• International Journal of Reliability and Applications
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• 제12권1호
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• pp.41-48
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• 2011

This paper considers the maintenance model suggested by Jung and Park (2010) to adopt the Bayesian approach and obtain an optimal replacement policy following the expiration of NFRRW. As the criteria to determine the optimal maintenance period, we use the expected cost during the life cycle of the system. When the failure times are assumed to follow a Weibull distribution with unknown parameters, we propose an optimal maintenance policy based on the Bayesian approach. Also, we describe the revision of uncertainty about parameters in the light of data observed. Some numerical examples are presented for illustrative purpose.

• 대한산업공학회지
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• 제11권2호
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• pp.1-9
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• 1985

In this study, two stage transfer line with limited repair capability is modeled to formulate optimal dynamic repair priority policy. The method of Markov Chains is used to analyze the analytical model of this line. An efficient algorithm is developed, utilizing the block tridiagonal structure of the transition probability matrix, to obtain the steady state probabilities and system performance measures, such as the steady state production rate of the line and the average in-process inventory in the interstage buffer.

• Clinics in Shoulder and Elbow
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• 제20권4호
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• pp.183-188
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• 2017

Background: To evaluate the clinical outcomes and associated repair integrity in patients treated with arthroscopic repair for a transtendinous rotator cuff tear followed by resection of the remnant rotator cuff tendon. Methods: Between July 2007 and July 2011, we retrospectively reviewed patients who were treated for transtendinous full-thickness tears in the tendinous portion of the rotator cuff by arthroscopic repair. Clinical outcomes were evaluated using the American Shoulder and Elbow Surgeons (ASES) score, the Shoulder Rating Scale of the University of California at Los Angeles (UCLA), the Constant-Murley score, a visual analogue scale (VAS) pain score, and range of motion (ROM). The repair integrity was determined by magnetic resonance imaging or ultrasonography. Results: There were 19 shoulders with transtendinous full-thickness tears in the tendinous portion of the rotator cuff. The ASES, UCLA, Constant-Murley, and VAS pain scores showed significant improvements in function and symptoms (all p<0.001). The active ROM for forward flexion and abduction was also significantly improved (p=0.002 and p<0.001, respectively). The postoperative radiological examination showed cuff integrity without a re-tear in 68.4% of patients. However, the UCLA, ASES, and Constant-Murley scores were not significantly different between healed and re-torn group (p=0.530, p=0.885, and p=0.262, respectively). Conclusions: Although repair of transtendinous rotator cuff tears followed by resection of the remnant rotator cuff tendon in the footprint has a relatively high re-tear rate, no significant difference was observed in the short-term clinical results between the re-tear and healed groups.

• Journal of the Korean Data and Information Science Society
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• 제16권2호
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• pp.263-270
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• 2005

The reliability guarantee insurance policy for parts and materials was introduced to the market in 2003. This policy indemnifies manufactures for the repair/failure costs, recall expenses. In this paper, owing to the nature of the policy, we propose a new rate-making system considering the type of product and industry, quality control circumstances, record of guarantee performance, and exposures.

• Journal of Chest Surgery
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• 제30권4호
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• pp.373-377
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• 1997

소아에서의 선천성 승모판 폐쇄부전은 다른 기형의 동반과 함께 일찍 심부전을 일으키게 되나 기계 판막과 조직 판막 모두 소아에서는 한병증과 재수술을 요하는 바 자신의 조직을 최대한 이용하여 교정하는 것이 바람직하다. 1991년 1월부터 1995년 5월까지 15세이하의 소아에서 선천성승모판폐쇄부전증으로 32예에서 교정수술을 시행하였다. 나이는 3개월에서 9년 7개월(평균 24.0 $\pm$26.1) 이었으며 남아가 16예, 여아가 16예 였다. 26예(81 %)에서 심장기형을 동반하였으며 이중 심실중격결손증이 18예를 차지하고 있었다. 수술시 승모판막의 병리적 소견을 보면 판막윤의 확장만을 보인 경우가 7예, 판막침의 탈출증이 18예, 판막에 열이 있는 경우가 5예 그리고 판막침의 운동장애를 보인 경우가 2예 있었다. 판막의 교정은 판막윤 성형술만을 시행한 경우가 14예, redundant leaflet을 교정한 경우가 6예, 판막열을 폐쇄한 경우가 5예, 판막삭의 축소를 시행한 경우가 4예, 판막의 부분절제가 2예, 유두상근의 분리를 1예에서 시행하였다. 수술사망은 없었으며 만기사망은 심부전과 패혈증으로 2예에서 발생되었다. 추적관찰시 8예 에서 교정된 판막의 부전이 濚森퓸\ulcorner이중 2예에서 재수술을 시행하여 판막을 인공판막으로 치환하였다. 모든 환아의 46개월의 생존율은 92.5%를 보였으며 재수술회피율은 12개월, 46개월시 95%와 92.5% 를 보였고 판막교정의 실패율은 12개월,46개월시 68.7%와 61 8%를 보였다. 그러므로 소아에서 승모판의 교정수술은 비록 판막교정의 실패율은 높지만 낮은 사망과 낮은 재의 위험성을 보이기 때문에 소아에서 승모판폐쇄부전증은 가능곤판막의 재건으로 치료해야 할것으로 생각된다.

