• Title/Summary/Keyword: Velocity Measurements

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A Study of Target Motion Analysis For a Passive Sonar System with the IMM (IMM을 이용한 수동소나체계의 기동표적추적기법 향상 연구)

  • 유필훈;송택렬
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.148-148
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    • 2000
  • In this paper the IMM(Interacting Multiple model) algorithm using the MGEKF(Modified Gain Extended Kalman Filter) which modes are variances of the process noises is proposed to enhance the performance of maneuvering target tracking with bearing and frequency measurements. The state are composed of relative position, relative velocity, relative acceleration and doppler frequency. The mode probability is calculated from the bearing and frequency measurements. The proposed algorithm is tested a series of computer simulation runs.

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Velocity Field Measurements Over A Lex/Delta Wing By Triple Axis Hot-Film Anemometry (3축 HOT-FILM 풍속계에 의한 연장된 앞전을 갖는 삼각날개 속도장의 측정)

  • Lee,Gi-Yeong;Son,Myeong-Hwan;Jang,Yeong-Il
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.9
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    • pp.1-8
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    • 2003
  • Velocity data were acquired at a series of stations in the chordwise direction above a delta wing with leading edge extension, using a triple axis hot film anemometry. Surveys normal to planform yield velocity field data at incidence angle of 24$^{\circ}$and 32$^{\circ}$at a centerline chord Reynolds number of $1.76{\times}10^6$. Experimental results of velocity measurements of mean velocity of three components gave a confidence to quantitative investigate the vortical flow field over a LEX-delta wing with this probe. The present experiments indicated the existence of both wing and LEX vortex where the local mean axial velocity is maximum. It also shown the development of secondary vortex of opposite sign of rotating above the wing surface near the leading edge. The insertion of probe across the flow field was found to have little influence on the position of the vortex core.

Reliability of Treadmill Exercise Testing in Adults With Chronic Hemiplegia and Elderly People

  • Kim, Nam-Joe;Lee, Suk-Min;Chung, Yi-Jung
    • Physical Therapy Korea
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    • v.14 no.4
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    • pp.84-90
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    • 2007
  • The purpose of this study was to assess the test-retest reliability of heart rate (HR) and velocity measurements during peak effort and free treadmill walking tests in older patients with gait-impaired chronic hemiparetic stroke and control group. Twenty-two adults (13 men, 9 women; mean age, $73.7{\pm}5.2$ yrs) with chronic hemiparetic stroke are the experimental group. Nineteen elderly people (5 men, 14 women; mean age, $72.3{\pm}3.5$ yrs) were recruited as control group. Patients had mild to moderate chronic hemiparetic gait deficits, making handrail support necessary during treadmill walking. Free and peak effort treadmill walking tests were measured and then repeated at least two days later. Reliability was calculated from HR and walking velocity during free and peak effort treadmill walking test. Among the people who had strokes, HR [ICC(2,1)=.85, r=.86] and velocity [ICC(2,1)=.93, r=.93] were good parameters during free testing. Maximal testing generated good results for HR [ICC(2,1)=.81, r=.82] and velocity [ICC(2,1)=.96, r=.96] with the chronic hemiparetic stroke. In elderly people, HR [ICC(2,1)=.59, r=.62] and velocity [ICC(2,1)=.77, r=.76] were moderately reliable during free testing. Maximal testing produced moderate parameters for HR [ICC(2,1)=.74, r=.74] and velocity [ICC(2,1)=.66, r=.66] in the elderly. This study provides that free and maximal treadmill testing produce highly reliable HR and velocity measurements in adults with chronic hemiplegia using minimal handrail support.

