• Journal of Information Technology Applications and Management
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• 제10권4호
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• pp.185-194
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• 2003

One method to improve S/W quality before releasing after development is to enhance the its reliability, whose direct methodology is to detect and revise the fault through testing. Once the S/W is released because it meets the target reliability, We operational reliability arises. it is obvious the operational reliability different depending on the condition whether it is universal(package) S/W or dedicated S/W. We propose the methodology to calculate operational software reliability of universal and dedicated S/Ws in this paper.

• 한국정보통신학회논문지
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• 제13권3호
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• pp.445-450
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• 2009

소프트웨어를 개발하여 발행하기 전에 품질을 향상시키는 방법으로서 신뢰도를 향상시켜야 하는데, 이의 직접적인 방법으로서는 테스트에 의해 결함을 검출하고 수정해 가는 것이다. 신뢰도가 목표치에 도달하여 발행했을 때, 운영중의 신뢰도 문제가 발생하게 된다. 개발 발행된 소프트웨어 패키지소프트웨어라 불리는 범용소프트웨어냐, 아니면 특수목적을 가진 전용소프트웨어냐에 따라 운영 소프트웨어의 신뢰도가 달라진다. 본 논문에서는 범용소프트웨어와 전용소프트웨어의 운영중의 신뢰도를 산출하는 방법을 제안하고자 한다.

• Journal of Information Technology Applications and Management
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• 제13권2호
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• pp.17-28
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• 2006

The SRGM has been studied under the assumption that S/W reliability can grow as the fault causing failure is removed even during operational phase because the debugging is available. On the other hand, some papers insist on the uniform failure rate during operational phase because the debugging may not be available in case of universal software. The phenomenon, however, has been observed informally many times that the products S/W reliability grows as the time goes by even without any debugging in point of customer view. I propose the simple approaching method to model the S/W reliability phenomenon that the failure rate reduces as time goes on without modifying the existing reliability model in this paper.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.143-146
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• 2005

The software reliability growth depends on the testing time because the failure rate varies whether it is long or not. On the other hand, it might be difficult to reduce failure rate for most of the cases are not available for debugging during operational phase, hence, there are some literatures to study that the failure rate is uniform throughout the operational time. The failure rate reduces and the reliability grows with time regardless of debugging. As a result, the products reliability varies with the time duration of these products in point of customer view. The reason of this is that it accumulates the products experience, studies the exact operational method, and then finds and takes action against the fault circumstances. I propose the simple model to represent this status in this paper.

• 한국통신학회:학술대회논문집
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• 한국통신학회 2006년도 하계종합학술발표회 논문 초록집
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• pp.614-614
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• 2006

• International Journal of Reliability and Applications
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• 제17권1호
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• pp.85-105
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• 2016

In this paper accelerated life testing is incorporated in quality control technique of acceptance sampling plan to induce early failures in high reliability products.Stress under accelerated condition can be applied in constant-stress, step-stress and progressive-stress or combination of such loadings. A ramp-stress results when stress is increased linearly (from zero) with time. In this paper optimum failure-censored ramp-stress accelerated life test sampling plan for log-logistic distribution has been formulated with cost considerations. The log-logistic distribution has been found appropriate for insulating materials. The optimal plans consist in finding optimum sample size, sample proportion allocated to each stress, and stress rate factor such that producer's and consumer's interests are safeguarded. Variance optimality criterion is used when expected cost per lot is not taken into consideration, and bilevel programming approach is used in cost optimization problems. The methods developed have been illustrated using some numerical examples, and sensitivity analyses carried out in the context of ramp-stress ALTSP based on variable SSP for proportion nonconforming.

• International Journal of Reliability and Applications
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• 제18권2호
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• pp.45-63
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• 2017

In this paper, we have formulated optimum Accelerated Life Test (ALT) plan for a parallel system with two independent components using masked data with ramp-stress loading scheme and Type-I censoring. Consider a system of two independent and non-identical components connected in parallel. Such a system fails whenever all of its components has failed. The exact component that causes the system to fail is often unknown due to cost and time constraint. For each parallel system at test, we observe its system's failure time and a set of component that includes the component actually causing the system to fail. The stress-life relationship is modelled using inverse power law, and cumulative exposure model is assumed to model the effect of changing stress. The optimal plan consists in finding out the optimum stress rate using D-optimality criterion. The method developed has been explained using a numerical example and sensitivity analysis carried out.

• 한국정보통신학회논문지
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• 제20권2호
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• pp.299-305
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• 2016

차세대 항공전자 시스템은 표준화 모듈의 데이터통신에 기반한 개방형 아키텍처와 범용성을 위한 새로운 시스템 개발이 요구된다. 본 논문에서는 차세대 항공전자 비행운영 프로그램을 지원하기 위한 메시지 기반 미들웨어를 설계하고 이에 대한 구현 및 테스트를 통한 적용성을 검증한다. 시스템 구성은 임무컴퓨터 (Mission Computer, MC)와 대화면 시현기 (Large Area Display, LAD)를 포함하며 고신뢰의 이더넷기반의 소켓통신이 사용하였다. 마지막으로 실험결과 제안된 방법은 모든 패킷이 20msec의 데드라인에 패킷 손실이 전혀 없이 전달됨으로써 실시간성과 신뢰성 요구사항을 만족시키는 것으로 판명되었다.

• 전기학회논문지
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• 제64권8호
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• pp.1161-1167
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• 2015

Distribution Management System(DMS) ienhancing distribution automation system-based operation efficiency is an optimized system by various operational applications in a distribution network. DMS employs various applications like topology reconfiguration, volt/var control, and restoration at events such as overload, voltage violation, and a fault in a distribution system. An operation efficiency to employ multi-applications as restoration with short-term load forecasting is higher than a performance by a single application; and the applications are accomplished by an operator’s control. Applications’ combination is determined by various alarm information which means critical issues in order to operate a distribution system. Thus, this paper proposes an application management system which can configure application combination, control applications depending on alarm information and check their performance condition. The proposed application management system can be customized by operator easily and have high operation efficiency and reliability because it is worked by reviewed alarm information from operator.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
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• pp.125-128
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• 2005

This paper illustrates potential applications of POM/OPM/BOR, which are used for deterministic reliability evaluation in the operation mode (operational planning and operating) in Korea Power System. Deterministic reliability evaluation in this paper bases the philosophy of the marginality and the limitation of physical quantity (voltage and thermal in main) under contingency analysis. The POM/OPM/BOR tools have been developed by V&R (Vaimann and Research) in USA. Before case studies, main frame and feature of the tools are introduced in brief. Case studies of the actual power system of Korea are demonstrated for checking the application possibility of POM/OPM/BOR.