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Proceedings of the Twentieth Annual Symposium on Computational Geometry (SCG'04)

作者： Abedi, Reza Chung, Shuo-Heng Erickson, Jeff Fan, Yong Garland, Michael Guoy, Damrong Haber, Robert Sullivan, John M. Thite, Shripad Zhou, Yuan Ctr. for Proc. Simulation and Design University of Illinois Urbana-Champaign Department of Theoretical Mechanics Univ. Illinois at Urbana-Champaign Urbana IL 61801 Department of Computer Science UIUC Ctr. for Simulat. of Adv. Rockets Compl. Sci. and Engineering Program UIUC Department of Mathematics UIUC Department of Mathematics Technische Universität Berlin

We propose a new algorithm for constructing finite-element meshes suitable for spacetime discontinuous Galerkin solutions of linear hyperbolic PDEs. Given a triangular mesh of some planar domain Ω and a target time value T, our method constructs a tetrahedral mesh of the spacetime domain Ω × [0, T] in constant running time per tetrahedron in 3 using an advancing front method. Elements are added to the evolving mesh in small patches by moving a vertex of the front forward in time. Spacetime discontinuous Galerkin methods allow the numerical solution within each patch to be computed as soon as the patch is created. Our algorithm employs new mechanisms for adaptively coarsening and refining the front in response to a posteriori error estimates returned by the numerical code. A change in the front induces a corresponding refinement or coarsening of future elements in the spacetime mesh. Our algorithm adapts the duration of each element to the local quality, feature size, and degree of refinement of the underlying space mesh. We directly exploit the ability of discontinuous Galerkin methods to accommodate discontinuities in the solution fields across element boundaries.

关键词： Computer graphics

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Periodically perturbed chiral sculptured thin films

Periodically perturbed chiral sculptured thin films

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Nanomodeling

作者： Polo Jr., John A. Lakhtakia, Akhlesh Department of Physics and Technology Edinboro University of Pennsylvania Edinboro PA 16444 United States Compl. and Theor. Mat. Sci. Group Department of Engineering Science Pennsylvania State University University Park PA 16802 United States Photonics Section Department of Physics Imperial College London London SW7 2BZ United Kingdom

The piecewise homogeneity approximation is used to investigate the optical response of chiral sculptured thin films with perturbations in the angle of rise. Changes in the reflectances and transmittances of normally incident, circularly polarized light are calculated for both sinusoidal and step perturbations for a range of wavelengths, using experimentally determined material parameters. The feasibility of using a single manufacturing process to fabricate a normal dielectric mirror as well as a selective circular Bragg effect mirror is demonstrated.

关键词： Thin films

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Field test of remote control system for construction machines using robot arm

Field test of remote control system for construction machine...

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2004 IEEE International Conference on Control Applications

作者： Kawashima, K. Sasaki, T. Miyata, T. Nagai, T. Chayama, K. Fujioka, A. Mori, T. Prec. and Intelligence Laboratory Tokyo Institute of Technology Nagatsuda Midori-ku Yokohama 4259 Japan Dept. Compl. Intell. and Syst. Sci. Tokyo Institute of Technology Nagatsuda Midori-ku Yokohama 4239 Japan Dept. of Mechano-Micro Engineering Tokyo Institute of Technology Nagatsuda Midori-ku Yokohama Japan Fujita Corporation Sendagaya Sibuya-ku 4-25-2 Japan

After disasters, the remote control of construction machinery is often required to ensure the safety of workers during excavation. We have been developing a pneumatic robot arm that has 6 degrees of freedom (DOF) to realize remote control construction machines. While considering the portability issue, a lightweight fiber knitted type pneumatic artificial rubber muscle (FARM) was selected as the actuator for the arm. This arm can be installed on all construction machinery models, can be controlled remotely, and has been designed for easy installation and portability. In this research, we developed a control system to operate construction machinery remotely using the pneumatic robot arm. Then construction machinery was retrofitted with the pneumatic robot and some field tests were achieved in the real construction site. The operation time with the remote control system and with the direct operation was compared. The effectiveness of the system is confirmed from the field tests. © 2004 IEEE.

