bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of Individual Non‐Linear Aging Trajectories of Faces
Authors: Scherbaum K. , Sunkel M. , Seidel H.‐P. , Blanz V.
Published: October 2007

Represented in a Morphable Model, 3D faces follow curved trajectories in face space as they age. We present a novel algorithm that computes the individual aging trajectories for given faces, based on a non‐linear function that assigns an age to each face vector. This function is learned from a database of 3D scans of teenagers and adults using support vector regression.

To apply the aging prediction to images of faces, we reconstruct a 3D model from the input image, apply the aging transformation on both shape and texture, and then render the face back into the same image or into images of other individuals at the appropriate ages, for example images of older children. Among other applications, our system can help to find missing children.
Head‐eye Animation Corresponding to a Conversation for CG Characters
Authors: Masuko Soh , Hoshino Junichi
Published: October 2007

CG character animations, in which CG characters engage in conversations, are widely used in multimedia contents such as videos and games. In constructing such an animation, we should consider about many factors, such as the content of the utterance and the state of conversation, which necessitates a large amount of time and labor. To deal with this problem, this paper proposes a method, which generates the head‐eye movements of the CG characters synchronized with the conversation. In this method, so as to generate a composite head‐eye movement, the view line direction is divided into the head, eye and body rotations by sharing motion mechanism dynamically adjusted according to the view line direction. And letting the two modules generating the head and the eye movements share the same conversation state, head and eye movements synchronized with the conversation are generated. Finally, we apply the proposed method to the conversation scenes, and show that natural animation can be produced easily.
Boundary Constrained Swept Surfaces for Modelling and Animation
Authors: You L. H. , Yang X. S. , Pachulski M. , Zhang Jian J.
Published: October 2007

Due to their simplicity and intuitiveness, swept surfaces are widely used in many surface modelling applications. In this paper, we present a versatile swept surface technique called the boundary constrained swept surfaces. The most distinct feature is its ability to satisfy boundary constraints, including the shape and tangent conditions at the boundaries of a swept surface. This permits significantly varying surfaces to be both modelled and smoothly assembled, leading to the construction of complex objects. The representation, similar to an ordinary swept surface, is analytical in nature and thus it is light in storage cost and numerically very stable to compute. We also introduce a number of useful shape manipulation tools, such as sculpting forces, to deform a surface both locally and globally. In addition to being a complementary method to the mainstream surface modelling and deformation techniques, we have found it very effective in automatically rebuilding existing complex models. Model reconstruction is arguably one of the most laborious and expensive tasks in modelling complex animated characters. We demonstrate how our technique can be used to automate this process.
On‐the‐fly Curve‐skeleton Computation for 3D Shapes
Authors: Sharf Andrei , Lewiner Thomas , Shamir Ariel , Kobbelt Leif
Published: October 2007

The curve‐skeleton of a 3D object is an abstract geometrical and topological representation of its 3D shape. It maps the spatial relation of geometrically meaningful parts to a graph structure. Each arc of this graph represents a part of the object with roughly constant diameter or thickness, and approximates its centerline. This makes the curve‐skeleton suitable to describe and handle articulated objects such as characters for animation. We present an algorithm to extract such a skeleton on‐the‐fly, both from point clouds and polygonal meshes. The algorithm is based on a deformable model evolution that captures the object's volumetric shape. The deformable model involves multiple competing fronts which evolve inside the object in a coarse‐to‐fine manner. We first track these fronts' centers, and then merge and filter the resulting arcs to obtain a curve‐skeleton of the object. The process inherits the robustness of the reconstruction technique, being able to cope with noisy input, intricate geometry and complex topology. It creates a natural segmentation of the object and computes a center curve for each segment while maintaining a full correspondence between the skeleton and the boundary of the object.
Variational 3D Shape Segmentation for Bounding Volume Computation
Authors: Lu Lin , Choi Yi‐King , Wang Wenping , Kim Myung‐Soo
Published: October 2007

We propose a variational approach to computing an optimal segmentation of a 3D shape for computing a union of tight bounding volumes. Based on an affine invariant measure of e‐tightness, the resemblance to ellipsoid, a novel functional is formulated that governs an optimization process to obtain a partition with multiple components. Refinement of segmentation is driven by application‐specific error measures, so that the final bounding volume meets pre‐specified user requirement. We present examples to demonstrate the effectiveness of our method and show that it works well for computing ellipsoidal bounding volumes as well as oriented bounding boxes.
Real‐Time Simulation of Thin Shells
Authors: Choi Min Gyu , Yong Woo Seung , Ko Hyeong‐Seok
Published: October 2007

