• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.05a
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• pp.289-290
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• 2018

• Journal of applied mathematics & informatics
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• v.40 no.3_4
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• pp.741-751
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• 2022

The object of the present paper is to study some geometric properties of invariant submanifolds of N(k)-contact metric manifold admitting generalized Tanaka-Webster connection.

• Journal of Korean Academy of Nursing
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• v.35 no.6
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• pp.1072-1080
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• 2005

Purpose: This paper was conducted to test the reliability and validity of rd-SLS, developed by Podsakoff, et al. (1993) which measured 'substitutes for leadership'. Method: The subjects were 345 nurses in 5 general hospitals. Cronbach's and the Guttman split-half coefficient were used to test the reliability of rd-SLS. Factor analysis, and the correlations of the rv-SLS and SLS with rd-SLS were used for convergent and discriminant validity. Result: Cronbach's data was 0.76 and the Guttman split-half coefficient was 0.52. Twelve factors evolved by factor analysis, which explained $70.4\%$ of the total variance. This result was similar to previous study results. However, 'Indifference toward organizational rewards'-related items were classified two factors. It was not clear t hat the rd-SLS consisted of 13 concepts(factors). The correlations of the rv-SLS and SLS with the rd-SLS were 0.93 and 0.87 respectively. Conclusion: The rd-SLS showed a moderate degree of validity and reliability. Thus, it is recommended to use the rd-SLS in general nursing organizations for screening for leadership substitutes. In addition, it is necessary to clarify the concept of organizational rewards. In a further study, the factor structure of the rd-SLS may be considered.

• Journal of the Korean Society of Industry Convergence
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• v.14 no.3
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• pp.121-125
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• 2011

EMTP-RV is the very powerful program to analyze the dynamic operation of the power system. To use this package in the large complex power system, it is very important to simplify the power system to simple equivalent network. In our study the 100 MVA STATCOM is placed at 345kV "MIGUM" which is the one of the 345kV substations of the Korean Electric Power System that is consist of more than 1000-bus. MIGUM substation is connected with 7 separated transmission lines to main Korean Electric power system. We developed a new method to simplify the network except the substation that we want to analysis. The power system outside the 345kV substation is modeled into the equivalent network. The loop network outside the substation can be modeled to simplified Thevenin equivalent network. The proposed method is applied to IEEE-14 Reliability Test System and the results shows the effectiveness of the method.

• The Korean Journal of Food And Nutrition
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• v.14 no.6
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• pp.527-531
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• 2001

In order to isolate antioxidant substances from Rhus verniciflua (RV) , the dried stem bark was extracted with water. The crude water extracts was purified by using HPLC method with a DEAE (anionic type) , CN and ODS column. The purified compound remained stable at pH 3.0∼6.0. but unstable above pH 6.5. It was stable at 100$^{\circ}C$ for 4 hours, but still had about 80% of residual activity after treatment at 100$^{\circ}C$ for 5 hours. In antimicrobial test, no inhibition was observed against Gram-positive and negative bacteria. This compound was stronger than that of commercial antioxidant showed that DPPH test, such as BHT, BHC at the same concentration (20 $\mu\textrm{g}$/ml) .

• Magazine of the Korea Concrete Institute
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• v.4 no.4
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• pp.171-179
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• 1992

본 연구에서는 전단-스팬비가 1.5에서 2.5 범위의 고강도 콘크리트 보에 대해 기존 규준식의 안전여부를 확인하고, 사균열강도와 극한전단강도를 결정하기 위해 총 15개의 시험체를 제작하여 실험적 연구를 수행하였다. 주요변수는 전단-스팬비(a/d=1.5, 2.0, 2,5)와 수직전단철근비(Rv=0, 25, 50, 75, 100%, Rv=[$ ho$v / $\rho$v(ACI)] 100)이며, 콘크리트 압축강도(f＇c=747kg/$ extrm{cm}^2$와 인장철근비($\rho$w=0.0377)는 일정하다. 실험결과 본 연구의 전단-스팬비의 범위에서 ACI 318-89 (11-31)식은 일반적으로 수직전단철근에 의해 저항되는 전단강도를 상당히 과소평가하는 것으로 나타났다. 따라서 수직전단철근에 대한 영향이 재고되어야 할 것이다.

