• Journal of Family Resource Management and Policy Review
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• v.21 no.3
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• pp.141-159
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• 2017

The main purpose of this study is to investigate factors that influence sleep duration and sleep time poverty in terms of family characteristics, child characteristics, and time use. A series of data analyses were conducted on children's time use in two-parent families based on the 2013 Korean Children and Youth Panel Survey. One major finding is that children's sleep duration and the probability of having a sleep time poverty are related to their mothers' job classifications. The factors influencing the duration of sleep time and the sleep time poverty are similar in terms of family characteristics and children's time use. The mother's job classification, family income, number of younger siblings, number of older siblings, children's private tutoring hours, computer game hours, and TV hours are statistically significant factors affecting the duration of sleep time and the probability of having a sleep time poverty. However, the factor with greatest influence on sleep time duration is private tutoring hours and the factor most affecting sleep time poverty is computer game hours. The mother's job classification is a relatively powerful determinant for predicting her children's sleep duration and sleep time poverty.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.10 no.1
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• pp.50-57
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• 1999

A study to get the data of normal stop consonants production as preliminary study for cleft palate patients was performed. Normal Korean native 21 speakers were pronounced $VCV(V=/a/,C=/P/,/{P^1}/,/P^h/,/t/,/{t^1}/,/{t^h}/,/k/,/{k^1}/,/{k^h}/)$ syllables with natural speech rate and intensity. With intrapharyngeal pressure waveforms by pressure sensor in oropharyngeal cavity, amplitude and time duration of intrapharyngeal pressure were analyzed, and with acoustic waveforms and spectrograms, closure duration and VOT were analyzed. As results, the highest amplitude of intrapharyngeal pressure showed in alveolars and heavily aspirated consonants. Velars and unaspirated consonants were higher than bilabials and slightly aspirated ones each, in intrapharyngeal pressure. Bilabilas, alveolars and velars showed similar rise time of intrapharyngeal pressure build-up, but in decay time and total duration time, bilabials were slightly shorter than alveolars and velars, with no statistic significance. In the aspects of tensity, unaspirated consonants showed the longest rise time, heavily aspirated, the second, and slightly aspirated consonants, the shortest, which were also seen in decay time and total duration time. In closure duration, slightly aspirated consonants had the shortest closure duration, and the heavily aspirated ones, the second, and unaspirated consonants showed the longest. In VOT, heavily aspirated consonants showed the longest, slightly aspirated ones, the second and unaspirated ones showed the shortest.

• Journal of Environmental Science International
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• v.4 no.2
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• pp.117-120
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• 1995

The comparision of sunshine duration meter was carried out on the roof of Korea Meteorological Research Institude by comparing Pyrheliometer(Eppley NIP model) to sunshine duration meter(Reflection type) during from Nov. 8, 1989 to Feb. 19, 1990. In the observation Period, daily mean sunshine duration time difference of Jordan sunshine duration meter was recorded 0.47hour and Reflect sunshine duration meter was recorded 0.39hour. More than one hour time difference was observed 15 cases by Jordan sunshine duration meter and 11 cases by Reflect sunshine duration meter.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.4
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• pp.291-305
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• 2020

Purpose : The duration of speech segments reflects children's speech motor development. The purpose of this study was to determine whether segmental sound and word duration varies by age among preschool children. Methods : A total of 60 children aged 4~5 years participated in this study. Participants took the picture-naming test to produce single-word speech data. The duration of the consonant at the initial position of the word and the final position of the word, the voice onset time of plosive, the duration of the vowel following the initial consonant, and the duration of the word were measured. Results : As age increased, the duration of the initial consonant, the duration of the word, and the voice onset time decreased significantly. The main effects of age, manner of articulation, and place of articulation on the duration of the initial consonant were significant. The duration of consonants in the nasal sound and plosives and the duration of bilabial and alveolar sound differed significantly between groups. The main effects of age and vocal type on voice onset time were significant. The main effect of age on the duration of the consonant in the final position of word and on the duration of the vowel were not statistically significant. Conclusion : The results of this study showed that the duration of segmental sound and the word were associated with speech development between 4 and 5 years old. Accordingly, duration of the segmental sound and the word may serve as an acoustic cue as they reflect speech development and speech motor control maturity.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.2
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• pp.47-55
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• 2022