This paper proposes a real‐time simulation technique for thin shells undergoing large deformation. Shells are thin objects such as leaves and papers that can be abstracted as 2D structures. Development of a satisfactory physical model that runs in real‐time but produces visually convincing animation of thin shells has been remaining a challenge in computer graphics. Rather than resorting to shell theory which involves the most complex formulations in continuum mechanics, we adopt the energy functions from the discrete shells proposed by Grinspun et al. [GHDS03]. For real‐time integration of the governing equation, we develop a modal warping technique for shells. This new simulation framework results from making extensions to the original modal warping technique [CK05] which was developed for the simulation of 3D solids. We report experimental results, which show that the proposed method runs in real‐time even for large meshes, and that it can simulate large bending and/or twisting deformations with acceptable realism.
Geodesic‐Controlled Developable Surfaces for Modeling Paper Bending
Authors: Bo Pengbo , Wang Wenping
Published: October 2007

We present a novel and effective method for modeling a developable surface to simulate paper bending in interactive and animation applications. The method exploits the representation of a developable surface as the envelope of rectifying planes of a curve in 3D, which is therefore necessarily a geodesic on the surface. We manipulate the geodesic to provide intuitive shape control for modeling paper bending. Our method ensures a natural continuous isometric deformation from a piece of bent paper to its flat state without any stretching. Test examples show that the new scheme is fast, accurate, and easy to use, thus providing an effective approach to interactive paper bending. We also show how to handle non‐convex piecewise smooth developable surfaces.
QuadCover ‐ Surface Parameterization using Branched Coverings
Authors: Kälberer Felix , Nieser Matthias , Polthier Konrad
Published: October 2007

We introduce an algorithm for the automatic computation of global parameterizations on arbitrary simplicial 2‐manifolds, whose parameter lines are guided by a given frame field, for example, by principal curvature frames. The parameter lines are globally continuous and allow a remeshing of the surface into quadrilaterals. The algorithm converts a given frame field into a single vector field on a branched covering of the 2‐manifold and generates an integrable vector field by a Hodge decomposition on the covering space. Except for an optional smoothing and alignment of the initial frame field, the algorithm is fully automatic and generates high quality quadrilateral meshes.
Mesh Segmentation via Spectral Embedding and Contour Analysis
Authors: Liu Rong , Zhang Hao
Published: October 2007

We propose a mesh segmentation algorithm via recursive bisection where at each step, a sub‐mesh embedded in 3D is first spectrally projected into the plane and then a contour is extracted from the planar embedding. We rely on two operators to compute the projection: the well‐known graph Laplacian and a geometric operator designed to emphasize concavity. The two embeddings reveal distinctive shape semantics of the 3D model and complement each other in capturing the structural or geometrical aspect of a segmentation. Transforming the shape analysis problem to the 2D domain also facilitates our segmentability analysis and sampling tasks. We propose a novel measure of the segmentability of a shape, which is used as the stopping criterionfor our segmentation. The measure is derived from simple area‐ and perimeter‐based convexity measures. We achieve invariance to shape bending through multi‐dimensional scaling (MDS) based on the notion of inner distance. We also utilize inner distances to develop a novel sampling scheme to extract two samples along a contour which correspond to two vertices residing on different parts of the sub‐mesh. The two samples are used to derive a spectral linear ordering of the mesh faces. We obtain a final cut via a linear search over the face sequence based on part salience, where a choice of weights for different factors of part salience is guided by the result from segmentability analysis.
Highly Parallel Fast KD‐tree Construction for Interactive Ray Tracing of Dynamic Scenes
Authors: Shevtsov Maxim , Soupikov Alexei , Kapustin Alexander
Published: October 2007

We present a highly parallel, linearly scalable technique of kd‐tree construction for ray tracing of dynamic geometry. We use conventional kd‐tree compatible with the high performing algorithms such as MLRTA or frustum tracing. Proposed technique offers exceptional construction speed maintaining reasonable kd‐tree quality for rendering stage. The algorithm builds a kd‐tree from scratch each frame, thus prior knowledge of motion /deformation or motion constraints are not required. We achieve nearly real‐time performance of 7‐12 FPS for models with 200K of dynamic triangles at 1024x1024 resolution with shadows and textures.
Stackless KD‐Tree Traversal for High Performance GPU Ray Tracing
Authors: Popov Stefan , Günther Johannes , Seidel Hans‐Peter , Slusallek Philipp
Published: October 2007

Significant advances have been achieved for realtime ray tracing recently, but realtime performance for complex scenes still requires large computational resources not yet available from the CPUs in standard PCs. Incidentally, most of these PCs also contain modern GPUs that do offer much larger raw compute power. However, limitations in the programming and memory model have so far kept the performance of GPU ray tracers well below that of their CPU counterparts.

