• Journal of Applied Reliability
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• v.2 no.2
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• pp.85-97
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• 2002

In this paper, partially repairable concurrent spare parts requirement determination problem of newly procured equipment systems is considered. “partially repairable” means that a portion of damaged parts can be recover their function and reused after repairs. A mathematical model is derived for making an CSP requirement determination subject to the constraint of satisfying any given operational availability limitation. We assume that the failure of a part follows a Poisson process and the repair time has an exponential distribution. Using the generalized Lagrange multipliers method, the solution procedure is derived.

• Journal of applied mathematics & informatics
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• v.19 no.1_2
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• pp.311-326
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• 2005

The paper deals with the problem of selective harvesting in a prey-predator model with predator self limitation. Criteria for local stability and global stability for both the exploited and unexploited system are derived. The effort has been considered as a dynamic variable and taxation as a control instrument to protect the fish populations from over exploitation. Finally, the optimal taxation policy is discussed with the help of control theory.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.20-23
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• 2002

A Switched Reluctance Generator attracts much attention because of high efficiency, simple cont-reliability, with traction drive. But the theories that have been adopted as SRG control methods up to the present are complicated. This paper proposes reference current limitation strategy for stable generation of SRM. The proposed method is verified by simulation and experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.521-526
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• 2003

In this study the traffic noises were investigated for the subjective allowing limitation ion and the testified classes, 7 point scale was selected to evaluate the annoyance level with vocabularies. As a result, 'relatively annoying' is the most suitable expression for the allowing 1imitation, and the sound pressure levels for the traffic was 44.4㏈.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.766-771
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• 2003

In this study the drainage noises were investigated for the subjective allowing limitation and the testified classes. 7 point scale was selected to evaluate the annoyance level with vocabularies. As a result, 'a little annoying' is the most suitable expression for the allowing limitation, and the sound pressure levels for the urinal was 43.5㏈ and the bathtub was 44.6㏈.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.2
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• pp.26-32
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• 2013

The rotorcraft makes lift and control forces by the rotor thrust. At the development phase of the rotorcraft, the operational limitations have to be established. And it shall be demonstrated to operate the rotorcraft safely within the limitations. This paper introduces establishment and evaluation results of operational rotor speed limitations for the medium class utility rotorcraft. And it shows the follow-up activities after design changes of rotor speed indicators and aural warning systems for implementing the rotor speed limitations.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.2
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• pp.318-329
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• 1994

This paper deals with the finite wordlength effect on the performance of digital PID controllers. The finite wordlength, one of the major limitation factors in digital controllers, results on two kinds of quantization error : the signal quantization error and the coefficient quantization error. This paper derives the variance of the plant output due to the signal quantization error. Using stability margins as performance criterion, the statistical wordlength concept is adopted for coefficient wordlength selection. Finally, the experimental results exhibit satisfactory performance of the digital PID controller with statistical coefficient wordlength.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.5
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• pp.264-268
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• 2000

In discuss how the existing study results that decide optimum release time are rational and reasonable, considering the cost and reliability simultaneously in this paper. As a study method this paper examines the proposed results and their methodologies centering around the existing related papers for the general cost-reliability optimal release policies, especially their limitation for the derived results.

• Journal of electromagnetic engineering and science
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• v.4 no.2
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• pp.68-71
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• 2004

The limitation of telegrapher's equations for analysis of nonuniform transmission lines is investigated here. It is shown theoretically that the input impedance of a nonuniform transmission line cannot be derived uniquely from the Riccati equation only except for the exponential transmission line of a particular frequency-dependent taper. As an example, the input impedance of an angled two-plate transmission line is calculated by solving the telegrapher's equations numerically. The numerical results suffer from larger deviation from its rigorous solution as the plate angle increases.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.6-10
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• 2002

A Switched Reluctance Generator attracts much attention because of high efficiency, simple controllability, with traction drive. But the theories that have been adopted as SRG control methods up to the present are complicated. This paper proposes reference current limitation strategy for stable generation of SRM. The proposed method is verified by simulation and experiments.