• Title/Summary/Keyword: vector fields

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Space Deformation of Parametric Surface Based on Extension Function

  • Wang, Xiaoping;Ye, Zhenglin;Meng, Yaqin;Li, Hongda
    • International Journal of CAD/CAM
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    • v.1 no.1
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    • pp.23-32
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    • 2002
  • In this paper, a new technique of space deformation for parametric surfaces with so-called extension function (EF) is presented. Firstly, a special extension function is introduced. Then an operator matrix is constructed on the basis of EF. Finally the deformation of a surface is achieved through multiplying the equation of the surface by an operator matrix or adding the multiplication of some vector and the operator matrix to the equation. Interactively modifying control parameters, ideal deformation effect can be got. The implementation shows that the method is simple, intuitive and easy to control. It can be used in such fields as geometric modeling and computer animation.

Neural perceptron-based Training and Classification of Acoustic Signal

  • Kim, Yoon-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • v.9 no.1
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    • pp.1133-1136
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    • 2005
  • The MPEG/audio standard results from three years of co-work by an international committe of high-fidelity audio compression experts in the Moving Picture Experts Group (MPEG/audio). The MPEG standard is rigid only where necessary to ensure interoperability. In this paper, a new approach of training and classification of acoustic signal is addressed. This is some what a fields of application aspects rather than technonical problems such as MPEG/codec, MIDI. In preprocessing, acoustic signal is transformmed using DWT so as to extract a feature parameters of sound such as loudness, pitch, bandwidth and harmonicity. these accoustic parameters are exploited to the input vector of neural perceptron. Experimental results showed that proposed approach can be used for tunning the dissonance chord.

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A Study on the Position Control of Permanent Magnet Sychronous Motor using the State Observer (상태관측기에 의한 영구자석동기전동기의 위치제어에 관한 연구)

  • Cho, Kwang-Seung;Park, Sung-Won;Moon, Baek-Young;Shin, Dong-Ryul;Woo, Jung-In
    • Proceedings of the KIEE Conference
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    • 2000.11b
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    • pp.378-380
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    • 2000
  • According to the rapid growth of high speed and precise industry the application of synchronous motor has been increased. In the application fields, the fast dynamic response is of prime importance. In particular, since the PMSM has characteristics of high speed, high thrust, it has used in high-performance servo drive. From these reasons, it is recently used for high precise position control, and machine tool. In this paper, using the state observer, robust vector position control method for the purpose of improving the system performance deterioration caused by parameter variations is proposed.

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A Nonlinear Synchronization Scheme for Hindmarsh-Rose Models

  • Kim, Jung-Su;Allgower, Frank
    • Journal of Electrical Engineering and Technology
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    • v.5 no.1
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    • pp.163-170
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    • 2010
  • Multiple subsystems are required to behave synchronously or cooperatively in many areas. For example, synchronous behaviors are common in networks of (electro-) mechanical systems, cell biology, coupled neurons, and cooperating robots. This paper presents a feedback scheme for synchronization between Hindmarsh-Rose models which have polynomial vector fields. We show that the problem is equivalent to finding an asymptotically stabilizing control for error dynamics which is also a polynomial system. Then, an extension to a nonlinear observer-based scheme is presented, which reduces the amount of information exchange between models.

Fuzzy-based Intelligent Expert Search for Knowledge Management Systems

  • Yang, Kun-woo;Huh, Soon-young
    • Proceedings of the KAIS Fall Conference
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    • 2003.11a
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    • pp.73-79
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    • 2003
  • In managing organizational tacit knowledge, recent researches have shown that it is more applicable in many ways to provide expert search mechanisms in KMS to pinpoint experts in the organizations with searched expertise. In this paper, we propose an intelligent expert search framework to provide search capabilities for experts in similar or related fields according to the user's information needs. In enabling intelligent expert searches, Fuzzy Abstraction Hierarchy (FAH) framework has been adopted, through which finding experts with similar or related expertise is possible according to the subject field hierarchy defined in the system. To improve FAH, a text categorization approach called Vector Space Model is utilized. To test applicability and practicality of the proposed framework, the prototype system, "Knowledge Portal for Researchers in Science and Technology" sponsored by the Ministry of Science and Technology (MOST) of Korea, was developed.

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Jacobi Operators with Respect to the Reeb Vector Fields on Real Hypersurfaces in a Nonflat Complex Space Form

  • Ki, U-Hang;Kim, Soo Jin;Kurihara, Hiroyuki
    • Kyungpook Mathematical Journal
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    • v.56 no.2
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    • pp.541-575
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    • 2016
  • Let M be a real hypersurface of a complex space form with almost contact metric structure (${\phi}$, ${\xi}$, ${\eta}$, g). In this paper, we prove that if the structure Jacobi operator $R_{\xi}= R({\cdot},{\xi}){\xi}$ is ${\phi}{\nabla}_{\xi}{\xi}$-parallel and $R_{\xi}$ commute with the structure tensor ${\phi}$, then M is a homogeneous real hypersurface of Type A provided that $TrR_{\xi}$ is constant.

