• Journal of the Korean Data and Information Science Society
• /
• 제15권1호
• /
• pp.21-29
• /
• 2004

In this paper, we define an availability of repairable network system, when the states of links are modeled by alternating renewal processes. The actual availabilities of some well-known network systems are obtained. The expected numbers of failures and repairs of the network systems are also calculated.

• 대한산업공학회지
• /
• 제13권2호
• /
• pp.59-63
• /
• 1987

An age replacement policy is considered for a system under a stepdown warranty. It is assumed that only minimal repairs are performed for failures occurred before age T.A unique optimal value of T which minimiges the expected cost rate is obtained. The cases of the free replacement warranty, prorata warranty and hybrid warranty are also considered and some numerical examples are given.

• 산업경영시스템학회지
• /
• 제14권24호
• /
• pp.43-52
• /
• 1991

The short-term production planning of an automated manufacturing system is to determine the production rate of each part type or family of part types. The purpose of this paper is to develop an optimal algorithm for solving the short-term production planning problem while machine failures, repairs. and changes in demand requirements are anticipated. The problem is formulated by LP and it shows that the production surplus is approached or stays at the hedging point. In addition, the long-term average frequencies of set-us with relation to a multilevel hierarchical production planing scheme are considered An example to show the effectiveness of the algorithm is presented.

• 품질경영학회지
• /
• 제22권3호
• /
• pp.54-65
• /
• 1994

A hybrid warranty policy for a repairable item is considered. Assuming that minimal repairs ar e performed for failures during warranty period, present worth of warranty cost is derived from a supplier's viewpoint. An optimal preventive periodic replacement policy for the case is also derived from a user's viewpoint Numerical examples are presented in order to explain the results.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 추계학술대회 논문집
• /
• pp.561-566
• /
• 2008

The EMU of maintenance technique or system is changing on a large scale. To subway operation beginning the breakdown was born and every that time after the fact repaired. But, recently before the breakdown of the subway occurs, repairs in advance with the preventive maintenance concept which was exchanged. However, the preventive maintenance is to readjust, cleaning, tighten and the oil the repetition by the worker simple experience. This study on introduces the EMU of maintenance method which applies a automatic inspection equipment from the study contributing which develops the preventive maintenance system.

• 건축역사연구
• /
• 제16권5호
• /
• pp.21-40
• /
• 2007

Choryang-weagwan which was the largest international trading place between Joseon Dynasty and Tokugawa Shogunate had been maintained from 1678 through 1872 in Busan. Particularly, they had 21 times repairing constructions for 200 years since its establishment. It is noticeable that Joseon Dynasty permitted Tokukawa Shogunate to construct main pavilions and guesthouses as his style due to the good-neighbor policy between two countries, and Tokukawa Shogunate struggled to achieve his own culture in that place under the supervision of Joseon Dynasty. For satisfying his needs, the architectural craftsmen of Tokukawa Shogunate were mobilized by the chief of construction company which was called kumi-gasira in the most of cases. When they came to Busan for the construction, they brought their own architectural tools. On the one hand, the carpenters and workers of Joseon Dynasty were organized by the traditional construction superintendents which were called Gamdong-gwan and they had to carry out their responsibilities with Japanese technicians at the same workplace. Judging from this fact, the construction site of Weagwan was the good place for exchanging the architectural technology between two countries. This study especially focuses on Tokukawa Shogunate craftsmen who made the repairs of Dongwan-samdaechung in 1727 such as carpenters(Dai-ku), sawyers(ko-biki), and surveyors(Tsue-tsuki) and their tools such as Hatsuri(=Masakari) and Yo-ki(=Oh-no). The constructions in this period, there were not only the repairs of 3 major pavilions including the trading center, but also one of the most active repairing constructions comparing with other period, therefor these were important constructions to shows us repairing construction of Choryang-weagwan of those days.

• 한국건설순환자원학회논문집
• /
• 제5권3호
• /
• pp.239-246
• /
• 2017

콘크리트 구조물은 목표내구수명동안 초기의 시공에 따른 내구수명과 보수를 통한 내구수명 확보를 통하여 성능을 유지한다. 결정론적인 방법에서는 내구한계에 이르면 보수횟수에 따라서 경비 및 탄소량이 계단식으로 증가하지만, 확률론적인 방법을 이용할 경우, 보수 경비와 탄소량을 연속적으로 도출할 수 있으며, $CO_2$의 흡착을 고려할 경우, 더욱 탄소량을 감축시킬 수 있다. 본 연구에서는 탄산화에 노출된 지하구조물에 대하여 결정론 및 확률론적인 방법을 배경으로 보수시기와 사용기간에 따른 흡착/발생 $CO_2$량을 평가하였다. 탄산화 깊이에 따른 $CO_2$흡착을 고려한 해석은 초기시공 및 보수재의 내구수명의 증가에 따라 탄소저감에 매우 효과적임을 나타내었다. 또한 초기 시공재료 및 보수재의 내구수명 변동성을 정의할 수 있다면, 확률론적 기법에서는 보수횟수를 감소시킬 수 있으므로 경비 및 $CO_2$저감에 효과적인 기법이 될 수 있다.

