• 한국ITS학회:학술대회논문집
• /
• 한국ITS학회 2003년도 제2회 정기총회 및 추계학술대회
• /
• pp.335-339
• /
• 2003

• 한국기술혁신학회:학술대회논문집
• /
• 한국기술혁신학회 2014년도 추계 학술대회 논문집
• /
• pp.404-425
• /
• 2014

• 한국ITS학회:학술대회논문집
• /
• 한국ITS학회 2005년도 제4회 추계학술대회 및 정기총회
• /
• pp.52-57
• /
• 2005

• International Journal of Automotive Technology
• /
• 제6권1호
• /
• pp.45-52
• /
• 2005

Interrupted creep tests for investigating the structural degradation during creep were conducted for a Mod.9Cr-1Mo steel in the range of stress from 71 to 167 MPa and temperature from 873 to 923 K. The change of hardness and tempered martensitic lath width was measured in grip and gauge parts of interrupted creep specimens. The lath structure was thermally stable in static conditions. However, it was not stable during creep, and the structural change was enhanced by creep strain. The relation between the change in lath width and creep strain was described quantitatively. The change in Vickers hardness was expressed by a single valued function of creep LCR(life consumption ratio). Based on the empirical relation between strain and lath width, a model was proposed to describe the relation between change in hardness and creep LCR. The comparison of the model with the empirical relation suggests that about 65% of hardness loss is due to the decrease of dislocation density accompanied by the movement of lath boundaries. The role of precipitates on subboundaries was discussed in connection with the abnormal subgrain growth appearing in low stress regime.

• 한국통신학회논문지
• /
• 제19권10호
• /
• pp.2014-2027
• /
• 1994

이 논문에서는 서비스 우선순위가 다른 2개의 독자적인 입력 스트림을 가지는 큐잉 모델을 연구하였다. 구체적으로 head-of-line 우선 순위가 적용되는 IBP+BP/D/I시스템을 분석하였는데, 여기에는 IBP는 Interrupted Bernoulli Process를 BP는 Bernoulli Process를 표시한다. BP 스트립은 IBP 스트립에 대하여 서비스 우선권을 가진다. 본 논문은 이 우선 순위 큐에 대하여 시스템 상태의 안정상태분포와 각 클래스 별 고객의 대기 시간분포 및 출발시간 간격분포를 구할 수 잇는 정확한 분석방법을 제공하고 있다. 우선 순위가 다른 두 입력스트림의 다양한 파라미터들이 시스템의 성능에 어떠한 영향을 미치는지 보여줄 수 있는 수치적 예들도 제시하였다.

• Journal of the Korean Data and Information Science Society
• /
• 제9권2호
• /
• pp.139-147
• /
• 1998

간여시계열분석을 이용하여 1996년 11월 1일부터 1997년 2월 28일까지 대구시 114유료화정책에 대한 응답비용효과를 분석한 결과, 1997년 1월 1일부터 114전화문의에 대하여 유료화가 실시된 이후 전화문의의 건수는 점진적 영구적으로 감소하였음이 확인되었다. 이 결과는 비록 우리가 처음 기대했던 응답비용의 급진적 영구적 감소효과는 증명하지 못하였지만, 유료화 이후 전화문의의 감소는 업무의 능률성과 서비스 질의 향상에 기여할 수 있을 것으로 기대한다.

• 한국정밀공학회지
• /
• 제21권2호
• /
• pp.168-176
• /
• 2004

Interrupted creep tests were carried out on the Mod.9Cr-1Mo steel in order to investigate the structural degradation during creep. The ranges of creep stress and temperature were from 71 to 167MPa and 873 to 923k, respectively. The change of hardness and tempered martensitic lath width were measured in the grip and gauge parts of interrupted specimens. The lath structure was thermally stable in static conditions, but was not stable during creep, and the structural evolution was enhanced by creep strain. The relation between the change in lath width and strain was described in the from, $\delta$W= a ($W_s-W_o$)$cdot;varepsilon$, where $\varepsilon$ is the strain, $W_o$is the initial lath width, $W_s$ is the final lath width depending solely on stress, and a is the constant of the magnitude of 0.67 $\mu$m /strain. The change in Victors hardness was expressed by a one-valued function of creep life consumption ratio. Based on the empirical relation between strain and lath width, a model was proposed to explain the relation between change in hardness and creep life consumption ratio. The model revealed that about 65$%$ of dislocations in lath structures were eliminated by the migration of subboundaries.

