• 대한수학회보
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• 제57권1호
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• pp.219-244
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• 2020

In this paper, we approximate the solution of the coupled nonlinear Schrödinger equations by using a fully discrete finite element scheme based on the standard Galerkin method in space and implicit midpoint discretization in time. The proposed scheme guarantees the conservation of the total mass and the energy. First, a priori error estimates for the fully discrete Galerkin method is derived. Second, the existence of the approximated solution is proved by virtue of the Brouwer fixed point theorem. Moreover, the uniqueness of the solution is shown. Finally, convergence orders of the fully discrete Crank-Nicolson scheme are discussed. The end of the paper is devoted to some numerical experiments.

• 자원ㆍ환경경제연구
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• 제9권3호
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• pp.563-587
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• 2000

A program of ecosystem conservation fund was proposed by the Ministry of Environment in Korea and has been supposed to come into force in early 2001. However, currently the program is withheld because there are strong objections to it for several reasons. The prime purpose of this paper is to analyze the reasons and problems involved in the program, to suggest some guidances to revise the program, and to design a new program by using a multiattribute index based on environmental significance. We found that there are two major problems of the program: first, inequity in choosing those whom the fund are levied on; second, irrationality of the way the fund are imposed. The paper also provides a simulation study to analyze the effects of four scenarios concerning feasible alternatives. We argue that natural resource damages caused by development works cannot be fairly prevented by the existing environmental impact assessment system only and should be used in harmony with the new system.

• 오토저널
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• 제4권2호
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• pp.58-68
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• 1982

It is well known to diesel engineers that the heat release pattern is one of the most important factors affecting engine performance. Thorough research in heat release pattern has materially helped the progress in high-speed diesel engine development . This paper is based on the research conducted at KAIST and Daewoo Heavy Industry last year. The purpose of this paper is to determine the heat release pattern in combustion chamber of MAN M type, the famous low-noise engine. Thermodynamic cycle simulation was performed using Whitehous-Way's heat release pattern with modified coefficients and Annand's heat transfer model. Instantaneous temperature and pressure of gas in cylinder could be determined by the numerical solution of simultaneous equation of mass conservation, equation of energy conservation, and state equation of ideal gas. Calculated results were compared with measured values in some details emphasizing upon the factors affecting rate of heat release. The agreement was fairly good and revealed why M type should have lower burning velocity at the early part of combustion in spite of high injection rate. Additional results by parametric studies were given in relation to fuel injection conditions for further application to engine development.

• 한국문화재보존과학회:학술대회논문집
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• 한국문화재보존과학회 2004년도 제20회 발표논문집
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• pp.104-108
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• 2004

Species and anatomical characteristics of twenty-seven straw shoes (around AD 500s-600s) of Baekje Kingdom, excavated at Gwanbukri and Goongnamji relics of Baeje Kingdom, were examined. The shoe tissues were macerated and examined under microscope. They were identified as Typha spp (cattails), not any of straws such as rice. Cattails, a perennial glass, grow in low and swamp places. Cattails are not known as one of major raw materials for straw shoes. The cattail fibers are not as strong as those of rice straws, common raw materials for ancient shows.

• 설비공학논문집
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• 제12권10호
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• pp.879-885
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• 2000

It is a serious subject for energy conservation to prevent the energy loss caused by mixing of heated and cooled air jets in a building which two types of air-conditioning systems are adopted in perimeter and interior zone. The purpose of this paper is to clarify the quantitative and qualitative mechanisms of the mixing loss and to propose preventive methods for it. In this paper, by using the dynamic heat load calculation method, heat extraction loads of a typical office building in Pusan are calculated. According to the results, numerical simulation based on the computational fluid dynamics were peformed in order to measure the mixing loss in physical size HVAC system. Then, the distributions of air temperature and velocity are analyzed in order to grasp the relations by setting temperature differences influence on the mixing loss.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권11호
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• pp.5449-5464
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• 2018

