• 제목/요약/키워드: time domain data

검색결과 1,310건 처리시간 0.031초

3-Dimensional Vibration Measurement and Analysis of King Song-Dok Bell (성덕대왕 신종의 3차원 진동신호 측정 및 분석 결과)

  • Kim, Yang-Hann;Park, Yon-Kyu;Kim, Young-Key
    • The Journal of the Acoustical Society of Korea
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    • 제16권6호
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    • pp.41-47
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    • 1997
  • Beating phenomenon which is generated by two closely located natural frequencies is one of research tenet for King Song-Dok bell. In this paper, we investigate the vibration shape of these natural frequencies using very extensive experimental data. Vibration signals are sampled at 108 points around the bell using accelerometers. Measured signals are anlayzed in time and frequency domain. Twelve natural shapes under 800Hz are plotted.

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External Force Control for Two Dimensional Contour Following ; Part 1. A Linear Control Approach

  • Park, Young-Chil;Kim, Sungkwun
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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    • pp.130-134
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    • 1992
  • The ability of a robot system to comply to an environment via the control of tool-environment interaction force is of vital for the successful task accomplishment in many robot application. This paper presents the implementation of external force control for two dimensional contour following task using a commercial robot system. Force accommodation is used since a constraint imposed in our work is not to modify the commercial robot system. A linear, decoupled model of two dimensional contour following system in the discrete time domain is derived first. Then the experimental verification of linear control is obtained using a PUMA 560 manipulator with standard Unimation controller, Astek FS6-120A six axis wrist force sensor attached externally to the arm and LSI-11173 microcomputer. Experimentally obtained data shows that the RMS contact force error is 0.8246 N when following the straight edge and 2.3768 N when following 40 mm radius curved contour.

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Reception performance improvement of VSB in multipath channel using switched beamforming (선택 빔형성을 적용한 다중경로 환경 VSB 수신 성능 개선)

  • 배재휘;서재현;김주연;김승원
    • Proceedings of the IEEK Conference
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    • 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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    • pp.35-38
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    • 2003
  • We propose a switched beamforming to improve the reception performance of VSB system in severe Rayleigh fading channel. The VSB system has only about 3% of known training signal for the receiver in a data field and the reception performance of VSB receiver is degraded significantly when there are near-0 dB ghosts in receiving signal. The switched beamforming forms several beams in different directions and selects only one beam among them. For the selection of a beam with best channel condition for VSB equalizer, we extracted the channel profiles in time domain for all the beams by correlating the PN511 sequence in VSB field sync and selected optimal beam by comparing the channel profiles. The simulation results show that the proposed method improves the reception performance of VSB system in severe Rayleigh channel.

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Structural Damage Identification by Using Spectral Element Model (스펙트럴요소 모델을 이용한 구조손상규명)

  • 민승규;김정수;이우식
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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    • pp.366-373
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    • 2003
  • This paper introduces a frequency-domain method of structural damage identification. It is formulated in a general form to include the nonlinearity of damage magnitudes from the dynamic stiffness equation of motion for a beam structure. The appealing features of the present damage identification method are: (1) it requires only the frequency response functions measured from damaged structure as the input data, and (2) it can locate and quantify many local damages at the same time. The feasibility of the present damage identification method is tested through some numerically simulated damage identification analyses for a cantilevered beam with three piece-wise uniform damages.

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Modeling and Motion Control of Piezoelectric Actuator for the Inchworm : Part 2. Motion Control of Inchworm Using Sliding Mode Method (이송자벌레를 위한 압전소자의 모델링 및 운동제어 : 2. 슬라이딩 모드법에 의한 이송자벌레의 운동제어)

  • Kim, Young-Shik;Park, Euncheol;Kim, In-Soo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • 제15권7호
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    • pp.878-884
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    • 2005
  • This paper presents an algorithm for the precision motion control based on the dynamic characteristics of piezoelectric actuators in the inchworm. The dynamic characteristics are identified by the frequency domain modeling technique using the experimental data. For the motion control, the hysteresis behavior is compensated by the inverse hysteresis model. The dynamic stiffness of an inchworm is generally low compared to its driving condition, so mechanical vibration may degenerate the motion accuracy of the inchworm. The Sliding mode controller and the Kalman filter are designed for motion control of the inch-worm.

