• Journal of Distribution Science
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• v.13 no.12
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• pp.33-40
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• 2015

Purpose - Given an increase in the consumption of plums, prices have fluctuated in an unstable manner, making it difficult for farmhouses to sell the product. This study intends to provide information on the cultivation and sale of plums to consumers, thus enabling producers to utilize relevant information to analyze the types of plums that are preferred and consumed by users. Research design, data, and methodology - In this study, a survey was conducted on plum consumption by a consumer panel established and operated by the Rural Development Administration in December 2009. The objective was to identify the purchasing awareness of plums and to analyze panel data from 2010 to 2013 using a linear regression model, a Tobit model, and a panel regression model to derive the purchase characteristics. Results - The outcome of the survey on plums is as follows. Plums are purchased because they are good for the health (90.6%), which means that most customers purchase plums for their health benefits. When plums are in season, the purchase rate is 94.8%, indicating that most plums are purchased when they are in season and that selling plums when they are out of season is difficult. Therefore, we sell most plums in the correct season, and the rest of the plums need to be processed and then sent to markets. The strongest reason for not purchasing plums is that they are difficult to process for consumption (63.1%), followed by the reason that the fruit is unfamiliar (15.5%). Regarding solutions for increasing the consumption of plums, the answers were as follows: distribute a recipe for plums (36.9%), advertise its effect through TV or the press (31.1%), and develop various processed products (15.6%). When customers decide to pick out plums, the major considerations were freshness (4.43), safe to eat (4.16), price (3.96), size (3.87), brand (3.28), and discount event (2.62). Freshness is important for decision making and safe to eat was more important than price because plums are washed and processed into plum jam. According to the results of the linear regression model, a higher family income results in a higher purchasing amount. However, the amount of plums purchased by a person was reduced if his or her income increased. Compared with individuals who used other purchasing agents on weekdays, those who used the traditional market turned out to purchase a higher amount of plums on the weekdays. Conclusions - Considering that numerous people purchase plums for their health benefits, promoting the consumption of plums is anticipated as being successful if they can be produced safely for consumption and for inclusion in recipes and various processed foods, and to promote eco-friendly agricultural practices.

• Journal of the Korea Society for Simulation
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• v.23 no.4
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• pp.189-195
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• 2014

In this paper, we conducted a study on place-free and time-free cloud computing (CC) adoption decision-making model. Panel survey data which is collected from 65 people and CART (classification and regression tree) which is one of data mining approaches are used to construct decision-making model. In this modeling, there are 2 steps: In the first step, significant questions (variables) are selected. After that, the CART decision-making model is constructed using the selected variables. In the variable selection stage, the 25 questions are reduced to 5 ones. The benefits of question reduction are quick response from respondent and reducing model-construction time.

• Journal of Environmental Science International
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• v.22 no.2
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• pp.235-242
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• 2013

The purpose of this article is analyzing the impacts of climate change on winter chinese cabbage yield in Korea, with employing a panel data regression model. Our results show that there is a negative impacts of high temperature and precipitation amount on winter chinese cabbage yields. Especially high temperature and rainfall in September cause serious damage to winter chinese cabbage yield. According to the reduction schedule on greenhouse gas emission(RCP 4.5 scenario.), winter chinese cabbage yield would be 7.7% lower than it is, for reasons of high temperature and rainfall damages by the end of 21st century.

• Journal of Environmental Science International
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• v.21 no.12
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• pp.1503-1510
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• 2012

The purpose of this article is analyzing the impacts of climate change on red pepper yield in Korea, with employing a panel data regression model. Our results show that there is a negative impacts of high temperature and precipitation amount on red pepper yields. Especially high temperature and rainfall in July cause serious damage to red pepper yield. According to the reduction schedule on greenhouse gas emission(RCP 8.5 scenario.), red pepper yield would be 25.4% lower than it is, for reasons of high temperature and rainfall damages by the end of 21st century.

• Current Photovoltaic Research
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• v.10 no.1
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• pp.6-15
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• 2022

Climate change is among the most important issues facing mankind in modern society. However, global PV energy expansion has been driven mainly by OECD countries. We investigate the determinants of PV energy growth by panel data of selected OECD countries from 1991 to 2018. We investigate four categories of driving factors: socioeconomic, technological, country specific, and policy factors. The test results support that PV capacity growth is significantly driven by technology development and multidimensional environment policy factors. Socioeconomic factors such as CO₂, GDP, and electricity price are statistically significant on the growth of PV energy, too. Whereas, country-specific solar potential factor is the least related. As most of the socioeconomic factors are exogenous, we need to focus more on PV technology development and policy measures.

• Journal of Korea Entertainment Industry Association
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• v.14 no.2
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• pp.213-224
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• 2020

Purpose: This study is a descriptive and secondary analytical study that uses panel data to identify the factors of medication adherence to improve life care of hypertensive patients. Methods: The subjects of this study were 2,484 patients who were taking medication after hypertension using Korea Medical Panel 2015 data (β-version 1.0). Data analysis was performed using Chi-Square, Scheffe's test, and logistic regression using SPSS/win 22.0. Results: The level of medication adherence in patients with hypertension was 94.2%. The factors of medication adherence were gender and age in Model I of demographic factors, and the presence of disability, smoking, and drinking in Model II. Model III, which added drug use factors, was identified as drinking, drug duration, side effects, drug satisfaction, and payment of drug costs. Conclusion: In order to improve life care for hypertension patients, education and interventions on the importance of take medication and side effects of medications and how to take them will be needed in the early stages of diagnosis.

