• The KIPS Transactions:PartC
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• v.9C no.6
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• pp.817-822
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• 2002

We want to find a timestamping method which improves efficient performance and have high-level security to send secured messages in the digital signature and the law of e-commerces. Our paper shows a H-binary tree of time stamp to use a time stamp protocol with high suity and performance in the packets of sending messages. We implement and analyze the protocols, show to compare with previous RSA methods. Our proposed protocol has O(log n) time complexity and high-performance.

• Korean Journal of Remote Sensing
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• v.11 no.1
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• pp.1-17
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• 1995

Using remotely sensed data(MOS-1) and other spatial data such as aerial photos and topographic maps, 10 kind of thematic layers were prepared with Arc/Info system for watershed management of Nam Khane River, northern part of Laos. The characteristics of landuse distribution of some criteria which like village, sub-basin, elevation and slope were clarified by overlaying each layer. Therefore, statistic data including shifting cultivation area were produced from database layer. Through the manipulation of some data of each layer, suitable area for permanent paddy cropping converted from the fallow and shifting cultivation area was extracted.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.298-298
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• 2019

과거에 경험하지 못한 집중호우가 빈번하게 발생하고 규모가 큰 태풍의 내습이 발생하고 있다. 2018년 7월23일 발생한 라오스 댐붕괴 발생으로 인해 6,600명의 이재민이 발생하였으며, 2008년 중국 쓰촨성 지진에 의해 댐 수백개가 균열이 발생하는 위험한 상황에 이르는 등 댐 붕괴에 따른 대규모 재난의 위험상황은 항시 존재하고 있다. 는 상황에서 댐의 붕괴에 대한 많은 연구가 진행되었다. 이러한 댐 붕괴 상황에 대한 대비책으로 저수지 댐의 안전관리 및 재해예방에 관한 법률 제3조와 자연재해 대책법 제37조에 총저수용량 30만톤 이상의 저수지에 대해 비상대처계획 수립을 하도록 되어 있다. 최근 경주와 포항에서 발생한 규모 5.4이상의 지진이 발생하여 지진에 의한 재난의 위험이 가중되고 있는 상황에서 지진에 의한 댐붕괴에 대한 적절한 시나리오와 분석이 필요하다. 지금까지의 지진붕괴에 의한 EAP의 작성은 단순히 만수위 상태에서 댐의 붕괴시간이 급격히 붕괴되어 범람되는 분석을 하였다. 그러나 지진에 의한 댐의 붕괴에 이르는 지진의 규모는 댐 주변의 건축물, 교량, 심지어 대피소도 붕괴 및 범람에 안전할 수 없는 상황에 이르게 될 것이다. 그러나 현재의 EAP는 단순 범람만을 통해 위험도를 나타내는 것으로 작성되어 있어 이에 대한 수정이 필요하다. 본 연구에서는 지진에 의한 댐 붕괴 EAP 작성시 고려되어야 할 건물의 노후도, 교량, 공공시설물 등이 붕괴될 위험을 판단하고 이에 따른 범람도면의 작성과 시나리오가 작성되어야 한다. 이를 위한 행정안전부에서 제시된 지진 시 댐 붕괴 조건에서 고려되어야 할 시나리오의 구성요소에 대해 검토하였다.

• Solar Energy
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• v.11 no.1
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• pp.16-26
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• 1991

This paper studies development of a solar thermosyphon hot water system which is suitable to korean climate and life style, to save energy consumed for domestic water heating. The system consists of two flat plate collectors(or three flat plate collectors) connected in parallel and a storage tank of 300 liter capacity with heat exchanger and the optimum system was designed through the comparative measurements of five different storage tanks. The developed system manufactured with domestic materials were installed in residential buildings in seven cities(Seoul, Pusan, Taegu, Kwangju, Taejeon, Kangneung, Cheju) for demonstration and field test and results show possibility for commercialization.

• The Journal of Engineering Geology
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• v.30 no.4
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• pp.497-514
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• 2020

This study investigated the causes of large-scale ground subsidence in the upper part of mining cavities of the Samdo limestone mine, Samcheok city, Gangwondo, Korea. Geological and electrical resistivity surveys were undertaken on the collapsed slope of the mountain and in the mine tunnel where subsidence occurred, with geotechnical evaluations and numerical analysis. It is concluded that wide mining cavities, with irregular pillars in unstable rock masses hosting discontinuities, weathered over time, resulting in subsidence occurring along a fault plane due to increasing ground stress.

