• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.3
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• pp.261-275
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• 2011

To maintain the traffic flow during tunnel expansion, cars must be protected from falling rocks during excavation and to do so, a protector has to be installed inside the tunnel before beginning the excavation. In Korea, tunnel expansion by blasting rather than by mechanical excavation has been widely achieved. For this reason, a series of numerical analysis were performed to analyze the characteristics of impact load according to material behaviour of blasted rock by using Explicit FEA program. From the numerical results, it is found that the impact loads when rock is assumed as an elastic-plastic material appear to be only 7~12% compared with that when it is elastic.

• The KIPS Transactions:PartD
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• v.18D no.5
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• pp.329-338
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• 2011

Terminology recognition system which is a preceding research for text mining, information extraction, information retrieval, semantic web, and question-answering has been intensively studied in limited range of domains, especially in bio-medical domain. We propose a domain independent terminology recognition system based on machine learning method using dictionary, syntactic features, and Web search results, since the previous works revealed limitation on applying their approaches to general domain because their resources were domain specific. We achieved F-score 80.8 and 6.5% improvement after comparing the proposed approach with the related approach, C-value, which has been widely used and is based on local domain frequencies. In the second experiment with various combinations of unithood features, the method combined with NGD(Normalized Google Distance) showed the best performance of 81.8 on F-score. We applied three machine learning methods such as Logistic regression, C4.5, and SVMs, and got the best score from the decision tree method, C4.5.

• Journal of the Korean Data and Information Science Society
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• v.28 no.4
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• pp.863-874
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• 2017

Wins above replacement (WAR) is the most commonly used statistics of the many sabermetrics that measure baseball players' abilities. The advantage of a WAR is that it enables to compare performances of players even though they have different roles such as pitcher and hitter. However, WAR is difficult to obtain with common records. Thus, in this paper, we have calculated the sabermetrics variable based on Korean professional baseball records for the past three years (2014-2016). Using these variables, we suggest starting pitcher ability index that can replace WAR. Starting pitcher ability index was calculated by means of arithmetic mean, weighted average and principal component regression. Then, compared to the WAR, the most relevant method was selected, which would be useful to identify for the starting pitcher ability.

• 한국노년학
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• v.38 no.4
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• pp.945-962
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• 2018

This study was aimed to examine the association between resilience and mental health among individuals aged 65 and older. The number of the sample was 2,004 older people living in Chuncheon city. The dependent variables were measured with depression and mental well-being. Depression was measured by the Center for Epidemiological Studies-Depression(CES-D) 10 items. Mental well-being was measured by Korean version of the Mental Health Continuum-Short Form(K-MHC-SF). The independent variable, resilience, was measured with the Connor-Davidson Resilience Scale(CD-RISC). Adjusted for age, gender, region, education, living arrangement, religion, employment, income, and self-rated health, a logistic regression analysis result showed that resilience was negatively associated with depression among older adults. On the other hand, a multiple regression analysis result showed that resilience was positively associated with mental well-being among older adults. The study findings suggest that resilience can promote mental health in later life. Implications for older adults suffering from mental health problems are also discussed.

• The Korean Journal of Applied Statistics
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• v.36 no.6
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• pp.591-618
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• 2023

This paper evaluates the performance of various distribution assumptions in regression settings for estimating insurance loss. The gamma distribution is commonly used to handle the asymmetry property of loss distribution. However, recent studies highlight the significance of heavy-tailedness in loss distribution. Through an analysis of real home fire insurance data, we compare the effectiveness of different distribution assumptions in regression methods. Our findings show that the choice of parametric distributional assumption is crucial in determining premiums for various insurance products, including "excess of loss insurance" and "limit insurance". Additionally, we discuss practical considerations for applying our results in home fire insurance.

