• Phonetics and Speech Sciences
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• v.1 no.4
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• pp.47-59
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• 2009

The purpose of this paper is to propose an automatic evaluation technique for the prosodic aspect of an English sentence uttered by Korean speakers learning English. The underlying hypothesis is that the consistency of the manual prosody scoring is reflected in an imaginary space of prosody evaluation model constructed out of the three physical properties of the prosody considered in this paper, namely: the fundamental frequency (F0) contour, the intensity contour, and the segmental durations. The evaluation proceeds first by building a prosody evaluation model for the sentence. For the creation of the model, utterances from native speakers of English and Korean learners for the target sentence are manually scored by either native teachers of English or Korean phoneticians in terms of their prosody. Multiple native utterances from the manual scoring are selected as the "model" native utterances against which all the other Korean learners' utterances as well as the model utterances themselves can be semi-automatically evaluated by comparison in terms of the three prosodic aspects [7]. Each learner utterance, when compared to the multiple model native utterances, produces multiple coordinates in a three-dimensional space of prosody evaluation, each axis of which corresponds to the three prosodic aspects. The 3D coordinates from all the comparisons form a prosody evaluation model for the particular sentence and the associated manual scores can display regions of particular scores. The model can then be used as a predictive model against which other Korean utterances of the target sentence can be evaluated. The model from a Korean phonetician appears to support the hypothesis.

• Journal of the Korean Society of Safety
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• v.22 no.5
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• pp.27-32
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• 2007

We investigated the damage of the TTL ICs which manufactured five different technologies by artificial microwave. The artificial microwave was rated at a microwave output from 0 to 1000W, at a frequency of 2.45GHz. The microwave power was extracted into a standard rectangular waveguide(WR-340) and TTL ICs were located into the waveguide. TTL ICs were damaged two types. One is breakdown which means no physical damage is done to the system and after a reset the system is going back into function. The other is destruction which means a physical damage of the system so that the system will not recover without a hardware repair. TTL SN74S08N and SN74ALS08N devices get a breakdown and destruction occurred but TTL SN74LS08N, SN74AS08N and 74F08N devices get a destruction occurred. Also destructed TTL ICs were removed their surface and a chip conditions were analyzed by SEM. The SEM analysis of the damaged devices showed onchipwire and bondwire destruction like melting due to thermal effect. The tested results expect to be applied to the fundamental data which interprets the combination mechanism of the semiconductors from artificial microwave environment.

• Phonetics and Speech Sciences
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• v.5 no.4
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• pp.25-32
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• 2013

This research is aimed at finding the acoustic characteristics of different voice rehabilitation techniques, the electrolaryx (EL), standard esophageal (SE), and tracheoesophageal (TE), used on 17 patients with laryngectomees. The analysis of the voice qualities was achieved using MDVP. In order to compare the acoustic characteristics, patients were asked to produce the vowel /a/ sound. The acoustic analysis included fundamental frequency (f0), jitter, shimmer, and noise-to-harmonic ratio (NHR). The main acoustic results showed no significant statistical differences between the average measurements of SE and TE speakers. It was found that the current study showed the same tendency found in previous studies. There was also a significant difference between SE and EL speakers. On the other hand, there were no significant statistical differences between the average measurements of TE and EL speakers on all acoustic measurements. This research will contribute to establishing a baseline related to speech characteristics in voice rehabilitation for patients with laryngectomees. In future, the present findings and issues should be considered in the context of gender. Specifically, the number of women who are diagnosed with laryngeal cancer continues to rise and their acoustic characteristics may indeed differ from those of men.

• The Journal of Korean Society for School & Community Health Education
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• v.13 no.2
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• pp.93-105
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• 2012

This study aimed to provide the fundamental resources for developing an effective safety education program. We analyzed the condition of school accidents and safety awareness, and the condition of school safety education and the factors related to safety education. Ultimately, this study can lead the following studies to develop the safety education program realistically, which can effectively change the safety behaviors of Korean students. Methods: We carried out a questionnaire survey that was targeted at the schools - three elementary, three middle, and three high schools - located in Chung-nam, from April 1, 2012 to May 2, 2012. Totally, the questionnaires of 578 students were fully filled out. The design of this study is a descriptive research. Results: 1. 64.5% of elementary school students, 33% of middle school students and 32% of high school students had experienced more than one safety accident. The frequency of occurrence was the highest in playgrounds for elementary and middle school students, and in stairs for high school students. The most safety accidents occurred during lunch time and at recess in elementary and middle school, and at recess in high school. Further, most of the students who had experienced the safety accidents had been treated in infirmary (school nurse's office) for elementary school students, and in a hospital for middle and high school students. 2. There was statistical significance in the safety consciousness for students in elementary school (18.09 points), middle school (17.68 points), and high school (17.26 points), on a twenty-point scale. (F=3.754, p=0.024). 3. Comparing the factors related to school safety education with safety consciousness, students in elementary school that gave an answer of the usefulness of safety education showed a high standard in the safety consciousness level. (F=12.347, p=0.002) For the need of safety education, the students in the elementary school and high school that expressed the necessity of safety education showed a high standard in the safety consciousness level. Conclusions: Accordingly, it is true that there are the differences at safety awareness among elementary middle high school students. This study is meaningful enough in that it provides the fundamental resources for developing the effective safety education methods for the subjects.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.27 no.2
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• pp.108-113
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• 2016

