• Journal of Family Resource Management and Policy Review
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• v.6 no.1
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• pp.1-16
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• 2002

The purposes of this study were to explore amount of time use for house work, leisure and extracurricular lesson used by adolescents and to explain its influencing factors. Tobit model was used to analyze the factors of time use because amount of time use was a limited continuous variable. The results of this study were as follows: 1) Amount of time used for house work per day by adolescents was found to be 36min. for weekdays and 64 min. for holidays. Amount of time used for passive leisure per day by adolescents was found to be 203min. for weekdays and 375 min. for holidays. Amount of time used for active leisure per day by adolescents was found to be 74 min. for weekdays and 194 min. for holidays. Amount of time used for extracurricular lesson per day by adolescents was found to be 96min. for weekdays and 36 min. for holidays. 2) Time use for house work was found to be significantly influenced by education status, education level of mother, job status of mother for weekdays and gender, education level of mother, job status of mother, household income for holidays. Time use for passive leisure was found to be significantly influenced by education status, small children at home for weekdays and gender, education status for holidays. Time use for active leisure was found to be significantly influenced by gender, education status for holidays, while there was no influencing factors for weekdays. Finally, time use for extracurricular lesson was found to be significantly influenced by gender, education status, household income for weekdays, and age, education level of mother for holidays.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.344-355
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• 2012

This study was conducted to analyze on the operational time and productivities of logging operations in whole-tree logging operation system by tower-yarder and swing-yarder, and in cut-to-length logging operation system by excavator with grapple in order to establish the efficient logging operation system and to spread logging operation technique. In the analysis of operational time, in case of whole-tree logging operation system, the felling time was 46.6 sec/cycle by chain saw, the yarding time was 480.6 sec/cycle by tower-yarder, the yarding time was 287.4 sec/cycle by swing-yarder and the bucking time was 155.14 sec/cycle by chain saw. In case of the cut-to-length logging operation system, the felling and bucking time was 225.65 sec/cycle by chain saw, the cut-to-length extraction time was 4,972 sec/cycle by excavator with grapple, the branches and leaves extraction time was 3,143 sec/cycle by excavator with grapple. The forwarding time was 4,688 sec/cycle by wheel type mini-forwarder, the forwarding time was 2,118 sec/cycle by excavator with grapple and small forwarding vehicle. In the analysis of operational productivities, in case of whole-tree logging operation system, the average felling performance was $57.89m^3/day$ by chain saw, the average yarding performance was $20.3m^3/day$ by tower-yarder, $31.55m^3/day$ by swing-yarder respectively, the average bucking performance was $20.3m^3/day$ by chain saw. In case of the cut-to-length logging operation system, the average felling and bucking performance was $11.96m^3/day$ by chain saw, the average cut-to-length extraction performance was $34.75m^3/day$ by excavator with grapple, the average branches and leaves extraction performance was $37.66m^3/day$ by excavator with grapple, the average length of operation road construction was 73.8 m/day by excavator with grapple. The average forwarding performance by wheel type mini-forwarder and the average forwarding performance by excavator with grapple and small forwarding vehicle was $15.73m^3/day$ and $65.03m^3/day$, respectively.

• Sleep Medicine and Psychophysiology
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• v.3 no.2
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• pp.18-31
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• 1996

Jet-lag can be defined as the cumulative physiological and psychological effects of rapid air travel across multiple time zones. Many reports have suggested that age-related changes in sleep reflect fundamental changes in the circadian system and in significant declines in slow wave sleep. Jet lag is a dramatic situation in which the changes of the phase of circadian process and homeostatic process of sleep occur. Thus the authors evaluatead the changes of sleep-wake cycle from jet lag by age. Thirty-eight healthy travellers were studied for 3 days before and 7 days after jet-flights across seven to ten time zone. They were aged 19-70, They trareled eastbound, Seoul to North America (USA, Canada). Sleep onset time, wake-up time, sleep latency, awakening frequency on night sleep, awakening duration on night sleep, sleepiness at wake-up and nap length were evaluated. Our results suggest that by the 7 to 10 time zone shift, the old age group was significantly influenced in sleep-wake cycles. The date on which subjective physical condition was recovered was $6.23{\pm}83$ day after arrivals for old age group, while for young and middle age group, $4.46{\pm}1.50$ day and $4.83{\pm}1.52$ day, respectively. In old age group, sleep onset time was later than baselines and could not recover untill 7th day. But in other groups, the recovery was within 5th day. Nap dura fion was longer in old age group through jet lag than younger age group. In other parameters, there was no definite difference among three age groups. Our results suggested that the old age was significantly influenced by the disharmony between internal body clock and sleep-wake cycle needed at the travel site. Thus we proved that recovery ability from jet lag was age-dependent as well as travelling direction-dependent. To demonstrate more definite evidence, EEG monitoring and staging of sleep were funthun encouraged.

• Ocean and Polar Research
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• v.40 no.3
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• pp.99-114
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• 2018

In the present study, we assess the GloSea5 (Global Seasonal Forecasting System version 5) near-surface ocean current forecasts using globally observed surface drifter dataset. Annual mean surface current fields at 0-day forecast lead time are quite consistent with drifter-derived velocity fields, and low values of root mean square (RMS) errors distributes in global oceans, except for regions of high variability, such as the Antarctic Circumpolar Current, Kuroshio, and Gulf Stream. Moreover a comparison with the global high-resolution forecasting system, HYCOM (Hybrid Coordinate Ocean Model), signifies that GloSea5 performs well in terms of short-range surface-current forecasts. Predictions from 0-day to 4-week lead time are also validated for the global ocean and regions covering the main ocean basins. In general, the Indian Ocean and tropical regions yield relatively high RMS errors against all forecast lead times, whilst the Pacific and Atlantic Oceans show low values. RMS errors against forecast lead time ranging from 0-day to 4-week reveal the largest increase rate between 0-day and 1-week lead time in all regions. Correlation against forecast lead time also reveals similar results. In addition, a strong westward bias of about $0.2m\;s^{-1}$ is found along the Equator in the western Pacific on the initial forecast day, and it extends toward the Equator of the eastern Pacific as the lead time increases.

