• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.367-367
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• 2012

기후변화로 인해 기온, 강수량, 습도 등의 기후를 예측하고 변화하는 환경에 적응해가며 생활하고 있다. 또한 여러 가지 외부적인 요인들의 영향을 받아 상수도 시설에서의 에너지 사용량도 영향을 많이 받는다. 하지만 이러한 상수도 시설의 사용량 변화로 인해 상수도 수요량의 변화량을 예측하는데 있어서 국내 연구 및 방법이 많이 부족한 상황이다. 이에 본 연구에서는 다중스케일을 기반으로 하는 비선형 예측 모형을 개발하고자 한다. 다중스케일 분석에서도 가장 우수한 분해 능력을 가지는 Wavelet Transform을 적용하여 시계열을 분해한 후 패턴인식 기반의 비선형 예측모형인 Support Vector Machine(SVM)을 적용하였다. 상수도 수요량의 예측 과정은 다음과 같다. 첫째, 상수도 수요량 자료를 Wavelet Transform 기법을 통하여 단순화 시킨다. 둘째, Global Wavelet Spectrum을 통하여 통계적으로 의미 있는 성분만을 추출하고 이를 해석 대상으로 한다. 셋째, 특정 주기를 갖는 유의한 독립성분들에 대해서 최적 지체시간을 결정한 후 SVM모형을 통해 예측 모형을 구축한다. 넷째, 나머지 성분에 대해서도 SVM 모형을 적용하여 예측을 실시한 후 앞서 예측된 성분과 모두 결합하여 최종적으로 예측시계열을 구성한다.

• Fire Science and Engineering
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• v.23 no.3
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• pp.103-109
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• 2009

The thermal degradation of concrete results mainly from two mechanisms. The first one is related to phase transformations of constituents at different temperatures. The initial constituents transform to other phases due to elevated temperature. The second mechanism is related to the temperature sensitivity of the mechanical properties of the constituents in concrete. Therefore, the degradation of concrete under high temperatures must be studied from both mechanical and chemical points of view. This study was performed as a basic study to propose the material models of concrete exposed to high temperatures considering above two mechanisms. This study presents a prediction model on the porosity of hardened cement paste considering phase changes according to temperature increase.

• Geophysics and Geophysical Exploration
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• v.14 no.1
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• pp.1-6
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• 2011

As a check on calibration and drift in each discrete sub-system of a commercial frequency-domain airborne electromagnetic system, we aim to use causality constraints alone to predict in-phase from wide-band quadrature data. There are several possible applications of the prediction of in-phase response from quadrature data including: (1) quality control on base level drift, calibration and phase checks; (2) prediction and validation of noise levels in in-phase from quadrature measurements and vice versa and in future; and (3) interpolation and extrapolation of sparsely sampled data enforcing causality and better frequency-domain-time-domain transformations. In practice, using tests on both synthetic and measured Resolve helicopter-borne electromagnetic frequency domain data, in-phase data points could be predicted using a scaled Hilbert transform with a standard deviation between 40 and 80 ppm. However, relative differences between base levels between flight could be resolved to better than 1 ppm, which allows an independent quality control check on the accuracy of drift corrections.

• Food Science and Preservation
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• v.17 no.1
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• pp.151-159
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• 2010

Changes in volatile organic compounds were investigated during storage after electron beam irradiation. Grapes were irradiated at 0.25, 0.5, 0.75, and 1.0 kGy and stored for 1 month at $4^{\circ}C$. Butanol, hexanal, [E]-2-hexenal, hexanol, and 3-methyl-butanol were the major volatile organic compounds of grapes. The types of volatiles in irradiated grapes were similar to those of non-irradiated samples but concentration differed among treatments. Some volatile compounds decreased during storage, whereas others, especially the esters, increased. Concentration of most volatile compounds were higher in pre-stored grapes than in post-stored fruit (thus, during the 30 days after irradiation by e-beam). Consequently, concentration of volatile organic compounds either increased or decreased after e-beam irradiation but these changes did not correlate with irradiation dose.

• Journal of Korea Water Resources Association
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• v.42 no.12
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• pp.1125-1133
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• 2009

Evanescent modes which are the other solutions of the Laplace equation for the linear dispersion equation may affect the wave transformation especially when a water depth varies abruptly. In this study, the effects of evanescent modes for a three-dimensional depression of seabed are investigated by using the eigenfunction expansion method. A convergence test is first carried out by changing numbers of domains and evanescent modes. The wave transformation for various depressions of seabed is then calculated under condition that the solution of the eigenfunction expansion method is converged.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.785-1-789-5
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• 2008

