• Wind and Structures
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• 제10권3호
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• pp.287-300
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• 2007

Wind action is a factor of fundamental importance in the structural design of light or slender constructions. Codes for structural design usually assume that the incident mean wind velocity is parallel to the ground, which constitutes a valid simplification for frequent winds caused by meteorological phenomena such as Extratropical Storms (EPS) or Tropical Storms. Wind effects due to other phenomena, such as thunderstorms, and its combination with EPS winds in so-called squall lines, are simply neglected. In this paper a model that describes the three-dimensional wind velocity field originated from a downburst in a thunderstorm (TS) is proposed. The model is based on a semi empirical representation of an axially-symmetrical flow line pattern that describes a stationary field, modulated by a function that accounts for the evolution of the wind velocity with time. The model allows the generation of a spatially and temporally variable velocity field, which also includes a fluctuating component of the velocity. All parameters employed in the model are related to meteorological variables, which are susceptible of statistical assessment. A background wind is also considered, in order to account for the translational velocity of the thunderstorm, normally due to local wind conditions. When the translation of the TS is caused by an EPS, a squall line is produced, causing the highest wind velocities associated with TS events. The resulting vertical velocity profiles were also studied and compared with existing models, such as the profiles proposed by Vicroy, et al. (1992) and Wood and Kwok (1998). The present model predicts horizontal velocity profiles that depend on the distance to the storm center, effect not considered by previous models, although the various proposals are globally compatible. The model can be applied in any region of interest, once the relevant meteorological variables are known, to simulate the excitation due to TS winds in the design of transmission lines, long-span crossings, cable-stayed bridges, towers or similar structures.

• 지구물리와물리탐사
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• 제5권4호
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• pp.291-298
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• 2002

본 연구에서는 지형을 포함한 2차원 MT 역산 알고리듬을 개발하였다. 역산 과정시 필요한 모델 반응 계산을 위하여 유한요소법을 이용하였다. 공기와 지표면의 경계를 기준으로 고도에 따라 각 요소들의 절점을 수직으로 이동시킴으로써 추가적인 계산시간의 증가없이 간편히 지형을 구현하였다. 역산에서는 공간적인 함수로서 라그랑지 곱수를 결정하는 알고리듬을 채택하여 역산의 분해능과 안정성을 높이고자 하였다. 수치모델 실험을 통하여 TM과 TE모드 자료의 지형효과를 고찰하였고, 수치 자료의 역산을 통하여 지형을 포함한 역산의 타당성을 살펴보았다. 또한 현장 자료에 대하여 적용하여 본 연구에서 개발된 지형을 포함한 MT자료 역산 알고리듬의 적용성을 확인하였다.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제15권1호
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• pp.23-32
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• 2009

Among welfare facilities for the elderly, necessity for the elderly welfare with diverse advantages is rising in the Small-scale Elderly Care Facilities. The government is expecting great demand in the future. However, current the Facilities lack construction plans that consider characteristics of the elderly. Accordingly, 14 case facilities located in JeollaNamdo and Gwangju were selected to comprehensively analyze the circulation of seniors at care facilities by computing spatial depth and visible area variables. As a result of this study, average spatial depth of bathroom, resting room, physical therapy room and dining hall that seniors frequently get in contact with was found to be deep, but visible area appropriate for the function of space was not available. It showed that the circulation for the elderly was deep spatially and long physically, and the spatial rank along circulation which is perceived visually by the admitted the elderly was clear, thus, providing them abundant visual experience supported by high openness as they move from private space to public space. The obtained visibility, however, was observed not to be matched with the function of each space. Since the Small-scale Elderly Care Facilities require various spaces within small surface area, actual functions of each space must be taken into consideration with hierarchical space organization to obtain an environment that stimulates senses such as vision and hearing. In addition, since the circulation of seniors using facilities must consider aging characteristics and delicate care on spatial depth and physical distances, in-depth studies on planning of the circulation in care facilities are deemed necessary.