In this paper we present a novel packet ray traversal implementation that completely eliminates the need for maintaining a stack during kd‐tree traversal and that reduces the number of traversal steps per ray. While CPUs benefit moderately from the stackless approach, it improves GPU performance significantly. We achieve a peak performance of over 16 million rays per second for reasonably complex scenes, including complex shading and secondary rays. Several examples show that with this new technique GPUs can actually outperform equivalent CPU based ray tracers.
A Bidirectional Light Field ‐ Hologram Transform
Authors: Ziegler Remo , Bucheli Simon , Ahrenberg Lukas , Magnor Marcus , Gross Markus
Published: October 2007

In this paper, we propose a novel framework to represent visual information. Extending the notion of conventional image‐based rendering, our framework makes joint use of both light fields and holograms as complementary representations. We demonstrate how light fields can be transformed into holograms, and vice versa. By exploiting the advantages of either representation, our proposed dual representation and processing pipeline is able to overcome the limitations inherent to light fields and holograms alone. We show various examples from synthetic and real light fields to digital holograms demonstrating advantages of either representation, such as speckle‐free images, ghosting‐free images, aliasing‐free recording, natural light recording, aperture‐dependent effects and real‐time rendering which can all be achieved using the same framework. Capturing holograms under white light illumination is one promising application for future work.
Markerless 4 gestures 6 DOF real‐time visual tracking of the human hand with automatic initialization
Authors: Schlattmann Markus , Kahlesz Ferenc , Sarlette Ralf , Klein Reinhard
Published: October 2007

In this paper we present a novel computer vision based hand‐tracking technique, which is capable of robustly tracking 6+4DOF of the human hand in real‐time (at least 25 frames per second) with the help of 3 (or more) off‐the‐shelf consumer cameras. ‘6+4DOF’ means that the system can track the global pose (6 continuous parameters for translation and rotation) of 4 different gestures. A key feature of our system is its fully automatic real‐time initialization procedure, which, along with a sound tracking‐lost detector, makes the system fit for real‐world applications. Because of this, our method acts as an enabling technology for uncumbersome hand‐based 3D Human‐Computer‐Interaction (HCI). Previously, using the hand as an at least 6DOF input device involved the use of either datagloves or markers. Using our tracking we evaluated the use of the hand as an input device for two prevalent Virtual Reality applications: fly‐through exploration of a virtual world and a simple digital assembly simulation.
Efficient Reflectance and Visibility Approximations for Environment Map Rendering
Authors: Green Paul , Kautz Jan , Durand Frédo
Published: October 2007

We present a technique for approximating isotropic BRDFs and precomputed self‐occlusion that enables accurate and efficient prefiltered environment map rendering. Our approach uses a nonlinear approximation of the BRDF as a weighted sum of isotropic Gaussian functions. Our representation requires a minimal amount of storage, can accurately represent BRDFs of arbitrary sharpness, and is above all, efficient to render. We precompute visibility due to self‐occlusion and store a low‐frequency approximation suitable for glossy reflections. We demonstrate our method by fitting our representation to measured BRDF data, yielding high visual quality at real‐time frame rates.
High‐Quality Adaptive Soft Shadow Mapping
Authors: Guennebaud Gaël , Barthe Loïc , Paulin Mathias
Published: October 2007

The recent soft shadow mapping technique [GBP06] allows the rendering in real‐time of convincing soft shadows on complex and dynamic scenes using a single shadow map. While attractive, this method suffers from shadow overestimation and becomes both expensive and approximate when dealing with large penumbrae. This paper proposes new solutions removing these limitations and hence providing an efficient and practical technique for soft shadow generation. First, we propose a new visibility computation procedure based on the detection of occluder contours, that is more accurate and faster while reducing aliasing. Secondly, we present a shadow map multi‐resolution strategy keeping the computation complexity almost independent on the light size while maintaining high‐quality rendering. Finally, we propose a view‐dependent adaptive strategy, that automatically reduces the screen resolution in the region of large penumbrae, thus allowing us to keep very high frame rates in any situation.
Visibility Sampling on GPU and Applications
Authors: Eisemann Elmar , Décoret Xavier
Published: October 2007

In this paper, we show how recent GPUs can be used to very efficiently and conveniently sample the visibility between two surfaces, given a set of occluding triangles. We use bitwise arithmetics to evaluate, encode, and combine the samples blocked by each triangle. In particular, the number of operations is almost independent of the number of samples. Our method requires no CPU/GPU transfers, is fully implemented as geometric, vertex and fragment shaders, and thus does not impose to modify the way the geometry is sent to the graphics card. We finally present applications to soft shadows, and visibility analysis for level design.
Real‐time homogenous translucent material editing
Authors: Xu Kun , Gao Yue , Li Yong , Ju Tao , Hu Shi‐Min
Published: October 2007

This paper presents a novel method for real‐time homogenous translucent material editing under fixed illumination. We consider the complete analytic BSSRDF model proposed by Jensen et al. [JMLH01], including both multiple scattering and single scattering. Our method allows the user to adjust the analytic parameters of BSSRDF and provides high‐quality, real‐time rendering feedback. Inspired by recently developed Precomputed Radiance Transfer (PRT) techniques, we approximate both the multiple scattering diffuse reflectance function and the single scattering exponential attenuation function in the analytic model using basis functions, so that re‐computing the outgoing radiance at each vertex as parameters change reduces to simple dot products. In addition, using a non‐uniform piecewise polynomial basis, we are able to achieve smaller approximation error than using bases adopted in previous PRT‐based works, such as spherical harmonics and wavelets. Using hardware acceleration, we demonstrate that our system generates images comparable to [JMLH01]at real‐time frame‐rates.
Defocus Magnification
Authors: Bae Soonmin , Durand Frédo
Published: October 2007

A blurry background due to shallow depth of field is often desired for photographs such as portraits, but, unfortunately, small point‐and‐shoot cameras do not permit enough defocus because of the small diameter of their lenses. We present an image‐processing technique that increases the defocus in an image to simulate the shallow depth of field of a lens with a larger aperture.

