• Journal of Korea Multimedia Society
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• v.6 no.7
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• pp.1159-1168
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• 2003

In this paper, a new wavelet filter design algorithm is proposed which optimizes energy compaction of transformed coefficients. The filter, designed by the proposed algorithm enhances the coding gain of the system with fixed quantizer by most unevenly distributed energy in transform domain. The coding gain function was extended to obtain the optimal filter coefficients in each stage. The experiments showed that the filter designed by proposed method outperforms conventional filters in energy compaction rate.

• Journal of Korean Society of Rural Planning
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• v.22 no.2
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• pp.109-119
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• 2016

Most of countries are trying to increase the supply of renewable energy as the substitute of the fossil energy for reducing greenhouse gas emissions. However, renewable energy sources account for only about 3.86% of the total Korea primary energy supply. To increase the rate of renewable energy in Korea's energy consumption, various policies for expanding the use of renewable energy should be applied. Also these policies should be consider renewable energy resources distribution and regional inequality. In this study, the potentials of photovoltaic, wind power and bioenergy from rice straw, livestock waste and food waste are calculated and the distribution characteristic and regional inequalities are analyzed using Gini's coefficient and Gini decomposition method. As the results, technical potentials of photovoltaic and wind power of city region(Gu) has more potential rate than theoretical potentials. Livestock waste has the most unequal distribution (Gini's coefficient: 0.617) among renewable resources.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.193-193
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• 2015

오염원과 취수원이 인접한 위치에 존재하는 국내 하천 같은 경우 취수 시설의 안전한 관리를 위하여 오염물의 2차원 혼합 거동에 대한 연구가 필요하다. 하천에서의 오염물 혼합 거동을 분석하기 위하여 일반적으로 농도와 분산 정보 수집을 위한 추적자 실험을 수행해왔다. 기존에 수행된 추적자 실험들은 형광염료, 방사선 물질, 고형 물질 등과 같은 추적자를 인위적으로 주입하여 사용하였다. 그러나 수온, 전기전도도(electrical conductivity), 이온화 물질 등과 같은 자연 추적자(natural tracers)를 이용하는 추적자 실험은 인공추적자 물질을 대체할 수 있는 방안으로서, 기존 추적자 실험과 비교하여 경제적, 환경적인 효과와 하폭이 넓은 중규모 이상의 하천에서도 수행할 수 있다는 장점을 가지고 있다. 본 연구에서는 진천천과 금호강이 합류하는 낙동강 중류 구간에서 횡혼합 연구를 위하여 전기 전도도 추적 실험을 수행하였다. 강정고령보 직하류에서 낙동강 좌안쪽에서 합류하는 금호강과 진천천의 경우 인근 공업단지와 하폐수처리장으로부터 많은 비점오염원과 점오염원이 유입된다. 두곳의 지류에서 모두 높게 측정되었던 전기전도도를 자연 추적자로 선택하였다. 지류의 경우 전기전도도를 측정할 수 있는 센서를 측정 지점에 설치하여 측정하였으며, 본류인 낙동강의 경우 정해진 측선을 따라 센서가 고정된 보트를 이동하며 데이터를 취득하였다. 지류인 금호강과 진천천의 경우, 합류 전 전기전도도의 농도의 횡분포는 균일한 분포를 나타냈으며 농도의 평균값은 합류 전 낙동강 본류의 기저농도 보다 더 높은 값을 나타내었다. 지류 합류 이후의 낙동강 본류에서는 지류로부터 유입된 오염물질로 인하여 횡방향으로 불균등한 전기전도도 농도 분포를 나타내었으며 오염물질이 점점 하류 쪽으로 이동하면서, 횡방향 농도경사의 크기가 줄어들었다. 유관모멘트법을 농도곡선에 적용하여 횡방향 분산계수를 산정하였다. 산정된 횡분산계수의 값은 Rutherford (1994)가 제안한 분산계수의 범위에 포함되는 것으로 나타났다.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.74-74
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• 2017

자연하천에서 수자원의 원활하고 안전한 관리에 있어서 오염물의 혼합 거동에 대한 이해는 매우 중요하다. 대부분의 자연하천의 경우 만곡부 및 합류부와 같은 복잡한 지형을 갖고 있으며 이러한 경우 하천의 흐름이 복잡한 형태를 갖게 된다. 특히 수생태계에 많은 영향을 미치는 하폐수 처리장 처리수는 대부분 1차적으로 지류로 방류되어 이후 본류로 지속적으로 유입되게 된다. 이러한 오염물질이 지류로부터 본류로 혼합되는 합류부 구간의 경우 일반적인 1차원 혼합이 아닌 횡방향을 포함하는 2차원적인 혼합 거동에 대한 분석이 필요하다. 본 연구에서는 금호강과 진천천이 좌안으로부터 오염물질이 지속적으로 유입되는 낙동강 중류구간 합류부에서의 혼합 구간의 연구를 위하여 횡분산계수 산정을 위하여 전기전도도(electrical conductivity: EC)를 이용한 농도 추적 실험을 수행하였다. 낙동강 본류에서 정해진 측선을 따라 센서가 설치된 보트를 이용하여 실시간으로 농도, 수리량 데이터를 GPS 위치 데이터와 함께 취득하였다. 또한 실험으로부터 취득한 자료를 바탕으로 2차원 이송-확산 혼합 거동 모델인 CTM-2D 수치모형을 이용하여 모의하였다. 실험 수행 결과, 지류인 금호강과 진천천의 EC 농도가 합류 전 낙동강 본류의 EC 기저농도 보다 더 높은 값을 나타내었다. 지류의 유입으로 인하여 본류 좌안 쪽에서 전기전도도의 값의 상승을 확인할 수 있었으며 하류로 이동할수록 불균등했던 전기전도도의 분포가 횡방향 혼합을 통하여 점점 균등한 분포로 전환되는 것으로 나타났다. 또한 2차원 혼합 거동 분석에 필요한 횡 분산계수 산정을 위해 모멘트법, 해석해를 이용한 추적법, 수치모형을 통한 역산법을 통해 산정하여 결과를 비교하였다. 그 결과 모멘트법의 경우 다른 방법들에 비하여 전반적으로 과소 산정하는 경향을 나타내었다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.1 s.4
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• pp.45-52
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• 2004

