• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.368-368
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• 2016

점착성 유사는 응집현상을 통해 크기와 밀도를 바꾸고 이에 따라 부유 및 이동에 큰 영향을 미치는 침강속도가 지속적으로 변화한다. 따라서 점착성 유사의 거동을 이해하기 위해서는 응집현상에 대한 고려가 필수적으로 이루어져야 한다. 현재까지 이루어진 응집현상 모형은 크게 Population balance equation type 모형(PBE)과 Floc growth type 모형(FGM)으로 나뉜다. PBE 모형은 점착성 유사의 입도분포를 모의할 수 있는 장점이 있는 반면에 닫힌 계에서 질량보존을 만족시키지 못하는 단점을 가진다. FGM 모형은 간단한 식을 통해 질량보존을 만족시키고 수치적으로 효율적인 모의를 할 수 있는 반면 입도분포를 모의할 수 없는 단점을 가진다. 이러한 장단점으로 인해 PBE 모형은 유사이동모형과 결합되어 이용된 사례가 없으며 FGM 모형은 유사이동모형과 결합되어 평균적인 점착성 유사의 거동만을 모의하는 연구에 이용되었다. 본 연구에서는 Stochastic floc growth type 모형(SFGM)의 개발에 따라 이해할 수 있는 점착성 유사이동의 특성과 이를 유사이동 모형과 결합시키는 방향에 대해 검토한다. 현재까지 진행된 연구 결과를 분석하면 SFGM은 질량보존을 만족시키면서도 점착성 유사의 입도분포를 모의할 수 있는 장점을 가지는 것으로 판단된다. 특히 난수발생의 단계에서 적절한 확률분포형을 선정하고 확률매개변수의 보정이 이루어지는 경우에는 높은 정확도를 가지는 입도분포 모의가 가능하다. 가는 모래를 대상으로 하는 비점착성 유사의 경우에는 추계학적인 유사이동 모형의 개발이 활발히 이루어져 왔다. 개발된 모형은 실제 측정값에 적용되어 다양한 학술적 가능성을 보여왔다. 따라서 SFGM의 개발이 점착성 유사의 이동모형과 결합되는 경우에는 점착성 유사가 지배적인 다양한 환경에서의 거동 특성을 이해할 때 매우 유용할 것으로 판단된다. 응집모형은 난류의 강도에 지배적인 영향을 받으며 유사의 입경 및 밀도 변화를 계산한다는 점을 고려할 때 유사이동 모형 역시 난류 강도에 대한 정보를 계산할 수 있는 지배방정식을 필요로 한다. 향후 개발될 추계학적 점착성 유사의 이동모형은 난류에 대한 정보, SFGM의 결합 등을 필요조건으로 가진다.

• Journal of Conservation Science
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• v.37 no.5
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• pp.505-515
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• 2021

In this study, we evaluated the slope stability of the Pohang Daljeon-ri columnar joint (Natural Monuments # 415) and calculated the maximum energy, jumping height and moving distance of rockfalls using a simulation. Based on the results, we established the range of rockfall risk. The slopes of the Pohang Daljeon-ri columnar joint have dip directions of 93.79°, 131.99°, 165.54° and 259.84° from left (SW) to right (NE). Furthermore, they have a fan-like shape. The Pohang Daljeon-ri columnar joints are divided into four sections depending on the dip direction. The measurement results of the discontinuous face show that zone 1 is 125, zone 2 is 261, zone 3 is 262, zone 4 is 43. The results of slope stability analyses for each section using a stereographic projection method correspond to the range of planar and toppling failure. Although it is difficult to diagnose the type of failure, risk evaluation of currently falling rocks requires further focus. The maximum movement distance of a rockfall in the simulation was approximately 66 m and the rockfall risk range was the entire area under slope. In addition, it is difficult to forecast where a rock will fall as it rolls in various directions due to topographic factors. Thus, the installation of measures to prevent falling is suggested to secure the stability based on the results of the rockfall simulations and its probabilistic analysis.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.588-593
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• 2006

