• 한국구조물진단유지관리공학회 논문집
• /
• 제11권1호
• /
• pp.171-180
• /
• 2007

처짐, 응력 및 휨강도 한계상태에 대한 PSSC(prestressed steel and concrete)거더의 신뢰도해석을 수행한다. PSSC 거더는 시공비용과 형하공간의 확보 면에서 지간 40m이상인 교량에 적용하는데 커다란 장점을 가지고 있는 형식이다. 이 논문에서는 다양한 지간, 단면 및 설계 응력수준을 가지는 PSSC 거더를 설계하여 중앙점 처짐, 응력 및 단면 휨모멘트 해석을 수행하고, 각각에 대한 한계상태를 가정한 후, Monte-Carlo 시뮬레이션과 Rackwitz-Fiessler 방법을 이용하여 신뢰도지수를 구한다. 결과를 분석하면 PSSC 거더에 대한 처짐한계상태는 응력한계상태보다 적절하게 큰 신뢰도지수 값을 보이며, 휨강도에 대한 신뢰도지수가 매우 큼을 알 수 있다.

• 전기학회논문지
• /
• 제66권3호
• /
• pp.500-506
• /
• 2017

In 2014, ISO 55000s has been enacted and the power plant asset management is becoming a hot issue for all over the world. The asset management system is being developed as a combination of CBM(Condition Based Maintenance) and RCM(Reliability Centered Maintenance). Therefore, the research on the calculation of the failure rate which is the most basic index of RCM is actively carried out. The failure rate calculation has been going on for a long time, and the most widely used probability distribution is the Weibull distribution. In the Weibull distribution, the failure rate function is determined in three types according to the value of the shape parameter. However, the Weibull distribution has a limitation that it is difficult to apply it when the trend of failure rate changes-such as bathtub curves. In this paper, the failure rate is calculated using the mixture Weibull distribution which can appropriately express the change of the shape of the failure rate. Based on these results, we propose the necessity and validity of applying mixture Weibull distribution.

• 한국구조물진단유지관리공학회 논문집
• /
• 제6권4호
• /
• pp.189-199
• /
• 2002

This study is intended to propose a systematic procedure for the development of the conditional assessment based on the safety of structures and the cost effective performance criteria for designing and upgrading of bridge structures. As a result, a set of cost function models for a life cycle cost analysis of bridge structures is proposed and thus the expected total life cycle costs (ETLCC) including initial (design, testing and construction) costs and direct/indirect damage costs considering repair and replacement costs, human losses and property damage costs, road user costs, and indirect regional economic losses costs. Also, the optimum safety indices are presented based on the expected total cost minimization function using only three parameters of the failure cost to the initial cost (${\tau}$), the extent of increased initial cost by improvement of safety (${\nu}$) and the order of an initial cost function (n). Through the enough numerical invetigations, we can positively conclude that the proposed optimum design procedure for bridge structures based on the ETLCC will lead to more rational, economical and safer design.

• 한국구조물진단유지관리공학회 논문집
• /
• 제7권4호
• /
• pp.217-224
• /
• 2003

본 연구에서는 구조 응답의 불확실성을 고려하여 신뢰성해석을 수행한 후 구조물의 최적설계를 수행하기 위한 프로그램 기법을 제안하고자 한다. 신뢰성해석을 위해 AFOSM법을 이용하였으며, 해석에 의한 파괴확률과 신뢰도 지수값을 제약조건으로 이용하여 최적설계를 수행하였다. 최적설계방법으로는 최적정기법으로 가장 강력한 SQP법을 사용하였다. 제약조건과 불확실량 고려 유 무에 따른 해석결과 본 연구에서 대상으로 한 트러스의 경우 불확실량을 고려한 경우 최소중량이 20.92%, 평면골조의 경우 평균 8.08% 증가하였다.

• 한국구조물진단유지관리공학회 논문집
• /
• 제13권5호통권57호
• /
• pp.142-148
• /
• 2009

이 논문에서는 3축 가력상태에 놓인 박스형 암거의 극한파괴실험을 실시하고 박스형 암거의 파괴거동 특성을 파악하고 하중증가에 따른 균열폭의 변화를 측정하였다. 현실적인 외압상태를 모사하기 위해 상부 및 좌,우측부에서 동시에 가력할 수 있는 3축 가력시스템을 이용하여 하중을 재하 하였다. 하중 증가에 따른 상부슬래브 및 좌,우측 벽체에서의 균열양상을 관찰하였으며 상부슬래브에서의 균열폭 증가량을 정량적으로 측정하였다. 이를 통해 균열폭 증가에 따른 구조손상도를 실험적으로 정량화시켜 박스형 암거의 구조내력저하지수를 실험적으로 추정하였다.

• 산업경영시스템학회지
• /
• 제46권4호
• /
• pp.321-330
• /
• 2023

The Korean military has sought to build an all-round military force against the national and international security environment and future asymmetric threats as well as the military threats it faces. However, while raising the need for timely electrification, there are few cases of quantitatively evaluating the loss when electrification is delayed, making it difficult for our military to provide a logical basis to support the importance of the electrification period. Therefore, through this study, we tried to analyze the index of loss cost that can support the need for timely electrification with logical and quantitative data and present it as a logical basis. To this end, the loss cost was calculated in terms of combat efficiency, equipment utilization rate, and maintenance requirements, which can be quantitatively calculated based on "combat readiness," a general impact on the military in case of delayed timely electrification.

