• Journal of the Society of Naval Architects of Korea
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• v.30 no.3
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• pp.75-89
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• 1993

The present paper describes an application of UA(Uncertainty Analysis) to seakeeping model test, basically according to the Performance Test Code of ASME(American Society of Mechanical Engineers), in which all the possible error sources involved in the preparation of test, calibration of instruments, data acquisition and analysis are quantified, and summed up with error propagation coefficients to the final uncertainties. The differences between the static test such as resistance and propulsion test and the dynamic test like seakeeping test are clearly identified during all the procedures of UA and asymmetric bias errors are considered. The DRE(data reduction equation) subject to present UA are the heave and pitch response amplitude operator and nondimensionalized absolute frequency. The usefulness of UA in seakeeping test were confirmed not only for quantifying errors and improving measurement accuracy but also for the validation of various seakeeping analysis tools.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.185-194
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• 2015

This study was performed to establish a single residue analytical method for determining fungicide carpropamid residues in various agricultural commodities. Korean cabbage, apple, brown rice and green pepper were selected as representative crops. Samples were homogenized, extracted with acetone and purified by liquid-liquid partition and Florisil column chromatography. Carpropamid residues were analyzed at 220 nm with reversed phase HPLC equipped octylsilyl and octadecylsilyl column and confirmed using mass spectrometry. ILOQ (Instrumental limit of quantitation) of carpropamid was 2 ng and MLOQ (Method LOQ) was 0.02 mg/kg. Mean recoveries from four kinds of crop samples fortified at three levels (MLOQ, 10LOQ, 100LOQ) in triplicate were in the range of 84~112%. Relative standard deviations of the analytical method were all less than 10%, irrespective of crop types.

• Journal of Korea Multimedia Society
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• v.16 no.6
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• pp.700-707
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• 2013

In this paper, we propose a non-rigid registration method of lung parenchyma in temporal chest CT scans using region binarization modeling and locally deformable model. To cope with intensity differences between CT scans, we segment the lung vessel and parenchyma in each scan and perform binarization modeling. Then, we match them without referring any intensity information. We globally align two lung surfaces. Then, locally deformable transformation model is developed for the subsequent non-rigid registration. Subtracted quantification results after non-rigid registration are visualized by pre-defined color map. Experimental results showed that proposed registration method correctly aligned lung parenchyma in the full inspiration and expiration CT images for ten patients. Our non-rigid lung registration method may be useful for the assessment of various lung diseases by providing intuitive color-coded information of quantification results about lung parenchyma.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1804-1808
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• 2008

최적유역관리 및 수질개선을 목표로 시행되고 있는 오염총량관리제도의 실질적인 효과를 달성하기 위해서는 해당 유역의 현황, 오염물질 배출특성 규명, 기준유량 및 기준수질의 산정이 요구되며, 하천 수리 수문 수질 모형화를 위한 장기간의 수질.유량 변동의 조사 및 분석이 선차적인 과제이다. 환경부는 오염총량관리제의 효율적인 추진을 위해 2004년 8월부터 현재까지 8일 간격(30회 이상/년)으로 오염총량관리 단위유역 41개 지점과 시도요구 6개 지점 등 총 47개의 지점에 대해 직 간접적으로 유량자료를 생성하고 있다. 이에 따라 관측한 수질 및 유량 자료는 단위유역별 오염부하량 산정, 삭감부하량 할당 및 이행평가에 활용하고 있는 상태이다. 또한 건설교통부, 수자원공사 등의 수문관측 기관에서는 도산, 낙동, 금호 등의 단위유역 지점에 대한 유량측정을 실시하여 주요 수자원계획시 기초자료로 활용하고 있다. 본 연구는 낙동강 유역의 기존 건설교통부, 수자원공사 관측망 측점지점에 대한 자료의 결측수 및 결측율, 수위-유량 관계곡선식 등의 정확도를 표준오차 및 불확실도를 정량적으로 산정하여 유량측정결과의 오염 총량과리를 위한 이용 가능성을 평가 및 소개하고자 한다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.10
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• pp.60-67
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• 1990

This paper proposes a model-based fault detection method for linear/nonlinear system having modelling errors, nonlinearities and measurement noise. The system model is represented by the unified operator [5] in order to apply to both the continuous-time and discrete-time problems. The fault detection method suggested here accounts for the effects of noise, model mismatch and nonlinearities. Modelling errors are depicted by additive forms and the nominal model denominator is fixed via prior experiments in order to quantify the nucertainty bound on the parameter estima-tion. The least square method is used to estimate the numerator parameters of the nominal model. performance than traditional methods.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.378-381
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• 2011

