• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.932-934
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• 1998

Electric power distribution feeders are susceptible to faults caused by a variety of situations such as adverse weather conditions, tree contacts, equipment failure, accidents, etc. Distribution circuit faults result in a number of problems related to the reliability of service and customer power quality. In the past, the permanent interruption of customer service resulting from a blown fuse or a recloser lockout was the only factor which was used to determine service reliability. So we developed KODAS(Korea Distribution Automation System) with successful and had fieid-testing of Distribution Automation System in last three years at Kang-dong Branch Office. In performing the project, KEPRI has gained valuable experience, through dealing with many difficult problem. This paper is depicted about the circuit breaker coordination problems in the Underground for the Distribution Automation Feeder.

• Journal of the Korea Safety Management & Science
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• v.17 no.2
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• pp.13-25
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• 2015

In recent years, the surroundings of Fire have rapidly changed and citizens need for Fire have been demanding very high. Under these situations, in order for satisfaction to all these demands, Seoul Emergency Operations Center have made improvements as the core fire operational center in Korea. However, There have been so many problems happening in the middle of receiving calls from malice citizens of Seoul. The purpose of this study is to scrutinize current operations focused on fire fighters in Seoul Emergency Operations Center and to cope with how to overcome these problem by using AMOS 21 & SPSS Statistics 21. The result of this study presents that how we can find to be Seoul Emergency Operations Center running well. And This study is applied to seoul fire policies or helped to setting them up.

• Journal of Applied Reliability
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• v.1 no.1
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• pp.1-8
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• 2001

Redundancy allocation problems have been considered at single-level systems and it may be the best policy in some specific situations, but not in general. With regards to reliability, it is most effective to allocate the lowest objects, because parallel-series systems are more reliable than series-parallel systems. However, the smaller and lower in the system an object is, the more time and accuracy are needed for duplicating it, and so, the cost can be decreased by using modular redundancy Therefore, providing redundancy at high levels like as modules or subsystems, can be more economical than providing redundancy at low levels or duplicating components. In this paper, the problem in which redundancy is allocated at all level in a series system is addressed, a mixed integer nonlinear programming model is presented and a genetic algorithm is proposed. An example illustrates the procedure.

• Journal of Applied Reliability
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• v.16 no.1
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• pp.71-77
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• 2016

Purpose: Root cause analysis (RCA) refers to any systematic process that identifies the causes that contribute to a focus event. The immediate cause of a focus event is often a symptom of underlying causes and may not truly identify the root causes that should be identified and addressed. Currently many RCA tools are available. Different investigators use different RCA tools on different issues. No standardized or commonly agreed way to analyse root causes exists. The purpose of this study is to propose the methodology of RCA process commonly useable for various issues. Methods: The methodology of RCA process is produced based on the hybrid RCA tools. The effectiveness assessment matrix of actions through the root cause candidates is presented. Results: No single RCA technique proposed has so far covered all necessary aspects. A hybrid approach which combines the best features of various techniques is proposed. The effectiveness assessment matrix helps us to identify the root cause to correct or eliminate system vulnerabilities effectively. Conclusion: This hybrid approach and effectiveness assessment matrix can provide guidance of RCA process across many industries and situations.

• Journal of Industrial Technology
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• v.18
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• pp.139-148
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• 1998

Traditionally, the problems of manufacturing technology and manufacturing management have been treated independently. In this research, we endeavor to integrate the process planning and scheduling activities as an attempt to integrate the two realms. To draw up a plan of process planning and scheduling in real manufacturing environment is not an easy task because available time to plan could be limited and the shop status could change frequently. So we propose an architecture of integrated process planing and scheduling problem within the allowed time even if sheep situations change rather frequently. We argue that we can obtain a better and practical scheduling solution by dynamically changing the processing machines and operations as the shop condition changes. The proposed system takes the initial information for alternative machines and operations represented by an AND/OR graph as its input. Other informational inputs to the system are part order and shop statues. The system then generates new process plan and schedules during permitted time. Experimental results show that the proposed scheme provides a viable solution for real world scheduling problems.

• Korean Journal of Child Studies
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• v.26 no.4
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• pp.247-247
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• 2005

The attachment representation of 40 36- to 52-month-old upper-middle class children was analyzed in relation to their attachment security and mother-child interaction behaviors. Instruments were the Attachment Story Completion Task(Bretherton, Ridgeway, & Cassidy, 1990), the Attachment Q-set, and the Vocabulary test of the K-WIPPSI. Mother-child interaction behaviors were observed at home during semi-structured problem-solving situations. The Attachment Story Completion Task classified Korean preshoolers from these upper-middle class families as securely attached to their mothers. Girls' representation of their attachment relationship was more secure than boys. Preschoolers' attachment representation was significantly related to vocabulary ability. Attachment security correlated positively with preschool children's attachment representation. Mother-child interaction behaviors related significantly to preschool children's attachment representation.

• Korean Journal of Child Studies
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• v.33 no.1
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• pp.133-145
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• 2012

The present study systematically analyzed the relationships between children's emotional and behavioral problems, attachment, fears and coping behaviors. The subjects of this study were 63 school-aged children residing in Seoul, Gwangiu and South Jeolla province. The findings indicated that emotional and behavioral problems were negatively correlated to children's attachments to their fathers and peers. The children's attachment to peers had a significant correlation as well as behavioral problems and coping strategies used by children in stressful situations. Emotional problems were explained by fears of realistic objects, the seeking out of social support, mother and father attachment, and fears of imaginary objects. In addition, behavioral problems were explained by aggressive coping behaviors and child-father attachment.

• Structural Engineering and Mechanics
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• v.33 no.4
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• pp.485-502
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• 2009

A new 8-node serendipity quadrilateral plate bending element (MQP8) based on the Mindlin-Reissner theory for the analysis of thin and moderately thick plate bending problems using Integrated Force Method is presented in this paper. The performance of this new element (MQP8) is studied for accuracy and convergence by analyzing many standard benchmark plate bending problems. This new element MQP8 performs excellent in both thin and moderately thick plate bending situations. And also this element is free from spurious/zero energy modes and free from shear locking problem.

• Korean Journal of Bronchoesophagology
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• v.3 no.2
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• pp.261-269
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• 1997

When performing an endotracheal intubation or tracheotomy to an unconscious patient in emergent situations, one should consider the possibility of later complication of laryngo-tracheal stenosis which can result in difficulties in decannulation. Laryngo-tracheal stenosis is a bothersome problem developing as a complication of treatment by tracheotomy with a cuffed tube and long-term endotracheal intubation with assisted ventilation. One hundred twenty-three cases of laryngo-tracheal stenosis patients during the four yew period from May 1992 to April 1996 were restrospectively reviewed according to several parameters such as the duration of intubation, site of stenosis, treatment modality and, site of tracheostoma. The present report is an analysis of these materials to search for the possible etiologic factors and its proper preventive methods. It was desirable that the endotracheal intubation should be limited within 20 days at most. Tracheotomy performed by non-otolaryngologists has a tendency to be on a higher level of trachea. Technical precautions should be taken into consideration when doing a tracheotomy. The success rate of decannulation of tracheal T-tube was 78.8% and it required average 11 months.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.3
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• pp.87-94
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• 2003

When faults occur in a distribution network, blackout loads must be restored as fast as possible to minimize interruption of electric service. This paper presents an expert system to restore distribution networks. The system is designed to minimize switching operations in a heuristic sense by using heuristic rules. The restoration process is converted to the feasible path finding problem in the state space of expert system by application of general topological knowledge base. Multiple load transfer algorithm is proposed to deal with complex situations.