• 환경영향평가
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• 제21권4호
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• pp.593-607
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• 2012

The Ministry of Environment have started the 'National Ecosystem Survey' since 1986. It has been carried out nationwide every ten years as the largest survey project in Korea. The second one and the third one produced the GIS-based inventory of species. Three survey methods were different from each other. There were few studies for species distribution using national survey data in Korea. The purposes of this study are to test species distribution models for finding the most suitable modeling methods for the National Ecosystem Survey data and to investigate the modeling results according to survey methods and taxonominal group. Occurrence data of nine species were extracted from the National Ecosystem Survey by taxonomical group (plant, mammal, and bird). Plants are Korean winter hazel (Corylopsis coreana), Iris odaesanensis (Iris odaesanensis), and Berchemia (Berchemia berchemiaefolia). Mammals are Korean Goral (Nemorhaedus goral), Marten (Martes flavigula koreana), and Leopard cat (Felis bengalensis). Birds are Black Woodpecker (Dryocopus martius), Eagle Owl (Bubo Bubo), and Common Buzzard (Buteo buteo). Environmental variables consisted of climate, topography, soil and vegetation structure. Two modeling methods (GAM, Maxent) were tested across nine species, and predictive species maps of target species were produced. The results of this study were as follows. Firstly, Maxent showed similar 5 cross-validated AUC with GAM. Maxent is more useful model to develop than GAM because National Ecosystem Survey data has presence-only data. Therefore, Maxent is more useful species distribution model for National Ecosystem Survey data. Secondly, the modeling results between the second and third survey methods showed sometimes different because of each different surveying methods. Therefore, we need to combine two data for producing a reasonable result. Lastly, modeling result showed different predicted distribution pattern by taxonominal group. These results should be considered if we want to develop a species distribution model using the National Ecosystem Survey and apply it to a nationwide biodiversity research.

• 한국유기농업학회지
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• 제18권4호
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• pp.549-557
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• 2010

본 연구는 기능성 성분으로 알려져 있는 게르마늄을 '신고' 배나무에 처리 방법을 달리 했을 때 어떤 처리방법이 동계전정 된 가지에 게르마늄 흡수를 증가시키며 화아형성에 기여하는지에 대해서 조사하였다. 게르마늄 처리는 엽면살포, 토양 내 관주, 수간주입, 그리고 세가지 복합처리를 포함하였다. 전정 된 가지 내 게르마늄 함량은 복합처리구에서 가장 높았으며 게르마늄 처리 모두 대조구 보다 높은 함량을 보였다. 수삽된 전정가지 당 눈의 중량과 발생 된 인편의 수는 게르마늄 처리구에서 대조구보다 높은 경향을 나타냈다. 게르마늄 처리구는 개화율과 화총 당 꽃수를 증가시켰으며 저온 피해에 대해 대조구보다 유의적으로 낮은 양상을 보였다. 전체적으로 게르마늄 처리방법에 따른 수체에 나타나는 효과는 일관성이 없었다.

• 한국구조물진단유지관리공학회 논문집
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• 제7권1호
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• pp.147-156
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• 2003

In this research, multiple corrosion factors of buried environments were measured in order to establish a formula for the corrosion character of corrugated steel structures in domestic environments. By substituting corrosion factors for each predicting formula, the durable lifetime was measured, and the measured lifetime was compared with the estimated lifetime by applying existing thickness-measuring techniques. A new usage standard was proposed with these results, in order to create the conclusion below. There are known differences in the soil factors used as variables in estimating the duration caused by the seasonal effects of rainfall and temperature. Comparing the durable lifetime estimated by each predicting formula, the findings show that the California technique is conservative. This study demonstrates that the error range of the AISI technique, which is mostly used as a duration technique, is a very narrow predicting technique as compared with many other countries. Considering that there is on average, a 13% error margin in this study, a proposed safety factor of 0.87 could be used to more accurately predict the duration. The laying time in the California technique is not longer than the whole durability, and as a result, this error margin exists. It is concluded that this study on the open area has been overdue. Based on these findings, it's proposed that this error margin should be applied to the domestic environment through periodic observation, in order to establish the predicting techniques of durable lifetime.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.759-767
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• 2009

