• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.95-97
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• 1995

A superconducting current generator, or a superconducting rectifier(SCR) is used as a current source to energize a superconducting magnets in SMES, MRI. We selected a full-wave SCR among various SCR models and analyzed its operational characteristics by computer simulation. In process of pumping the current, the improvement of performance is dependent on how much bigger the open resistance of the switch is in comparison to load coil impedance when one of two switches become active. Faster transfer can he seen in resistive commutation mode by shortening the time elapsed for the resistance to arrive at certain level from zero state. Although recovery time for the switch has no direct effect on current pumping, optimal switch design is needed to increasing operational frequency.

• Journal of the Korean Society of Systems Engineering
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• v.4 no.2
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• pp.45-54
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• 2008

This paper describes an operational concept of the network based future airborne force power using a systems engineering approach. The battlefield is changing to new system of systems that command and control by the network based BM/C4ISR. Also, it is composed of various sensors and shooters in an single theater. Future threats may be characterized as unmanned moving bodies that the strategic effect is great such as UAVs, cruise missile and tactical ballistic missiles. New threats such as low altitude stealth cruise missile may also appear. The implementation of future airborne force power network systems against these future threats is required to complex and integrated approach based on systems engineering. This work developed the operational concepts of the future airborne network system, and then derived the requirements for performing missions effectively. In addition, the scheme of future airborne force power network systems is presented.

• Structural Engineering and Mechanics
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• v.37 no.6
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• pp.593-615
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• 2011

This study determines the water length effects on the modal behavior of a prototype arch dam using Operational and Analytical Modal Analyses. Achievement of this purpose involves construction of a prototype arch dam-reservoir-foundation model under laboratory conditions. In the model, reservoir length was taken to be as much as three times the dam height. To determine the experimental dynamic characteristics of the arch dam using Operational Modal Analysis, ambient vibration tests were implemented for empty reservoir and three different reservoir water lengths. In the ambient vibration tests, the dam was vibrated by natural excitations provided from small impact effects and the response signals were measured using sensitive accelerometers. Operational Modal Analysis software process signals collected from the ambient vibration tests, and Enhanced Frequency Domain Decomposition and Stochastic Subspace Identification techniques estimated modal parameters of the dams. To validate the experimental results, 3D finite element model of the prototype arch dam was modeled by ANSYS software for empty reservoir and three different reservoir water lengths, and dynamic characteristics of each model were determined analytically. At the end of the study, experimentally and analytically identified dynamic characteristics compared to each other. Also, changes on the natural frequencies along to water length are plotted as graphs. Results suggest that reservoir water complicates the modal behavior of the arch dam significantly.

• Journal of Korean Academy of Psychiatric and Mental Health Nursing
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• v.28 no.1
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• pp.50-63
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• 2019

Purpose: The objective of this study was to explore operational definitions and moderators of the resilience of adult children of alcoholics (ACOA) and its associated variables. Methods: This integrative review was conducted based on a literature review method suggested by Whittemore and Knafl. Databases including PubMed, CINAHL, PsycINFO, and RISS were searched using the combinations of search terms such as; 'adult children of alcoholics,' 'parental alcoholism,' 'resilience,' and 'children of alcoholics.' Results: Seventeen studies were selected for this review. Findings of integrative reviews reported operational definitions for the resilience of ACOA and moderators. The operational definition of ACOA's resilience is: (1) having no behavioral and emotional problem, (2) meeting social and developmental expectancies, (3) having the ability to cope with adversity, (4) having high self-concept, and (5) having a meaningful relationship. In addition, the varying environmental moderators include family communication, qualities of caring environment, parental communication, parentification, and social support. Several moderators were identified as positive effect, self-esteem, alcohol-specific coping style, locus of control, spirituality, the image of God, and dyadic cohesion in marital communication. Conclusion: Our study findings emphasize comprehensive understanding of diverse definition of resilience and moderators in developing nursing interventions to promote resilience in ACOA.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.1
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• pp.299-310
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• 2022

Environmental protection has been infused into the development of numerous fields by the Chinese government. The government's implementation of green development has also shifted its focus to green transformation and governance of highpolluting companies. In the context of green and sustainable development, this study employs DEA data envelopment analysis to compare the operating efficiency of listed firms that implemented Green Mergers and Acquisitions (M&A) in China in 2018. The conclusions of this study are as follows: First, China's green M&A enterprises are unevenly dispersed among the country's east, middle, and western regions. Second, compared to before the implementation of Green M&A, operational efficiency has improved in most industries. Third, the difference in Green M&A across industries is generally favorable, showing that most organizations have improved their operational performance as a result of Green M&A implementation. In 2018, however, the gap in operating efficiency is more negative. Fourth, whereas the eastern and western areas' operational efficiency has improved as a result of Green M&A, the central region's has not. Based on this conclusion, this study makes recommendations for China's future sustainable development of heavily polluted firms.

