• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.6
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• pp.52-58
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• 2008

In this paper, electrically small square loop antenna with SRR (Split Ring Resonator) cover structure is built and tested. The proposed antenna has very small size, ka = 0.34 by Chu limit. The experimental result shows that the resonant frequency and impedance bandwidth($VSWR{\leq}2$) are 906MHz and 5.8MHz (901.7 - 907.5MHz), respectively. The proposed antenna is matched and designed by equivalent circuit model. The proposed antenna is fabricated simple structure without additional matching network and printed on a Teflon substrate without ground plane. Therefore, it has advantages of low cost, small size, and light weight and will be applied to wireless communication systems where small antennas are required.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.3
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• pp.1-8
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• 2000

This paper presents a simulation model of the Quadrature detector to demodulate FSK signal, which is widely used in wireless paging system for its simple hardware implementation and economics of It fabrication. Quadrature detecter has nonlinear phase characteristic for changes linear changes of input signal frequency. So until now Quadrature detector system analysis remained a difficult problem and performance analysis has not been carried out adequately On these backgrounds, this paper presents the FSK signal demodulation process using Quadrature detector and optimal performance derived from digital simulation technique. First, PSN(Phase Shift Network) which is composed of analog RLC tank circuit is transformed into its equivalent digital transfer function using First-order-hold theorem. Though the demodulated outputs of the Quadrature detector for 4FSK are 4-level signals, only 2 comparators are used and it is shown that optimal performance can be obtained by choosing operation parameter Q value and threshold level decision which are proposed herein.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.30-38
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• 1998

A new frequency weighing sensor was applied to grow Bi12GeO20 crystals in the auto-di-ameter control system of Czochralski method. The rotation rate was varied in the range of 23 to 21 rpm to preserve flat interface in a given heat configuration. To prevent the constitutional super-cooling from the evaporation loss, 105% stoichiometric amount of Bi2O3 was employed, equivalent to 6.18 molar ratio of Bi2O3 to GeO2. Transparent and light brown Bi12GeO20 single crystal in uniform diameter was grown. The dislocation density was determined to be 103/cm2 corresponding to the optical quality in commercial applications. The grown crystal measured diameter 25 mm and length 70 mm and the preferred growth direction was confirmed to be <110>.

• The Journal of Korean Academic Society of Nursing Education
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• v.23 no.1
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• pp.27-36
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• 2017

Purpose: The purpose of the non-equivalent control group pretest-posttest study was to test the effects of self-directed nursing practice using peer-tutoring, on the level of confidence, performance and learning satisfaction of nursing students in practicing core nursing skills. Methods: The data were collected from 80 junior nursing students at a nursing college in Daejeon before and after 3 weeks of intervention on practicing six core nursing skills, according to the highest order of priority. The subjects were divided into the peer-tutoring practice group (PTPG, n=40) and the lecturer-guided practice group (LGPG, n=40). The data were analyzed using mean, frequency, and t-test. Results: The PTPG scored statistically higher than the LGPG on the performance of 'indwelling urinary catheterization' and 'wearing protection equipment while entering quarantine room & disposing waste'. The PTPG scored statistically higher than the LGPG on the confidence of 'indwelling urinary catheterization' and 'inserting intravenous catheterization'. The PTPG scored statistically higher on learning satisfaction than LGPG. Conclusion: The results showed that self-directed nursing practice using peer-tutoring could be effective for nursing students in improving proficiency in core nursing skills and might be applied to core nursing skills training.

• Korean Journal of Optics and Photonics
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• v.17 no.2
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• pp.149-158
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• 2006

We have analyzed various tolerances of the multi-configurative microscopic system for inspecting the wire-bonding of a reed frame by using the Gaussian bracket method and the equivalent lens method. The tolerances for the curvature and the thickness, which are axial symmetric tolerances, are given by varying the back focal length within a fecal depth under diffraction-limited conditions. Moreover, by using the trial and error method, the axial non-symmetric tolerances for decenter and tilt are established by assigning the 5% variation of MTF(modulation transfer function) at the spatial frequency of 50 lp/mm and at the field angle of 0.7 field. As the tolerances with the most probable distribution are distributed within the range of the decay rate of less than 5% independent of the probability distribution of tolerances, we can achieve completely the desired design performances of the multi-configurative microscopic system by using the various ranges of these tolerances.

