• Journal of Distribution Science
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• v.11 no.6
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• pp.13-19
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• 2013

Purpose - This study aims to predict the audit reports of listed companies on the Tehran Stock Exchange by using meta-heuristic algorithms. Research design, data, methodology - This applied research aims to predict auditors reports' using meta-heuristic methods (i.e., neural networks, the ANFIS, and a genetic algorithm). The sample includes all firms listed on the Tehran Stock Exchange. The research covers the seven years between 2005 and 2011. Results - The results show that the ANFIS model using fuzzy clustering and a least-squares back propagation algorithm has the best performance among the tested models, with an error rate of 4% for incorrect predictions and 96% for correct predictions. Conclusion - A decision tree was used with ten independent variables and one dependent variable the less important variables were removed, leaving only those variables with the greatest effect on auditor opinion (i.e., net-profit-to-sales ratio, current ratio, quick ratio, inventory turnover, collection period, and debt coverage ratio).

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.3
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• pp.389-398
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• 2002

The mixed mode problem (I and II) of a peny-shaped interface cracks in remote tension loading on a bi-material cylinder is studied using finite element method. The energy release rates for the tip of the crack in the interface were calibrated for several different moduli combinations and crack ratios using the modified crack closure integral technique and J-integral method, with numerical results obtained from a commercial finite element program. Numerical results show that non-dimensional value of$\sqrt{G_{II}E^*}/\sqrt[p]{\pi a}$ increases as the crack size or moduli ratio increases. Meanwhile, non-dimensional value of$\sqrt{G_{I}E^*}/\sqrt[p]{\pi a}$ decreases as the moduli ratio increases, but above the moduli ratio of 3 its value decreases then increases again as the crack size increases. Reliability of the numerical analysis in this study was acquired with comparison to an analytical solution for the peny-shaped interface crack in an infinite medium.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.45.2-45.2
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• 2019

The main-belt asteroid (5247) Krylov is known as a Non-Principal Axis (NPA) rotator. However, the shape model and spin state of this asteroid were not revealed. The physical model of an asteroid including spin state and shape is regarded to be important to understand its physical properties and dynamical evolution. Thus, in order to reconstruct the physical model of Kryolv, we applied the light curve inversion method using not only the optical light curves observed with ground-based telescopes in three apparitions during 2006, 2016, and 2017, but also the infrared light curves obtained with the Wide-field Infrared Survey Explorer (WISE) in 2010. We found that it is rotating in Short Axis Mode (SAM) with the rotation and precession periods of 368.71 hr and 67.277 hr, respectively. The orientation of the angular momentum vector is (298°, -58°) in the ecliptic coordinate system. The ratio of moments of inertia of the longest axis to the shortest axis is I_a/I_c = 0.36; the ratio of moments of inertia of the intermediate axis to the shortest axis is I_b/I_c = 0.96. Finally, the excitation level of this asteroid is found to be rather low with a ratio of the rotational kinetic energy to the basic spin state energy as E/E₀ ≃ 1.024. We will briefly discuss the possible evolutionary process of Krylov in this presentation.

• The Journal of Korean Medicine
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• v.37 no.1
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• pp.114-124
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• 2016

Objectives: The aim of this study is to find what effects both the posture of sitting and standing and the ratio of inhalation and exhalation (I/E) have on heart rate variability (HRV) Methods: We made two breathing sets with 4:6 or 6:4 ratios of I/E at 0.1 Hz of respiratory frequency and sitting or standing position. There was 20 minute-rest between sets. Each set include 5 minute-3 breathings as follows: 0.1Hz paced breath with sitting, usual breathing with standing and 0.1Hz paced breath with standing. Five minute-usual breathings with sitting as basal lines were exerted before and after these 3 breaths. Electrocardiogram-recording was exerted from 73 healthy participants (37 men and 36 women) who carried out two sets of breathings. Finally, HRV indices were analyzed of 62 participants (32 men and 30 women). Results: In 4:6 maintaining the same posture, SDNN were statistically increased, while mean heart rate(HR) were not changed. In 6:4, mean HR, SDNN were statistically increased. When changed from sitting to standing, in 4:6, SDNN were statistically decreased and mean HR was increased. However, in 6:4 during change of posture, SDNN were also statistically decreased and mean HR was statistically decreased. There was no statistical change of HF during 4:6 or 6:4 ratios of I/E moving from sitting to standing position. Conclusions: For increasing HRV, breathing in low respiratory rate with sitting was recommended regardless of ratio of I/E. In changing from sitting to standing, 4:6 may increase mean HR, and 6:4 may decrease mean HR.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.231-232
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• 2016

This paper investigates the design of multi-winding coupled inductor for minimum inductor current ripple. Based on the general circuit model of coupled inductor together with the operating principles of dc-dc converter, the relationship between the ripple size of inductor current and the coupling factor is derived under the different duty ratio. The optimal coupling factor of n-phase multi-winding coupled inductor which corresponds to a minimum inductor ripple current becomes -(1/n-1), i.e. a complete inverse coupling without leakage inductance, as the duty ratio of steady-state operating point approaches 1/n, 2/n, ${\cdots}$ or (n-1)/n. In an opposite manner, the optimal coupling factor value of zero, i.e. zero mutual inductance, is required when the duty ratio of steady-state operating point approaches either zero or one. Therefore, coupled inductors having optimal coupling factor can minimize the ripple current of inductor and inductor size.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.88-89
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• 2017

