• Journal of radiological science and technology
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• v.14 no.2
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• pp.45-53
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• 1991

SPECT 영상에서 콤프톤 산란 광자는 공간분해능의 감소와 그 양을 측정하는데 있어 정확성과 정밀성을 감소시킨다. 이와같은 콤프톤 산란의 영향을 감소시키기 위하여 사용하는 대부분의 보정방법은 선원의 위치로부터 거리의 단일지수함수로 대칭인 산란분포함수를 고려하게 된다. 본 연구는 균등 및 불균등 산란에 대한 산란분포함수를 얻기 위하여 보다 현실적인 접근방법을 시도하였다. 산란 및 비산란광자의 공간분포와 에너지분포를 얻기 위하여 뼈, 폐, 물의 균등 및 불균등 분포로 된 원통형의 팬톰 속에 $^{99m}Tc$의 선선원 및 점선원을 놓고 Monte Carlo Simulation을 하였으며, 깊이의 함수, media의 접촉영역으로부터 선원거리 및 산란체의 밀도의 변화로 표현한 산란분포함수(SDF)를 얻었다. 산란분포함수는 균등한 뼈, 폐, 물에서는 선원위치로부터 거리의 단일지수함수(single exponential functions)로 대칭으로 나타났으며, 두 물체의 조합에서는 2중지수함수(dual exponential functions)로 비대칭으로 나타났다. 산란분율은 20% window photopeak에서 총 계수의 8%에서 53%까지 다양한 변화가 있었으며, 지수함수의 기울기는 $0.1{\sim}0.9\;cm^{-1}$의 범위로 나타났다. 불균등 산란체에서 얻은 산란분포함수는 SPECT 영상에 있어 콤프톤 산란의 감소에 대한 보다 정확한 보정방법의 개발에 필요한 정보를 제공할 것이다.

• 한국ITS학회:학술대회논문집
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• 2003.11a
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• pp.221-225
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• 2003

• Journal of Korean Society of Forest Science
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• v.95 no.4
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• pp.476-483
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• 2006

This study tried to estimate the concentration indices of 15 forested national parks using Gini coefficient and Lorenz curve which can be measure the degree of inequality. The concentration indices were estimated by two parts which are yearly index for the periods of 1997-2005 and travel origin area(city or province) distribution index each national park. The empirical results were as follows: first, yearly Gini coefficients showed severe inequality. Particularly, 2004 and 2005 Gini coefficients were .453 and .446. which are intensive inequality compared with other years. Second, in travel origin area distribution each national park, Gini coefficients of Bukhansan and Kyeryungsan national park were .916 and .855 which are the great inequality compared with other national parks. The other hand, Gini coefficients of Dukyusan and Byunsanbando national parks were .508 and .628 which are the lowest inequality. The national park policy manager should find out the factors of concentration and deconcentration each year and national park and decided the visitor distribution policy which visitor size and scope for balancing the natural resources use.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.114-115
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• 2019

이 논문은 무선 전력 전송을 이용하는 마우스의 급전 패드와 리시버 설계 방법을 제안한다. 마우스의 급전 패드는 코일의 턴간 간격을 불균등하게 조절하여 균일한 자기장을 급전 패드 상에서 얻게 하며, 집전코일은 급전코일과 비교해 크기가 작기 때문에 낮은 결합계수와 품질계수를 가져 원하는 전압을 얻기 어려운데 이를 위해 PCB 코일을 멀티레이어로 제작하고 PCB 패턴의 폭을 조절하여 높은 인덕턴스를 갖게 설계한 후 유한요소해석을 통해 설계한 시스템을 시험했다.

• Journal of Korea Water Resources Association
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• v.54 no.12
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• pp.1223-1232
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• 2021

In this study, a new analysis method by using a "Discharge Gini Coefficient" is presented to determine the degree of inequality in daily discharge throughout the year. The Discharge Gini Coefficient can be calculated using the area relationship with the cumulative percentage of the daily mode discharge in the ascending order according to the cumulative percentage of the date of occurrence of the daily discharge throughout the year. The Discharge Gini Coefficient is presented as a value between 0 and 1, and the degree of inequality can be divided into 5 levels. The Discharge Gini Coefficient can be used to estimate the discharge stability of the downstream point relative to the upstream point. In addition, it is possible to quantify the influence of each reference discharge on the total inequality. The applicability of the Discharge Gini Coefficient was reviewed using long-term daily discharge data at eight points upstream and downstream of the four major rivers in Korea. The Discharge Gini Coefficient can also be used to analyze the discharge control effect in the downstream by the upstream dam.

