• Journal of Preventive Medicine and Public Health
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• 제56권4호
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• pp.303-311
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• 2023

Traditional mediation analysis, which relies on linear regression models, has faced criticism due to its limited suitability for cases involving different types of variables and complex covariates, such as interactions. This can result in unclear definitions of direct and indirect effects. As an alternative, causal mediation analysis using the counterfactual framework has been introduced to provide clearer definitions of direct and indirect effects while allowing for more flexible modeling methods. However, the conceptual understanding of this approach based on the counterfactual framework remains challenging for applied researchers. To address this issue, the present article was written to highlight and illustrate the definitions of causal estimands, including controlled direct effect, natural direct effect, and natural indirect effect, based on the key concept of nested counterfactuals. Furthermore, we recommend using 2 R packages, 'medflex' and 'mediation', to perform causal mediation analysis and provide public health examples. The article also offers caveats and guidelines for accurate interpretation of the results.

• Journal of information and communication convergence engineering
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• 제22권2호
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• pp.153-158
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• 2024

This study aims to summarize the effects of Arduino-based educational programs through a meta-analysis. Eleven eligible primary studies were obtained through a systematic literature review and coded accordingly. The results are as follows: The meta-analysis revealed that the overall effect size for all the studies was 0.518. Analysis of the moderator variables indicated statistically significant differences between them. Regarding the learning domains, the results were ranked in descending order of the cognitive and affective domains. Within the cognitive domain, the effect sizes were ranked in descending order as follows: logical thinking, content knowledge, convergence competency, self-efficacy, computational thinking, and creative problem-solving skills. In terms of subject areas, the descending order of effect sizes was agriculture, STEAM, environmental science, practical arts, artificial intelligence, informatics, and computers. Regarding school level, the results were ranked in the following descending order: college, elementary school, middle school, and high school.

• Asia Pacific Journal of Business Review
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• 제1권2호
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• pp.37-62
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• 2017

To analyze the effects of R&D expenditure on the firm value of Korean firms, we classified portfolios based on R&D activity levels. After that, we conducted a time-series analysis to assess excess returns from the portfolios. To carry out such an analysis, an empirical analysis of excess returns in the capital market was performed by using the monthly earning rate of stocks from 2000 to 2013. The purpose of this research is to provide basic data on investment to stakeholders in the capital market by analyzing the effects of R&D on the firm value and to overcome scholarly limitations by offering a new model of analysis. The criteria for classifying the portfolios were based on R&D expenditure levels. The analysis models follow the Fama-French Three-Factor Model and the Carhart Four-Factor Model. The analyses results are as follows. Extrapolating monthly profit rates based on R&D expenditure levels, portfolios with low R&D expenditures showed higher earning rates than those with high R&D expenditures. This suggests that high R&D expenditures did not translate into high earning rates. The investor depreciates the R&D expenditures related profitability and the possibility of success in the market, leading to falls in stock prices and a failure to give a positive effect on the firm value. Our research differs from the previous investigations as we carried out an empirical analysis based on the actual investors' attitudes about R&D expenditures and how these can generate excess earnings. Our research results show that the data related to R&D expenditure are not reflected fully in the market.

• 한국항행학회논문지
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• 제27권4호
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• pp.436-446
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• 2023

안전 필수 분야의 전장 장비에서 다양한 고장요인 (고장모드)에 따른 고장 영향 분석 (FMEA, Failure Mode and Effects Analysis)이 필수적이다. 이는 기기나 시스템의 잠재적인 결함들을 식별하고, 그로 인한 발생 가능한 위험을 평가하여 이를 방지하거나 관리하기 위한 개선안을 수립한다. 그러나 최근 시스템의 복잡성이 증가하고 소프트웨어의 영향이 중요해지며 전통적인 FMEA 만을 설계 단계에 적용하는 것이 어려운 상황이다. 본 논문은 모델기반설계기법을 기반으로한 Automatic FMEA 방식을 제안한다. 모델의 구조와 동작을 자동으로 분석하여 FMEA를 수행할 수 있게 하여, 설계 초기 단계에서도 고장모드 분석이 가능하게 한다. 사례연구로 차량 연료 제어 시스템을 대상으로 Automatic FMEA를 수행하였다. 본 연구는 Automatic FMEA 분석도구의 성능을 입증하는 동시에, 향후 연구 방향을 제안한다.

• 아동학회지
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• 제25권4호
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• pp.163-175
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• 2004

In this study, 63 university seniors majoring Child Studies were in an 8-week Web Based Instruction (WBI) program. Student characteristics of learning motivation, self-regulatory learning strategy, and learning style (Kolb, 1985) were the independent variables. Learning effects as dependent variables were measured by paper test and work assessment. Spearman's $\rho$ was calculated and tests of rank order difference were used for the data analysis. Results showed that learning motivation and self-regulatory learning strategy had meaningful positive relations with learning effects on the paper test score. Learning effects showed differences by learning style. These findings indicated that the learner's characteristics should be considered in the design and development of more effective WBI environments.