대표적 가스계 소화약제인 $CO_2$의 소화기구(Extinguishing mechanism)를 재조명하기 위하여, $CH_4$/air 저 신장율 대향류 확산화염을 대상으로 $CO_2$가 소화에 미치는 영향에 대한 수치해석이 수행되었다. 부력이 지배적인 화염의 소화현상은 복사 열손실에 의해 큰 영향을 받기 때문에, 소화농도 예측에 대한 복사모델의 성능평가가 우선적으로 이루어졌다. 주요 결과로서, 공기류에 첨가된 $CO_2$의 소화농도는 복사모델이 고려되지 않은 경우 과다 예측되는 반면에, 간략화된 광학적으로 얇은 근사(Optically thin approximation) 모델과 비교적 높은 정확도를 갖는 좁은 밴드(Statistical narrow band) 모델은 실험의 오차범위 내에서 큰 차이를 보이지 않았다. $CO_2$가 소화에 미치는 순수 희석효과, 희석에 의한 복사효과, 화학적 효과 및 열적효과를 정량적으로 분석하기 위하여 가상의 소화약제의 개념을 도입하였다. 이를 통해 화염의 총괄신장율에 따른 $CO_2$ 소화효과에 대한 구체적인 이해가 시도되었다.

• Journal of the Korean Chemical Society
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• v.17 no.2
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• pp.126-129
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• 1973

An amperometric method has been developed for the titration of silver with 2,5-dimercapto-1,3,4,-thiadiazole in ammonical solution (1N) using rotating platinum electrode as an indicator electrode and the mercury-mercury (II) iodide as reference electrode. Direct titration of milligram amount of silver (0.05-1.0mg) is possible in the presence of a number of foreign ions in ammonical solution containing ethylenediaminetetraacetic acid as masking agent under atmosphere. The interfering elements are gold and platinum. The milligram amount of silver can be determined by the proposed method within an error ${\pm}3{\%}$.

• Journal of Korea Water Resources Association
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• v.30 no.5
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• pp.441-447
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• 1997

Rainfall observation using rain gage network or satellites includes the sampling error depending on the observation methods or plans. For example, the sampling using rain gages is continuous in time but discontinuous in space, which is nothing but the source of the sampling error. The sampling using satellites is the reverse case that continuous in space and discontinuous in time. The sampling error may be quantified by use of the temporal-spatial characteristics of rainfall and the sampling design. One of recent works on this problem was done by North and Nakamoto (1989), who derived a formulation for estimating the sampling error based on the temporal-spatial rainfall spectrum and the design scheme. The formula enables us to design an optimal rain gage network or a satellite operation plan providing the statistical characteristics of rainfall. In this paper the formula is reviewed and applied for the sampling error problems using several multi-dimensional precipitation models. The results show the limitation of the formulation, which cannot distinguish the model difference in case the model parameters can reproduce similar second order statistics of rainfall. The limitation can be improved by developing a new way to consider the higher order statistics, and eventually the probability density function (PDF) of rainfall.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.663-668
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• 2023

Recently it is very important to collect information such as enemy positions and facilities. To this end, unmanned aerial vehicles such as multicopters have been actively developed, and various mission equipment mounted on unmanned aerial vehicles have also been developed. The coordinate-oriented algorithm refers to an algorithm that calculates a gaze angle so that the mission equipment can fix the gaze at a desired coordinate or position. Flight data and GPS data were collected and simulated using Matlab for coordinate-oriented algorithms. In the simulation using only the coordinate data, the average Pan axis angle was about 0.42°, the Tilt axis was 0.003°~0.43°, and the relatively wide error was about 0.15° on average. As a result of converting this into the distance in the NE direction, the error distance in the N direction was about 2.23m on average, and the error distance in the E direction was about -1.22m on average. The simulation applying the actual flight data showed a result of about 19m@CEP. Therefore, we conducted a study on the self-error of coordinate-oriented algorithms in monitoring and information collection, which is the main task of EOTS, and confirmed that the quantitative target of 500m is satisfied with 30m@CEP, and showed that the desired coordinates can be directed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.2
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• pp.169-177
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• 2017

In this paper, classification of spall and crack faults of gear teeth is studied by applying the ensemble empirical mode decomposition(EEMD) for the gear transmission error(TE). Finite element models of the gears with the two faults are built, and TE is obtained by simulation of the gears under loaded contact. EEMD is applied to the residuals of the TE which are the difference between the normal and faulty signal. From the result, the difference of spall and crack faults are clearly identified by the intrinsic mode functions(IMF). A simple test bed is installed to illustrate the approach, which consists of motor, brake and a pair of spur gears. Two gears are employed to obtain the TE for the normal, spalled, and cracked gears, and the type of the faults are separated by the same EEMD application process. In order to quantify the results, crest factors are applied to each IMF. Characteristics of spall and crack are well represented by the crest factors of the first and the third IMF, which are used as the feature signals. The classification is carried out using the Bayes decision theory using the feature signals acquired through the experiments.