• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.9
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• pp.446-451
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• 2006

The output voltage value of AC high voltage source has been usually measured by employing the high voltage divider of inductive or capacitive type. In the study, we have developed a new method for measuring the output voltage up to 60kV using parallel plates electrode and electric field sensor, which are constructed by home-made. Unlikely the conventional method using a high voltage divider, this developed method makes it possible to extend the range of output voltage from known low voltage measurement to high voltage measurement. From the linearity measured between electric field and applied voltage in the output voltage range of 1kV-30kV, the output voltage value up to 60kV can be obtained by the electric field measurement using the electric field sensor. The output voltage value obtained using the method is consistent with that obtained using high voltage divider within corresponding uncertainties.

• KDI Journal of Economic Policy
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• v.43 no.3
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• pp.33-53
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• 2021

The import content of exports (ICE) is defined as the amount of foreign input embodied in one unit of export, and it has been used as a measure of the degree of integration into the global production network. In this paper, we suggest an alternative measure based on the decomposition of gross output and imports into the contributions of final demand terms. This measure considers the manner in which a country manages its domestic production base (gross output) and utilizes the foreign sector (imports) simultaneously and can thus be regarded as a more comprehensive measure than ICE. Korea's input-output tables in 1970-2018 are used in this paper. These tables were rearranged according to the same 26-industry classification so that these measures can be computed with time-series continuity and so that the results can be interpreted clearly. The results obtained in this paper are based on extended time-series data and are expected to be reliable and robust. The suggested indicators were applied to these tables, and, based on the results we conclude that the overall importance of the global economy in Korea's economic strategy has risen and that the degree of Korea's integration into the global production network increased over the entire period. This paper also shows that ICE incorrectly measures the movement of the degree of integration into the global production network in some periods.

• International Journal of Control, Automation, and Systems
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• v.6 no.6
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• pp.939-947
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• 2008

The paper proposes a new formulation of the output feedback pole assignment problem. In this formulation, a unified approach is presented for solving the pole assignment problem with various additional objectives. These objectives include optimizing a variety of performance indices, and imposing constraints on the output feedback matrix structure, e.g. decentralized structure. Conditions for the existence of the output feedback are discussed. However, the thrust of the paper is on the development of a convergent pole assignment algorithm. It is shown that when exact pole assignment is not possible, the method can be used to place the poles close to the desired locations. Examples are provided to illustrate the method.

• Journal of the Korean Ceramic Society
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• v.51 no.5
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• pp.516-521
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• 2014

This paper describes the development of a new piezoelectric unimorph cantilever structure intended to improve electrical output power, compared to a conventional cantilever. The proposed structure employs a cylindrical bar attached to one side of a steel plate, which is a significant factor in forced vibration mode. The feasibility of the proposed methodology was assessed experimentally and theoretically. The influence of three different types of bar material (i.e., stainless steel, silicon rubber, and urethane), and bar position, on the output voltage were examined and compared with those without the bar. The optimal position and material for the bar were identified through experimental and theoretical analyses. It appears that the electrical output power of the proposed cantilever is about 40% higher than that of a conventional unimorph cantilever.

• Environmental Engineering Research
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• v.16 no.1
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• pp.19-27
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• 2011

This paper introduces an approach to identify the total energy consumption with subsequent $CO_2$ emissions, for both industrial and non-industrial sectors. Statistical data for 2005 were compiled in a national account system to construct an energy input-output table for investigating the influence between energy demand and supply activities. The methodological approach was applied to South Korea. Twelve types of energy and fifteen industrial and non-industrial sectors are formed as the compartments of the input-output table. The results provided quantitative details of the energy consumption and identified the significant contributions from each sector. An impact analysis on the $CO_2$ emissions for the demand side was also conducted for comparison with the supply side.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1221-1226
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• 2015

This paper proposes a multiple switch mode power supply (SMPS) system based on the wireless network which controls variable load. The system enables power supply of up to 600W using 200W SMPS as a unit module and provides a controlling function of output power based on variable load and a monitoring function based on wireless network. The controlling function for output power measures the variation of output power and facilitates efficient power supply by controlling output power based on the measured variation value. The monitoring function guarantees a stable power supply by observing the multiple SMPS system in real time via wireless network. The performance of the proposed system was examined by various experiments. In addition, it was verified through standardized test of Korea Testing Certification. The results were given and discussed.

• Smart Structures and Systems
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• v.7 no.1
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• pp.59-82
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• 2011

In this study, an output-only modal identification approach is proposed for decentralized wireless sensor nodes used for linear structural systems. The following approaches are implemented to achieve the objective. Firstly, an output-only modal identification method is selected for decentralized wireless sensor networks. Secondly, the effect of time-unsynchronization is assessed with respect to the accuracy of modal identification analysis. Time-unsynchronized signals are analytically examined to quantify uncertainties and their corresponding errors in modal identification results. Thirdly, a modified approach using complex mode shapes is proposed to reduce the unsynchronization-induced errors in modal identification. In the new way, complex mode shapes are extracted from unsynchronized signals to deal both with modal amplitudes and with phase angles. Finally, the feasibility of the proposed approach is evaluated from numerical and experimental tests by comparing with the performance of existing approach using real mode shapes.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.869-875
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• 2012

Because of the nature of wind, the output power of wind turbines fluctuates according to wind speed variation. Therefore, many countries have set up wind-turbine interconnection standards usually named as Grid-Code to regulate the output power of wind farms to improve power system reliability and power quality. This paper proposes three operation modes of wind farms such as maximum power point tracking (MPPT) mode, single wind turbine control mode and wind farm control mode to control the output power of wind turbines as well as overall wind farms. This paper also proposes an operation scheme of wind farm to alleviate power fluctuation of wind farm by choosing the appropriate control mode and coordinating multiple wind turbines in consideration of grid conditions. The performance of the proposed scheme is verified via simulation studies in PSCAD/EMTDC with doubly-fed induction generator (DFIG) based wind turbine models.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.498-500
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• 2012

According to the climatic characteristics of the wind power output is difficult to predict and a severe strain due to a change in output has been very influential in the grid. Jeju Hangwon wind farm, many of the wind generator is installed in a wide area because it is not have this device that artificially Smoothing is needed. In addition, By the requirements of the power company active power supply / control and improve power system reliability and energy storage during the peak demand for electricity using the energy stored in the power supply is needed. In this paper, Unit 12 in Jeju Hangwon demonstrated 0.5MW PCS and energy storage system associated with the wind through the stabilization of output and the leveling of output and test results will be introduced.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1232-1233
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• 2007

As the number of wind turbines installed increase, the power from wind energy starts to replace conventional generation units and its influence on power system can not be neglected. Because of the intermittent nature of wind resource, the output power of wind turbine fluctuates according to wind speed variation. In this point of view, it is necessary for wind turbines to be equipped with power regulation ability. The doubly fed induction generator (DFIG) is one of the main techniques used in variable speed wind turbines. This thesis focuses on the development of modified control scheme of DFIG to regulate output power. The proposed control scheme achieves active power output regulation so as to stabilize the power system.