Background and Objectives : After thyroidectomy, many patients experience problems report such things as reduced voice range and vocal fatigue, swallowing problems without superior and recurrent laryngeal nerve injury. The purpose of this study was to evaluate voice and swallowing problems before and after thyroid surgery without laryngeal nerve injury. Materials and Methods : Ninety-three patients who underwent thyroidectomy without laryngeal nerve injury and completed the follow-up evaluations were studied between June 2013 and December 2015. Each evaluation was performed preoperatively, as well as 1 week, 1 month postoperatively. Analysis was performed including voice handicap index (VHI), dysphagia handicap index (DHI), and acoustic voice analysis. Results : Patients show significant variation of parameters in the fundamental frequency (F), maximal phonation time (MPT), shimmer, jitter and soft phonation index (SPI) early after operation, and most of them showed recovery of parameters after 1month of operation. Perceptive complaint of voice and swallowing also showed significant decreased after operation (p<0.005). After 1month of operation, MPT, highest frequency and frequency ranges still showed significant decreased parameters. Comparing acoustic and perceptive parameters of total thyroidectomy and lobectomy, there was no significant changes between them except highest frequency (p=0.042). Conclusion : The results from both subjective and objective evaluations show voice and swallowing disturbance after thyroidectomy even in the absence of laryngeal nerve and provide patients information about the recovery process after surgery. Highest frequency parameter showed most significant changes after operation.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.13 no.2
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• pp.139-144
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• 2002

Background and objectives : The various voice-conserving treatments are used for Tla staged glottic cancer. Especially, Tla staged glottic cancer has been shown excellent treatment result after laser cordectomy or radiotherapy. To evaluate which treatment results better voice after treatment made it valuable to define the exact indication and recommending treatment modality on the Tla staged glottic cancer patients. Method : The medical records of 75 patients with glottic TlaN0 cancer diagnosed at Asan medical center, University of Ulsan college of medicine form May, 1989 to July,2001 were retrospectively reviewed on the point of voice quality and oncology including 5-year survival rate and local control rate. Results : Laser cordectomy and radiotherapy showed 100% and 94.0% 5-year survival rate, respectively. And laser cordectomy had 94.3% local control rate while radiotherapy got 87.6% local control rate. Voice analysis of pretreatment and posttreatment were used to compare each result. Fundamental frequency(F0), shimmer, jitter, noise to harmony ratio(NHR), maximum confortable phonation time(MPT) and vocal efficiency(VE) were used for parameters for voice analysis. Only in shimmer and MPT, we could find significant posttreatment difference between two therapies. In addition, we reviewed the total expenses for each therapy. Conclusion : On the basis of the oncologic result, both the laser cordectomy and radiotherapy had the similar results. Laser cordectomy showed the relatively acceptable voice as radiotherapy did. Laser cordectomy cost less than radiotherapy did. Laser cordectomy can be used for treatment about Tla staged glottic cancer.

• Advances in Energy Research
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• v.5 no.3
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• pp.219-226
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• 2017

Electrochemical double layer capacitors (EDLCs) have received a tremendous interest due to their suitability for diverse applications. They have been fabricated using different carbon based electrodes including activated carbons, single walled/multi walled carbon nano tubes. But, graphite which is one of the natural resources in Sri Lanka has not been given a considerable attention towards using for EDLCs though it is a famous carbon material. On the other hand, EDLCs are well reported with various liquid electrolytes which are associated with numerous drawbacks. Gel polymer electrolytes (GPE) are well known alternative for liquid electrolytes. In this paper, it is reported about an EDLC fabricated with a nano composite polyethylene oxide based GPE and two Sri Lankan graphite based electrodes. The composition of the GPE was [{(10PEO: $NaClO_4$) molar ratio}: 75wt.% PC] : 5 wt.% $TiO_2$. GPE was prepared using the solvent casting method. Two graphite electrodes were prepared by mixing 85% graphite and 15% polyvinylidenefluoride (PVdF) in acetone and casting n fluorine doped tin oxide glass plates. GPE film was sandwiched in between the two graphite electrodes. A non faradaic charge discharge mechanism was observed from the Cyclic Voltammetry study. GPE was stable in the potential windows from (-0.8 V-0.8 V) to (-1.5 V-1.5 V). By increasing the width of the potential window, single electrode specific capacity increased. Impedance plots confirmed the capacitive behavior at low frequency region. Galvanostatic charge discharge test yielded an average discharge capacity of $0.60Fg^{-1}$.

