• Journal of Environmental Science International
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• v.18 no.4
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• pp.369-374
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• 2009

To examine the trend on the flowering time in some weather flora including Prunus serrulata var. spontanea, Cosmos bipinnatus, and Robinia pseudo-acacia in Busan, the changes in time series and rate of flowering time of plants were analyzed using the method of time series analysis. According to the correlation between the flowering time and the temperature, changing pattern of flowering time was very similar to the pattern of the temperature, and change rate was gradually risen up as time goes on. Especially, the change rate of flowering time in C. bipinnatus was 0.487 day/year and showed the highest value. In flowering date in 2007, the difference was one day between measurement value and prediction value in C. bipinnatus and R. pseudo-acacia, whereas the difference was 8 days in P. mume showing great difference compared to other plants. Flowering time was highly related with temperature of February and March in the weather flora except for P. mume, R. pseudo-acacia and C. bipinnatus. In most plants, flowering time was highly related with a daily average temperature. However, the correlation between flowering time and a daily minimum temperature was the highest in Rhododendron mucronulatum and P. persica, otherwise the correlation between flowering time and a daily maximum temperature was the highest in Pyrus sp.

• The Journal of Information Systems
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• v.29 no.4
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• pp.1-24
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• 2020

Purpose An increase in the number of fitness apps across the world is a testament to the growing interest in health. As focus on medical services shifted from treatment to prevention, this type of app plays an essential role in promoting one's health and exercise management. Yet little has been known about practical effects of fitness apps in existing literature thus this study searches for factors that affect daily use of fitness apps and examine the relationship between app usage and exercise patterns. Design/methodology/approach This study surveyed people who used Cashwalk, the pedometer app for a minimum of a week to analyze reasons why they used the app. Particpants' exercise patterns were also recorded. By examining survey results of fitness app users and developing a research model based on the Customer Value Theory, this study provides real-life factors to the fitness and smart health care industry that will adopt a proactive lifestyle pattern. Findings Empirical analysis proved properties such as the complexity of fitness apps, monetary rewards, exercise monitoring and the enjoyment of using fitness apps contribute to using fitness apps on a daily basis. Furthermore, more daily use of fitness apps was shown to have a greater impact on exercise. This study also confirmed that social comparison does not affect the daily use of fitness apps and the amount of exercise, and the habitual walking was proved to directly affect the amount of exercise.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.3
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• pp.252-261
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• 2018

This study was conducted to develop a method to generate daily maximum and minimum temperatures using monthly data. We analyzed 30-year daily weather data of the 23 meteorological stations in South Korea and elucidated the parameters for predicting annual trend (center value ($\hat{U}$), amplitude (C), deviation (T)) and daily fluctuation (A, B) of daily maximum and minimum temperature. We use national average values for C, T, A and B parameters, but the center value is derived from the annual average data on each stations. First, daily weather data were generated according to the occurrence of rainfall, then calibrated using monthly data, and finally, daily maximum and minimum daily temperatures were generated. With this method, we could generate daily weather data with more than 95% similar distribution to recorded data for all 23 stations. In addition, this method was able to generate Growing Degree Day(GDD) similar to the past data, and it could be applied to areas not subject to survey. This method is useful for generating daily data in case of having monthly data such as climate change scenarios.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.4
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• pp.37-46
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• 2016

This study is to estimate COMS (Communication, Ocean and Meteorological Satellite) daily land surface temperature (LST) of Korea Peninsula from 15 minutes interval COMS LST (COMS LST-15) satellite data. Using daily observed LST data of Automated Agriculture Observing System (AAOS) 11 stations from January 2013 to May 2015, the COMS daily LST was compared and validated. For the representative time for daily mean LST value from COMS LST-15, the time of 23 : 45 and 0:00 showed minimum deviations with AAOS daily LST. The time zone from 23 : 45 to 1:15 and from 7 : 30 to 9 : 45 showed high determination coefficient (R2) of 0.88 and 0.90 respectively. The daily COMS LST by averaging COMS LST-15 of the day showed R2 of 0.83. From the 5 cases of results, the COMS daily LST could be extracted from the average LST by using 15 minutes data from 7 : 30 to 9 : 45.

• Journal of the Korean Operations Research and Management Science Society
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• v.41 no.3
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• pp.59-74
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• 2016

Electricity sales are directly measured from individual consumers, which could minimize the time gap between data collection and public announcement. Furthermore, industrial electricity sales are highly linked with production and output. Therefore, industrial electricity consumption can be used to track production and output in real time. By using the high-frequency data of industrial electricity sales, this study develops the daily electricity business index (DEBI) to capture the daily economic status. The steps used to formulate DEBI are as follows: (1)selection of the explanatory variables and period, (2) amendment of the seasonal adjustment to eliminate daily temperature and effective day effects, (3) estimation of the weighted value via variables by using PCA, (4) calculation of DEBI and commencement of validation tests. Our empirical analysis and the Hodrick-Prescott filter analysis show that DEBI is highly related to existing economic indices.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.4
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• pp.287-293
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• 2003

This study examined the temperature-dependent regression model of energy consumption based on various measuring period. The methodology employed was to construct temperature-dependent linear regression model of daily energy consumption from one day to three months data-sets and to compare the annual heating energy consumption predicted by these models with actual annual heating energy consumption. Heating energy consumption from a building in Daejon was examined experimentally. From the results, predicted value based on one day experimental data can have error over 100%. But predicted value based on one week experimental data showed error over 30%. And predicted value based on over three months experimental data provides accurate prediction within 6% but it will be required very expensive.

