• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.6
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• pp.331-338
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• 1988

A simple algorithm is presented for solving the thermal unit commitment problem which is one of very important areas in economic operation of power systems. This algorithm is based on simple priority ordering by the unit operation cost and it is shown that the operation cost of chosen sets of generators is the minimum. The proposed method differs from the conventional priority-based formulations in that the unit operation are calculated in every load level. Further the poerating reserve requiements are satisfied by the newly derived analytical security function or the expectation of reserve. The proposed method is proven to be very simple, accurate and efficient in a sample system.

• The Korean Journal of Applied Statistics
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• v.9 no.1
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• pp.153-164
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• 1996

We discussed estimation of parameters using Gibbs sampler under order restriction on the parameters. Two well-knwon probability models, ordered exponential family and binomial distribution, are considered. We derived full conditional distributions(FCD) and also used one-for-one sampling algorithm to sample from the FCD's under order restrictions. Finally through two real data sets we compared three kinds of estimators; isotonic regression estimator, isotonic Bayesian estimator and the estimator using Gibbs sampler.

• Nuclear Engineering and Technology
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• v.15 no.1
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• pp.11-22
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• 1983

The reliability of the Chemical and Volume Control System has been analyzed in a pressurized water reactor. The boration failure was taken to be the top event for this reliability analysis. A detailed fault tree was constructed and the minimal cut sets were derived. It was computed that the unavailability of the Chemical and Volume Control System due to boration failure was 1.497$\times$10$^{-5}$ during plant operation. It was found that the reliability of boric acid transfer pumps were the most important factors in the availability of the Chemical and Volume Control System. As expected, human errors also introduce the high system unavilability.

• Journal of Biomedical Engineering Research
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• v.18 no.1
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• pp.51-64
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• 1997

A dynamic model of the Korean total artificial heart(TAH) which contains a brushless DC motor, all of mechanical components, the pump system with integrated variable volume space(WS) and the circulatory system model including the bronchial circulation were established Two different sets of seven differential equations were separately derived for the left and right systolic period of the Korean TAH operation. Throughout the computer simulation, a full-state fEedback optimal controller that minimizes the power consumption of the Korean TAH and drives the end stage velocity of the energy converter to zero was developed based upon the optimal control theory. Robustness of the controller were also analyzed with the dynamic model of the Korean TAH.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.9 s.90
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• pp.910-918
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• 2004

The vibration analysis of an axially moving membrane are investigated when the membrane has the two sets of in-plane boundary conditions, which are free and fixed constraints in the lateral direction. Since the in-plane stiffness is much higher than the out-of-plane stiffness, it is assumed during deriving the equations of motion that the in-plane motion is in a steady state. Under this assumption, the equation of out-of-plane motion is derived, which is a linear partial differential equation influenced by the in-plane stress distributions. After discretizing the equation by using the Galerkin method, the natural frequencies and mode shapes are computed. In particular, we put a focus on analyzing the effects of the in-plane boundary conditions on the natural frequencies and mode shapes of the moving membrane.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.107-113
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• 2003

This research is to investigate the performance of a flexible matrix composite driveshaft with respect to shaft design parameters such as the number of layers, ply orientations, and material properties. A finite element formulation is utilized to estimate the allowable misalignment under given driving torque, the maximum temperature at steady states, and external damping for ensuring whirling stability under supercritical speed. Results indicate that the system performance can be greatly affected by the shaft laminate parameters, especially the ply orientations. Several sets of shaft parameters that will provide satisfactory overall system performance are derived.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.4
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• pp.448-454
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• 2007

The new tuning rules of the PID controller for the rejection of load disturbance are proposed incorporating with real-coded genetic algorithms (RCGAs). The optimal gain parameters of the PID controller for a first-order plus time delay model are obtained based on a RCGA. Then tuning formula are derived using the tuned parameters sets potential tuning rule models and another RCGA. The performance criteria of the controller are adopted as ISE, IAE and ITAE. A series of simulation are carried out to verify the effectiveness of the proposed tuning rules.

• Journal of the Korean Ceramic Society
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• v.24 no.1
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• pp.47-55
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• 1987

The purpose of this work is to establish the basic calibration data for the efficiency of grinding by investigating the Bond's Work Index employing Korean Kaolin as a reference mateial with the laboratory-scale ball mill. A small ordinary ball mill has a dimension of 133 inside diameter and 144mm long. The analysis of the experimental results in this work sets up a equivalent calibration method with the laboratory-scale ball mill to those with special mill. The theoretical expression, derived from the rate equation proposed by Miwa, is obtained to anticipitate the stable revolution number for the next grinding cycle. The proposed equation is more systematic and acurate than lshihara's empirical equation is more systematic and acurate than lshihara's empirical equation for the measurement of gindability of a ball mill.

• Journal of Information Technology Services
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• v.10 no.1
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• pp.135-149
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• 2011

In this paper, we propose the high-risk group detection model for patients with high blood pressure using case-based reasoning. The proposed model can be applied for public health maintenance organizations to effectively manage knowledge related to high blood pressure and efficiently allocate limited health care resources. Especially, the focus is on the development of the model that can handle constraints such as managing large volume of data, enabling the automatic learning to adapt to external environmental changes and operating the system on a real-time basis. Using real data collected from local public health centers, the optimal high-risk group detection model was derived incorporating optimal parameter sets. The results of the performance test for the model using test data show that the prediction accuracy of the proposed model is two times better than the natural risk of high blood pressure.

• The Plant Pathology Journal
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• v.18 no.6
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• pp.338-341
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• 2002

The potato scab is caused by several species of Streptomyces. Among these species, only pathogenic strains were found to produce thaxtomin A characterized by necrotic bioassay and HPLC. In this study, identification of the pathogenic strains of Streptomyces was performed through the polymerase chain reaction (PCR) by using specific pathogenicity primer sets derived from the nec1 gene sequences of Streptomyces scabies. The expected PCR products were obtained approximately 580 bp and confirmed by sequencing. This PCR technique can be used effectively to identify the pathogenic Streptomyces species, that cause scab on potato tubers.