• Journal of Industrial Convergence
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• v.2 no.1
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• pp.23-46
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• 2004

Tax exhaustion effect hypothesis says that firms with low expected marginal tax rates on their interest deductions employ less debt in their capital structure. We use logit analysis to study how financing decision is related to tax after controlling non tax effects. We treat non debt tax shields as proxy of marginal corporate tax rates which affect the probability of using the deductibility of debt tax shields and empirically test the tax effect on financing decision in Korea. In conclusion, we provide evidence that debt financing is positively related to tax in the former sub-period. This results partially support for tax exhaustion effect hypothesis and low tax rate firms have lower debt levels than high tax rate firms.

• International journal of advanced smart convergence
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• v.12 no.3
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• pp.19-24
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• 2023

Recently, fifth generation (5G) networks are being deployed in phases all over the world, the paradigm has shifted to developing the next generation wireless technologies, which have grown exponentially in last few decades, wireless networks are promising for the demand to enormous connections. Non-orthogonal multiple access (NOMA) and intelligent reflecting surface (IRS) are considered as the key technoloies for next-generation beyond 5G (B5G) and sixth generation (6G) networks, in which IRS can play an important advance in the wireless propagation environment, and NOMA can effectively increase massive connectivity to improve user fairness. In this paper, we analyze a performance on the strongest channel user in terms of achievable data rates numerically. Then, with the achievable data rates, the signal-to-noise ratio (SNR) gain is calculated for the IRS-NOMA network over the conventional NOMA network. As a consequence, IRS-NOMA schemes have been considered as some key technologies.

• The Journal of Economics, Marketing and Management
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• v.5 no.4
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• pp.1-9
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• 2017

This current study aims to investigate the reason for the low birth rate and increasing aging populations. It aims to offer potential countermeasures and possible solutions that might alleviate the decreasing birth rate and exponentially increasing aging populations. The present research has sought out to uncover the origin of the low birth rates and increasing aging populations by compiling various past studies and statistics in South Korea. It includes additional support from the government for working career women in easing their burden for raising a child and allocating the appropriate funds for the increasing elderly populations. The decreasing birth rate can be contributed as a side effect of the past policies passed in South Korea and in turn created an increase in the aging populations. Policies to tackle this current issue needs to be further investigated and employed for the future of the economic and sociological stability of the society. Consistent efforts need to be made to dispel the continuing decrease for birth rates and alarmingly increasing aging populations. Policies and redistribution of government funds are some of the many things that need to be revised.

• Journal of the Korea Convergence Society
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• v.7 no.2
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• pp.43-52
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• 2016

The purpose of this study was to suggest the effective squat exercise position to strengthening vastus medialis oblique, and vastus lateralis in quadriceps. Subjects were twenty patients with patellofemoral pain syndrome (PFPS) volunteered to participate in this study. All subjects were applied to static squat convergence exercise with knee flexed $45^{\circ}$, $60^{\circ}$, and $90^{\circ}$ for 30 seconds total 5 times. Measurement variables were maximal voluntary isometric contraction (MVIC) of the quadriceps, Q angle and length of thigh. Those were measured before and after the squat exercise on knee joint angle, change rate of which were used for statistical analysis. As a result, squat exercise with knee flexed $90^{\circ}$ increase significantly among knee joint angle in the MVIC change rates of quadriceps (p<.05), however the rates of Q-angle and length change of thigh showed no significant difference. Therefore, this findings suggest that squat exercise with knee flexed $90^{\circ}$ strengthen quadriceps effectively in patients with PFPS.

• Microbiology and Biotechnology Letters
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• v.50 no.4
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• pp.533-547
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• 2022

This study investigated the hair growth effect of Schisandra chinensis extract (TS-SC) and TS-SC fermented by Lactobacillus plantarum (TS-SCLF) on human dermal papilla cells (hDPCs). The production of vascular endothelial growth factor (VEGF), insulin-like growth factor 1 (IGF-1), keratinocyte growth factor/fibroblast growth factor 7 (KGF/FGF-7) and hepatocyte growth factor (HGF), transforming growth factor beta 1 (TGF-β1) were examined. The secretion rates of VEGF and KGF/FGF-7 were high in TS-SC, and the secretion rates of IGF-1 and HGF were high in TS-SCLF. TGF-β1 was inhibited in a concentration-dependent manner in all samples. Gene expression of VEGF, IGF-1, KGF, HGF and alkaline phosphatase, relevant to hair growth, were examined. The data revealed that TS-SC and TS-SCLF successfully promoted hair growth in hDPCs. The IGF-1 gene was expressed in a dose-dependent manner in TS-SCLF. These results indicate that TS-SC and TS-SCLF fermented extract effectively promoted hair growth and gene expression relevant to hair growth in hDPCs. Used in clinical trials the test substance 'CMK-LPF01' showed a statistically significant increase in the number of hairs at 8 weeks, 16 weeks, and 24 weeks compared to before product use, and a change in hair growth, a secondary efficacy evaluation variable. Through additional research in the future, it is expected that "CMK-LPF01" can be developed as a functional material that can help alleviate symptoms of hair loss.

