• Journal of Chest Surgery
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• v.50 no.3
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• pp.177-183
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• 2017

Background: To improve postoperative outcomes associated with interstitial pneumonia (IP) in patients with lung cancer, the management of the postoperative acute exacerbation of IP (PAEIP) was investigated. Methods: Patients with primary lung cancer were considered to be at risk for PAEIP (possible PAEIP) based on a preoperative evaluation. The early phase of this study was from January 2001 to December 2008, and the late phase was from January 2009 to December 2014. In the early phase, chest computed tomography (CT) was performed for patients for whom PAEIP was suspected based on their symptoms, whereas in the late phase, chest CT was routinely performed within a few days postoperatively. The numbers of possible PAEIP cases, actual PAEIP cases, and deaths within 90 days due to PAEIP were compared between both phases. Results: In the early and late phases, surgery was performed in 712 and 617 patients, 31 and 72 possible PAEIP cases were observed, nine and 12 actual PAEIP cases occurred, and the mean interval from the detection of PAEIP to starting treatment was $7.3{\pm}2.3$ and $5.0{\pm}1.8$ days, respectively. Five patients died in the early phase, and one patient died in the late phase. Significantly fewer PAEIP-related deaths were observed in the late phase (p<0.05). Conclusion: Identifying patients at risk for PAEIP by routine postoperative CT examinations led to the early diagnosis and treatment of PAEIP, resulting in the reduction of PAEIP-related mortality.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.4
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• pp.442-450
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• 2008

In this paper, the phase diverisity in a direct-conversion receiver for a UHF RFID reader is analyzed and the optimal I/Q signal combining methods is presented with respect to tag modulation. At first, fading characteristics of a single channel receiver is shown to prove the importance of phase diversity due to the phase relationship between the backscattered signal and the local oscillator. And the optimal signal combining methods are presented in order to overcome the signal power reduction due to phase diversity. In case of ASK, the power combining method is presented for the optimal I/Q combining. And the arctangent and principal component combining methods using covariance matrix of I and Q channels are presented for the optimal I/Q combining in case of PSK. In order to analyze the performance of suggested methods, the selection diversity and the optimal combining methods are compared. According to analysis and simulation results, the optimal combining methods have a maximum 3 dB SNR enhancement than selection diversity.

• Journal of Fashion Business
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• v.9 no.1
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• pp.120-136
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• 2005

The purpose of this study is to analyze consumers' perceived risk which is shown in the process of purchase phase and consumption phase for the counterfeits of fashion luxury brands and to analyze the interrelationship of each type of perceived risk. The research method of the study used a qualitative approach. 6 informants were selected and then an in-depth interview was held with them. Through this process the data on the perceived risk for counterfeits were collected and analyzed. The results of the study are as follows; The perceived level of psychological risk including counterfeits exposure was extremely high; besides, economic risk and performance risk were also perceived. On the contrary, the perceived level of social risk and fashionability loss were relatively low. The risk perception for counterfeits appeared not only on the purchase phase but also on the consumption phase, and when perceived risk existed on the consumption phase, it had an influence on the level of perceived risk on the next purchase phase. However the psychological risk was continuously perceived on both purchase and consumption phase, even if it did not exist on the consumption phase. Psychological risk, economic risk and performance risk were not independent but interdependent. Moreover, the entire level of perceived risk could be controlled by reducing the level of other perceived risks when a certain type of risk was highly perceived.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.10
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• pp.972-980
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• 1991

LQG/LTR method have a theoretical constraint that it cannot applied to nonminimum phase plant. In this paper we suggest two methods of approximation of minimum phase plant for a given nonminimum phase plant to solve this constraint. Error is described by additive form which can reduce its magnitude in broad frequency range. A optimal approximation method was suggested by using Hankel operator theory and Nehan theory it is shown by example that the methods suggested can resolve the frequency domain constraint arised in Stein and Athans approximation.

• Journal of Korea Foundry Society
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• v.20 no.2
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• pp.129-140
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• 2000

This study aims at the phase-field modeling of the phase transformation in graphitization of the cast iron. As the first step, we constructed a phase-field model including the phases with negligible solubility. Under the dilute regular solution approximation, a simplified version of the phase-field model was obtained, which can be used for the phase transformation related with the stoichiometric phases. The results from the numerical calculation of the phase-field model was in good agreement with the exact analytic solution. The compositional shift due to Gibbs-Thomson effect can be reproduced within 0.5% error in the numerical calculation. The interface velocity, whereas, in numerical calculation of phase-field model appeared to be 15% larger than that from the analytic solution. This error is due to the shift of the interface position in phase-field model from the position with ${\phi}=0.5$.