최근 수자원 분야에서는 대상유역의 최종출구점 뿐만 아니라 유역내 수문성분의 시 공간적인 분포특성에 관한 관심이 높아지고 있다. 이러한 분석을 위해 GIS와 연계된 물리적 기반의 분포형 수문모형이 널리 사용되고 있다. 하지만, 분포형 모형의 적용에 있어 문제로 제기되고 있는 격자크기에 대한 명확한 해법은 제시되지 못하고 있는 실정이다. 본 연구에서는 DEM 해상도(격자크기)에 따른 지형인자 및 수문성분의 변화를 검토하였다. 이를 위해 지형인자 도출에서 수문성분 분석까지 가능한 SWAT-K 모형을 횡성댐 상류유역에 적용하였다. 결과를 검토해보면, DEM 해상도가 낮아질수록, 최저고도는 증가, 최고고도는 감소, 따라서 평균고도는 다소 증가하는 경향을 보였다. 대상유역의 지형인자에 관계된 유역면적의 경우에는 해상도가 낮아질수록 다소 증가하였으며, 소유역별 유역평균경사의 경우에는 크게 감소하였다. 하도 지형인자의 경우, 해상도가 낮아질수록 주하도 길이는 감소, 주하도 경사는 반대로 증가하였다. 마지막으로 수문성분의 경우, DEM 해상도가 낮아질수록 유역 전체유출량은 다소 감소하였으며, 반대로 증발산량은 다소 증가하는 경향을 보였다. 유출성분을 세분하여 검토해보면, DEM 해상도가 낮아질수록 중간유출, 지하수유출의 경우 각각 크게 감소, 증가하는 경향을 보였다. 이는 DEM 해상도가 낮아질수록 유역경사가 완만해져 중간유출이 지하수유출로 유입되는 현상으로 파악된다.

• Economic and Environmental Geology
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• v.26 no.3
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• pp.363-370
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• 1993

Various sizes of dolerite sills occur in the Mungyong area, one of well-exposed areas in Okchon belt. All of previous geochemical studies concluded that chemical variations of basic rocks, so-called Sangnae-ri amphibolite, result from the fractional crystallization. The second sill, which is a well differentiated one in the Sangnae-ri area, displays systematic compositional variation associated with gradual change of grain size in vertical sections. In order to clarify the chemical variation in the sill, whether chemical composition of each part of the sill is appropriately derived from the original liquid (represented by the average composition) by addition or subtraction of initial phenocystic minerals are tested(Iwamori program, 1989). According to the calculation, it is shown that major vertical chemical variation of the sill resulted from the accumulation of phenocrysts(olivine, clinopyrxoene, plagioclase, titanomagnetite) which already existed at the time of emplacement or formed just after the emplacement.

• Analytical Science and Technology
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• v.25 no.1
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• pp.50-59
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• 2012

In this study, the effect of humidity change on DNPH cartridge sampling efficiency for carbonyl compounds (CCs) has been investigated. For this analysis, gaseous standard of 6 different CCs (formaldehyde (FA), acetaldehyde (AA), propionaldehyde (PA), butyraldehyde (BA), isovaleraldehyde (IA), and valeraldehyde (VA)) was calibrated after derivatization with three types of DNPH cartridge products. Their calibration results derived at RH values between 0 and 80% were then compared against liquid phase standards. If the results of our analysis are compared by the RH values between 20 and 80%, the effect of RH can be distinguished between light and heavy CCs. For lighter CCs (like FA and AA), there was no significant change. However, for the ones heavier than PA, there was fairly noticeable increase in relative recovery ratio in RH value between 20 and 80%. Such patterns are seen consistently from all three DNPH products tested for comparison. The results of our analysis suggest that proper correction for RH change may be needed for heavier CCs by the cartridge method.

• Journal of Sensor Science and Technology
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• v.10 no.6
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• pp.273-278
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• 2001

Absorption spectra of blood components have been measured for the purpose of predicting the total hemoglobin concentration. We obtained absorption spectra of major blood components from the visible to near-infrared of $400{\sim}2500nm$ region. In the near-infrared, water is the main absorbing constituent. The amount of water in the sample cell varies depending on the volume of solute concentration(water displacement). We acquired water-compensated spectra by considering the variation of water volume depending on the variation of analyze concentration. Those spectra show inherent absorption peaks of analyzes and linearity with respect to concentration. We selected wavelengths for non-invasive measurement of hemoglobin concentration considering the scattering effect of tissue and the interference of other blood components.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.132-134
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• 2003

직물에 부직포 심지를 부착하면, 각각 단독으로 있을 때와는 다른 새로운 특성을 나타내게 되고, 그러한 복합재료의 역학적 성질들을 그것의 구성성분들의 성질들로부터 예견하려는 시도가 많이 행해지고 있다. 이에 대해서는 복합재료와 구성성분들의 역학적 성질들 비교[1,2]에서부터 구성성분들의 역학적 성질들의 합에 가중치를 적용해서 구성성분들과 복합재료의 역학적 성질들의 상관관계를 구하려는 노력[3,4,5], 구성성분들 뿐만 아니라 접착제의 상태가 최종 복합재료의 역학적 성질에 미치는 영향에 대한 연구[6,7]까지 다양한 관점에서 연구가 행해지고 있다. (중략)