• 대한통합의학회지
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• 제8권4호
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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 Ecology and Environment
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• 제31권2호
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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.

• 대한통합의학회지
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• 제9권4호
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• pp.261-270
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• 2021

Purpose : The purpose of this study is to investigate the effects of sleep duration on stress and depression in college students. The results obtained will be used as a foundational framework for fostering a healthy sleep culture among college students and for formulating measures to improve the quality of their sleep. Ultimately, we intend to produce a publicity and educational material. Methods : For this study, a survey involving 100 college students was conducted, after which data based on a final total of 95 respondents were analyzed. The information on stress and depression were first analyzed in terms of general characteristics and then organized based on the data collected to investigate the effects of sleep duration on stress and depression. The participants were divided into the following groups: "less than 6 hours," "6 to 7 hours," and "7 to 8 hours." BEPSI-K (Brief encounter psychosocial instrument-Korean) was used for stress evaluation, while K-CESD-R (Korean version of center for epidemiologic studies depression scale-revised) was utilized for depression evaluation. Results : First, according to sleep duration, the BEPSI-K scores showed a statistically significant difference in each group (p<.01). In the post-hoc test, there was a difference among the "less than 6 hours" group, the "7 to 8 hours" group. A statistically significant difference was noted (p<.01). In addition, sleep duration had a statistically significant effect on the negative (-) direction of the BEPSI-K (p<.01). Second, the K-CESD-R score according to sleep duration showed a statistically significant difference in each group (p<.01). Notably, in the post-hoc test, the "less than 6 hours" group differed from the "6 to 7 hours" group, "7 to 8 hours" group. A statistically significant difference was noted (p<.01). In addition, sleep duration had a statistically significant effect on the negative (-) direction of the K-CESD-R (p<.01). Third, for the correlation between sleep duration and stress and depression, a negative (-) correlation was found between sleep duration and BEPSI-K and K-CESD-R. Meanwhile, a positive (+) correlation was found between BEPSI-K and K-CESD-R. Conclusion : Based on the findings of this study, the sleep duration of college students has an effect on stress and depression. The results of this study can be used as a foundational framework in formulating a plan for improving the quality of sleep of college students.

• Earthquakes and Structures
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• 제14권6호
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• pp.577-587
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• 2018

The quantitative assessment of the seismic collapse risk of a structure requires the usage of an optimal intensity measure (IM) which can adequately characterise the severity of the ground motion. Research suggests that the average spectral acceleration ($Sa_{avg}$) may be an efficient and sufficient alternate IM as compared to the more traditional first mode spectral acceleration, $Sa(T_1)$, particularly during seismic collapse risk estimation. This study primarily presents a comparative evaluation of the sufficiency of the average spectral acceleration with respect to ground motion duration, and secondarily assesses the impact of ground motion duration on collapse risk estimation. By assembling a suite of 100 historical ground motions, incremental dynamic analysis of 60 different inelastic single-degree-of-freedom (SDF) oscillators with varying periods and ductility capacities were analysed, and collapse risk estimates obtained. Linear regression models are used to comparatively quantify the sufficiency of $Sa_{avg}$ and $Sa(T_1)$ using four significant duration metrics. Results suggests that an improved sufficiency may exist for $Sa_{avg}$ when the period of the SDF system increases, particularly beyond 0.5, as compare to $Sa(T_1)$. In reference to the ground motion duration measures, results indicated that the sufficiency of $Sa_{avg}$ is more sensitive to significant duration definitions that consider almost the full wave train of an accelerogram ($SD_{a5-95}$ and $SD_{v5-95}$). In order to obtain a reduced variability of the collapse risk estimate, the 5-95% significant duration metric defined using the Arias integral ($SD_{a5-95}$) should be used for seismic collapse risk estimation in conjunction with $Sa_{avg}$.

• 대한감각통합치료학회지
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• 제3권1호
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• pp.1-11
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• 2005

Objective : The purpose of this study was to get the mean of duration of post-rotatory nystagmus test in normal children and to differentiate the duration of post-rotatory nystagmus test between normal children and children with pervasive developmental disorder. Method : 84 subjects were between 3 and 5 years of age and consisted of 64 normal children and 20 children with the pervasive developmental disorder. Analysis of the data was done by using t-test and ANOVA. Results : The results were as follows: 1. Range of duration of post-rotatory nyatagmus test in normal children was $5{\sim}22$second on left and $7{\sim}21$ second on right and the mean was 12.63 second on left and 12.59 second on right. 2. Range of duration of post-rotatory nystagmus test in children with the pervasive developmental disorder was $3{\sim}11$ second on both and the mean was 5.65 second on left and 5.60 second on right. 3. There was no significant difference between males and females with normal children in duration of post-rotatory nystagmus test. However, there was a significant difference of the mean duration between 3 and 5 years old normal group. 4. Children with pervasive developmental disorder significantly have relatively lower duration than the duration of post-rotatory nystagmus test of normal children. Conclusions : The results of the study showed significant difference between normal children and children with pervasive developmental disorder in duration of post-rotatory nystagmus test and suggest that they could be applied to the baseline of clinical therapy.

