• 대한환경공학회지
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• 제27권10호
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• pp.1065-1071
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• 2005

유체의 파속과 파형을 이용한 많은 누수탐지 기술들이 연구되고 있다. 본 연구에서는 파속을 계산하기 위해 천이류 방법을 이용하였고 누수지점의 탐지를 위해 주파수 분석방법을 개발하였다. 가압관망의 자료획득 시스템을 개발하였으며, 이를 통해 고주파 수압자료를 획득하였다. 이들 방법론은 측정과 모의 과정에서 발생되는 오차로 인한 불화실성을 적절히 처리할 수 있으며, 수압자료의 측정간을 근거로 누수의 예측지점을 추정할 수 있다. 본 연구에서 개발된 방법은 수압자료로부터 확보되는 정보를 기반으로, 누수가 동반된 천이현상에서 누수예측능력을 보여주고 있다.

• 천문학회보
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• 제43권2호
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• pp.41.1-41.1
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• 2018

We constrain cosmological parameters by combining three different power spectra measured from galaxy clustering, galaxy-galaxy lensing, and cosmic shear using the Deep Lens Survey (DLS). Two lens bins (centered at z~0.27 and 0.54) and two source bins (centered at z~0.64, and 1.1) containing more than one million galaxies are selected to measure the power spectra. We re-calibrate the initial photo-z estimation of the lens bins by matching with SHELS and PRIMUS and confirm its fidelity by measuring a cross-correlation between the bins. We also check the reliability of the lensing signals through the null tests, lens-source flipping and cross shear measurement. Residual systematic errors from photometric redshift and shear calibration uncertainties are marginalized over in the nested sampling during our parameter constraint process. For the flat LCDM model, we determine S_8=sigma_8(Omega_m/0.3)^0.5=0.832+-0.028, which is in great agreement with the Planck data. We also verify that the two independent constraints from the cosmic shear and the galaxy clustering+galaxy-galaxy lensing measurements are consistent with each other. To address baryonic feedback effects on small scales, we marginalize over a baryonic feedback parameter, which we are able to constrain with the DLS data alone and more tightly when combined with Planck data. The constrained value hints at the possibility that the AGN feedback in the current OWLS simulations might not be strong enough.

• 약학회지
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• 제52권6호
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• pp.480-487
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• 2008

We described an estimation of measurement uncertainty in quantitative analysis of 11-nor-9-carboxy-${\Delta}^9$-tetrahydrocannabinol (THCCOOH), the major metabolite of ${\Delta}^9$-tetrahydrocannabinol, in urine sample by solid-phase extraction (SPE) and GC/MS detection. The analytical results were compared and the different contributions to the uncertainty were evaluated. Inter-day and inter-person validation were performed using statistical analysis of several indicative factors. Measurement uncertainty associated with target analyte in real forensic samples was estimated using quality control (QC) data. Traceability of measurement was established through traceable standards, calibrated volumetric glassware and volume measuring device. The major factors of contribution to combined standard uncertainty, were calibration linearity, inter-day repeatability and inter-person reproducibility, while those associated with preparation of analytical standards and sampling volume were not so important considering the degree of contribution. Relative combined standard uncertainties associated with the described method was 12.05% for THCCOOH.

• 한국태양에너지학회 논문집
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• 제36권4호
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• pp.11-20
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• 2016

For accurate wind resource assessment and wind turbine performance test, it is essential to secure wind data covering a rotor plane of wind turbine including a hub height. In general, we can depict wind speed profile by extrapolating or interpolating the wind speed data measured from a meteorological tower where multiple anemometers are mounted at different heights using a power-law of wind speed profile. The most important parameter of a power-law equation is a vertical wind profile exponent which represents local characteristics of terrain and land cover. In this study, we calculated diurnal vertical wind profile exponents of 8 locations in Jeju Island who possesses excellent wind resource according to the GUM (Guide to the Expression of Uncertainty in Measurement) to evaluate its uncertainty. Expanded uncertainty is calculated by combined standard uncertainty, which is the result of composing type A standard uncertainty with type B standard uncertainty. Although pooled standard deviation should be considered to derive type A uncertainty, we used the standard deviation of vertical wind profile exponent of each day avoiding the difficult of uncertainty evaluation of diurnal wind profile variation. It is anticipated that the evaluated uncertainties of diurnal vertical wind profile exponents at 8 locations in Jeju Island are to be registered as a national standard reference data and widely used in the relevant areas.

