• Journal of Veterinary Clinics
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• v.34 no.5
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• pp.330-334
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• 2017

The aim of this study was to establish an injection protocol of a test bolus and a main bolus of contrast material for computed tomographic pulmonary angiography (CTPA) for visualizing optimal pulmonary arteries in normal beagle dogs. CTPA using a test bolus method from either protocol A or B were performed in each of four normal beagle dogs. In protocol A, CTPA was conducted with a scan duration for around 8 s, setting the contrast enhancement peak of the pulmonary trunk in the middle of the scan duration. The arrival time to the contrast enhancement peak was predicted from a previous dynamic scan using a test bolus (150 mg iodine/kg) injected with the same injection duration using for a main bolus (450 mg iodine/kg). In protocol B, CTPA was started at the predicted appearance time of contrast material in the pulmonary trunk based on a previous dynamic scan using a test bolus injected with the same injection rate as a main bolus. CTPA using protocol A showed the optimal opacification of the pulmonary artery with pulmonary venous contamination. Proper CTPA images in the absence of venous contamination were obtained in protocol B. CTPA with a scan duration for 8 s should be started at the appearance time of contrast enhancement in the pulmonary trunk, which can be identified exactly when a test bolus is injected at the same injection rate used for the main bolus.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.1
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• pp.89-97
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• 2018

The test results of a 7-tonf-class engine for the third-stage engine of KSLV-II are presented. Hot-firing tests performed with two engineering model engines are classified into ground tests and high-altitude tests according to the test conditions. The operability verification of the engines were carried out through short and long duration tests. The full duration test performed for the durability verification of the engines revealed a few of items to be improved. Synthetically, encouraging data of adding power to engine development were obtained from the test results. New engines based on these results will be manufactured and consistently verified through hot-firing tests.

• Journal of Applied Reliability
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• v.12 no.3
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• pp.139-152
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• 2012

Successive and simultaneous sudden death tests are compared with the complete and Type II censored samples in terms of expected test duration and Total Time on Test(TTT) subject to the same number of failures in order to maintain the equal statistical precision under Weibull lifetime distribution with known shape parameter. Also, two sudden death tests under a proposed cost model are discussed and a numerical example is provided to illustrate the use of the proposed cost model.

• English Language & Literature Teaching
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• v.15 no.2
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• pp.261-280
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• 2009

This study focuses on providing the pedagogical implications of stress in English pronunciation teaching since stress is one the most important characteristic factors in English pronunciation (Bolinger, 1976; Brown, 1994; Celce-Murcia, Brinton & Goodwin, 1996; Kreidler, 1989). The author investigated stress production regarding in terms of duration, pitch, and intensity by a group of native speakers of English and a group of low-proficiency South Kyungsang Korean college students for their pre-test. For both of the pre- and post-test, the same stimuli, which consisted of a one-syllable word, two two-syllable words, three three-syllable words, and three four-syllable words, were used along with the various sentence positions: isolation, initial, medial, and final. Soft ware programs, ALVIN and Praat, were used to record and analyze the data. Since Celce-Murcia et al. (1996), Klatt (1975), and Ladefoged (2001) treat duration of the stressed syllable more significantly than other factors, pitch and intensity, with respect to the listener's point of view, the author developed a special method of teaching English stress using a traditional Korean drum to emphasize duration. In addition, the results from the native speakers' production showed that their main strategy to realize stress was through lengthening stressed syllables. After six weeks of stress instruction using the drum, the production of the native speakers and the SK Korean participants from the pre- and post-test were compared. The results from the post-test indicated that the participants showed great improvement not only in duration but also in pitch after the stress instruction. Pitch improvement was unexpected but well-explained by the statement that long vowels receive accent in loan word adaptation in North Kyungsang Korean. The results also showed that the Korean participants' pitch values became more even in their duration values for each syllable as the structure of the word or the sentence became more complex, due to their dependency upon their L1.

• 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.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.29 no.1
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• pp.93-102
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• 2016

Objective : This study performed to evaluate that duration of acne scars effects on Qualitative Global Acne Scarring Grading System(QGASC) grade changing and treatment duration. Also this study performed to evaluate the relationship between dysmenorrhea and acne scars, and the effects of each treatment on treatment duration and Korean Acne Grading System(KAGS) and QGASC grade.Methods : 95 patients with acne scars were understood by medical records and case photos, and we evaluated pre and post acne scar grade based on KAGS and QGASC. We analyzed data by SPSS 22 for windows program, and figured out the relation between duration of acne and QGASC grade and treatment duration by Spearman correlation analysis, and performed Mann-Whitney U-test to figure out the relation between dysmenorrhea and QGASC grade. We performed Wilcoxon test to evaluate that treatment of acne scars effects on KAGS grade and QGASC grade, and performed Kruskal-Wallis test to figure out the difference of each treatment which effects on KAGS grade and QGASC grade, and performed Post-hoc analysis to figure out the group comparison.Results & Conclusions : QGASC grade depending on duration of acne was statistically significance. Subcision and Microneedle Therapy System(MTS) and pharmacopuncture were significantly improved acne scars. Other treatments were significantly more effective than subcision and pharmacopuncture combined treatment. Treatment duration of Subcision and MTS combined treatment was significantly most shortest than other treatment.

• Journal of Pharmaceutical Investigation
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• v.20 no.3
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• pp.115-119
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• 1990

The reaction rates, duration times and neutralizing capacities of the antacids which are frequently used in Korean market and three different commercial combination products were evaluated in vitro by Fuchs method and Johnson-duncan method, respectively. In vivo tests of combination products were determined in the fasted state of rat by Aspiration method. Comparing the result of in vitro test with that of in vivo test, the maximal pH was lowered by 2-3 value and the durational time increased by two folds in vivo test. Each antacid composition and combination products from three phamaceutical companies (A, B, and C) were studied, respectively. The duration times measured by Fuchs method were double compared to those by Johnson-Duncan method. A and C preparation maintained the pH range from 3 to 7 for 60 min by Fuchs method. In vovo test, maximum pH of A, B and C preparation was 6.50, 3.65, 2.65 and duration time of those was 200, 500, 0 min, respectively.

• Journal of Korean Society for Quality Management
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• v.34 no.1
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• pp.20-26
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• 2006

In the fields of mechanical reliability application, "zero" or "zero or one" failure tests are most commonly used for demonstrating reliability of a product since they reduce test duration and/or sample size compared to other test methods that guarantees the same reliability of a product with a given confidence level or consumer's risk. The test duration of the "zero or one" failure test is longer than that of "zero" failure test but it has advantage of smaller producer's risk. In this paper a two-stage test is developed that compromises the "zero" and "zero or one" failure tests. The properties of the proposed two-stage test are investigated and the three test methods are compared using a numerical example.

• 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.

• Speech Sciences
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• v.15 no.4
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• pp.97-105
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• 2008

Nowadays an HMM-based text-to-speech system (HTS) has been very widely studied because it needs less memory and low computation complexity and is suitable for embedded systems in comparison with a corpus-based unit concatenation text-to-speech one. It also has the advantage that voice characteristics and the speaking rate of the synthetic speech can be converted easily by modifying HMM parameters appropriately. We implemented an HMM-based Korean text-to-speech system using a small size Korean speech DB and proposes a method to increase the naturalness of the synthetic speech by controlling duration model parameters in the HMM-based Korean text-to speech system. We performed a paired comparison test to verify that theses techniques are effective. The test result with the preference scores of 73.8% has shown the improvement of the naturalness of the synthetic speech through controlling the duration model parameters.