• The Journal of Asian Finance, Economics and Business
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• v.7 no.6
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• pp.379-385
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• 2020

The effect of research and development (R&D) expenditure on firm output is an interesting topic, but hardly explored in developing countries due to the unavailability of data. This study investigates this topic in the context of Vietnam by utilizing a novel dataset of 343 firms listed on the Vietnam Stock Exchange in the 2010-2018 period. The effect of R&D expenditure is examined under the production function framework. In order to obtain the robustness of the quantitative results, we estimate the production function with two coherent techniques including the OLS and 2-SLS. An instrumental variable regression technique is adopted to avoid the endogeneity problem between R&D expenditure and other variables. In our empirical analysis, we find that R&D expenditure has a positive and significant impact on output growth. The finding is robust in both OLS and 2-SLS frameworks. Besides, the output elasticity to R&D expenditure of our result is much higher than the estimated elasticity of other countries. The results imply that a 1% increase in R&D expenditure in Vietnam will help to expand the output more than a 1% increase in R&D investment in other countries. The findings from our paper provide important implications for firm managers, investors, and policymakers in Vietnam.

• Asian Journal of Business Environment
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• v.9 no.3
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• pp.5-9
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• 2019

Purpose - This paper examines whether fiscal and monetary expansion would affect output in Australia. Research design, data, and methodology - An extended IS-LM model which describes the equilibrium in the goods market and the money market is applied. The real effective exchange rate and the real stock price are included in order to determine whether there may be any substitution or wealth effect. The sample consists of Annual data ranging from 1990 to 2018. The GARCH process is used in empirical work to correct for potential autoregressive conditional heteroscedasticity. Results - Expansionary fiscal policy reduces output; whereas, expansionary monetary policy raises output. In addition, real appreciation of the Australian dollar, a lower U.S. interest rate, a higher real stock price or a lower expected inflation would increase output. The finding that expansionary fiscal policy has a negative impact on real GDP suggests that the negative crowding-out effect on private spending dominates the positive impact. Conclusions - Fiscal prudence needs to be pursued. Real depreciation of the Australian dollar hurts output. Monetary tightening in the U.S. generates a negative effect on Australia's output. A healthy stock market is conducive to economic growth as higher stock prices tend to result in the wealth and other positive effects, increasing consumption and business spending.

• Journal of Power Electronics
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• v.17 no.4
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• pp.1109-1116
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• 2017

Wireless power transfer (WPT) technology has the advantages of intelligence and facilitation. This paper designs a WPT system applied to battery charging and provides a strategy which switches from the constant current (CC) charging mode to constant voltage (CV) charging mode. The LCL-LCL topology is used to realize the CC output, while the LCL-S (series compensation) topology is used to realize the CV output. The main factor affecting the output characteristics is extracted by analyzing the two topologies above. Based on the main factor, this paper puts forward a modified way to design the system. In addition, on-line monitors for the battery and switches are placed at receiving side, which avoids the need for introducing an information interaction module into the system. Therefore, the complexity of the controlling system is reduced. Finally, simulation and experimental analyses are carried out to verify the correctness of the compound topologies.

• Transactions of Materials Processing
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• v.30 no.6
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• pp.284-290
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• 2021

Manufacturing using a 3D printer has recently increased in many fields and the material extrusion method, which is a lamination method, is commonly used. Since it uses a plastic material, the strength of the output of 3D printing is lower than that of steel material. For this reason, research on improving the mechanical properties of the output of 3D printing is continuously being conducted. In this study, tensile strength was compared with changes in the material type (PLA+, ABS) and density (60, 80, and 100%), layer height (0.1, 0.2, and 0.3 mm), layer direction (transverse and lengthwise), and fill pattern (zigzag, honeycomb, and concentric) among 3D printing output conditions. Tensile tests according to 3D printing output conditions were performed using a Universal Testing Machine. The results showed that tensile strength ranged from 21.10 MPa to 43.65 MPa according to the 3D printing output conditions.