• 한국임상수의학회지
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• 제29권5호
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• pp.416-421
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• 2012

10살령의 4 kg 암컷 치와와가 심한 울혈성심부전의 수술적 치료를 위해서 내원하였다. 여러 가지 진단을 통해 이 환자는 심한 이첨판 폐쇄부전과 중등도의 삼천판 폐쇄부전이 확인되었다. 약물에 대한 치료적인 반응이 여의치 않아, 수술적으로 이첨판을 교정하는 치료방법으로 지시되었다. 체외순환을 이용한 심폐순환기하에서 이첨판교정술이 실시되었다. 하지만 이 환자는 교정 후에 마취에서 회복되지 못하고 사망하였다. 심장수술에 있어 실패를 유발하는 여러 가지 원인들에는 심폐순환기 운용, 저체온증, 장기부전, 출혈, 저혈압, 전해질과 산-염기 불균형, 그리고 감염 등이 있다. 비록 이 환자는 사망하였지만, 그 원인을 밝혀 내는 일은 수의학 분야에서 중요한 일이다. 이 증례의 사망원인을 고찰해 본 결과, 심한 저체온증에 의한 가스환기와 산소공급의 이상 그리고 심장수술과 관련한 저심박출량 증후군으로 인한 낮은 심박동수를 동반한 저혈압으로 사망한 것으로 생각되었다. 이 증례의 원인 규명을 위한 고찰은 이첨판성형술의 성공을 위해서는 좀더 세심한 주의가 요구됨을 알 수 있게 해주었고, 나아가 앞으로의 수술에서 성공률을 높일 수 있는 중요한 계기가 될 것이다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 추계 학술논문 발표대회
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• pp.63-66
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• 2008

Not only mechanical properties, bonding properties, electro chemical properties, etc. but also fire safety is required in patch repair materials such as polymer modified cement mortar (PCM) which are used to deteriorated reinforced concrete structure. Unfortunately, it is very difficult to choice the appropriate repair materials because there are not enough information about fire safety properties of PCM. In this study, The combustion characters of PCM were evaluated through the heat release rate test and non-combustibility test. The pyrogenicity test uses the cone calorimeter based on the oxygen consumption method. The non-combustibility test is from the temperature change inside the furnace during the test. The effect of the types of polymer and polymer content were evaluated from the series of test. The results are like followings. 1) The higher the W/C of PCM, the lower the gross calorific value and heat generation rate in the heat release rate test. The amount of heat generation of PCM is like the order of VVA, EVA, and SBR in this study. 2) Some materials such as E45-100, E50-100, E60-100, S50-50, and S50-100 were estimated as not appropriate building materials in the non combustibility test.

• Journal of Biosystems Engineering
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• 제6권2호
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• pp.65-76
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• 1982

현재(現在) 수입공급(輸入供給)되고있는 농용(農用)트랙터의 고장수리실태(故障修理實態)를 조사분석(調査分析)하여 트랙터의 국산화(國産化) 및 이용합리화(利用合理化)를 위한 기초자료(基礎資料)로 활용(活用)을 목적(目的)으로 1980년(年) 1년간(年間) 8개도(個道) 32개군(個那)에서 기장조사(記帳調査)한 결과(結果)는 다음과 같다. 가. 대형(大型)트랙터의 연평균고장빈도(年平均故障頻度)는 5.0회(回)/대(臺)이고, 소형(小型)은 2.3회(回)/대(臺)로 대형(大型)이 소형(小型)보다 2배이상(倍以上) 고장(故障)이 많았으며, 이용시간당빈도(利用時間當頻度)는 대형(大型)트랙터가 1. 11회(回)/100hr, 소형(小型)은 0.65회(回)/100hr이었다. 나. 전체고장중(全體故障中), 75.6%는 본체(本體)에서 발생(發生)되었으며 24.4%는 작업기(作業機)에서 발생(發生)되었고, 특(特)히 소형(小型)트랙터 작업기고장중(作業機故障中) 쟁기와 로타베이터 고장(故障)이 80%이상(以上)을 차지하였다. 다. 대형(大型)트랙터의 75%, 소형(小型)의 62%가 연(年) 1회이상(回以上)의 고장(故障)이 있었으며, 10회이상(回以上) 발생(發生)된 경우(境遇)도 9%나 되었다. 라. 월별고장발생분포(月別故障發生分布)는 트랙터이용시간(利用時間)과 비례(比例)하는 경향(傾向)을 나타내어 5월(月)에 가장 고장(故障)이 많았다. 마. 운전자(運轉者)의 연령(年齡)이 많거나 학력수준(學歷水準)이 높을 수록 고장빈도(故障頻度)도 높아서 50대(代) 연령(年齡)에 대졸자(大卒者)가 고장(故障)이 가장 많았다. 바. 고장원인(故障原因)은 운전자과실(運轉者過失)이 29.8%, 부품노후(部品老朽)가 30.2%, 품질불량(品質不量)이 20.6%로 나타났다. 사. 연평균수리회수(年平均修理回數)는 5.5회(回)/대(臺)였고 이중 공장수리(工場修理)가 55.6%였으며 자가수리(自家修理)는 44.4%였다. 아. 대당연간수리시간(憂當年間修理時間)은 대형(大型)트랙터가 30.6시간(時間)이었고, 소형(小型)이 19.9시간(時間)이었으며 수리(修理) 1회당소요시간(回當所要時間)은 평균(平均) 3.62시간(時間)으로 나다났다. 자. 대당연간수리비용(臺當年間修理費用)은 대형(大型)이 278천(千)원, 소형(小型)이 70천(千)원 이었고, 이용시간당수리비용(利用時間當修理費用)는 대형(大型)이 621원, 소형(小型)이 198원이었다. 차. 트랙터 본체(本體)의 수리비계수(修理費係數)(Y)는 사용연수(使用年數)(x)'에 대하여 Y=0.752x의 상관(相關)을 가졌으며 총수리비계수(總修理費係數)는 내구년수(耐久年數)가 10년(年)일때 64%가 되었다.

