• Korean Journal of Construction Engineering and Management
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• v.15 no.2
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• pp.87-94
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• 2014

This study aims to analyze the relationship. The study applies EDF (Expected Default Frequency) as a variable that indicates management status of a construction company. To analyze changes in business structure of construction companies, the study refers to the amounts of domestic and overseas project orders as variables. The data was retrieved from TS2000 established by Korea Listed Companies Association (KLCA), Statistics Korea and International Contractors Association of Korea. The analysis period is between first quarter of 2001 and fourth quarter of 2010. The analysis results showed that as more domestic and overseas orders rolled in for domestic companies, their business conditions improved as the hypothesis suggested. However, the level of improvement varied. Further, when construction companies' business slowed down, the proportion of overseas projects tended to rise, while the ratio of domestic business decreased.

• International Area Studies Review
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• v.21 no.4
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• pp.19-39
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• 2017

The purpose of this paper is to investigate the impact of terms of trade and its volatility on real GDP and inflation. I estimate the linear and dynamic panel model including variables such as real GDP, inflation, terms of trade, capital stock, employment and education. The sample countries consist of OECD 26 countries and panel data ranges from 1990 to 2015. The empirical results show that terms of trade and its volatility do not affect the real GDP significantly. Even if the terms of trade has a negative relationship with real GDP, the magnitude of the estimated coefficients was very small. This result seems to be related with the industry structure and domestic demand structure of the member countries. On the other hand, terms of trade and its volatility have the significant impact on inflation. When the terms of trade and its volatility increase, the inflation increases.

• Korean Journal of Ecology and Environment
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• v.55 no.4
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• pp.259-273
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• 2022

Interactions between species in a community are very complex, and they are visualized and analyzed through a food web in simple way. Food web is a network of species connected by trophic links showing energy flow from prey to predator. Various models were developed to characterize the food web in ecosystems. In this study, we classified food web models to static models such as Ecopath and dynamic models such as AQUATOX. We presented characteristics of several different types of food web models in each category, and reviewed their applications used in aquatic ecosystems. Finally, we presented issues to be considered to develop food web models.

• Journal of the Korean Regional Science Association
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• v.39 no.4
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• pp.73-90
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• 2023

This research examines the impact of robotics integration on job dynamics in the U.S. manufacturing sector, adding to the critical dialogue on technological evolution and the future of jobs. Anchored in the task-model framework, the study hypothesizes that robotic integration exerts differential influences on diverse occupational clusters, each identified by their unique task-specific attributes. An in-depth examination was undertaken to elucidate the interplay between robotic integration and the occupation clusters. Employing a multilevel growth curve model, our empirical investigation tracked employment dynamics from 2012 to 2022 across 52 U.S. regions, covering 307 manufacturing occupations. The findings suggest a pronounced job decline within occupations necessitating manual dexterity. Nonetheless, the evidence does not conclusively support that the extent of robotics integration exacerbates this trend. These findings imply that the employment shifts in the U.S. manufacturing sector are predominantly driven by long-standing trends of deindustrialization and functional specialization, rather than by the recent diffusion of robotic technologies.

• The Korean Journal of Ecology
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• v.28 no.5
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• pp.287-293
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• 2005

This study was conducted to evaluate the effect of the conventional pesticide application system on the rice spider community based on the quantitative investigation of arthropod community in the rice fields in Saran area, Hwasung-si, Kyeonggi-do from 1996 to 1998. Spiders were the highest dominant group comprising over 90% of all natural enemies in their density, and showed very stable yearly occurrence. In these fiekds the mean density of spiders was about 10 individuals/$0.25m^2$ during the rice growing season, and three families including Lycosidae, Tetragnathidae and Linyphiidae were very abundant. The colonization of spiders occurred in early season and they showed rapid density increase in mid-season. They maintained the highest density to the late season and their density decreased at harvest season. In the years of the low rice pest occurrence, the disturbance effect on spider community by pesticides were less. Two dominant species, Pirata subpiraticus and Pachygnatha clerki, had different population dynamics; Pirata subpiraticus showed the rapid density increase in the mid-July, and most of them remained immature stages, however, in the case of Pachygnaths clerki population, they rapidly increased in the late August and most of them remained adult stage during the late growing season.

• Journal of Veterinary Clinics
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• v.24 no.3
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• pp.308-311
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• 2007

A study on the oral bioavailability and pharmacokinetics of an anticoccidal agent, toltrazuril, was conducted in broilers following a single oral doses of 10 mg/kg body weight (BW) or 40 mg/kg BW. The concentrations of toltrazuril in plasma were determined by a high-performance liquid chromatography/mass spectrometry. Plasma concentration-time data after single oral administration were analyzed by a non-compartmental analysis. Toltrazuril was very well-absorbed through the gastrointestinal tract with $C_{max}$ of $18.04{\pm}5.80{\mu}g/mL$ and $47.15{\pm}9.40{\mu]g/mL$ at $4.33{\pm}1.51h$ and $3.67{\pm}1.15h$ after oral dose of 10 mg/kg and 40 mg/kg in broilers, respectively. A comparison between 10 mg/kg and 40 mg/kg dose groups showed that $t_{max}$ were similar while $C_{max}$ and area under curve (AUC) increased with increasing dose.