• 한국환경복원기술학회지
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• 제23권4호
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• pp.13-30
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• 2020

This study aims to analyze the qualitative and quantitative effects of environmental policies in terms of green space management using logistic regression model(LRM). Landsat satellite imageries in 1985, 1992, 2000, 2008, and 2015 are classified using a hybrid-classification method. Based on these classified maps, logistic regression model having a deforestation tendency of the past is built. Binary green space change map is used for the dependent variable and four explanatory variables are used: distance from green space, distance from settlements, elevation, and slope. The green space map of 2008 and 2015 is predicted using the constructed model. The conservation effect of Ulsan's environmental policies is quantified through the numerical comparison of green area between the predicted and real data. Time-series analysis of green space showed that restoration and destruction of green space are highly related to human activities rather than natural land transition. The effect of green space management policy was spatially-explicit and brought a significant increase in green space. Furthermore, as a result of quantitative analysis, Ulsan's environmental policy had effects of conserving and restoring 111.75㎢ and 175.45㎢ respectively for the periods of eight and fifteen years. Among four variables, slope was the most determinant factor that accounts for the destruction of green space in the city. This study presents logistic regression model as a way of evaluating the effect of environmental policies that have been practiced in the city. It has its significance in that it allows us a comprehensive understanding of the effect by considering every direct and indirect effect from other domains, such as air and water, on green space. We conclude discussing practicability of implementing environmental policy in terms of green space management with the focus on a non-statutory plan.

• 보건행정학회지
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• 제29권3호
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• pp.312-322
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• 2019

Background: Since 2003, Korea has consistently shown the highest suicide rate among the Organization for Economic Cooperation and Development countries, and suicide remains the major cause of death. In particular, men are 2-3 times more likely to commit suicide than women, which called the 'gender paradox of suicide.' The areas with frequent suicide have spatially clustered patterns because suicide with a social contagion spreads around the neighborhood. The purpose of this study was twofold. The first was to estimate the hotspot areas of age-standardized male suicide mortality from 2008 to 2015. The second was to analyze the relationship between the hotspot areas and the regional characteristics for study years. Methods: The data was collected through the Korean Statistical Information Service. The study areas were 227 si gun gu administrative districts in Korea. The hotspot area was used as a dependent variable. Socio-demographic variables (number of marriages per 1,000 population, number of divorces per 1,000 population, and urbanization rate), financial variables (financial independence and social security budget), and health behaviors (EuroQol-5 dimension [EQ-5D], and depression experience rate) were used as independents variables. Results: The hotspot areas were commonly located in Gangwon-do, Chungcheongnam-do, Gyeongsangbuk-do, and Chungceongbuk-do. According to the results of panel logit regression, the number of divorces per 1,000 population, social security budget, and EQ-5D were statistically significant variables. Conclusion: The results of hotspot analysis showed the need for establishing a prevention zone of suicide using hotspot areas. Also, medical resources could be considered to be preferentially placed in the prevention zone of suicide. This study could be used as basic data for health policymakers to establish a suicide-related policy.

• Ocean and Polar Research
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• 제44권3호
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• pp.235-247
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• 2022

A marine protected area (MPA) is a spatially designated section of the ocean where the biodiversity is high. Munseom MPA has a unique underwater landscape including soft coral, subtropical fish, and benthos, attracting many scuba divers. This paper intends to evaluate the willingness-to-pay (WTP) for the scuba diving management policy in the Munseom MPA. As a stated preference valuation method, a choice experiment was applied to assess divers' preferences with economic values for the policy. The attributes used in the study included zoning (temporal closure), conservation education, daily permit, soft coral area, and diving fee. We collected 333 questionnaires through online and field surveys and used 296 after excluding incomplete responses for the final data analysis. Study results show that a six-month closure, a decrease in soft coral habitat, and the diving fee were statistically significant. A positive coefficient with regard to the six-month closure variable indicates that divers preferred the policy, and the marginal willingness to pay (MWTP) was estimated to be KRW 8,637 per person per dive. The aggregate WTP of KRW 233 million was obtained by multiplying the MWTP by the number of visiting divers per year. When comparing the levels of recreation specialization, more skilled divers preferred the management option. The results of this study will help predict the priority of management measures and the levels of acceptability among divers when diving management is implemented in Korea in the future. This study suggests that marine environmental policies need to consider divers as one of the important stakeholders for marine conservation.

