• Journal of the Korean Society of Safety
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• v.15 no.4
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• pp.35-40
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• 2000

The influence of cyclic loading history on the creep behavior of the 30 vol% hot-pressed $SiC_f/Si_3N_4copmposite was experimentally investigated at $1200^{\circ}C$. The duration of loading/unloading had great effects on the creep behaviors. The short term duration cyclic loading history test results showed significant reduction in the primary and steady-state creep rates. For example, 300sec loading/300sec unloading history resulted in 70% lower steady-state creep rate than that of the continuous loading. However the long term duration cyclic loading history test results showed little change in creep rates compared to those of the continuous one. The reason for the significant change in the short term duration cycles was estimated due to the change in the stress redistribution between the fiber and matrix during the creep recovery in the primary stage.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.162-165
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• 1989

This paper describes an algorithm of P-wave detection by significant point extraction method with digital differentiation. P-waves are detected by pattern matching algorithm with significant points. By means of defecting onset and offset points of P-waves, this algorithm can measure the PR intervals exactly which is important to diagnosis the atrial arrhythmia. Because P-wave duration is changed according to heart-rates, we calculate the R-R interval prior to the determination of P-wave duration threshold values in order to actively adapt to the change of P duration The results obtained from the proposed algorithm have defected successfully P-wave almost more than 90%.

• Food Science of Animal Resources
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• v.21 no.3
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• pp.272-277
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• 2001

Electrocardiograms in rats fed diets with boiled eggs for 30 days was investigated. Amplitudes of P,Q and R waves were not significant differences among treatment groups. Amplitude of S wave in rats fed the diet with 95% boiled eggs was significantly tended to be increased compared with other groups(P<0.05). Amplitude of T wave in the rats fed the diet with 0% boiled eggs showed the highest values, and there were significant difference among treatment groups fed diets with 0% boiled eggs, 25% and 95% boiled eggs (P<0.05). Durations of P and PQ(PR) waves were high in the rats fed diets with 25% and 50% boiled eggs (P<0.05). Duration of QRS complex showed low in the rats fed diet 0% boiled eggs but not significant difference among treatment groups. Duration of QT was high in the rats fed diet with 0% boiled eggs(P<0.05). This result is assumed that electrocardiograms in the rats is not changed to intake the boiled eggs.

• Journal of Preventive Medicine and Public Health
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• v.39 no.1
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• pp.74-80
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• 2006

Objectives: The purpose of this study is to examine the factors affecting the rate and duration of breastfeeding. Methods: We analyzed the data from the year 2000 Korea National Fertility Survey that was collected through direct interviews. In particular, the mothers who delivered their last child and the child was under 1 year of age from January 1998 to June 2000 (N=1,066) were analyzed via a logistic model to assess the factors affecting the breastfeeding rate. Among the study subjects, those who had initiated breastfeeding (N=740) were analyzed through Cox's proportional hazard model to evaluate the factors affecting the duration of breastfeeding. Results: The multivariate logistic model showed that the delivery type and the baby's birth-weight have a statistically significant influence on the breastfeeding rate. Women who delivered their babies through Cesarean section were less likely than others to breastfeed. In contrast, the women whose babies weighed 2.5Kg or more were more likely than others to breastfeed. The results obtained from the survival analysis are as follows: the higher the mother's education level, the shorter is the breastfeeding duration. The mother's work status played a significant role in the early termination of breastfeeding. Women aged 35 or older showed a longer breastfeeding duration than the younger age groups, whereas the maternal age was not a significant factor in affecting whether or not a mother would breastfeed. Conclusions: Reducing the cases of operative delivery (Cesarean section) and low weight births, enlightening young and highly educated women on breastfeeding and improving the environment for breastfeeding on the job are important strategies to encourage women to breastfeed.

• Speech Sciences
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• v.13 no.3
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• pp.19-33
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• 2006

This study explores whether Russian, known to have a process of syllable-final devoicing, reveals differences in vowel duration as a function of the underlying voicing of the coda stop. This paper also examines whether non-native speakers of Russian and English learn typical L2 values in vowel duration. The results indicate that vowels in Russian have a slightly longer mean duration before a voiced stop than before a voiceless stop (a mean difference of 9.52 ms), but in most cases the differences did not exhibit statistical significance. In English the mean difference was 60.05 ms, and the differences were in most cases statistically significant. All native Russian speakers of English produced larger absolute differences in vowel duration for English than for Russian, and all native English speakers of Russian produced smaller absolute differences for Russian than for English. More experienced learners seemed to achieve more native-like values of vowel duration than less experienced learners did, suggesting that learning occurs gradually as the learners gain more experience with the L2.

• Phonetics and Speech Sciences
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• v.2 no.2
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• pp.79-83
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• 2010

As bolus enters the pharynx during the swallow, laryngeal closure takes place by approximating the epiglottis to the arytenoid Laryngeal Closure Duration(LCD) is the duration of contact between the arytenoids and the epiglottis from the first contact to the last(Logemann et al, 2000). Epiglottic inversion continues pharyngeal swallow stage is completed in order to protect the airway. The purpose of this study is to measure layrngeal closure duration (LCD) in three groups of subjects: a) 10 stroke patients who aspirate before and during the swallow(aspirators), b) 10 stroke patients who do not aspirate during the swallow c)10 normal control subjects. Means and standard deviation of LCD was analyzed in both 5ml and 10 ml thin liquids using 100msec timer in videoflouroscopic swallowing examination. The mean for each group was 0.15 seconds shorter from aspirators to control group. There was a significant difference between aspirators and normal subjects for laryngeal closure duration during the swallow. Laryngeal closure duration after a stroke lead to aspiration. However, only one of this temporal problem may not be enough to aspiration.