关键词： Remote control

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Osci.lation transition in decay process of overdriven detonation

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sci.nce and Technology of Energetic Materials 2004年第4期65卷 134-139页

作者： Inaba, Kazuaki Matsuo, Akiko Tanaka, Katsumi Grad. Sch. Sci. Open/Environ. Syst. Keio University Department of Mechanical Engineering Keio University 3-14-1 Hiyoshi Kohoku-ku Yokohama 223-8522 Japan Res. Inst. for Compl. Sciences Natl. Inst. Adv. Indust. Sci./T. Tsukuba 305-8568 Japan

Numerical simulations of one-dimensional and two-dimensional detonations have been performed with two-step chemical reaction mechanisms for a stoichiometric hydrogen-air mixture at initial conditions of 42.7 kPa and 293 K. One-dimensional overdriven detonations are initiated by solutions of steady ZND detonations for degree of overdrive 1.1-2.0, and by shock compression with a piston for degree of overdrive 1.2. Shock pressure histories developing from steady detonations indicate high frequency osci.lations for degree of overdrive 1.6-2.0 and low frequency osci.lations for 1.1-1.5. In the piston initiation case, post-shock pressure is temporally led in a highly overdriven condition by penetration of an interior detonation and is gradually attenuated by incident rarefaction waves. In this decaying process of the overdriven detonation, both high frequency and low frequency osci.lations are observed for the fixed degree of overdrive 1.2. The relation between the shock pressure and the osci.lation characteristics such as period and pressure amplitude agrees with results of steady detonation initiations. An initiation process of a two-dimensional detonation from high pressure and temperature conditions is also numerically investigated. Osci.lation characteristics on the center line of the cell in two-dimensional detonation indicate a similar transition to one-dimensional detonations in the decay process of initial overdriven conditions but do not depend on the shock pressure very much.

关键词： Detonation

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Application of genetic algorithm to flight schedule planning

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Systems and Computers in Japan 2004年第12期35卷 83-92页

作者： Adachi, Nobue Sato, Makihiko Kobayashi, Shigenobu Computer Systems Labs. Fujitsu Laboratories Limited Chiba 261-8588 Japan Compl. Sci. and Engineering Center Fujitsu Limited Chiba 261-8588 Japan Interdisc. Grad. Sch. Sci. and Eng. Tokyo Institute of Technology Yokohama 226-8502 Japan Information Technology Core Labs. Fujitsu Laboratories Limited Kawasaki 211-8588 Japan Department of Systems Engineering Graduate School Maebashi Institute of Technology Maebashi 371-0816 Japan

The authors developed a system that automatically creates regular aircraft flight schedules and minimizes the total number of aircraft required. Since the target problems are real-world problems having constraints that are inter-twined in a compl.x manner, the authors used a genetic algorithm to achieve the optimization. In this paper, the authors describe the problem setup and genetic algorithm configuration and verify the algorithm's effectiveness through experiments using real data. © 2004 Wiley Periodicals, Inc.

关键词： Air transportation

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Preliminary results of the united states nuclear regulatory commission's pressurized thermal shock rule reevaluation project

ASTM Special Technical Publication

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ASTM Special Technical Publication 2004年第1450期 167-182页

作者： Dickson, Terry L. Williams, Paul T. Bass, B. Richard Kirk, Mark T. Compl. Sci. and Engineering Division Oak Ridge National Laboratory Mail Stop 8056 P.O. Box 2009 Oak Ridge TN 37831-8056 United States Off. of Nuclear Regulatory Research U. States Nucl. Regulatory Commn. Mail Stop T10-E1 Washington DC 20555-0001 United States

An updated risk-informed computational methodology evolved with the help of the United States Nuclear Regulatory Commission (USNRC) PTS Rule Re-evaluation Project was discussed. The objective of the PTS Re-evaluation project was to establish a technical basis rule within the framework established by modern probabilistic risk assessment techniques and advances in technology. The updated risk-informed computational methodology was integrated into the FAVOR code that was applied to an actual PWR vessel. It was suggested that the application of the state-of-the-art technology would establish a technical basis for a potential relaxation of the current PTS regulations for commercial PWRs.