• Phonetics and Speech Sciences
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• v.16 no.2
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• pp.49-58
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• 2024

This study aimed to compare the acoustic measurements of speech samples recorded from individuals with normal voices using various devices: the Computerized Speech Lab (CSL), a unidirectional wired pin-microphone (WIRED) suitable for smartphones, the built-in omnidirectional microphone (SMART) of smartphones, and Bluetooth-connected wireless earphones, specifically the Galaxy Buds2 Pro (WIRELESS). This study included 40 normal adults (12 males and 28 females) who had not visited an otolaryngologist for respiratory diseases within the past three months. Participants performed sustained vowel /a/ phonation for four seconds and reading tasks with sentences ("Walk") and paragraphs ("Autumn") in a sound-treated booth. Recordings were simultaneously conducted using the four different devices and synchronized based on the CSL-recorded samples for analysis using the MDVP, ADSV, and VOXplot programs. Compared with CSL, the Cepstral Spectral Index of Dysphonia (CSID_V, CSID_S) and Acoustic Voice Quality Index (AVQI) values were lower in the WIRED and higher in the SMART. The opposite trend was observed for the L/H spectral ratios (SR_V and SR_S), and the WIRELESS demonstrated task-specific discrepancies. Furthermore, both the fundamental frequency (F0) and the cepstral peak prominence of the vowel samples (CPP_V) had intraclass correlation coefficient (ICC) values above 0.9, indicating high reliability. These variables, F0 and CPP_V were considered highly reliable for voice recordings across different microphone types. However, caution should be exercised when analyzing and interpreting variables such as the SR, CSID, and AVQI, which may be influenced by the type of microphone used.

• The Journal of the Acoustical Society of Korea
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• v.26 no.6
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• pp.250-258
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• 2007

Current speech recognition technology s achieved high performance with the development of hardware devices, however it is insufficient for some applications where high reliability is required, such as voice control of powered wheelchairs for disabled persons. For the system which aims to operate powered wheelchairs safely by voice in real environment, we need to consider that non-voice commands such as user s coughing, breathing, and spark-like mechanical noise should be rejected and the wheelchair system need to recognize the speech commands affected by disability, which contains specific pronunciation speed and frequency. In this paper, we propose non-voice rejection method to perform voice/non-voice classification using both YIN based fundamental frequency(F0) extraction and reliability in preprocessing. We adopted a multi-template dictionary and acoustic modeling based speaker adaptation to cope with the pronunciation variation of inarticulately uttered speech. From the recognition tests conducted with the data collected in real environment, proposed YIN based fundamental extraction showed recall-precision rate of 95.1% better than that of 62% by cepstrum based method. Recognition test by a new system applied with multi-template dictionary and MAP adaptation also showed much higher accuracy of 99.5% than that of 78.6% by baseline system.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.14 no.1
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• pp.15-35
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• 2010

Objectives : The purpose of this study is to find out the correlation between the Vocal indicators and the 'Buzhongyiqi-Tang questionnaire' and the 'Chalder fatigue scale.' Methods : This study examined the mean value of each factor in the 'Buzhongyiqi-Tang Questionnaire,' 'Chalder fatigue scale' and the different voice indicators conducted on 81 healthy adult participants in relation to the results of the /a/ /e/ /i/ /o/ /u/ pronunciation test. Results : There was significant correlation between the pronunciation of /a/ /e/ /i/ /o/ /u/ vowels' F0 indexes and 'the Deficiency symptoms of Buzhongyiqi-Tang'. The results of the regression analysis showed the following significant findings for each pronouncing vowels: /i/ as a factor for 'the Deficiency symptoms of Buzhongyiqi-Tang'.; /a/ for 'the Consumptive fever of Buzhongyiqi-Tang'.; /i/ for 'the Vocal inflammation of Buzhongyiqi-Tang.; and /e/ as a factor of 'the Chadler physical fatigue'. Conclusions : The study showed a negative correlation between the Fundamental Frequency and the mean value of the questionnaire, which could be understood as higher the fatigue level, increased level of vocal vibration and higher pitch tone compared to the less fatigued group. We expect future studies to conduct research on methods to diagnose other illnesses using the vocal indicators based on the correlation between the vocal index and illnesses prescribed under traditional oriental medicine.