• Proceedings of KOSOMES biannual meeting
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• 2004.11a
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• pp.49-56
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• 2004

It has been estimated that up to $80\%$ of all marine accidents have human elements as a cause. t of these, human elements of crew fatigue is main causes of marine accident. Crew fatigue involves sleep, schedule. workload. off-time. alcohol health and stress. With a ship handling simulator, the effect of alcohol on ship operational performance is studied for each 0.05 and $0.08g\%$ blood alcohol concentrations. A main effect for alcohol was found indicating that ship operational performance was significantly impaired by this alcohol relative to performance in the non-alcohol condition. The results of this research can be applied to minimize marine accidents as basic data.

• Journal of Korean Elementary Science Education
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• v.19 no.1
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• pp.41-56
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• 2000

The purpose of this study was to investigate the change of elementary school students' conception on the movement of the moon, after teaching a lesson about the lunar phase which focused on concrete activities. The 396 subjects in this study consisted of intact groups of second, third, fourth, fifth, and sixth grade students. Pre-test and post-test instrument concerning on the conception in the movement of the moon were developed after reviewing the related literature and curriculum. Prevailing conceptions were identified by frequency of each conception. Then, the pattern of change and consistency of each conception were analyzed in comparison pre-test with post-test. To figure out the effect of teaching, the GEFT and the GALT instrument were administered to analyze it by gender, cognition mode and level. SPSS/WIN programs were used to process the data. The result showed that teaching 'movement of the moon' was the most effective in fourth grade. The effect of teaching 'changes in shape of the moon' was effective regardless of their sexes. Teaching 'changes in shapes of the moon' was more effective for the students whose cognitive modes were field-independent, than those filed-dependent. But the improvement by the teaching was not significantly different. The pre-score by cognitive level was significantly high in the order of the formal operational, transitional stage and the concrete operational stage. But the improvement of conception after teaching was high in the order of the concrete operational, transitional stage and the formal operational stage. That is to say, teaching was more effective as the cognitive level lowered.

• Membrane Journal
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• v.22 no.6
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• pp.489-501
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• 2012

The nitrogen removal characteristics of the MBR system consisted of two intermittent reactors, a membrane reactor and a deaeration reactor under constant flow and wastewater composition at different operational temperature and SRTs (Sludge Retention Times) were studied by computer simulation. The nitrogen removal efficiencies were dropped from 59% to 31%, when operational temperature was increased to $25^{\circ}C$ from $13^{\circ}C$ with same SRT of 25 days. Lower RBO (Readily Biodegradable Organic) concentrations at intermittent reactors at $25^{\circ}C$ compared with those at $13^{\circ}C$ of operational temperature were believed to be the main cause. The nitrogen removal efficiencies and RBO concentrations at each intermittent reactors were recovered when SRT was reduced to 12.6 days at $25^{\circ}C$. The effect of both SRT and operational temperature on RBO concentrations at intermittent reactors is need to be studied further.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.168-169
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• 2007

Organic transistors are promising in the future development of active devices for flexible, low-cost and large-area photoelectric devices. However, conventional organic field-effect transistors have lowspeed, low-power, and relatively high operational voltage. Vertical type transistors show high-speed and high-current characteristics and are suitable for driver elements of flexible displays.

• Atmosphere
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• v.32 no.2
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• pp.87-101
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• 2022

In this paper, the performance improvement for the new KMA's Climate Prediction System (GloSea6), which has been built and tested in 2021, is presented by assessing the bias distribution of basic variables from 24 years of GloSea6 hindcasts. Along with the upgrade from GloSea5 to GloSea6, the performance of GloSea6 can be regarded as notable in many respects: improvements in (i) negative bias of geopotential height over the tropical and mid-latitude troposphere and over polar stratosphere in boreal summer; (ii) cold bias of tropospheric temperature; (iii) underestimation of mid-latitude jets; (iv) dry bias in the lower troposphere; (v) cold tongue bias in the equatorial SST and the warm bias of Southern Ocean, suggesting the potential of improvements to the major climate variability in GloSea6. The warm surface temperature in the northern hemisphere continent in summer is eliminated by using CDF-matched soil-moisture initials. However, the cold bias in high latitude snow-covered area in winter still needs to be improved in the future. The intensification of the westerly winds of the summer Asian monsoon and the weakening of the northwest Pacific high, which are considered to be major errors in the GloSea system, had not been significantly improved. However, both the use of increased number of ensembles and the initial conditions at the closest initial dates reveals possibility to improve these biases. It is also noted that the effect of ensemble expansion mainly contributes to the improvement of annual variability over high latitudes and polar regions.