• Journal of Preventive Medicine and Public Health
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• v.56 no.6
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• pp.515-522
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• 2023

Objectives: The pandemic caused by coronavirus disease 2019 (COVID-19) has exerted an unprecedented impact on the health of populations worldwide. However, the adverse health consequences of the pandemic in terms of infection and mortality rates have varied across countries. In this study, we investigate whether COVID-19 mortality rates across a group of developed nations are associated with characteristics of their healthcare systems, beyond the differential policy responses in those countries. Methods: To achieve the study objective, we distinguished healthcare systems based on the extent of healthcare decommodification. Using available daily data from 2020, 2021, and 2022, we applied quantile regression with non-additive fixed effects to estimate mortality rates across quantiles. Our analysis began prior to vaccine development (in 2020) and continued after the vaccines were introduced (throughout 2021 and part of 2022). Results: The findings indicate that higher testing rates, coupled with more stringent containment and public health measures, had a significant negative impact on the death rate in both pre-vaccination and post-vaccination models. The data from the post-vaccination model demonstrate that higher vaccination rates were associated with significant decreases in fatalities. Additionally, our research indicates that countries with healthcare systems characterized by high and medium levels of decommodification experienced lower mortality rates than those with healthcare systems involving low decommodification. Conclusions: The results of this study indicate that stronger public health infrastructure and more inclusive social protections have mitigated the severity of the pandemic's adverse health impacts, more so than emergency containment measures and social restrictions.

• Journal of Korean Society of Transportation
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• v.36 no.2
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• pp.141-154
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• 2018

In order to meet the ever-increasing demand for international air travel, several plans are underway to open new airports and expand existing provincial airports. However, existing air demand forecasts have been based on the total air demand in Korea or the air demand among major cities. There is not much forecast of regional air demand considering local characteristics. In this study, the outbound air travel demand in the southeastern region of Korea was analyzed and the fixed-effects model using panel data was proposed as an optimal model that can reflect the inherent characteristics of metropolitan areas which are difficult to observe in reality. The results of model validation show that panel data analysis effectively addresses the spurious regression and unobserved heterogeneity that are difficult to handle in a model using only a few macroeconomic indicators with time series characteristics. Various statistical validation and conformance tests suggest that the fixed-effects model proposed in this study is superior to other econometric models in predicting demand for international demand in the southeastern region.

• Physical Therapy Rehabilitation Science
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• v.12 no.2
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• pp.80-91
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• 2023

Objective: The purpose of this study is to identify factors that affect the incidence of hypertension using logistic regression and decision tree analysis, and to build and compare predictive models. Design: Secondary data analysis study Methods: We analyzed 9,859 subjects from the Korean health panel annual 2019 data provided by the Korea Institute for Health and Social Affairs and National Health Insurance Service. Frequency analysis, chi-square test, binary logistic regression, and decision tree analysis were performed on the data. Results: In logistic regression analysis, those who were 60 years of age or older (Odds ratio, OR=68.801, p<0.001), those who were divorced/widowhood/separated (OR=1.377, p<0.001), those who graduated from middle school or younger (OR=1, reference), those who did not walk at all (OR=1, reference), those who were obese (OR=5.109, p<0.001), and those who had poor subjective health status (OR=2.163, p<0.001) were more likely to develop hypertension. In the decision tree, those over 60 years of age, overweight or obese, and those who graduated from middle school or younger had the highest probability of developing hypertension at 83.3%. Logistic regression analysis showed a specificity of 85.3% and sensitivity of 47.9%; while decision tree analysis showed a specificity of 81.9% and sensitivity of 52.9%. In classification accuracy, logistic regression and decision tree analysis showed 73.6% and 72.6% prediction, respectively. Conclusions: Both logistic regression and decision tree analysis were adequate to explain the predictive model. It is thought that both analysis methods can be used as useful data for constructing a predictive model for hypertension.

• Journal of Korea Trade
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• v.25 no.4
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• pp.146-163
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• 2021

Purpose - This paper examines China's impact on Korea's ICT exports considering the direct competition channel, the production shift channel, and the indirect demand channel at once. This paper also takes China's economic rebalancing into account and discusses whether it makes any differences in the effect of the three channels. Design/methodology - To quantify the effect of the three channels, I constructed a linear panel regression model and estimated it with various estimation methods including the system GMM. China's exports toward the same destination as Korea's exports, Korea's exports toward China, and the third countries' exports toward China respectively reflect the three channels. China's GVC indicators are included as well to evaluate the effect of further China's economic rebalancing. Since the present paper has a greater interest in the effect of China rather than the determinant of bilateral trade, a (fixed effect) panel model becomes more appropriate than the gravity model because timeinvariant variables in the gravity model, such as the distance and the language, are eliminated during the estimation process. Findings - The estimation results indicate that Chinese ICT exports are complementary to Korea's ICT exports in general. However, when markets are considered in subgroups, China's ICT exports could have a negative effect in the long run, especially for SITC75 and SITC76 markets, implying a possible competitive threat of China. The production shift effect turns significant during China's economic rebalancing in the markets for the advanced economies and the SITC76 product. China's indirect demand channel is also in effect significantly for the advanced economy and SITC75 commodities during China's economic rebalancing periods. In addition, this paper shows that China's transition toward upstream in the global value chain could have a positive impact on Korea's ICT exports, especially at the Asian market. Originality/value - The contribution of this paper is threefold. First, it focuses on the ICT industry for which Korea increasingly depends on China and China becomes a global hub of the GVC. Second, this paper quantitatively studies three channels in a model in contrast to the literature which mostly examines those channels separately and pays less attention to the GVC aspect. Third, by utilizing relatively recent data from the period of 2001-2017, this paper discusses whether China's economic rebalancing affects the three channels.