• Journal of Chest Surgery
• /
• 제18권2호
• /
• pp.299-304
• /
• 1985

The partial A-V canal defect consist of ostium primum type atrial septal defect with a cleft mitral anterior leaflet. The clinical findings depend upon the site and size of the left-to-right shunt, the degree of A-V valvular regurgitation, and the degree of resultant pulmonary artery hypertension. We experienced 3 cases of similar condition. The data were as follow: 1. Chest P-A showed increased pulmonary vascularity and moderate cardiomegaly with left atrial enlargement. 2. E.K.G. showed left axis deviation, left atrial enlargement, and left ventricular hypertrophy. 3. Right heart catheterization showed significant 02 step up of SVC-RA and left-to-right shunt. 4. Left ventriculogram showed mitral regurgitation and filling of both atrium. Operative findings were as follow: 1. Primum type atrial septal defect [2x2 cm]. 2. Cleft in the anterior leaflet of the mitral vave. 3. No evidence of ventricular septal defect and tricuspid anomaly. Through a right atriotomy with moderate hypothermia, the mitral cleft was approximated with interrupted sutures. The interatrial communication was closed by a patch of Dacron/pericardium. The patch was attached to junction of the mitral and tricuspid valves along the crest of the ventricular septum using interrupted sutures and the other site using continuous sutures. Postoperative course was uneventful and discharged in good general condition except postoperative bleeding in case 3.

• 한국정보통신학회논문지
• /
• 제4권3호
• /
• pp.549-555
• /
• 2000

본 논문에서는 n개의 버스트 입력 트래픽을 처리하는 이산 시간 큐잉 모형을 분석하기 위한 근사 계산 알고리즘을 제안한다. 입력되는 각각의 버스트 트래픽은 IBP(Interrupted Bernoulli Process)로 모형화된다. 이 알고리즘은 n 개의 입력 프로세스를 하나의 상태 변수로 표시하여 n 개의 입력 프로세스로 표현된 마코프 체인(Markov Chain)의 확률 전이 상태를 단순화한다. 이렇게 단순화된 하나의 상태 변수를 이용하여 큐잉모형의 상태 전이를 표현하고 이를 완전 수치 계산에 의해 해를 구한다. 이러한 절차를 통해 구한 큐 길이, 대기 시간 분포를 시뮬레이션에 의해 구한 값과 비교하여 알고리즘의 타당성을 검증한다.

• Journal of Chest Surgery
• /
• 제17권4호
• /
• pp.657-665
• /
• 1984

Thirty-seven patients had undergone repair of a endocardial cushion defect between 1977 and Aug. 1983 in Seoul National University Hospital. Twenty eight had a partial defect, one intermediate defect and eight complete endocardial cushion defect. Tricuspid cleft was found in 4 cases and mitral cleft was in all p-ECD. Seven patients were of type C anatomy in c-ECD. Four patients had associated major anomalies, including three TOF in c-ECD, one coarctation in p- ECD. In p-ECD patients, the septal defect was closed with patch in all cases and the atrioventricular valvular insufficiency was corrected with MVR in 4 cases, TVR in 1 case and simple interrupted sutures in remainders. In c-ECD patients the septal defect was closed with single patch except one case. The atrioventricular valve was repaired with simple interrupted sutures except one MVR and TVR case. The operative mortality was 14.2% in p-ECD, 44.4% in c-ECD, but recent 3 years [1980-1983] mortality was 8.7% in p-ECD, 20% in c-ECD. More than grade III systolic regurgitant murmur was oted postoperatively in 4 cases of c-ECD and 3 cases of p-ECD. The operative risk factors were preoperative NYHA classification, cyanosis, Rp/Rs, systolic pressure of main pulmonary artery and the degree of regurgitation of atrioventricular valves. The causes of death were low cardiac output syndromes, pulmonary complications and arrhythmias.