• Journal of Aerospace System Engineering
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• v.12 no.2
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• pp.15-22
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• 2018

A compressible multiphase flow was investigated using a DIM consisting of seven equations, including the fifth-order MLP and a modified HLLC Riemann solver to achieve a precise interface structure of liquid and gas. The numerical methods were verified by comparing the flow structures of the high-pressure water and low-pressure air in the shock tube. A 2D air-helium shock-bubble interaction at the incident shock wave condition (Mach number 1.22) was numerically solved and verified using the experimental results.

• Speech Sciences
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• v.1
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• pp.55-81
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• 1997

In the present paper, V-to-V coarticulation in Korean VCV sequences is discussed, focusing on links between consonantal production and degree of V-to-V coarticulation. Temporal and spatial differences between three types of Korean alveolar stops (lax /t/. aspirated /$t^h$/ and thense /t'/) are examined from VCV sequences involving all possible combinations of three Korean unrounded vowels /a, i,/ based on spectrographic and electrographic data(two male speakers and one female speaker and one female speaker respectively). Closure duration and voice onset time (VOT) were measured from acoustic data. 'Total duration', which is defined as the sum of the closure duration and the VOT, was also calculated in order to see the temporal distance between two vowels in a VCV sequence. Differences in lingual-palatal contact pattern at the maximum contact (MC) point between the three types of stop were observed from EPG data. V-to-V coarticulation was investigated by measuring the offset or onset of the second formant (F2) of the target vowels from spectrograms. Two different dimensions of articulation, temporal and spatial, seem to playa role in determining the degree of V-to-V coarticulation. The degree of V-to-V anticipatory coarticulation is influenced by the spatial characteristics of the intervening consonant while the degree of carryover coarticulation is influenced by the temporal characteristics of the consonant.

• Journal of the Korean Ceramic Society
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• v.27 no.5
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• pp.605-612
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• 1990

In Pb1-xLax(Zry, Tiz)1-x/4O3 system, it selects the composition 7/65/35 (x=7, y=65, z=35) that was reported to have eminent Pyroelectric properties, and that is sintered with PbZrO3＋0.3wt.% PbO2 atmosphere powder. From the sintered ceramic and Poly Vinyl Alcohol, the thin wafers are fabricated with 0-3connectivity, and they are researched in Pyroelectric properties and the others according to volume ratio between ceramic and polymer. It was possible to fabricate the film containing ceramic up to 80vol% in PVA polymer. The increment of PLZT ceramic volume fraction improve the pyroelectric coefficient of the composite. On Pyroelectric coefficient and the figure of merit, a little inflection caused by glass point(Tg) of PVA appeared. The degree of inflection is proportioned to the amount of PVA.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.723-728
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• 2008

We performed numerical analysis of base drag phenomenon, when a projectile with backward step flies into atmosphere at supersonic speed. We compared with other researchers. From our previous studies that were 2-dimensional simulation, we found out from sophisticated simulations that need dense mesh points to compare base pressure and velocity profile after from base with experimental data. Therefore, we focus on high order spatial disceretization over 3rd order with TVD such as MUSCL TVD 3rd, 5th, and WENO 5th order, and Limiters such as minmod, Triad. Moreover, we enforce to flux averaging schemes such as Roe, RoeM, HLLE, AUSMDV. In present, one dimensional result of Euler tests, there are Sod, Lax, Shu-Osher and interacting blast wave problems. AUSMDV as a flux averaging scheme with MUSCL TVD 5th order as spatial resolution is good agreement with exact solutions than other combinations. We are carrying out the same approaches into 3-dimensional base flow only candidate flux schemes that are Roe, AUSMDV. Additionally, turbulence models are used in 3-dimensional flow, one is Menter s SST DES model and another is Sparlat-Allmaras DES/DDES model in Navier-Stokes equations.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.30 no.1
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• pp.48-52
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• 2019

Background and Objectives : Functional aphonia is characterized by incomplete closure of the vocal folds. Semi-occluded vocal tract exercise (SOVTE) allows smoothly vocal folds collision without damage to the vocal folds tissues to produce normal vocal intensity. The purpose of this study is to report the effect of SOVTE in patients with functional aphonia. Materials and Method : Seven patients diagnosed with functional aphonia were treated with 1-3 voice therapy sessions using voiced lip-trill, humming, Lax Vox in SOVTE. To assess the effectiveness of semi-occluded vocal tract exercise, cepstral analysis and auditory perceptual assessment were performed before and after voice therapy. Results : F0 (fundamental frequency), CPP (cepstral peak prominence) and L/H ratio (low/high spectral ratio) were significantly increased, while CPP Standard deviation, L/H ratio Standard deviation were decreased. In addition, 'Grade', 'Breathiness' and 'Asthenia' were significantly decreased in the GRBAS scale after SOVTE (p<0.05). Conclusion : In our study, SOVTE seemed to be effective to elicit voice quickly and promote vocal folds vibration without muscular effort in patients with functional aphonia.

