Interactive visualization of large digital elevation models is of continuing interest in scientific visualization, GIS, and virtual reality applications. Taking advantage of the regular structure of grid digital eleva...
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Interactive visualization of large digital elevation models is of continuing interest in scientific visualization, GIS, and virtual reality applications. Taking advantage of the regular structure of grid digital elevation models, efficient hierarchical multiresolution triangulation and adaptive level-of-detail (LOD) rendering algorithms have been developed for interactive terrain visualization. Despite the higher triangle count, these approaches generally outperform mesh simplification methods that produce irregular triangulated network (TIN) based LOD representations. In this project we combine the advantage of a TIN based mesh simplification preprocess with high-performance quadtree based LOD triangulation and rendering at run-time. This approach, called QuadTIN, generates an efficient quadtree triangulation hierarchy over any irregular point set that may originate from irregular terrain sampling or from reducing oversampling in high-resolution grid digital elevation models.
Many optimization problems on weighted graphs seek a subset of the graph's edges that has minimum weight and satisfies the problem's constraints. Two examples are the traveling salesman problem (TSP) and the d...
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Image transmission over low-bandwidth channels can be speeded up if the image coding mechanism supports regions of interest (RoIs). By such a scheme, image parts not belonging to RoIs can be encoded at a lower bitrate...
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Image transmission over low-bandwidth channels can be speeded up if the image coding mechanism supports regions of interest (RoIs). By such a scheme, image parts not belonging to RoIs can be encoded at a lower bitrate. This paper describes a flexible dynamic RoI scheme which supports the definition of arbitrarily-shaped RoIs before the start of the transmission process and the refinement of a partially transmitted image by the definition of new RoIs at any time during image transmission. The overhead to represent RoIs is kept as small as possible by exploiting a polygon-based RoI representation. Span arithmetic on a multiresolution grid is used to support the redundancy-free transmission of overlapping RoIs.
When I teach sorting algorithms in our introductory computerscience class, I always wonder how I can convince the students of the efficiency of Ο (n log n) sorts, and their complex code, vs. the ease of writing Ο (...
ISBN:
(纸本)9781581133301
When I teach sorting algorithms in our introductory computerscience class, I always wonder how I can convince the students of the efficiency of Ο (n log n) sorts, and their complex code, vs. the ease of writing Ο (n2) sorts. With today's personal computers, even bubble sorting an array of a few thousand items appears to occur instantaneously. In addition, most textbooks provide the program code for implementing most of the standard sorting algorithms, such as bubble sort, selection sort, and quick sort. Since our introductory course has a closed lab period each week, I looked for something to do with my students when it came to sorting. Making them type in the code that was in the book seemed a waste of time.
The monolithic integration of compound semiconductor devices with silicon CMOS ICs is complicated by two major factors: the large thermal expansion coefficient mismatch between silicon and other semiconductors, and th...
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ISBN:
(纸本)0780374320
The monolithic integration of compound semiconductor devices with silicon CMOS ICs is complicated by two major factors: the large thermal expansion coefficient mismatch between silicon and other semiconductors, and the large mismatch in wafer diameters between silicon and other semiconductors. Hence, most integration of compound semiconductors and silicon is done a chip at a time using long-established hybrid bump-bonding techniques. While these methods are able to begin to satisfy many immediate application needs, they do not enjoy the economic advantages of wafer-scale, batch processing found in true monolithic integration, nor to they offer the advantages of reduced parasitics, robustness of structure and density of integration that can be obtained from monolithic integration. This paper will present a philosophy for doing monolithic heterogeneous integration called the optical solder bump concept which strives to achieve all of the economic, structural and performance advantages of true monolithic integration and to do so in a modular fashion building upon commercial silicon integrated circuit processes.
This paper presents an object-oriented approach for creating multi-region non-manifold models with NURBS. The main motivation is that the geometry and shape of realistic engineering objects are intrinsically complex, ...
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This paper presents an object-oriented approach for creating multi-region non-manifold models with NURBS. The main motivation is that the geometry and shape of realistic engineering objects are intrinsically complex, usually composed by several materials and regions. Therefore, automatic and/or adaptive meshing algorithms have become revealed themselves quite useful to increase the reliability of the procedures of a FEM numerical analysis. The present approach is concerned with two aspects of 3D FEM simulation: geometric modeling, with automatic multi-region detection, and support to automatic finite element mesh generation. The final objective is to use geometric models directly in numerical applications.
Object technology is an approach that is increasingly being adopted for the development of quality software and software-intensive systems. Recent experience has demonstrated that it provides a sophisticated environme...
ISBN:
(纸本)9780769510507
Object technology is an approach that is increasingly being adopted for the development of quality software and software-intensive systems. Recent experience has demonstrated that it provides a sophisticated environment to support high quality software engineering practice. However, the use of object technology should not be restricted to languages but should encompass analysis, design, V&V and many such aspects belonging to the methodological dimension of the development life-cycle. Furthermore, it should also cover other issues belonging to the technological and contextual aspects.
professor John Belcher developed a series of short videos with animation and text of selected experiments to properly demonstrate the phenomena of electromagnetism. Such 3D animations are visually compelling, instilli...
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professor John Belcher developed a series of short videos with animation and text of selected experiments to properly demonstrate the phenomena of electromagnetism. Such 3D animations are visually compelling, instilling in the student both a sense of wonder about the phenomena and a mental model of why and how it works. The products of these approach includes video clips of demonstrations, 3D animations of these demonstration which display time changing field-lines as a guide to understanding their dynamical effects and Java applets which allow the student to actively construct and animate 2D field lines for varying configurations of sources. These technologies are also implemented to develop animations for Faraday's insights, using video clips.
Most systems that support visual interaction with 3D models use shape representations based on triangle meshes. Thesize of these representations imposes limits on applications for which complex 3D models must be acces...
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Most systems that support visual interaction with 3D models use shape representations based on triangle meshes. The
size of these representations imposes limits on applications for which complex 3D models must be accessed remotely. Techniques for
simplifying and compressing 3D models reduce the transmission time. Multiresolution formats provide quick access to a crude model
and then refine it progressively. Unfortunately, compared to the best nonprogressive compression methods, previously proposed
progressive refinement techniques impose a significant overhead when the full resolution model must be downloaded. The CPM
(Compressed Progressive Meshes) approach proposed here eliminates this overhead. It uses a new technique, which refines the
topology of the mesh in batches, which each increase the number of vertices by up to 50 percent. Less than an amortized total of 4 bits
per triangle encode where and how the topological refinements should be applied. We estimate the position of new vertices from the
positions of their topological neighbors in the less refined mesh using a new estimator that leads to representations of vertex
coordinates that are 50 percent more compact than previously reported progressive geometry compression techniques.
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