• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.814-817
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• 2005

Today recycling has been one of the most important Issues In industry as it is required to save the limited amount of natural resources and to keep the environment green. In spite of many efforts to increase recycling rate in industry, however, the practical solutions are very limited. The difficulties are caused by the existence of many parts made of diverse materials and their inevitably complicated assembly structures to satisfy different needs. This paper represents a study on the disassembly sequence generator system for parts recycling. With disassembly costs and revenues, the optimum disassembly sequence can be found with a linear programming.

• Korea journal of population studies
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• v.18 no.1
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• pp.1-39
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• 1995

한국의 농촌위기를 농업생산과 농민생활의 기초적 조직단위의 차원에서 살펴보면 문제의 핵심이 가족농의 재생산체계의 와해에 있음이 드러난다. 농촌가구의 재생산주기 단계별 분포를 볼 때, 이른바 축소기 및 해체기에 있는 가구의 비율이 급속히 증가하고 형성기 및 확대기에 있는 가구의 비율은 급속히 감소함에 따라 한국의 가족농체제는 그 미시조직적 기반이 와해되어 가고 있음이 드러난다. 아울러 가족 재생산 주기의 각 단계인 양육 및 교육, 농가경제 계승과 혼인, 노후 부양 등의 과정에서 동시적으로 나타나고 있는 혼돈과 단절이 농촌의 기초조직인 농가의 존속 자체를 어렵게 만듦으로써 정상적 농가 없는 농촌의 총체적 퇴행이 나타나고 있다. 종합적으로 말해 가족농 재생산체계가 그 양적인 측면과 질적인 측면 모두에서 심각한 위기상황에 처해 있는 것이다. 본 연구의 결과에 기초해 볼 때, 한국 농촌의 현실은 기초 생산,생활조직의 차원에서 급격한 해체는 진행되고 있으나 적절한 재구조화(restructuring)는 이루어지고 있지 못한 상황이다. 따라서 생산조직 차원에서의 농촌문제의 대처는 기존 농가 재생산 주기의 붕괴에 관한 다양하고 즉각적인 대증요법을 동원해 가족농 해체의 부작용을 최소화시키는 한편, 보완적 조치로서 새로운 협업적 또는 기업적 경영체계의 확립에 관계된 사회적 필요조건들을 충족시키는 것이어야 할 것이다.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2023.11a
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• pp.87-88
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• 2023

서해안 최고의 동백정해수욕장과 마량리 동백나무숲은 1970년대 오일쇼크 이후 에너지 자립을 위해 발전소를 건설하면서 사라졌다. 그 당시 준공된 화력발전소는 전력공급 이라는 소임을 완수하고 2021년 부터 동백정의 아름다운 옛 모습 그대로 지역주민에게 돌려 주기위한 친환경 사업으로 발전소 철거공사를 시작, 동백정 복원공사를 추진 하기로 했다. 고층 및 중량물의 건축물 및 구조물을 안전하게 해체하기 위해서는 국내 최초 발전소 철골구조물에 대한 발파·전도공법을 채택 하였다. 철거작업은 고위험 공종으로 참여 주체인 발주자, 설계자, 감리자, 시공자 및 근로자 전 계층의 참여로 사전 위험성평가를 통해 근원의 위험요인 발굴 및 안전대책 수립, 수립된 안전대책 100% 이행을 통해 무재해 준공 달성 하기를 기대한다.

• Journal of Radiation Protection and Research
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• v.37 no.4
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• pp.202-207
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• 2012

The radioactivity inventory significantly affects all steps of decommissioning projects including planning, cost estimation, risk assessment, waste management and site remediation. The decommissioning project of the KRR-2 was completed in 2009 and a large amount of activated concrete waste was generated. The bioshield concrete, containing minute amount of impurity elements, was activated by neutron reaction during the operation of the reactor. A variety radionuclides was generated in the concrete, including $^3H$, $^{14}C$, $^{55}Fe$, $^{60}Co$ $^{63}Ni$, $^{134}Cs$, $^{152}Eu$ and $^{154}Eu$. In this paper, the comparison between the calculated results and previous measured results was carried out to estimate the inventory of the bioshield concrete of the KRR-2. The combined computer codes of MCNP5 and ORIGEN 2.1 for calculation of the distribution of neutron flux, cross-section and generation of radionuclides were used. The results were shown that 99.8% of the total radioactivity of $^3H$, $^{55}Fe$, $^{60}Co$ and $^{152}Eu$ in the bioshield concrete 12 years after shutdown. The effects on the variation of inventory were analysed depending on the operation periods and the cooling times in the bioshield concrete.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.233-238
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• 2008

Korea has a high volume of exhaust in environmental pollutants compared to her economic size, which results from the increase of the ratio in high energy consuming industries. There arises an issue that efficient energy saving is not achieved in the related projects of the construction, which is one of the high energy consuming industries. In addition, such projects of dismantling old and decrepit buildings are frequent in recent years. Given the situation, to obtain much better effects of energy saving, it is necessary to build basic databases and develop utilization plans on energy consumption volume, exhaust volume of pollutants, and environmental expenses that come from the dismantlement stages out of the life cycle of construction projects. Therefore, this study calculates the exhaust volume of environmental pollutants, converts it into environmental expenses by pollutants, and evaluates the environmental economics on the projects of dismantling buildings, utilizing LCI DB that is suggested by Ministry of Knowledge Economy and Ministry of Environment. For this purpose, related data research, the existing literature study, and on-the-spot field investigation were conducted. Based on the results of analysis on the collected data, the environmental economics of the target building was evaluated.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6D
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• pp.607-614
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• 2012

