• 전자공학회논문지S
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• 제35S권1호
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• pp.29-38
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• 1998

We summarize, in this paper, that we have learned from the slftwar reliability analysis of a large switching software composed of functional blocks which form slotware units. To determine the time of management activity related to sopftware reliability growth, we review the process of detection and correction of software failures. Also we apply the two softwre reliability frowth model, Goel-Okumoto and S-shaped model, to estimate the global software reliability growth to a set of failure found during period of the system test. The analysis methods and results can be applied to other large software development projects.

• Journal of Chest Surgery
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• 제21권1호
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• pp.62-69
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• 1988

In the department of chest surgery of WonKwang university hospital, mechanical valve replacement was performed in 51 cases from June 1985 to September 1987. Among these, 32 cases were mitral valve replacement, 4 cases were aortic valve replacement, and 15 cases were double valve replacement. 26 cases were male and 25 cases were female and age distribution ranged from 16 years old to 63 years old. Early death within 30 days after operation was 2 cases [3.9%] and causes of death were right heart failure [1] and right ventricular wall rupture [1]. Among 49 early survivors, 2 cases of late death were developed and the causes of death were cardiomyopathy [1] and ventricular arrhythmia [1] Anticoagulant therapy was done with warfarin sodium to the level of 1.5-2 times of normal prothrombin time [20-40%] in 47 survivors. Symptomatically, 93.6% of preoperative NYHA functional class III or IV were converted to the NYHA functional class I or II during follow up.

• Nuclear Engineering and Technology
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• 제51권5호
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• pp.1289-1296
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• 2019

Non-functional requirements plays a critical role in designing variety of applications domain ranges from safety-critical systems to simple gaming applications. Performance is one of the crucial non-functional requirement, especially in control and safety systems, that validates the design. System risk can be quantified as a product of probability of system failure and severity of its impact. In this paper, we devise a technique to do the performance analysis of safety critical and control systems and to estimate performance based risk factor. The technique elaborates Petri nets to estimate performability to ensure system dependability requirements. We illustrate the technique on a case study of Nuclear Power Plant system. The technique has been validated on 17 safety critical and control systems of Nuclear Power Plant.

• Asian Journal of Innovation and Policy
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• 제1권2호
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• pp.168-199
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• 2012

Studies on innovation point towards the need for both in-house research and development (R&D) capabilities along with collaborations with external organisations or linkages with other firms, universities and research institutes. The argument is that innovation is not just a firm specific factor but requires support from several other factors which in turn involves developing linkages with various actors/institutions as sources of resources and/or knowledge for innovation. This paper presents findings from an exploratory study about the Malaysian biofuel sector as an innovation system. Instead of using the neo-classical approach and proposing policy interventions based on traditional market failure rationale (Bergek et al., 2008a), the functional analysis of the technological innovation systems (TIS) approach is used to analyse the biofuel sector in Malaysia to help reveal the strengths and weaknesses in terms of its fulfillment of seven critical functions which are necessary for the generation and commercialization of a product. In addition an attempt is made to reveal the inducement and blocking mechanisms affecting the Malaysian biofuel TIS and the seeking of improved poor functionality. These functional aspects of the Malaysian biofuel sector are analysed in different phases of its development to gain an understanding of the different institutions and their functions at different phases of the development of the innovation system.

• 전기학회논문지
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• 제66권9호
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• pp.1373-1378
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• 2017

This paper presents a basic ECU(Electronic Control Unit) hardware development procedure for the functional safety of in-vehicle network systems. We consider complete hardware redundancy as a safety mechanism for in-vehicle communication network under the assumption of the wired network failure such as disconnection of a CAN bus. An ESC (Electronic Stability Control) system is selected as an item and the required ASIL(Automotive Safety Integrity Level) for this item is assigned by performing the HARA(Hazard Analysis and Risk Assessment). The basic hardware architecture of the ESC system is designed with a microcontroller, passive components, and communication transceivers. The required ASIL for ESC system is shown to be satisfied with the designed safety mechanism by calculation of hardware architecture metrics such as the SPFM(Single Point Fault Metric) and the LFM(Latent Fault Metric).

