• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05b
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• pp.10-14
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• 2005

Zinc Oxide(ZnO) thin films on Si (100) substrates were deposited by RF magnetron reactive sputtering. The characteristics of zinc oxide thin films with changing sputtering conditions such as argon/oxygen gas ratios, RF power, and substrate temperature, chamber pressure and target-substrate distance were investigated. To analyze a crystallographic properties of the films, $\theta/2{\theta}$ mode X -ray diffraction, SEM, and AFM analyses. C-axis preferred orientation, resistivity, and surface roughness highly depended on Ar/$O_2$ gas ratios. The resistivity of ZnO thin films rapidly increased with increasing oxygen ratio and the resistivity value of $9{\times}10^7\;{\Omega}cm$ was obtained at a working pressure of 10 mTorr with Ar/$O_2$=50/50. The surface roughness was also improved with increasing oxygen ratio and the ZnO films deposited with Ar/$O_2$=50/50 showed the excellent roughness value of $28.7{\AA}$.

• Phonetics and Speech Sciences
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• v.10 no.4
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• pp.163-171
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• 2018

A mixed dysarthria with combinations of hypokinetic, ataxic, and spastic components is a common clinical feature of multiple system atrophy (MSA). Due to the rapid progress of dysarthria after diagnosis, people with MSA experience difficulty with verbal communication, which eventually affects their quality of life negatively. In this study, SPEAK $OUT!^{(R)}$, an intensive 1:1 treatment of dysarthria for improving functional communicative ability, was provided to twelve people with MSA. To evaluate the efficacy of SPEAK $OUT!^{(R)}$ in people with MSA, aerodynamic, acoustic, and perceptual analyses were conducted. Pre-and post-therapy data included maximum phonation time, vocal intensity, and fundamental frequency during /a/ sustained phonation and passage reading; frequency range between high /a/ and low /a/ phonation; jitter, shimmer, and HNR for vocal quality; speech rate during passage reading; and perceptual evaluation scores for articulation precision and intonation. The participants achieved statistically significant improvement in vocal intensity, pitch range, vocal quality, speech rate, and speech intelligibility. In conclusion, SPEAK $OUT!^{(R)}$ is a feasible treatment for people with MSA to efficaciously improve their speech ability.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.68.3-69
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• 2020

We develop a series of N-body data challenges, functional to the final analysis of the extended Baryon Oscillation Spectroscopic Survey (eBOSS) Data Release 16 (DR16) galaxy sample, primarily based on high-fidelity catalogs constructed from the Outer Rim simulation. We generate synthetic galaxy mocks by populating Outer Rim halos with a variety of halo occupation distribution (HOD) schemes of increasing complexity, spanning different redshift intervals. We then assess the performance of three complementary redshift space distortion (RSD) models in configuration and Fourier space, adopted for the analysis of the complete DR16 eBOSS sample of Luminous Red Galaxies (LRGs). We find that all the methods are mutually consistent, with comparable systematic errors on the Alcock-Paczynski parameters and the growth of structure, and robust to different HOD prescriptions - thus validating the robustness of the models and the pipelines used for the baryon acoustic oscillation (BAO) and full shape clustering analysis. Our study is relevant for the final eBOSS DR16 'consensus cosmology', as the systematic error budget is informed by testing the results of analyses against these high-resolution mocks. In addition, it is also useful for future large-volume surveys, since similar mock-making techniques and systematic corrections can be readily extended to model for instance the DESI galaxy sample.

• The Journal of the Acoustical Society of Korea
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• v.28 no.8
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• pp.822-831
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• 2009

The porcelain insulators are important devices, that are used to isolate electrically and hold mechanically in the high-voltage power transmission systems. The faults of the insulators induce very serious problems to the power transmission line. In this paper, we introduce techniques for fault detections of insulators by acoustic radiation noises from them. We measured radiation noises from normal state insulators and fault state insulators. The used insulators were two different type porcelain insulators, a cut out switch, two different type line posters, and a lightning arrester. Each results was compared each other in time domain, frequency domain and filter banks' outputs. We found the possibility of detection of insulators' faults and also suggested techniques for fault detections.