• 대한치과기공학회지
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• 제24권1호
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• pp.9-18
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• 2002

The aim of this study is to propose effective measures for shortage of manpower of dental technology laboratory in Gangwon province by means of examining not only the history of Gangwon association, present condition of transference of members of Gangwon association from 1990, of missing members and annual rate of participation in repair education with setting object of study into Gangwon association under the influence of the Korean Dental Technology Association but also the present condition of opening and closing laboratory, amount of business connection and condition of shortage of manpower and its field with setting object of study into 28 dental technology laboratories. Results from this study are like followings : First, Gagnwon association was established in 1984 as the eleventh in the line of the board, reorganization of board is conducted 8 times up to the eighth in the line of the board in 2001. board is composed of 16 persons including president and operated its term as 3 years. Second, a number of representative and ordinary member of Gangwon association has increased gradually from 1992 to 2001. in aspect of annual rate of participation in repair education, representative's is more higher than ordinary member's overall. the worst rate of whole members' is shown as 47.9% and the its best rate is shown as 92.0%. in addition, 70$\sim$80% rate of participation into repair education is shown most frequently as 8 times of whole 20 times from 1992 to 2001. Third, 29 authorized dental technology laboratories have registered in Gangwon association until march 2002 within 9 cities and counties. in consideration of establishment location. Gangneung city has most amount as 7 laboratories(24.1%), Wonju city has 5(17.2%), Samcheok city and Sokcho city, each has 4(13.8%), Chuncheon city has 3(10.3%), Donghae city and Taeback city, each has 2(6.9%) and Yangyang and Yongwol county, each has 1(3.4%). Fourth, amount of work personnel of laboratory in Gangwon province is 1$\sim$10 persons as the maximum value. 23 laboratories(82.1%) have their own work personnel as amount of 5 and below. in aspect of main business, most of laboratories focus on the Porcelain and Crown. and 16 laboratories(57.1%) have their own expensive equipments such as Milling. its also suggests that 16 laboratories(57.1%) suffer their shortage of working personnel. specifically, 6 laboratories(21.4%) suffer the highest shortage especially in Denture field, Fifth, whole number of Gangwon association is up to 101 members (28 representatives and 73 ordinary members) until December 31th 2001. amount of immune from repair education of Gangwon association until October 2001 is up to 10 persons, and missing members from 1997 is up to 18 persons, suspension of business is up to 4 persons. in aspect of transference from 1990, transfer-in is up to 21 persons and transfer out is up to 16 persons.

• Journal of applied mathematics & informatics
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• 제8권1호
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• pp.199-212
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• 2001

We consider a k-out-of-n system with repair under T-policy. Life time of each component is exponentially distributed with parameter $\lambda$. Server is called to the system after the elapse of T time units since his departure after completion of repair of all failed units in the previous cycle or until accumulation of n-k failed units, whichever occurs first. Service time is assumed to be exponential with rate ${\mu}$. T is also exponentially distributed with parameter ${\alpha}$. System state probabilities in finite time and long run are derived for (i) cold (ii) warm (iii) hot systems. Several characteristics of these systems are obtained. A control problem is also investigated and numerical illustrations are provided. It is proved that the expected profit to the system is concave in ${\alpha}$ and hence global maximum exists.