This paper investigates the design of multi-winding coupled inductor for minimum inductor current ripple in rapid traction battery charger systems. Based on the general circuit model of multi-winding coupled inductor together with the operating principles of dc-dc converter, the relationship between the ripple size of inductor current and the coupling factor is derived under the different duty ratio. The optimal coupling factor which corresponds to a minimum inductor ripple current becomes -(1/n-1), i.e. a complete inverse coupling without leakage inductance, as the steady-state duty ratio operating point approaches 1/n, 2/n, … or (n1)/n. In an opposite manner, the optimal coupling factor value of zero, i.e. zero mutual inductance, is required when the steady-state duty ratio operating point approaches either zero or one.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.195-196
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• 2015

This paper investigates the design of coupled inductor for minimum inductor current ripple in rapid traction battery charger systems. Based on the general circuit model of coupled inductor together with the operating principles of dc-dc converter, the relationship between the ripple size of inductor current and the coupling factor is derived under the different duty ratio. The optimal coupling factor which corresponds to a minimum inductor ripple current becomes -0.5, i.e. a complete inverse coupling without leakage inductance, as the steady-state duty ratio operating point approaches 1/3 or 2/3. In an opposite manner, the optimal coupling factor value of zero, i.e. zero mutual inductance, is required when the steady-state duty ratio operating point approaches either zero or one. Coupled inductors having optimal coupling factor can minimize the ripple current of inductor and battery current resulting in a reliable and efficient operation of battery chargers.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1299-1305
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• 2017

In this paper, we consider a beamforming game between the transmitters in a two-user multiple-input single-output interference channel using limited feedback and investigate how each transmitter is able to find a modified strategy from the quantized channel state information (CSI). In the beamforming game, each of the transmitters (i.e., a player) tries to maximize the achievable rate (i.e., a payoff function) via a proper beamforming strategy. In our case, each transmitter's beamforming strategy is represented by a linear combining factor between the maximum ratio transmission (MRT) and the zero forcing (ZF) beamforming vectors, which is the Pareto optimal achieving strategy. With the quantized CSI, the transmitters' strategies may not be valid because of the quantization errors. We propose a modified solution, which takes into account the effects of the quantization errors.

• Biomolecules & Therapeutics
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• v.5 no.1
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• pp.59-66
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• 1997

This study was done to determine that vitamins I and C are synergistic in protecting liver cells during hepatic ischemia and repefusion. Rats treated with vitamins I and C were subjected to 60 min of hepatic ischemia and to 1 and 5 hr of reperfusion thereafter. Serum aminotransferase level and microsomal lipid peroxidation were markedly increased by ischemia/reperfusion. These increases were significantly attenuated by vitamins E, C or its combination. Hepatic wet weight-to-dry weight ratio was increased in ischemic group, but this increase was prevented by combination of vitamin I and C. Bile flow and cholate output were markedly decreased by ischemia/reperfusion and vitamin C alone and combination of vitamin I and C restored their secretion. Cytochrome P-450 content and aminopyrine N-demethylase activity were decreased by ischemia/ reperfusion and restored by vitamin C and combination of vitamin I and C to the level of sham-operated rat. Aniline p-hydroxylase activity was increased by ischemia/reperfusion and this increase was prevented by vitamin E. Our findings suggest that ischemia/reperfusion diminishes hepatic secretory and microsomal functions by increasing lipid peroxidation and vitamins I and C synergistically ameliorates these changes.

• Speech Sciences
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• v.7 no.3
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• pp.11-19
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• 2000

The present electropalatographic study reports the production of the allophones. i.e., [l] and [r], of Korean tap /r/ and their coarticulatory characteristics in /$C{\'{a}}r#g$/ and /$C{\'{a}}r#i$/ sequences. The finding that tap /r/ involves a complete oral closure with less lingual contact, i.e., apico-frontalveolar coupling. than lateralized /r/ which involves apico-bladealveolar coupling and tongue dorsum lowering for adequate airflow through either side and/or both of the tongue body suggests that the two allophones of the tap /r/ have different lingual gestures. Moreover. in comparison with the tap. the lateral exerts longer lingual contacts. The mean ratio between them is 3.7. In the sequences /Car#g/. the two adjacent antagonistic segments (i.e., /r/ and /g/) show mutual coarticulation effects taking on features of adjacent segment. but either of them is precisely constrained without blocking the formation of involved major lingual gestures for the other segment. In sequences /Car#i/ occurs anticipatory V-to-C coarticulation but not vocalic carryover effects. In both sequences. the allophones reveal insignificant wordinitial consonantal carryover coarticulatory effects and insignificant speaker-specific lingual contacts.