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A Study on the Laminar Burning Velocity and Flame Structure with H2 Content in a Wide Range of Equivalence Ratio of Syngas(H2/CO)/Air Premixed Flames (넓은 당량비 구간에서 수소함유량에 따른 합성가스(H2/CO)/공기 예혼합화염의 연소속도 및 화염구조에 관한 연구)

  • Jeong, Byeong-Gyu;Lee, Kee-Man
    • Journal of the Korean Society of Combustion
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    • v.19 no.1
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    • pp.17-28
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    • 2014
  • In this study, the laminar burning velocity of syngas fuel($H_2/CO$) and flame structure with various hydrogen contents were studied using both experimental measurements and detailed kinetic analysis. The laminar burning velocities were measured by the angle method of Bunsen flame configuration and the numerical calculations including chemical kinetic analysis were made using CHEMKIN Package with USC-Mech II. A wide range of syngas mixture compositions such as $H_2$ : CO = 10 : 90, 25 : 75, 50 : 50, 75:25 and equivalence ratios from lean condition of 0.5 to rich condition of 5.0 have been considered. The experimental results of burning velocity were in good agreement with previous other research data and numerical simulation. Also, it was shown that the experimental measurements of laminar burning velocity linearly increased with the increment of $H_2$ content although the burning velocity of hydrogen is faster than the carbon monoxide above 10 times. This phenomenon is attributed to the rapid production of hydrogen related radicals such as H radical at the early stage of combustion, which is confirmed the linear increase of radical concentrations on kinetic analysis. Particular concerns in this study are the characteristics of burning velocity and flame structure different from lean condition for rich condition. The decrease of OH radicals and double peaks are observed with $H_2$ content in rich condition once $H_2$ fraction exceeds over threshold.

Velocity Characteristics of Horizontal Saccadic Eye Movement (수평 Saccadic 안구운동의 속도 특성에 관한 연구)

  • 박상희;이상효
    • Journal of Biomedical Engineering Research
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    • v.3 no.1
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    • pp.17-22
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    • 1982
  • In this paper, peak velocity characteristics of saccadic eye movements were measured and analyzed as a velocity characteristics of horizontal saccadic eye movement system. Measurements were made with an infrared reflection method, and horizontal saccadic eye movements of 5 normal subject were recorded for the periodic and random pulse targets of 5$^{\circ}$, 10$^{\circ}$, 20$^{\circ}$ , and 30$^{\circ}$ amplitudes.

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Absolute Vehicle Speed Estimation considering Acceleration Bias and Tire Radius Error (가속도 바이어스와 타이어반경 오차를 고려한 차량절대속도 추정)

  • 황진권;송철기
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.6
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    • pp.234-240
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    • 2002
  • This paper treats the problem of estimating the longitudinal velocity of a braking vehicle using measurements from an accelerometer and wheel speed data from standard anti-lock braking wheel speed sensors. We develop and experimentally test three velocity estimation algorithms of increasing complexity. The algorithm that works the best gives peak errors of less than 3 percent even when the accelerometer signal is significantly biased.

Analysis and Comparison of Flow Rate Measurements Using Various Discharge Measuring Instrument and ADCP (다양한 유량 측정기기와 ADCP를 이용한 유량 비교 분석)

  • Ji, Ju-Yeon;Park, Seung-Yong;Lee, Gwang-Woo;Park, Gyeong-Min;Hwang, Soon-Hong;Kim, Dong-Ho;Lee, Young-Joon
    • Journal of Environmental Science International
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    • v.22 no.2
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    • pp.251-257
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    • 2013
  • Discharge data examine the process of hydrologic cycle and used significantly in water resource planning and irrigation and flood control planning. It makes high quality discharge data, they carry out research on standard and method of discharge measurement, and equipment improvement. Now various flow meters are utilized to make discharge data in Korea. However, accuracy of equipment and exprerimental research data from measurement are not enough. ADCP(Acoustic Doppler Current Profiler) have been introduced and utilized for flow measurements since the end of 1980's. ADCP flow method is a formal method for flow measurement can easily applyd to relatively large rivers gradually recognized. This equipment can measure the non-contact three-dimensional velocity and water depth data very quickly and efficiently. Also, spatial and temporal resolution of the data is more accurate than any other flow measurement methods which measure flow rate by velocity - area measurement method. In this paper, the velocity is measured using various flow meter and verified the effectiveness by applying from the ADCP in Geum-river. Various flow meters which are med for discharge measurements are VALEPORT002, FLOW TRACKER, PRICE AA and ADCP. The average of five times flow measurement result by ADCP was $10.412m^3/s$, with a standard deviation of 0.68. The repeat test by ADCP and comparison between ADCP and other flow devices to verify the most import factor, flow measurement accuracy. In the result, repeat test of the ADCP showed similar values, flow values were similar to other velocity device results and the average error is 7.7%.