• Korean Journal of Environment and Ecology
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• v.33 no.5
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• pp.565-577
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• 2019

The purpose of this study was to understand the factors influencing the decline and the patterns of changes in Abies nephrolepis populations on Mt. Seorak. We installed permanent quadrats in the areas of the Gwittagicheongbong (peak), Gwanmoneungseon (ridge), and the Seorak Falls and have monitored the community structure, population dynamics, radial growth, and vitality in the quadrats since 2009. Excluding the Seorak Falls, the three research sites showed a three-layer structure in which the low-tree layer forms the canopy. Major tree species were Khingan fir, Korean arborvitae, Mongolian oak, Erman's birch, and Korean maple. The significance of Khingan fir in Seorak Falls decreased from 45.3% in 2009 to 36.8% in 2018. The number of shoots ($DBH{\geq}5cm$) was highest at 1,800 individuals/ha and 1,700 individuals/ha at the Gwittagicheongbong 2 and the Gwanmoneungseon, respectively. The mortality rates over the past 10 years were very high, at 38.3% and 35.3%, respectively, in the Gwittagicheongbong 1 and Seorak Falls. The most stable inverse J-shaped distribution in the Gwittagicheongbong 1 area was shown in the size-frequency distribution of the Khingan fir populations. The average annual ring growth of the Khingan fir was 0.96 ~ 1.73 mm/year, and the ring growth tended to decrease in the areas of Gwittagicheongbong 1, Gwanmoneungseon, and Seorak Falls, where the vitality was low. If the monitoring process continues, it will be possible to obtain basic data for the conservation and management of subalpine vegetation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.139-142
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• 2007

본 연구는 RAS 계수법과 동태적 산업연관 모형을 동시에 적용하여 u-City 구축의 경제적 파급효과를 분석하였다는 점에서 통상적인 산업연관분석과 차별성을 지닌다. 한국은행이 가장 최근 발표한 산업연관표는 2000년도 자료이다. 본 연구는 RAS 계수법으로 알려져 있는 예측기법을 이용하여 2000년 산업연관표를 2010년 표로 연장시켜 u-City 산업의 경제적 파급효과를 분석한다. 한편 산업연관분석에 통상적으로 사용되고 있는 모형은 정태적 분석모형인 기본 산업연관 모형이지만, 본 연구에서는 동태적 산업연관 모형을 적용하여 u-City 산업의 경제적 파급효과를 동태적으로 분석하였다. u-City 구축에 따른 총 생산파급효과는 약 3.3배로 추정되었으며, u-City 산업은 전방연쇄효과는 매우 높지만 후방연쇄효과는 그다지 높지 않은 것으로 나타났다.

• Korean Journal of Environmental Biology
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• v.20 no.4
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• pp.287-293
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• 2002

Natural forest stand plays a very important role to understand the forest ecosystem in Korea, in which there is no ancient forests aye left. Several old growth Korean fir stands were studied to determine their naturalness. Internationally accept-ed criteria for virgin or natural forests were used and the changes in several stages by stand dynamics were applied. Although the areas survey is limited in size, it was discovered that they clearly represent certain characteristics of naturalness. This study and collected data will hopefully be the starting point for the further studies for naturalness of forest in Korea in the future.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.1-1
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• 2015

최근 연구에 의하면 엘니뇨 패턴의 중심이 열대 동태평양에서 중앙태평양으로 이동하는 양상을 보이고 있는 것으로 보고되고 있으며 태평양 연안 국가를 중심으로 이에 대한 연구가 많이 진행되고 있다. 본 연구에서는 진화하는 엘니뇨패턴과 관련하여 한반도의 영향을 미치는 태풍을 중심으로 태풍의 활동특성과 그에 따른 지역별 태풍강우의 특성을 비교 분석하였다. CT/WP 엘니뇨와 관련하여 북서태평양 지역에서 발생한 태풍이 한반도에 미치는 영향을 분석하기 위하여 태풍에 의해 발생한 여름철 강우와 중호우 사상의 발생특성을 분석하였다. CT 엘니뇨해에는 한반도의 서남부 지역에서 태풍에 의한 여름철 강우가 감소하는 경향이 나타났으며, 동북부 지역에서는 증가하는 특성이 있음을 확인하였다. 또한 WP 엘니뇨 해에는 한반도 대부분 지역에서 태풍에 의한 여름철 강우가 증가하였으며, 중북부지역과 중서부 지역에서 통계적으로 유의한 증가패턴이 있는 것으로 분석되었다. 본 연구의 성과는 태풍을 고려한 지역 맞춤형 기반시설 확충 및 유역대책 수립, 수자원 확보 등에 대한 기초자료로 활용 될 수 있을 것으로 기대된다.