• 한국전산구조공학회논문집
• /
• 제23권2호
• /
• pp.191-198
• /
• 2010

이 연구에서는 접착패치보강의 서로 다른 형태 즉, 패치와 접착제의 재료, 크기, 두께 뿐만 아니라 일면보강 또는 양면보강에 따른 일변균열판의 응력감소에 대한 연구가 수행되었다. 수치해석 도구로는 p-수렴 부분층별 모델이 사용되었다. 이 모델의 면내 변위는 구간별 연속인 선형변화로 가정하였고, 두께방향으로의 면외 변위는 일정한 상수로 가정하여 적용하였다. 변위장의 정의는 적분형 르장드르 다항식을 적용하였고, 수치적분은 별도의 외삽법 없이 각 층별의 절점에서 발생하는 적분값을 바로 얻을 수 있는 가우스-로바토 적분법을 사용 하였다. 또, 에너지 방출률법을 사용하여 응력확대계수를 산출하였다. 수치예제를 통해 제안된 모델의 정확도는 물론이고 접착패치 보강형태에 따라 변화되는 무차원 응력확대계수와 처짐의 항으로 응력감소 효과를 분석하였다.

• Advances in pediatric surgery
• /
• 제1권1호
• /
• pp.8-17
• /
• 1995

The clinical experience of 2,340 inguinal hernia repaired by one pediatric surgeon on 2,079 children at Hanyang University Hospital from September 1979 to December 1993 was analyzed. Of 2,046 patients who had primary hernia repairs at Hanyang University Hospital, 1,636 were male and 410 female, and 55.5% of hernias occurred on the right side, 36.0% on the left, and 8.6% were bilateral. The patients presented hernia under the age of 12 months were 45.3% and those performed herniotomy under the age of 12 months were 25.5%. Birth weight was less than 2.5kg in 111 patients(8.7%) of 1,279 data available patients. Ninety(6.6%) of 1,354 data available patients were premature(<37wks gestation). The proportions of bilateral inguinal hernia and the onset age under 12 months of life in low birth weight babies and premature babies were higher than in full-term babies. Incarcerated inguinal hernia occurred in 327 patients(16.0%) of whom 8 patients were strangulated hernias. The occurrence of incarceration inversely related with age of patients. The subsequent contralateral inguinal hernia following unilateral hernia repairs occurred in 80 patients(4.3%) among which 72 were male and 8 were female. The incidence of contralateral inguinal hernia was more frequent in boys(4.8%) than girls (2.2%) and in cases after left herniotomy(6.4%) than after right herniotomy(2.9%). Sixty percent of contralateral inguinal hernia developed within 1 year after primary hernia repair. The recurrence of inguinal hernia occurred in 6 patients(0.27%) treated at our hospital primarily. There were one or more associated congenital anomalies in 83 patients of which congenital heart diseases were the most common. Sliding hernia occurred in 25 patients consisted of 5 boys and 20 girls. Family history was noted in 35 patients and there were 28 sets of monozygotic and 3 sets of dizygotic twins.

• Composites Research
• /
• 제17권4호
• /
• pp.68-73
• /
• 2004

본 논문에서는 한 쪽 면만 복합재 패치로 보강한 알루미늄 균열평판의 피로균열 진전거동을 해석적인 방법으로 고찰하였다. 한쪽 면 보강 시, 균열선단은 비대칭성과 면 외 굽힘의 효과로 인하여 초기의 직선형태에서 경사곡선형태로 진전한다는 사실을 이전의 연구견과에서 확인할 수 있다. 따라서 정확한 피로거동을 고찰하기 위하여는 이와 같은 균열선단의 변화과정을 예측하고, 이론 해석에 반영하는 것이 필수적이라 하겠다. 본 연구에서는 균열선단 전개형상을 고려한 한쪽 면 보강시의 피로해석을 수행하기 위하여 선형탄성 파괴역학개념을 적용한 3차원 순차적 유한요소 해석기법을 적용하였는데, 이를 통하여 진전하는 균열선단 형상을 단계적, 반복적으로 추적하고 해석모델에 반영하였다. 이와 같은 해석기법을 적용함으로써 패치보강 평판의 피로수명은 물론 균열선단 진전과정도 정확히 예측할 수 있었다. 해석으로 얻어진 균열선단 진전거동 및 피로수명은 상응하는 실험결과와 잘 일치함을 확인하였다.