• Ecology and Resilient Infrastructure
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• v.11 no.2
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• pp.35-42
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• 2024

The aquatic ecosystem of rivers, where various biological groups inhabit, is influenced by suspended sediment. However, there is a lack of quantitative and objective methods and criteria for evaluating this impact. The purpose of this study is to analyze through experiments the effects of suspended sediment on Glyptotendipes tokunagai, a benthic invertebrate in rivers. Experiments were conducted to investigate the survival count of individuals exposed to varying suspended sediment concentrations (turbidity) and exposure durations. Various regression analysis methods were performed on the experimental results to propose a model for evaluating the impact of suspended sediment on Glyptotendipes tokunagai. The coefficient of determination (R-squared) of the proposed model was 0.903, indicating a high degree of fit. The findings of this study could serve as foundational data for assessing the influence of suspended sediment on various organisms inhabiting rivers.

• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.1
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• pp.12-20
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• 2020

Purpose: This study was designed to analyze the relationship between the presence and severity of depression and chewing problems (CPs) in a representative sample of the general population. Materials and Methods: Health surveys and examinations were conducted on a nationally representative sample (n = 8150) of Korean was conducted. CPs was determined by a simple survey response concerning "Do you feel uncomfortable about chewing your food because of problems with your mouth such as teeth, dentures and gums?" Depression was defined as individuals with a total score ≥ 10 on the Patient Health Questionnaire (PHQ)-9 survey. Data regarding demographics, socioeconomic history and comorbid health conditions were used to analyze adjusted logistic regression models. Results: In the Korean population, the prevalence of depression was significantly greater in individuals with CP (17.2%) than in those without CP (10.2%). On multivariate logistic regression analysis, the presence of depression was significantly associated with CPs (adjusted odd ratio [aOR]: 1.90, P < 0.001). The risk of CPs increased with increasing severity of depression as follows: severe depression (OR: 2.62, P < 0.001), moderately severe depression (OR: 2.19, P < 0.001). Conclusion: The presence of depression was significantly associated with CPs, especially in severely depressed individuals. Depression screening should be considered in treating CP patients.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.4
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• pp.46-55
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• 2023

This study investigated the public's awareness and purchase behavior of organic farming and environment-friendly agriculture products. This study also analyzed whether awareness affects environment-friendly agriculture products' consumption and price resistance and support for the revitalizing organic farming. This study derived environmental and public interst in organic farming, and a web survey was conducted for statistical analysis. As a result, it was found that the awareness of organic farming did not affect the consumption of environment-friendly agriculture products, but in case of high awareness is high, the resistance to prices is low. In addition, it was found that the stronger the public's awareness, the more positive the support for the expansion of organic agriculture and the willingness to purchase environment-friendly agriculture products. The results of this study are expected to be used as basic data for preparing measures to revitalize organic agriculture in the future.

• The Journal of the Korea Contents Association
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• v.20 no.9
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• pp.86-98
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• 2020

The purpose of the study is to examine the factors that influence on the Koreans' intergenerational communication. A survey was conducted with university students in their 20s, and the impacts of filial piety and indigenous cultural factors(confucianism and Chemyon) on intergenerational communication styles and intergeneral communication satisfaction were tested. Results of hierarchical regression analyses showed that politeness and confucianism had positive influence on intergenerational communication while deference and Chmyon had negative influence on intergenerational communication. The indigenous cultural variables increased total R2 significantly, proving the crucial impact of confucianism and Chemyon on the Koreans' intergenerational communication. Finally, male students perceived higher level of communicative satisfaction than female students in the intergenerational communication context.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1488-1494
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• 2011

In this paper, we propose an algorithm using linear regression model that forecasts the demand of heated water in winter. To supply heated water to apartments, stores and office buildings, Korea District Heating Corp.(KDHC) operates boilers including electric power generators. In order to operate facilities generating heated water economically, it is essential to forecast daily demand of heated water with accuracy. Analysis of history data of Kangnam Branch of KDHC in 2006 and 2007 reveals that heated water supply on previous day as well as temperature are the most important factors to forecast the daily demand of heated water. When calculated by the proposed regression model, mean absolute percentage error for the demand of heated water in winter of the year 2006 through 2009 does not exceed 3.87%.