• 한국연초학회지
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• 제3권2호
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• pp.109-114
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• 1981

This experiment was conducted with three varieties (Hicks, Burley 21, Sohyang) and cropping systems (Improved mulching, Mulching, Non mulching) of NC 2326 to analyze growth kinetics by means of growth function involving its velocity and accelerated velocity. The basic growth data were obtained by harvest method at interval of ten days from transplanting to hundred days and analyzed by , regression equation, determinant of matrix, and differentiation. The plot of total dry weight of leaves, stalk and roots per a plant vs. time forms a sigmoid curve and its function fitted logistic satisfactorily. Tobacco plant grows at an accelerated velocity. And growth velocity, symmetric about an inflection point, is proportional to biomass attained and to the difference between biomass attained and the maximum, and to the decrease according to the biomass. Of varieties and cropping systems, the most maximum velocity was 9.58g per day per plant in mulching cultivation of NC 2326 and maximum accelerated velocity was 264mg per $day^2$ per plant in Burley 21.

• 아동학회지
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• 제30권4호
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• pp.69-85
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• 2009

The purpose of this study was to identify developmental trajectories of externalizing problems in preschoolers and to investigate dimensions of temperament and parental behaviors associated with trajectory groups. Subjects were 180 3- to 5-year-old preschoolers (96 males, 84 females) in the metropolitan area of Seoul. They were assessed three times at 5 month intervals over a one year period. Teachers reported on children's behavior problems, and parents reported on children's temperaments. Latent Growth Curve Modeling Analysis with cohort sequential design revealed externalizing behaviors gradually decreased between 3 and 6. At the 6-year-old level externalizing behaviors were associated with high novelty seeking temperament. The results were discussed in terms of the importance of longitudinal research in developmental psychopathology.

• 대한안전경영과학회지
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• 제18권4호
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• pp.39-46
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• 2016

In this paper, the relationship between energy consumption in the logistics industry and economic growth of Tumen River region from 1995 to 2014 is empirically analyzed by using the EKC model theory. The results show that there is a turning point in the Kuznets curve of carbon emission in TumenRiverregion. And it has the characteristic sof "invertedU" curve, which conforms to the environmental Kuznets curve hypothesis. Meanwhile it is stil lintherisingstage. According to the analysis results, it is proposed to set up the concept of low carbon logistics, optimize the energy structure, strengthen the information construction, and establish low-carbon development mechanism and so on.

• Nuclear Engineering and Technology
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• 제38권3호
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• pp.277-284
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• 2006

In order to ensure the structural integrity of nuclear welded structures during design life, the fatigue life has to be evaluated by fatigue analysis procedures presented in technical codes such as ASME B&PV Code Section III. However, existing fatigue analysis procedures do not explicitly consider the presence of welded joints. A new fatigue analysis procedure based on a structural stress/fracture mechanics approach has been recently developed in order to reduce conservatism by erasing uncertainty in the analysis procedure. A recent review of fatigue crack growth data under various mean loading conditions using the structural stress/fracture mechanics approach, does not consider the mean loading effect, revealed some significant discrepancies in fatigue crack growth curves according to the mean loading conditions. In this paper, we propose the use of the stress intensity factor range ${\Delta}K$ characterized with loading ratio R effects in terms of the structural stress. We demonstrate the effectiveness in characterizing fatigue crack growth and S-N behavior using the well-known data. It was identified that the S-N data under high mean loading could be consolidated in a master S-N curve for welded joints.

• 대한기계학회논문집
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• 제16권9호
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• pp.1627-1631
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• 1992

본 연구에서는 균열길이 감소현상의 처리법에 대하여 고찰하고자 하며, 내용 을 요약하면 다음과 같다. (1) 오프세트(offset)법의 배경 및 오프세트법에 의한 균열길이 감소현상의 처리 방법 을 제안하였다. (2) 실제의 균열길이의 측정과 $J_{IC}$실험해석을 통하여, 수정식과 오프세트법의 타 당성을 검토하였다.

• Journal of Information Technology Applications and Management
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• 제12권2호
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• pp.1-13
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• 2005

This paper proposes a software-reliability growth model incoporating the amount of testing effort expended during the software testing phase after developing it. The time-dependent behavior of testing effort expenditures is described by a Logistic curve. Assuming that the error detection rate to the amount of testing effort spent during the testing phase is proportional to the current error content, a software-reliability growth model is formulated by a nonhomogeneous Poisson process. Using this model the method of data analysis for software reliability measurement is developed. After defining a software reliability, This paper discusses the relations between testing time and reliability and between duration following failure fixing and reliability are studied. SRGM in several literatures has used the exponential curve, Railleigh curve or Weibull curve as an amount of testing effort during software testing phase. However, it might not be appropriate to represent the consumption curve for testing effort by one of already proposed curves in some software development environments. Therefore, this paper shows that a logistic testing-effort function can be adequately expressed as a software development/testing effort curve and that it gives a good predictive capability based on real failure data.