• 한국물환경학회지
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• 제29권5호
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• pp.681-690
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• 2013

Watershed models have been increasingly used to support an integrated management of land and water, non-point source pollutants, and implement total daily maximum load policy. However, these models demand a great amount of input data, process parameters, a proper calibration, and sometimes result in significant uncertainty in the simulation results. For this reason, uncertainty analysis is necessary to minimize the risk in the use of the models for an important decision making. The objectives of this study were to evaluate three different uncertainty analysis algorithms (SUFI-2: Sequential Uncertainty Fitting-Ver.2, GLUE: Generalized Likelihood Uncertainty Estimation, ParaSol: Parameter Solution) that used to analyze the sensitivity of the SWAT(Soil and Water Assessment Tool) parameters and auto-calibration in a watershed, evaluate the uncertainties on the simulations of runoff and sediment load, and suggest alternatives to reduce the uncertainty. The results confirmed that the parameters which are most sensitive to runoff and sediment simulations were consistent in three algorithms although the order of importance is slightly different. In addition, there was no significant difference in the performance of auto-calibration results for runoff simulations. On the other hand, sediment calibration results showed less modeling efficiency compared to runoff simulations, which is probably due to the lack of measurement data. It is obvious that the parameter uncertainty in the sediment simulation is much grater than that in the runoff simulation. To decrease the uncertainty of SWAT simulations, it is recommended to estimate feasible ranges of model parameters, and obtain sufficient and reliable measurement data for the study site.

• 디지털콘텐츠학회 논문지
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• 제16권3호
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• pp.463-470
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• 2015

최근 개인선량계로 사용이 증가하고 있는 수동형 선량계인 OSLD와 능동형 선량계인 EPD의 상대 반응도(relative response), 측정 불확도(uncertainty of measurement)를 계산하여 방향의존성(angular dependence)을 비교, 분석하였다. OSLD는 수평, 수직방향의 $0^{\circ}{\sim}{\pm}90^{\circ}$ 범위에서 평균 상대 반응도는 0.97, 0.95의 작은 변화를 보였고 방향의존성에 대한 불확도는 0.65, 0.62로 전체 불확도에 미치는 영향은 미미한 것으로 판단되었다. EPD는 $0^{\circ}{\sim}{\pm}60^{\circ}$ 범위에서 수평, 수직방향 평균 상대 반응도는 0.94, 0.97로 확인되어 IEC 61526 규정을 만족하였다. 방향의존성에 대한 불확도는 수평, 수직방향에서 0.44, 0.40로 전체 불확도에 미치는 영향은 미미하였다. 그러나 수평방향에서 $+90^{\circ}$, $-90^{\circ}$ 방향의 상대 반응도는 0.60, 0.37이고 수직방향에서 $+90^{\circ}$ 방향의 반응도는 0.06으로 반응도의 큰 변화를 관찰할 수 있었다. OSLD의 방향 의존성은 $0^{\circ}{\sim}{\pm}90^{\circ}$ 범위까지 EPD에 비해 우수하였으며 EPD의 경우 구조적 특징으로 반응도가 급변하는 특정방향이 존재하였다. 따라서 수동형선량계와 보조선량계의 병행사용이 개인피폭선량측정의 정확도를 기할 수 있을 것으로 판단된다.