Our technique estimates the spatially‐varying amount of blur over the image, and then uses a simple image‐based technique to increase defocus. We first estimate the size of the blur kernel at edges and then propagate this defocus measure over the image. Using our defocus map, we magnify the existing blurriness, which means that we blur blurry regions and keep sharp regions sharp. In contrast to more difficult problems such as depth from defocus, we do not require precise depth estimation and do not need to disambiguate textureless regions.
Contrast Restoration by Adaptive Countershading
Authors: Krawczyk Grzegorz , Myszkowski Karol , Seidel Hans‐Peter
Published: October 2007

The ABSTRACT is to be in fully‐justified italicized text, between two horizontal lines, in one‐column format, below the author and affiliation information. Use the word “Abstract” as the title, in 9‐point Times, boldface type, left‐aligned to the text, initially capitalized. The abstract is to be in 9‐point, single‐spaced type. The abstract may be up to 3 inches (7.62 cm) long. Leave one blank line after the abstract, then add the subject categories according to the ACM Classification Index (see http://www.acm.org/class/1998/).
Synthetic Shutter Speed Imaging
Authors: Telleen J. , Sullivan A. , Yee J. , Wang O. , Gunawardane P. , Collins I. , Davis J.
Published: October 2007

Hand held long exposures often result in blurred photographs due to camera shake. Long exposures are desirable both for artistic effect and in low‐light situations. We propose a novel method for digitally reducing imaging artifacts, which does not require additional hardware such as tripods or optical image stabilization lenses. A series of photographs is acquired with short shutter times, stabilized using image alignment, and then composited. Our method is capable of reducing noise and blurring due to camera shake, while simultaneously preserving the desirable effects of motion blur. The resulting images are very similar to those obtained using a tripod and a true extended exposure.
Diorama Construction From a Single Image
Authors: Assa J. , Wolf L.
Published: October 2007

Diorama artists produce a spectacular 3D effect in a confined space by generating depth illusions that are faithful to the ordering of the objects in a large real or imaginary scene. Indeed, cognitive scientists have discovered that depth perception is mostly affected by depth order and precedence among objects. Motivated by these findings, we employ ordinal cues to construct a model from a single image that similarly to Dioramas, intensifies the depth perception. We demonstrate that such models are sufficient for the creation of realistic 3D visual experiences.

The initial step of our technique extracts several relative depth cues that are well known to exist in the human visual system. Next, we integrate the resulting cues to create a coherent surface. We introduce wide slits in the surface, thus generalizing the concept of cardboard cutout layers. Lastly, the surface geometry and texture are extended alongside the slits, to allow small changes in the viewpoint which enriches the depth illusion.
A Generic Pigment Model for Digital Painting
Authors: Xu Songhua , Tan Haisheng , Jiao Xiantao , Lau Francis C.M. , Pan Yunhe
Published: October 2007

We propose a generic pigment model suitable for digital painting in a wide range of genres including traditional Chinese painting and water‐based painting. The model embodies a simulation of the pigment‐water solution and its interaction with the brush and the paper at the level of pigment particles; such a level of detail is needed for achieving highly intricate effects by the artist. The simulation covers pigment diffusion and sorption processes at the paper surface, and aspects of pigment particle deposition on the paper. We follow rules and formulations from quantitative studies of adsorption and diffusion processes in surface chemistry and the textile industry. The result is a pigment model that spans a continuum from the very wet to the very dry brush stroke effects. We also propose a new pigment mixing method based on machine learning techniques to emulate pigment mixing in real life as well as to support the creation of new artificial pigments. To experiment with the proposed model, we embedded the model in a sophisticated digital brush system. The combined system exhibits interactive speed on a modest PC platform. http://www.cs.hku.hk/~songhua/pigment provides supplementary materials for this paper.
Image Dequantization: Restoration of Quantized Colors
Authors: Kim Tae‐hoon , Ahn Jongwoo , Choi Min Gyu
Published: October 2007

Color quantization replaces the color of each pixel with the closest representative color, and thus it makes the resulting image partitioned into uniformly‐colored regions. As a consequence, continuous, detailed variations of color over the corresponding regions in the original image are lost through color quantization. In this paper, we present a novel blind scheme for restoring such variations from a color‐quantized input image without a priori knowledge of the quantization method. Our scheme identifies which pairs of uniformly‐colored regions in the input image should have continuous variations of color in the resulting image. Then, such regions are seamlessly stitched through optimization while preserving the closest representative colors. The user can optionally indicate which regions should be separated or stitched by scribbling constraint brushes across the regions. We demonstrate the effectiveness of our approach through diverse examples, such as photographs, cartoons, and artistic illustrations.
Texturing Internal Surfaces from a Few Cross Sections
Authors: Pietroni Nico , Otaduy Miguel A. , Bickel Bernd , Ganovelli Fabio , Gross Markus
Published: October 2007

