• Journal of the Korean Geotechnical Society
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• v.36 no.10
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• pp.33-39
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• 2020

A geological repository has been considered as an option for the disposal of high-level radioactive waste (HLW). The HLW is disposed in a host rock at a depth of 500~1,000 meters below the ground surface based on the concept of engineered barrier system (EBS). The EBS is composed of a disposal canister, buffer material, backfill material, and gap-filling material. The compacted bentonite buffer is very important since it can restrain the release of radionuclide and protect the canister from the inflow of ground water. The saturation of the buffer decreases because high temperature in a disposal canister is released into the surrounding buffer material, but saturation of the buffer increases because of the inflow of ground water. The unsaturated properties of the buffer are critical input parameters for the entire safety assessment of the engineered barrier system. In Korea, Gyeongju bentonite can be considered as a candidate buffer material, but there are few test results of the unsaturated properties considering temperature variation. Therefore, this paper conducted experiment of soil-water characteristic curve for the Gyeongju compacted bentonite considering temperature variation under a constant water content condition. The relative error showed approximately 2% between test results and modified van-Genuchten model values.

• Journal of the Korean GEO-environmental Society
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• v.12 no.9
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• pp.27-33
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• 2011

In the case of the existing method of underground pipe construction, the difficulty of the bedding compaction of pipe causes reducing the compaction efficiency and the stability of the underground facilities and conclusively damaging the structures. One of the methods to solve these problem is using the flowable fills as a backfill material. Therefore, in this study, numerical analysis of the underground pipe was performed in order to evaluate the behavior of pipe according to backfill mixtures. To estimate the deformation characteristic of the underground pipe, the displacement of the main part of the pipe, ground settlement and vertical earth pressures were measured in different backfill mixtures and maintaining the other conditions constantly. As a result of numerical analysis, using the flowable fills as the backfill material is better than using sand in reducing the ground settlement, the pipe deformation and the vertical earth pressure aspect.

• Journal of the Korean Geotechnical Society
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• v.24 no.12
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• pp.41-52
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• 2008

This paper concerns the load carrying capacity of back-to-back reinforced soil wall for use in roadway and railway construction. Two test conditions, designed with due consideration of the FHW A design guideline, were first developed and a number of cases having different reinforcement lengths were tested under a surchage loading until failure. The results indicated that for cases in which two sides of reinforcements do not overlap, the wall behavior was similar to those of single wall. For cases in which the reinforcements overlap each other, on the other hand, the load carrying capacity of the wall significantly decreased when reinforced with reinforcement layers having lengths less than 50% of the wall height.

• Journal of the Korean Geotechnical Society
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• v.40 no.2
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• pp.81-93
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• 2024

In Korea, numerous large-scale infrastructure construction projects and housing site developments are being undertaken. However, due to limited land availability, sourcing high-quality backfill materials that meet the standards for railroad and road embankment compaction and mechanically stabilized earth (MSE) retaining wall construction poses significant challenges. Concurrently, there has been an increase in structural failures of many MSE retaining walls, attributed primarily to reduced bearing capacity and impaired drainage performance, resulting from inadequate backfill compaction. This study aimed to analyze the structural performance and safety of an MSE retaining wall using recycled soil as backfill. We conducted small-scale model tests utilizing 3D printing technology combined with two-dimensional numerical analysis. The study quantitatively evaluated the MSE retaining wall's performance concerning the recycled soil mixing ratio and reinforcement installation methods. Furthermore, the utility of 3D printing was confirmed through the production of an experimental wall designed to facilitate easy reinforcement attachment, mirroring the conditions of actual MSE retaining wall construction.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.2
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• pp.137-164
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• 2018

The guarantee of the performance of the engineered barriers in a geological repository is very important for the long-term safety of disposal as well as the efficient design of the repository. Therefore, the performance of the engineered barriers under repository condition should be demonstrated by in-situ experiments conducted in an underground research laboratory. This article provides a review of the major in-situ experiments that have been carried out over the past several decades at underground research laboratories around the world to validate the performance of engineered barriers of a repository, as well as their results. In-situ experiments to study the coupled thermal-hydraulic-mechanical behavior of the engineered barrier system used to simulate the post-closure performance of the repository are analyzed as a priority. In addition, in-situ experiments to investigate the performance of the buffer material under a real repository environment have been reviewed. State-of-the art in-situ validations of the buffer-concrete interaction, and the installation of the buffer, backfill and plug, as well as characterization of the near-field rock and the corrosion of the canister materials are, also performed.