• 한국지반공학회논문집
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• 제23권5호
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• pp.29-41
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• 2007

본 연구에서는 굴착이 진행 중인 터널 시공현장에서 계측변위를 활용하여 신속하게 터널의 안정성을 정량적으로 평가할 수 있는 기술을 새롭게 제안하였다. 이를 위해 먼저, 현재 국내외적으로 터널 시공현장에서 활용하고 있는 계측관리지침 사례를 조사하였다. 그러나 이들 지침은 그 근거가 뚜렷하지 못하고, 터널시공현장마다 서로 달라 통일적인 관리가 이루어지지 못할 뿐만 아니라 터널 계측과 관련된 다양한 제약으로 인해 현장 실무에서 활용도와 그 중요성이 높지 않은 것을 알 수 있었다. 터널굴착에 의해 발생하는 변위에 대한 기준 설정을 위해서 본 연구에서는 한계변형률 개념을 새롭게 도입하였으며 이를 활용하여 시공 중인 터널의 안정성 평가 기법을 새롭게 제안하였다. 또한 한계변형률 개념을 터널 실무에 활용하기 위해서, 지반굴착에 의해 발생하는 변위발생 특징을 종합적으로 검토하였으며, 터널굴착에 의해 발생하는 총변위를[굴착전 변위], [계측전 변위], [계측변위]로 구분하여 이들 각각에 대한 특성을 살펴보았다. 마지막으로 시공중인 터널에 대하여 한계변형률 개념을 도입하여 현장 계측결과를 활용하는 방안에 대하여 구체적으로 언급하였으며 이를 현재 국내의 계측현황 조사를 토대로 그 활용방안에 대해 기술하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.667-672
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• 2009

Gathering information and systemization of infrastructure disaster management is to reduce uncertainties in making decisions and maximize the number of alternations. The key objects of a sensor-based progress report and propagation automation systems are to provide objective data, realize and support decision making and deliver them to a certain area, department, manager and other people rapidly. The major findings and results of this study are as follows. 1) Application of international standard-based alerting protocol(CAP; Common Alerting Protocol). 2) Development of database of existing progress report and propagation manual in order to achieve networking of safety management on major social infrastructure of the nation. 3) Development middleware application programs to progress report and propagation data using SMS, FAX, EMS, VMS, MMS.

• 한국지진공학회논문집
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• 제22권3호
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• pp.201-210
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• 2018

The improvement in computing systems and sensor technologies devotes to conduct data-driven structural health monitoring algorithms for existing civil infrastructures. Despite of the development of techniques, the uncertainty oriented from the measurement results in the discrepancy to the actual structural parameters and let engineers or decision makers hesitate to adopt such techniques. Many studies have shown that the modal identification results can be affected by the uncertainties due to the applied methods and the types of loading. This paper aims to compare the performance of modal identification methods using Structural Modal Identification Toolsuite (SMIT) which has been developed to facilitate multiple identification methods with a user-friendly designed platform. The data fed into SMIT processes three stages for the comprehensive identification including preprocessing, eigenvalue estimation, and post-processing. The seismic and white noise response for shear frame model was obtained from numerical simulation. The identified modal parameters is compared to the actual modal parameters. In order to improve the quality of coherence in identified modal parameters, several hurdles including modal phase collinearity and extended modal amplitude coherence were introduced. Numerical simulation conducted on the 5 dof shear frame model were used to validate the effectiveness of using these parameters.

• 제어로봇시스템학회논문지
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• 제13권7호
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• pp.637-648
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• 2007

This paper presents a sensor fusion method based on indirect Kalman filter(IKF) for error compensation of low-cost inertial sensors and its application to the determination of attitude and position of small flying robots. First, the analysis of the measurement error characteristics to zero input is performed, focusing on the bias due to the temperature variation, to derive a simple nonlinear bias model of low-cost inertial sensors. Moreover, from the experimental results that the coefficients of this bias model possess non-deterministic (stochastic) uncertainties, the bias of low-cost inertial sensors is characterized as consisting of both deterministic and stochastic bias terms. Then, IKF is derived to improve long term stability dominated by the stochastic bias error, fusing low-cost inertial sensor measurements compensated by the deterministic bias model with non-inertial sensor measurement. In addition, in case of using intermittent non-inertial sensor measurements due to the unreliable data link, the upper and lower bounds of the state estimation error covariance matrix of discrete-time IKF are analyzed by solving stochastic algebraic Riccati equation and it is shown that they are dependant on the throughput of the data link and sampling period. To evaluate the performance of proposed method, experimental results of IKF for the attitude determination of a small flying robot are presented in comparison with that of extended Kaman filter which compensates only deterministic bias error model.