• 대한지리학회지
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• 제49권3호
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• pp.405-422
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• 2014

부동산 가격을 추정하기 위한 헤도닉 모형(hedonic model)의 적용에서 가장 중요한 사안은 모형의 정확한 구성과 하부시장의 구획이라 할 수 있다. 모형의 구성에 대해서는 비교적 활발한 개선 노력이 있었으나 하부시장 구획은 상대적으로 큰 관심을 받지 못하였다. 그러나 부동산 가격형성 과정의 공간적 범위 파악이 선행되지 않으면 헤도닉 모형의 적용 결과는 그 정확성이 저하될 수밖에 없다. 본 연구는 헤도닉 모형의 성능 개선에 초점을 두고, 서울시 25개 자치구 중 상대적으로 이질적인 부동산 집단으로 구성된 강남구와 비교적 균일한 부동산 집단으로 이루어진 중랑구를 사례지역으로 하여 하부시장 구획을 시도하였다. 먼저 하부시장 구획을 위한 투입변수로 혼합 GWR(Mixed GWR) 모형에서 산출된 가변 회귀계수(variable coefficients)를 사용하였다. 헤도닉 모형의 회귀계수는 부동산을 구성하는 속성항목(attributes)의 잠재가격(shadow price)으로 해석할 수 있기 때문이다. 다음으로 공간적으로 연접된 하부시장을 구획하기 위해 최소신장트리(minimum spanning tree)에 기반한 SKATER 앨고리듬을 사례지역에 적용하였다. 마지막으로 다수준 모형(multi-level model)을 적용하여 구획된 하부시장 결과의 적정성을 검토하였다. 검토 결과, 중랑구는 하부시장이 존재하지 않음을, 강남구는 간선도로를 중심으로 한 5개의 하부시장으로 구분하는 것이 합리적임을 확인하였다. 간선도로와 같은 도시의 인프라는 하부시장 구획에 있어 지금까지 큰 주목을 받지 못한 변수였으나 본 연구를 통해 그 중요성이 실증적으로 확인되었다.

• Ocean and Polar Research
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• 제40권1호
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• pp.1-13
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• 2018

Previous studies have indicated a great regional difference in Sea Level Rise (SLR) in the Pacific and it has been suggested that this is linked to climate variability over the past two decades. In this study, we seek to identify the possible linkage between regional sea level and Pacific climate variability from altimetry-based sea level data (1993-2012) and further investigate how the Pacific sea level has changed spatially and temporally over the past 60 years from long-term sea level reconstruction data (1953-2008). Based on the same method as Zhang and Church (2012), the Inter-annual Climate Index (ICI) associated with the El $Ni{\tilde{n}}o-Southern$ Oscillation (ENSO) and the Decadal Climate Index (DCI) associated with Pacific Decadal Oscillation (PDO) are defined and then the multiple variable linear regression is used to analyze quantitatively the impact of inter-annual and decadal climate variability on the regional sea levels in the Pacific. During the altimeter period, the ICI that represents ENSO influence on inter-annual time scales strongly impacts in a striking east-west "see-saw mode" on sea levels across the tropical Pacific. On the other hand, the decadal sea level pattern that is linked to the DCI has a broad meridional structure that is roughly symmetric in the equator with its North Pacific expression being similar to the PDO, which largely contributes to a positive SLR trend in the western Pacific and a negative trend in the eastern Pacific over the two most recent decades. Using long-term sea level reconstruction data, we found that the Pacific sea levels have fluctuated in the past over inter-annual and decadal time scales and that strong regional differences are presented. Of particular interest is that the SLR reveals a decadal shift and presents an opposite trend before and after the mid-1980s; i.e., a declining (rising) trend in the western (eastern) Pacific before the mid-1980s, followed by a rising (declining) trend from the mid-1980s onward in the western (eastern) Pacific. This result indicates that the recent SLR patterns revealed from the altimeters have been persistent at least since the mid-1980s.