• Journal of Korean Society of Transportation
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• v.23 no.1
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• pp.33-44
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• 2005

Railroad crossing crashes are fewer than road crashes, but with regard to crash severity, they can be serious injury crashes. There should be, therefore, enormous efforts to increase the safety of railroad crossings. The objective of this paper is to identify and understand factors associated with railroad crossing crashes. Statistical models are used to examine the relationships between crossing accidents and geometric elements of crossings. The results show the Poisson model is the most appropriate method for the crossing accidents, because overdispersion was not observed. This study identifies seven significant factors associated with railroad crossing crashes through the main and variant models. With regard to explanatory factors on crossing safety, the total traffic volume, daily train volume, presence of commercial area around crossings, distance of train detector from crossings, time duration between the activation of warning signals and gates, crossing types, and speed hump were found to affect the safety of railroad crossings.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.695-702
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• 2006

In GIS-based Spatial Decision-making Support System (SDSS), the Boolean logic by conventional simple overlay method contains two problems. One is losing lots of information in analysis process, the other is unable to reflect of weighting values between evaluated items. Therefore, evaluation system as Analytic Hierarchy Process (AHP) needs to improve these problems effectively. The purpose of this study is to provide the benefit of AHP method and GIS spatial analysis in site analysis for crop cultivation. First, the weighting value of AHP for topography, distribution grade of water, property of soil and slope items are evaluated throughout survey to experts of soil, crop and agricultural management fields. On the basis of these weighting value of AHP by items, site suitability analysis for black raspberry cultivation is performed. To estimate the benefit of AHP method, the current cultivating map of black raspberry is constructed in Ssangchi-myeon district. In comparison with site analysis of Boolean logic, site analysis of AHP method shows more realistic.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.1
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• pp.40-50
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• 2016

A BIM, which is being applied actively to the construction and civil construction industries, is a technology that can maximize efficiency of various sectors from initial planning and design, construction, and maintenance, to demolition; however, it is in the introductory phase in the field of domestic landscaping. In order to introduce and promote BIM in the field of landscape design, this study developed a prototype of a library and template and analyzed the performance of trial application. For the development of a prototype, annotations and types were analyzed from floor plans of existing small parks, and components of landscape template were deduced. Based on this, play facilities, pergola, and benches were madeintofamily and templates, making automatic design possible. In addition, annotations and tags that are often used in landscape design were made, and a 3D view was materialized through visibility/graphic reassignment. As for tables and quantities, boundary stone table, mounding table, summary sheet of quantities, table of contents, and summary sheet of packaging quantities were grouped and connected with floor plans; regarding landscaping trees, classification criteria and name of trees that are suitable for domestic situations were applied. A landscape template was created to enable the library file format(rfa) that can be mounted on a building with BIM programs. As for problems that arose after the trial application of the prepared template, some CAD files could not be imported; also, while writing tables, the basis of calculation could not be made automatically. Regarding this, it is thought that functions of a BIM program and template need improvement.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.3
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• pp.477-485
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• 2018

To control manage environmental load during construction work, it is required to ascertain an accurate quantity for materials those are using during the construction. In construction industrial nowadays, especially on design part, there are lots of mistakes occurred on quantity take-off between plan documents and actual work. That mistakes are caused by omission of design items, overcount because of interference each materials or simple calculate error. Besides, in case of a construction project, engineers are impossible to design perfectly due to a lot of invalid variable in a construction site. Thus, design errors and changes occur frequently in the process of construction work or design due to such unclear elements. And in case of LCA assessment based on 2D design, there is difficult for an engineer who is in charge to calculate the volume of materials manually using drawings and relevant specifications. This study is aimed for examining and verifying a high reliable method of evaluating environmental load which is useful in construction process through comparing LCA analysis. In addition, this study provides the method of calculating the volume of materials and LCA assessment in working on the basis of 2D design, using the specifications which is used for LCA evaluation, and possibility of utilizing the LCA assessment by introducing BIM design technic to improve the former problem through comparing and analyzing the previous method with 3D-based evaluation process.

• Journal of the Korean Institute of Landscape Architecture
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• v.46 no.3
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• pp.117-129
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• 2018

With the changing of social needs and paradigms, citizens are concerned about aesthetic and cultural community gardens from productive urban farms in Korea. It is still difficult, however, to cultivate a beautiful garden with a community to design, install and manage it. Therefore, this study analyzed the community garden design guidelines of other countries to derive the characteristics and implications. The research method analyzed six guidelines for community garden design in the UK, Canada, the USA, Australia and Japan. As a result of the study, most community garden design guidelines are opened freely via on-line service. The guidelines are composed with chronological processes such as intro, site selection, design, construction and maintenance. The introduction section treats definition, purpose, meaning, efficiency and success factors for community gardens. Site selection emphasizes site conditions (soil, light, shadow, water, etc.), landholding and insurance. The design section, however, lacks adequate drawings and case images. These guidelines offer little explanation with few illustrations and sentences. Construction sections explain about plantings, facilities, expense and details. The maintenance guidelines of community gardens contain how to control members, funding, harvesting, pests and plants. In addition, some guidelines include vandalism, organic cultivation methods, recording and advertisement. Lastly, the appendix contains a variety of checklists, administrative documents, guidelines, drawings, and contacts. This study will help understand the trends and characteristics of overseas community gardens design guidelines so as to also supply directions for guidelines to be introduced in Korea.