Recent works have validated the possibility of reducing the energy consumption in wireless heterogeneous networks, achieved by switching on/off some base stations (BSs) dynamically. In this paper, to realize energy conservation, the discrete time Markov Decision Process (DTMDP) is developed to match up the BS switching operations with the traffic load variations. Then, an asynchronous decision-making algorithm, which is based on the Bellman equation and the on/off priorities of the BSs, is firstly put forward and proved to be optimal in this paper. Through reducing the state and action space during one decision, the proposed asynchronous algorithm can avoid the "curse of dimensionality" occurred in DTMDP frequently. Finally, numerical simulations are conducted to validate the effectiveness and advantages of the proposed asynchronous on/off strategies.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2008년도 추계학술발표논문집
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• pp.205-213
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• 2008

• 한국문화재보존과학회:학술대회논문집
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• 한국문화재보존과학회 2004년도 제19회 발표논문집
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• pp.40-46
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• 2004

• 헤리티지:역사와 과학
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• 제46권3호
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• pp.194-210
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• 2013

유지(油紙)는 선조들이 사용했던 생활필수품으로 종이에 기름을 먹인 전통적인 가공지이다. 그러나 현재 유지(油紙)에 대한 정확한 연구가 부족한 실정이므로 유지의 문헌사적 연구를 통해 유지의 기원과 명칭, 용도, 제작기법에 대하여 조사하였다. 고문헌으로 확인된 유지의 기원은 "고려도경(高麗圖經)", "고려사(高麗史)"의 내용을 통해 고려시대로 추정하였으나, "삼국사기(三國史記)"와 "일본서기(日本書紀)"에 나타난 기름과 종이의 기록으로 보아 7세기경부터 유지제작이 이루어졌을 가능성도 배제할 수는 없다. 조선시대는 "조선왕조실록(朝鮮王朝實錄)", "일성록(日省錄)", "승정원일기(承政院日記)" 기록을 통해 유지의 명칭과 사용법에 대해 조사하였으며, 의궤류와 "탁지준절(度支準折)" 등 기타 여러 분야의 고문헌 내용을 바탕으로 절가와 용도, 제작재료에 대하여 조사하였다. 조선시대의 문헌 조사결과 유지는 방수, 방습, 투명성 등의 특성으로 인해 각종 생활 용품으로 사용되었으며, 그 용도와 제작과정에 따라 다양한 명칭으로 불리기도 하였다. 본 연구를 통하여 조선시대 유지 관련 문헌조사가 이루어졌으나 전통 유지 복원에 관한 연구는 아직도 부족한 상태이다. 그러므로 현재 남아 있는 유지 유물조사연구와 전통 유지 샘플 제작 실험, 또한 유지를 제작하고 있는 장인들에 대한 사례 조사가 병행되어 전통 유지 연구가 이루어져야 할 것으로 생각된다.

• 박물관보존과학
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• 제15권
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• pp.122-137
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• 2014

국립중앙박물관 소장의 실록함 ^K976은 조선왕조 선조대의 실록을 보관했던 함으로 장방형 몸체에 뚜껑이 달려있고 표면 전체에 검은색 옻칠이 되어있다. 실록함은 모서리 결구 부분의 짜임이 벌어지고 판재들이 밖으로 휘어지면서 심하게 변형되어 있었고 함의 몸체 상단부의 백골이 부분적으로 결실된 상태였다. 여기에 더하여 뚜껑에는 길이 방향으로 큰 폭의 균열이 발생되어 있었다. 표면의 칠은 곳곳이 들뜨거나 탈락되어 목제 백골이 겉으로 드러난 곳이 많았고 뚜껑을 연결하는 고리쇠 1개가 결실된 상태였다. 국립중앙박물관 보존과학부는 2013년 실록함의 수리 복원 작업에 착수하였으며 이에 앞서 실록함의 구조 양식, 손상 상태, 목제 백골 ^白骨의 수종 분석, 옻칠 기법 등에 대한 조사를 실시하였다. 그 결과 실록함의 목제 백골 재료가 피나무라는 것, 또 실록함 표면에 골회칠 ^骨灰漆 → 종이심 ^紙心, 토회칠 ^土灰漆, 연매 ^煙煤 혼합 흑색칠 → 옻칠이 순차적으로 도장되어 있다는 것을 확인할 수 있었다. 이 실록함은 전통 목칠공예 기술과 재료를 적용한 전면적인 수리 복원을 통해 그 본래의 모습을 되찾게 되었고, 이후 국립전주박물관 역사문화관 개편 전시에서 중요한 전시물로 활용되었다.