대규모 연약지반개량 설계는 압밀영향인자의 불확실성으로 대부분 신뢰성해석을 도입하여 설계를 수행하는 추세이다. 신뢰성해석은 이론습득의 어려움으로 인하여 실무 기술자들에게 범용되지 못하고 있다. Duncan(2000)이 제안한 간편하고 유용하게 사용할 수 있는 신뢰성해석 간편법과 전통적인 신뢰성해석법의 해석결과를 비교하여 간편법의 적용성을 평가하였다. 민감도분석에서는 동일한 경향을 보였으나, 파괴확률은 약 20~50%의 오차를 보이고 확률변수의 확률분포에 따른 적용성이 떨어지는 것으로 평가되었다. 신뢰성해석 간편법은 개략설계시 결정론적해석과 상호 보완적으로 적용한다면 최적설계가 이루어질 수 있을 것으로 사료된다.

• Safety and Health at Work
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• 제6권1호
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• pp.18-24
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• 2015

Background: In 2006, three farmers died at the bottom of an agricultural shallow well where the atmosphere contained only 6% oxygen. This study aimed to document the variability of levels of oxygen and selected hazardous gases in the atmosphere of wells, and to identify ambient conditions associated with the low-oxygen situation. Methods: A cross-sectional survey, conducted in June 2007 and July 2007, measured the levels of oxygen, carbon monoxide, hydrogen sulfide, and explosive gas (percentage of lower explosive limit) at different depths of the atmosphere inside 253 wells in Kamphaengphet and Phitsanulok provinces. Ambient conditions and well use by farmers were recorded. Carbon dioxide was measured in a subset of wells. Variables independently associated with low-oxygen condition (<19.5%) were identified using multivariate logistic regression. Results: One in five agricultural shallow wells had a low-oxygen status, with oxygen concentration decreasing with increasing depth within the well. The deepest-depth oxygen reading ranged from 0.0% to 20.9%. Low levels of other hazardous gases were detected in a small number of wells. The low-oxygen status was independently associated with the depth of the atmosphere column to the water surface [odds ratio (OR) = 13.5 for 8-11 m vs. <6 m], depth of water (OR = 0.17 for 3-<8 m vs. 0-1 m), well cover (OR = 3.95), time elapsed since the last rainfall (OR = 7.44 for >2 days vs. <1 day), and location of well in sandy soil (OR = 3.72). Among 11 wells tested, carbon dioxide was detected in high concentration (>25,000 ppm) in seven wells with a low oxygen level. Conclusion: Oxygen concentrations in the wells vary widely even within a small area and decrease with increasing depth.

• 한국농림기상학회지
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• 제6권3호
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• pp.149-163
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• 2004

Evapotranspiration (ET) is a critical component of the hydrologic cycle which influences economic activities as well as the natural ecosystem. While there have been numerous studies on ET estimation for homogeneous areas using point measurements of meteorological variables, monitoring of spatial ET has not been possible at landscape - or watershed - scales. We propose a site-specific application of the land surface model, which is enabled by spatially interpolated input data at the desired resolution. Gyunggi Province of South Korea was divided into a regular grid of 10 million cells with 30m spacing and hourly temperature, humidity, wind, precipitation and solar irradiance were estimated for each grid cell by spatial interpolation of synoptic weather data. Topoclimatology models were used to accommodate effects of topography in a spatial interpolation procedure, including cold air drainage on nocturnal temperature and solar irradiance on daytime temperature. Satellite remote sensing data were used to classify the vegetation type of each grid cell, and corresponding spatial attributes including soil texture, canopy structure, and phenological features were identified. All data were fed into a standalone version of SiB2(Simple Biosphere Model 2) to simulate latent heat flux at each grid cell. A computer program was written for data management in the cell - based SiB2 operation such as extracting input data for SiB2 from grid matrices and recombining the output data back to the grid format. ET estimates at selected grid cells were validated against the actual measurement of latent heat fluxes by eddy covariance measurement. We applied this system to obtain the spatial ET of the study area on a continuous basis for the 2001-2003 period. The results showed a strong feasibility of using spatial - data driven land surface models for operational monitoring of regional ET.