There are many cities installing ITS(Intelligent Transportation Systems) and running TMC(Trafnc Management Center) to improve mobility and safety of roadway transportation by providing roadway information to drivers. There are many devices in ITS which collect real-time traffic data. We can obtain many valuable traffic data from the devices. But it's impossible to avoid missing traffic data for many reasons such as roadway condition, adversary weather, communication shutdown and problems of the devices itself. We couldn't do any secondary process such as travel time forecasting and other transportation related research due to the missing data. If we use the traffic data to produce AADT and DHV, essential data in roadway planning and design, We might get skewed data that could make big loss. Therefore, He study have explored some imputation techniques such as heuristic methods, regression model, EM algorithm and time-series analysis for the missing traffic volume data using some evaluating indices such as MAPE, RMSE, and Inequality coefficient. We could get the best result from time-series model generating 5.0$\%$, 0.03 and 110 as MAPE, Inequality coefficient and RMSE, respectively. Other techniques produce a little different results, but the results were very encouraging.

• Journal of the Korean Geotechnical Society
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• v.23 no.11
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• pp.5-14
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• 2007

In this study, Matsuda formula used to evaluate the loads acting on the pillar was investigated and load reduction factor(${\alpha}$) was evaluated by numerical analysis to better apply for the design. From the results, normal stress was concentrated to one side due to excavation of preceding tunnel after construction of pillar. And 86.5% of maximum normal stress was revealed partly unequally when the ground was poor. By numerical analysis, $14{\sim}83%$ of total loads calculated by Matsuda formula decreased and then, from these results, load reduction factor(${\alpha}$) was estimated. From now on, stability and economic aspects could be guaranteed by applying the load reduction factor(${\alpha}$).

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.31 no.4
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• pp.29-47
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• 2020

This study uses Gini coefficient to index the inequality of academic information resource among universities to identify the areas where the gap is extremely severe, and analyzes the Gini coefficient over time for 10 years to show how the gap is changing. In addition, the degree and characteristics of the gap appearing by type of universities such as metropolitan universities, local national universities, private universities, and colleges were also compared. As a result, first, the university library academic information infrastructure showed a severe level of disparity (0.6 - 0.9), and the inequality was more severe in serials, electronic resources, and reference service. Even when the relative Gini coefficient was calculated considering the number of students, the inequality was over 0.4 in serial etc. Second, the Gini coefficient trend over the last decade shows that the inequality has decreased toward equality in the re-education time of employees and electronic information resources, but not in other sectors. Third, it was found that special universities and universities in the metropolitan area showed a large gap between universities of the same kind, and local national universities showed the best gap level as well as the best academic information infrastructure.

• Journal of the Economic Geographical Society of Korea
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• v.25 no.4
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• pp.484-498
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• 2022

The purpose of this study is to analyze the location, distribution and its change of photovoltaic power generation in the scale of municipality(Si-Gun-Gu). First the distribution of photovoltaic power generation was analyzed in 2020, and second, from 2017 to 2021, we tracked the increase in capacity of power generation facilities in each Si-Gun-Gu. As a result, the distribution and increase of photovoltaic power generation were concentrated in some regions and the unequal distribution of photovoltaic power generation has been identified through Gini coefficient.

• Journal of the Economic Geographical Society of Korea
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• v.14 no.3
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• pp.377-393
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• 2011

This study aims to indicate the spatial characteristics of the changes in the Korean farm land. In particular, we analyze the spatial diffusion patterns of organic farms increasing rapidly with the growth in the agricultural product markets as well as the demand for safe food and sustainable growth. For the purpose, we examine the changes in the distribution patterns of organic farms between year 2000 and 2005. We analyze the agglomeration pattern by Location Quotient (LQ) and Local indicator of spatial association (LISA). Organic farms have been spread out from the outscuirts of Seoul, the capital city, to the traditional agriculture spetilized area in the southern parts of the nation. In order to analyze the relationships between organic farm distribution and the geographical variables affecting the organic farming, we develop multivariate regression models. Our findings indicate that organic farming is related with the number of agriculture-based business and information technique adaptation as well as the level of education and farmers age.

• Journal of the Economic Geographical Society of Korea
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• v.22 no.4
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• pp.513-525
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• 2019

In Seoul, the subway system has been in use since 1974 and is the most frequently used travel mode accounting for approximately 40% of passenger journeys in 2015. As such the subway system is widely adopted by people and therefore, can have great impacts on their everyday life. However, it is easily noted that transit resources are not distributed spatially uniform, in other words, not all parts of the city gain the same benefits from their networks. This study aims to examine the inequity of spatial distribution of subway networks based on accessibility. Accessibility of subway networks are calculated based on the time-distance between stations and then equity is measured using the Gini index. Resulted map of subway accessibility shows that the benefits are not evenly distributed in Seoul with a pattern of highly accessible core - less accessible periphery areas. Also the subway accessibility network has fairer distribution against the employees' distribution rather than the distribution of general population or possibly transit dependent groups.