• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.6
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• pp.667-681
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• 2012

In general, risk management consists of a series of processes or steps including risk identification, risk analysis, risk evaluation, risk mitigation measures, and risk re-evaluation. In this paper, potential risk factors that occur in shield TBM tunnels were investigated based on many previous case studies and questionaries to tunnel experts. The risk factors were classified as geological, design or construction management features. Fault Tree was set up by dividing all feasible risks into four groups that associated with: cutter; machine confinement; mucking (driving) and segments. From the Fault Tree Analysis (FTA), 12 risk items were identified and the probability of failure of each chosen risk item was obtained.

• Journal of applied mathematics & informatics
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• v.27 no.3_4
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• pp.843-856
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• 2009

In possibility framework, we propose two risk measures named Fuzzy Value-at-Risk and Fuzzy Conditional Value-at-Risk, based on Credibility measure. Two portfolio optimization models for fuzzy portfolio selection problems are formulated. Then a chaos genetic algorithm based on fuzzy simulation is designed, and finally computational results show that the two risk measures can play a role in possibility space similar to Value-at-Risk and Conditional Value-at-Risk in probability space.

• Journal of the Korean housing association
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• v.12 no.4
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• pp.93-104
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• 2001

This study has been performed to analyze size and deficit problem of residential space in later life. In this study, 216 Koreans aged 50 to 79 were surveyed for their current residential space ad family related items such as age, marital status, living arrangement, birth order, and housing status. The results are drawn as follows: 1. The space size significantly fluctuates by marital status, number of generations living together, tenure, and structure type; For example, use of indoor area per person ranges from 7.01 pyoung for three-generation households to 19.53 for one-generation households. 2. s for space deficit, very old widowed females, 60's living in rented or multi-family housing units, and those living in three generations are high risk groups of the space deficit below 7 young per person. In this study, further researches are recommended as follows; Regarding the highest risk group of space deficit, life styles causing space-related conflicts should be studied, and accordingly proper welfare services for the causal life styles be offered. Housing maintenance & utility costs be investigated and guidelines should be proposed for any surplus groups among the 60's, so that their space surplus can be reduced by suitable adjustment process.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.6
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• pp.683-697
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• 2012

In this paper, a risk analysis methodology applicable to shield TBM tunnels was studied. Fault Tree Analysis (FTA) was utilized to identify all risk items and to calculate the probability of failure of each item and Analytic Hierarchy Process (AHP) was used to obtain the impact of each risk item. Finally, a risk level of each risk item can be assessed. Developed methodology is applied to a Seoul subway site in which EPB shield tunnel method was utilized and it was found that risk analysis results matched reasonably well with field data.

• Journal of the Korea Safety Management & Science
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• v.5 no.4
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• pp.13-20
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• 2003

The purpose of this study is to know the status of prevention on health obstacle in industries with confined space. Total 190 respondents, 95 safety or health managers and 95 confined space workers from 95 industries with confined space are surveyed by hygienists from April 2003, to July 2003. The contents of survey include health-work program in confined space, instrument of oxygen sampling, equipment of ventilation, safety and health education, watching manager, head count, awakening of risk, air condition and emergency training. The results are as follows: 1. It is found 38% of respondents established health-work program in confined space. The percentage of respondents with instrument of oxygen sampling and equipment of ventilation, operation of safety and health education, posting of watching man and operation of head count are 42%, 35%, 75%, 46% and 56%, respectively. 2. The percentage of awakening of risk, confirm of air condition and operation of emergency training are 36%, 25% and 15%, respectively.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.1
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• pp.63-74
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• 2007

Unexpected ground conditions have always been a major problem for the construction of tunnel. Therefore, it is necessary to evaluate the risk capacity before and/or during construction of new tunnel. This paper presents the simplified risk assessment system using modified stability number (N), namely Underground Risk Index (URI) system, to evaluate the tunnel risk possibility in the design stage. URI is a scoring system for risk possibility by rating the each appraisal elements. The modified stability number (N) which is one of risk factor in the Interaction Matrix parameters such as RQD, UCS, weathering, overburden, stability number, ground water-table, RMR, permeability and so on, is used in the system. In addition, the case study is performed in order to verify the applicability of URI-system in practice.

• Nuclear Engineering and Technology
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• v.46 no.1
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• pp.27-38
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• 2014

The Fukushima Dai-Ichi accident in 2011 has affected various aspects of the nuclear society worldwide. The accident revealed some problems in the conventional approaches used to ensure the safety of nuclear installations. To prevent such disastrous accidents in the future, we have to learn from them and improve the conventional approaches in a more systematic manner. In this paper, we will cover three issues. The first is to identify the key issues that affected the progress of the Fukushima Dai-Ichi accident greatly. We examine the accident from a defense-in-depth point of view to identify such issues. The second is to develop a more systematic approach to enhance the safety of nuclear installations. We reexamine nuclear safety from a risk point of view. We use the concepts of residual and unknown risks in classifying the risk space. All possible accident scenarios types are reviewed to clarify the characteristics of the identified issues. An approach is proposed to improve our conventional approaches used to ensure nuclear safety including the design of safety features and the safety assessments from a risk point of view. Finally, we address some issues to be improved in the conventional risk assessment and management framework and/or practices to enhance nuclear safety.

• Journal of Korean Society of societal Security
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• v.3 no.1
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• pp.61-66
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• 2010

Recently a construction industry introduces information technology that brings about many advantages in the early planning phase, design phase and construction phase. Nevertheless a BIM has a many benefits, it has limits which are not only usually using 3D modeling but also limit of making full use of practical affairs because of a lack of connecting varietals of progress of work. To solve these uppermost limits, this research is presenting unified systems to use in risk management which are efficient management of space and non-space information, space analysis.

• Journal of the Korea Institute of Building Construction
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• v.7 no.3
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• pp.91-98
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• 2007

Recently a construction industry introduces information that brings about many advantages in the early planning phase, design phase and construction phase. Especially it replaces 2D, 3D systems(usually using explanation of drawing information) ai 4D CAD(offering a sort of 4D-having relation of construction schedule and 3D drawing information). Nevertheless a 4D has these benefits, it has limits which are not only usually using 3D modeling but also limit of making full use of practical affairs because of a lack of connecting varietals of progress of work. To solve these uppermost limits, this research is presenting unified systems to use in risk management which are efficient management of space and non-space information, space analysis, making full use of data base, introducing GIS system of easy interaction.

• Magazine of korean Tunnelling and Underground Space Association
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• v.22 no.3
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• pp.37-53
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• 2020