• Korean Journal of Soil Science and Fertilizer
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• v.29 no.2
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• pp.150-157
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• 1996

This study was conducted to observe the heavy matal contents of paddy soil and brown rice under long term fertilization with different soil amelioration materials. The contents of 0.1N HCl extractable Cu and Zn of surface soil increased in the plots of long term application with urea, ammonium sulfate, compost, lime and silicate fertilizers. The Cu and Zn contents of brown rice showed decreasing trends in same treatments of fertilizers and soil amelioration materials. But the contents of Cd and Pb in soil and brown rice were not affected in long term fertilization with soil amelioration materials.

• Journal of the Korea Concrete Institute
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• v.17 no.2 s.86
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• pp.281-290
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• 2005

This paper presents experimental and analytical studies on long-term behavior of square CFT columns under central axial loading. Two loading cases are considered; (1) the load applied only at the inner concrete of the column and (2) the load applied simultaneously on both the concrete and the steel tube. Four specimens of square CFT columns were tested under the two loading cases, and basic creep test for two concrete specimens was performed to find out the creep properties of the inner concrete. Three-dimensional finite element analysis models were established and verified with the experimental results. The verification shows that the prediction for the long-term behavior of actual square CFT columns is possible from the three dimensional finite element modeling considering the bond behavior between steel tube and inner concrete. Also, experimental results and numerical calculations revealed that the bond stress Induced by the confinement pressure as well as the slip between inner concrete and steel tube were increased with time In the first loading case. However, the confinement by the loading Plate was decreased with time while increasing confinement effect by the steel tube was observed over time. In contrast no confinement effects occur in the second loading case.

• Communications for Statistical Applications and Methods
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• v.18 no.1
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• pp.137-146
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• 2011

Long-term care insurance is a social insurance system that provides benefits to the elderly who have difficulty taking care of themselves for a period of at least 6 months. This system was started in July, 2008 and it is very important to set proper judgement ratings for the approval process. We try to develop and improve the judgement rating system using decision tree models. Our tree model is found to be more stable and efficient than the previous one.

• Journal of the Korean GEO-environmental Society
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• v.14 no.9
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• pp.13-19
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• 2013

The Chongok karst cave which is located in Donghae-city, has high tourist and educational value due to existence of many doline(sink hole). Whereas this cave is easy to approach for the tourists, because this cave is located near the downtown, a high environmental riskiness such as sewage flowing has been also involved. In study, we observed the variation of water quality with long-term monitoring and investigated the possibility of existence of impact factor to water eco-system and determined the proper long-term monitoring factor among many monitoring criteria. The groundwater quality was maintained in the range of about $14^{\circ}C$ in temperature, over 10mg/l in dissolved oxygen and 7-8 in pH, so the impact factor in water eco-system was not observed. The guide line to make sure of tourist safety was determined to 60mm/d as daily rainfall. The conductivity was suggested to main factor for long-term monitoring main factor and pH/turbidity was suitable for the supplementary factor. For the seasonal variation monitoring, ORP was recommended.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.40-40
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• 2017

최근 2014년 마른장마의 영향으로 중부 지방에 가뭄이 발생하였으며, 장마철 강수부족은 2015년까지 영향을 미친바 있다. 이로 인해 소양강 댐은 역대 최저수위를 기록하였으며, 일부 지역에서는 제한급수, 농업용수 부족 등의 피해가 발생하였다. 일반적으로 가뭄은 발생순서에 따라 기상학적, 농업적, 수문학적 가뭄 등으로 분류하고 있다 (Wilhite and Grantz, 1985). 기상학적 가뭄은 농업 및 수문학적 가뭄에 영향을 미치는 가뭄의 시작 단계를 의미하며, 가뭄을 판단하는데 있어 중요한 요소라 할 수 있다. 기상학적 가뭄을 정량적으로 판단하기 위해 SPI, PDSI, PN 등이 활용되고 있으며, 특히 강수량 기반의 SPI는 계산과정이 쉽고, 다양한 지속시간(3, 6, 9, 12개월 등)에 따라 가뭄을 객관적으로 판단할 수 있어 가장 활발하게 이용되고 있다(Mckee et al., 1993). 최근 기상청은 대기와 해양-해빙 모델을 접합한 GloSea5의 장기예보자료를 활용하여 월 내지 계절 가뭄전망을 위한 기상학적 가뭄지수를 현업에 활용하고 있다. 다만 국내에서는 주로 단기가뭄(1~3개월)이 빈번하게 발생함에 따라 짧은 예보선행시간을 갖는 가뭄전망에 대한 평가에 집중되어 왔다. 2014, 15년에는 이례적으로 2년 연속 가뭄이 지속된바 있으며, 장기가뭄(3개월 이상)에 대한 전망정보의 필요성이 증가하고 있다. 본 연구에서는 장기예보자료 기반의 기상학적 가뭄전망정보를 산정하고, 2015년 가뭄을 대상으로 활용성을 평가하였다. 이를 위해 ASOS 59개 지점의 관측강수량, GloSea5의 미래예측(Foreacst) 및 과거재현(Hindcast) 자료를 활용하였으며, 다양한 지속시간(3, 6, 9, 12개월)에 대한 SPI를 산정하였다. 또한 예보선행시간(1~6개월)에 따른 SPI와 관측자료 기반의 SPI 간의 통계적 분석(상관계수, 평균제곱근오차)을 수행하여 전망정보의 정확도를 평가하였다.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.4
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• pp.125-134
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• 2013