We introduce a new appearance‐modeling paradigm for synthesizing the internal structure of a 3D model from photographs of a few cross‐sections of a real object. When the internal surfaces of the 3D model are revealed as it is cut, carved, or simply clipped, we synthesize their texture from the input photographs. Our texture synthesis algorithm is best classified as a morphing technique, which efficiently outputs the texture attributes of each surface point on demand. For determining source points and their weights in the morphing algorithm, we propose an interpolation domain based on BSP trees that naturally resembles planar splitting of real objects. In the context of the interpolation domain, we define efficient warping and morphing operations that allow for real‐time synthesis of textures. Overall, our modeling paradigm, together with its realization through our texture morphing algorithm, allow users to author 3D models that reveal highly realistic internal surfaces in a variety of artistic flavors.
Depth‐of‐Field Rendering by Pyramidal Image Processing
Authors: Kraus M. , Strengert M.
Published: October 2007

We present an image‐based algorithm for interactive rendering depth‐of‐field effects in images with depth maps. While previously published methods for interactive depth‐of‐field rendering suffer from various rendering artifacts such as color bleeding and sharpened or darkened silhouettes, our algorithm achieves a significantly improved image quality by employing recently proposed GPU‐based pyramid methods for image blurring and pixel disocclusion. Due to the same reason, our algorithm offers an interactive rendering performance on modern GPUs and is suitable for real‐time rendering for small circles of confusion. We validate the image quality provided by our algorithm by side‐by‐side comparisons with results obtained by distributed ray tracing.
Crowds by Example
Authors: Lerner Alon , Chrysanthou Yiorgos , Lischinski Dani
Published: October 2007

We present an example‐based crowd simulation technique. Most crowd simulation techniques assume that the behavior exhibited by each person in the crowd can be defined by a restricted set of rules. This assumption limits the behavioral complexity of the simulated agents. By learning from real‐world examples, our autonomous agents display complex natural behaviors that are often missing in crowd simulations. Examples are created from tracked video segments of real pedestrian crowds. During a simulation, autonomous agents search for examples that closely match the situation that they are facing. Trajectories taken by real people in similar situations, are copied to the simulated agents, resulting in seemingly natural behaviors.
Layered Performance Animation with Correlation Maps
Authors: Neff Michael , Albrecht Irene , Seidel Hans‐Peter
Published: October 2007

Performance has a spontaneity and “aliveness” that can be difficult to capture in more methodical animation processes such as keyframing. Access to performance animation has traditionally been limited to either low degree of freedom characters or required expensive hardware. We present a performance‐based animation system for humanoid characters that requires no special hardware, relying only on mouse and keyboard input. We deal with the problem of controlling such a high degree of freedom model with low degree of freedom input through the use of correlation maps which employ 2D mouse input to modify a set of expressively relevant character parameters. Control can be continuously varied by rapidly switching between these maps. We present flexible techniques for varying and combining these maps and a simple process for defining them. The tool is highly configurable, presenting suitable defaults for novices and supporting a high degree of customization and control for experts. Animation can be recorded on a single pass, or multiple layers can be used to increase detail. Results from a user study indicate that novices are able to produce reasonable animations within their first hour of using the system. We also show more complicated results for walking and a standing character that gestures and dances.
Interactive Visual Workspaces with Dynamic Foveal Areas and Adaptive Composite Interfaces
Authors: Cotting Daniel , Gross Markus
Published: October 2007

This paper presents novel techniques and metaphors for on‐demand visual workspaces in everyday office environments, providing space‐efficient, flexible and highly interactive graphical user interfaces using projected displays. For increased resolution, contents personalization and interactive visualization, the users can augment the large‐scale projections with dynamic high‐resolution foveal enhancements using a pocket light metaphor. To further optimize the presentation at a given resolution, the design of the displays can be modified interactively, and like a jigsaw puzzle, the layout can be customized using an adaptive compositing approach which supports free‐form focus‐and‐context rendering. With a unified intensity‐based tracking approach, we allow for natural multi‐touch interaction with the information space through bare hands, pointers and pens on arbitrary surfaces.
Consistent Viewing and Interaction for Multiple Users in Projection‐Based VR Systems
Authors: De Haan Gerwin , Molenaar René , Koutek Michal , Post Frits H.
Published: October 2007

