• Title/Summary/Keyword: Multi Motion Data

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Characteristics of Sediment and Flow with Channel Patterns in Alluvial Rivers (충적하천(沖積河川)의 수로양상(水路樣相)에 따른 유사(流砂) 및 흐름특성(特性))

  • Lee, Jong Seok;Lee, Dae Cheol;Pai, Dong Man;Cha, Young Kee
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.14 no.5
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    • pp.1177-1189
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    • 1994
  • This paper aims to develop the numerical model for prediction of the channel migration by analyzing of sediment and flow characteristics with patterns of channel in alluvial rivers. Flow in rivers constitutes to be the meandering or the braided form and rarely straight channel through morphologically stable patterns with mutual actions between the flowing water and bed materials. In order to develop the model for simulation of the channel migration, the channels are divided into two types with positive or negative sign by the direction of curvature radius of the centerline channel ($r_c$). That is, the single bend-channel consists of only one curvature of positive or negative sign and the multi-bend channel consists of two more curvatures of positive or negative sign, respectively. The model analyzes the sediment and flow characteristics under the influence of superelevation, spiral motion, irregularity in bed topography and depth-averaged velocity of channels. For reliability of this model, the single bend-channel and the multi bend channel are compared with experiment data in other models and the measured field data in the Keum-River, respectively. As a result, the both com parisians turn out to be excellent.

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Multi-beam Echo Sounder Operations for ROV Hemire - Exploration of Mariana Hydrothermal Vent Site and Post-Processing (심해무인잠수정 해미래를 이용한 다중빔 음향측심기의 운용 - 마리아나 열수해역 탐사 결과 및 후처리 -)

  • Park, Jin-Yeong;Shim, Hyungwon;Lee, Pan-Mook;Jun, Bong-Huan;Baek, Hyuk;Kim, Banghyun;Yoo, Seong-Yeol;Jeong, Woo-Young
    • Journal of Ocean Engineering and Technology
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    • v.31 no.1
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    • pp.69-79
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    • 2017
  • This paper presents the operations of a multi-beam echo sounder (MBES) installed on the deep-sea remotely operated vehicle (ROV) Hemire. Hemire explored hydrothermal vents in the Forecast volcano located near the Mariana Trench in March of in 2006. During these explorations, we acquired profiling points on the routes of the vehicle using the MBES. Information on the position, depth, and attitude of the ROV are essential to obtain higher accuracy for the profiling quality. However, the MBES installed on Hemire does not have its own position and depth sensors. Although it has attitude sensors for roll, pitch, and heading, the specifications of these sensors were not clear. Therefore, we had to merge the high-performance sensor data for the motion and position obtained from Hemire into the profiling data of the MBES. Then, we could properly convert the profiling points with respect to the Earth-fixed coordinates. This paper describes the integration of the MBES with Hemire, as well as the coordinate conversion between them. Bathymetric maps near the summit of the Forecast volcano were successfully collected through these processes. A comparison between the bathymetric maps from the MBES and those from the Onnuri Research Vessel, the mother ship of the ROV Hemire for these explorations, is also presented.

Digital Hologram Compression Technique using Multi-View Prediction based on Image Accumulation (영상집적 기반의 다시점 부호화 기술을 이용한 디지털 홀로그램의 압축 기술)

  • Choi, Hyun-Jun;Seo, Young-Ho;Bae, Jin-Woo;Yoo, Ji-Sang;Kim, Hwa-Sung;Kim, Dong-Wook
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.10C
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    • pp.933-941
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    • 2006
  • In this paper, we proposed an efficient coding method for digital hologram (fringe pattern) acquired by a CCD camera or by computer generation using multi-view prediction technique and MPEG video compression standard technique. It proceeds each R, G, or B color component separately. The basic processing unit is a partial image segmented into the size of $N{\times}N$. Each partial image retains the information of the whole object. This method generates an assembled image for a row of the segmented and frequency-transformed partial images, which is the basis of the coding process. That is, a motion estimation and compensation technique of MPEG is applif:d to the reconstructed images from the assembled images with the disparities found during generation of assembled image and the original partial images. Therefore the compressed results are the disparity of eachpartial image to form the assembled image for the corresponding row, assembled image, and the motion vectors and the compensated image for each partial image. The experimental results with the implemented algorithm showed that the proposed method has NC (Normal Correlation) values about 4% higher than the previous method, by which ours has better compression efficiency. Consequently, the Proposed method is expected to be used effectively in the application areas to transmit the digital hologram data. can be identified in comparison with the previous researches and commercial IPs.

