• 제목/요약/키워드: Residual Demand Elasticity Model

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Market Power of Genetically Modified Soybeans Traded Between the United States and Korea

  • Son, Eun-Ae;Lim, Song Soo
    • Journal of Korea Trade
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    • 제23권6호
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    • pp.131-144
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    • 2019
  • Purpose - The purpose of this study was to investigate market power of soybeans exported by the United States to Korea. Particularly, this paper considered dichotomous characteristics of genetically modified (GM) soybeans and non-GM soybeans and conducted empirical analysis of these two segregated soybean markets to understand key tenets of market power in international soybean trade. Design/methodology - The difference in market power between GM and non-GM soybeans was analyzed using Residual Demand Elasticity (RDE) and Residual Supply Elasticity (RSE) models over the period of 2008~2018. RDE and RSE models under an imperfect competition condition were used to estimate market margins and determine whether GM and non-GM exporters or importers exercised market power in the destination market. Findings - Empirical results suggested that the U.S. had a market power on both GM and non-GM soybean exports. GM exports had greater market power than non-GM exports (14% vs. 9%). By contrast, Korea showed an inability to grab market margin or exert market power in soybean imports. Both export supply by the U.S. and import demand by Korea were found to be more responsive to price changes of GM soybeans than to prices changes of non-GM soybeans. This might be due to a self-interested, profit-seeking strategy by the exporter and many concerned consumers regarding potential adverse effects of GMOs in the importing country. Originality/value - This paper fills the literature gap by exploiting market power in both GM and non-GM markets with explicit consideration of price correlations between GM and non-GM soybeans in Korea. A number of existing studies have provided evidence for market power broadly embedded in international commodity trade. However, studies focusing on Korean markets are limited. No study has explored the country's soybean trade. Furthermore, the majority of prior studies have almost exclusively focused on the market power from a standpoint of exporting countries without discussing importers' market structure. This paper also sought to understand potentially distinguished patterns of market power between GM and non-GM markets.

고온에 노출된 초고강도 콘크리트의 압축특성 (Compressive Properties of Ultra High Strength Concrete Exposed to High Temperature)

  • 강용학;강충현;최현국;신현준;김화중
    • 콘크리트학회논문집
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    • 제26권3호
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    • pp.377-384
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    • 2014
  • 최근의 건축 구조물이 고층화, 대형화됨에 따라 초고강도 콘크리트의 적용 및 수요가 증가하고 있는 추세이나, 화재에 대한 취약성을 가지고 있는 초고강도 콘크리트의 열적 특성에 대한 검토는 아직 충분하지 않으며 이에 대한 성능 검토 또한 요구되고 있는 실정이다. 이에 이 논문에서는 초고강도 콘크리트의 고온 재료 모델 개발에 대한 기초적 자료를 제공하기 위하여 상온에서 $800^{\circ}C$까지의 고온 가열을 받은 100 MPa급 초고강도 콘크리트를 대상으로 가열온도의 변화에 따른 잔존압축강도, 탄성계수 및 응력-변형 성상, 반복하중 시의 응력-변형 성상 등 역학적 특성 변화를 확인하였다. 또한, TG/DTA분석과 SEM 촬영으로 콘크리트의 화학 물리적 특성을 확인하고 국내 외의 기존 연구와 비교 검토하였다. 그 결과, 가열온도 $300^{\circ}C$에서 잔존압축강도 및 탄성계수의 급격한 저하를 확인하였으며, 반복하중 하에서는 가열온도 $400^{\circ}C$부터 소성거동이 발생하는 것과 함께 단일하중과 거의 동일한 경향을 보임을 확인할 수 있었다. TG/DTA 분석 및 SEM 촬영을 실시한 결과와 기존 연구를 비교 검토한 결과, 콘크리트 내부 조직의 열화와 수분 증발 및 화학반응 등으로 인하여 잔존압축강도 및 탄성계수의 저하가 일어났음을 확인할 수 있었다.