• Korean Journal of Bronchoesophagology
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• v.4 no.2
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• pp.171-176
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• 1998

Postoperative pain following tonsillectomy remains a significant obstacle to speedy recovery and smooth convalescence. Inadequate analgesia causes poor oral intake and influences the length of hospital stay and ability to return to normal activity. Patient Controlled Analgesia (PCA) is a method of analgesia adminstration that consists of a computer driven pump with a button that the patient may press to adminster a small dose of analgesic drug. The aim of this study was to examine whether Intravenous Patient Controlled Analgesia (IV-PCA) can reduce postoperative pain after tonsillectomy. The 100 patients undergoing tonsillectomy with general anesthesia were divided into two groups. The PCA group patients (n=80) received a mixture of nalbuphine and ketorolac by Walkmed PCA infusor during first 48 postoperative hours. In control group (n=20), the patients received oral acetoaminophen (Tyrenol) regularly and tiaprofenic acid (Surgam) intramuscularly on a p.r.n basis. Analgesic efficacy was evaluated with visual linear analogue scale (VAS) and the adverse effects were evaluated with 4 point scale. The patients of PCA group had less pain than those of control group. The adverse effects in the PCA group were nausea and vomiting. This study suggests that IV-PCA may be safe and effective method of pain control after adult tonsillectomy and is better accepted than oral or intramuscular pain medications.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.3
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• pp.445-450
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• 2015

In the moving target problem, the velocity information of the moving target is very important as well as the high accuracy position information. To solve this problem, active researches are being conducted recently with combine the Time Difference of Arrival (TDOA) and Frequency Delay of Arrival(FDOA) measurements. However, since the FDOA measurement is utilizing the Doppler effect due to the relative velocity between the target source and the receiver sensor, it may be difficult to use the FDOA measurement if the moving target speed is not sufficiently fast. In this paper, we propose a method for estimating the position and the velocities of the target by using only the TDOA measurements for the low speed moving target in the indoor environment with sensor network. First, the target position and heading angle are obtained from the estimated positions of two attached transmitters on the target. Then, the target angular and linear velocities are also estimated. In addtion, we apply the Instrumental Variable (IV) technique to compensate the estimation error of the estimated target velocity. In simulation, the performance of the proposed algorithm is verified.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.102-106
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• 2009

A rapid and sensitive chemiluminescence (CL) method using flow-injection (FI) has been developed for the determination of mandelic acid which is based on the enhancement of mandelic acid to the CL intensity of ${Ru(bipy)_{3}}^{2+}$-Ce(IV) system. The enhancement effect was dependent on the concentration of mandelic acid, based on which, CL system was established for the determination of mandelic acid. The concentrations of ${Ru(bipy)_{3}}^{2+}$+, Ce(IV), and $H_2SO_4$ were optimized. Under the optimum experimental conditions, the linear range and detection limit are 1.46-342.0 ${\mu}g/ml$ and 0.072 ${\mu}g/ml$, respectively. The correlation coefficient (R) was 0.99732. The utility of this method was demonstrated by determining mandelic acid in capsules and human urine sample.

• Journal of the Korean Ceramic Society
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• v.31 no.4
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• pp.427-435
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• 1994

Cu-metallized low firing temperature substrates were synthesized by cofiring green sheet of cordierite-based glass with Cu. By Sol-Gel method, Cu powder was coated with borosilicate gel which should act as a glass frit in Cu paste during cofiring. Theoretical weight ratios of Glass/Cu were controlled to be 2.5, 5, 10 and 15% by varying alkoxide concentrations. Average particle size of coated Cu was 0.629~0.674 ${\mu}{\textrm}{m}$ in comparison to that of as-received Cu(0.596 ${\mu}{\textrm}{m}$), which increased with alkoxide concentration but did not increase above certain concentration. The weight ratios of coated layer were 2.11~5.37%. The properties of Cu-metallized low firing temperature substrate, cofired at 90$0^{\circ}C$ for 1h under H2/N2 atmosphere, were as follows; sheet resistance was 13~43 m{{{{ OMEGA }}/$\square$, adhesion strength was 1.0~2.1 kgf/$\textrm{mm}^2$. From the observations of SEM photographs, the gel coated on Cu performed excellently as a glass frit.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.481-485
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• 2003