• Journal of Fashion Business
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• v.16 no.2
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• pp.44-61
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• 2012

The 21st century directs designomics to achieve wealth by designing old beyond a simple recognition of the importance of culture. One of the representative local cultures of Gyeongnam is Gaya culture. The Gaya period had over 600 years history with rich and excellent iron manufacturing skill and advanced pottery culture. It is the very time to reevaluate the importance of Gaya equivalent to the Three Kingdoms in our ancient history which was has been so far ignored and isolated. In order to develop unique and excellent culture of Gaya as local fashion cutural goods, questionnaire survey on the recognition of Gaya culture and cultural goods purchasing status had been conducted to target visitors of Representative National Museum. Data Analysis Using SPSS 18.0 Win was performed with frequency analysis and t-test. As to the questionnaire survey, important criteria for purchasing in case of buying cultural goods could be found and the residents in Gyeongnam had higher recognition of developing cultural goods by the motif of Gaya relics. 'Mounted vessel in the shape of warrior on horseback(12.4%)' and 'Chariot wheel-shaped Pottery(10.8%)' were selected the most suitable motif, 'Cellphone strap(11.0%)' and 'key holder(10.2%), 'cup (7.2%)'were selected the most suitable item of cutural goods. These will be actively reflected in the development of fashion cultural goods design applying Gaya relics.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.18-26
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• 2001

In this paper, the resonant characteristics and modes of the film bulk acoustic wave resonator (FBAR) used in 1~2 GHz frequency region are analyzed by it's input impedance which was calculated by three dimensional finite element method formulated as eigenvalue problem using electro-mechanical wave equation and boundary condition. It was extracted that the resonant and the spurious characteristics considering the effects of electrode area and shape variation and unsymmetry of upper and lower electrode. Those effects couldn't be analyzed by on dimensional analysis, e.g. Mason equivalent model. The simulation result was confirmed by comparing with the simulation data from Mason model analysis and the measured data of the ZnO FBAR fabricated using micro-machining technique. Also, through the simulation of the area variations of FBAR, it was obtained that the optimum ratio of length and thickness is 20:1 and the minimum ratio is 5:1 to operate thickness vibration mode.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.7
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• pp.768-773
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• 2012

A branch-line hybrid using microstrip artificial transmission lines(ATLs) with slotted-triangular patches is proposed. The proposed artificial transmission line is compact in structure as well as easy to adjust the characteristic impedance and electrical length of equivalent transmission line by changing the slot's parameters; hence, it is useful for miniaturizing conventional transmission lines. The designed branch-line hybrid, because of the use of the right angled isosceles triangular shaped artificial transmission lines as building blocks, has no useless empty space, and hence optimally miniaturized. A fabricated 3 dB branch-line hybrid shows the coupling variation of ${\pm}0.5$ dB and the phase difference between two output ports of $91^{\circ}{\pm}4^{\circ}$ within 15 % bandwidth at 2.45 GHz center frequency. The size of proposed branch-line hybrid is only 38% of the conventional branch-line hybrid.

• The Korean Journal of Emergency Medical Services
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• v.22 no.1
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• pp.49-59
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• 2018

Purpose: The purpose of this study was to develop an assistant device for the promotion of bag-valve-mask ventilation based on a non-equivalent control group pre-test and post-test design. Methods: The experimental tool was a mask assistance device developed by the researchers. Data were analyzed using SPSS 21.0 with the cardiopulmonary resuscitation (CPR) evaluation program from August 18 to 30, 2016. The research tools included general, hand-related, and ventilation-related characteristics. Results: Before and after using the mask assistance device, the tidal volume increased by 64 mL (p<.001) from 461.76 mL to 525.86 mL. The tidal volume for control was 477.86 mL, and there was a statistical difference (p<.05). The ventilation frequency in device users was 10 times per minute for a total of 20 ventilations with before 10.65 after 10 times, and that of the control group was before 10.36 times after 10 times; there was no difference in both groups(p>.05). The accuracy of the assistance device was $81.72{\pm}30.86%$, which was a very high value. However, the accuracy of ventilation in the control group with no assistance device was $18.97{\pm}32.44%$, which was a very low accuracy rate. Conclusion: This study's results suggested utilizing the newly-developed mask assistance device in CPR, and showed increases in tidal volume and accuracy of ventilation using the bag-valve-mask ventilation equipment. The general and hand-related characteristics did not have any effect, so the use of the device proved to increase the efficacy in all users.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.4
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• pp.49-53
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• 1999

In this study, the characteristics of the structure of buried type capacitor for RF multi- chip-module are investigated. We developed many kinds of structures to minimize the space of capacitor in module and the value of parastic series inductance without any loss in capacitance, and in this procedure the effect of vias especially position, size, number length are analyzed and optimized. This characteristics of structures are checked through HFSS(high frequency structure simulator) of HP, and the value of parastic series inductance is calculated by equivalent circuit analysis. And ensuing the result of simulation, we made buried type capacitors using LTCC (low temperature cofired ceramic) material. In measurement of this sample, we found out the effective and precise method can be applied to buried type and characteristics of vias and striplines added for measuring are quantified.