopes Hélio , Pesco Sinésio , Velho Luiz , Medeiros Esdras
Published: December 2006

Performances of actual mesh compression algorithms vary significantly depending on the type of model it encodes. These methods rely on prior assumptions on the mesh to be efficient, such as regular connectivity, simple topology and similarity between its elements. However, these priors are implicit in usual schemes, harming their suitability for specific models. In particular, connectivity‐driven schemes are difficult to generalize to higher dimensions and to handle topological singularities. GEncode is a new single‐rate, geometry‐driven compression scheme where prior knowledge of the mesh is plugged into the coder in an explicit manner. It encodes meshes of arbitrary dimension without topological restrictions, but can incorporate topological properties, such as manifoldness, to improve the compression ratio. Prior knowledge of the geometry is taken as an input of the algorithm, represented by a function of the local geometry. This suits particularly well for scanned and remeshed models, where exact geometric priors are available. Compression results surfaces and volumes are competitive with existing schemes.
Soft Shadow Maps: Efficient Sampling of Light Source Visibility
Authors: Atty Lionel , Holzschuch Nicolas , Lapierre Marc , Hasenfratz Jean‐Marc , Hansen Charles , Sillion François X.
Published: December 2006

Shadows, particularly soft shadows, play an important role in the visual perception of a scene by providing visual cues about the shape and position of objects. Several recent algorithms produce soft shadows at interactive rates, but they do not scale well with the number of polygons in the scene or only compute the outer penumbra. In this paper, we present a new algorithm for computing interactive soft shadows on the GPU. Our new approach provides both inner‐ and outer‐penumbra for a modest computational cost, providing interactive frame‐rates for models with hundreds of thousands of polygons.

Our technique is based on a sampled image of the occluders, as in shadow map techniques. These shadow samples are used in a novel manner, computing their effect on a second projective shadow texture using fragment programs. In essence, the fraction of the light source area hidden by each sample is accumulated at each texel position of this Soft Shadow Map. We include an extensive study of the approximations caused by our algorithm, as well as its computational costs.
Compact Representation of Spectral BRDFs Using Fourier Transform and Spherical Harmonic Expansion
Authors: Xu Huiying , Sun Yinlong
Published: December 2006

This paper proposes a compact method to represent isotropic spectral BRDFs. In the first step, we perform a Fourier transform in the wavelength dimension. The resulting Fourier coefficients of the same order depend on three angles: the polar angle of the incident light, and the polar and azimuth angles of the outgoing light. In the second step, given an incident light angle, when the Fourier coefficients of the same order have an insensitive dependency on the outgoing direction, we represent these Fourier coefficients using a linear combination of spherical harmonics. Otherwise, we first decompose these Fourier coefficients into a smooth background that corresponds to diffuse component and a sharp lobe that corresponds to specular component. The smooth background is represented using a linear combination of spherical harmonics, and the sharp lobe using a Gaussian function. The representation errors are evaluated using spectral BRDFs obtained from measurement or generated from the Phong model. While maintaining sufficient accuracy, the proposed representation method has achieved data compression over a hundred of times. Examples of spectral rendering using the proposed method are also shown.
Wittgenstein's Temple: Or How Cool Is Philosophy?
Authors: McGhee Michael
Published: December 2006

How should we understand Wittgenstein's comment in 1929 that his ‘ideal’ was ‘a certain coolness’? Does it have the implication for the practice of philosophy that is suggested by the late Dewi Phillips? Wittgenstein's use of the metaphor of a temple in relation to the passions is curiously reminiscent in its structure of Rilke's first sonnet to Orpheus. In Zettel a similar preoccupation seems to be manifested in the long and unexpected passage that Wittgenstein copies out from Plato, a passage which is juxtaposed to the famous remark that the philosopher is the citizen of no community of ideas.
The interaction between across‐the‐boardwh‐movement and left‐branch extraction
Authors: Citko Barbara
Published: December 2006