• Asian Journal of Business Environment
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• 제11권1호
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• pp.39-50
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• 2021

Purpose: This study seeks to establish the environmental damage theory applicable to Kenya. The analysis is based on annual data drawn from World Bank on carbon dioxide emissions (CO2e) and gross domestic product per capita (GDPPC) for Kenya spanning 1963 to 2017. Research Methodology: The study adopts explanatory research design and autoregressive distributed lag model for analysis. Results: The results revealed a coefficient of -0.017 for GDPPC and 0.004 for GDPPC squared indicating that economic growth has negative effect on CO2e in the initial stages of growth but positive effect in the high growth regime with the marginal effect being higher in the initial growth regime. The findings suggest a U-shaped relationship consistent with Brundtland Curve Hypothesis (BCH). Conclusions: The findings emphasize the need for sustainable development path that enables present generations to meet own needs without compromising the capacity of future generations to meet their own. Sustainable development may include, investment in renewable energies like wind, solar and adoption of energy efficient technologies in production and manufacturing. The study concludes that BCH is applicable to Kenya and that developing affordable and effective mechanisms to boost sustainable development implementation is necessary to decrease the anthropogenic impact in the environment without any attendant reduction in the economic growth.

• 한국전산구조공학회논문집
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• 제23권5호
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• pp.483-491
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• 2010

본 논문에서는 점탄성 재료의 피로균열 성장을 분석하기 위해 ${\Delta}J$-적분을 이용하였다. J-적분의 계산 시 기존의 수치해석 방법이 아닌 해석적인 적분 해를 도출하여 계산시간을 절감하고 정확도를 크게 높였다. 계산 시 응력확대계수는 특정 균열에 대해 참조하는 방법이 아닌 유한요소해석을 통해 구하는 방법을 사용하였다. 기존의 ${\Delta}K$를 이용한 피로균열 예측과는 달리 크리프 변형계수, 단 두 개의 피로성장 모델 변수만을 가지고 다양한 하중과 하중주기에서의 피로균열 성장을 성공적으로 분석할 수 있었다.

• 자원ㆍ환경경제연구
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• 제31권4호
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• pp.887-908
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• 2022

본 연구는 경제성장과 환경개선 효과를 실증적으로 분석하기 위해 OECD 국가의 이산화황 배출량과 온실가스 배출량, 폐기물 배출량에 대해 환경쿠즈네츠 곡선이 존재하는가를 확인하였다. 패널분석결과, 환경오염물질에 따라 환경쿠즈네츠 곡선의 형태는 다르게 나타났다. 이산화황 배출량은 상대적으로 경제성장의 초기에 정점이 나타나 대부분의 국가가 정점을 지난 역U자형 곡선이 나타나는 반면 온실가스 배출량은 정점을 지나 감소하는 단계이다. 이때 제조업 비중은 온실가스 배출량을 증가시키며, 인구밀도와 연구개발은 배출량을 유의미하게 감소시키는 것으로 분석되었다. 한편, 폐기물에 대해서는 정점을 확인할 수 있는 환경쿠즈네츠 곡선이 존재하지 않았다. 분석대상인 환경오염물질은 각각 오염처리기술, 생산공정 전환, 소비구조 전환에 따라 환경개선 효과가 발생할 수 있는 사례를 대표한다고 보았다. 따라서 본 연구에서는 경제성장과 소득수준 향상이 있더라도 모든 환경오염물질에 대한 자발적인 배출량 감소는 기대하기 어려우며 정점이 지나기 위해서는 추가적인 지구 공동의 노력이 필요하다는 것을 확인하였다. 특히 폐기물은 소득수준보다 인구밀도와 산업구조의 영향이 더 크기 때문에 배출량을 줄이고 자원순환경제를 만들기 위해서는 추가적인 정책적 노력이 필요한 것으로 나타났다.

• 한국연초학회지
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• 제2권2호
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• pp.44-50
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• 1980

황색종 잎담배의 생장분석에서 얻어진 결과는 다음과 같다. 1. 개량말칭의 생장곡선은 대수변환하여 2차 회귀식에, 기타 작부는 Gomuertz방정식과 유사하였다. 2. 건물량에 있어서 최대생장기의 시점은 개량말칭의 경우에 이식후 50일경, 타 작부는40일경이고 최대생장기간은 모두 25일 였다. 3 건물량에 있어서 최대생장기의 생장속도는 개량, 일반, 나지작의 순서로 감소하였다. 4. 파기가 늦을수록 최대생장기 동안의 생장량은 증가했다. 5. 엽면적의 최대생장기간은 건물중에 비하여 약2일 단축되고 5일 정도 빠르게 나타났다.