• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.12
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• pp.1051-1057
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• 2000

A traveling-wave CPW(coplanar waveguide) electrode with abruptly broken input/output-taper for LiNbO$_3$optical modulator was designed and fabricated. The electrical characteristics of traveling-wave electrode on z-cut LiNbO$_3$crystal with SiO$_2$buffer layers were measured by network analyzer. To confirm the possibility of the electro-optic modulator electrode, detailed calculations of the impedance, microwave effective index and attenuation constants are presented as a function of the microwave electrode thickness, but the buffer layer thickness is fixed as 1${\mu}{\textrm}{m}$. These characteristics are discussed from the viewpoint of the device optimization and are expected to be design guides for the LiNbO$_3$modulator’s electrodes.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.118-127
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• 2005

A spatial 3 degrees-of-freedom mechanism employing Stewart Platform structure is proposed: the mechanism maintains the 3- RRPS structure of Stewart Platform but has an additional passive PRR serial sub-chain at the center area of the mechanism in order to constrain the output motion of the mechanism within the output motion space of the added PRR serial subchain. The forward and reverse position analyses of the mechanism are performed. Then the mechanism having both the forward and the reverse closed-form solutions is suggested and its closed form solutions are derived. It is confirmed, through the kinematic analysis of those two proposed mechanisms via kinematic isotropic index, that both the proposed mechanisms have fairly good kinematic characteristics compared to the existing spatial 3-DOF mechanisms in literature.

• Journal of Information Science Theory and Practice
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• v.3 no.4
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• pp.35-48
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• 2015

The aim of this study is to compare country output and citation impact as well as to assess the level of interdisciplinarity in the field of tribology research during the period 1998-2012, based on the SCOPUS database. Macro-level scientometric indicators such as growth rate, share of international collaborative papers, citation per paper, share of un-cited papers, and publication efficiency index were employed. Further, the Simpson Index of Diversity was used to measure the level of interdisciplinarity. The performance of top countries contributing more than 1000 papers during the study period was discussed. Contributions and share of continents and countries by income groups were examined. Further research contributions and citation impact of selected country groups were analyzed. This study reveals that high levels of interdisciplinarity exist in tribology research. Asia outperforms the other world regions and China contributes most of the papers (25%), while the United States receives most of the citations (22%).

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.2
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• pp.135-141
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• 2006

In this paper, LC output filters are designed to reduce output harmonics and harmonic analysis are peformed. Generally, multilevel inverters are used in high power application and operates with low switching frequency, which, in turn, generates large output harmonics. Output filters we used to reduce output harmonics. The design approach to reduce output harmonics of the 31eve1 multilevel inverter is discussed and DSP(TMS320C31) is used for the digital control of the system. The design example is given. The designed system is verified by simulation and experiment.

• Journal of Chest Surgery
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• v.23 no.1
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• pp.32-40
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• 1990

Surgical correction of congenital cardiac defects in infants and children with an elevated pulmonary arterial pressure or pulmonary vascular resistance carries a significant early postoperative mortality. And accurate assessments of cardiac output is critically important in these patients. From April 1988 through September 1989, serial measurements of cardiac index, ratio of pulmonary-systemic systolic pressure, ratio of pulmonary-systemic resistance, central venous pressure, left atrial pressure, and urine output during the first 48 hours after the cardiac operation were made in 30 congenital cardiac defects associated with pulmonary hypertension. Cardiac index showed significant increase only after 24 hour postoperatively and this low cardiac performance in the early postoperative period should be considered when postoperative management is being planned in the risky patients. There were no variables which showed any significant correlation with cardiac index. In 12 cases[40%], pulmonary hypertensive crisis developed during the 48 hours postoperatively, and they were treated with full sedation, hyperventilation with 100 % 0y and pulmonary vasodilator infusion. In all patient with preoperative pulmonary hypertension, surgical placement of a pulmonary artery catheter is desirable to allow prompt diagnosis of pulmonary hypertensive crisis and to monitor subsequent therapy.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.11
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• pp.1195-1202
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• 2004

The international competition in refrigerator markets has continuously required the research for sound quality of a refrigerator to improve the quality of a life. In this paper, A new method for evaluation of the sound quality of a refrigerator is developed based on human sensibility engineering by using ANN(artificial neural network). In this paper, the loudness and the sharpness of the refrigerator's signals was used for the input value in ANN's training process because the loudness and the sharpness has a good correlation between the output of the ANN and the target of the individual evaluation In the training process. Two input factor was used repeatedly in the training process to get more optimum weighting value. And then finally we developed the sound quality index of a refrigerator. The developed sound quality index was confirmed by the 96.5 % of correlation between the output of the ANN and the real evaluation. It will be applied to evaluate the sound quality of a refrigerator in the industry.

• Journal of Convergence Society for SMB
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• v.3 no.2
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• pp.19-25
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• 2013

Decision procedure was done with the evaluation of multi-criterion analysis. Importance of each criterion was considered through heuristically method, specially it was based on the heuristic least mean square algorithm. To consider coalition evaluation, it was carried out by calculation of Shapley index and Interaction value. The model output is also analyzed with the help of those two indexes, and the procedure was also displayed with details. Finally, the differences between the model output and the desired results are evaluated thoroughly, several problems are raised at the end of the example which require for further studying.

• East Asian Journal of Business Economics (EAJBE)
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• v.9 no.2
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• pp.1-10
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• 2021

Purpose - The purpose of this study is to measure the efficiency of social security expenditure in 31 provinces, cities and autonomous regions in China and proposes corresponding improvement plans. Research design, data, and methodology - The data were obtained from the statistical yearbook of each province. The BCC and CCR models of DEA model and Malmquist index are used to analyze the efficiency, and the input-output index is expanded. Result - The results show that the social security performance of the Chinese government has improved on the whole despite the unbalanced development in different regions. Each region should look for strategies to improve the efficiency of social security according to its own problems. The study suggests that provinces affected by TCI should improve their internal environment, such as raising social security fund structure and strengthening fund supervision, to improve efficiency. Areas affected by TECI need to be more responsive to policy, socio-economic and technological development. Conclusion - The research conclusion can provide reference for Chinese provinces to improve the efficiency of social security expenditure in the future. This study is not comprehensive enough in the selection of input-output indicators, which can be further expanded in the future.

• ETRI Journal
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• v.45 no.4
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• pp.636-649
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• 2023

Renewable energy generation cannot be consistently predicted or controlled. Therefore, it is currently not widely used in the electricity market, which requires dependable production. In this study, reliability- and variance-based controls of energy storage strategies are proposed to utilize renewable energy as a steady contributor to the electricity market. For reliability-based control, photovoltaic (PV) generation is assumed to be registered in the power generation plan. PV generation yields a reliable output using energy storage units to compensate for PV prediction errors. We also propose a runtime state-ofcharge management method for sustainable operations. With variance-based controls, changes in rapid power generation are limited through ramp rate control. This study introduces new reliability and variance indices as indicators for evaluating these strategies. The reliability index quantifies the degree to which the actual generation realizes the plan, and the variance index quantifies the degree of power change. The two strategies are verified based on simulations and experiments. The reliability index improved by 3.1 times on average over 21 days at a real power plant.

• Journal of the Korean Society for information Management
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• v.27 no.1
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• pp.249-267
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• 2010

The h-index is a new tool for measuring research outputs based on citation and many variants of h-index have been proposed to improve the weaknesses of h-index. The h-index and its variants can be applied to institutional evaluation in three different ways. We worked out 447 practical cases of professors from 10 business schools and examined h-index and its variants. And then we compared three evaluation methods of research institution based on the h-index and its variants.