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Second Contribution (second + contribution)
Selected AbstractsGrammar-based Encoding of FacadesCOMPUTER GRAPHICS FORUM, Issue 4 2010Simon Haegler Abstract In this paper we propose a real-time rendering approach for procedural cities. Our first contribution is a new lightweight grammar representation that compactly encodes facade structures and allows fast per-pixel access. We call this grammar F -shade. Our second contribution is a prototype rendering system that renders an urban model from the compact representation directly on the GPU. Our suggested approach explores an interesting connection from procedural modeling to real-time rendering. Evaluating procedural descriptions at render time uses less memory than the generation of intermediate geometry. This enables us to render large urban models directly from GPU memory. [source] Dynamic Sampling and Rendering of Algebraic Point Set SurfacesCOMPUTER GRAPHICS FORUM, Issue 2 2008Gaël Guennebaud Abstract Algebraic Point Set Surfaces (APSS) define a smooth surface from a set of points using local moving least-squares (MLS) fitting of algebraic spheres. In this paper we first revisit the spherical fitting problem and provide a new, more generic solution that includes intuitive parameters for curvature control of the fitted spheres. As a second contribution we present a novel real-time rendering system of such surfaces using a dynamic up-sampling strategy combined with a conventional splatting algorithm for high quality rendering. Our approach also includes a new view dependent geometric error tailored to efficient and adaptive up-sampling of the surface. One of the key features of our system is its high degree of flexibility that enables us to achieve high performance even for highly dynamic data or complex models by exploiting temporal coherence at the primitive level. We also address the issue of efficient spatial search data structures with respect to construction, access and GPU friendliness. Finally, we present an efficient parallel GPU implementation of the algorithms and search structures. [source] An Examination of the Effects of WebTrust and Company Type on Consumers' Purchase IntentionsINTERNATIONAL JOURNAL OF AUDITING, Issue 2 2003Steven E. Kaplan This study examines the effects of both WebTrust and company type on purchasing intentions in a B2C E-commerce setting. While past studies have focused on the incremental effects of Web assurance services on Web sites, this study extends research by exploring whether WebTrust strengthens purchasing intentions for both known, and unknown, companies. Professional literature suggests that Web assurance seals such as WebTrust will primarily benefit unknown companies. A second contribution of the paper is to propose and test a model of how WebTrust and company type each lead to greater purchasing intentions. Based on a mediation model, WebTrust is expected to influence purchasing intentions through assurance beliefs. Alternatively, company type is expected to influence purchasing intentions through the formation of trusting beliefs. Under our model, because each works through a separate mediating variable, WebTrust and company type are not substitutes for each other. The results support the proposed model showing that WebTrust is mediated by assurance beliefs and company type is mediated by trusting beliefs. These results have important practical implications as they show that all companies, not just the unknown, can benefit from displaying a WebTrust seal. Thus, the results from our study suggest that the potential market for Web assurance services should include all B2C E-commerce companies. [source] A Bayesian regression approach to terrain mapping and an application to legged robot locomotionJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 10 2009Christian Plagemann We deal with the problem of learning probabilistic models of terrain surfaces from sparse and noisy elevation measurements. The key idea is to formalize this as a regression problem and to derive a solution based on nonstationary Gaussian processes. We describe how to achieve a sparse approximation of the model, which makes the model applicable to real-world data sets. The main benefits of our model are that (1) it does not require a discretization of space, (2) it also provides the uncertainty for its predictions, and (3) it adapts its covariance function to the observed data, allowing more accurate inference of terrain elevation at points that have not been observed directly. As a second contribution, we describe how a legged robot equipped with a laser range finder can utilize the developed terrain model to plan and execute a path over rough terrain. We show how a motion planner can use the learned terrain model to plan a path to a goal location, using a terrain-specific cost model to accept or reject candidate footholds. To the best of our knowledge, this was the first legged robotics system to autonomously sense, plan, and traverse a terrain surface of the given complexity. © 2009 Wiley Periodicals, Inc. [source] Reconsidering Styles of Regulatory Enforcement: Patterns in Danish Agro-Environmental InspectionLAW & POLICY, Issue 2 2000Peter May This study addresses enforcement styles of regulatory inspectors, based on an examination of the municipal enforcement of agro-environmental policies in Denmark. Our findings make three contributions to the regulatory literature. One contribution is to add empirical support for theorizing about inspectors' enforcement styles as consisting of multiple components, rather than a single continuum. We show that inspectors' enforcement styles comprise the degree of formalism and the degree of coercion that they exercise when carrying out inspections. A second contribution is in showing the relationship of different types of enforcement styles to the two underlying dimensions of the concept. A third contribution is an examination of the ways in which inspectors' enforcement styles relate to their enforcement actions. The consistency of our findings with those of other studies suggests that the dimensions and types of inspectors' enforcement styles that we observed in Denmark can be generalized to other settings. [source] A Resource-Process Framework of New Service DevelopmentPRODUCTION AND OPERATIONS MANAGEMENT, Issue 2 2007Craig M. Froehle Motivated by the increasing attention given to the operational importance of developing new services, this paper offers a theoretical framework that integrates both process- and resource-oriented perspectives of new service development (NSD) by defining and organizing 45 practice constructs for NSD-related practices and activities that occur in contemporary service firms. We employ a rigorous procedure whereby both quantitative and qualitative data were gathered through multiple rounds of interviews and card-sorting exercises with senior service managers. This iterative refinement process helps ensure that the construct domains and definitions are consistent and that they are applicable across multiple service sectors. A primary contribution of this research is to provide precise operational definitions of theoretically important NSD practice constructs. Importantly, this study expands on the NSD literature by including both resource- and process-centric perspectives within a single framework. A second contribution is to illustrate a general methodology for developing clear, concise, and consistent construct definitions that may be generally useful for production and operations management scholars interested in new construct development for emerging areas. Empirical results suggest that the resource-process framework can help guide and organize future research on, and provide insight into, a more comprehensive view of new service development. [source] X-ray diffraction by a crystal in a permanent external electric field: general considerationsACTA CRYSTALLOGRAPHICA SECTION A, Issue 4 2005Semen V. Gorfman The variations of X-ray diffraction intensities from a crystal in the presence of a permanent external electric field is modeled analytically using a first-order stationary perturbation theory. The change in a crystal, induced by an external electric field, is separated into two contributions. The first one is related to a pure polarization of an electron subsystem, while the second contribution can be reduced to the displacements of the rigid pseudoatoms from their equilibrium positions. It is shown that a change of the X-ray diffraction intensities mainly originates from the second contribution, while the influence of the pure polarization of a crystal electron subsystem is negligibly small. The quantities restored from an X-ray diffraction experiment in the presence of an external electric field were analyzed in detail in terms of a rigid pseudoatomic model of electron density and harmonic approximation for the atomic thermal motion. Explicit relationships are derived that link the properties of phonon spectra with E -field-induced variations of a structure factor, pseudoatomic displacements and piezoelectric strains. The displacements can be numerically estimated using a model of independent atomic motion if the Debye,Waller factors and pseudoatomic charges are known either from a previous single-crystal X-ray diffraction study or from density functional theory calculations. The above estimations can be used to develop an optimum strategy for a data collection that avoids the measurements of reflections insensitive to the electric-field-induced variations. [source] | ||||||||||