• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
• /
• pp.5-7
• /
• 2006

In this paper, we analyzed the elements of measurement uncertainty on electrical performance test which are the most important things in photovoltaic module performance test. Repeating the performance test by 6 men, the measurement uncertainty could be calculated. In this experiment, Solar Simulator (A-Class pulse type) used for domestic certificate test of PV module is Pasan IIIb (Balval, Switzerland). The possible elements of the measurement uncertain that could effect electrical performance test of PV module are reference cell, spectrum correction, error from measurement repetition, test condition, stability and uniformity of artificial solar simulator. To find the measurement uncertainty, 6 men repeated the test by 10 times. And the results were that numerical average value was 124.44W and measurement uncertainty was $124.44W{\pm}0.75W$ with 95% confidence level for 125W PV module.

• Journal of Power Electronics
• /
• 제13권5호
• /
• pp.814-828
• /
• 2013

The LCL resonant inductive power transfer (IPT) system is increasingly used because of its harmonic filtering capabilities, high efficiency at light load, and unity power factor feature. However, the modeling and controller design of this system become extremely difficult because of parameter uncertainty, high-order property, and switching nonlinear property. This paper proposes a frequency and load uncertainty modeling method for the LCL resonant IPT system. By using the linear fractional transformation method, we detach the uncertain part from the system model. A robust control structure with weighting functions is introduced, and a control method using structured singular values is used to enhance the system performance of perturbation rejection and reference tracking. Analysis of the controller performance is provided. The simulation and experimental results verify the robust control method and analysis results. The control method not only guarantees system stability but also improves performance under perturbation.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제54권2호
• /
• pp.81-86
• /
• 2005

In this paper we consider an optimal configuration problem for redundant inertial sensors which have uncertainty such as misalignment, scale factor error. The optimal configuration problem is treated from the viewpoint of navigation accuracy. We propose a necessary and sufficient condition for the optimal configuration of redundant sensors with no uncertainty, and a sufficient condition for the optimal configuration of redundant sensors with uncertainty. Finally we propose a condition for the optimal configuration based both navigation performance and FDI(fault detection and isolation).

• 대한안전경영과학회지
• /
• 제13권2호
• /
• pp.267-273
• /
• 2011

Since 'The Act on Private Investment of The Infrastructure' was established in 1994, private investment as well as government's investment in transport infrastructure has been active. However investment in transport infrastructure has more risks than others' due to uncertainty both in traffic volume and in construction cost. In the current appraisal procedure of deciding transportation infrastructure investment, instead of risk management, the sensitivity analysis considering only the changes of benefit, cost and social discount rate which are main factor affecting economic feasibility is carried out. Therefore the uncertainty of various factors affecting demand, cost and benefit are not considered in feasibility study. In this study the problems in current investment appraisal system were reviewed. Using Delphi technique the major factors which have high uncertainty in feasibility study were surveyed and then improvement plan was suggested in the respective of classic 4 step demand forecasting method. The range estimation technique was also mentioned to deal with the uncertainty of the future.

• Journal of the Korean Physical Society
• /
• 제73권9호
• /
• pp.1247-1254
• /
• 2018

We study the uncertainty stemming from different theoretical models in the spectroscopic factors extracted from experiments. We use three theoretical approaches, the distorted wave Born approximation (DWBA), the adiabatic distorted wave approximation (ADWA) and the continuum discretized coupled-channels method (CDCC), and analyze the $^{12}C(d,p)^{13}C$, $^{14}C(d,p)^{15}C$ reactions. We find that the uncertainty associated with the adopted theoretical models is less than 20%. We also investigate the contribution from the remnant term and observe that it gives less than 10% uncertainty. We finally make an attempt to explain the discrepancy in the spectroscopic factors of $^{17}C(\frac{3}{2}^+)$ between the ones extracted from experiments and from shell model calculations by analyzing the $^{16}C(d,p)^{17}C$ reaction.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2005년도 연구개발 발표회 논문집
• /
• pp.287-294
• /
• 2005

Flow rate measurement uncertainties of the ultrasonic flow meter are generally influenced by many different factors, such as Reynolds number, flow distortion, turbulence intensity, wall surface roughness, velocity integration method along the acoustic paths, and transducer installation method, etc. Of these influencing factors, one of the most important uncertainties comes from the velocity integration method. In the present study, a optimization weighting factor method for 5-chord, which is given by a function of the chord locations of acoustic paths, is employed to obtain the mean velocity in the flow through a pipe. The power law profile is assumed to model the axi-symmetric pipe flow and its results are compared with the present weighting factor concept. For an asymmetric pipe flow, the Salami flow model is applied to obtain the velocity profiles. These theoretical methods are also compared with the previous Gaussian, Chebyshev, and Tailor methods. The results obtained show that for the fully developed turbulent pipe flows with surface roughness effects, the present weighting factor method is much less sensitive than Chebyshev and Tailor methods, leading to a better reliability in flow rate measurement using the ultrasonic flow meters.