• Phonetics and Speech Sciences
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• v.14 no.2
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• pp.11-17
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• 2022

English vowels play an important role in verbal communication. However, Korean students tend to experience difficulty pronouncing a certain set of vowels despite extensive education in English. The aim of this study is to apply speech recognition software to evaluate Korean students' pronunciation of English vowels in minimal pair words and then to examine acoustic characteristics of the pairs in order to check their pronunciation problems. Thirty female Korean college students participated in the recording. Speech recognition rates were obtained to examine which English vowels were correctly pronounced. To compare and verify the recognition results, such acoustic analyses as the first and second formant trajectories and durations were also collected using Praat. The results showed an overall recognition rate of 54.7%. Some students incorrectly switched the tense and lax counterparts and produced the same vowel sounds for qualitatively different English vowels. From the acoustic analyses of the vowel formant trajectories, some of these vowel pairs were almost overlapped or exhibited slight acoustic differences at the majority of the measurement points. On the other hand, statistical analyses on the first formant trajectories of the three vowel pairs revealed significant differences throughout the measurement points, a finding that requires further investigation. Durational comparisons revealed a consistent pattern among the vowel pairs. The author concludes that speech recognition and analysis software can be useful to diagnose pronunciation problems of English-language learners.

• International journal of advanced smart convergence
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• v.12 no.4
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• pp.458-463
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• 2023

This study presents a paper on the implementation of a Raspberry Pi-based educational smart farm system. It confirms that in a real smart farm environment, the control of temperature, humidity, soil moisture, and light intensity can be smoothly managed. It also includes remote monitoring and control of sensor information through a web service. Additionally, information about intruders collected by the Pi camera is transmitted to the administrator. Although the cost of existing smart farms varies depending on the location, material, and type of installation, it costs 400 million won for polytunnel and 1.5 billion won for glass greenhouses when constructing 0.5ha (1,500 pyeong) on average. Nevertheless, among the problems of smart farms, there are lax locks, malfunctions to automation, and errors in smart farm sensors (power problems, etc.). We believe that this study can protect crops at low cost if it is complementarily used to improve the security and reliability of expensive smart farms. The cost of using this study is about 100,000 won, so it can be used inexpensively even when applied to the area. In addition, in the case of plant cultivators, cultivators with remote control functions are sold for more than 1 million won, so they can be used as low-cost plant cultivators.

• Fire Science and Engineering
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• v.27 no.2
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• pp.18-24
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• 2013

Goverment and enterprises have been devoting a lot of dffort in order to prevent the loss of human and property due to a large, diversified fire, explosion, global warming and disasters caused by natural phenomena. But Enterprises came forward and running in the economy priority policy for profit-seeking until now in order to meet the macro purpose of quality improvement of national life and welfare promotion in company with National growth, as a result of lax risk management have had to endure the loss of precious lives and property. According to the '2007 Survey of public safety for the activation of the safety culture' of National Emergency Management Agency [NEMA], a insensitivity of safety in our society was surveyed 'a serious level'. In this study, surveyed need of 'step-by-step fire protection safety management system builds' in order to prevent fire safety accident and improvement of safety awareness level through a systematic management and real condition estimation of not only large business that can control risk management, but also small business that has a big risk to occur accident easily according to small budget and organization.

• 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.

• Archives of Plastic Surgery
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• v.45 no.2
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• pp.135-139
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• 2018

Background Static reconstruction surgery that tightens the tension of the inferior tarsus, thereby raising the lax lower eyelid, is a common treatment for paralytic ectropion of the lower eyelid. We present one such operative procedure, in which an orbicularis oculi muscle flap was used. Methods The surgical technique involves partial resection of the tarsus and the skin, as well as a superior-based orbicularis oculi muscle flap that is sutured to the firm tissue present on the Whitnall tubercle. The muscle flap is approximately 7 mm in width and 15 mm in length, with a superior pedicle that is attached to the tarsus at the medial point of the resected tarsus. The procedure results in contact between the ocular surface and the lower eyelid. Results The procedure was performed in 11 patients with lower eyelid ectropion due to facial paralysis. Ten cases showed a favorable outcome following surgery, with stable results seen over an average follow-up period of 4.5 years. In one case, recurrence of ectropion was observed 2 months after surgery due to an insufficient correction, and the patient required repeat surgery. Conclusions The orbicularis oculi muscle flap was an effective means of suspension and was able to maintain long-term traction tension. This procedure can therefore be considered a favorable treatment option for lower eyelid ectropion due to facial paralysis.