• Journal of Chest Surgery
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• 제26권11호
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• pp.827-832
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• 1993

From Jan 1982 through Dec.1991, thirty-three DeVega`s tricuspid annuloplasties were performed in association with mitral and combined mitral and aortic valve disease. Preoperatively,all of the patients were in NYHA functional class III or IV.There were one early death and 4 patients died during follow up period of 18 to 138 months [ mean follow up : 67.3 months ]. Nine patients required reoperation because of biological mitral valve failure at 4.7 to 11 years after tricuspid annuloplasty[TAP]. Among these patients,2 cases needed for reoperation of TAP due to loosening of suture material. Twenty four [86%] of the survivors were in NYHA functional class I or II after TAP.The actuarial survival rate for the TAP was 74% at 138 months. Rt atrial pressure of 9 reoperation cases were significantly decreased [P<0.05] compared with initial Rt.atrial pressure [ Mean period; 93.6 months].Doppler echocardiographic studies for tricuspid regurgitation were performed in 15 cases after TAP [Mean period: 42.3 months].These results showed significantly reduced [P<0.01] tricuspid annulus diameter and tricuspid regurgitation distance [ P<0.05 ].Our surgical experience that the DeVega`s TAP is a simple,safe,effective procedure and resulted in good hemodynamic improvement with moderate to severe functional tricuspid regurgitation.

• Journal of Chest Surgery
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• 제21권5호
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• pp.850-855
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• 1988

From July 1983 to June 1988, twenty six patients underwent mitral valve repair for pure mitral stenosis[21 patient] or for mitral stenosis with a mild degree of regurgitation[5 patient] at Chonbuk National University Hospital. All patients underwent open mitral commissurotomy and 17 patients required to additional procedures for relief of obstructive subvalvular lesion. There was no operative death. The patients were followed from one to sixty months[mean 24. 1Mo.] One late death occurred due to cardiac and renal failure 10 month postoperatively. Of the 25 surviving patients at the time of follow-up, 17 patients[68%] were in NYHA functional class I and 8 patients[32%] were in class II.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(I)
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• pp.151-155
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• 2003

In this paper, as the first step to assess and enhance the reliability of Korea High Speed Train, electric traction system is selected and reliability analysis is carried out. The electric traction system is classified into subsystems and functional block diagrams and reliability block diagrams are drawn. Expressions to calculate the reliability are deducted and Mean Kilometer Between Service Failure is calculated using the trial test results on the track. Calculated results show reliability growth of the electric traction system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.255-261
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• 2007

In this paper we introduce the method, procedure and result of RAM prediction for interlocking system which is applied for AREX signaling system. For RAM prediction, we breakdown the interlocking system to the LRU level and select the LRUs of which failure can cause the service delay. The prediction of reliability is based on the Reliability Block Diagram which is the functional diagram composed of selected LRUs and finally, the availability of interlocking system is estimated from the combination of reliability and maintainability.

• Journal of Chest Surgery
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• 제11권4호
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• pp.535-540
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• 1978

Between January 1974 and November 1978, 23 cases of double valve replacement were done in the Department of Thoracic Surgery, Seoul National university Hospital. All had symptoms of rheumatic valvular heart disease and belonged to functional class III or IV according to NYHA classification. Among 23 cases, mitral and aortic valves were replaced in 14, and mitral and tricuspid valves in 9 cases. Six operative deaths [26%] and 4 late deaths [23%] were found. In the former group 5 and in latter one operative death were noted. Main cause of operative death was low cardiac output syndrome due to myocardial failure. Among 4 late deaths, 2 were caused by thromboembolism, one by bacterial endocarditis, and one by arrhythmia.