Since 2012, the local autonomous governments, under the recommendations regarding cancellation of local committees directing overly-unexecuted urban planning facilities, have tried to prove validity of such facilities. Factors such as specific standards of cancelation process, will execute policies, diversification of local conditions, connectivity to nearby facilities and possible arise of civil complaints, however, all hinder overly-unexecuted urban planning facilities from getting revitalized. Considering that these unexecuted facilities that local governments have to manage increase in number every year, the burden continuously increases for the governments due to the difficulty of setting aside budget for performing validity checks on such facilities. This research aims to analyze the criteria regarding efficient and systematic method on confirming validity of overly-unexecuted urban planning facilities, to establish into several different processes according to defined categories, and to objectify and quantify such standards. Also, using intelligent spatial information such as digital map, LiDAR data and ortho-images, spatial information analysis method suitable for reassessment was chosen and applied to execute validity analysis regarding overly-unexecuted urban planning facilities.

• Proceedings of the Korean Society of Computer Information Conference
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• 2010.07a
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• pp.353-356
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• 2010

고객관계관리(CRM)세계시장개방은 일련의 과정 및 특정고객과 장기적인 관계를 정립하여 이윤을 추구하는 영업전략 지원시스템으로 구성되어 있다. 이 연구를 통해 e-쇼핑몰에서의 e-CRM의 구성요소들이 소비자의 고객만족과 충성도에 어떠한 영향관계를 미치는가를 조사한다. 또한 e-CRM구성요소들을 통한 고객의 만족이 인터넷을 통한 구전효과나 구매선택에 어떠한 영향을 미치며, 각각의 요소들의 가중치를 알아보았다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.28 no.3
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• pp.65-74
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• 2005

본 연구는 기계고장 시 대체경로를 고려한 새로운 유사계수와 주어진 기간 내 수요변화를 고려하여 제조 셀을 구성하는 방법론을 개발하는 것이다. 본 연구의 방법론은 2단계로 나누어진다. 1단계에서는 기계고장 시 이용 가능한 대체경로를 고려하여 새로운 유사계수를 제시하고 유전자 알고리즘을 활용하여 부품 군을 식별하는 것이다. 셀 응용의 성패를 좌우하는 주요한 요소들 중 하나는 수요변화에 대한 유연성으로 수요변화, 이용 가능한 기계의 능력 및 납기일에 따라 셀을 재구성하기가 쉬운 일은 아닐 것이다. 대부분의 논문에서 제안한 방법들은 단일기간에 대한 고정 수요를 고려하였으나, 수요의 변화로 인하여 셀 설계는 대부분의 연구에서 고려한 단일기간보다는 장기적인 면을 고려해야 할 것이다. 수요가 변화하는 상황에서 운용요소와 일정요소를 고려한 셀 구성에 대한 새로운 방법론을 2단계에 소개한다.

• Journal of Korea Technology Innovation Society
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• v.7 no.2
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• pp.441-458
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• 2004

이동망의 착신접속서비스는 각국에서 bottleneck 서비스로 인식하고 규제당국에서 원가에 근거하여 규제하고 있다. 원가에 의한 규제 방식으로 과거에는 회계자료를 근거로 한 역사적 원가가 사용되어 왔으나 최근에는 유선망의 경우처럼 bottom-up 방식의 장기증분원가(Long Run Incremental Cost ： LRIC)를 적용하는 사례가 증가하고 있다. LUC를 산정하기 위해서는 공학적인 기준에 따라 이동망을 설계하여 정확한 망 구성요소별 소요량을 측정하고 이를 투자비로 전환하는 작업이 필요하다. 유선망의 경우는 LRIC산정을 위한 망 설계방법론이 비교적 잘 확립되어 있으나, 이동망의 경우는 망 설계 및 망 구성요소별 소요량 산정방법론에 대한 연구가 부족한 실정이다. 본 고에서는bottom-up방식의 이동망 LRIC산정관련 해외 사례를 살펴보고 국내 실정에 적합한 이동망 설계 방법과 망 구성 요소별 소요량 산정 방법론을 제시해보고자 한다.

• Information Systems Review
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• v.10 no.3
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• pp.21-38
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• 2008

After the introduction stage, Korean mobile game market is approaching to the growing stage leading mobile contents market. The environment for the mobile contents business is getting better by the expansion of the 3G mobile networks and the enhancement of the mobile devices. In this research, at a content level, not a service level, market success factors of mobile games and the differences by genres and their changes over time were investigated through the analysis of the real market data of mobile games launched by a Korean mobile carrier. The most important factors for market success, especially for the genres of RPG/Tycoon/Simulation and Shooting/Action/Arcade, were found to be the 'design' factor and its effect turned to be getting stronger as time goes by after the launch. Consumers' purchase rate was actually higher for the mobile games of popular genres or in relation with socially popular subject matters. Also 'design' and 'creativity' factors which are related to the quality of contents, have gotten more important over time. One of the most interesting results was that there existed a "blue ocean" genres like Sports/Racing/Leisure which had a steady demand but not many competing games. In the analysis of the 'convenience' factor, one interesting implication for mobile game producers was that there exists a trade off between the ease of initial adoption and the steady sales of a mobile game.