• Journal of Information Technology Applications and Management
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• v.10 no.4
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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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.3
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• pp.445-450
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• 2009

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

• Journal of Information Technology Applications and Management
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• v.13 no.2
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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.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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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.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.614-614
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• 2006

• International Journal of Reliability and Applications
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• v.17 no.1
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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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• v.18 no.2
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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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.299-305
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• 2016

It is require to design the next generation avionics system while considering applicability under open architecture where standerd communication module is used. In this situation, if the existing schemes cannot guarantee new requirement, new system development is demanded. In this paper, we present design, implementation, and testing procedure for message based middleware to support operational flight program on avionics. System architecture include mission computer (MC) and large area display (LAD) over standard socket communication based on reliable Ethernet. Finally, experimental results demonstrate that the proposed middleware can guarantee real-time with 20msec as well as reliability requirements with no lost packet.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.8
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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.

• Proceedings of the KIEE Conference
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• 2005.11b
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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.