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2019년도 춘계학술논문요약집
• /
• pp.157-158
• /
• 2019

• 한국환경농학회지
• /
• 제39권3호
• /
• pp.228-236
• /
• 2020

BACKGROUND: The closed chamber method is the most commonly used for measuring greenhouse gas emissions from rice fields. This method has the advantages of being simple, easily available and economical. However, a measurement result using the chamber method is an estimated value and is complete when the uncertainty is estimated. The methane emissions from a rice paddy account for the largest portion of the greenhouse gas emissions in the agriculture sectors. Although assessment of uncertainty components affecting methane emission from a rice paddy is necessary to take account of dispersion characteristics, research on these uncertainty components is very rare to date. The goal of this study was to elucidate influencing factors on measurement uncertainty of methane concentrations measured by a closed automated chamber system from a rice paddy. METHODS AND RESULTS: The methane sampling system is located in the rice paddy in Gyeonggi-do Agricultural Research and Extension Services (37°13'15"N, 127°02'22"E). The primary measurement uncertainty components influencing methane concentrations (influencing factors) investigated in this research were repeatability, reproducibility and calibration in the aspects of methane sampling and analytical instrumentation. The magnitudes of the relative standard uncertainty of each influencing factor were quantified and compared. CONCLUSION: Results of this study showed what influencing factors were more important in determination of methane concentrations measured using the chamber system and analytical instrumentation located in the monitoring site. Quantifying the measurement uncertainty of the methane concentrations in this study would contribute to improving measurement quality of methane fluxes.

• 한국환경농학회지
• /
• 제39권3호
• /
• pp.237-245
• /
• 2020

BACKGROUND: The closed chamber method is the most commonly used for measuring greenhouse gas emissions from upland fields. This method has the advantages of being simple, easily available and economical. However, uncertainty estimation is essential for accurate assessment of greenhouse gas emissions and verification of emission reductions. The nitrous oxide emissions from upland field is very important for the nitrogen budget in the agriculture sectors. Although assessment of uncertainty components affecting nitrous oxide emission from upland field is necessary to take account of dispersion characteristics, research on these uncertainty components is very rare to date. This study aims at elucidation of influencing factors on measurement uncertainty of nitrous oxide concentrations measured by an automated open closed chamber method from upland field. METHODS AND RESULTS: The nitrous oxide sampling system is located in the upland field in Gyeonggi-do Agricultural Research and Extension Services (37°13'22"N, 127°02'22"E). The primary measurement uncertainty components influencing nitrous oxide concentrations (influencing factors) investigated in this research are repeatability, reproducibility and calibration in the aspects of nitrous oxide sampling and analytical instrumentation. The magnitudes of the relative standard uncertainty of each influencing factor are quantified and compared. CONCLUSION: Results of this study show what influencing factors are more important in determination of nitrous oxide concentrations measured using the automated open closed chambers located in the monitoring site. Quantifying the measurement uncertainty of the nitrous oxide concentrations in this study would contribute to improving measurement quality of nitrous oxide fluxes.

• 한국산림과학회지
• /
• 제102권4호
• /
• pp.477-483
• /
• 2013

본 연구의 목적은 몬테 카를로 시뮬레이션을 이용하여 소나무 탄소배출계수 자료의 확률밀도를 추정하고 불확도를 제시하는데 있다. 이용된 탄소배출계수는 목재기본밀도, 바이오매스확장계수, 뿌리함량비이고 4개의 확률밀도 함수(정규분포, 로그정규분포, 감마분포, 와이불 분포)를 고려하였다. 2-표본 콜모그로프-스미르노프 검정통계량과 누적밀도그림을 비교하여 최적의 확률밀도함수를 선정하고 상한과 하한의 불확도를 제시하였다. 본 연구의 결과에 의하면, 각 탄소배출계수에서 추정된 확률밀도함수는 강원지방소나무에서 목재기본밀도는 감마분포, 바이오매스확장계수는 로그정규분포, 뿌리함량비는 정규분포이고 중부지방소나무에서 목재기본밀도는 정규분포, 바이오매스확장계수는 감마분포, 뿌리함량비는 감마분포를 나타내었다. 강원지방소나무 탄소배출계수의 불확도는 상한에서 62.1%, 하한에서 -52.6%이고 중부지방소나무는 상한에서 43.9%, 하한에서 -34.5%를 나타내었다.