• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.31.3-32
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• 2016

We present the radial variations of the scale heights and the vertical velocity dispersions in a sample of nearby edge-on galaxies using BIMA/CARMA $^{12}CO$ ($J=1{\rightarrow}0$), VLA/EVLA HI, and Spitzer $3.6{\mu}m$ data. Both the disk thicknesses and the velocity dispersions of gas and stars vary with radius, contrary to assumptions of previous studies. We investigate how the interstellar gas pressure and the gravitational instability parameter differ from values derived assuming constant velocity dispersions and scale heights. Using the measurement of the disk thicknesses and the derived radial profiles of gas and stars, we estimate the corresponding volume densities. The gravitational instability parameter Q follows a fairly uniform profile with radius and is ${\geq}1$ across the star-forming disk. The star formation law has a slope that is significantly different from those found in more face-on galaxy studies. The midplane gas pressure appears to roughly hold a power-law correlation with the midplane volume density ratio (${\rho}_{H2}/{\rho}_{HI}$).

• The Journal of Asian Finance, Economics and Business
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• v.9 no.6
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• pp.127-137
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• 2022

This paper aims to investigate the impact of corporate governance on the quality of integrated reporting. Corporate governance includes internal (board size, board independence, and board diversity) and external (audit quality and enforcement) governance factors. This paper develops an index to capture the quality of integrated reporting by employing the completeness of information required by the International Integrated Reporting Council (IIRC). For an international sample, the paper manually collects 160 integrated reports along with internal and external governance factors and employs multivariate analyses to examine the association between these governance factors and the quality of integrated reporting. The empirical results suggest that firms with a larger board of directors, a larger proportion of female members on board, and located in countries with enforcement for integrated reporting requirements have a higher quality of integrated reporting. Our conclusions still hold after accounting for several conditions, including the industry-fixed and year-fixed effects. Together, these results suggest that both internal and external governance factors are important determinants for the quality of integrating reporting. These results have several theoretical and practical implications as they fulfill the absence of relevant studies on addressing the impact of internal and external corporate governance factors on the quality of integrated reporting.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.9
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• pp.181-189
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• 2022

The current study examines the nexus between the capital structure (debt-equity) and firm value (Tobin's Q) by including profitability (alternatively Return on Assets (ROA) and Return on Equity (ROE)) as a moderator in the companies of Saudi Arabia. The study sample consists of 102 companies listed on Tadawul (the Saudi Arabian stock exchange) from different sectors of Saudi Arabia during the period 2013 to 2020. The study estimates pooled regression, panel regression with fixed and random effects, and dynamic panel regression models to report the results. The study results report that there is a negative and significant association between capital structure and firm value in model 1, while in models 2 and 3 there is a more negative and significant impact between the two study variables compared to model 1 after the inclusion of interaction variable, i.e. profitability in terms of ROA and ROE. The comparative result shows that the companies of Saudi Arabia hold more debt in their capital structure mix, hence evidencing a decrease in the firm value. The reported results also show that models 2 and 3 are better in explaining the impact of capital structure on firm value due to the interaction of profitability compared to model 1.

• The Research Journal of the Costume Culture
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• v.20 no.2
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• pp.272-285
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• 2012

The purpose of the study is to examine the role of consumer perceptions of websites' entertainment and informativeness in developing their attitudes (attitude toward the retailer and attitude confidence toward the product) in the context of apparel e-tailing. A structural equation model was developed for an empirical test based on the literature on uses-and-gratifications and attitude confidence. A sample of 119 consumers who live in the United States participated in the online survey. The results generally supported the proposed model. Specifically, the analyses revealed that consumers' purchase intention toward the displayed product is positively influenced by their attitudes toward the retailer and by their confidence in their attitudes toward the product. Interestingly, only one of the two cognitive antecedents, perceived entertainment, has a positive impact on consumers' attitude toward the retailer. Perceived informativeness, however, had a positive impact on attitude confidence. These findings suggest that consumers who have high perception of an e-tail website's entertainment are more likely to exhibit favorable attitudes toward the e-tailer, while consumers who have high perception of an e-tail website's informativeness are more likely to hold strong confidence in their attitudes toward the product displayed on the website. Both consumer attitudes toward the e-tailer and their attitude confidence lead to their purchase intentions.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.374-376
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• 2001

FACTS technology is developed into the sophisticated system technology which combines conventional power system technology with power electronics, micro-process control, and information technology. Its objectives are achieving enhancement of the power system flexibility and maximum utilization of the power transfer capability through improvements of the system reliability, controllability, and efficiency[1]. As a series and shunt compensator, UPFC consists of two inverters with common dc link capacitor bank. It controls the magnitude of shunt bus voltage and real and reactive power flow of transmission line[2]. In this paper, we present the design and control algorithm of UPFC simulator for KERI simulator. As a control algorithm is implemented by digital controller, we consider sample-and-hold of signals In this simulation, we use EMTDC/PSCAD V3.0 software which can simulate instantaneous voltage and current.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.255-258
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• 2004

