• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.8
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• pp.14-20
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• 2009

In this paper, the time-varying failure rate to consider climate effect was extracted. Even if the same kind of equipments is estimated for extracting the time-varying failure rate, the failure rates could be different depending on external effect such as climate. With the consequence, the failure rate extracted to consider the climate effect is necessary for using the failure rate on the optimal investment plan or asset management, To consider the characteristic of climate effects(Classified into 5 categories, heavy rain, thunderbolt, strong wind, tidal waves, no character), the survey of officers charging the operation of equipment in KEPCO branch office was done. With this consequence, this paper suggest the failure rate extraction method to consider the climate effect analyzed by the survey.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.916-923
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• 2005

In this study, to observe aging effect of undrained shear behavior for Nak-Dong River sand, undrained static and cyclic triaxial tests were performed with changing relative density ($D_r$), consolidation stress ratio($K_c$) and consolidation time. As a result of the test, the modulus of elasticity to all samples estimated within elastic zone by the micro strain of about 0.05% in case of static shear behavior increased with the lapse of consolidation time significantly, so aging effect was shown largely. Also strength of phase transformation point(S_{PT}$) and strength of critical stress ratio point($S_{CSR}$) increased with the lapse of consolidation time. Undrained cyclic shear strength($R_f$) obtained from the failure strain 5% increased in proportion to relative density($D_r$) and initial static shear stress($q_{st}$), $R_f$ of consolidated sample for 1,000 minutes increased about 10.6% compared to that for 10 minutes at the loose sand, and $R_f$ increased about 7.0% at the medium sand. In situ application range of $R_f$ to the magnitude of earthquake for Nak-Dong River sand was proposed by using a increasing rate of $R_f$ as being aging effect shown from this test result.

• Fashion & Textile Research Journal
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• v.22 no.1
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• pp.38-54
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• 2020

This study examines the time causal relationship between the operation profit of the listed fashion companies and the macro variables. Operating profit data of 36 listed fashion companies from 2000 to 2017 has been used. Macro variables include household income, household expenditure, number of Korean overseas travelers, number of foreigner travelers and sentiment index. The study results are as follows. First, the number of outbound travelers from Korea has a negative effect on the operating profit of listed fashion companies; however the number of foreigner visiting Korea has a positive effect at 0 time lag. Second, the consumer sentiment index had a positive effect on the sales and the operating profits of the listed fashion companies with a time difference between the 3rd and the 4th quarter. Third, a disposable income has a positive effect on the operating profit of listed fashion companies. Last, educational expenses have a negative effect on operating profit with a time lag between the first and the second quarter. The findings can be used as useful information to analyze the fashion industry and help fashion companies improve their financial performances.

• Geomechanics and Engineering
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• v.33 no.5
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• pp.519-528
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• 2023

In this paper, we present the results of an experimental study on the effect of polymer support fluid on shaft resistance of offshore bored piles. A series of pullout tests were performed on bored piles installed under various boundary conditions considering different types of grounds and support fluids, and a range of support fluid exposure times. Contrary to previous studies concerning onshore bored piles, a time dependent effect of polymer fluid on shaft resistance was observed in all ground types. The adverse effect of polymer support fluid on the shaft resistance, however, was considerably less than bentonite support fluid for a given exposure time. No significant reduction in shaft resistance was evident when limiting the exposure time of the polymer support fluid to the side wall of the borehole within 2-3 hours. The degree to which the polymer fluid affects shaft resistance seemed to vary with the ground type. A proper consideration should be given to the time dependent effect of polymer fluid on shaft resistance of bored piles installed in offshore construction environment to limit its adverse effect on the pile performance. The practical implications of the findings are discussed.

• Journal of the Korean Wood Science and Technology
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• v.27 no.4
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• pp.20-29
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• 1999

Temperature has important effect on mechanical properties of wood. These effect needs to be understood and taken into account in the structural use of wood. Furthermore, the effect of cooling after exposing to high temperature must be explained. In this study, the effect of temperature, exposure time, specific gravity, and cooling on bending properties were investigated. The boundary temperatures at which bending MOE and MOR reduced rapidly were approximately $200^{\circ}C$ and $150^{\circ}C$, respectively. This boundary temperature was nearly constant with independence of species(specific gravity), exposure time, and cooling. Above the boundary temperature, the effect of exposure time was increased with temperature and the reduction of bending MOE and MOR for Japanese Larch with relatively higher specific gravity was smaller than that of Hem-fir. The recovery of bending MOE and MOR after cooling was also more significant above the boundary temperature than below. The degree of cooling effect was larger for MOR than MOE. Consequently, bending properties of wood in elevated temperatures should be considered in terms of the boundary temperature, $200^{\circ}C$ for bending MOE, $150^{\circ}C$ for MOR, and these boundary temperatures must be considered an important factor. Furthermore, to evaluate the safety of structure, the recovery after cooling should be considered.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2008.10b
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• pp.235-245
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• 2008