On Individual Wave Height Distribution of Ocean Waves (해양파의 개별파고 분포에 대하여)

  • Kim, Do-Young
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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    • pp.367-372
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    • 2006
  • If the sea is narrowband, the Rayleigh distribution introduced by Longuet-Higgins can be used for the individual wave height distribution. However the Rayleigh distribution over-predicts the probability of high waves. Longuet-Higgins introduced alternative form of the Rayleigh distribution with an empirical constant. The wave height distribution can be fitted well by one parameter Rayleigh distribution with a proper choice of the empirical constant. The empirical constant is the ratio of the significant wave height based the time domain analysis and the spectral analysis. Here we examine wave data which contain extreme waves. Once again we confirmed that extreme wave height distribution can be modelled well by a modified Rayleigh distribution.

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Deep Neural Network-Based Beauty Product Recommender (심층신경망 기반의 뷰티제품 추천시스템)

  • Song, Hee Seok
    • Journal of Information Technology Applications and Management
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    • 제26권6호
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    • pp.89-101
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    • 2019
  • Many researchers have been focused on designing beauty product recommendation system for a long time because of increased need of customers for personalized and customized recommendation in beauty product domain. In addition, as the application of the deep neural network technique becomes active recently, various collaborative filtering techniques based on the deep neural network have been introduced. In this context, this study proposes a deep neural network model suitable for beauty product recommendation by applying Neural Collaborative Filtering and Generalized Matrix Factorization (NCF + GMF) to beauty product recommendation. This study also provides an implementation of web API system to commercialize the proposed recommendation model. The overall performance of the NCF + GMF model was the best when the beauty product recommendation problem was defined as the estimation rating score problem and the binary classification problem. The NCF + GMF model showed also high performance in the top N recommendation.

A New Algorithm for An Efficient Implementation of the MDCT/IMDCT (MDCT/IMDCT의 효율적인 구현을 위한 새로운 알고리즘)

  • 조양기;이원표;인치호;김희석
    • Proceedings of the IEEK Conference
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    • 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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    • pp.2471-2474
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    • 2003
  • The modified discrete cosine transform (MDCT) and its inverse transform (IMDCT) are employed in subband/transform coding schemes as the analysis/synthesis filter bank based on time domain aliasing cancellation (TDAC). And they are the most computational intensive operations in layer III of the MPEG audio coding standard. In this paper, we propose a new efficient algorithm for the MDCT/IMDCT computation. It is based on the MDCT/IMDCT computation algorithm using the discrete cosine transforms (DCTs), and it employs two discrete cosine transform of type II(DCT-II) to compute the MDCT/IMDCT. In addition to, it takes advantage of ability in calculating the MDCT/IMDCT computation, where the length of a data block is divisible by 4. The proposed algorithm in this paper requires less calculation complexity than the existing methods. Also, it can be implemented by the parallel structure,, and its structure is particularly suitable for VLSI realization.

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Quadtree Based Image Compression in Wavelet Transform Domain (웨이브렛 변환 영역에서 쿼드트리 기반 영상압축)

  • 소이빈;조창호;이상효;이상철;박종우
    • Proceedings of the IEEK Conference
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    • 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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    • pp.2303-2306
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    • 2003
  • The Wavelet Transform providing both of the frequency and time information of an image is proved to be very much effective for the compression of images, and recently lot of studies on coding algorithms for images decomposed by the wavelet transform together with the multiresolution theory are going on. This paper proposes a Quadtree decompositon method of image compression applied to the images decomposed by wavelet transform by using the correlations between pixels .Since the coefficients obtained by the wavelet transform have high correlations between scales, the Quadtree method can reduce the data quantity effectively The experimental image with 256${\times}$256 size was used to compare the Performances of the existing and the proposed compression methods.

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Study on comparisons between PSS/E and Matlab Simulink/SimPower Result on network system data (PSS/E - Matlab Simulink/SimPower 간 순시치 시뮬레이션 비교에 관한 연구)

  • Yoo, Yeuntae;Kim, Kisuk;Lee, Changun;Jang, Gilsoo
    • Proceedings of the KIEE Conference
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    • 대한전기학회 2015년도 제46회 하계학술대회
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    • pp.249-250
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    • 2015
  • Technological advance of power elcetronic devices using semiconductor switches in last several decades, invoke the increase of switching devices' penetration in the system like STATCOM or HVDC and also, increase the difficulty to adjust switching characteristics in the virtual simulating configuration, which are not capable of reflect the detailed phenomena. To investigate harmful effect of switching devices into the grid, detailed modeling of power electronic devices are necessary, and the first step for entire grid modelling is simulate power system in time domain model. In this paper, simple two bus system with synchronous generator and infinite bus on the other side has been compromised in two simulation environment, using PSS/E and Matlab/Simulink. Comparing the result of two simulation result will give answers to the fundamental difference between two type of simulation environment.

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