The SAR(Solar Array Regulator) of KOMPSAT(Korea Multi Purpose SATellite)-1, 2 regulates a photovoltaic power according to the duty ratio commands of the ECU. But the ECU has so many other jobs that it can not calculate the solar array condition immediately. It means the SAR cannot always generate the maximum power of a photovoltaic. Nowadays, the commercial photovoltaic systems are using a controller operated by digital processing. But the usage for satellite is not adaptable. It is not easy to find the processor of the space grade and the price is expensive. So in this paper, the simple analog MPPT(Maximum Power Point Tracking) algorithm is proposed for the small satellite in LEO. This algorithm does not need any calculation of power by multiplication of voltage and current md a measurement of the solar array temperature. It is consist of only two sample and hold circuits, two comparators, a flip-flop, and an integrator. The proposed MPPT algorithm is verified by the simulation and experimental.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.12
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• pp.77-84
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• 1998

A voltage controlled chaotic circuit has been designed in integrated circuit and fabricated by using 0.8$\mu\textrm{m}$ single poly CMOS technology. The fabricated chaotic circuit consist of sample and hold circuits, op-amps, nonlinear function generator and two phase clock generator. The test results of the chaotic circuit show that periodic state, quasi-periodic state and chaotic state can be obtained according to the input control voltage with the ${\pm}$2.5V power supply and clock rate of 20kHz. In addition, two dimensional chaotic patterns have been observed by connecting this circuit in parallel or series

• The Korean Journal of Applied Statistics
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• v.23 no.2
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• pp.325-333
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• 2010

Protection against disclosure of survey respondents' identifiable and/or sensitive information is a prerequisite for statistical agencies that release microdata files from their sample surveys. Coarsening is one of popular methods for protecting the confidentiality of the data. Grouped data can be released in the form of microdata or tabular data. Instead of releasing the data in a tabular form only, having microdata available to the public with interval codes with their representative values greatly enhances the utility of the data. It allows the researchers to compute covariance between the variables and build statistical models or to run a variety of statistical tests on the data. It may be conjectured that the variance of the interval data is lower that of the ungrouped data in the sense that the coarsened data do not have the within interval variance. This conjecture will be investigated using the uniform and triangular distributions. Traditionally, midpoint is used to represent all the values in an interval. This approach implicitly assumes that the data is uniformly distributed within each interval. However, this assumption may not hold, especially in the last interval of the economic data. In this paper, we will use three distributional assumptions - uniform, Pareto and lognormal distribution - in the last interval and use either midpoint or median for other intervals for wage and food costs of the Statistics Korea's 2006 Household Income and Expenditure Survey(HIES) data and compare these approaches in terms of the first two moments.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.24 no.1
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• pp.1-6
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• 1988

For the purpose of making the detection range of fish detection system more longer and computerizing the system a parametric sound source, a timer and a digitizing circuit for the Apple II computer have been studied. The parametric sound of 5 KHz generated by passing AND gate two signals from carrier signal generator of 200KHz with modulator of 5KHz. This parametric acoustic source of 5KHz difference frequency had more higher directional resolution of 10 degrees than single frequency sound of 200KHz. Peripheral interface adaptor MC 6821 was adopted for interfacing to the Apple II personal computer. The timer consisted of six decade binary coded decimal counters (74 LS 190), and the digitizing circuit consisted of a sample and hold (LF 398) and an A/D converter(ADC 0808). The timer with 10KHz clock pulse had the measuring time from 0.1msec to 100sec. This time measuring range was satisfactory for the aim of the fish finding acoustic system.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.8
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• pp.137-148
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• 2021

The study investigates the existence of an optimal level of cash and the firm characteristics influencing the decision to hold cash, and the adjusting speed of the cash holdings to the target level. It highlights the heterogeneity of cash adjustment speed in the Vietnam market. The research employs the 417 samples of Vietnamese non - financial listed firms in the period of 2010 to 2019. The study uses the Pool OLS model, Fixed effect model (FEM), Random effect model (REM), and GMM model. According to the research findings, there is an optimal amount of cash at which the firm's value is maximized in Vietnamese listed firms, and the majority of the firms in the sample retain cash over the target level. Furthermore, the study demonstrates that firms actively modify their cash holdings to the optimal level with an adjustment speed of less than one owing to adjustment cost constraints. This speed varies between groupings of enterprises with different characteristics, underlining the heterogeneity of the adjustment speed even more. Small deviation firms adjust more rapidly than large deviation firms. Large free cash flow (FCF) firms adjust more readily than small FCF firms, and fiscal deficit firms modify more rapidly than firms with a financial surplus.