The objective of this study was to analyze the effect of the duration and time distribution of probability rainfall on farmland inundation for the paddy fields in the drainage improvement project site. In this study, eight drainage improvement project sites were selected for inundation modeling. Hourly rainfall data were collected, and 20- and 30-year frequency probability rainfalls were estimated for 14 different durations. Probability rainfalls were distributed using Intensity-Duration-Frequency (IDF) and Huff time distribution methods. Design floods were calculated for 48 hr and critical duration, and IDF time distribution and Huff time distribution were used for 48 hr duration and critical duration, respectively. Inundation modeling was carried out for each study district using 48 hr and critical duration rainfalls. The result showed that six of the eight districts had a larger flood discharge using the method of applying critical duration and Huff distribution. The results of inundation depth analysis showed similar trends to those of design flood calculations. However, the inundation durations showed different tendencies from the inundation depth. The IDF time distribution is a distribution in which most of the rainfall is concentrated at the beginning of rainfall, and the theoretical background is unclear. It is considered desirable to apply critical duration and Huff time distribution to agricultural production infrastructure design standards in consideration of uniformity with other design standards such as flood calculation standard guidelines.

• Journal of Engineering Education Research
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• v.17 no.1
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• pp.57-64
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• 2014

This study has a purpose mainly to analyze the team interaction change by the duration of time in the Capstone-Design activities according to MBTI Modes. Study objects are four students of Mechanical Engineering at School of Engineering in C University located in Daejeon, and the team interaction change was analyzed through IPA (Interaction Process Analysis) method. From the result, first, ESTP showed the change of increase in interaction by the time duration of initial, mid, late periods in 'social-emotional area: positive' and 'task area: question', and the change of decrease by the same time duration of periods in 'task area: solution'. Also, there was no change in 'social-emotional area: negative' because there was no interaction. Second, ESFJ showed the change of decrease in interaction by the time duration of initial, mid, late periods in 'social-emotional area: positive' and 'task area: question', and the change of increase by the same time duration of periods in 'task area: solution' and 'social-emotional area: negative'. Third, ISTJ showed the change of decrease in interaction by the time duration of initial, mid, late periods in 'social-emotional area: positive', 'task area: question' and 'social-emotional area: negative', and the change of increase by the same time duration of periods in 'task area: solution'. Fourth, ENFP showed the change of decrease by the time duration of initial, mid, late periods in 'social-emotional area: positive', 'task area: solution' and 'social-emotional area: negative', and the change of increase by the same time duration of periods in 'task area: question'.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.5 s.110
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• pp.503-513
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• 2006

The duration time of aircraft noise event is also an important factor for the evaluation of civil aircraft noise, which is considered as a notable characteristic of military aircraft noise. SEL is proved as a suitable noise metric for the measuring military aircraft noise of various flight pattern considering the duration time of noise event. This study reviews whether SEL is a suitable for measuring civil aircraft noise and study shows SEL is fairly compensating the duration time of civil aircraft noise event for the evaluation of aircraft noise. Noise metric for the evaluation aircraft noise based on SEL is more appropriate than based on $L_{MAX}$ for compensating duration time of noise event either military aircraft or civil aircraft. In this reason, current formula of WECPNL based on energy average of measured $L_{MAX}$ for the evaluation of aircraft noise impact in 'Test Method of Noise and Vibration of Korea' is recommended to be amended to formula of WECPNL based on energy average of measured SEL considering compensation of noise event duration time, if WECPNL is not based on measured EPNL, a metric compensating duration time.