• 국제학술발표논문집
• /
• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
• /
• pp.521-525
• /
• 2011

Although the Korean construction industry has risen rapidly, the quality of the buildings is not met with the industry standard compared to the potential of the technology development and the cost of maintenance has been increased. The user's request for quality have been increased, but in the current building construction, the contractors only follow the specifications of design, material and technology, and their main concern is whether they are in right track with the specification or not. Thus, the necessity of developing technology has been ignored and sufficient opportunities for the development have not been provided as well. In the developed countries, in contrast, the quality assurance and the payment regulation system has been utilized for the active response to the changes of users' request. As a result of this, the maintenance cost has been decreased and the development of construction technology has been improved. Therefore the pay adjustment system is needed to create the improvement of the quality of the buildings by the contractors' earnest building construction. In order to introduce the pay adjustment system suitable to the Korean construction industry, this study presented the logical method of adjusting the construction cost and making payment with the pay adjustment index that is created based on the result of the performance test, after making a set of the indicators of the building performance standard and applied them to the targeted building.

• Journal of Periodontal and Implant Science
• /
• 제29권3호
• /
• pp.715-724
• /
• 1999

The purpose of this study was to approve the possibility of clinical application of selftesting technique to confirm the cleanness status of the tooth surface after mechanical toothbrushing. Thirty-two periodontal patients who did not compromise any other systemic diseases were divided into two groups. Control group was instructed only the Bass method for toothbrushing, and then experimental group was demonstrated the Bass method and self-testing technique respectively for plaque control during this experiment. Selftesting technique is composed the comparison of roughness of the labial surface of maxillary central incisor and other toothsurface with touch sense using the tip of tongue. Plaque score and Gingival index were measured as clinical parameters at baseline and 1, 2 and 4 weeks after scaling and root planing. The results were as follows ; 1. Plaque scores and gingival index of 1, 2, and 4 weeks of two groups were statistically significant differences when compared with baseline value (p<0.05). 2. Plaque scores and gingival index of baseline and 1 week between two groups were not significant differences (p<0.05). 3. Plaque scores and gingival index of 2 and 4 weeks of test group were statistically significant difference when compared with control group (p<0.05). From the above results, self-testing technique which decides necessity of additional toothbrushing when tongue tip of subjects touch the maxillary molar buccal surfaces and mandibular molar lingual surfaces nd compares with maxillary anterior labial surfaces after toothbrushing appeared to effect the motivation of subjects. This study suggests that self-testing technique for cleanness after toothbrushing should be effect on the maintenance of oral hygiene when it is applied to clinical practice.

• Pediatric Infection and Vaccine
• /
• 제18권2호
• /
• pp.117-123
• /
• 2011

목 적: 홍역, 유행성이하선염 및 풍진 예방접종 시행후 연령 증가에 따른 항체양성율의 변화를 조사한다. 방 법: 병원에 내원한 7-20세의 환아를 대상으로 잔여 혈청을 이용하여 IgG 항체를 검사하였다. 결 과: 총 408례 중 홍역은 275례로 67.4%, 유행성이하선염은 112례로 27.5%, 풍진은 367례로 90.0%의 양성율을 보였다. 양성자의 IgG 수치는 각각 $2.77{\pm}1.18$ Index, $2.08{\pm}1.29$ Index 및 $60.46{\pm}63.47$ IU/mL 이었다. 결 론: 홍역 67.4%, 유행성이하선염 27.5% 및 풍진 90.0%의 IgG 항체 양성율을 보였다. 홍역, 유행성이하선염 및 풍진의 유행을 막기 위해서는 높은 접종율의 유지가 중요하며, 또한 보호자에 대한 접종기록 등의 관리가 중요할 것으로 생각된다.

• 한국콘텐츠학회논문지
• /
• 제9권6호
• /
• pp.196-206
• /
• 2009

병원의 수익성이란 병원이 회계년도 기간동안 환자 진료 및 기타 경영활동을 통해 달성한 경영성과를 말한다. 본 연구는 병원의 수익성 측정 지표로 병원을 운영하여 얻은 의료수익에서 의료비용을 뺀 순수한 의료이익인 의료수익의료이익율을 사용하였다. 이를 통해 수익성에 영향을 미치는 다양한 지표를 대상으로 병원 수익성 관련 요인을 도출하였다. 이 결과를 토대로 병원의 수익성 제고 방안을 강구할 수 있는 보다 유용한 기초자료를 산출하고자 하였다. 분석결과 공공병원이 민간병원보다 수익성이 낮았다. 각 지표의 수익성을 적자병원군과 흑자병원군으로 구분하여 분석한 결과 인건비 비율, 관리비 비율, 전문의 1인당 수술건수, 의료장비 회전율와 관련한 지표에서 유의한 차이를 보였다. 관련 지표가 수익성에 미치는 영향을 보면 모형에 따라 설명력은 25%-74.5%였다.