• Journal of Biomedical Engineering Research
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• v.43 no.4
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• pp.271-279
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• 2022

Functional cosmetics containing various ingredients that improve skin health are currently being developed. In addition, technologies that help increase the absorption rate of such cosmetics have recently gained significant attention. Sonophoresis is a method to increase the transdermal absorption of cosmetics using ultrasound. A skin-mimicking phantom was fabricated using polydimethylsiloxane, Strat-M^TM membrane, and thermochromic pigments. Gel-type cosmetics used in skin mask packs and epidermal-growth-factor-based nano-cosmetics were tested for their absorption rates at ultrasound frequencies of 1, 3, and 10 MHz in the single frequency mode, and 1/3 and 3/10 MHz in the dual frequency mode. The gel-type cosmetics and epidermal-grow-factor-based nano-cosmetics showed the highest absorption rate at 3/10MHz dual frequency. The size of the cosmetic particles decreased by 5-9 %. Furthermore, the temperature rise caused by ultrasound could be visually recognized by the thermochromic pigment in the phantom turning white. We presented a skin-mimicking phantom. The device can be customized according to the size of the ultrasound probe and has the advantage of quantitatively evaluating the transdermal permeability of cosmetics at a low cost. The development of the skin-mimicking phantom will be useful for determining the suitable conditions required to increase the absorption rate of cosmetics using ultrasound.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.8
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• pp.745-757
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• 1991

In this paper, the theoretical convergence property of the individual tap LMS algorithm for equaliz action if analyzed, and the pefomances over seeral multipath time vaing mobile radio channels are investigaed. The individual tap adjusting method of the tapped-elay line equalizer using LMS algorithm is proved to have Wiener optimum solution. It has more rapid convergence speed and lowe bit error rates than conventional Tdl LMS and gradient lattice equlizer in time invariant or time variant multipath channels.

• Journal of the Korean Society of Industry Convergence
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• v.3 no.1
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• pp.69-75
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• 2000

Multichip packages are comprised of dissimilar materials which expand at different rates on heating. The differential expansion must be accommodated by the various structural elements of the package. A types of heat exposures occur operation cycles. This study presents a finite element analysis simulation of flip-chip among multichip. The effects of geometries and material properties on the reliability were estimated during the analysis of temperature and thermal stress of flip-chip. From the results, it could be obtained that the more significant parameters to the reliability of flip-chip arc chip power cycle, heat convection and height of solder bump.

• Journal of the Korean Mathematical Society
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• v.48 no.2
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• pp.311-327
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• 2011

This paper is devoted to simplified Tikhonov regularization for two kinds of parabolic equations, i.e., a sideways parabolic equation, and a two-dimensional inverse heat conduction problem. The measured data are assumed to be known approximately. We concentrate on the convergence rates of the simplified Tikhonov approximation of u(x, t) and its derivative $u_x$(x, t) of sideways parabolic equations at 0 $\leq$ x < 1, and that of two-dimensional inverse heat conduction problem at 0 < x $\leq$ 1, respectively.

• Structural Engineering and Mechanics
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• v.26 no.2
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• pp.191-210
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• 2007

The three different approaches (reformulations) of evolution strategies (ESs) have been proposed in the literature as extensions of the technique for solving discrete problems. This study implements an extensive research on application, evaluation and comparison of them in discrete optimum design of steel frames. A unified formulation is first developed to explain these approaches, so that differences and similarities between their inherent search mechanisms can clearly be identified. Two examples from practical design of steel frames are studied next to measure their performances in locating the optimum. Extensive numerical experimentations are performed in both examples to facilitate a statistical analysis of their convergence characteristics. The results obtained are presented in the histograms demonstrating the distribution of the best designs located by each approach. In addition, an average improvement of the best design during the course of evolution is plotted in each case to compare their relative convergence rates.