In projection‐based Virtual Reality (VR) systems, typically only one headtracked user views stereo images rendered from the correct view position. For other users, who are presented a distorted image, moving with the first user's head motion, it is difficult to correctly view and interact with 3D objects in the virtual environment. In close‐range VR systems, such as the Virtual Workbench, distortion effects are especially large because objects are within close range and users are relatively far apart. On these systems, multi‐user collaboration proves to be difficult. In this paper, we analyze the problem and describe a novel, easy to implement method to prevent and reduce image distortion and its negative effects on close‐range interaction task performance. First, our method combines a shared camera model and view distortion compensation. It minimizes the overall distortion for each user, while important user‐personal objects such as interaction cursors, rays and controls remain distortion‐free. Second, our method retains co‐location for interaction techniques to make interaction more consistent. We performed a user experiment on our Virtual Workbench to analyze user performance under distorted view conditions with and without the use of our method. Our findings demonstrate the negative impact of view distortion on task performance and the positive effect our method introduces. This indicates that our method can enhance the multi‐user collaboration experience on close‐range, projection‐based VR systems.
Shape‐aware Volume Illustration
Authors: Chen Wei , Lu Aidong , Ebert David S.
Published: October 2007

We introduce a novel volume illustration technique for regularly sampled volume datasets. The fundamental difference between previous volume illustration algorithms and ours is that our results are shape‐aware, as they depend not only on the rendering styles, but also the shape styles. We propose a new data structure that is derived from the input volume and consists of a distance volume and a segmentation volume. The distance volume is used to reconstruct a continuous field around the object boundary, facilitating smooth illustrations of boundaries and silhouettes. The segmentation volume allows us to abstract or remove distracting details and noise, and apply different rendering styles to different objects and components. We also demonstrate how to modify the shape of illustrated objects using a new 2D curve analogy technique. This provides an interactive method for learning shape variations from 2D hand‐painted illustrations by drawing several lines. Our experiments on several volume datasets demonstrate that the proposed approach can achieve visually appealing and shape‐aware illustrations. The feedback from medical illustrators is quite encouraging.
Style Transfer Functions for Illustrative Volume Rendering
Authors: Bruckner S. , Gröller M. E.
Published: October 2007

Illustrative volume visualization frequently employs non‐photorealistic rendering techniques to enhance important features or to suppress unwanted details. However, it is difficult to integrate multiple non‐photorealistic rendering approaches into a single framework due to great differences in the individual methods and their parameters. In this paper, we present the concept of style transfer functions. Our approach enables flexible data‐driven illumination which goes beyond using the transfer function to just assign colors and opacities. An image‐based lighting model uses sphere maps to represent non‐photorealistic rendering styles. Style transfer functions allow us to combine a multitude of different shading styles in a single rendering. We extend this concept with a technique for curvature‐controlled style contours and an illustrative transparency model. Our implementation of the presented methods allows interactive generation of high‐quality volumetric illustrations.
PUBLIC PROCUREMENT, PUBLIC VALUE AND THE NORTHERN IRELAND UNEMPLOYMENT PILOT PROJECT
Authors: ERRIDGE ANDREW
Published: October 2007

This paper analyses the regulatory, commercial and socio‐economic goals underlying UK public procurement policy, highlighting the conflicts inherent between them and arguing that there is an overemphasis on commercial goals. A critique of the market model leads to consideration of the utility of the ‘public value’ concept as a means of assessing the achievement of public procurement goals in a balanced way through a greater emphasis on public consultation and the impacts and outcomes of procurement. An analytical framework is proposed, based on public value, against which to assess the delivery of public procurement policies. The framework is used to analyse a pilot project conducted in Northern Ireland on increasing employment through public service and construction projects. The paper demonstrates the achievement of a range of procurement goals and values and concludes by calling both for further research into the validity of the concept of public value and more extensive application of the framework.
A SCIENTIFIC STANDARD AND AN AGENCY’S LEGAL INDEPENDENCE: WHICH OF THESE REPUTATION PROTECTION MECHANISMS IS LESS SUSCEPTIBLE TO POLITICAL MOVES?
Authors: MAOR MOSHE
Published: October 2007

This article presents a model that introduces a scientific ‘gold’ standard as a reputation protection mechanism operating alongside an agency’s legal independence. It tries to gauge which of the two is less susceptible to political moves. The model suggests that the scientific ‘gold’ standard for agency decisions is less susceptible to political moves because of its important role as a legitimating device for both government ministers and regulators. Government ministers are able to address multiple audiences and even to respond to aggressive strategies by powerful interest groups by undermining one reputation protection mechanism (that is, an agency’s independence) without weakening the other (that is, the scientific barrier for granting full‐subsidy status to treatments that lack comparative therapeutic advantage). This implies that drug reimbursement mechanisms that provide a high quality of drug evaluation are designed to be effective.
THE CONDITIONS FOR HEALTH AND SOCIAL CARE POLICY: ROUTINES AND INSTITUTIONS IN THE DUTCH CASE OF NEED ASSESSMENT
Authors: VAN RAAK ARNO , PAULUS AGGIE , VAN DER MADE JAN
Published: October 2007

By focusing on institutions (rules for action) and routines (patterned behaviour) our intention is to contribute to the understanding of government policy and its outcomes in health and social care. We analysed data to show how the relationship between a new idea for a routine and new rules from the government on the one hand, and existing rules and routines in society on the other, as well as the interaction between rule makers and rule takers (i.e. those who are governed by those rules), have an impact on the change or maintenance of routines. The data concern the case of government policy for need assessment (that is, assessment of needs) in The Netherlands.

