• Journal of East-West Nursing Research
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• v.11 no.2
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• pp.116-123
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• 2005

Purpose: The purpose of this study was to analyze the influencing factors on adolescent's self-efficacy. Method: This was a descriptive study. The data were collected from 7th through 12th graders(N=1710) enrolled in middle schools(N=873) and high schools(N=837) in the metropolitan area of Daegu. The instruments had used for this study were the self-efficacy, the life event checklist, and Family APGAR. The data were analyzed using frequency, t-test, Pearson correlation coefficient, and multiple regression analysis. Result: Pearson correlation analysis revealed that there were negative correlations between the self-efficacy and the stress. However, in case of the subjects who recorded higher scores at self-efficacy they showed higher scores at family function. Stepwise multiple regression analysis revealed that powerful predictors of adolescent's self-efficacy were family function and relations of schoolmate. Conclusion: From these results, we can find that the family function and relations of schoolmate were actual factors theta affected the self-efficacy of adolescents. Accordingly, affirmative emotion in family, harmonic communication among family members and sharing housekeeping works is recommended as a useful method in order to enhance the family function, and then the self-efficacy of adolescence will be increased.

• Analytical Science and Technology
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• v.26 no.1
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• pp.51-60
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• 2013

The geometrical parameters, vibrational frequencies, and adiabatic electron affinities (AEAs) for c-$C_nF_{2n}$ (n=8, 9) and $C_{10}F_{18}$ (perfluorodecalin) have been investigated using various quantum mechanical techniques. The possible structures for the neutrals and anions of c-PFA are fully optimized and electron affinities are predicted using energy difference between the neutral and anion. The harmonic vibrational frequencies are also determined and zero-point vibrational energies (ZPVEs) are considered for the better prediction of the electron affinities. The electron affinities are predicted to be 1.18 eV for c-$C_8F_{16}$ (ortho), 1.37 eV for c-$C_9F_{18}$, and 1.38 eV for $C_{10}F_{18}$ (perfluorodecalin) at the MP2 level of theory after ZPVE correction.

• Journal of the Korean Mathematical Society
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• v.44 no.5
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• pp.1163-1184
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• 2007

In this presentation dedicated to the tricentennial birth anniversary of the great eighteenth-century Swiss mathematician, Leonhard Euler (1707-1783), we begin by remarking about the so-called Basler problem of evaluating the Zeta function ${\zeta}(s)$ [in the much later notation of Georg Friedrich Bernhard Riemann (1826-1866)] when s=2, which was then of vital importance to Euler and to many other contemporary mathematicians including especially the Bernoulli brothers [Jakob Bernoulli (1654-1705) and Johann Bernoulli (1667-1748)], and for which a fascinatingly large number of seemingly independent solutions have appeared in the mathematical literature ever since Euler first solved this problem in the year 1736. We then investigate various recent developments on the evaluations and representations of ${\zeta}(s)$ when $s{\in}{\mathbb{N}}{\backslash}\;[1],\;{\mathbb{N}}$ being the set of natural numbers. We emphasize upon several interesting classes of rapidly convergent series representations for ${\zeta}(2n+1)(n{\in}{\mathbb{N}})$ which have been developed in recent years. In two of many computationally useful special cases considered here, it is observed that ${\zeta}(3)$ can be represented by means of series which converge much more rapidly than that in Euler's celebrated formula as well as the series used recently by Roger $Ap\'{e}ry$ (1916-1994) in his proof of the irrationality of ${\zeta}(3)$. Symbolic and numerical computations using Mathematica (Version 4.0) for Linux show, among other things, that only 50 terms of one of these series are capable of producing an accuracy of seven decimal places.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.3
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• pp.269-276
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• 2016

This paper presents a 2.65 GHz Doherty power amplifier with internally-matched GaN HEMT. Internal matching circuits were adopted to match its harmonic impedances inside the package. Simultaneously, due to the partially matched fundamental impedance, input and output matching networks become simpler. Bond wires and parasitic elements of transistor package were predicted by EM simulation. For the LTE signal with 6.5 dB PAPR, the implemented Doherty power amplifier shows a power gain of 13.0 dB, a saturated output power of 55.4 dBm, an efficiency of 49.1 %, and ACLR of -26.3 dBc at 2.65 GHz with an operating voltage of 48 V.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.29 no.1
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• pp.37-40
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• 2018

