• 환경영향평가
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• 제29권4호
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• pp.272-285
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• 2020

본 연구에서는 3차원 기상 및 대기질 모델의 입출력 자료를 평가하는 데 필요한 통계 검증지표를 선별하고, 선정된 검증지표의 기준치를 조사하여 그 결과를 요약하였다. 여러 국내외 문헌과 최근 논문 검토를 통해 최종 선정된 통계 검증지표는 MB (Mean Bias), ME (Mean Error), MNB (Mean Normalized Bias Error), MNE (Mean Absolute Gross Error), RMSE (Root Mean Square Error), IOA (Index of Agreement), R (Correlation Coefficient), FE (Fractional Error), FB (Fractional Bias)로 총 9가지이며, 국내외 문헌을 통해 그 기준치를 확인하였다. 그 결과, 기상모델의 경우 대부분 MB와 ME가 주요 지표로 사용되어 왔고, 대기질 모델 결과는 NMB와 NME 지표가 주로 사용되었으며, 그 기준치의 차이를 분석하였다. 아울러 이들 통계 검증지표값을 이용하여 모델 예측 결과를 효과적으로 비교하기 위한 표출 도식으로 축구 도식, 테일러 도식, Q-Q (Quantile-Quantile) 도식의 장단점을 분석하였다. 나아가 본 연구 결과를 기반으로 우리나라의 산악지역의 특수성 등이 잘 고려된 통계 검증지표의 기준치 설정 등의 추가연구가 효과적으로 진행될 수 있기를 기대한다.

• 암석학회지
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• 제20권1호
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• pp.1-21
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• 2011

한반도 남동부에 자리잡고 있는 제3기 분지 중에서 장기, 어일 분지에 대한 암석학적인 기재 및 지화학적 자료를 바탕으로 과거 조구조적 위치와 현무암질암을 생성한 기원마그마의 특성을 고찰하였다. 어일 현무암질 암내 사장석 반정에서는 여러 형태의 누대구조와 융식구조 및 체구조가 나타나며 반정의 성분변화에서 핵부분은 $An_{63.46-98.38}\;Ab_{1.62-32.96}\;Or_{0-3.58}$의 영역 (anorthite-labradorite)에 도시되고, 최외각은 $An_{40.89-82.44}\;Ab_{17.10-46.43}\;Or_{0-12.68}$의 영역 (bytownite-labradorite)에 해당한다. 주원소 분석결과, 이들 암석들은 현무암질 안산암 영역에 점시되며, 비알칼리암(sub-alkaline)계열에 해당한다. TAS도에 현무암과 현무암질 안산암의 영역에 점시되며, 비알칼리암(sub-alkaline)계열에 해당한다. $SiO_2$ 값이 커질수록 $Na_2O$와 $K_2O$는 증가하며 $TiO_2$, $FeO^*$, CaO, MgO, $P_2O_5$는 감소하는 경향을 보여준다. $K_2O-SiO_2$도표에서도 중-K계열의 칼크알칼리계열에 해당함을 보여준다. 미량원소 및 희토류 원소의 경향은 분화가 진행됨에 따라 Co, Ni, V, Zn, Sc 등과 같은 호정성 원소는 감소하고, Ba, Rb 등의 불호정성 원소들은 증가하는 특징을 보여준다. 0.81~1.00의 $Eu/Eu^*$값은 사장석 분별작용이 일부 암석에서는 거의 일어나지 않았거나 사장석의 분별이 약했다는 것을 시사한다. 동위원소 분석결과 $^{87}Sr/^{86}Sr$은 0.704090~0.704717, $^{143}Nd/^{144}Nd$은 0.512705~0.512822로서 Nd에 비해 Sr의 변화폭이 크지만 0.0007 내외의 변화폭을 보인다. 이러한 동위원소의 변화는 연구지역 현무암이 해양판의 섭입에 의해 결핍맨틀과 부화맨틀이 혼합되어 형성된 마그마에 기원함을 추정할 수 있게 한다. 동위원소비는 맨틀 경향에 잘 따르며 결핍맨틀(DMM)과 부화맨틀(EM)의 섞임 현상에 의한 맨틀조성을 갖는 마그마에 기원을 두고 있다.