• Journal of Radiation Protection and Research
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• 제17권1호
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• pp.43-56
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• 1992

입자 수송방정식에서 각변수(angular variable)를 각분할근사법으로 해석할 때 나타나는 이상 현상인 ray effect를 치유할 수 있는 방법의 하나로써, 유한 분할각(discrete angle quadrature)을 입자속의 공간적 분포로써 조종하는 방법인 각분할요소법 (discrete elements method)을 근거로 하여 2차원 직각좌표계에서의 입자 수송 해석 프로그램(TWODET)을 개발하였다. 평판형 등방적 고정선원이 존재하는 균질 사각형 흡수체에 대해 TWODET로 해석한 결과, 각 요소가 K-2, L인 경우에도 DOT 4.3(S-10)에서보다 ray effect 치유에 더 효과가 있음을 확인하였다. 그러나, 계산시간은 기존의 각분할법에서보다 약 4배 더 소비되었다. 선원에서 바로 진공(vacuum boundary)으로 떨어지는 구조의 경우, TWODET의 결과에서도 심한 왜곡을 보이고 있는데 선원과 바로 이웃한 진공간의 급격한 불연속성으로 인함으로 추측된다 고정선원이 있는 매질에 강한 흡수체가 추가된 구조의 경우에서도 TWODET(K-3, L-4)로 DOT 4.3(S-10)보다 좋은 결과를 보였다.

• 대한핵의학회지
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• 제38권3호
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• pp.241-252
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• 2004

목적: 다수의 뇌 자료를 기반으로 구성된 통계적 화률뇌지도는 복잡하고 개인적인 편차가 큰 뇌의 형태학적, 기능적 특성을 분석하는데 유용하다. 특히 최근에 한국인의 정상 MR 영상을 기반으로 한 구조적 기능적 뇌 표준판과 구조적 확률뇌지도가 완성되었으며. 부검뇌의 조직절편을 활용한 세포구축학적 확률뇌지도가 도입되었다. 이 연구에서는 이들 자료를 활용하여 뇌 영상의 국소계수를 객관적으로 측정하기 위한 정량화 기법을 개발하였으며, 이를 이용하여 정상 한국인의 뇌 영상자료를 분석하였다. 대상 및 방법 : T1 MRI와 FDG PET에 대한 뇌 표준판을 성별, 연령별로 개발하였으며, 한국인 정상 MR 영상으로 만들어진 89개 뇌 영역의 구조적 확률뇌지도와 독일 율리히 연구센터에서 도입한 13개 브로드만 영역에 대한 세포구축학적 확률뇌지도를 뇌 표준판 위로 각각 비선형 변환하였다. 확률뇌지도에 정의된 각 뇌 영상의 국소계수는 확률에 의한 가중평균 또는 가중합으로 구하였다. 확률뇌지도를 이용한 예비 연구로 정상 노화에 따른 포도당대사의 변화가 대상회 내에서 전 후 위치에 따라 다르게 나타나는 가를 조사하였다. 결과: SPM과의 연계된 사용을 고려하여 Matlab 상에서 작성된 정량화 프로그램은 20초 미만에 1개의 공간정규화된 영상을 처리할 수 있었다. 대상회 포도당 대사에 대한 분석에서 후대상회에 대한 문측-전대상회 및 미측-전대상회의 계수 비는 정상 노화에 따라 매우 유의하게 감소하였다. 즉. 문측-전대상회/후대상회는 매 10년마다 3.1%씩 감소하였으며($P<10^{-11}$, r=0.81) 미측-전대상회/후대상회는 1.7%씩 감소하였다($P<10^{-8}$, r=0.72). 문측-전대상회와 미측-전대상회의 계수비 감소 역시 유의하였다(P<0.0005. r=0.52, 1.5%/year). 결론: 서양인 뇌에 기반한 확률뇌지도는 그동안 제한적으로만 사용되어 왔으나 한국인 뇌 표준판과 확률뇌지도 및 이 연구에서 개발한 정량화 기법은 일반에 공개하기로 하여 더욱 널리 쓰이게 되면 국내 뇌 연구 활성화에 기여할 것으로 기대 된다.