• Phonetics and Speech Sciences
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• v.4 no.3
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• pp.85-92
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• 2012

It is a well-known phenomenon that vowel duration in English is generally longer before a voiced stop than a voiceless one. Past research has postulated that the closure duration of the voiceless stop is generally longer than that of the voiced stop and that the duration of a preceding vowel is determined complementarily by the closure duration of the stop. To shed further light on the phenomenon, this study examined fourteen native speakers of American English who read the monosyllabic words [bVC] (V = [i, ɪ, eɪ, ɛ, æ, ʌ, ɑ], C = [t, d]). First, we found that mean vowel duration was 38 ms longer before the voiced stop than the voiceless (mean duration ratio = 1.24). Second, mean closure duration of the voiced stop was only shorter by 5 ms compared to the voiceless stop (mean duration ratio = 0.97). Therefore, for our subjects, vowel duration was not determined complementarily by the closure duration of the following stop. Third, vowels with longer inherent durations (viz., tense, diphthong, and low vowels) tended to show larger duration ratios in the voiced and voiceless contexts than the vowels with shorter durations (viz., lax vowels). This indicates that the lengthening of inherently shorter vowels before a voiced stop is limited in order to avoid overlapping with longer vowels in the duration range. Fourth, there was no significant gender difference in vowel duration ratios in the contexts of voiced and voiceless stops. Finally, considerable individual differences were found in the vowel and consonant duration ratios.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.7 no.1
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• pp.51-66
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• 2001

Objective: The purpose of study was to compare physical therapy duration in relation tohealth care organization system in patients with low back pain. Subjects: Subjects of this study were 759 patients who are receiving physical therapy at 56 health care organization. Methods: Data were collected by questionnaire that had been completed by patients and physical therapist for two months. Physical therapy procedures consisted of modality application, manual therapy, active therapeutic exercise, and patient education. Physical therapy session duration was investigated for each physical therapy procedure. Data were analyzed in relation to the university hospital, hospital, and clinic. Results: The mean age of subjects was $42.84{\pm}15.46$. There were no significant differences in age among three groups. The number of patients diagnosed with herniated disc were 244(32.15%) and with mechanical low back pain was 187(24.64%). The mean treatment duration per day was 53.22 minutes, and the longest treatment duration was 61.28 minutes at the university hospitals (p<0.001). The mean modality application duration was 42.17 minutes, and the longest application duration was 46.26 minutes at the university hospitals (p<0.001). The mean duration for manual therapy was 5.11 minutes, and the longest treatment duration was 5.97 minutes at clinics. The mean duration for active therapeutic exercise was 4.16 minutes. It was 7.60 minutes at the university hospitals, and 2.48 minutes at clinics. There was a significant difference in active therapeutic exercise duration between university hospitals and clinics(p<0.001). For modalities, hot packs(89.33%) and interferential current therapy(60.87%) were mostly applied. For manual therapy, Soft tissue mobilization(32.93%) and manipulation(14.10%) were mostly applied. In general, treatment application duration was longer at University hospital (p<0.05). For therapeutic exercise, exercise without equipment(18.84%) and muscle strengthening (16.73%) were mostly performed. The longest treatment duration for therapeutic exercise was 7.60 minutes at the university hospital(p<0.05). Conclusion: physical therapy session duration for low back pain was 53.22 minutes. Modality application constitutes 79%, manual therapy 10%, active therapeutic exercise 8% of total treatment duration. It is concluded that patients do not participate actively in treatment procedures.

• Phonetics and Speech Sciences
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• v.4 no.3
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• pp.59-73
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• 2012

This study attempts to investigate the contribution of prosody to the foreign accent in Chinese speakers' English production by examining the synthesized speech of crossing native and non-native talkers' prosody and segments. For the stimuli of the foreign accent ratings, we transplanted gender-matched native speakers' prosody onto non-native talkers' segments and vice versa, utilizing the TD-PSOLA algorithm. Eight English native listeners participated in judging foreign accent and comprehensibility of the transplanted stimuli. Results showed that the synthesized stimuli were perceived as stronger foreign accent regardless of speakers' proficiency when English speakers' prosody was crossed with Chinese speakers' segments. This suggests that segments contribute more than prosody to native listeners' evaluation of foreign accent. When transplanted with English speakers' segments, Chinese speakers' prosody showed a difference in duration rather than pitch between high and low proficiency such that stronger foreign accent was detected when low proficient Chinese speakers' duration was crossed with English speakers' segments. This indicated that prosody, more specifically duration, plays a role though the prosodic role is not overall as significant as segments. According to the post acoustic analysis, the temporal features contributing to making the duration parameter prominent as opposed to pitch were found out to be speaking rate, pause duration and pause frequency. Finally, foreign accent and comprehensibility showed no significant correlation such that native listeners had no difficulty listening to highly foreign accented speech.

• The Korean Journal of Pain
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• v.11 no.2
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• pp.210-213
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• 1998

Background: Epidural steroid therapy has been well-established for the treatment of sciatica and low back pain. Disappointing results following surgical decompression or discectomy have led to wide trials of corticosteroids injected either systemically or into the intraspinally. Although epidural steroid is known to be very effective in the treatment of the patients with low back pain, few data showed the therapeutic duration of epidural steroid. Methods: We studied 120 patients who were treated with epidural steroid for the treatment of low back pain or sciatica or both. We retrospectively analysed the duration of analgesia, number of injections per each session, and complications. Results: The duration of analgesia ranged from 17 days to 300 days, and the mean duration was $73.7{\pm}70.5$ (SD) days. The mean number of injections per each session was $1.8{\pm}1.3$ (range: 1 to 12). There were no significant complications with epidural steroid injections. Conclusions: One to three epidural steroid injections at one week interval leads more than two months of pain relief without significant complications.