To diffuse Zn at solid-state, the $SiO_2/ZnO/SiO_2$ wafers was made by PECVD and RF Spotter. Thicknesses of bottom $SiO_2$ and cap $SiO_2$ was about $500{\AA}$ and about $3500{\AA}$. First test was Diffusion temperatures were $760^{\circ}C$, $780^{\circ}C$, and $800^{\circ}C$, and diffusion times were 1, 2, 3, 4, 5, and 6 hr and 2nd test was Diffusion temperatures were $760^{\circ}C$, $720^{\circ}C$, and $680^{\circ}C$, and diffusion times were 1, 2, 3, 4, 5, and 6 hr. LED chips were fabricated by the diffused wafers at Fab. The peak wavelength of all chips showed about $625{\sim}650\;nm$ and red color Main reason for Iv change was by diffusion temperature not diffusion time. The lower temperature was the higher Iv. We thick that these properties is because of the very high diffusion temperature.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.71-73
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• 2019

The output current of the Grid Connected Inverter (GCI) can be polluted with harmonics mainly due to i) dead time in switches, ii) non-linearity of switches, iii) grid harmonics, and iv) DC link fluctuation. Therefore, it is essential to design the robust Harmonic Compensation (HC) technique for the improvement of output current quality and fulfill the IEEE 1547 Total harmonics Distortion (THD) limit i.e. <5%. The conventional harmonic techniques often are complex in implementation due to their i) additional hardware needs, ii) complex structure, iii) difficulty in tuning of parameters, iv) current controller compatibility issues, and v) higher computational burden. In this paper, to eliminate the harmonics from the GCI output current, a novel Digital Lock-In Amplifier (DLA) based harmonic detection is proposed. The advantage of DLA is that it extracts the harmonic information accurately, which is further compensated by means of PI controller in feed forward manner. Moreover, the proposed HC method does not require additional hardware and it works with any current controller reference frame. To show the effectiveness of the proposed HC method a 5kW GCI prototype built in laboratory. The output current THD is achieved less than 5% even with 10% load, which is verified by simulation and experiment.

• The Korean Journal of Applied Statistics
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• v.35 no.1
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• pp.93-104
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• 2022

In forecasting realized volatility of the major US stock price indexes (S&P 500, Russell 2000, DJIA, Nasdaq 100), internet search volume reflecting investor's interests and implied volatility are used to improve forecast via a deep learning method of the LSTM. The LSTM method combined with search volume index produces better forecasts than existing standard methods of the vector autoregressive (VAR) and the vector error correction (VEC) models. It also beats the recently proposed vector error correction heterogeneous autoregressive (VECHAR) model which takes advantage of the cointegration relation between realized volatility and implied volatility.

• Analytical Science and Technology
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• v.20 no.3
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• pp.251-254
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• 2007

In this study, a convenient, fast and accurate inductively coupled plasma atomic emission spectrometry (ICP-AES) method has been optimized for the determination of osmium in aqueous solutions. The method makes use of the reaction of sulfurous acid with osmium to quantitative conversion of volatile Os(VIII) to non-volatile Os(IV) in the pH range 2-10. The response was found to be stabilized immediately after sulfurous acid reacted with osmium. The precision was calculated to be 0.5-4.5 % (RSD) under various ICP-AES conditions. The detection limit was 2.5-57.7 ng/g based on $3{\sigma}$ of the blank response (n=3) using a concentric flow nebulization.

• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.127-132
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• 2023

In this study, designing of a Type 4 pressure vessel using the filament winding method was conducted. In order to prevent leakage in consideration of the design of the hydrogen storage tank, a liner was designed by applying high-density polyethylene (HDPE), and the composite structure was designed by stacking carbon/epoxy in the hoop and helical directions. As a theoretical approach, the angle of the helical fiber and fiber thickness of each hoop and helix were designed. The safety of the design was verified using the commercial software ANSYS.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.7 no.10
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• pp.47-51
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• 1984

In many forecasting problem, there is little or no useful historical information available at the time the initial forecast is required, The propose of this paper is study on Bayesian Method in forecasting. I : Introduction. II : Bayesian estimation. III : Constant Model. IV : General time series Models. V : Conclusion. The Bayesian procedure are then used to revise parameter estimates when time series information is available, in this paper we give a general description of the bayesian approach and demonstrate the methodology with several specific cases.