• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.160.1-160.1
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• 2011

In this study, the influence of methodology of assessing water levels on the discharge coefficient of sluice for tidal power generation was investigated. A physical experiment was performed in a planar open channel by installing 1/70 scale model of the sluice caisson in the planar open channel. In front of and behind the sluice model, sloping bathymetry was made to reproduce corresponding field condition. By analyzing the experimental results, it was found that the location of measuring water levels significantly affects the estimates of the discharge coefficient, due to the variability of the parameter according to the head difference between the measuring locations. Therefore, it is necessary to be careful in estimating and utilizing the discharge coefficient in the relevant study of a tidal power generation.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.197-198
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• 2023

Construction waste takes about 50% of total industrial waste. Researchers focuses to decrease the amount of construction waste by recycling the waste during the construction site. However, research about recycling the gelatin-sand composite is not yet been studied. This research is an experimental research on recycling the total specimen of gelatin-sand composite. Two methods were held when making the 2^nd generation of the gelatin-sand specimen. As a result, there was no difference in flexural strenght between two different method of 2^nd generation of specimen. However, the second method of 2^nd generation showed about 20% higher compressive strength than the first method.

• Journal of Korea Technology Innovation Society
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• v.9 no.3
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• pp.451-470
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• 2006

This study aims to test factors on the success of Employee Suggestion Systems (ESS). Considering the difference between manufacturing and non-manufacturing firms in the use of ESS, this study analyzes the impact of the industrial sector. Partial Least Square (PLS) is employed to analyze data front employees in an automobile company and a bank. The result shows that there is no distinctive difference between two industries but there are some differences in the strength of the relationships such as e impact of pro-activity on idea generation, the work improvement on idea generation and idea generation on idea submission. Some suggestions for managing ESS in non-manufacturing firms are presented.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.6
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• pp.379-385
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• 2019

Dynamic Tidal Power, which is a kind of tidal power generation, requires huge structures, because it is conducted by using the phase difference caused by the diffraction effect of tides. Economic feasibility is most demanded for practical use, and various studies have been conducted for this purpose. In this study, unlike existing methods, several structures were installed to improve it by increasing power generation. The flow changes around the structures were studied, and it was found that proper spacing between structures was necessary for efficient power generation.

• Transactions on Electrical and Electronic Materials
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• v.17 no.1
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• pp.21-24
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• 2016

A junction box used in a 3 kW photovoltaic power generation system plays a role in collecting and supplying the direct current voltage produced by photovoltaic modules to an inverter. It is also used for facilitating maintenance checks and protecting the module and inverter by keeping the voltage constant. As for the junction box, using it in a parallel connection creates a difference between the setup modules. In order to compensate, an inverse voltage diode is used. But the high-power created through the solar generator can be delivered to the inverter through the inverter regularly. Therefore, a component can break down due to excess heat. And consequently short circuits and electric leakage occurs. In this study, using a junction box that enabled the bypass of high electric power, it was possible to reduce heat generation by approximately 35℃ when compared to a standard junction box.

• MALSORI
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• no.57
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• pp.15-30
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• 2006

This paper investigates differences between generations in the vowel system of the Daegu dialect in terms of F1 and F2 of the monophthongs. Three different groups of subjects participated in the present study: 20 female native speakers of the Daegu dialect(10 in their 20's and 10 in their 40's), and 10 female native speakers of the Seoul dialect as a control group. It has been assumed that the Daegu dialect has six vowels. However, younger generation appears to have 7 vowels different from older generation. The result of the present study showed that the Daegu dialect has different vowel systems between generations: for 40's have six vowels and 20's have seven vowels. These differences seems to be attributed to the influence of the Seoul dialect.

• Nuclear Engineering and Technology
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• v.40 no.4
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• pp.299-304
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• 2008

A detection system was set up to measure the neutron generation rate of a recently developed D-D neutron generator. The system is composed of a Si detector, He-3 detector, and electronics for pulse height analysis. The neutron generation rate was measured by counting protons using the Si detector, and the data was crosschecked by counting neutrons with the He-3 detector. The efficiencies of the Si and He-3 detectors were calibrated independently by using a standard alpha particle source $^{241}Am$ and a bare isotopic neutron source $^{252}Cf$, respectively. The effect of the cross-sectional difference between the D(d,p)T and $D(d,n)^3He$ reactions was evaluated for the case of a thick target. The neutron generation rate was theoretically corrected for the anisotropic emission of protons and neutrons in the D-D reactions. The attenuations of neutron on the path to the He-3 detector by the target assembly and vacuum flange of the neutron generator were considered by the Monte Carlo method using the MCNP 4C2 code. As a result, the neutron generation rate based on the Si detector measurement was determined with a relative uncertainty of ${\pm}5%$, and the two rates measured by both detectors corroborated within 20%.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.156-157
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• 2003

The wavelength converter is considered to be a key element of future dense WDM optical networks. It enables wavelength reuse and resolves contention problem. Moreover, the tunability of the wavelength converter enhance the flexibility of network systems by facilitating reconfigurable dynamic wavelength routing. In order to achieve optically tunable wavelength conversion, we recently proposed and experimentally demonstrated wavelength conversion and tuning based on cascaded sum and difference frequency generation in a Ti：PPLN channel waveguide. (omitted)

• Journal of Welding and Joining
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• v.21 no.1
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• pp.48-53
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• 2003

The object of this study is to examine the effect of short circuit time ratio (SCTR) and current rise delay time (Td) on the spatter generation at low and medium current range in $CO_2$ welding. The spatter was evaluated by the weight generated in the welding of bead-on-plate for 30 seconds (3 times). Td was varied by order of 0, 0.4, 0.8 and 1.2 msec. At each Td, the short circuit time ratio was varied by the output voltage of the welding power source. In the low current range, it was found that the optimum SCTR was 20~25%, and the minimum spatter generation weight was obtained in the case of Td=0.4msec and SCTR=22% even though the remarkable difference was not showed by the application of Td. In the medium current range, it was confirmed that the arc was stable though the SCTR was increased from 20% to 40% by the control of current wave. Spatter generation weight depended on the variation of Td, and the lowest value of spatter generation weight occurred at Td=0.8~1.2msec.

• The Journal of the Korea Contents Association
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• v.21 no.4
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• pp.591-602
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• 2021

The purpose of this study is to compare and analyze the factors influencing happiness between the baby boom generation and the elderly generation, and to clarify the difference in the factors affecting happiness in old age. Thus, using the data of the '2019 Seoul Survey Urban Policy Indicators Survey', a total of 15,451 people including 7,831 baby boomers (born 1955-1963) and 7,620 seniors (born before 1954) were sampled. Through regression analysis, we analyzed what factors affect happiness. As a result of the analysis, family relations were the most influential factor of happiness in both groups, but next, satisfaction through participation in leisure activities for baby boomers and economic support for elderly generations had a great influence on happiness. In addition, the degree of participation in SNS, which has no effect on the baby boom generation, is a significant factor influencing happiness for the elderly, showing that participation in the digital environment is important to the elderly. In the results of this study, it was suggested that the baby boom generation and the elderly generation are significantly different in terms of group characteristics, and therefore their social needs for the pursuit of happiness in their old age should be approached differently.