• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.7
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• pp.1047-1054
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• 2002

To improve the fuel consumption and exhaust emission for gasoline engines, GDI(Gasoline Direct Injection) system was spotlighted to solve above requirements. Thus, many researchers have been studied to investigate the spray characteristics and the mixture formation of GDI injector. In this study, we tried to study the spray characteristics of a gasoline direct injector by using entropy analysis and PlV methods. The entropy analysis is based on the concept of statistical entropy, and it identifies the degree of homogeneity in the fuel concentration. The PlV method was adopted to determine the fluid dynamics information at the spray. From the applied results on a direct injection gasoline spray, we could find that the direct diffusion phenomena was a dominant factor in the formation of a homogeneous mixture at downstream of GDI spray especially under vaporizing ambient conditions, and mixing phenomena was also progressed by momentum exchange with induced air. In addition, the correlation between entropy and vorticity strength enabled to find their relation.

• Geomechanics and Engineering
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• v.24 no.5
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• pp.491-503
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• 2021

Shallow tunnels are vulnerable to earthquakes, and shallow ground is usually inhomogeneous. Based on the limit equilibrium method and variational principle, a solution for the seismic collapse mechanism of shallow tunnel in inhomogeneous ground is presented. And the finite difference method is employed to compare with the analytical solution. It shows that the analytical results are conservative when the horizontal and vertical stresses equal the static earth pressure and zero at vault section, respectively. The safety factor of shallow tunnel changes greatly during an earthquake. Hence, the cyclic loading characteristics should be considered to evaluate tunnel stability. And the curve sliding surface agrees with the numerical simulation and previous studies. To save time and ensure accuracy, the curve sliding surface with 2 undetermined constants is a good choice to analyze shallow tunnel stability. Parameter analysis demonstrates that the horizontal semiaxis, acceleration, ground cohesion and homogeneity affect tunnel stability greatly, and the horizontal semiaxis, vertical semiaxis, tunnel depth and ground homogeneity have obvious influence on tunnel sliding surface. It concludes that the most applicable approaches to enhance tunnel stability are reducing the horizontal semiaxis, strengthening cohesion and setting the tunnel into good ground.

• Journal of Korea Water Resources Association
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• v.38 no.8 s.157
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• pp.617-629
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• 2005

In this paper, a hypothesis is tested that division of non-monotonic time series into monotonic parts will improve the estimation of trends through increased homogeneity in direction of time-variation using LOWESS smoothing and seasonal Kendall test. From the trend analysis of generated time series and water temperature, discharge, air temperature and solar radiation of Lake Daechung, it is shown that the hypothesis is supported by improved estimation of trends and slopes. Also, characteristics in homogeneity variation of seasonal changes seems to be more clearly manifested as homogeneity in direction of time-variation is increased. And this will help understand the effects of human intervention on natural processes and seems to warrant more in-depth study on this subject. The proposed method can be used for trend analysis to detect monotonic trends and it is expected to improve understanding of long-term changes in natural environment.

• Journal of Soil and Groundwater Environment
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• v.19 no.6
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• pp.49-58
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• 2014

This study was implemented as a part of the experiment to develop two kinds of soil-based Benzo[a]pyrene (BaP) proficiency testing materials (PTMs) for soil analysis. A test was carried out for the check of solubility of the reference material (high purity reagent) using several solvents. Another test was also conducted for the evaluation of homogeneity and stability of two kinds of candidate soil reference materials. The test analysis of BaP in terms of the candidate materials was conducted according to the Standard Soil Analytical Methods by Ministry of Environment. Dissolution of the reference material was shown to vary depending on solvent type and was higher in the order of Dichloromethane > Acetone > Acetone/MeOH (9 : 1) > N-hexane. In addition, the slope on calibration curve for BaP standard solutions was largest on BaP standard solutions prepared with dichloromethane of the tested solvents. Such tendency appeared egually in the commercial BaP standard solution. Therefore, it is thought to be reasonable to use dichloromethane as the solvent in case of the standard stock solution that is used for the measurement of BaP concentration in soil. ISO 13528 and IUPAC protocol were used for verification of homogeneity on the two kinds of soil candidate materials, Both candidate materials were sufficiently homogeneous. Stability assessment of the two candidate materials was made according to ISO Guide 35 and the result showed that both batches did not have any long-term and short term stability issues that might occur during shipping. However, monitoring results of BaP concentration in soil showed that BaP concentration of the two batches measured at 15 days after the sample preparation was reduced by about 24~37% compared with that of the samples measured on 0 day of the sample preparation. Identification was done with several treatments such as irradiation and sterilization etc. The major cause was shown to be irradiation to the samples.