Abstract. This paper explores the interaction between two independently well studiedwh‐movement strategies: across‐the‐boardwh‐movement and left‐branch extraction. Focusing on Slavic languages, which allow both ATB movement and left‐branch extraction in isolation, it shows that ATB left‐branch extraction is subject to a rather surprising restriction: the ‘‘remnants’’ inside the second conjunct must be distinct from their ‘‘correspondents’’ inside the first conjunct. The account of this restriction developed in this paper relies on the interaction of two independently motivated principles: the Linear Correspondence Axiom ofKayne 1994and a structural economy condition formulated within the framework ofChomsky's (1995)Minimalist Program.
Stock Splits: Prior and Subsequent Price Relationships
Authors: FINN FRANK J.
Published: December 2006

Although it has long been recognized that a stock split merely changes the packaging of an investor's claim to earnings, there is widespread belief in the financial community that the split confers some substantive benefits on stockholders. This paper describes an empirical investigation of the effect of split action on stock price. The split action was found to have an insignificant effect, even at a 10% level, on changes in market price over the 12 month period surrounding the split.
Accounting Information, Employees and Collective Bargaining
Authors: MAUNDERS K. T. , FOLEY B. J.
Published: December 2006

Social and political opinion in the United Kingdom has been moving in the direction of greater disclosure by companies of financial and economic information of interest to employees and trade union negotiators. This article examines the arguments which surround the issue. In particular, the role of information in the collective bargaining context is investigated in the light of a fairly simple bargaining model, The tactical and strategic impact of greater disclosure is indicated with the aid of the model. Finally the article highlights some implications for companies, trade unions and accountants.
A Note on the Nature and Determination of Income
Authors: LEE T. A.
Published: December 2006

This note comments on the doubtful application of an economic concept of personal income to the non‐personal business enterprise situation.
Forecasting the Market Return on Common Stocks
Authors: McDONALD JOHN G. , OSBORNE ALFRED E.
Published: December 2006

Most institutional fund managers attempt to adjust the stock‐bond composition of portfolios over time in anticipation of stock market movements. Using quarterly data in 1962–72 for the United States, this paper demonstrates that ‘profitable’ strategies for timing portfolio composition in common stocks and Treasury bills are generally not attainable after transaction costs if one uses lagged observations of corporate profit, money supply and consumer sentiment to forecast the market return, as this information is largely reflected in current stock prices. By contrast, accurate forecasts of these aggregate variables lead to substantial market‐timing profits relative to a buy‐and‐hold policy of remaining fully invested in common stocks.
Borrowing and Lending in a Mathematical Programming Model of Capital Budgeting
Authors: BHASKAR K. N.
Published: December 2006

Weingartner, in 1963, published his solution to the Lorie and Savage problem of choosing the optimal combination of projects given that capital rationing occurs in more than one period. This paper discusses the rationale of the Weingartner model and develops a systematic way of treating lending. Indeed not to include lending can lead to sub‐optimal results. Borrowing is then included into the model at the cost of making certain restrictive assumptions.
An Analysis of the Kuhn‐Tucker Conditions of Stochastic Programming with Reference to the Estimation of Discount Rates and Risk Premia
Authors: HAEGERT LUTZ , Adelson R. M.
Published: December 2006

The interpretation of the duality conditions of linear programming in the determination of optimal investment programmes has definitively clarified the question of the ‘correct’ discount rate in the deterministic case (Chames, Cooper, Miller, 1959). A similar total analysis of the multiple expectations case facilitates superior indications of the nature of the present value calculation for a piecemeal approach to project appraisal. A controversial issue is the question of whether the expected values of net cash flows should be discounted with a ‘risk‐adjusted’ rate or whether such flows should first be adjusted for risk and then be discounted at a ‘risk free’ rate.
Debt Management and the Use of Leasing Finance in UK Corporate Financing Strategies
Authors: FAWTHROP PROFESSOR R. A. , TERRY BRIAN
Published: December 2006

This paper reports an extensive industrial survey of UK companies' current attitudes towards debt and lease financing. It attempts to establish why and when financial managers resort to leasing and how it is incorporated into their overall debt strategy. It seeks answers to such questions as how management evaluates corporate debt capacity; what reliance they place on rules‐of‐thumb balance sheet ratios, how debt financing decisions are made, and how leasing contracts are evaluated in practice.

