• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.202-203
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• 2006

The equipment using the Power electronic device is recently increased in the distribution system, so power utility and customers increase in concerning about harmonics level. Accordingly, The power utility which prepares a measure for the harmonic public standard and manege process must analysis of the harmonics level and the effect on equipment interconnecting distribution system. In the past, the measurement equipment and technique is imperfect, so very difficult to investigate the harmonics and trend. But the improvement of the measurement equipment recently is possible to obtain the data realtime for harmonic analysis. In this paper, we research the measuring domestic harmonic and constructing of DB based on the IEC standard.

• Communications for Statistical Applications and Methods
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• v.6 no.1
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• pp.99-106
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• 1999

This paper considers an imperfect repair model for which the repairable system is maintained preventively at periodic times and is replaced by a new system when a predetermined number of preventive maintenance has been applied. our main objective of this is to determine the optimal number of preventive maintenances before the system is replaced and the optimal length of interval between two consecutive preventive maintenances under a new repair model which is referred to as an ineffective preventive maintenance. Such a model assumes a periodic preventive maintenance in which the system is effectively maintained with a certain probability. Otherwise the system is not improved at all after each maintenance and thus the failure rate remains the same as before. The criteria to determine the optimal number of preventive maintenances and length of period is the expected cost rate per unit time for an infinite time span. We give the explicit expressions for the expected cost rate per unit time. Some numerical examples are presented for illustrative purposes.

• The Korean Journal of Applied Statistics
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• v.23 no.3
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• pp.573-584
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• 2010

This paper considers the differences in the software execution environments in the testing phase and the operational phase to determine the optimal release time and warranty period of software systems. We formulate equations for the total expected software cost until the end of the software life cycle based on the NHPP. In addition, we derive the optimal release time that minimizes the total expected software cost for an imperfect debugging software reliability model. Finally, we analyze the sensitivity of the optimal testing and maintenance design related to variation of the cost model parameters based on the fault data observed in the actual testing process, and discuss the quantitative properties of the proposed model.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.48
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• pp.323-331
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• 1998

This study aims at the introduction to the recall system and its defence strategies for the automobile industry according to the rights and interests protection for consumers, the trade pressure solution of the United States and government's will for the self-certification. Therefore, I make the following proposal in view of the low technological level of Korea's automobile industry, the imperfect means of recall system, the insufficiency of the social recognition and the worst management condition under the IMF system : First, introduction to three steps for self-certification in case of changing the present pype-approval system into the self-certification and its overall operation after 2003. Second, the defence plan of the automobile industry after analyzing the problems coming from the domestic automobile industry.

• Korean Journal of Microbiology
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• v.7 no.3
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• pp.91-106
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• 1969

From a review of the literature it was found that 96 species of fungi have been reported as occurring on the wood of Ulmus americana L., the Amercan elm. In an intensive study of the fungi growing on one American elm log, 60 species were found. Only one had been reported previously on American elm. A second fungus proved to be a hyperparasite of a slime mold. Three members of the Fungi Imperfecti could not be identified and is believed that they may constitute new taxa. In the past, Nasidiomycetes constituted the main group of fungi on American elm wood according to the literature. The Fungi Imperfecti were the largest group in this study in that over half of the species found are imperfect fungi. All of the species encountered in the study were illustrated.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.666-671
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• 1993

A new robust control law is proposed for uncertain rigid robots and two composite robust control laws for flexible-joint manipulators which contain uncertainties. The uncertainty, is nonlinear and (possibly fast) time-varying. Therefore, the uncertain factors such as imperfect modeling, function, payload change, and external disturbances are all addressed. Based only on the possible bound of the uncertainty, a robust controller is constructed for the rigid counterpart of the flexible-joint robot Some feedback control terms are then added to the robust control law to stabilize the elastic vibrations at the joints. To show that the proposed composite robust control laws are indeed applicable to flexible-joint robots, a singular perturbation approach and the stability study based on Lyapunov function are proposed.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.235-238
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• 1998

This paper presents the detection of internal combustion engine's multiple misfire. The primary cause of air pollution by vehicles is imperfect conbustion of fuel. The CARB(California Air Resources Board) have imposed regulations for the detection of misfiring in automotive engines. The OBD-II regulations requir that misfire should be monitored by the diagnostic system, and that the goal of OBD-II is to alert the driver to the presence of a malfunction of the emission control system. Present invention based upon measurements of engine roughness as derived from crankshaft angular velocity measurements with special signal processing method. Crankshaft angular velocity signals are processed by walsh-fourier transform. Experimental work confims that it's possible to apply walsh-fourier transform for the detection of multiple misfires in no-load idle and road testing.

• Journal of Korean Society for Quality Management
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• v.36 no.4
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• pp.77-86
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• 2008

Due to the rapid growth in automated testing and manufacturing systems, screening inspection becomes very attractive. In this paper, we investigate the effects of limited capacity on screening inspection using a surrogate variable. The model is developed under the assumption that the reprocessed and nonreprocessed items are produced by the same manufacturing process and therefore their quality characteristics are independently and identically distributed. Profit models are constructed which involve four price/cost components; selling price, cost incurred by imperfect quality, reprocessing and quality inspection costs. Methods of finding the optimal screening limits are presented, and a numerical example is given. Sensitivity analyses are also performed to study the effect of a process standard deviation on this model.

• Proceedings of the KIEE Conference
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• summer
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• pp.713-715
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• 2004

In an electricity market with an imperfect competition, participants make plans of biddings and transaction strategies to maximize their own profits. The market price and the quantity are concerned with the operation reserve as well as the bidding system and demand curves in an electricity market. This paper presents a model of the combined market , energy market and operating teserve market. The Nash equilibrium is analyzed by using a hi-level optimization , maximization of Social welfare (SW) and maximization of the producers' profits.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.5
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• pp.218-223
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• 2005

Impedance matching characteristics of planar type inductively coupled plasma sources are investigated utilizing the previously reported two-dimensional theory[1] of the anomalous skin effect. Two types of matching networks are considered, and the values of the circuit elements are expressed as functions of various reactor parameter. Also, two cases of perfect and imperfect matching conditions are considered and the functional dependence of the values of matching capacitance and reflection coefficient on the various reactor parameters are investigated using the present circuit model.