• 대한영양사협회학술지
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• 제27권2호
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• pp.113-123
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• 2021

This study aimed to examine the association between sleep duration, stress levels, and dietary behavior in adolescents. A survey was conducted on 453 students (227 male, 226 female) in high schools in the Chungbuk area. The participants were divided into groups based on daily sleep duration: group I (<5 hrs/d), group II (≥5 hrs/d and <6 hrs/d), group III (≥6 hrs/d and <7 hrs/d), and group IV (≥7 hrs/d). To measure the stress levels of participants, the survey had questions covering a variety of areas, including school life, family life, social relationships, and personal evaluation. To assess the dietary behaviors of participants, the survey included questions encompassing the Nutrition Quotient for Korean adolescents (NQ-A). Among female students, the sleep duration group IV had significantly lower total stress (P=0.022) and significantly lower stress in the personal evaluation area than the sleep duration group I (P=0.004). In the analysis of NQ-A, among female students, the sleep duration group IV showed significantly higher scores in balance (P=0.004), diversity (P=0.016), and total NQ-A score area (P=0.007) compared to other groups. There was a significant negative correlation between sleep duration and stress scores in total students (r=-0.24, P<0.001), while a significant positive correlation was seen between sleep duration and NQ-A scores in female students (r=0.16, P<0.05). To sum up, the longer the sleep duration, the lower the degree of stress, and the quality of meals which can be said to be a significant finding for high school students.

• Journal of Oral Medicine and Pain
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• 제14권1호
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• pp.9-17
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• 1989

The author has measured the duration of occlusal sounds during centric occlusal tapping in 30 patients with TMD and 30 normal subjects as controls, and then correlated the duration of occlusal sounds with CMI, amount of centric slide, midline deviation, habitual side of mastication, and presence of occlusal interference. The results were as follows 1. The duration of occlusal sounds during centric occlusal tapping were 36.26 msec in TMD patients and 22.8 msec in normal subjects (p<0.01). 2. The correlation between duration of occlusal sounds and CMI was significant (p<0.01). 3. The correlations between duration of occlusal sounds with amount of centric slide, midline deviation, habitual side of mastication, and presence of occlusal interference were not significant (p<0.05).

• Preventive Nutrition and Food Science
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• 제8권4호
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• pp.395-400
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• 2003

This study investigated the effect of sleep duration on food and nutrient intake among adult Koreans. The effects of sleep duration on dietary patterns was studied in 7,370 Korean adults, aged 20 and older, who participated in the 1998 Korean National Health and Nutrition Survey in which the 24 hour recall method was used to estimate dietary intake. Sleep duration data from individual subject were collected by interview as a part of a behavior survey. Analysis of variance and Duncan's multiple range test were used to test the differences in food and nutrition intake and sleep duration. Food intakes of the male subjects were not significantly different among three groups. However, there were significant differences observed in intakes of beverage and alcohol among female subjects among the three groups. There were no significant differences observed for nutrient intake by sleep duration for either gender. Unlike the observation from European and American studies, food and nutrient intake of Korean subjects, in general, were not greatly affected by duration of sleep. This result may suggest that dietary habits of Koreans, as affected by sleep, are quite different from those of Europeans & Americans.

• International Journal of Industrial Entomology and Biomaterials
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• 제19권2호
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• pp.215-219
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• 2009

The effect of mating duration and multiple use of male on fecundity and fertility was investigated in the hybrids of Silkworm, Bombyx mori L. One hour to five hours of mating duration did not affect egg laying (fecundity) significantly, while fertilization affected significantly. Below 50% fertility was noticed when mating duration was reduced to below two hours. Similarly multiple use of male caused significant reduction in fertility but not fecundity. Till fourth mating no significant reduction in fertility was observed, thereafter fertility reduced considerably.

• 한국콘텐츠학회논문지
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• 제15권12호
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• pp.314-325
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• 2015

본 연구는 청소년의 수면시간이 자살충동에 미치는 영향에 대한 성별 차이를 분석했다. 전국 규모의 자료를 사용해 이항 로지스틱 분석을 실시했으며, 주요 분석결과는 다음과 같다. 먼저, 평일 수면시간은 남학생 집단에서만 자살충동에 유의한 영향을 미쳤다. 평일 수면시간이 7시간 미만인 남학생이 자살충동을 경험할 가능성이 그렇지 않은 학생보다 약 1.9배 높았으며, 이 효과는 관련 변인을 통제했을 때도 유의했다. 여학생의 경우에는 평일 수면시간이 7시간 미만인 학생이 자살충동을 경험할 가능성이 약 1.3배 높았지만, 이 효과는 스트레스 변인 등을 통제했을 때 유의하지 않게 변했다. 한편, 주말 수면시간은 성별에 관계없이 자살충동에 유의한 영향을 미치지 못했다. 주말에는 일반적으로 등교부담이 없어 수면부족을 덜 경험하기 때문에 수면시간의 자살충동 효과가 유의하지 않게 나타난 것으로 보인다. 본 연구는 수면시간의 자살충동 효과에서 나타나는 평일과 주말 수면시간, 성별 집단에 따른 차이를 밝힘으로써 수면시간 연구에서 사회적 접근이 필요하다는 주장을 뒷받침했다.