Background and Objectives : This study aimed to evaluate patients' subjective and objective outcomes after laryngeal microsurgery for benign vocal fold (VF) lesions, and to identify usefulness of surgical treatment. Materials and Methods : The authors reviewed the 102 patients medical records, retrospectively who received laryngeal microsurgery for benign VF lesions from January 2013 to August 2017. Subjective voice were measured using the Voice Handicap Index (VHI). Objective voice were recorded with Multi-Dimensional Voice Program (MDVP) just before surgery, and after at least 3 months of surgery. Results : Benign VF lesions were categorized as VF nodule (n=34, 33%), VF Polyp (n=47, 26%), Intracordal cyst (n=15, 15%), Reinke's edema (n=6, 6%), and VF Papilloma (n=2, 2%). Post-operative voice assessment at VHI scores showed statistically significant reductions in all of functional, physical and emotional parts (p<0.001). MDVP were showed significant improvement of Jitter (P=0.001), Shimmer (p<0.001) and Noise to Harmonic Ratio (NHR) (p=0.001). Conclusion : Laryngeal microsurgery for benign vocal fold lesions is effective treatment with statistically significant improvement at subjective and objective vocal quality assessment.

• Journal of the Korean Chemical Society
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• v.59 no.5
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• pp.387-396
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• 2015

The DFT and ab initio calculations have been performed to elucidate hydrogen interaction of HOOO-(H₂O)_n (n=1~5) clusters. The optimized geometries, harmonic vibrational frequencies, and binding energies are predicted at various levels of theory. The trans conformer of HOOO monomer is predicted to be thermodynamically more stable than cis form at the CCSD(T) level of theory. For HOOO-(H₂O)_n clusters, the geometries are optimized at B3LYP/aug-cc-pVTZ and CAM-B3LYP/aug-cc-pVTZ levels of theory. The binding energy of HOOO-H₂O cluster is predicted to be 6.05 kcal/mol at the MP2//CAM-B3LYP/ aug-cc-pVTZ level of theory after zero-point vibrational energy (ZPVE) and basis set superposition error (BSSE) correction. The average binding energy per H₂O is increased according to adding a H₂O moiety in HOOO-(H₂O)_n clusters up to 7.2 kcal/mol for n=5.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.4
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• pp.368-378
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• 1995

Using two-dimensional depth-integrated tidal computation model. tidal charts of eight major tidal constituents (M$_2$, S$_2$, $K_2$, $N_2$, $K_1$, $O_1$, P$_1$, Q$_1$) are presented for Namhaedo area. Computed distributions of tides were compared with observations. Subsequently, the model was run for one month to derive harmonic constants of tides and tidal currents, thus for formulating predictive data tables. Data tables are then used as PC-based rapid estimation of tides in this area.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.6
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• pp.55-61
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• 2013

In this paper, we describe design and implementation of audio encoder/decoder for voice synthesis. It uses the encoding of difference value of successive samples instead of the original sample value. and has the compression ratio of 4. The function is verified by using FPGA and the performance is measured by the fabricated chip using $0.35{\mu}m$ standard CMOS process. The system clock is 16.384MHz. The measured THD+n is from -40dB to -80dB with frequency variation and the power consumption is about 80mW. It is suited for the mobile application of high audio quality and low power consumption.

• Journal of Power Electronics
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• v.17 no.1
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• pp.96-105
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• 2017

In this paper, a hybrid modular multilevel converter (MMC) topology with an improved nearest level modulation method is proposed for medium-voltage high-power applications. The arm of the proposed topology contains N series connected half-bridge submodules (HBSMs), one full-bridge submodule (FBSM) and an inductor. By exploiting the FBSM, half-level voltages are obtained in the arm voltages. Therefore, an output voltage with a 2N+1 level number can be generated. Moreover, the total level number of the inserted submodules (SMs) is a constant. Thus, there is no pulse voltage across the arm inductors, and the SM capacitor voltage is rated. With the proposed voltage balancing method, the capacitor voltage of the HBSM is twice the voltage of the FBSM, and each IGBT of the FBSM has a relatively low switching frequency and an equalized conduction loss. The capacitor voltage balancing methods of the two kinds of SMs are implemented independently. As a result, the switching frequency of the HBSM is not increased compared to the conventional MMC. In addition, according to a theoretical calculation of the total harmonic distortion of the electromotive force (EMF), the voltage quality with the presented method can be significantly enhanced when the SM number is relatively small. Simulation and experimental results obtained with a MMC-based inverter verify the validity of the developed method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.411-415
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• 2003

In this paper, a reflector type frequency doubler for local oscillator at 24GHz is designed and fabricated with ne71300-N MESFET. Optimum source and load impedances are decided through a multiharmonic load pull simulation technique. A conversion gain ran be improved using the reflector and fundamental and third harmonics are well suppressed with open stub of λ/4 length. Measured results show output power at 0dBm of input power is -3.776dBm, conversion gain 0.736dB, harmonic suppression 41.064dBc, respectively.