• Journal of Information Technology Applications and Management
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• 제13권1호
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• pp.67-75
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• 2006

In this paper, we investigate the economic repercussion effects of the domestic satellite industry. The market size of the satellite industry between 2005 and 2009 is forecasted based on the world market forecast. By using the Input-Output analysis technique, three kinds of repercussion effects (domestic production, value added, workers induced by the satellite industry) between 2005 and 2009 are calculated.

• 한국식품과학회지
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• 제47권5호
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• pp.615-622
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• 2015

The objectives of this study were to evaluate the sensory properties of various natural flavor enhancers (NFEs) and to understand the effects of NaCl and temperature on the sensory characteristics of these NFEs. Descriptive analysis was conducted to evaluate six types of NFEs: yeast extract-based NFE, three; fish sauce-based NFE, one; soy sauce-based NFE, one; and hydrolyzed peptide NFE-based, one. The effects of NaCl (no addition vs. addition) and temperature ($20^{\circ}C$ vs. $55^{\circ}C$) were also evaluated. The results showed that the overall flavor intensity and sensory properties of the NFEs differed greatly depending on the NFE source. Two of the yeast extract-based NFEs elicited higher umami intensity than the other NFEs. Addition of NaCl increased some of the savory-related flavors and the perceived viscosity of the sample. Aroma intensities, in general, were enhanced at the higher temperature, whereas flavor, aftertaste, and mouthfeel attributes were perceived to be stronger at the lower temperature.

• Genomics & Informatics
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• 제12권4호
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• pp.254-260
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• 2014

Best linear unbiased prediction (BLUP) has been used to estimate the fixed effects and random effects of complex traits. Traditionally, genomic relationship matrix-based (GRM) and random marker-based BLUP analyses are prevalent to estimate the genetic values of complex traits. We used three methods: GRM-based prediction (G-BLUP), random marker-based prediction using an identity matrix (so-called single-nucleotide polymorphism [SNP]-BLUP), and SNP-SNP variance-covariance matrix (so-called SNP-GBLUP). We used 35,675 SNPs and R package "rrBLUP" for the BLUP analysis. The SNP-SNP relationship matrix was calculated using the GRM and Sherman-Morrison-Woodbury lemma. The SNP-GBLUP result was very similar to G-BLUP in the prediction of genetic values. However, there were many discrepancies between SNP-BLUP and the other two BLUPs. SNP-GBLUP has the merit to be able to predict genetic values through SNP effects.

• Wind and Structures
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• 제31권5호
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• pp.459-472
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• 2020

This study focused on the non-synoptic, tornado-like wind-induced effects on flexible horizontal structures that are extremely sensitive to winds. More specifically, the nonuniform, intensive vertical wind-velocity and transient natures of tornado events and their effects on the global behavior of a long-span bridge were investigated. In addition to the static part in the modeling of tornado-like wind-induced loads, the motion-induced effects were modeled using the semi-empirical model with a two-dimensional (2-D) indicial response function. Both nonlinear wind-induced static analysis and linear aeroelastic analysis in the time domain were conducted based on a 3-D finite-element model to investigate the bridge performance under the most unfavorable tornado pattern considering wind-structure interactions. The results from the present study highlighted the important effects due to abovementioned tornado natures (i.e., nonuniform, intensive vertical wind-velocity and transient features) on the long-span bridge, and hence may facilitate more appropriate wind design of flexible horizontal structures in the tornado-prone areas.

• 보건의료산업학회지
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• 제10권4호
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• pp.153-165
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• 2016

Objectives : Recently, concern about the ubiquitous healthcare industry has increased worldwide. This study estimated the economic effects of the ubiquitous healthcare industry by Input-Output Analysis. Methods : In this study, $384^*384$ sector statistics of the Bank of Korea were used as the initial analysis tool, after adjustments, $9^*9$ sector statistics were used as the major research method for that industry. The main analysis tools of this study included a comparison of the backward and forward linkage effects, as well as the induced effects of the self-industry and other industries and the induced coefficients including products, value-added, employee's pay, sales surplus, and employment. Results : Based on the results of the analysis, the ubiquitous healthcare industry has great economic impacts which affects major macroeconomic factors including production and the backward linkage effect. Additionally, the induced effects of the self-industry, the ubiquitous healthcare industry, are significant compared to other industries in terms of production, employee's pay and operating surplus. Conclusions : The ubiquitous healthcare industry is a growth engines for national development. This paper offers alternatives for efficient industrial policies.