• International Journal of Reliability and Applications
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• v.11 no.1
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• pp.17-22
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• 2010

It is desired to estimate the reliability of a system that has two subsystems connected in series where each subsystem has two components connected in parallel. A batch sequential sampling scheme is introduced. It is shown that the batch sequential sampling scheme is asymptotically optimal as the total number of units goes to infinity. Numerical comparisons indicate that the batch sequential sampling scheme performs better than the balanced sampling scheme and is nearly optimal.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.617-621
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• 2004

Miniaturization of subsystems including propulsion systems is recent trends in spacecraft technology. Small space vehicle propulsion is not only a technological challenge of a scaling system down, but also a combination of fundamental flow/combustion constraints. In this paper, physical constraints of micronozzle for cold gas micro-thruster are reviewed and discussed. Method to measure small thrust are also described.

• Journal of the Korea Safety Management & Science
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• v.3 no.2
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• pp.123-131
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• 2001

Reliability calculation of a system is frequently required in industrial, military, and everyday life situations. For such a calculation, it is necessary to specify the configuration of components and subsystems, the failure mode of each component, and the states in which the system is classified as failed. In this paper, we are primary interested in the time to the first failure of a system. And we discuss failure probability of coherent system under various condition, especially focus on probability calculation of subsystem failure before system failure used by Bayes formula. Problem statement and general applications illustrated by several examples.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.368-373
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• 1998

This paper presents a GA-based fuzzy modelling scheme of nonlinear systems. The fuzzy model is a type of the Sugeno-Tagaki's fuzzy model whose consequence parts are described by a linear continuous dynamic equation as subsystem of a nonlinear system. The centers and width of the membership functions of the fuzzy sets defined over the input space and the orders and parameters of subsystems in the consequence parts are adjusted by a genetic algorithm. The effectiveness of the proposed method is verified

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1995.10b
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• pp.249-257
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• 1995

In this paper, we demeonstrate that neural networks can be used effectively for the control of nonlinear dynamical system. To adaptively control a plant, there are two distinct approach. these are direct control and indirect control. Both direct and Indirect adaptive control are trained using static back propagation. In indirect, using the resulting identification model, which contains neural networks and linear dynamical elements as subsystems, the parameters of the controller are adjusted.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1994.11a
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• pp.28-32
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• 1994

에너지이용/발전시스템의 개발은 미래의 급격한 전력수요증가 패턴과 에너지소비에 수반되는 환경문제들의 해소 그리고 에너지절약 측면에서의 이용효율 향상 및 열병합(CHP)시스템 구축 등으로 막대한 투자가 요구되고 있는 분야이다. 이 중 에너지의 효율적인 이용과 환경문제와 연계되어 주목을 받고 있는 연료전지는 연료의 cold burning을 통하여 화학에너지를 직접 전기에너지로 변환시키는 electrochemical devices로서 부수적으로 발생되는 배열을 효과적으로 이용할 수 있는 고효율, 저공해 발전시스템이라고 할 수 있다.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.87.2-87
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• 2001

By the state transformation including independent outputs functions, a nonlinear process model can be decomposed into two subsystems; the one(design model) is described in output variables as new states and used for control system synthesis and the other(disturbance model) is described in the original unavailable states and its couplings with the design model are treated as uncertain time-varying parameters in the design model. Its existence with respect to the design model is ignored. So, the design model is an uncertain time-variant system. Control synthesis based on a reduced design model is a combined ...

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.522-529
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• 1998

In this study, system analysis for a train vehicle with an articulated bogie frame adopted in TGV and TGV-K system is performed. System analysis is carried out as follows. First, modal analysis of each subsystem is performed to obtain the natural frequencies and mode shapes. Then modal analysis, of a whole vehicle is performed to obtain the potential interaction between the subsystems. Finallyforced response analysis, such as driving point mobility, is performed to obtain the dynamic response of specific points.

• Electronics and Telecommunications Trends
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• v.34 no.2
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• pp.101-109
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• 2019

Electrical energy storage (EES) systems store generated electricity in energy storage devices such as batteries and discharge the stored energy when necessary. Individual subsystems of the EES system are being standardized independently; however, a holistic understanding of the whole system is necessary because the EES system is large and complex. IEC TC 120 has developed international standards of EES systems. In this paper, EES systems standards in IEC TC 120, including the planning and installation of EES systems, are presented. Further, ongoing standardization for the application of EES systems to backup power and emergency support is described.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.47.5-47
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• 2002

Some integration methods for the linear subsystems are examined and which algorithm is optimal for real-time simulation is considered. First, a number of typical integration methods for a linear time-invariant system are given. Then, the dynamic errors are shown both from the point of view of characteristic root errors and transfer function errors. After that we compute the dynamic errors of integration and choose the appropriate method for each system.