• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.4
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• pp.39-45
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• 2001

Maximum and minimum of rendom variables are frequently encountered in the stochastic modelling for various OR problems. We summarize and extend characteristics of maximum and minimum, emphasizing the case in which random variables are independent and all of them except one are distributed exponential. As an application, we derive a transform-free expression for the M/G/1 queue length distribution.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.387-394
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• 2003

A compromise between passive and active control systems has been developed recently in the form of semi-active control systems. Semi-active control systems maintain the reliability of passive control systems while taking advantage of the adjustability of an active control system. This paper presents the results of an experimental study to evaluate the performance of a semi-active orificed fluid damper. The semi-active orificed fluid damper considered is a two-stage damper with normally open solenoid valve. Through a series of experimental tests, characteristics and performance of the damper is investigated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.156-163
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• 2019

In this paper, we present the process of developing an automatic carrying and arming system for testing ammunition. When carrying out shooting tests at a domestic rifle range, most of the ammunition operations are carried out by human manpower The series of test processes, such as transporting, arming and firing of heavy munitions, is repeated by employing human. If the ammunition is loaded via manpower, then problems can occur such as loss of reliability of test results, musculoskeletal disorders of humans and also safety accidents can occur. To address these problems, an automated system was developed for the transport and operation of ammunition. This paper covers the design, manufacture and operation of the developed system. In addition, this study validated the effectiveness of the system as compared to the human operation. Our results show that the developed system can be easily adapted to testing ammunition at a domestic rifle range.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.509-513
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• 1995

A microcontroller-based DC motor control system for a total artificial heart(TAH) was developed. Using a one-chip microcontroller, 87Cl96KB, the design of digital motor speed control system and servo control system is demonstrated. Functionally, the control system consists of a position control unit, a speed control unit, and a communication unit. The performance and the reliability of the developed control system were assessed through a series of mock circulation system experiments.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.205-207
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• 1993

Distribution planning requires comprehensive knowledge about not only distribution but also transmission/subtransmission system expansion plan. At the same time, distribution planning is very time consuming and a series of routine job which involves a lot of experience and efforts of planning engineers. Since the quality of distribution planning depends upon the ability of planning engineers, the economy of investment should be taken into consideration. The object of this study is to establish a computerized distribution planning system which helps distribution engineers finding a new system expansion plan. It provides the engineers with at optimal system expansion plan which satisfies the condition of both reliability and economy.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.483-489
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• 2009

Electrolytic capacitors are used in variety of equipments as smoothening element of the power converters because it has high capacitance for its size and low price. Electrolytic capacitors, which is most of the time affected by aging effect, plays a very important role for the power electronics system quality and reliability. Therefore it is important to estimate the parameter of an electrolytic capacitor to predict the failure. This objective of this paper is to propose a new method to detect the rise of equivalent series resistor(ESR) in order to realize the online failure prediction of electrolytic capacitor for DC output filter of power converter. The ESR of electrolytic capacitor estimated from RMS result of filtered waveform(BPF) of the ripple capacitor voltage/current. Therefore, the preposed online failure prediction method has the merits of easy ESR computation and circuit simplicity. Simulation and experimental results are shown to verify the performance of the proposed on-line method.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.35-38
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• 2005

This paper suggests the method that forecast Dynamic Line Rating (DLR). Thermal Overload Risk (TOR) of next time is forecasted based on current weather condition and DLR value by Monte Carlo Simulation (MCS). To model weather element of transmission line for MCS, we will propose the use of weather forecast system and statistical models that time series law is applied. Also, through case study, forecasted TOR probability confirmed can utilize by standard that decide DLR of next time. In short, proposed method may be used usefully to keep safety of transmission line and reliability of supply of electric Power by forecasting transmission capacity of next time.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.1
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• pp.19-25
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• 1998

Remote fault diagnosis and maintenance system using general telecommunication network is necessary for an effective fault diagnosis and higher productivity of NC machine tools. In order to monitor machine tool condition and diagnose alarm states due to electrical and mechanical faults, a remote data communication system for monitoring of NC machine fault diagnosis and status is developed. The developed system consists of (1) remote communication module among NC's and host PC using PSTN. (2) 8 channels analog data sensing module, (3) digital I/O module for control or NC machine, (4) communication module between NC machine and remote data communication system via RS-232C, and (5) software man-machine interface. Diagnostic monitoring results generated through a successive type inference engine are displayed in user-friendly graphics. The validity and reliability of the developed system is verified to be a powerful commercial version on a vertical machining center through a series of experiments.

• Journal of Korean Society for Quality Management
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• v.9 no.2
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• pp.31-36
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• 1981

This paper deals with the reliability optimization of parallel - in - series system subject to several linear constraints. The model of nonlinear constrained optimization is transformed to a saddle point problem by using Lagrange multipliers. Then Newton - Raphson method is used to solve the resulting problem and these step - by - step solution procedures are programmed in Basic Level II of micro - computer TRS-80. An example which has two linear constraints is solved and the results are analyzed.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.123-129
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• 2014

SCC (Smart Cruise Control) and AEBS (Autonomous Emergency Braking System) are using various types of sensors data, so it is important to consider about sensor data reliability. In this paper, data from radar and vision sensor is fused by applying a Bayesian sensor fusion technique to improve the reliability of sensors data. Then, it presents a sensor fusion verification tool developed to monitor acquired sensors data and to verify sensor fusion results, efficiently. A parallel computing method was applied to reduce verification time and a series of simulation results of this method are discussed in detail.