• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.2
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• pp.59-64
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• 1983

This paper deals with the transient energy method of transient stability analysis of multi-machine power system by improving the transfer conductance, the kinetic energy and the critical transient energy. The tranfer conductance is considered more correctly, the generators of system are seperated to two states (critical and the rest state)and the correction term of critical transient energy (to reference point) is added. This analysis is performed by digital computer simulation and the application of this method to two model systems has shown its superiority to other available methods.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.5
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• pp.335-342
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• 1991

A real-tme nonlinear parameter tomography is pumping wave method. This tomorgraphy has a merit which requires no 180$^{\circ}$ projection datum, while the ray-bending effect is remrkably remained on the reconstructed image. In this paper we intend to compensate this ray-bending effect using the perturbation method. Impulsive pumping wave makes derived compensative term simple form, nad the compensative image is easily obtained. We perform computer simulation to confirm the improvement of corrected imate.

• Bulletin of the Korean Chemical Society
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• v.14 no.1
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• pp.95-100
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• 1993

A noise-induced transition is presented for a bistable system subjected to a multiplicative random force, which is singular at the unstable state. The stationary probability distribution is obtained from the Fokker-Planck equation and the effects of the singularity is analyzed. On the basis of noise-induced phase transition with Gaussian white noise, the relaxation time and the transition rate of the system are evaluated up to the first order correction of D. In the parameter region v < l, the transition rates decrease as the exponent v goes to 1 and as the coefficient of the linear term of the kinetic equation increases.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.166-168
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• 1996

Since interior permanent magnet synchronous motor(IPMSM) has a structure whose magnet is inserted in the rotor, d, q inductances are differ from each other and the motor produces hybrid torque combined allignment term and reluctance term. But, for their complex magnetic path, it is difficult to analyze this type motors by equivalent magnetic circuit method. So, in this paper, the variation of parameters of IPMSM according to the magnet thickness accuired by using the result from finite element method is presented for the sake of effective design process.

• Journal of Chest Surgery
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• v.24 no.3
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• pp.296-302
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• 1991

Coronary artery involvement and myocardial ischemic symptom in Takayasu`s arteritis is uncommon Its presentation as coronary artery narrowing is a potentially lethal but correctable problem. In this case report, a 17-year-old woman of Takayasu`s arteritis with unstable anginal and moderate heart failure is presented. Her coronary angiogram showed that the main trunk of the left coronary artery was moderately narrowed and the proximal portion of the circumflex branch was severely obstructed and the right coronary artery was also narrowed diffusely. Simultaneously the patient had the moderate degree of mitral regurgitation. In order to save her life, the coronary bypass surgery using the saphenous veins and the modified Wooler`s mitral annuloplasty were done urgently, Immediate recovery was uneventful and the postoperative exercise capacity was markedly improved. But the long-term prognosis seems to be uncertain because of 3 reasons: 1] natural progress and complication of Takayasu`s arthritis; 2] fate of the saphenous vein grafts in a relatively young patient with aortitis; 3] residual mitral regurgitation. So long-term follow-up should be needed.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.505-508
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• 1999

Conventional adaptive speed estimators cannot avoid the influence of the non-linear inductance variation under the saturation conditions. Without speed sensors, it is difficult to identify the inductance variation using a reactive power mode because the model contains a term of the rotor speed. In this paper, we propose a novel speed estimator having hybrid architecture in order to estimate both the rotor speed and the inductance variation simultaneously when the motor flux is saturated. Proposed estimator consists of the error between the flux obtained from the stator voltage equation and the flux estimated from the rotor flux observer. Introducing a new correction term into the estimator increases the estimation ability of the conventional speed estimator even though the motor flux is saturated. The convergence of the speed estimation error is examined by simulation Furthermore, the experimental results show the validity of the proposed method.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.55-58
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• 2000

Spectacle diopter of age related changes during 5 years examined 360 eyes(male 79, women 81) who visited optical shop every year. Increasing refractive error of Myopia obviously appeared in young generation which term was elementary school, and then middle and high school. In this study, we concluded that term of correction spectacles should be 4 months in elementary school, 6 months in middle school, and every year in high school.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.4
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• pp.475-480
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• 2004

Function approximation is one of the most important and active research fields in design optimization. Accurate function approximations can reduce the repetitive computational effort fur system analysis. So this study presents an enhanced two-point diagonal quadratic approximation method. The proposed method is based on the Two-point Diagonal Quadratic Approximation method. But unlike TDQA, the suggested method has two quadratic terms, the diagonal term and the correction term. Therefore this method overcomes the disadvantage of TDQA when the derivatives of two design points are same signed values. And in the proposed method, both the approximate function and derivative values at two design points are equal to the exact counterparts whether the signs of derivatives at two design points are the same or not. Several numerical examples are presented to show the merits of the proposed method compared to the other forms used in the literature.

• BMB Reports
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• v.45 no.2
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• pp.120-125
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• 2012

We have developed a biologist-friendly, Java GUI application (GoBean) for GO term enrichment analysis. It was designed to be a comprehensive and flexible GUI tool for GO term enrichment analysis, combining the merits of other programs and incorporating extensive graphic exploration of enrichment results. An intuitive user interface with multiple panels allows for extensive visual scrutiny of analysis results. The program includes many essential and useful features, such as enrichment analysis algorithms, multiple test correction methods, and versatile filtering of enriched GO terms for more focused analyses. A unique graphic interface reflecting the GO tree structure was devised to facilitate comparisons of multiple GO analysis results, which can provide valuable insights for biological interpretation. Additional features to enhance user convenience include built in ID conversion, evidence code-based gene-GO association filtering, set operations of gene lists and enriched GO terms, and user -provided data files. It is available at http://neon.gachon.ac.kr/GoBean/.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.2
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• pp.85-93
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• 2006

Since the SMP(System Marginal Price) is a vital factor to the market participants who intend to maximize the their profit and to the ISO(Independent System Operator) who wish to operate the electricity market in a stable sense, the short-term marginal price forecasting should be performed correctly. In an electricity market the short-term market price affects considerably the short-term trading between the market entities. Therefore, the exact forecasting of SMP can influence on the profit of market participants. This paper presents a new methodology for a day-ahead SMP forecasting using ARIMA(Autoregressive Integrated Moving Average) model based on the time-series method. And also the correction algorithm is proposed to minimize the forecasting error in order to improve the efficiency and accuracy of the SMP forecasting. To show the efficiency and effectiveness of the proposed method, the case studies are performed using historical data of SMP in 2004 published by KPX(Korea Power Exchange).