The General Analysis of an Active Stereo Vision with Hand-Eye Calibration (핸드-아이 보정과 능동 스테레오 비젼의 일반적 해석)

  • Kim, Jin Dae;Lee, Jae Won;Sin, Chan Bae
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.5
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    • pp.83-83
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    • 2004
  • The analysis of relative pose(position and rotation) between stereo cameras is very important to determine the solution that provides three-dimensional information for an arbitrary moving target with respect to robot-end. In the space of free camera-model, the rotational parameters act on non-linear factors acquiring a kinematical solution. In this paper the general solution of active stereo that gives a three-dimensional pose of moving object is presented. The focus is to achieve a derivation of linear equation between a robot′s end and active stereo cameras. The equation is consistently derived from the vector of quaternion space. The calibration of cameras is also derived in this space. Computer simulation and the results of error-sensitivity demonstrate the successful operation of the solution. The suggested solution can also be applied to the more complex real time tracking and quite general and are applicable in various stereo fields.

The General Analysis of an Active Stereo Vision with Hand-Eye Calibration (핸드-아이 보정과 능동 스테레오 비젼의 일반적 해석)

  • 김진대;이재원;신찬배
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.5
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    • pp.89-90
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    • 2004
  • The analysis of relative pose(position and rotation) between stereo cameras is very important to determine the solution that provides three-dimensional information for an arbitrary moving target with respect to robot-end. In the space of free camera-model, the rotational parameters act on non-linear factors acquiring a kinematical solution. In this paper the general solution of active stereo that gives a three-dimensional pose of moving object is presented. The focus is to achieve a derivation of linear equation between a robot's end and active stereo cameras. The equation is consistently derived from the vector of quaternion space. The calibration of cameras is also derived in this space. Computer simulation and the results of error-sensitivity demonstrate the successful operation of the solution. The suggested solution can also be applied to the more complex real time tracking and quite general and are applicable in various stereo fields.

Named Entity Recognition with Structural SVMs and Pegasos algorithm (Structural SVMs 및 Pegasos 알고리즘을 이용한 한국어 개체명 인식)

  • Lee, Changki;Jang, Myungil
    • Annual Conference on Human and Language Technology
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    • 2010.10a
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    • pp.100-104
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    • 2010
  • 개체명 인식은 정보 추출의 한 단계로서 정보검색 분야 뿐 아니라 질의응답과 요약 분야에서 매우 유용하게 사용되고 있다. 본 논문에서는 structural Support Vector Machines(structural SVMs) 및 수정된 Pegasos 알고리즘을 이용한 한국어 개체명 인식 시스템에 대하여 기술하고 기존의 Conditional Random Fields(CRFs)를 이용한 시스템과의 성능을 비교한다. 실험결과 structural SVMs과 수정된 Pegasos 알고리즘이 기존의 CRFs 보다 높은 성능을 보였고(신뢰도 99%에서 통계적으로 유의함), structural SVMs과 수정된 Pegasos 알고리즘의 성능은 큰 차이가 없음(통계적으로 유의하지 않음)을 알 수 있었다. 특히 본 논문에서 제안하는 수정된 Pegasos 알고리즘을 이용한 경우 CRFs를 이용한 시스템보다 높은 성능 (TV 도메인 F1=85.43, 스포츠 도메인 F1=86.79)을 유지하면서 학습 시간은 4%로 줄일 수 있었다.

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Analysis of Airflows in a Room with Panoramic PIV (파노라마-PIV를 이용한 실내기류 해석)

  • Hwang Tae-Gyu;Doh Deog-Hee
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.12
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    • pp.1154-1160
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    • 2005
  • A panoramic-PIV system has been constructed for the analysis of the airflows in a room. Smoke is used as seeding particles and are visualized by a pulsed laser (Nd-Yag, 120 mJ). Panoramic images have been obtained by an image composition process using the two images obtained by the two cameras $(1k\times1k)$ that are viewing the wide measurement areas. Velocity vector fields have been obtained by the grey-level cross-correlation PIV method. Three room models $(L{\times}W{\times}H[mm^3],\;500\times500\times250,\;350\times350\times175,\;250\times250\times125)$ have been tested. The experimental results have proven that the constructed panoramic-PIV system can be used as a useful tool for analyzing the airflow characteristics in the room models.