Connectivity Compression for Irregular Quadrilateral Meshes

Applications that require Internet access to remote 3D datasets are often limited by the storage costs of 3D models. Several compression methods are available to address these limits for objects represented by triangle meshes. Many CAD and VRML models, however, are represented as quadrilateral meshes or mixed triangle/quadrilateral meshes, and these models may also require compression. We present an algorithm for encoding the connectivity of such quadrilateral meshes, and we demonstrate that by preserving and exploiting the original quad structure, our approach achieves encodings 30 - 80% smaller than an approach based on randomly splitting quads into triangles. We present both a code with a proven worst-case cost of 3 bits per vertex (or 2.75 bits per vertex for meshes without valence-two vertices) and entropy-coding results for typical meshes ranging from 0.3 to 0.9 bits per vertex, depending on the regularity of the mesh. Our method may be implemented by a rule for a particular splitting of quads into triangles and by using the compression and decompression algorithms introduced in [Rossignac99] and [Rossignac&Szymczak99]. We also present extensions to the algorithm to compress meshes with holes and handles and meshes containing triangles and other polygons as well as quads

Aspects of energy requirements for rock drilling

Development of laboratory rock breakage techniques to relate energy and surface area produced by slow compression, drop hammer and stamp mill. A detailed study of laboratory rotary-percussive drilling in a wide range of rocks under different conditions, with the collection of drill cuttings and measurement of the drill parameters. The correlation of drill parameters with rock indices by energy concepts and the developed empirical formula. Field rotary-percussive drilling studies and collection of drill cuttings on the basis of laboratory analysis

The Annual Report

Transmittal Letter -- Statement of Purpose -- Board of Advisors -- Baked Alaska -- Farewell Dr. Carla Kirts -- People, activities, accomplishments -- 1992 Research Review -- Financial Statement & Funding -- Professional Staf

New proposals for the validation of trace-driven simulations

simulation;simulation models;operations research

The determination of the extent to which reading reinforced by hearing shows a gain in comprehension in comparison with reading alone when comparable materials are used.

Thesis (Ed.M.)--Boston Universit

8-Plate Multi-Resonant Coupling Using a Class-E\u3csup\u3e2\u3c/sup\u3e Power Converter For Misalignments in Capacitive Wireless Power Transfer

Misalignment is a common issue in wireless power transfer systems. It shifts the resonant frequency away from the operating frequency that affects the power flow and efficiency from the charging station to the load. This work proposes a novel capacitive wireless power transfer (CPT) using an 8-plate multi-resonant capacitive coupling to minimize the effect of misalignments. A single-active switch class-E2 power converter is utilized to achieve multi-resonance through the selection of different resonant inductors. Simulations show a widening of the resonant frequency band which offers better performance than a regular 4-plate capacitive coupling for misalignments. The hardware results of the 8-plate multi-resonant coupling show an efficiency of 88.5% for the 20.8 W test, which is 18.3% higher than that of the regular 4-plate coupling. Because of the wider resonant frequency band {455–485 kHz}, compared with the regular 4-plate coupling, the proposed design minimized the output voltage drop by 15% for a 10% misalignment. Even for large misalignments, the 8-plate performance improved by 40% compared with the 4-plate coupling