• Title/Summary/Keyword: cylinder probability

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A NOTE ON THE INTEGRATION WITH RESPECT TO FINITELY ADDITIVE SET FUNCTIONS

  • Kim, Bong-Jin
    • The Pure and Applied Mathematics
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    • v.6 no.1
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    • pp.17-25
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    • 1999
  • In this paper, we investigate the properties of the Dunford-Schwartz integral (the integral with respect to a finitely additive measure). Though it is not equivalent to the cylinder integral, we can show that a cylinder probability v on (H, C) can be extend as a finitely additive probability measure $\hat{v}$ on a field $\hat{C}{\;}{\supset}{\;}C$ which is equivalent to the Dunford-Schwartz integral on ($H,{\;}\hat{C},{\;}\hat{v}$).

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Impact Buckling Reliability Analysis of Stiffened Cylinder With Initial Geometric Imperfection (기하학적 초기형상결함을 갖는 보강 원통의 충격좌굴 신뢰성 해석)

  • 김두기
    • Journal of KSNVE
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    • v.6 no.6
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    • pp.735-747
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    • 1996
  • In this paper, buckling reliability analyses of stiffened cylinder with random initial geometric imperfection under axial impact load are performed by the combined response surface method. The effect of random geometric imperfection on the failure probability and reliability is recognized quantitatively. Buckling reliability decreases with the increase of mean value, cov of initial geometric imperfection under the same external load. Buckling probability under impact load is greater than those under static load with the same condition. From the probabilistic characteristics of imapct buckling load, relation between reliability index and safety parameter can be obtained in addition to the relation between load and reliability index. And those results can be used to determine the range of required safety parameter and acceptable imperfaction.

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The Characteristics of Two-Dimensional Turbulent Wake Flow Past a Rectangular Cylinder (장방형주 후류의 2차원 난류특성)

  • 남청도;조석호;부정숙
    • Journal of Advanced Marine Engineering and Technology
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    • v.14 no.1
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    • pp.62-71
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    • 1990
  • Two-dimensional turbulent wake flow past a rectangular cylinder is investigated experimentally by using the linearized constant temperature hot-wire anemometer. Some of turbulent characteristics are obtained at the range of X=6B-500B downstream from the cylinder and the Reynolds number range is 500-2800. For the statistical treatment, autocorrelation coefficient, probability density function and power spectral density function are obtained by using the signal analyzer. It is clear that coherent structure of strong periodic eddies exists to the position of 20B downstream from the cylinder, and its feature is similar to round type as nearer to the cylinder while it is stretched longitudinally along with flow direction as the distance from the cylinder is increased to downstream.

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Study on Pedestrian Protection device in collision using Pneumatic cylinder and simple link mechanism (공압 실린더 및 단순 링크기구를 이용한 충돌 보행자 보호 장치에 관한 연구)

  • Noh, S.H.;Lee, D.R.
    • Journal of Power System Engineering
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    • v.12 no.4
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    • pp.64-71
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    • 2008
  • This study is on pedestrian protection device using pneumatic cylinder and simple link mechanism when vehicle collide with pedestrian. This study ensured the safety space between engine and hood after it applies to simple link mechanism and pneumatic cylinder. It can absorb the damage which measure the specific device if vehicle collide with pedestrian. Combination of simple link mechanism and pneumatic cylinder was more superior than the present pedestrian protection device. Simple link mechanism could confirm superior height and survival probability than when only cylinder operated. It also ensured enough space between engine and hood. And if a cylinder is not working because of old cylinder, poor repair or damage of accident vertical cylinder would be difficult to execute because there exists the irregular space between engine and hood. If simple link mechanism operates with only one cylinder it could ensure the regular space because simple link mechanism set up at the middle of hood. So this device could confirm high safety for pedestrian.

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Estimation of Probability Density Functions of Damage Parameter for Valve Leakage Detection in Reciprocating Pump Used in Nuclear Power Plants

  • Lee, Jong Kyeom;Kim, Tae Yun;Kim, Hyun Su;Chai, Jang-Bom;Lee, Jin Woo
    • Nuclear Engineering and Technology
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    • v.48 no.5
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    • pp.1280-1290
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    • 2016
  • This paper presents an advanced estimation method for obtaining the probability density functions of a damage parameter for valve leakage detection in a reciprocating pump. The estimation method is based on a comparison of model data which are simulated by using a mathematical model, and experimental data which are measured on the inside and outside of the reciprocating pump in operation. The mathematical model, which is simplified and extended on the basis of previous models, describes not only the normal state of the pump, but also its abnormal state caused by valve leakage. The pressure in the cylinder is expressed as a function of the crankshaft angle, and an additional volume flow rate due to the valve leakage is quantified by a damage parameter in the mathematical model. The change in the cylinder pressure profiles due to the suction valve leakage is noticeable in the compression and expansion modes of the pump. The damage parameter value over 300 cycles is calculated in two ways, considering advance or delay in the opening and closing angles of the discharge valves. The probability density functions of the damage parameter are compared for diagnosis and prognosis on the basis of the probabilistic features of valve leakage.