As our discussion will show, even a national government, however, is not able to completely impose its will on other agents in order to change existing routines. The concept of ‘negotiated order’ helps us to understand why. In the case reported here, the Dutch government and the home care agencies had to exercise give and take, the outcome being a suboptimal result for both.
THE IMPACT OF PUBLIC SERVICE MOTIVES ON WORK OUTCOMES IN AUSTRALIA: A COMPARATIVE MULTI‐DIMENSIONAL ANALYSIS
Authors: TAYLOR JEANNETTE
Published: October 2007

There is a general consensus that individuals who are driven to serve the public interest can possess a mix of public service motives for engaging in altruistic actions. This article proposes that when analysed simultaneously, some public service motives may play a more important role than others in influencing work outcomes. The pressing questions are which ones and how? Through a survey of a group of Australian public sector employees, this article explores the relationship between the various dimensions of public service motivation (PSM) and the common work outcomes: organizational commitment, job satisfaction and job motivation. The combinations of PSM dimensions that had a greater impact on these work outcomes are also found to vary with different outcomes.
PATH DEPENDENCY AND INSTITUTIONAL CHANGE: THE CASE OF INDUSTRIAL EMISSION CONTROL IN SWEDEN
Authors: DUIT ANDREAS
Published: October 2007

Theory‐independent measures of institutional change can be developed by identifying and tracking changes in institutional reproduction mechanisms. Such measures can then be used to assess the empirical validity of theoretical models of institutional change. This article performs an analysis of reproduction mechanisms in a case study of a Swedish institution for emission control during the period 1960–2000. The analysis reveals the existence of a highly path dependent institutional development, powerful enough to withstand a wide‐ranging institutional reform implemented in the late 1990s. The case study supports a gradualist model over a punctuated equilibrium model of institutional change, but the analysis also demonstrates the need for path dependency theory to pay greater attention to the question of how micro‐level institutional interaction generates aggregate patterns of change and stability.
Operational Risk: A Survey
Authors: Moosa Imad A.
Published: October 2007

Operational risk has, in a relatively short period of time, risen from non‐recognition to prominence as the culprit for spectacular corporate collapses. This paper surveys the mushrooming literature on the subject, covering the definition, classification, characteristics, modeling and management of operational risk. It is concluded that operational risk is a controversial topic that will generate a significant amount of research in the years to come.
Sub‐Optimality of Income Statement‐Based Methods for Measuring Operational Risk under Basel II: Empirical Evidence from Spanish Banks
Authors: Bonsón Enrique , Escobar Tomás , Flores Francisco
Published: October 2007

The New Basel Capital Accord (Basel II) was created with the intention of establishing a framework in which financial entities can manage their risks in a more detailed and efficient way. Within this general reform movement, Operational Risk emerges as a fundamental variable. OR can be managed by three alternative methods: the Basic Indicator Approach, Standard Approach and Advanced Measurement Approach. The choice of which method to adopt has become of supreme interest for senior banking managers. This study analyzes the exactitude of the underlying implicit hypotheses that support each method, distinguishing between income statement based methods and the management accounting based method. In the present study the non‐optimum character of the two Income Statement‐based methods is empirically confirmed, in the light of the data provided by Spanish financial entities.
MIGRATIONS OF HISTORICAL MANUSCRIPTS
Authors: Craster H. H. E.
Published: October 2007

These notes ignore the migrations of MS. collections which are recorded by the Hist. MSS. Commission.
LXXX1X.—The theories of Cardinal Pierre D'Ailfy concerning forms of government in church and state, with special reference to his interest in suggestions made by William of Occam
Authors: Roberts Agnes E.
Published: October 2007

LXXXIX.—The theories of Cardinal Pierre D'Ailly concerning forms of government in church and state, with special reference to his interest in suggestions made by William of Occam. By Agnes E. Roberts, M.A.
Conquest, Colonization and the Church: Ecclesiastical Organization in the Danelaw
Authors: Hadley Dawn M.
Published: October 2007

This article reconsiders the fate of the Church in the Danelaw in the period following the Viking invasions and settlement of the region. It is generally accepted that the peculiarities of ecclesiastical organization found in the Danelaw can be attributed to the impact of the Vikings, but although they undoubtedly inflicted terrible damage on the Church there may be other explanations for the idiosyncracies of the region. Pre-existing regional differences and the impact of the West Saxon conquest of the region must also be considered. The existing model for the development of the parochial system in Anglo-Saxon England-the so-called ‘minster model’-increases the sense that the Danelaw had experienced a great calamity. Yet this model is open to criticism, and its applicability to the Danelaw is brought into question. Elements of continuity can be identified as can evidence for change, and this article concludes that the period of Scandinavian settlement was but one factor that shaped ecclesiastical organization in the later Anglo-Saxon centuries.
Christopher Atkinson and the Victualling Board, 1775–82
Authors: Syrett David
Published: October 2007