• Phonetics and Speech Sciences
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• v.16 no.1
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• pp.11-16
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• 2024

The fundamental frequency (f0), representing an acoustic measure of vocal fold vibration, serves as an indicator of the speaker's emotional state and language-specific pattern in daily conversations. This study aimed to examine the f0 distribution in an English corpus of spontaneous speech, establishing normative data for American speakers. The corpus involved 40 participants engaging in free discussions on daily activities and personal viewpoints. Using Praat, f0 values were collected filtering outliers after removing nonspeech sounds and interviewer voices. Statistical analyses were performed with R. Results indicated a median f0 value of 145 Hz for all the speakers. The f0 values for all speakers exhibited a right-skewed, pointy distribution within a frequency range of 216 Hz from 75 Hz to 339 Hz. The female f0 range was wider than that of males, with a median of 113 Hz for males and 181 Hz for females. This spontaneous speech corpus provides valuable insights for linguists into f0 variation among individuals or groups in a language. Further research is encouraged to develop analytical and statistical measures for establishing reliable f0 standards for the general population.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.9
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• pp.599-605
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• 2015

The revised U.S. Nuclear Regulatory Commission(NRC), Regulatory Guide(RG) 1.20, rev.3 requires the evaluation of the potential adverse effects from pressure fluctuations and vibrations on piping and components for the reactor coolant, steam, feedwater, and condensate systems. Detailed vibration analyses for the systems attached to the steam generator are very difficult, because these piping systems are very complicated. This paper suggests a screening method for the flow-induced vibration of acoustic resonances and pump-induced vibration of the piping systems attached to the steam generator in order to conduct the APR1400 comprehensive vibration assessment program. This paper seeks to address the areas such as potential vibration sources, and methods to prevent the occurrence of acoustic resonances and pump-induced vibration of piping systems attached to the steam generator, for conducting the APR1400 comprehensive vibration assessment program. The screening method in this paper will be used to estimate the flow-induced vibration of the piping systems attached to the steam generator for the APR1400.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.21 no.1
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• pp.37-41
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• 2010

Background and Objectives : Transient minor voice changes after thyroidectomy are not infrequent complaints even in cases without any evidence of recurrent laryngeal nerve damage. However, clinical course, diagnosis and management of such voice changes are not fully understood. This study aimed to evaluate the clinical characteristics of minor voice changes after thyroidectomy. We also tried to assess the significance and feasibility of superior laryngeal nerve monitoring and to find out the optimal evaluation tools for such voice changes after thyroidectomy. Materials and Method : Nine adult patients who received total thyroidectomy without evidence of recurrent laryngeal nerve injury were enrolled for this prospective study. Voice evaluations were performed preoperatively and 3 months postoperatively ; acoustic analyses including voice range profile, aerodynamic study, stroboscopic evaluation and subjective voice assessment with questionnaires. The external branch of superior laryngeal nerve was monitored by nerve stimulator after ligation of superior thyroidal vessels. Results: Four of nine patients complained their voice change at 3 months after the surgery. Three of them reported complete recovery of their voice at 6 months after the surgery. Acoustic analysis revealed significant decrease in their phonatory range especially with high tone loss. Questionnaires related to singing was more sensitive than previously well-known "voice handicap index". Stimulation of the superior laryngeal nerve was feasible in most of the cases (94.4%), but it failed to show any correlation with minor voice changes after thyroidectomy. Conclusion : Minor voice changes were not rare events during the first 6 month after thyroidectomy. Decrease in phonatory range with high tone loss and therefore, discomfort in singing was the most common finding. Superior laryngeal monitoring was feasible but it was not a sensitive tool for the prediction of minor voice change after thyroidectomy.