• Journal of Korean Academic Society of Home Health Care Nursing
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• v.26 no.2
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• pp.180-188
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• 2019

Purpose: To investigate the duration of each nursing activity performed by home care nurses for non-cancer patients and the relationship between patients' palliative prognostic index (PPI) and duration of each nursing activity. Methods: Nursing activities performed for six non-cancer terminal patients were timed using a stopwatch, and 18 parameters were measured by visiting each patient thrice. The mean and standard deviations of duration for each category of nursing activities were computed. The relationship between category-specific duration of nursing activities and PPI was analyzed with Spearman's correlation and multiple regression analysis. Results: Among nursing activities, the highest greatest duration of time was spent on traffic time (11.91 min), followed by urinary catheter management (10.65 min) and insertion and management of nasogastric tube (9.03 min). In terms of nursing categories, after excluding movement time, the greatest duration of time was spent on excretion care (5.48 min), nutrition care (5.40 min), and medication (3.82 min). PPI correlated with hygiene care, excretion care, and patient and information management. Multiple regression analysis revealed that PPI increased with increasing duration of hygiene care. Conclusion: These study findings provide grounds for the increased nursing time of hygiene care for people reaching the end of life.

• Journal of Ecology and Environment
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• v.31 no.2
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• pp.139-146
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• 2008

To clarify the relationship between the timing and the duration of flowering among populations, plants, and individual flowers, the dates of flower budding, flowering and deflowering were monitored for ten woody species from March 1 to June 30, in 2005, 2006 and 2007, in temperate deciduous forests at three sites of Namsan, and individual plants from seven woody species were monitored from March 1 to May 31, in 2006. Total durations of flower budding, flowering, and deflowering varied among the plant species. Three durations of these phenological stages of Stephanandra incisa were the longest (74 days, 109 days, and 101 days, respectively), and those of Prunus serrulata var. spontanea were the shortest (7 days, 7 days, and 4 days, respectively). For each species, phenological durations varied among years but were similar among the study sites in the same year. There was no relationship between flowering time and flowering duration on the population level. On the plant level, the duration of flower budding was over 11 days in all specie; S. incisa had the longest duration (73.3 days), and that of Styrax japonica was long as well (29.0 days), while that of Prunus leveilleana was the shortest (11.3 days). The longer the mean flower budding duration, the greater the difference among the plants within a species. The flowering duration of for S. incisa was 92.2 days, while that of Forsythia koreana was 27.2 days. The flowering durations of all other species were $10{\sim}20$ days. The deflowering duration was 92.0 days in S. incisa and <15 days in all other species. Differences among the plants in deflowering duration were smaller than those of the other phenological stages. In the species that flowered in April, the correlation coefficient between the flowering duration and the first flowering date was negative and significant. However, in the species that flowered in May, the correlation between flowering duration and the first flowering date was not significant. For individual plants of all species except for S. alnifolia, the earlier the flowering time, the longer the flowering duration. Differences between flowering time and flowering duration across years were significant in six species.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.747-753
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• 2009

Planning the construction for a system of bored piles in building foundation engineering is (1) to predict the time duration required to complete all the bored piles with due consideration of relevant engineering factors and site constraints; then (2) to predict the total project time generally by aggregating the predicted working duration for construction of each bored pile. The duration for construction of an individual bored pile results from analyzing various working sequences and different activity duration (such as predrilling, excavation, steelfixing, air-lifting, and concreting, etc.), which is informed by experiences and site records of previous projects. However, determining the project duration for constructing many bored piles on one site is much more complicated than adding up the time duration for individual piles. In practice, project schedules are often found to be unrealistic and incorrect during the construction stage. This is because construction planning is not based on a exhaustive and comprehensive evaluation of site factors, such as site layout plan, site constraints, quality control, environmental control, safety control and logical relationships between different trades. In this paper, we identify those factors based on a foundation engineering site in Hong Kong with ninety-seven bored piles and address their effects on uncertainties in activity time and project time.