• Journal of Korea Technology Innovation Society
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• v.5 no.2
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• pp.189-211
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• 2002

The research shows how the technological change of 'Information and Communication Technology' (ICT) is accompanied with the usage change. It aims to provide a better conceptualization with empirical findings about the fact that the technological development of ICT is a convergence process of ICT factors with the usage of ICT moving from a limited coverage toward a general-purpose. The research adapts a descriptive methodology on a historical matter and demonstrates how it can be conducted through analytical description of Input-Output tables (I/O) the over periods. The case is about the UK with sequential I/O during 1970s- 90s.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.518-521
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• 1989

Recently, PWM cycloconverters that are frequency conversion system have been studied for eliminating do links of conventional converter and inverter systems. A new real-time method for generating PWM patterns is proposed in this paper. This method realizes sinusoidal input and output currents, controllable input displacement factor regardless of load power factor, and maximum output voltage range. Finally, feasibility of the proposed method is confirmed by simulation and experiments.

• Journal of the Korean Society for information Management
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• v.32 no.3
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• pp.317-340
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• 2015

This study clarified the knowledge structure of international collaboration in psychiatry based on analyzing networks in order to construct cooperation networks for international collaboration in psychiatry in South Korea. The result of analysis of knowledge structure at a state-level is as follows. First, this study found that the rate of collaboration for five years is high as 89.97%. Moreover, this study investigated the change of rate of collaboration and international collaboration according to the passage of time, and ascertained that while the rate of international collaboration has increased, Second, this study examined the trend of research on collaboration between Asian countries, and found that collaboration between Asian countries is on a low level. Third, the country (or group) that the number of papers of international collaboration and the value of centrality are the highest is EU-28. The result of analysis of knowledge structure at a research output-level is as follows. this study analyzed the correlation of centrality with research output, and found that positive correlation exists in the three indicators of centrality, and a country with high centrality has good research output.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.95-99
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• 2005

This paper presents a general proposal to design and calculate the performance of a tubular permanent magnet linear generator treated here on the basis of the Finite Element Method. Optimizing the linear generator dimensions reduces the cogging force, which occurs due to the interaction between stator teeth and the permanent magnets. The generated AC voltage is analyzed and evaluated for both no load and load cases to take the armature reaction effects on the air gap flux density. A repetitive routine is followed to calculate the output AC voltage from the change of flux and the speed of the single-phase linear generator. The AC output voltage is calculated for different resistive loads, and hence, the linear generator load characteristic is obtained. The designed linear generator is capable to generate an output power of 5.3kW with AC output voltage of 222V with an efficiency of 96.8% at full load of 23.8A. The full load current is chosen based on the thermal properties of the coil wire insulations.

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.2
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• pp.65-73
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• 2013

In the simulation output analysis, bootstrap method is an applicable resampling technique to insufficient data which are not significant statistically. The moving block bootstrap, the stationary bootstrap, and the threshold bootstrap are typical bootstrap methods to be used for autocorrelated time series data. They are nonparametric methods for stationary time series data, which correctly describe the original data. In the simulation output analysis, however, we may not use them because of the non-stationarity in the data set caused by the trend such as increasing or decreasing. In these cases, we can get rid of the trend by differencing the data, which guarantees the stationarity. We can get the bootstrapped data from the differenced stationary data. Taking a reverse transform to the bootstrapped data, finally, we get the pseudo-samples for the original data. In this paper, we introduce the applicability of bootstrap methods to the time series data having trend, and then verify it through the statistical analyses.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.173-174
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• 2016

This paper proposes a comparison of Voltage Oriented Control (VOC) and Direct Power Control (DPC) under command mode transition for PMSG Wind Turbines (WT). Based on a neutral point clamped three level back to back type Voltage Source Converter (VSC), proposed control scheme automatically control the generated output power to satisfy a grid requirement from the hierarchical wind farm controller. Automatic command mode transition based on the dc-link voltage error provides a command mode changing between grid command and MPPT mode. It is confirmed through PLECS simulations in Matlab. Simulation result shows that proposed control scheme of VOC and DPC achieves a much shorter transient time of generated output power than the conventional control scheme of MPPT with optimal torque control and VOC under a step response. The proposed control scheme makes it possible to provide a good dynamic performance for PMSG wind turbines in order to generate a high quality output power.