The interactive advertisement is already on satellite and cable broadcasting hereafter the introduction of this system is concerned on terrestrial programs. This study is to research the effectiveness of interactive TV advertising focusing on factors of involvement and interaction. Study started for the effect measurement of interactive television advertisement. Interactive television advertisement has different concept than existing television advertisement. Thus, the effect also needs to examine in other methods. Study is mainly focusing on the characteristics of interactive and the experiments, which was based on existing data, for measurement of effect. In the experiments, the characteristics were categorized in a search time, a number of searched pages about interactive television advertisement. The research finds that the involvement of the audience increases when the interaction of advertising attitude, brand attitude, and purchase intentions also increases. And so, a successful interactive TV advertisement results in longer searching hours and greater it visits by the audience when the interaction factors are considered and increased. By study of consumer's characteristics and behavior, a new method of the effect measurement for interactive television advertisement is provided. The new method includes not only existing measurement elements of television advertisement which are attitude on advertising and brand, and customers' purpose, but also the features of interactive television advertisement, which are search time, a number of searched pages. Recently added features provides data of the effect on high/low groups and it contributes to the process of interactive television advertisement. Study on interactive television advertisement will be helpful to plan an effective strategy by suggesting the theoretical evidence of its effect.

• The Journal of Pediatrics of Korean Medicine
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• v.22 no.1
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• pp.1-11
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• 2008

Objectives In order to investigate the anticonvulsive effects of Jisungbomuyngtan, the experiments were done in mice. Methods After solid extracts of Jisungbomuyngtan was orally administered to mice, four types of convulsion were induced in mice by ECT, strychnine, picrotoxin, caffein. Each of the time to convulsion and death was measured. Results 1. The solid extracts of Jisungbomuyngtan showed a remarkable effect in delaying the onset of convulsion induced by ECT 2. In case of convulsion induced by strychnine, the solid extracts of Jisungbomuyngtan revealed a slight, but not statistically significant effect. 3. Considerable prolongation of time to death was observed in convulsion induced by picrotoxin due to the anticonvulsive effect of Jisungbomuyngtan. 4. The anticonvulsive effect of Jisungbomuyngtan was not found in convulsion induced by caffein. Conclusions Jisungbomuyngtan effect remarkably in delaying the onset of convulsion induced by ECT. But slightly effect by strychnine. And Jisungbomuyngtan effect in prolonging time to death in convulsion induced by picrotoxin, but not found in convulsion induced by caffein.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.922-924
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• 1995

The modeling of accurate timing in storage elements of ASIC cell library was studied. The propagation delay time of clock signal affects the critical time and this can cause malfunction in the chip designed in synchronous. In this paper, an analysis on the effect of input slope of clock signal in timing modeling were carried out. For the first time, in ASIC design, the design guides that can be used in both $0.6{\mu}M$ and $0.8{\mu}m$ design rule were offered, reducing the run time of SPICE and the time of cell library development.

• The Research Journal of the Costume Culture
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• v.28 no.6
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• pp.875-889
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• 2020

This study examined the effect of Instagram usage time (short, long) and spending on fashion products (light, heavy) on product attitude and purchase intention of products promoted by an influencer. The moderating effect of influencer type (mega, macro, micro) was also investigated. A total of 515 males and females in their 20s participated in an online survey. Descriptive statistics were analyzed and exploratory factor analysis and two-way ANOVA were conducted. Research findings were as follows. First, the usage time, both short and long, had a positive effect on product attitude. Also, the interactive effects of usage time and influencer type on product attitude were found. Consumers with short Instagram usage time displayed the highest attitude toward products promoted by a macro-influencer whereas consumers with long Instagram usage time displayed the highest attitude toward products promoted by a micro-influencer. Second, usage time and influencer type did not show interactive effects on purchase intention. Third, both categoriacl variables of users' spending on fashion products had a positive effect on product attitude. Fourth, the interaction effects of spending on fashion products and influencer types on purchase intention were found. The group of light buyers showed the highest purchase intention on products promoted by the macro-influencer while the group of heavy buyers showed the highest purchase intention of products promoted by the micro-influencer. Based on the results, implications were suggested.

• The Korean Journal of Applied Statistics
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• v.36 no.5
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• pp.415-445
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• 2023

Oftentimes, the time dependent treatment covariate and the time dependent confounders exist in observation studies. It is an important problem to correctly adjust for the time dependent confounders in the propensity score analysis. Recently, In the survival data, Hade et al. (2020) used a propensity score matching method to correctly estimate the treatment delay effect when the time dependent confounder affects time to the treatment time, where the treatment delay effects is defined to the delay in treatment reception. In this paper, we proposed the Cox model based marginal structural model (Cox-MSM) framework to estimate the treatment delay effect and conducted extensive simulation studies to compare our proposed Cox-MSM with the propensity score matching method proposed by Hade et al. (2020). Our simulation results showed that the Cox-MSM leads to more exact estimate for the treatment delay effect compared with two sequential matching schemes based on propensity scores. Example from study in treatment discontinuation in conjunction with simulated data illustrates the practical advantages of the proposed Cox-MSM.