자연하천은 일반적으로 만곡수로나 사행수로 형태를 보이고 있으며, 직선수로에서와 달리 원심력에 기인한 이차류 영향을 받게 된다. 이차류에 의해서 수면에서는 만곡부 바깥쪽으로, 하상에서는 만곡부 안쪽으로의 흐름특성을 보이게 된다. 만곡부 안쪽으로 가해지는 하상 전단응력에 기인하여 하상에서의 입자가 만곡부 안쪽으로 이송되며, 결과적으로 만곡부 안쪽에는 점사주가, 바깥쪽에는 소(pool)가 생성된다. 또한 지형경사의 생성으로 입자에 가해지는 중력효과도 변화된다. 따라서 이와 같은 자연하천의 흐름과 하상변동을 수치모의 하기 위해서는 만곡부 이차류 특성을 고려한 모형이 필요하다. 본 연구에서는 수심 적분된 흐름방정식과 하상토 보존방정식 (Exner equation)을 이용한 하상변동을 위한 비연계 수치모형을 위해서 하상토 보존방정식의 유한요소 알고리즘을 개발하였다. 하상토 보존방정식은 흐름 특성에 따른 평형 유사량의 공간변화율을 이용하여 일정 기간 동안의 하상 변화량을 계산한다. 이 때 이차류에 의한 하상 전단응력의 편각 및 지형경사 변화에 따른 실제 입자의 이송방향을 보정하여 평형 유사량이 계산된다. 이러한 보정식을 적용시키기 위해서는 유속성분의 공간변화량 및 지형경사의 공간성분이 필요하다. 유한요소법은 연속성 변수를 이산화시켜 근사해를 구하는 수치기법의 일종이기 때문에, 요소망이 불규칙적으로 구성되었을 경우 임의의 절점에서 연속성을 지닌 변수의 공간변화율을 계산하는데 어려움이 있다. 따라서 본 연구에서는 평형 유사량 계산 시에 절점이 아닌 요소 내부에서 평형 유사량을 계산하는, 하상토 보존방정식의 새로운 유한요소 알고리즘을 개발하고, 새로운 알고리즘을 적용시킨 수치모형의 검증을 행하였다. 경계조건 알고리즘의 검증으로 위해서 Soni 등 (1980)이 행한 상류 유입 유사량에 따른 하상변동을 수치 모의하고 실험치와 비교하였으며, Sutmuller와 Glerum (1980)이 수행한 만곡수로에서의 하상변동을 모의하고 실험과 비교하였다. 새로운 알고리즘을 적용시킨 하상토 보존방정식의 유한요소 수치모형의 결과는 매우 안정적이며, 실험과 매우 유사한 결과를 얻을 수 있었다. 본 수치모델은 현재 균일한 입자의 하상토만을 고려하므로, 입자분급이나 하상 장갑화 현상 등은 무시한다.

• Journal of the Korean Society for information Management
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• v.27 no.1
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• pp.185-206
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• 2010

Since core scholarly journals have been digitalized, demands on the perpetual access and long-term preservation of subscribed digital information resources by libraries are increasing. Various institutions and organizations have performed the preservation activities of digital scholarly resources for the purpose of responding those demands. This paper illustrates the National Digital Archive(NDA) system proposed and developed by KISTI and discusses on the NDA strategies which aim to improve the usability of archived journal articles. In addition, NDA strategies of KISTI have been compared with those of international researches and the economic validity of NDA has been verified by analyzing NPV, BCR and IRR. Legal system for improving the application of the archived data should be studied next and high value-added data services have been suggested as our future studies in the final section.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.2
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• pp.20-33
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• 2020