• The Journal of Economics, Marketing and Management
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• v.12 no.1
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• pp.77-88
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• 2024

Purpose: By studying the effects of SNS advertising characteristics and SNS advertising music characteristics conducted by companies on advertising preference and advertising effects, we would like to suggest a plan for effective SNS advertising operation. Research design, data and methodology: In this study, a total of 483 surveys were collected for college student consumers in their 20s who had experience seeing advertisements on SNS, and 458 were used for the final analysis. In addition, the collected questionnaire data were analyzed using statistical programs SPSS 24.0 and AMOS 24.0, and Sobel Test was performed through structural equation modeling and regression analysis. Results: Advertising preference, purchase, and recommendation intentions increased as consumers who saw advertisements on SNS perceived the characteristics of advertisements (information, entertainment, individuality, and interactivity). However, advertising preference was not formed by SNS advertising music characteristics (fun, information delivery, unconscious stimulation, and emotional homogeneity). In addition, the higher the perception of SNS advertising music characteristics (fun, information delivery, unconscious stimulation, and emotional homogeneity), the more advertising effects such as purchase and recommendation intentions were linked, and the higher the perception of SNS advertising music characteristics (fun, information delivery, unconscious stimulation, and emotional homogeneity), the more advertising effects such as purchase and recommendation intentions could be created. Finally, it was confirmed that advertising preference had a partial mediating effect between SNS advertising characteristics and advertising effects, and between SNS advertising music characteristics and advertising effects. Conclusions: Unlike previous studies that have investigated the causal relationship of advertising effects according to sub-factors such as SNS advertising characteristics and SNS advertising music characteristics, it is significant in that it analyzes the variables used in the study as secondary factors.

• Fashion & Textile Research Journal
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• v.26 no.1
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• pp.88-98
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• 2024

With the growing preference among Chinese consumers for purchasing beauty products through social media networks (SNS), influencer marketing has recently emerged as a crucial strategy for maximizing word-of-mouth effects. This study aims to ascertain the impact of SNS beauty influencers' characteristics on trustworthiness and consumers' intentions to engage in word-of-mouth promotion. Furthermore, the study seeks to explore the moderating role of consumer involvement in the relationship between SNS beauty influencer characteristics and the trust consumers place in them. As part of an empirical analysis, an online survey was administered to 259 Chinese female consumers who had previously purchased beauty products through influencers on SNS. The data gathered were scrutinized by conducting multiple and hierarchical regression analysis to test the proposed hypotheses. The findings indicated that the attributes of "expertise,"' "intimacy," and "homogeneity" in SNS beauty influencers significantly affect influencer trust, whereas "charm" does not have a significant impact. Moreover, consumer involvement was found to moderate the relationship between SNS beauty influencer characteristics (expertise, intimacy, charm, and homogeneity) and influencer trust. Additionally, influencer trust positively influenced the intention to engage in word-of-mouth activities. These findings signify that leveraging influencers possessing qualities such as expertise, intimacy, and homogeneity can help enhance product exposure, popularity, and sales of the beauty industry. This study contributes valuable insights into the strategic utilization of influencer characteristics in the beauty industry and digital marketing, highlighting their pivotalrole in consumer engagement and the success of marketing strategies.

• The Journal of Korean Medicine
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• v.25 no.2
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• pp.77-86
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• 2004

Objectives: To study the features of appetite and dining habit according to Sasang constitution. The results of this study will be helpful to diagnose a Sasang constitution. Methods: There were 588 patients (248 men, 340 women) who answered questionnaire and were diagnosed by the Sasang Constitution Specialist at the Constitutional Clinic of Dongguk Bundang Oriental Hospital. Using the responses to the questionnaire and several statistical techniques such as homogeneity test and multiple comparison, we tried to find the characteristics of each constitution depending on its dining behavior. Results & Conclusions: As a result of the analysis of the questionnaire, Taeumin and Soyangin have a heavy appetite (p<0.01), but the appetite of Soyangin and Soeumin tends to be irregular (p<0.01). Especially, the appetite of Soeumin tends to change according to his feelings (p<0.0I). Taeumin and Soyangin eat more and faster in comparison with Soeumin (p<0.01).

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.4
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• pp.38-48
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• 2011

Block based LCD backlight nonideality and crosstalk compensation methodologies are proposed based on the analysis of backlight profiles and image pixel homogeneity. Large computation complexity required in the conventional compensations is minimized without the degradation of image qualities by optimizing image block size, image area inside the block to be excluded from the compensation computation and the required backlight range to be computed. The optimization results of computation complexity as well as image qualities are verified for the proposed compensation by real image data simulations.

• Communications for Statistical Applications and Methods
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• v.16 no.2
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• pp.389-396
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• 2009

Approximations for the null distribution of a test statistic arising in multivariate analysis to test homogeneity of variances and a mixture of two beta distributions by making use of a product of beta baseline density function and a polynomial adjustment, so called beta-polynomial density approximant, are discussed. Explicit representations of density and distribution approximants of interest in each case can easily be obtained. Beta-polynomial density approximants produce good approximation over the entire range of the test statistic and also accommodate even the bimodal distribution using an artificial example of a mixture of two beta distributions.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.6
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• pp.49-60
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• 2002

This study was conducted to estimate the design flood by the determination of best fitting order of LH-moments of the annual maximum series at six and nine watersheds in Korea and Australia, respectively. Adequacy for flood flow data was confirmed by the tests of independence, homogeneity, and outliers. Gumbel (GUM), Generalized Extreme Value (GEV), Generalized Pareto (GPA), and Generalized Logistic (GLO) distributions were applied to get the best fitting frequency distribution for flood flow data. Theoretical bases of L, L1, L2, L3 and L4-moments were derived to estimate the parameters of 4 distributions. L, L1, L2, L3 and L4-moment ratio diagrams (LH-moments ratio diagram) were developed in this study. GEV distribution for the flood flow data of the applied watersheds was confirmed as the best one among others by the LH-moments ratio diagram and Kolmogorov-Smirnov test. Best fitting order of LH-moments will be derived by the confidence analysis of estimated design flood in the second report of this study.