关键词： Regulatory compl.ance

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PCA based digital watermarking

PCA based digital watermarking

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7th International Conference, KES 2003

作者： Hien, Thai D. Chen, Yen-Wei Nakao, Zensho Department of EEE Faculty of Engineering Univ. of the Ryukyus Okinawa 903-0213 Japan Inst. for Compl. Sci. and Enineering Ocean Univ. of China China

ISBN: (纸本)9783540408031

This work evaluates a novel watermarking method based on Principle Component Analysis and effectiveness of the method to some watermark attacks. A PCA is used on a block by block basis to decorrelate the image pixel, watermarks are added in the Principle Components of an image. A theoretical description of the method is included together with experimental results in order to validate the methodology presented. Simulation shows the performance of the method to be robust for image cropping and some attacks such as additive noise, low pass filtering, median filtering, and jpeg compression. This research presents a new approach to watermarking fields with good performance in image cropping, and enhancement to this system with respect to robustness against various attacks is under investigation.

关键词： Digital watermarking

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Coherent Swarming from Local Interaction by Exploiting Molecular Dynamics and Stokesian Dynamics Methods

Coherent Swarming from Local Interaction by Exploiting Molec...

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2003 IEEE/RSJ International Conference on Intelligent Robots and Systems

作者： Shimizu, Masahiro Kawakatsu, Toshihiro Ishiguro, Akio Masubuchi, Yuichi Doi, Masao Dept. of Compl. Sci. and Engineering Nagoya University Furo-cho Chikusa-ku Nagoya 464-8603 Japan Dept. of Physics Tohoku University Aramaki Aoba-ku Sendai 980-8578 Japan

This paper discusses a fully decentralized algorithm able to create a coherent swarm of autonomous mobile robots from the viewpoint of "computational physics". To this end, we particularly focus on the "Molecular Dynamics method" and the "Stokesian Dynamics method", both of which are widely used to investigate multi-body systems. To verify the feasibility of our approach, this idea has been implemented to a swarm of 2-D radio-connected autonomous mobile robots as a practical example. Simulation results indicate that the proposed algorithm can control the shape of the swarm appropriately according to the current situation without losing the coherence of the swarm nor exchanging any global information among the modules. Furthermore, we have found that the local interaction which is used to exploit Stokesian Dynamics plays an essential role in order to maintain the coherence of the swarm particularly under an unstructured environment.

关键词： Mobile robots

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Image retrieval based on independent components of color histograms

Image retrieval based on independent components of color his...

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7th International Conference, KES 2003

作者： Zeng, Xiang-Yan Chen, Yen-Wei Nakao, Zensho Cheng, Jian Lu, Hanqing Department of EEE Faculty of Engineering University of the Ryukyus Okinawa 903-0213 Japan Inst. of Compl. Sci. and Engineering Ocean University of China China Natl. Lab. of Pattern Recognition Chinese Academy of Science Beijing 2772 China

ISBN: (纸本)9783540408031

Color histograms are effective for representing color visual features. However, the high dimensionality of feature vectors results in high computational cost. Several transformations, including principal component analysis (PCA), have been proposed to reduce the dimensionality. PCA reduce the dimensionality by projecting the data to a subspace which contains most of the variance. It is restricted to an orthogonal transformation and may not be the optimal to represent the intrinsic features of data. In this paper, we apply independent component analysis (ICA) to extract the features in color histograms. PCA is applied to reduce the dimensionality and then ICA is performed on the low-dimensional PCA subspace. Furthermore, spatial information is incoporated by performing ICA on a color coherent vector (CCV). The experimental results show that the proposed method outperform other methods based on SVD of quadratic matrix or PCA, in terms of retrieval accuracy.

关键词： Image retrieval

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Improvement of the noise filtering and image registration methods for PSP experiments

Improvement of the noise filtering and image registration me...

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4th ASME/JSME Joint Fluids engineering Conference

作者： Fujimatsu, Nobuyoshi Fujii, Kozo Tamura, Yoshiaki Inst. of Space/Astronautical Science 3-1-1 Yoshinodai Sagamihara Kanagawa 229-8510 Japan Dept. of Compl. Sci. and Engineering Toyo University 2100 Kujirai Kawagoeshi Saitama 350-0815 Japan

ISBN: (纸本)0791836967

Image processing procedure for noise reduction and image registration in the PSP experiments is investigated. A few kinds of filter are examined for the shot noise reduction caused by the CCD camera. The algorithm to detect a marker cell located on the model surface is proposed and an appropriate number size is shown. The algorithm using the wavelet transform is investigated to sharpen the edge around the model. The results indicate that the method developed in this paper effectively removes the shot noise and corrects the displacement of the model during wind-on.

关键词： Paint

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