• 소성∙가공
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• 제28권6호
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• pp.368-374
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• 2019

The past recent years have seen an increasing use of high-strength steel sheets in the automotive industry. However, the formability and damage prediction of these materials requires accurate acquisition of necking and fracture strains. Digital image correlation (DIC) is used to accurately capture the necking and fracture strains during testing. The fact that single time points of capturing vary with frame rate makes the need for an investigation necessary. For the high-strength steel DP980, the frame-rate dependences of the final necking and fracture strains values are analyzed here. To eliminate the influence of gauge length, the strains were measured locally by DIC. Results for three specimen shapes obtained with frame rates of 1 and 900 fps (frames per second) were considered and based on them, triaxiality failure diagrams (TFD) are established. It was observed that after diffuse necking, the deformation path departed from the initially linear one, and the stress triaxiality grew with ongoing deformation. It was further revealed that the frame rate-dependence of the necking strain was rather low (< 2%), whereas the fracture strain could be underestimated by up to 8% when the lower frame rate of 1 fps was used (compared with 900 fps). In this study, this issue is investigated while taking into consideration the three different triaxialities. These results demonstrate the importance of choosing an appropriate frame rate for the determination of necking and fracture strains in particular.

• 한국지하수토양환경학회지:지하수토양환경
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• 제29권3호
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• pp.23-36
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• 2024

Miryang City, the study area, has a water supply rate of 87.4%, which is 12% lower than the national water supply rate of 99.4%, but has a high dependence on groundwater due to the high ratio of farms. In agricultural areas, contamination becomes relatively more critical, requiring significant attention to the management and conservation of groundwater resources. This study aims at estimate groundwater vulnerability of Miryang City using the DRASTIC index map, Piper diagram, and water quality data to correlated with the DRASTIC index. The results from DRASTIC map were divided into five classes: very high, high, moderate, low, and very low. The areas in central and southern part of study area, which are characterize by a very high index with [Ca-Cl] and [Na-Cl] water types, covering a large alluvium with the Miryang River and Nakdonggang River. In addition, a correlation analysis between groundwater quality parameters and the DRASTIC index was carried out. Chloride, sodium, and sulfate ions showed a weak relationship with DRASTIC index, with correlation coefficient was 0.507, 0.487 and 0.344, respectively. These results suggest that aquifer media, soil media, hydraulic conductivity, and chloride ion are important factors for groundwater vulnerability.

• 한국환경과학회지
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• 제21권8호
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• pp.965-975
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• 2012

Loading of NPS pollutant was valued through simulation by using BASINS/HSPF model which can simulate runoff volume in rainfall by time. For the verification of the model, it was analyzed the scatter diagram of the simulation value and measure value of water quality and runoff volume in Dongcheon estuary. Using the built model, a study on the time-variant characteristics of runoff and water quality was simulated by being classified into four cases. The result showed the simulation value was nearly same as that of the measured runoff. In the result of fit level test for measured value and simulated value, correlation of runoff volume was computed high by average 0.86 and in the water quality items, fit level of simulation and measurements was high by BOD 0.82, T-N 0.85 and T-P 0.79.

• 설비공학논문집
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• 제8권4호
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• pp.527-536
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• 1996

Convective nucleate boiling and burnout heat flux have been studied on a flat, downward facing, constant heat flux surface cooled by an impinging water jet. The tests are progressed from low, nonboiling power to high, burnout heat flux power. The jet velocity and the subcooling do not affect the nucleate boiling curve of $q{\sim}{\Delta}T_{sat}$ diagram, but the supplementary water height affects the curve. For the case of dimensionless height of supplementary water S/D=1, the boiling curve shift to the heigher heat flux than that of S/D=0 or S/D=2. Burnout heat flux is enhanced with increasing jet velocity and subcooling. Also. by using the supplementary water(S/D=1 or S/D=2), burnout heat flux is larger than that of the simple water jet(S/D=0). A generalized correlation for the burnout heat flux data in the present boiling system with an impinging water jet is successfully evolved.