Ce papier est le compte‐rendu d'une étude industrielle approfondie examinant les attitudes courantes que les sociétés adoptent en matière d'endettement et de financement par leasing. Nous essayons de savoir pourquoi et quand les agents de gestion ont recours aux leasings et enfin comment ces derniers viennent s'intégrer dans la politique globale d'endettement de ces sociétés. Nous cherchons les résponses à de telles questions, à savoir: comment les agents de gestion déterminent la capacité d'endettement de leur société; quelle confiance ils accordent au rapport approximatif établi entre les éléments comparables de l'actif et du passif du bilan; comment on détermine la valeur des contrats de gérance dans la pratique.

Diese Abhandlung berichtet uber einen umfassenden industriellen Überbück von den gegenwärtigen Attituden der britischen Kapitalgesellschaften gegenüber Fremdfinanzierung und Leasing. Sie versucht festzustellen, warurn und wann die Unternehmensfinanzfachleute Gebrauch von Leasing machen und wie es in ihre Gesamtfremdfinanzierungsstrategie integriert wird. Sie sucht Antworten auf Fragen, z.B. wie das Management die Fremdfinanzierungskraft bewertet, welche Bedeutung den Bilanzfaustregelquoten angerechnet wird, wie Fremdfinanzierungsentscheidungen getroffen werden und wie Leasingverträge in der Praxis bewertet werden.
The Association of Forecast Error with Other Risk Measures
Authors: BAREFIELD RUSSELL M. , COMISKEY EUGENE E.
Published: December 2006

The forecasting errors of security analysts based on a sample of 100 New York Stock Exchange companies are developed for 1967–72. The forecast errors are related to two risk measures, (I) the coefficient of variation of earnings about linear trend and (2) the market beta. A high level of association is revealed between the ranking of companies based upon forecast error and coefficient of variation. A lower degree of association exists between forecast error and the market betas by company.

Partant d'un échantillon de 100 compagnies new yorkaises cotées à la Bourse, les analystes financiers mettent en valeur les écarts de prévision au cours de la période 1967–72. Les écarts de prévision sont liés à deux mesures de risque: (I) d'une part au coefficient de variation des bénéfices suivant une tendance linéaire, et (2) d'autre part au bêta du marchbé. On décéle une forte corrélation entre le rang des sociétès établi d'après les Ccarts de prévision et le coefficient de variation des bénéfices. II existe par contre une faible corrélation entre ces erreurs de prévision et les bêtas du marché.

Die Vorhersagefehler von Aktienanalytikern werden von einer Stichprobe von 100 an der New Yorker Börse notierten Gesellschaften für die Periode 1967–72 abgeleitet. Die Vorhersagefehler werden wiederum in Beziehung zu zwei Risikoindizien gebracht, (I) zu dem Ertragsvariationskoefiient um einen Linearen Trend und (2) zum Marktbetafaktor. Eine hohe Assoziation zwischen einer Rangordnung von Gesellschaften nach Vorhersagefehlern und Variationskoeffizienten wird gezeigt. Zwischen den Vorhersagefehlern und Marktbetafaktoren besteht eine Assoziation niedrigeren Grades.
Application of the Capital Asset Pricing Model to Multi‐period Investments
Authors: BIERMAN HAROLD , SMIDT SEYMOUR
Published: December 2006

This paper presents a method for evaluating a multi‐period asset that is consistent with the valuations implied by the capital asset pricing model, and shows how the results of the valuation processes can be expressed in terms of a number of commonly used valuation formulas.

