• Title/Summary/Keyword: multi pitch

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Performance Analysis and Pitch Control of Dual-Rotor Wind Turbine Generator System (Dual-Rotor 풍력 발전 시스템 성능 해석 및 피치 제어에 관한 연구)

  • Cho, Yun-Mo;No, Tae-Soo;Jung, Sung-Nam;Kim, Ji-Yon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.7
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    • pp.40-50
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    • 2005
  • In this paper, preliminary results for performance prediction of a dual-rotor wind turbine generator system are presented. Blade element and momentum theories are used to model the aerodynamic forces and moments acting on the rotor blades, and multi-body dynamics approach is used to integrate the major components to represent the overall system. Not only the steady-state performance but the transient response characteristics are analyzed. Pitch control strategy to control the rotor speed and the generator output is proposed and its performance is verified through the nonlinear simulation.

Identification of bridge bending frequencies through drive-by monitoring compensating vehicle pitch detrimental effect

  • Lorenzo Benedetti;Lorenzo Bernardini;Antonio Argentino;Gabriele Cazzulani;Claudio Somaschini ;Marco Belloli
    • Structural Monitoring and Maintenance
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    • v.9 no.4
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    • pp.305-321
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    • 2022
  • Bridge structural health monitoring with the aim of continuously assessing structural safety and reliability represents a topic of major importance for worldwide infrastructure managers. In the last two decades, due to their potential economic and operational advantages, drive-by approaches experienced growing consideration from researcher and engineers. This work addresses two technical topics regarding indirect frequency estimation methods: bridge and vehicle dynamics overlapping, and bridge expansion joints impact. The experimental campaign was conducted on a mixed multi-span bridge located in Lombardy using a Ford Galaxy instrumented with a mesh of wireless accelerometers. The onboard time series were acquired for a number of 10 passages over the bridge,performed at a travelling speed of 30 km/h, with no limitations imposed to traffic. Exploiting an ad-hoc sensors positioning, pitch vehicle motion was compensated, allowing to estimate the first two bridge bending frequencies from PSD functions; moreover, the herein adopted approach proved to be insensitive to joints disturbance. Conclusively, a sensitivity study has been conducted to trace the relationship between estimation accuracy and number of trips considered in the analysis. Promising results were found, pointing out a clear positive correlation especially for the first bending frequency.

An ACLMS-MPC Coding Method Integrated with ACFBD-MPC and LMS-MPC at 8kbps bit rate. (8kbps 비트율을 갖는 ACFBD-MPC와 LMS-MPC를 통합한 ACLMS-MPC 부호화 방식)

  • Lee, See-woo
    • Journal of Internet Computing and Services
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    • v.19 no.6
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    • pp.1-7
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    • 2018
  • This paper present an 8kbps ACLMS-MPC(Amplitude Compensation and Least Mean Square - Multi Pulse Coding) coding method integrated with ACFBD-MPC(Amplitude Compensation Frequency Band Division - Multi Pulse Coding) and LMS-MPC(Least Mean Square - Multi Pulse Coding) used V/UV/S(Voiced / Unvoiced / Silence) switching, compensation in a multi-pulses each pitch interval and Unvoiced approximate-synthesis by using specific frequency in order to reduce distortion of synthesis waveform. In integrating several methods, it is important to adjust the bit rate of voiced and unvoiced sound source to 8kbps while reducing the distortion of the speech waveform. In adjusting the bit rate of voiced and unvoiced sound source to 8 kbps, the speech waveform can be synthesized efficiently by restoring the individual pitch intervals using multi pulse in the representative interval. I was implemented that the ACLMS-MPC method and evaluate the SNR of APC-LMS in coding condition in 8kbps. As a result, SNR of ACLMS-MPC was 15.0dB for female voice and 14.3dB for male voice respectively. Therefore, I found that ACLMS-MPC was improved by 0.3dB~1.8dB for male voice and 0.3dB~1.6dB for female voice compared to existing MPC, ACFBD-MPC and LMS-MPC. These methods are expected to be applied to a method of speech coding using sound source in a low bit rate such as a cellular phone or internet phone. In the future, I will study the evaluation of the sound quality of 6.9kbps speech coding method that simultaneously compensation the amplitude and position of multi-pulse source.

A Study of Characteristic of Electrical-magnetic and Neutron Diffraction of Long-wire High-superconductor for Reducing Energy Losses

  • Jang, Mi-Hye
    • Transactions on Electrical and Electronic Materials
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    • v.9 no.6
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    • pp.265-272
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    • 2008
  • In this paper, AC losses of long wire Bi-2223 tapes with different twist pitch of superconducting core were fabricated, measured and analyzed. These samples produced by a powder-in-tube method are multi-filamentary tape with Ag matrix. Also, it's produced by non-twist. The critical current measurement was carried out under the environment in Liquid nitrogen and in zero field by 4-prob method. And the Magnetic measurement was carried out under the environment of applied time-varying transport current by transport method. From experiment, the susceptibility measurements were conducted while cooling in a magnetic field. Flux loss measurements were conducted as a function of ramping rate, frequency and field direction. The AC flux loss increases as the twist-pitch of the tapes decreased, in agreement with the Norris Equation. Neutron-diffraction measurements have been carried out investigate the crystal structure, magnetic structures, and magnetic phase transitions in Bi-2223([Bi, Pb]:Sr:Ca:Cu:O).