• 한국구조물진단유지관리공학회 논문집
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• 제11권3호
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• pp.185-191
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• 2007

본 연구에서는 주거용 무량판구조의 내진성능을 개선하기 위한 면진적용 가능성을 평가하였으며, 시간이력 해석을 위한 지진기록 사용에 대한 문제점을 제시하였다. 면진층 강성 및 주기 평가 및 포락해석법을 적용하여 면진전 비틀림 모드가 강한 구조물을 면진시스템 적용으로 내진성능을 개선하였다. 지진기록 사용 및 크기 조절효과의 적정성을 평가하기 위하여 DBE, MCE, ASCE 7-05의 1.4DBE 의해 크기를 조정한 시간이력 해석결과를 비교한 결과, 구조물의 지반조건과 유사한 조건에서 관측된 지진기록 및 지진기록의 응답이 설계규준 응답스펙트럼의 평균${\pm}$표준편차 범위 안에 있는 기록을 사용하는 것이 적절한 것으로 판단된다.

• 한국환경생태학회지
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• 제4권1호
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• pp.33-43
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• 1990

속리산국립공원 법주사지역의 삼림군집을 대상으로 TWINSPAN에 의한 classification 및 DCA의 ordination 기법을 이용하여 식물군집구조를 밝히고 천이계열을 추정하기 위하여 70개 조사구(1조사구당 500$m^2$)를 설치하였다. TWINSPAN에 의한 classification 분석에서 6개의 군집으로 분리되어 소나무 군집, 신갈나무-소나무 군집, 졸참나무-신갈나무 군집, 신갈나무 군집, 서어나무-졸참나무 군집, 졸참나무 군집으로 나뉘었고, 분리환경인자는 해발 고와 토양습도였다. 본 연구에서는 DCA기법이 TWINSPAN보다 효율성이 더 좋았다. 천이계열은 교목상층에서는 소나무, 팥배나무$\longrightarrow$졸참나무$\longrightarrow$서어나무와 소나무, 쇠물푸래나무$\longrightarrow$신갈나무이었고, 교목하층 및 관목층에서는 참싸리, 개옻나무. 산초나무$\longrightarrow$철쭉, 참개암나무, 생강나무, 함박꽃나무$\longrightarrow$참회나무로 추정되었다. 산화발생에 의해서 식물군집의 종다양성은 매우 감소하였고, 참나무류의 상대우점치는 증가하였다.

• 한국지반공학회논문집
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• 제27권11호
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• pp.55-69
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• 2011

다양한 지반공학적 문제들에서 불포화 상태의 중요성이 강조되면서, 불포화 지반의 열-수리-역학적 현상들에 대한 거동특성을 모사하기 위한 역학적 구성모델 개발이 진행되고 있다. 본 연구에서는 Bishop의 유효응력 정의에 근거한 불포화 지반의 역학적 탄소성 구성모델을 제시하였다. 유효응력에 근거한 구성관계는 유효응력과 온도를 주 변수로 증분 형식으로 표현되었으며, 이를 이용하여 응력 갱신과 강성 텐서를 산정하였다. 개발된 구성모델을 이용하여 THM 현상을 포함하는 불포화토의 1차원 거동, 불포화토의 삼축 압축시험, 그리고 고준위 방사성폐기물 시설의 완충재의 거동 특성에 관한 예제 해석을 수행하여 해의 안정성과 구성모델의 적용성에 대하여 논의하였다. 수치해석결과는 개발된 역학적 구성모델이 THM 현상의 매우 복잡한 거동을 효과적으로 모사할 수 있었으며, 일반적인 불포화토의 거동 해석뿐만 아니라 다양한 환경 조건하에서의 THM 거동 해석에 적용이 가능할 것으로 판단된다.

• 한국환경복원기술학회지
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• 제23권1호
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• pp.49-62
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• 2020

This study was conducted as a basic study to develop the HSI(Habitat Suitability Index) model of Pelophylax chosenicus based on the research on the ecological and habitat status of Pelophylax chosenicus and the literature research on the HSI model. The habitat variables of Pelophylax chosenicus are the altitude of the spawning pond, the habitat area, the distance from wetland, the soil(aptitude grade for paddy field), the place for eating such as paddy field and wetlands(land cover) and the distance from Predator(Lithobates catesbeianus) distribution area. Based on the existing literature of Pelophylax chosenicus, the results of field surveys and expert opinions, the SI(Suitability Index) model and HSI model were developed and applied to the site to examine the applicability of the HSI model. As a result of application, SI 4 and SI 5 with varying SI values seem to have a major influence on the HSI. In addition, it is considered that the HSI model is an arithmetic mean of SI models, which has a major impact on HSI. The HSI model can be an important basis for the habitat evaluation and restoration model of Pelophylax chosenicus. In particular, it is highly applicable to the selection and evaluation of alternative habitats for Pelophylax chosenicus.