• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.3
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• pp.283-291
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• 2015

In this paper, the two-dimensional(2D) and three-dimensional(3D) analyses have been performed in order to evaluate the structural integrities and compare 2D and 3D results for nozzles attached to cylindrical shells. Three nozzles, which are currently used in the nuclear power plant, are chosen to evaluate the structural integrities, and each nozzle is subjected to internal pressure, temperature variation and external loads. It is found that the 2D analysis for internal pressure should be performed with a factor of more than 1.5 or a stress concentration factor; 2D and 3D analysis results for temperature variation are almost similar to each other regardless of cladding; and the analysis results for external loads by WRC Bulletin 297 are more conservative than the 3D analysis results.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.3
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• pp.245-252
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• 2016

The development of Top-Mounted In-Core Instrumentation(TM-ICI) is an ongoing project to reduce the risk due to severe accidents by inserting the instrumentation into a reactor closure head instead of a reactor bottom head. As part of this project, environmental fatigue analyses for TM-ICI nozzle have been performed using two methods of NUREG/CR-6909 and Code Case N-761. TM-ICI nozzle is subjected to transient loads for level A, level B and test conditions that should be evaluated for a fatigue analysis. It is found that a cumulative usage factor considering reactor coolant environment for TM-ICI nozzle is evaluated as less than 1, which is ASME Code allowable criteria of a fatigue analysis.

• Corrosion Science and Technology
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• v.16 no.3
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• pp.115-127
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• 2017

Coal tar-coated pipes buried in a domestic nuclear power plant have operated under the cathodic protection. This work conducted the simulation of the coating performance of these pipes using a FEM method. The pipes, being ductile cast iron have been suffered under considerably high cathodic protection condition beyond the appropriate condition. However, cathodic potential measured at the site revealed non-protected status. Converting from 3D CAD data of the power plant to appropriate type for a FEM simulation was conducted and cathodic potential under the applied voltage and current was calculated using primary and secondary current distribution and physical conditions. FEM simulation for coal tar-coated pipe without defects revealed over-protection condition if the pipes were well-coated. However, the simulation for coal tar-coated pipes with many defects predict that the coated pipes may be severely degraded. Therefore, for high risk pipes, direct examination and repair or renewal of pipes are strongly recommended.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.3
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• pp.191-198
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• 2014

In this paper, structural integrity evaluation of reactor pressure vessel bottom head without penetration nozzles in core melting accident has been performed. Considering the analysis results of thermal load, weight of molten core debris and internal pressure, thermal load is the most significant factor in reactor vessel bottom head. The failure probability was evaluated according to the established failure criteria and the evaluation showed that the equivalent plastic strain results are lower than critical strain failure criteria. Thermal-structural coupled analyses show that the existence of elastic zone with a lower stress than yield strength is in the middle of bottom head thickness. As a result of analysis, the elastic zone became narrow and moved to the internal wall as the internal pressure increases, and it is evaluated that the structural integrity of reactor vessel is maintained under core melting accident.

• Journal of the Korea Society of Computer and Information
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• v.24 no.2
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• pp.127-137
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• 2019

In this study, we have developed a calculation system for BIM-based quantities, 4D process, and 5D construction costs, by integrating object shape attributes and the standard classification system which consist of Cost Breakdown System(CBS), Object Breakdown System(OBS) and Work Breakdown System(WBS) in order to use for the 4 dimensional process control of roads and rivers. First, a new BIM library database connected with the BIM library shape objects was built according to the CBS/OBS/WBS standard classification system of the civil engineering field, and a integrated database system of BIM-based quantities, process(4D), and construction costs(5D) for roads and rivers was constructed. Nextly, the process classification system and the cost classification system were automatically disassembled to the BIM objects consisting of the Revit-family style elements. Finally, we added functions for automatically generating four dimensional activities and generating a automatic cost statement according to the combination of WBS and CBS classification system The ultimate goal of this study was to extend the integrated quantities, process(4D), and construction costs(5D) system for new roads and rivers, enabling the integrated use of process(4D) and construction costs(5D) in the design and construction stage, based on the tasks described above.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.01a
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• pp.47-48
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• 2017