• Journal of Korean Society of Transportation
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• v.20 no.6
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• pp.45-56
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• 2002

In this research we estimated regional gross fixed capital stock of transport sector, such as road railroad, airport and seaport during 1968-1997 in Korea. We also compared our estimation results with those of Korea and Japan. As basic analytic method, we used the regional allocation method. To estimate regional gross fixed capital stock of transport sector, we used the basic data on national wealth surveys in 1997, regional land price index and regional facilities index in transport sectors. We used the most reasonable data in the process of estimation after reviewing the collected data In order to get the reasonable capital stock by regions. we chose the allocation index which can minimize the difference between the estimated result and the real regional capital stock in the process to allocate the total gross capital into the regions. Compared our results with those of other researches in Korea, estimates in our research project could be said more accurate than those.

• Journal of the Economic Geographical Society of Korea
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• v.26 no.4
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• pp.359-374
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• 2023

The main purpose of this paper is to explore the relationship between the transformation of Chinese regional development policy and trends in spatial inequality in mainland China. More specifically, it has attempted to identify the effects of Chinese regional development policies on regional economic inequality by investigating the coefficient of variation and Gini coefficient with GRDP in the province level. Regional inequality in China had increased from 1979 economic reform, but has eased since the 10th Five Year Plan(2001~2005) due to large-scale state investments in the western, central and northeastern regions. However, the analysis is likely to be resulted from the national level. Trends in regional inequality are differentiated in accordance with the eastern, central, northeastern and western regions. For example, regional inequality in the central region has increased, whereas other three regions has decreased since the 10th Five Year Plan. It has played a role in cutting down regional inequality in the national level. In particular, the central region has kept inequality since the 12th Five Year Guideline. It has led to the convergence of the regional economies in the national level. It has stemmed from some limits to greater regional policies in the Central region enforced in the 11th Five Year Guideline(2005~2010).

• Journal of Korean Society of Steel Construction
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• v.17 no.3 s.76
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• pp.317-324
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• 2005

The specially orthotropic plate theory is used to analyse three-span continuous composite slab bridges with elastic intermediate supports. A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures, with irregular cross sections and with arbitrary boundary conditions, was developed and the result of application of this method to the three-span continuous composite slab bridges with elastic intermediate supports is presented. This type of bridge represents either concrete or sandwich type three-span bridge on polymeric supports for passive control or on actuators for active control. Any method may be used to obtain the deflection influence surfaces needed for this vibration analysis. The finite difference method is used for this purpose in this paper. The influence of flexural stiffnesses and the modulus of the foundation are studied.

• The Korean Journal of Applied Statistics
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• v.23 no.4
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• pp.767-776
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• 2010

Frontier (1976) suggested a criterion based on the expected length of ordered random intervals under the Broken-stick model (Barton and David, 1956) to determine the optimal number of principal components retained. It is considered to be one of the methods that provide the most consistent simulation results (Jackson, 1993). This study is aimed to propose a method using the distribution of ordered random intervals to evaluate the contribution of principal components. We also examine several types of Gini indices along with the corresponding Lorenz curves to visualize the overall equivalence of those contributions.

• Composites Research
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• v.17 no.3
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• pp.23-28
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• 2004

A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures, with irregular cross sections and with arbitrary boundary conditions was developed and reported by Kim, D. H. in 1974. In this paper, the result of application of this method to the three span continuous reinforced concrete bridge with elastic intermediate supports is presented. Such bridge represents either concrete or sandwich type three span bridge on polymeric supports for passive control or on actuators for active control. The concrete slab is considered as a special orthotropic plate. Any method may be used to obtain the deflection influence surfaces needed for this vibration analysis. Finite difference method is used for this purpose, in this paper, The influence of the modulus of the foundation and $D_{22}$, $D_{12}$, $D_{66}$ stiffnesses on the natural frequency is thoroughly studied.