• The Korean Journal of Applied Statistics
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• v.27 no.1
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• pp.13-20
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• 2014

Phase I Clinical Trials estimate a Maximum Tolerated Dose(MTD). In this paper, an MTD estimation method applied stopping rule is proposed for Phase I Clinical Trials. The suggested MTD estimation method is compared to the Continual Reassessment Method(CRM) method using a Monte Carlo simulation study.

• Communications for Statistical Applications and Methods
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• v.19 no.1
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• pp.57-64
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• 2012

Phase I clinical trials determine the maximum tolerated dose(MTD) of a new drug. In this paper, we proposed a two-stage MTD estimation method by a Stopping rule in a phase I clinical trial. The suggested MTD estimation method is compared to the standard design(SM3) and the continual reassessment method(CRM) using a Monte Carlo simulation study.

• Journal of the Korean Chemical Society
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• v.57 no.2
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• pp.204-209
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• 2013

We calculate in this study the pressure dependence of the frequencies for the Raman modes of A ($A_g$), B ($A_g$, $B_{2g}$) and C ($B_{1g}$, $B_{3g}$) at constant temperatures of 274 and 294K (room temperature) for the solid phase I of benzene. Using the mode Gr$\ddot{u}$neisen parameter of each lattice mode, which correlates the pressure dependence of the crystal volume and the frequency, the Raman frequencies of those modes are computed for phase I of benzene. Our results show that the Raman frequencies of the three lattice modes (A, B and C) increase as the pressure increases, as expected. The temperature effect on the Raman frequencies is not significant, which can be explained by the experimental measurements.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.227-230
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• 1995

This paper presents continuous control concept of unsymmetrical 2 phase induction machine(I.M.). For 2 phase driving of the unsymmetrical I.M., variable voltage and variable frequency inverter is needed. In this paper, a new 12 step PWM 2 phase inverter was proposed. And then, proposed inverter fed 2 phase driving of unsymmetrical I.M. was studied, expecially on average torque and pulsation torque. This system has merits like higher fundamental component and better harmonic characteristics. The simulation was done on this issue and experimental research is on the way.

• Membrane and Water Treatment
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• v.13 no.4
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• pp.201-208
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• 2022

Emulsion Liquid Membrane (ELM) is a prominent technique for the separation of heavy metal ions from wastewater due to the fast extraction and is a single-stage operation of stripping-extraction. The selection of the components (Surfactant and Carrier) of ELM is a very significant step for its preparation. In the ELM technique, the primary water- in-oil (W/O) emulsion is emulsified in water to produce water-in-oil-in-water (W/O/W) emulsion. The water in oil emulsion was prepared by mixing the membrane phase and internal phase. To prepare the membrane phase, the extractant D2EHPA (di-2-ethylhexylphosphoric acid) was used as a mobile carrier, Span-80 as a surfactant, and Paraffin as a diluent. Moreover, the internal (receiving) phase was prepared by dissolving sulphuric acid in water. Di-(2- ethylhexyl) phosphoric acid such as surfactant concentration, carrier concentration, sulphuric acid concentration in the receiving (internal) phase, agitation time (emulsion phase and feed phase), the volume ratio of the membrane phase to the receiving phase, the volume ratio of the external feed phase to the primary water-in-oil emulsion and pH of feed were studied on the percentage extraction of metal ions at 20℃. The results show that it is possible to remove 78% for As(V), 98% for Cd(II), and 99% for Pb(II). Emulsion Liquid Membrane (ELM) is a well-known technique for separating heavy metal ions from wastewater due to the fast extraction and is a single-stage operation of stripping-extraction. The selection of ELM components (Surfactant and Carrier) is a very significant step in its preparation. In the ELM technique, the primary water-in-oil (W/O) emulsion is emulsified to produce water-in-oil-in-water (W/O/W) emulsion. The water in the oil emulsion was prepared by mixing the membrane and internal phases. The extractant D2EHPA (di-2-ethylhexylphosphoric acid) was used as a mobile carrier, Span-80 as a surfactant, and Paraffin as a diluent. Moreover, the internal (receiving) phase was prepared by dissolving sulphuric acid in water. Di-(2-ethylhexyl) phosphoric acid such as surfactant concentration, carrier concentration, sulphuric acid concentration in the receiving (internal) phase, agitation time (emulsion phase and feed phase), the volume ratio of the membrane phase to the receiving phase, the volume ratio of the external feed phase to the primary water-in-oil emulsion and pH of feed were studied on the percentage extraction of metal ions at 20℃. The results show that it is possible to remove 78% for As(V), 98% for Cd(II), and 99% for Pb(II).