• Journal of Electrical Engineering and Technology
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• v.6 no.4
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• pp.439-446
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• 2011

Frequency is an important operating parameter for the protection, control, and stability of a power system. Thus, it must be maintained very close to its nominal frequency. Due to the sudden change in generation and loads or faults in a power system, however, frequency deviates from its nominal value. An accurate monitoring of the power frequency is essential for optimum operation and prevention of wide area blackout. Most conventional frequency estimation schemes are based on the DFT filter. In these schemes, the gain error could cause defects when the frequency deviates from the nominal value. We present an advanced frequency estimation technique using gain compensation to enhance the DFT filter-based technique. The proposed technique can reduce the gain error caused when the frequency deviates from the nominal value. Simulation studies are performed using both the data from EMTP-RV software and the user-defined arbitrary signals to demonstrate the effectiveness of the proposed algorithm. Results show that the proposed algorithm achieves good performance under both steady state tests and dynamic conditions.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.2
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• pp.87-92
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• 2012

Voltage and current phasor estimation has been executed by GPS-based synchronized PMU, which has become an important way of wide-area blackout protection for the prevention of expending faults in a power system. The PMU technique can not easily get the field data and it is impossible to share information, so that there has been used a FNET(Frequency Monitoring Network) method for the wide-area intelligent protection in USA. It consists of FDR(Fault Disturbance Recorder) and IMS(Information Management System). Therefore, FDR must provide an optimal frequency estimation method that is robust to noise and failure. In this paper, we present comparative studies for the frequency estimation method using IRDWT(Improved Recursive Discrete Wavelet Transform), FRDWT(Fast Recursive Discrete Wavelet Transform), and DFT(Discrete Fourier Transform). The Republic of Korea345[kV] power system modeling data by EMTP-RV are used to evaluate the performance of the proposed two kinds of RDWT(Recursive Discrete Wavelet Transform) and DFT. The simulation results show that the proposed frequency estimation technique using FRDWT could be the optimal frequency measurement method, and thus be applied to FDR.

• Journal of Chest Surgery
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• v.16 no.1
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• pp.40-48
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• 1983

Tetralogy of Fallot is characterized by the interventricular septal defect associated with obstruction of the right ventricular outflow. The importance of the latter anatomic malformation was clinically evaluated according to the angiographic measurements of the pulmonary arteries along with the pulmonary valve annulus. Seventy of a total 76 patients operated on during a whole year of 1981 were the patients for clinical evaluation. Fifteen patients died within 1 month after operation with the operative mortality of 21.4%. The young age and the severity of pulmonary arterial hypoplasia were ones among the surgical risk factors at a total corrective surgery of tetralogy. Preoperative angiographic measurements of the pulmonary arteries to speculate the expected postoperative ratio between the left ventricular and the right ventricular pressures were retrospectively calculated according to the formula. The predicted values of P RV/LV greater than 0.5 carried apparenliy higher complication and mortality rates than the group of P RV/LV less then 0.5. The selection of the candidates for either a total correction or the staged operation In tetralogy of Fallot can be evaluated on the preoperative angiographic measurements and the expected Improvements of the clinical results were discussed.

• Journal of Embryo Transfer
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• v.15 no.3
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• pp.237-245
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• 2000

This study was carried out to elucidate whether sperm contain a factor inducing second polar body extrusion and to search for an effective collection method of the sperm factor Thus, sperm extract, dialyzed sperm-extract or liquid chromatographic fractions of sperm extract was microinjected into ovulated oocytes. And the microinjected oocytes were incubated for 24 hours to investigate about the extrusion of second polar body. The results obtained were as follows; 1. Sperm extract significantly increased the second polar body extrusion. 2. Sperm extract showed five major fractions at retention volumes (RVs) 1.25, 1.37, 1.84, 2.10 and 2.67ml after separation with Superose 12 column. These sperm extract fractions did not significantly increase the second polar body extrusion. 3. Dialyzed sperm-extract significantly increased the second polar body extrusion 4. Dialyzed sperm-extract showed three maior fractions at RVs 1.88, 2.14 and 2.77ml after separation with Superose 12 column. Of these fractions, the fraction RV2.14 significantly increased the second polar body extrusion. In conclusion, sperm extract contained a factor inducing the second polar body extrusion and the factor was contained largely in fraction RV2.14 after dialysis and liquid chromatographic fractionation of sperm extract.