Rhythm Game Design for Effective Music Education (리듬게임을 활용한 효과적인 음악교육 게임 제작)

  • Park, Seung-Ie;Kihl, Tae-Suk
    • Journal of Korea Game Society
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    • v.12 no.1
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    • pp.33-42
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    • 2012
  • This study is intended to design a rhythm game improving the student's capacity to learn and appreciate music. This game was tested in the music classes of an elementary school. The note patterns reflecting melody affected the perception of pitch, duration, and loudness of the music. This study also presented that the factor influencing students' immersion in music and learning music was the multi-sense of sight, hearing, and touch.

Emotion Recognition using Prosodic Feature Vector and Gaussian Mixture Model (운율 특성 벡터와 가우시안 혼합 모델을 이용한 감정인식)

  • Kwak, Hyun-Suk;Kim, Soo-Hyun;Kwak, Yoon-Keun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.762-766
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    • 2002
  • This paper describes the emotion recognition algorithm using HMM(Hidden Markov Model) method. The relation between the mechanic system and the human has just been unilateral so far. This is the why people don't want to get familiar with multi-service robots of today. If the function of the emotion recognition is granted to the robot system, the concept of the mechanic part will be changed a lot. Pitch and Energy extracted from the human speech are good and important factors to classify the each emotion (neutral, happy, sad and angry etc.), which are called prosodic features. HMM is the powerful and effective theory among several methods to construct the statistical model with characteristic vector which is made up with the mixture of prosodic features

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Mechanical Loads Analysis and Control of a MW Wind Turbine (MW 규모 풍력 터빈의 기계적 하중 특성 해석 및 제어)

  • Nam, Yoon-Su;Choi, Han-Soon
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.9
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    • pp.26-33
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    • 2010
  • A multi-MW wind turbine is a huge mechanical structure, of which the rotor diameter is more or less than 100 m. Rotor blades experience unsymmetric mechanical loads caused by the interaction of incoming wind with the tower and wind shear effect. These mechanical loads are transferred to the entire structure of the wind turbine and are known as the major reasons for shortening the life span of the wind turbine. Therefore, as the size of wind turbine gets bigger, the mitigation of mechanical loads becomes more important issue in wind turbine control system design. In this paper, a concept of an individual pitch control(IPC), which minimizes the mechanical loads of rotor blades, is introduced, and simulation results using IPC are discussed.

Analysis of Current Distribution of Multi-Layer HTSC Power Cable dut to Pitch length and winding direction (피치길이와 결선방향에 따른 다층 고온초전도 전력케이블의 전류분류 분석)

  • Lee Jong-Hwa;Lim Sung-Hun;Ko Seokcheol;Park Chung-Ryul;Han Byoung-Sung;Hwang Si Dole
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.1133-1135
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    • 2004
  • Superconducting transmission power cable is one of interesting parts in power application using high temperature superconducting wire. One of important parameters in high-temperature superconducting (HTSC) cable design is transport current distribution because it is related with current transmission capacity and ac loss. In this paper, the transport current and magnetic field distributions at conducting layers were investigated through the analysis of the equivalent circuit for HTSC power cable with shield layer. The transport current distribution due to the pitch length and winding direction was improved in case of HTSC power cable with shield layer.

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3-Axis Gyro Sensor based on Servo Motion Control System (3-Axis Gyro Sensor based on Servo Motion Control 시스템 개발)

  • Sun, Nana;Lee, Won-Bu;Park, Soo-Hong
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2010.05a
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    • pp.725-727
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    • 2010
  • For simulation of Boat motion, pitch, motion element of roll and yaw direction could simulated. The combination of the marine use various multi sensor surveillance system technology with the development of servo motion control algorithm and gyro sensor in six freedom motion is implemented to analyze the movement response. The stabilization of the motion control is developed and Nano driving Precision Pan-Tilt/Gimbal system is obtained from the security positioning cameras with ultra high speed device is used to carry out the exact behavior of the device.

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A Study on Multi-Pulse Speech Coding Method by Using V/S/TSIUVC (V/S/TSIUVC를 이용한 멀티펄스 음성부호화 방식에 관한 연구)

  • Lee See-Woo
    • Journal of Korea Multimedia Society
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    • v.7 no.9
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    • pp.1233-1239
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    • 2004
  • In a speech coding system using excitation source of voiced and unvoiced, it would be involved a distortion of speech qualify in case coexist with a voiced and an unvoiced consonants in a frame. This paper present a new multi-pulse coding method by using V/S/TSIUVC switching, individual pitch pulses and TSIUVC approximation-synthesis method in order to restrict a distortion of speech quality. The TSIUVC is extracted by using the zero crossing rate and individual pitch pulse. And the TSIUVC extraction rate was 91% for female voice and 96.2% for male voice respectively. The important thing is that the frequency information of 0.347kHz below and 2.813kHz above can be made with high quality synthesis waveform within TSIUVC. I evaluate the MPC use V/UV and the FBD-MPC use V/S/TSIUVC. As a result, I knew that synthesis speech of the FBD-MPC was better in speech quality than synthesis speech of the MPC.

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