• 천문학회보
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• 제38권2호
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• pp.64.1-64.1
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• 2013

High energy photons and mechanical energy produced by the process of star formation result in copious FIR molecular and atomic lines, which are important coolants of the system. Photons thermally or mechanically induced could dissociate water in the dense envelope to change relative abundances among the species O, OH, and H2O. Here we analyze OH emission lines toward embedded young stellar objects (YSOs) observed as part of the Herschel open time key program, 'Dust, Ice, and Gas In Time (DIGIT)' in order to study the physical conditions of associated gas and the energy budget loaded on the OH line emission. According to our analysis of the Herschel/PACS spectra, OH emission peaks at the central spaxel in most of sources, but several sources show spatially extended emission structures. In the extended emission sources, the distribution of OH emission is correlated with that of [OI] emission and extended along the outflow directions. Considering the diversity of source properties, ratios between detected OH lines are relatively constant among sources. In addition, each OH line has strong correlation with bolometric luminosity. For detail analyses with rotation diagram and non-LTE LVG model, we present the results from GSS30-IRS1 and Elias29.

• Steel and Composite Structures
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• 제12권5호
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• pp.379-393
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• 2012

Many steel bridge infrastructures in the world are getting older, and a large number of these structures are in need of maintenance, rehabilitation or replacement. Most of them are subjected to corrosion due to exposure to aggressive environmental conditions and inadequate maintenance, causing reduction of their carrying capacities. In order to have an adequate bridge management, it is of paramount importance to develop an efficient, accurate and rapid condition assessment method which can be used to make reliable decisions affecting the cost and safety. Therefore, a simple and accurate method of calculating remaining yield and tensile strength by using a concept of representative effective thickness with correlation of initial thickness and maximum corroded depth is proposed in this study, based on the results of many tensile coupon tests of corroded plates obtained from a steel plate girder with severe corrosion, used for about 100 years. Furthermore, a strength reduction diagram which will be very useful for bridge inspection engineers to make rational decisions about the maintenance management of aged steel bridge infrastructures is presented.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2003년도 하계학술연구발표회 및 한.일 공동심포지엄
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• pp.150-151
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• 2003

In the past years, a giant magnetoresistance (GMR) effect found in perovskite-like structured materials has attracted considerable attention among scientists and manufacturers, since, a practical point of view, the capacity of producing magnetic and sensing sensors. In a stream of this interest, further efforts to understand the underlying mechanism that leads to the GMR effect relative to the correlation between transport and magnetic properties, have been extensively devoted. In these cases, spin-glass-like behaviors are ascribed to the frustration of random competing exchange interactions, namely the ferromagnetic double-exchange interaction between Co$\^$3+/ (or Mn$\^$3+/) and Co$\^$4+/(or Mn$\^$4+/) and the antiferromagnetic one like spins. Noticeably, the distinction of spin-glass region from cluster-glass one, involved in the remarkable changes in transport and magnetic properties at a critical value of doping concentration, was observed. Magnetic anomalies in zero-field-cooled (ZFC) magnetization as well as ac magnetic susceptibility below Curie temperature T$\sub$c/ and the charge/orbital fluctuation were also realized. In this work, we present a study of magnetic properties of a deficient manganese perovskites system of La$\sub$0.6/Sr$\sub$x/MnTi$\sub$y/O$_3$, and particularly provide its new magnetic phase diagram.

• 천문학회보
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• 제35권1호
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• pp.51.2-51.2
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• 2010

We have carried out an extensive statistical analysis based on the results of simultaneous observations of SiO and $H_2O$ masers toward 166 known SiO and $H_2O$ maser sources using KVN_Yonsei radio telescope (Kim et al.2010, ApJS submitted). We investigate the distributions of the mean velocities and the intensity ratios between SiO and $H_2O$ maser emission including those between SiO v=1 and v=2,J=1-0 transitions according to type of evolved stars. We also investigate mutual relations between SiO and $H_2O$ maser properties(total flux densities and velocity structures etc.) according to stellar pulsation phases. Most of SiO masers appear around the stellar velocity (80 % within ${\pm}5km\;s^{-1}$), while $H_2O$ masers show a different characteristic compared with SiO masers (69% within ${\pm}5km\;s^{-1}$). In addition, we investigate a correlation between $SiO/H_2O$ maser emission and AKARIFIS flux density as well as the AKARI color characteristics of SiO and $H_2O$ observational results in the AKARIFIS two-color diagram.