Ce papier expose tout d'abord une méthode permettant d'estimer une valeur immobilisée à multiples périodes qui soit compatible avec les évaluations fournies par le modéle d'bvaluation de l'actif immobilisé. II montre ensuite comment les résultats des opérations d'haluation peuvent être exprimés au moyen d'un nombre de formules d'estimation couramment utilisées.

Dieser Beitrag stellt eine Methode für die Bewertung einer mehrperiodischen Investition dar, die mit den Bewertungen, die das ‘Capital Asset Pricing’ Modell impliziert, übereinstimmt. Er zeigt, wie die Ergebnisse des Bewertungsprozesses mittels einer Anzahl gebrluchlicher Formeln ausgedruckt werden konnen.
An Existence Proof for Equilibrium in a Capital Asset Market
Authors: JONES‐LEE M. W. , POSKITT D. S.
Published: December 2006

The finance literature abounds with theoretical and empirical developments of the original Sharpe/Lintner models of equilibrium in capital asset markets. Almost all of these contributions are premised upon the existence of equilibrium in such models and yet there is apparently no formal existence proof in the literature. The purpose of this paper is to establish such a proof.

La littérature de la finance abonde de développements théoriques et empiriques des premiers modèles de Sharpe/Lintner concernant l'équilibre dans les marchés des valeurs. Dans de tels modèles, la plupart de ces interventions sont basées sur l'existence d'un équilibre et pourtant il n'existe apparemment pas de preuve formelle de l'existence d'un tel équilibre dans la littérature. Le but de ce papier est donc d'en établir une telle preuve.

Das Schrifttum der Finanzwirtschaftslehre wimmelt von theoretischen und empirischen Entwicklungen der ursprünglichen Sharpe/Lintner‐Gleichgewichtsmodelle in ‘Capital Asset’ MÄrkten. Fast alle dieser Beiträge schicken das Bestehen eines Gleichgewichtes in solchen Modellen voraus obwohl anscheinend kein formeller Bestehensbeweis dafur in der Literatur zu finden ist. Der Zweck dieses Beitrages ist die Feststellung eines solchen Beweises.
The Maintenance of Financial Viability Under Inflationary Conditions: A Planning Model
Authors: COWAN PROFESSOR T. K.
Published: December 2006

The paper demonstrates how a company model may assist the forecasting of basic financial relationships under conditions of changing prices and inflation, and the examination and analysis of the effects of changes in the significant variables affecting business solvency. The paper examines the apparent inconsistency between accounting statements of profit and profitability, and the serious financial problems faced by most businesses, and it suggests a critical reappraisal of the basis of profit and profitability measurement.

Ce papier décrit comment le modèle d'une société d'une part peut s'avérer utile pour la prévision des connections financières de base dans le cas de fluctuation des prix et d'inflation, et d'autre part permet d'étudier et analyser les conséquences des changements dans les variables significatives qui agissent sur la solvabilitééconomique. Ce papier montre l'apparente incompatibilité qui existe entre les relevés comptables du profit et de la rentabilité et les graves probèmes financiers auxquels se heurtent les entreprises. Ce papier envisage enfin une réestimation critique des bases se rapportant À l'évaluation du profit et de la rentabilité.

Dieser Beitrag zeigt, wie ein Undernehmensmodell dem Vorhersagen der grundsätzlichen finanziellen Verhätnisse unter Preisänderungen und Inflation helfen kann, sowie der Untersuchung und Analyse der Auswirkung von Änderungen der Variabeln, die die Unternehmenszahlungsfähigkeit beeinflussen. Er prüft die scheinbare Unvereinbarkeit zwischen dem Bilanzgewinn und Rentabilität und den emsthaften Problemen, die die meisten Unternehmen begegnen. Es wird vorgeschlagen, dass eine weitere kritische Überprüfung der Gewinn‐ und Rentabilitätsmessungsbasis gemacht werden muss.