Automatic Multileaf Collimation Quality Assurance for IMRT using Electronic Portal Imaging

  • Jin, Ho-Sang;Jason W. Sohn;Suh, Tae-Suk
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2002.09a
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    • pp.305-308
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    • 2002
  • More complex radiotherapy techniques using multi leaf collimation(MLC) such as intensity-modulated radiation therapy(IMRT) has been increasing the significance of verification of leaf position and motion. Due to the reliability and robustness, quality assurance(QA) of MLC is usually performed with portal films. However, the advantage of ease of use and capability of providing digital data of electronic portal imaging devices(EPIDs) have attracted many attentions as alternatives of films for routine quality assurance in spite of the concerns about their clinical feasibility, efficacy, and the cost to benefit ratio. In our work, the method of routine QA of MLC using electronic portal imaging(EPI) was developed. The verification of availability of EPI images for routine QA was performed by comparison with those of the portal films which were simultaneously obtained when radiation was delivered and known prescription input to MLC controller. Specially designed test patterns of dynamic MLC were applied to image acquisition. Quantitative off-line analysis using edge detection algorithm enhanced the verification procedure in addition to on-line qualitative visual assessment. In conclusion, the EPI is available enough for routine QA with the accuracy of portal films.

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Navigation System of UUV Using Multi-Sensor Fusion-Based EKF (융합된 다중 센서와 EKF 기반의 무인잠수정의 항법시스템 설계)

  • Park, Young-Sik;Choi, Won-Seok;Han, Seong-Ik;Lee, Jang-Myung
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.7
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    • pp.562-569
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    • 2016
  • This paper proposes a navigation system with a robust localization method for an underwater unmanned vehicle. For robust localization with IMU (Inertial Measurement Unit), a DVL (Doppler Velocity Log), and depth sensors, the EKF (Extended Kalman Filter) has been utilized to fuse multiple nonlinear data. Note that the GPS (Global Positioning System), which can obtain the absolute coordinates of the vehicle, cannot be used in the water. Additionally, the DVL has been used for measuring the relative velocity of the underwater vehicle. The DVL sensor measures the velocity of an object by using Doppler effects, which cause sound frequency changes from the relative velocity between a sound source and an observer. When the vehicle is moving, the motion trajectory to a target position can be recorded by the sensors attached to the vehicle. The performance of the proposed navigation system has been verified through real experiments in which an underwater unmanned vehicle reached a target position by using an IMU as a primary sensor and a DVL as the secondary sensor.

Multibody Dynamics in Arterial System

  • Shin Sang-Hoon;Park Young-Bae;Rhim Hye-Whon;Yoo Wan-Suk;Park Young-Jae;Park Dae-Hun
    • Journal of Mechanical Science and Technology
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    • v.19 no.spc1
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    • pp.343-349
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    • 2005
  • There are many things in common between hemodynamics in arterial systems and multibody dynamics in mechanical systems. Hemodynamics is concerned with the forces generated by the heart and the resulting motion of blood through the multi-branched vascular system. The conventional hemodynamics model has been intended to show the general behavior of the body arterial system with the frequency domain based linear model. The need for detailed models to analyze the local part like coronary arterial tree and cerebral arterial tree has been required recently. Non-linear analysis techniques are well-developed in multibody dynamics. In this paper, the studies of hemodynamics are summarized from the view of multibody dynamics. Computational algorithms of arterial tree analysis is derived, and proved by experiments on animals. The flow and pressure of each branch are calculated from the measured flow data at the ascending aorta. The simulated results of the carotid artery and the iliac artery show in good accordance with the measured results.