This study aims to examine the trends in the preservation of urban public parks with a focus on the international movement to acknowledge and preserve the heritage value of urban parks. First, the background in which the concept of "historic urban park" first appeared internationally, as well as the current situation were investigated. Then, the cases of the United Kingdom (UK), the United States (US), and Japan, all of which are already preserving and managing urban public parks, were analyzed. In the ICOMOS-IFLA Document on Historic Urban Public Parks, the International Council on Monuments and Sites (ICOMOS), which is a group of specialists dedicated to the conservation and management of cultural heritage, mentions that it is necessary to maintain the social, intangible, aesthetic, ecological, and civic values of historic urban public parks. In addition, according to ICOMOS, it is necessary to preserve elements of parks, such as space composition, topography, light, and environment. The UK, the USA, and Japan have their own unique characteristics for the background of preserving urban parks, the preservation system, the selection of parks to be preserved, and the elements to be preserved within the park. The UK has categorized parks into certain types from each period and has tried to preserve the common elements in each type. The US has selected the parks to preserve by determining the meaning of the parks itself considering multiple aspects, embracing not only the physical form of the parks, but also the culture, monumentality, and social values. Recently, Japan began the preservation of historic urban parks as a matter of policy and started to implement a preservation policy by investigating modern parks that are believed to be worth preserving. Specialists in cultural heritage preservation have argued that the method of preservation of historic urban parks must differ from that of other parks or gardens. Nonetheless, observing cases in these three countries showed that, regardless of their administrative and legal systems regarding cultural heritage and urban public parks, their policies were still limited to preserving only the physical elements of parks. The direction and methodology for the preservation of historic urban parks must be developed further and elaborated upon in terms of the evolving concept and definition of heritage. Urban parks are where various historic values are accumulated, connoting historical meanings dealing with the memories of the parks and the urban dwellers. This study found that, worldwide, park management has been carried out in a way that the historic values of parks are respected and preserved. This global trend in preserving the historic values of urban public parks has significant implications for the management of urban public parks in Korea that are being formed and renewed repeatedly.

• The Korean Journal of Archival Studies
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• no.52
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• pp.5-37
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• 2017

In consideration of the drastic transformation of records management environments, this study aims to suggest the directions for redesigning the electronic records management policies at a national level. First, it clarifies the four implicit objectives of electronic records management policies since the 2006 amendment of the Public Records Management Act, such as comprehensiveness for ensuring the appropriate management of any type of digital records, digital-friendly processes for records management, proper management for guaranteeing the evidential value of digital records, and long-term preservation of digital records. Second, it examines the challenging environmental factors in the areas since 2006. Third, it reviews the achievement of the policies as well as failures based on analyzing the policy documents and data from the National Archives of Korea. Fourth and finally, it suggests core areas and directions for redesigning the electronic records management policies, emphasizing the inclusiveness for data-type electronic records.

• Journal of Conservation Science
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• v.37 no.5
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• pp.516-524
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• 2021

The 'artist's intention' plays an important role in the conservation process of contemporary art. Accordingly, the information on artworks owned by the artist, their bereaved family members, and foundations that have decision-making power is important. The artist's interview is the kind of data that can clear 'artist's intentions' to ensure reliable conservation treatment can be carried out even after the artist's death. Therefore, this study attempted to use information from the artist's interview on the type of wood in the manufacture of the filler required for lifted and separated bark conditions in the conservation process of wooden artwork in the National Museum of Modern and Contemporary Art. While the conservation treatment resulted in the stable preservation of the bark of artwork, an analysis of the wood confirmed that the information in the artist's interview was not true. Consequently, we suggest that attention must be paid toward the information provided by artist, their bereaved families, etc. Based on the result of this study, this is also expected to help preserve upcoming artworks with similar bark conditions.