• Development and Reproduction
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• v.14 no.3
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• pp.207-214
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• 2010

The tremendous changes of uterine endometrium are observed during early pregnancy and protease and their inhibitors are involved in regulation of cell proliferation and remodeling of the tissues through remodeling the extracellular matrix (ECM). Some of the proteases and protease inhibitors have been suspected to a factor in endometrial changes but many parts of their expression profiles and the physiological roles are not uncovered. To evaluate the functional roles of them, in this study the expression profiles of proteases and protease inhibitors were analyzed using real-time quantitative PCR analysis. Mmp9 (matrix metalloproteinase 9) mRNA levels peaked on day 4 at the time of implantation. On the other hand, Ela2 (neutrophil elastase, NE) mRNA levels were peaked on day 2 of pregnancy. Its expression were decreased until day 4 of pregnancy but increased rapidly until day 7 of pregnancy and decreased again. NE inhibitor Slpi (secretory leukocyte protease inhibitor, SLPI) mRNA levels were related with the implantation stage and with the levels of Ela2. At the time of implantation the expression levels of Slpi mRNA were about 5 times higher than the Ela2 mRNA in the uterus. In the implantation stage embryos, Mmp9 specific mRNA was only detected at the blastocyst. On the other hand, the expression level of SLPI was higher than that of the Ela2 mRNA at blastocyst and 4.5 day p.c. embryos. Based on these results it is suggested that MMP9, SLPI, and NE have important physiological role in embryo implantation both in uterus and embryos.

• Korean Journal of Food Science and Technology
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• v.49 no.1
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• pp.56-62
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• 2017

The purpose of this study was to determine how seeding time changes the properties of soybean products meju and doenjang. Soybeans were seeded on the last day of May (5L), on the mid day of June (6M), and on the last day of June (6L), respectively. The 5L soybeans experienced a distinguishing hot and humid climate at the ripening stage, and these climate conditions resulted in smaller seed sizes. Fermentation briskly progressed in all doenjang until 120 days, and the 5L doenjang exhibited the lowest fermentation efficiency. The 5L soybeans showed the highest GABA, polyphenol contents, and ACE inhibitory activity, and the 6M soybeans showed the highest radical scavenging activity among the groups tested. In doenjang, the functional properties generally increased as the aging time approached the $120^{th}$ day, and the 6M doenjang showed the highest functional properties at the $120^{th}$ day. Therefore, 6M soybeans had the most appropriate characteristics when producing doenjang.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.506-510
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• 2005

As FPD technology is getting improved, there are a lot of issues on signal processing and analysis, and its relative importance has been increasing day by day. In particular, response time sad in the evaluation item of FPD has been measured by oscilloscope. In this paper, we propose an effective measurement method of response time in FPD. The proposed method is to calculate the rising/ falling time by using statistical techniques of histogram and analyzing an energy distribution. Ultimately, the method has proved the utility and reliability by comparison of oscilloscope

• Communications for Statistical Applications and Methods
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• v.7 no.2
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• pp.513-523
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• 2000

The X-12-ARIMA program was utilized on the analysis of the time series trend on 76 Korean industrial activities data in order to ensure that the trading day effect adjustment as well as the seasonal effect adjustment is needed to extract the fundamental trend-cycle factors from various economic time series data. The trading day effect is strongly correlated with the activity of production and shipping but not with the activity of inventory. Furthermore, the industrial activities were classified with respect to the sensitivity on the tranding day effect.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.4
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• pp.426-435
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• 2016

Objectives: The major objective of this study was to analyze stress response after a change to consecutive day shifts from day and night shifts in a motor assembly factory. Methods: Using a survey conducted by a labor union, we collected data on stress response index(SRI), lifestyle factors, work-family conflict and job stress before and after a shift system change. We analyzed the transition on the SRI among 222 workers. The cut-off point for the SRI was a T-score over 60. Results: The high risk stress response group was 20.3% of the population before the shift system change. After the shift system change it decreased to 11.3%. After the shift system change, social support improved, leisure time became more sufficient, work-family conflict declined, and sleep quality in the night shift week improved. In multivariable linear regression, among workers under 40 years old sleep quality on night shift, leisure time sufficiency, social support and work-family conflict contributed to the improvement of stress response. Among workers over 40, work-family conflict contributed to the improvement of stress response. Conclusions: The change to consecutive day shifts improved stress response and mediated with improved nighttime sleep, decreased work-family conflict, increased leisure time and improved work-family conflict.

• International Journal of Human Ecology
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• v.3 no.1
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• pp.127-136
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• 2002

According to the Labor Standard Law in Japan which was enacted after World War II in 1947, all work hours for adult men, women, and youth were set at a maximum of eight hours per day and forty-eight hours per week. In other words, a six-day work week, with only one-day off, was set. Now we are in the full five-day and two-day off school system. The five-day school week influences on our home life. Students are highly enthused by the new system, in looking forward to their personal time they now have to play with friends, to relax, or just watch TV. To implement this new five-day school system positively and effectively, we should see the point at issue related to the two-day off system from a different angle, which suggests that we should see far ahead into the future.