• Composites Research
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• v.26 no.2
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• pp.116-122
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• 2013

In this study, impact behavior of aluminium and glass-fiber structure is studied under low impact velocity. Compression test is carried out to investigate the compressive strength of the specimens. The degree of damage is observed using microscopy and compared with the experimental analysis data. The maximum load capacity, impact strength and elastic energy of glass-fiber honeycomb sandwich panel are more than the aluminium honeycomb sandwich panel.

• The Journal of the Korean dental association
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• v.52 no.5
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• pp.291-301
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• 2014

Korea Health Panel Survey (KHPS) has been conducted to provide nationally representative estimates of health care use and expenditures for non-institutionalized population in Korea since 2008. The aim of this study was to present estimates from KHPS on dental utilization and expenditures from 2008 to 2011. While weighted estimates were presented for each year from 2008 to 2011, the focus of this study was on the 2011 estimates and changes in dental utilization and expenditures between 2008 and 2011. Weighted estimates were obtained using population weights and statistical significances were analysed by independent t-test or ANOVA test using SPSS version 20 for Windows. In 2011, 21.1% of Korean population obtained outpatient dental services from dentists. From 2008 to 2011, the percent of people with a dental visit in each year increased slightly. In 2011, the mean number of dental visits was 4.46. While the mean number of dental visits remained stable by 2010, it increased slightly in 2011. The total annual dental expense in 2011 for people with a visit was about 460,000 Korean Won and 10% higher in 2008. In summary, this study results highlight low rates of dental utilization and high dental expenses in Korean population.

• Journal of the Ergonomics Society of Korea
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• v.28 no.3
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• pp.27-31
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• 2009

To evaluate the usability of a Kimchi refrigerator, we performed an evaluation test that consisted of an experiment and a post-hoc questionnaire survey. In this study, we focused on the older women who have less physical and cognitive ability than younger women. In physical usability, there was no significant difference between the older and the younger subject group. However, there was some significant statistical difference in the results of cognitive usability test. When the subjects debriefed their operations after finishing the experiment, the all subjects in the older group reported the difficulties in identifying the labels and icons in the control panel and in understanding operation sequences. Also, they couldn't learn and remember the operation procedures well. Based on the analysis of the video protocols, some causes of the problems were found and then several improvement ideas were suggested.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.6
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• pp.264-270
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• 2020

Design was developed through user-oriented service design methodology and survey was conducted on material selection criteria for prototype production to select CFRP (Carbon Fiber Reinforced Plastics) CNT (Carbon Nano Tube), which was applied to animal X-ray detector panel to design product and develop prototype. Completed prototype with the application of CFRP CNT panel was tested in drop test, frontal external pressure test, and dustproof/waterproof performance to confirm that it can be utilized as a portable animal X-ray detector used in outdoor environment.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.2
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• pp.453-463
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• 2021

Economic globalization provides a good channel for the development of foreign trade around the world. Due to this background, this paper sets the Organization for Economic Co-operation and Development (OECD) countries as a sample to explore the importance of international logistics in foreign trade. An annual panel data from 2000 to 2017 will be used to conduct an empirical estimation under the panel unit root test and the fixed effect model. Foreign trade is treated as an explained variable and international logistics is treated as explanatory variables. The findings show that international logistics have a positive spillover effect on export trade and the speed of international logistics development has a regulatory effect on the relationship between both of them, which presents a U-shaped curve. When the speed of international logistics development is slow, an increase of it restrains the positive spillover effect of international logistics on export trade. However, when it rises to a certain extent, this increase releases the positive spillover effect of international logistics on export trade. As can be seen by the evidence that this paper provides, the impact of international logistics on foreign trade is dynamic. Moreover, this paper also puts forward some corresponding measures about the relationship between both of them.

• Advances in aircraft and spacecraft science
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• v.9 no.5
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• pp.377-400
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• 2022

The aim of this work is a numerical comparison (FEM) between lattice pyramidal-core panel and honeycomb core panel for different core thicknesses. By evaluating the mid-span deflection, the shear rigidity and the shear modulus for both core types and different core thicknesses, it is possible to define which core type has got the best mechanical behaviour for each thickness and the evolution of that behaviour as far as the thickness increases. Since a specific base geometry has been used for the lattice pyramidal core, the comparison gives us the opportunity to investigate the unit cell strut angle giving the higher mechanical properties. The presented work considers a detailed FEM modelling of a standard 3-point bending test (ASTM C393/C393M Standard Practice). Detailed FEM modelling addresses to detailed discretization of cores by means of beam elements for lattice core and shell elements for honeycomb core. Facings, instead, have been modelled by using shell elements for both sandwich panels. On lattice core structure, elements of core and facings are directly connected, to better simulate the additive manufacturing process. Otherwise, an MPC-based constraint between facings and core has been used for honeycomb core structure. Both sandwich panels are entirely built of Aluminium alloy. Prior to compare the two models, the FEM sandwich panel model with lattice pyramidal core needs to be validated with 3-point bending test experimental results, in order to ensure a good reliability of the FEM approach and of the comparison. Furthermore, the analytical validation has been performed according to Allen's theory. The FEM analysis is linear static with an increasing midspan load ranging from 50N up to 500N.

• Korea Trade Review
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• v.41 no.5
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• pp.373-389
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• 2016

This study mainly investigates the port SOC's impact on trade volume. In order to investigate the relationships between port SOC and trade volume, we did the empirical analysis using panel data regression and fixed effects model. The total period of 97 years and 1,082 ports' information were applied to panel data and regression model. According to the results, the coefficients of development of container berth, development of bulk berth, maintenance of port, the jetty facilities like breakwater have positive(+) impact on the dependent variable, the trade volume. Especially, the jetty facilities show a strongly positive impact on trade volume. On the other hand, the development of new port and navigation facilities like lighthouse have a negative(-) impact. In examining Hausman test and LR test, the fixed effect model is statistically more appropriate than the random effect model for this study.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.55-58
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• 2004

High Xe-content PDP characteristics are discussed. A high efficacy, up to 5 lm/W for a 50% Xe in Ne gas mixture, is realized in 4-inch color PDP test panel designs with low cost stripe-type barrier rib structures, that are powder blasted in soda lime glass. Furthermore, for a high Xe-content a high luminance can be obtained with a relatively small electrode area. Therefore the inter cell gap and the driving margin can be increased in a stripe-type barrier rib structure. Finally, for a high Xe-content the panel lifetime increases, due to increasing luminance and firing voltage stability. Clearly, these findings may direct the design development for next generation PDPs towards a high Xe-content

• Applied Biological Chemistry
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• v.20 no.3
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• pp.270-278
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• 1977

In case of sensory evaluation with multi-samples and long-period, in spite of using method with good sensitivity, quality differences among samples could net be detected well because of panel's fatigue and tiredness. So new method to reduce panel's sense of psychological and physiological responsibility, "Trio Paired Comparison", is designed, and New Modified Scheffe's Method 2 as the statistical method for a test of "Trio Paired Comparison" is proposed. And also in this paper problems and countermeasures in applicating "Trio Paired Comparison" are considered.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1621-1624
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• 2008

Transparent ac-PDP test panel was prepared via a combination of materials including ITO sustaining electrodes, thin film dielectric layer and nano-sized phosphor powders. The thin film dielectric layer was prepared by E-beam evaporation process and phosphor layer was deposited on metal mesh pattern by electrophoretic deposition process. The optical transmittance and luminance of the panel indicated that full color transparent ac-PDP is feasible with the approach.