• Composites Research
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• v.19 no.4
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• pp.31-38
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• 2006

In this study, effects of curing temperature and autofrettage pressure on a Type 3 cryogenic propellant tank, which is composed of composite hoop/helical layers and a metal liner, were investigated by thermo elastic analysis and composite/aluminum ring specimen tests. Temperature field of a Type 3 tank was obtained from solving the heat transfer problem and, in turn, was used as nodal temperature boundary conditions during the elastic analyses for curing temperature and autofrettage pressure effects. As a result, it was shown that the higher curing temperature was, the more residual compressive stress and tensile stress were induced in composites and metal liner, respectively. On the contrary, autofrettage pressure brought the reduction of these residual thermal stresses caused by cryogenic environments to the tank structure. This tradeoff for curing temperature and autofrettage pressure must be considered in the design and manufacturing stages for a Type 3 cryogenic tank.

• 한국IT서비스학회:학술대회논문집
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• 2002.11a
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• pp.431-438
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• 2002

본 논문은 레거시 시스템을 새로운 시스템 환경으로의 변환 및 통합을 위한 재공학 방법론을 제시하고자 하는 것이다. 기존의 역공학 및 재공학 방법들은 주로 프로그램 소스를 정적 분석하고 유지보수 하는데 중점을 두었으나, 본 방법론은 다양한 추상화 수준에서 역공학 정보를 복구하고, 컴포넌트화 단계를 통해 새로운 시스템으로 진화할 수 있는 절차 및 기법들을 제공한다. 레거시 시스템 컴포넌트화를 위한 방법론은 변환계획 단계, 역공학 단계, 컴포넌트화 단계, 인도 단계의 4 단계로 구성되어 있으며, 본 논문에서는 각 단계에 대한 활동 및 상세 절차에 대하여 기술한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.721-724
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• 2008

무선 센서 네트워크(WSN)를 구성하는 각 센서 노드들의 에너지 관리는 네트워크 전체의 생명주기에 영향을 미치는 요소 중 가장 중요한 요소이다. 센서 노드들은 한번 설치된 이후 짧게는 수개월에서 길게는 몇 년에 걸쳐 동작해야 하기 때문에 배터리에 의존하고 있는 센서 노드들의 에너지를 효율적으로 관리할 수 있는 기술들이 필요하다. Directed Diffusion은 센서 노드에서 수집한 데이터를 네트워크 전체에 브로드캐스팅 하지 않고, 소스(Source)노드로부터 싱크(Sink)노드까지 강화(Reinforce)된 경로를 통해서만 데이터를 전송하여 경로 이외의 노드들의 불필요한 에너지 소모를 줄일 수 있는 라우팅 프로토콜이다. 그러나 기존의 Directed Diffusion에서는 전송 경로 상에 장애가 발생했을 경우 싱크에서 전송한 익스플로러터리 패킷을 기다려야 하며, 장애가 발견되고 재전송되기 전까지 전송된 데이터는 무의미한 데이터가 된다. 본 논문에서는 앞서 언급된 Directed Diffusion의 장애 경로 복구의 문제점을 보완하기 위해 Fast Repair(FR)를 제안한다. FR은 데이터 전송 경로 상에 장애 발생 시 데이터를 재전송 하고 경로를 재설정하는데 효율적이며, 성능평가 결과에서도 기존의 Directed Diffusion에 비하여 향상된 성능을 나타내고 있다.

• The Microorganisms and Industry
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• v.16 no.2
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• pp.26-33
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• 1990

유전공학 제품을 생산하기 까지에는 여러 공정개발 단계를 거쳐야 하는데 크게 나누어 유전자 재조합기술 개발단계와 생물공정기술 개발단계로 나눌 수 있다. 유전자 재조합 기술에 의해 얻어진 생산균주로부터 발효및 분리&정제공정을 거쳐 대량생산에 이르기까지 필요한 기술을 생물공정기술이라 일컫고 있는데 본고에서는 유전자재조합 미생물의 발효공정에 촛점을 맞추어 재조합 미생물의 재조합 단백질의 분비기술, 고정화재조합 미생물을 이용한 생산기술 및 고농도 배양기술 등 재조합 미생물 발효공정기술의 최근 연구동향에 대해서도 고찰해 보고자 한다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.195-196
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• 2023

In this study, the mechanical properties, alkali-silica reaction(ASR) expansion and residual mechanical properties after ASR of waste glass fine aggregate(GS) mortar according to mineral mixture were evaluated. As a result, it was found that the mineral mixture reduces the ASR expansion. However, mechanical properties and residual mechanical properties have decreased.