• Human Ecology Research
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• v.52 no.3
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• pp.243-253
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• 2014

This qualitative case study examined the experience of middle-aged homemakers with buying and wearing clothes. Clothing benefits and clothing purchase types were observed in the homemakers' daily clothing-related behavior. This study aims to understand clothing consumption values in light of clothing benefits and to determine purchasing methods, purchasing mental states, and personal characteristics according to the clothing purchase types of middle-aged homemakers. The participants of this study were four full-time homemakers and four homemakers with a job outside the home, all in middle age. This study was conducted through in-depth interviews based on an unstructured questionnaire, and the data were collected from January 2010 to October 2010. The results were as follows: first, the clothing benefits were identified as a social stereotype, aesthetic taste, economy, wearing situation, and age perception. The most important clothing consumption values to the middle-aged homemakers based on the observed clothing benefits were, in order: social value, emotional value, epistemic value, functional value, and conditional value. Second, the type of clothing purchase was observed to be planned buying, followed by impulse buying, and compensatory buying. Even when a homemaker planned to shop regularly, when they were exposed to an attractive retailer promotion, they seized on the opportunity on impulse or made a compensatory purchase to divert oneself. Even though homemakers prefer primarily impulse buying, when they went shopping for clothing with their mother-in-law or husband, they made planned purchase also.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.1
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• pp.111-120
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• 2018

The purpose of this study was to develop a ridge regression (RR) model to estimate BOD and TP load using runoff weighted value. The concept of runoff weighted value, based on distributed curve-number (CN), was introduced to reflect the impact of land covers on runoff. The estimated runoff depths by distributed CN were closer to the observed values than those by area weighted mean CN. The RR is a technique used when the data suffers from multicollinearity. The RR model was developed for five flow duration intervals with the independent variables of daily runoff discharge of seven land covers and dependent variables of daily pollutant load. The RR model was applied to Heuk river watershed, a subwatershed of the Han river watershed. The variance inflation factors of the RR model decreased to the value less than 10. The RR model showed a good performance with Nash-Sutcliffe efficiency (NSE) of 0.73 and 0.87, and Pearson correlation coefficient of 0.88 and 0.93 for BOD and TP, respectively. The results suggest that the methods used in the study can be applied to estimate pollutant load of different land cover watersheds using limited data.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.4
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• pp.29-35
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• 2019

PURPOSE: The aim of this study was to provide the standard value of the Five Times Sit to Stand Test (FTSST) measurement on the daily life independence of the elderly in Korea and examine the effects of this test on their daily lives. METHODS: This study was conducted on elderly people over 65 years of age living in Gyeongsangbuk-do, Korea. FTSST was performed while sitting position on a chair. The subjects were classified into independent and dependent living groups according to their lifestyle, and their influence was then examined through logistic regression analysis. To determine the usefulness and cut-off value of the FTSST, the analysis was performed using the ROC curve. RESULTS: The elderly were more likely to live in a group rather than independently as the FTSST time increased (p<.05) (OR=1.098). The area of the lower part of the ROC curve was .707, and as the FTSST increased, a subject was more likely to live in a group rather than independently (p<.05). The cut-off value was assigned to the point where both the specificity and sensitivity were at the coordinates. The sensitivity and specificity were .626 and .753, respectively at 15.62 seconds. CONCLUSION: The elderly in Korea are more likely to live a group-dependent lifestyle than live independently; the likelihood of this outcome is increased further for every additional second beyond 15.62 seconds. The loss of independence of daily life could be predicted based on the status of a subject's lower leg strength using the FTSST.

• Journal of Environmental Health Sciences
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• v.48 no.1
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• pp.52-58
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• 2022

Background: Few studies have evaluated the exposure to phthalates via inhalation of floor dust in children's living areas. Objectives: This study evaluated the concentration and exposure level of phthalates emitted from indoor floor dust in children's living areas. Methods: This study utilized the results of a survey conducted by the Ministry of Environment in 2019. Indoor dust was collected from 150 households with children aged 3~7 and 67 daycare centers or local children's centers by using vacuum cleaners. It was analyzed by gas chromatography mass spectrometry. Six types of phthalates were analyzed: Bis (2-ethylhexyl) phthalate (DEHP), Dibutyl phthalate (DBP), Benzyl butyl phthalate (BBP), Di-N-octyl phthalate (DNOP), Diisononyl phthalate (DINP), Di -isodecyl phthalate (DIDP). Results: The medians of DEHP concentrations were 1,028 and 1,937 mg/kg in homes and daycare centers, respectively. The median and maximum values of daily intake were calculated by applying the median and 95th percentile values (the upper 5% of the total concentration) in dust measured in the homes. The DEHP median value was 1.6 ㎍/kg/bw/day, and a maximum A value of 7.8 ㎍/kg/bw/day was calculated. When the childcare center values were applied, the median daily intake of DEHP was 3.1 ㎍/kg/bw/day and the maximum value was 29.2 ㎍/kg/bw/day. As a result of calculating the daily intake by integrating the values of home and childcare facilities, the median and maximum values of daily intake were 1.9 and 10.9 ㎍/kg/bw/day, respectively. Conclusions: This study derives phthalate concentrations among the floor dust in homes and childcare facilities where children mainly spend time, and suggests their intake of phthalates through this. In particular, it was newly suggested that the phthalate concentrations in homes and childcare facilities are different, resulting in differences in intake.