• 재활복지
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• v.18 no.4
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• pp.237-255
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• 2014

Idiopathic Parkinson disease(IPD) is an neurodegenerative disease caused by the loss of dopamine cells in the substantia nigra, a region of midbrain. Its major symptoms are muscular rigidity, bradykinesia, resting tremor, and postural instability. An estimated 70~90% of patients with IPD also have hypokinetic dysarthria. Subthalamic nucleus deep brain stimulation (STN-DBS) has been reported to be successful in relieving the core motor symptoms of IPD in the advanced stages of the disease. However, data on the effects of STN-DBS on speech performance are inconsistent. A medline literature search was done to retrieve articles published from 1987 to 2012. The results were narrowed down to focus on speech performance under STN-DBS based perceptual, acoustic, and/or aerodynamic analyses. Among the 32 publications which dealt with speech performance after STN-DBS indicated improvement(42%), deterioration(29%), mixed results(26%), or no change(3%). The most favorite method was found to be based upon acoustic analysis by using a vowel prolongation and Unified Parkinson's Disease Rating Scale(UPDRS). For the purpose of verifying the effect of the STN-DBS, speech evaluation should be undertaken on all speech components such as articulation, resonance, phonation, respiration, and prosody by using a contextual speech task.

• Geophysics and Geophysical Exploration
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• v.2 no.1
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• pp.33-42
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• 1999

AVO and complex trace analyses mainly used to characterize natural gas reservoir were tested in this paper for a possible application to detection of major geological discontinuities such as fracture zones. The test data used in this study were calculated by utilizing a viscoelastic numerical program which was based on the generalized Maxwell body for a horizontal fracture model. In AVO analysis of a horizontal fracture zone, p-wave reflection appears to be variant depending upon the acoustic-impedence contrast and the offset distance. The fracture zone is also effectively clarified both in gradient stack and range-limited stack in which fracture zone reflection is attenuated with the increasing offset distance. In complex attribute plots (instantaneous amplitude, frequency, and phase), the top and bottom of the fracture Tone are characterized by a zone of strong amplitudes and an event of the same phase. Low frequency characteristics appear at the fracture zone and the underneath. Amplitude attenuation and waveform dispersion are dependent on Q-contrast between the fracture zone and the surrounding media. They were properly compensated by optimum inverse Q-filtering.

• Journal of Korean Academy of Nursing
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• v.46 no.4
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• pp.475-489
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• 2016

Purpose: This study was a systematic review and meta-analysis designed to investigate the effects of stimulation-oriented interventions for behavioral problems among people with dementia. Methods: Based on the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA), a literature search was conducted using seven electronic databases, gray literature, and other sources. Methodological quality was assessed using the Scottish Intercollegiate Guidelines Network (SIGN) for randomized controlled trials (RCTs). Data were analyzed using R with the 'meta' package and the Comprehensive Meta-Analysis (CMA 2.0) program. Results: Sixteen studies were included for meta-analysis to investigate the effect of stimulation-oriented interventions. The quality of individual studies was rated as '++' for eight studies and '+' for the rest. The effect sizes were analyzed according to three subgroups of interventions (light, music, and others); Hedges' g=0.04 (95% CI: -0.38~0.46), -0.23 (95% CI: -0.56~0.10), -0.34 (95% CI: -0.34~0.00), respectively. To explore the possible causes of heterogeneity ($I^2=62.8%$), meta-regression was conducted with covariates of sample size, number of sessions, and length of session (time). No moderating effects were found for sample size or number of sessions, but session time showed a significant effect (Z=1.96, 95% CI: 0.00~0.01). Finally, a funnel plot along with Egger's regression test was performed to check for publication bias, but no significant bias was detected. Conclusion: Based on these findings, stimulation-oriented interventions seem to have a small effect for behavioral problems among people with dementia. Further research is needed to identify optimum time of the interventions for behavioral problems among dementia pateints.