Development of magnetocardiograph system using YBCO SQUID magnetometers (YBCO SQUID 자력계를 이용한 자기심장검사장치 개발)

  • Kim, I.S.;Oh, S.H.;Lim, H.K.;Lee, Y.H.;Lee, S.G.;Park, Y.K.
    • Progress in Superconductivity
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    • v.8 no.2
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    • pp.158-163
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    • 2007
  • YBCO do superconducting quantum interference device (SQUID) magnetometers based on bicrystal junctions have been fabricated for magnetocardiograph (MCG) measurements. We could fabricate YBCO SQUID magnetometers having magnetic field noise of about $20fT/Hz^{1/2}$ at white noise region. We have developed an MCG system employing the high performance SQUID magnetometers. The lightweight MCG system, requiring liquid nitrogen as a coolant, consists of 6-channel SQUID sensors, an adjustable patient bed with sliding motion, and data analyses software. The MCG system could record quite clear MCG signals in a room with moderate magnetic shielding. In normal operation with multi-position MCG measurements, we could obtain clear 48-point mappings of magnetic field map and current source map with high enough signal qualities far clinical trials.

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A Study on the Characteristics of the Tube-to-Support Dynamic Impact Force Measurement Facility (튜브와 지지대 사이의 동적상호 충격력 측정장치 특성규명에 관한 연구)

  • 김일곤;박진무
    • Journal of KSNVE
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    • v.5 no.1
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    • pp.95-106
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    • 1995
  • Flow-induced vibration in heat exchanger (or fuel rod) in nuclar power plant can cause dynamic interactions between tubes and tube supports resulting in fretting-wear. To increase the reliability and design life of heat exchanger components, design criteria that establish acceptable limits of vibration and minimize fretting wear are necessary. The fretting-wear rate is dependent upon material combination, contact configuration, environmental conditions and tube-to tube support dynamic interaction. It is demostrated that the fretting -wear rate correlates well with tube-to-support contact force or work rate. The tube-to-support dynamic interaction, which consists of dynamic contact forces and tube motion, is used to relate single-span wear data to real heat exchanger configurations consisting of multi-span tube bundles. This paper describes the test facility to measure tube-to-support dynamic impact force and reports its dynamic characteristics through the four impact tests - a force transduces independent and external impact tests, central ring inside impact test and additional cylinder impact test. Through the tests the impact parameter change dependent upon the material difference of impacting ball is studied, and the impact parameters of Force Transducer Assembly components are measured. And also the dynamic behavior of Force Transducer Assembly is analyzed. The force measurement technique herein is shown to provide a reasonable measure of dynamic contact forces.

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A Study on the Design of Low Back Muscle Evaluation System Using Surface EMG (표면근전도를 이용한 허리근육 평가시스템의 설계에 관한 연구)

  • Lee Tae-Woo;Ko Do-Young;Jung Chul-Ki;Kim In-Soo;Kang Won-Hee;Lee Ho-Yong;Kim Sung-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.54 no.5
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    • pp.338-347
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    • 2005
  • A computer-based low back muscle evaluation system was designed to simultaneously acquire, process, display, quantify, and correlate electromyographic(EMG) activity with muscle force, and range of motion(ROM) in the lumbar muscle of human. This integrated multi-channel system was designed around notebook PC. Each channel consisted of a time and frequency domain block, and T-F(time-frequency) domain block. The captured data in each channel was used to display and Quantify : raw EMG, histogram, zero crossing, turn, RMS(root mean square), variance, mean, power spectrum, median frequency, mean frequency, wavelet transform, Wigner-Ville distribution, Choi-Williams distribution, and Cohen-Posch distribution. To evaluate the performance of the designed system, the static and dynamic contraction experiments from lumbar(waist) level of human were done. The experiment performed in five subjects, and various parameters were tested and compared. This system could equally well be modified to allow acquisition, processing, and analysis of EMG signals in other studies and applications.

Development of Modeling for Dynamic Response of EDF System (EDF 시스템의 동적 특성 연구를 위한 모델링 개발)

  • Han, Kyu Seung;Park, Sun Kyu;Lee, In Won
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.5 no.1
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    • pp.218-227
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    • 2001
  • The purpose of this study was to estimate that the relations of weathering speed and shear strength of granite soil by tracing the weathering depth of granite soil from the very moment of its cutting. The results obtained this follows : This paper is about seismic performance of the EDF(Electricite De France) system, that is among various base isolator. A rational modeling of EDF system has been presented that used Nllink element. We get theoretical solutions of equation of motion of the system and compared with numerical solutions using a finite element program. The unification modeling is made by comparing with behavior using Newmark-${\beta}$ method when input earthquake acceleration data. Thus, a verified modeling will apply bridge structures or multi-degree of-freedom systems.

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