This article is a study of a grain merchant in the City of London and corrupt contracting with the Victualling Board during the American War, 1775–82.
The Rise of Ethical Anarchism in Britain, 1885–1900
Authors: Bevir Mark
Published: October 2007

In the nineteenth century, anarchists were strict individualists favouring clandestine organization and violent revolution: in the twentieth century, they have been romantic communalists favouring moral experiments and sexual liberation. This article examines the growth of this ethical anarchism in Britain in the late nineteenth century, as exemplified by the Freedom Group and the Tolstoyans. These anarchists adopted the moral and even religious concerns of groups such as the Fellowship of the New Life. Their anarchist theory resembled the beliefs of counter-cultural groups such as the aesthetes more closely than it did earlier forms of anarchism. And this theory led them into the movements for sex reform and communal living.
The Institute of Historical Research, 1971–96: its Third Quarter-century
Authors: Smith Steven R. B.
Published: October 2007

The Institute of Historical Research is the national centre for historical research, as well as being an international meeting place for historians, and it will be celebrating its seventy-fifth anniversary in July 1996. This article is an outline of its developments over the last quarter of a century, including statistical data on seminars, training courses, income and membership, along with information on the Institute's library, research projects, publications and role as an information centre.
Saint Anselm and his Father, Gundulf
Authors: Robson Michael
Published: October 2007

Saint Anselm quarrelled with his father, Gundulf, left home and settled at Bec. There is a negative account of Gundulf in Eadmer's biography, although there is a reference to his taking the monastic habit near the end of his life. A necrology of Christ Church cathedral priory at Canterbury in two late manuscripts contains a hitherto unnoticed entry for Anselm's parents. This discovery, which is not mentioned in R. W. Southern's two major studies of Anselm, is of particular relevance for the saint's later dealings with his father. It leaves open the question of a subsequent reconconliation, despite the assumptions of medieval hagiography.
The Hundred Rolls of 1255
Authors: Roffe David
Published: October 2007

Although less ambitious than the inquests of 1274 and 1279, the Hundred Rolls survey of 1255 was probably the first comprehensive audit of regalities in the localities. Its context was the grave financial embarrassment of the Crown in the early twelve-fifties, and the findings were almost certainly used to reassess increments on shire farms which reached a record high in 1256/7. Subsequently, the rolls were not as influential as the records of Edward I's inquests, for the policy that brought them into being led directly to the baronial plan of reform of 1258. However, their concerns are echoed in the later Hundred Rolls, and it seems clear that they informed the period of inquiry and legislation of the twelve-seventies and eighties. The articles of the inquiry have been reconstructed from the surviving returns and are here appended.
The Origins of the Nottinghamshire Whigs: an Analysis of the Subscribers to the Election Expenses of Sir Scrope Howe and John White
Authors: Seddon P. R.
Published: October 2007

An investigation of the support for Sir Scrope Howe and John White at the Nottinghamshire election of I September 1679 from an analysis of subscribers to their election expenses. A foremost proponent of Exclusion, William Sacheverell, and men who were to sustain the Whig cause in Nottinghamshire were the principal subscribers. Numerically a minority, dissenters led by patrons of Presbyterianism and Independency with three Anglican incumbents subscribed. Contributions from lesser freeholders and townsmen of Nottingham indicate ‘popular’ support. Though subscriptions from the aristocracy, the majority of the shire's and Nottingham office-holders are absent, from diverse sources a campaign to defeat their lieutenant's nominee was funded.
The Rise and Fall of a Noble Dynasty: Henry VII and the Lords Willoughby de Broke
Authors: Luckett D. A.
Published: October 2007

A study of the first two lords Willoughby de Broke. The career of Robert, the first baron, is traced from his service under Edward IV, through rebellion against Richard III and subsequent exile. His part in the Bosworth campaign of 1485 and the rewards he subsequently received from Henry VII are examined, as is his later career as a leading Crown agent in Wiltshire, Devon and Cornwall. The article then looks at how the family fared after Robert's death in 1502. The most striking aspect of this is the way in which Henry VII attempted to undermine the power of Robert's son and heir through harsh fines and other (apparently unjustified) impositions. In doing so, the article concludes, Henry was betraying his growing feelings of political insecurity by striking against an apparently innocent young man.
Sir William Herbert's Acquisition of Offices in Wales on the Death of Henry, Earl of Worcester in 1549
Authors: ROBINSON W. R. B.
Published: October 2007

The article discusses the series of royal grants which marked the rapid rise of William Herbert in the years before his creation as earl of Pembroke in 1551, and particularly a hitherto unnoticed grant of 14 December 1549 (summarized) of most of the offices in south and central Wales previously held by Henry Somerset (d. 1549), earl of Worcester. Using mainly Public Record Office sources, it underlines the importance of this grant in establishing Herbert's predominance in Wales and describes how the loss of these offices by the Somerset family exacerbated its financial embarrassment in the mid sixteenth century.