The importance of demolition industry is becoming lager because of reusing and recycling of construction waste in current trend to pursue for sustainable development. As considering situation of the domestic housing construction and existing house, a scale of demolition industry is expecting to be increased continually. Therefore, for sustainable development is needed forecasting and managing rightly demolition waste to be producted at demolition phase. But, The development of model for estimating demolition waste is not sufficient in the country, also, the development of computer system for managing it rightly has not yet been created. In this study developed the estimating waste units for estimating demolition waste of an apartment and a house. A regression model for quantifying demolition waste easily is developed to do simulation again after making the estimating waste units through analyzing draws. This model is developed as a computer system for increasing application and then verified the reliability through field application. this regression model can quantify a sort of 22 demolition waste easily based on the size of the floor area and a number of units. This system is expected to quantify demolition waste easily which is producted during redevelopment and remodeling of existing house.

• Explosives and Blasting
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• v.22 no.1
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• pp.33-43
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• 2004

In this study, a comparison was made between the resulting behaviors of scaled model test and particle flow analysis for blasting demolition of a reinforced concrete structure. For the test and analysis, a progressive failure of a five-story structure was considered. The dimension analysis was carried out to properly scale down the real structure into the laboratory size. The test model was made of the mixture of gypsum, sand and water along with soldering lead to analogy reinforcing steel bars. The ratio of mixing components was chosen to best represent the scaled down strength and deformation modulus. The columns and girders of the structure were precasted in the laboratory and assembled right before the blasting test. The numerical analysis of the blasting demolition was carried out using PFC2D (Particle Flow Analysis 2-Dimension by Itasca). The results of the blasting of concrete lahmen structure showed roughly identical demolition behavior between scaled model test and numerical test. For the blasting of the reinforced concrete structure, the results were more identical and closer to the real demolition behavior, since the demolition behavior was better represented in this case due to the increased tensile strength of the component.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.1
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• pp.21-34
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• 2015

Source term analysis should be carried out to prepare the decommissioning of the nuclear power plant. In the planning phase of decommissioning, the classification of decommissioning wastes and the cost evaluation are performed based on the results of source term analysis. In this study, the verification of MCNP/ORIGEN-2 model is carried out for preliminary source term calculation for Wolsung Unit 1. The inventories of actinide nuclides and fission products in fuel bundles with different burn-up were obtained by the depletion calculation of MCNPX code modelling the single channel. Two factors affecting the accuracy of source terms were investigated. First, the neutron spectrum effect on neutron induced activation calculation was reflected in one-group microscopic cross-sections of relevant radio-isotopes using the results of MCNP simulation, and the activation source terms calculated by ORIGEN-2 using the neutron spectrum corrected library were compared with the results of the original ORIGEN-2 library (CANDUNAU.LIB) in ORIGEN-2 code package. Second, operation history effect on activation calculation was also investigated. The source terms on both pressure tubes and calandria tubes replaced in 2010 and calandria tank were evaluated using MCNP/ORIGEN-2 with the neutron spectrum corrected library if the decommissioning wastes can be classified as a low level waste.

• Tunnel and Underground Space
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• v.14 no.1
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• pp.54-68
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• 2004

In this study, scaled model tests were performed on blasting demolition of reinforced concrete structures and the experimental results were analyzed in comparison with the results of numerical analysis. The tests were designed to induce a progressive collapse, and physical properties of the scaled model were determined using scale factors obtained ken dimension analysis. The scaled model structure was made of a mixture of plaster, sand and water at the ratio determined to yield the best scaled-down strength. Lead wire was used as a substitute for reinforcing bars. The scaled length was at the ratio of 1/10. Selecting the material and scaled factors was aimed at obtaining appropriately scaled-down strength. PFC2D (Particle Flow Code 2-Dimension) employing DEM (Distinct Element Method) was used for the numerical analysis. Blasting demolition of scaled 3-D plain concrete laymen structure was filmed and compared to results of numerical simulation. Despite the limits of 2-D simulation the resulting demolition behaviors were similar to each other. Based on the above experimental results in combination with bending test results of RC beam, numerical analysis was carried out to determine the blasting sequence and delay times. Scaled model test of RC structure resulted in remarkably similar collapse with the numerical results up to 900㎳ (mili-second).

• Explosives and Blasting
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• v.27 no.1
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• pp.62-78
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• 2009

Recently, construction techniques have been rapidly developed with reconstruction of old buildings, urban regeneration and efforts of restoring natural ecology, so demolition of deteriorated buildings has been rapidly increasing. Demolition work of building should be executed without damaging surrounding environments according to relevant regulations. There are various demolition methods and among them, explosives demolition is the most practical way for expenses and safety of work. As a part of Daejeon stream ecological restoration project, this thesis is a case of executing demolition of Chung-Ang Department Store which was built 35 years ago as covered structure on the upper part of Daejeon stream with explosives demolition. This structure is 8 stories high, total height of 41.6 m including basement floor, $1,650m^2$ for building area and $18,351m^2$ for total floor area. It is located in the center of Daejeon city where shopping centers and buildings are crowded and main facilities are Daejeon subway (18m), backside shopping center (20m), underground shopping center(15m), Mokchuk bridge, Eunjung bridge(0.25m) and fiber-optic cable(0.25m). In this project, implosion was selected for explosives demolition methods by considering this area being a busy urban area, and this project was executed after examining collapse movement of structure in advance using simulation program not to damage main facilities. Total 80kg of explosives and 1,000 detonators were being used. This project will be a good case of executing explosives demolition successfully by applying implosion on urban area in the country.