Direct Numerical Simulation of Mass Transfer in Turbulent Flow Around a Rotating Circular Cylinder (II) - Effect of Schmidt Number - (회전하는 원형단면 실린더 주위의 난류유동 물질전달에 대한)

  • Hwang Jong-Yeon;Yang Kyung-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.7 s.238
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    • pp.846-853
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    • 2005
  • In this paper, mass transfer in turbulent flow around a rotating circular cylinder is investigated by Direct Numerical Simulation for Schmidt numbers Sc=1 and 1670. Correlation between Sherwood and Reynolds number predicted agrees well with other experimental results over both Sc. Reynolds analogy identified at Sc=1 definitely causes a strong correlation between concentration fluctuation and streamwise velocity. For Sc=1670, it is found that positive small values of concentration fluctuations are observed more frequently than the case of Sc=1 particularly out of the range of Nernst diffusion layer in the viscous sub-layer. This fact is fully confirmed by detailed statistical study using a probability density function of concentration fluctuations.

An experimental Study of the Wake Flow Past a Rectangular Cylinder (長方形柱 後流에 關한 實驗的 硏究)

  • Nam, Cheong-Do
    • Journal of Advanced Marine Engineering and Technology
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    • v.15 no.3
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    • pp.45-56
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    • 1991
  • This paper describes characteristics of the flow pattern of the flow past a rectangular cylinder experimentally investigated. The width-to-length ratio of the section varried from 2 to4. For the statistical treatment, autocorrelation coefficient, probability density function and power spectral density function are obtained by the digital processing technic through on-line system with a hot wire anemometer. As a results, it was found that strong periodic coherent eddies structure is sustained to about 20H downstream from the cylinder. And nearer the cylinder in the wake, the number of turbulent eddies of a large scale coherent structure are comparatively much more dominant than that of a small scale one. By the analysis of power spectrum, It was cleared that there exists a certain range of the width to length ratio between 2.5 and 3 of which the flow pattern changes abruptly with a sudden discontinuity in Strouhal number.

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A Quantitative Analysis on Human Errors in Shifting Hazardous Materials of Semiconductor Plants (반도체공장의 위험물 교체작업시 인적과오에 대한 정량적 분석)

  • 임현교
    • Journal of the Korean Society of Safety
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    • v.12 no.4
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    • pp.161-168
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    • 1997
  • Most plants producing semiconductors use a lot of chemicals, hazardous materials, and explosive gases. Though those materials are hazardous too much, some works still have to be done manually by human workers. However, according to a historical survey, more than half industrial accidents of those plants resulted from human errors or malfunctions. Thus, this research aimed 1) to diagnose shifting hazardous materials of semiconductor plants, 2) to estimate failure probability of human workers through human reliability analysis, and 3) to find out the tasks on which educational emphasis should be put. Through personal interview and visiting working spots, shifting tasks were analyzed, and modelled into a 24-step work, and after that, THERP and ETA was applied. During the shifting work, estimated human failure probability under the assumption of independency, 2.3004E-05, underestimated that probability 8. l008E-05 which could be calculated under the assumption of dependency. And this analysis showed that gas leakage from an old cylinder occupies 78.27% in the case of independent failures whereas gas leakage from a new cylinder occupies 75.06% in the case of dependent failures. So it was concluded that dependency assumption may gloss real situations. In addition, confirming gauge of regulators and closing valves turned out to be the most important tasks than purge tasks.

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Bistatic Scattering from a Hemi-Spherically Capped Cylinder

  • Park, Sang-Hyun;La, Hyoung-Sul;Cho, Sung-Ho;Oh, Taek-Hwan;Kim, Young-Shin;Lee, Chang-Won;Na, Jung-Yul
    • The Journal of the Acoustical Society of Korea
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    • v.25 no.3E
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    • pp.115-122
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    • 2006
  • The bistatic scattering of an incident wave by a hemi-spherically capped cylinder is of particular interest because it has rarely been studied until the present day. The configuration of a hemi-spherically capped cylinder is similar to naval underwater weapons (submarines, mines, torpedos, etc.), but which is not exactly the same. This paper describes a novel laboratory experiment aimed at direct measurement of bistatic scattering by a hemi-spherically capped cylinder. Bistatic scattering by a hemi-spherically capped cylinder was measured in an acoustic water tank (5m long, 5m wide, 5m deep) using a high frequency projector (120kHz) and hydrophone. Measurements of monostatic scattering were also made under the same conditions. The bistatic scattering pattern by a hemi-spherically capped cylinder was measured against the incident angles $(0^{\circ},\;15^{\circ},\;20^{\circ},\;30^{\circ},\;45^{\circ},\;60^{\circ},\;90^{\circ})$ in order to verify various scattering pattern characteristics by the change of incident angle. The results indicate that the bistatic scattering TS at a wide scattering angle is much stronger than the mono static scattering TS. In bistatic scattering, the forward scattering TS is significantly stronger than the backward scattering TS, and the forward scattering pattern is also broader. In case of seven incident angles, the maximum value of forward scattering TS is about 14dB stronger than that of backward scattering TS. It is also found that forward scattering varies with the incident angle of sound to a much less extent than backscattering, and it is not seriously affected by the incident angle. These features could be the advantages of using forward scattering for detecting underwater targets at long range and increasing detection area and probability.