• Korean Journal of Heritage: History & Science
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• v.44 no.4
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• pp.154-171
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• 2011

Assessing values in establishing conservation principles has been at the heart of discussions for the last twenty years since conservation has been recognised as a social process to include various kinds of stakeholders for making a rational decision rather than a single scientific activity by a small group of experts. Such perception makes values attributed to cultural heritage important in deciding the reason why, the way how to, and the thing what to conserve making value assessment become crucial theme to understand and developing value-based conservation process. However heritage values, the way of assessing them, and establishing value-based conservation principles have been less studied in Korea. This thesis aims to initiate studies of heritage values and encourage discussion for setting out value-based conservation principles. It has three main chapters: 1. to analytically review previous studies on value assessment to redelineate various kinds of values which can be attributed to Korean cultural heritage; 2. to examine affecting factors in assessing values and significance, which are authenticity and historical and cultural dimension of value assessment; 3. to develop a process to establish value-based conservation principles. This study left several areas to be developed in future studies: 1. deeper understanding of various kinds of values from local perspective taking actual cases; 2. addressing problems in compromising conflicting values and providing solution to conserve all attributed values withing devaluing certain aspects of values; 3. providing guidance for practicing value - based decision - making process and setting out regular training opportunities for heritage - related professionals.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.524-528
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• 2008

도류제 완성 후에 대한 100년 빈도 홍수시의 흐름(유향과 유속)을 기초로 하여 수치모형실험 결과의 일례를 그림에 나타내었다. 초록에는 오염물질 확산 수치모형실험결과를 시간별로 나타내지안했지만, 오염물질 확산에 대한 수치모형실험의 일반적인 결과를 평가하면 아래와 같다. 우선 흐름은 임랑해수욕장 방향으로 형성되고 청정지역인 방향에서는 남측도류제 설치전보다 복잡한 와류가 형성되어 청정지역 방향으로의 흐름은 미약하다. 모델하천의 빈도별 유출량이 증가함에 따라 큰 변화는 없고, 흐름은 모델하천 하구부 전면해역의 외해 방향으로 형성되며 빈도에 따른 흐름방향의 변화는 거의 없다. 보존성 오염물물 확산 계산 결과를 보면 평수시의 오염물질 영향범위는 양안에 도류제가 완성됨으로 인해 확산이 차단되어 도류제 내부의 오염물의 농도가 가중되고 도류제 전면해역으로의 오염물질의 확산범위가 확대됨을 알 수 있다. 모델하천의 빈도별 유출량이 증가함에 따라 오염물질의 농도가 일정하게 유지될 때 초기유출(3시간)에는 도류제 전면해역의 외해 방향으로의 오염물질 확산이 가속화 되며, 확산범위도 점차 확대된다. 오염물질의 농도가 감소하여 모델하천으로 부터의 오염물질 배출이 감소할 경우(15-24시간)는 오염물질 농도가 점차적으로 저감되며 청정지역으로 확산이 지연됨을 알 수 있다.

• Journal of Conservation Science
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• v.7 no.2
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• pp.60-67
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• 1998

The effects of moisture content (MC) and diffusion period on the diffusion of boron from borate rod through Pinus densiflora and P. koraiensis were investigated as a preliminary research of integrated remedial treatment for heritage wooden structures using borate rod. After equilibrating MCs of samples (15, 25, and 40%), borate rod (1,000 mg) was inserted into the sample, and stored for diffusion of boron at room temperatures ($23^{\circ}C$) for 2, 4, 8, and 12 weeks. Wafers were serially cut at constant intervals from rod treatment point and the boron penetration through longitudinal and transverse direction was measured by staining with boron indicator. For boron diffusion, MC above fiber saturation point was needed, and the diffusion rates increased with time. The fastest rates of diffusion were observed in longitudinal direction, followed by the radial and then the tangential direction. The rates of diffusion in all directions were the fastest in P. koraiensis. In P. densiflora, the diffusion rates through heartwood was faster than that in sapwood in longitudinal direction and vice versa in transverse direction. Based on the best result of this study, optimal space between rod insertion points could be recommended as follows; approximately 120 mm for P. koraiensis and heartwood of P. densiflora, 60 mm for sapwood of P. densiflora in longitudinal direction, and approximately 30 mm for all species tested in transverse direction. However, the effect of rod size and long-term exposure for diffusion on boron movement should be fully investigated for the accurate evaluation of optimal space between rod holes.