본 논문에서는 Microsoft Azure 플랫폼의 Azure PowerShell, Azure CLI(Command Line Interface), REST API를 활용하여 클라우드 기반 서비스 포털과 관리 포털을 개발함으로서 중소건설사에서 건설현장의 공사원가 관리 및 일일 관리를 위한 모듈과 서비스 제공을 위해 필요한 서비스 포털 및 관리 포털과 제품 관리 모듈 등 클라우드 서비스 구축 수행하였다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.149-153
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• 2009

Today, the form of competition among companies quickly changes in new paradigm. In the past company activity was performed independently, but now dependently. With global age, that change is essential, the introduction of a system that integrates a series of courses is needed for the success of members. Nevertheless, those change are very slow in construction industry, that causes a lot of loss in project process. Construction industry produce structures with collaboration of other industries. There are difficulties that only one company make it, alone. In this trend, cooperation is essential. but the process of original brings a lot of loss From this perspective, this study will prove dependencies of construction industry. Draw out each factor from industrial cooperation, those analyze correlation with system dynamics. In conclusion, this study performs a basic research about 'Integrated Management System' of construction project.

• Korean Journal of Construction Engineering and Management
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• v.14 no.3
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• pp.3-11
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• 2013

The changes in construction business have impact on overall operation of construction companies. Poor business of construction companies following a s low industrial cycle could have broader implications and influences on the industry. Since a construction project involves various stakeholders including public organizations, financial institutions and households, a downturn in construction industry might lead to significant economic loss. In this regard, it is meaningful to examine the relationship between changes in construction business cycles and insolvency of construction companies. This study conducts an empirical analysis of the relationship between construction business cycles and how much they affect operation of construction companies. To this end, KMV model was used to estimate probability of bankruptcy, which represents business condition of a construction company. To examine construction business cycles, investment amount for different construction types-residential, non-residential, and construction work-was used as a variable. Based on the investment amount, VECM was applied and the analysis results suggested that construction companies should put priority on diversifying project portfolio. In addition, it was shown that once a construction company becomes unstable in business operation, it is hard to recover even when the market condition turns for the better. This suggests that, to improve business operation of a construction company, internal capacity-building is as important as the market condition and other external circumstances.

• Journal of the Korean Society of Safety
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• v.19 no.1
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• pp.108-116
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• 2004

After the IMF financial crisis, a lot of risks in construction industry have been increased gradually with the expansion of construction industry widely, higher stories of building, and the expansion of the underground space and excavation work. These risks are bringing out construction accidents such as the death, the injury of worker and so on, not so much as it would be effected the corporation's image. In spite of these situations, many construction industries still maintain the wrong methods and not try to decrease construction accidents. Recently, we should focus on the fact that management system of the larger construction also is being good, on the other hand, the condition of the work in the case of smaller construction industries is very poor, construction company have a particular safety management system but it has a difference according to the construction magnitude, construction companies have a particular safety management system but it has a difference depending on the construction according to the construction magnitude. Therefore, this study will suggest the developed way of construction safety management by the comparison and analysis from the difference between the higher and the smaller construction industries.

• Journal of the Korea Institute of Building Construction
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• v.8 no.2
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• pp.131-136
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• 2008

Safety management is the most important factor in the construction industry. If the construction company don't control the risk, it causes the accident which give the company fatal loss. According to the Korea industrial safety analysis reports, the 25.72% of the disasters are from the construction industry, and the 13.6% construction disasters are caused by not properly using the safety gears. Therefore, this study is to investigate the Wearing Safety Gear by Occupational Classification and the Satisfaction in the Construction Field. The results are ; Carpenters are dissatisfied with the safety shoes and belt, re-bar workers are dissatisfied with the safety helmet and shoes, Concrete workers are dissatisfied with the safety helmet and goggles.