• 말소리와 음성과학
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• 제6권2호
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• pp.107-114
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• 2014

MDVP and Praat are measured by nine variables in common; F0, jitter local, jitter absolute, jitter relative average perturbation, jitter period perturbation quotient, shimmer local, shimmer dB, shimmer amplitude perturbation quotient, and NHR. In the present study, 30 female subjects were divided by their disorders(control group, vocal nodule group), ages(from 18 to 50 years old), gender(women), and severities of voice disorder(GRBAS-G0, G1, G2). Then, the subjects' vowel /a/ was evaluated by MDVP and Praat. First, jitter and shimmer variables of the MDVP were significantly different by severities. Praat showed different jitter, shimmer, and NHR parameters by severities. Second, jitter and NHR levels of MDVP were meaningfully higher than Praat regardless their severities. The result of the research confirms the relationships among GRBAS, MDVP and Praat as well as the differences in acoustic variables between MDVP and Praat.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.522-527
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• 2001

Comprehensive numerical computations are made of side-heated squire cavity which is exposed to zero mean g-jitter. Numerical solutions are acquires to the governing two-dimensional Navier-Stokes equations for a Boussinesq fluid. When the system is exposed to pure sinusoidal g-jitter inclined to the vertical axis, in spite of zero mean gravity there exist non zero net flow fields [8]. The resonance phenomenon are observed in moderate Rayleigh number. And, by comprehensive numerical work, unlike[5], it is found that they are related with the overshoot phenomenon of the sudden gravity up problem.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.48-48
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• 2010

현재 포항가속기연구소의 선형가속기에서 운전되고 있는 모듈레이터는 클라이스트론의 펄스 전원을 공급하는 펄스 전원공급 장치로서 출력은 최대 400 kV, 500 A, $7.5\;{\mu}s$의 펄스를 S band 클라이스트론에 공급한다. 모듈레이터의 고전압펄스 약 40 kV을 스위칭 하기위하여 진공스위치인 싸이라트론 스위치를 사용하고 있다. 모듈레이터 시스템에서 Jitter 발생 요인을 살펴보면, 대부분 싸이라트론 스위치회로에서 발생된다. 싸이라트론이 유발시키는 Jitter는 약 10 ns 이하이므로 매우 적다고 할 수 있다. 스위치의 Jitter가 적음에도 불구하고 모듈레이터 시스템에서 Jitter가 크게 발생한다면, 싸이라트론의 음극(cathode)에서 양극(anode)으로 흐르는 전자빔을 제어하는 Control Grid(G1 & G2)의 pulse 전압의 Jitter가 크기 때문이다. 싸이라트론 Grid 2에 공급되는 pulse 전압의 Jitter를 줄이는 것은 필수적이라 하겠다. 진공스위치인 싸이라트론 Grid에 pulse 전압을 공급하는 싸이라트론 드라이버 시스템의 안정화가 중요하므로 시제품 설계시 안정성을 충분히 고려하였다. 본 발표에서는 시제품으로 제작한 Thyratron Drive System의 기능 및 측정결과에 대해서 기술하고자 한다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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• pp.385-390
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• 2006

This paper examines the sampling and jitter specifications and considerations for Global Navigation Satellite Systems (GNSS) software receivers. Software radio (SWR) technologies are being used in the implementation of communication receivers in general and GNSS receivers in particular. With the advent of new GPS signals, and a range of new Galileo and GLONASS signals soon becoming available, GNSS is an application where SWR and software-defined radio (SDR) are likely to have an impact. The sampling process is critical for SWR receivers, where it occurs as close to the antenna as possible. One way to achieve this is by BandPass Sampling (BPS), which is an undersampling technique that exploits aliasing to perform downconversion. BPS enables removal of the IF stage in the radio receiver. The sampling frequency is a very important factor since it influences both receiver performance and implementation efficiency. However, the design of BPS can result in degradation of Signal-to-Noise Ratio (SNR) due to the out-of-band noise being aliased. Important to the specification of both the ADC and its clocking Phase- Locked Loop (PLL) is jitter. Contributing to the system jitter are the aperture jitter of the sample-and-hold switch at the input of ADC and the sampling-clock jitter. Aperture jitter effects have usually been modeled as additive noise, based on a sinusoidal input signal, and limits the achievable Signal-to-Noise Ratio (SNR). Jitter in the sampled signal has several sources: phase noise in the Voltage-Controlled Oscillator (VCO) within the sampling PLL, jitter introduced by variations in the period of the frequency divider used in the sampling PLL and cross-talk from the lock line running parallel to signal lines. Jitter in the sampling process directly acts to degrade the noise floor and selectivity of receiver. Choosing an appropriate VCO for a SWR system is not as simple as finding one with right oscillator frequency. Similarly, it is important to specify the right jitter performance for the ADC. In this paper, the allowable sampling frequencies are calculated and analyzed for the multiple frequency BPS software radio GNSS receivers. The SNR degradation due to jitter in a BPSK system is calculated and required jitter standard deviation allowable for each GNSS band of interest is evaluated. Furthermore, in this paper we have investigated the sources of jitter and a basic jitter budget is calculated that could assist in the design of multiple frequency SWR GNSS receivers. We examine different ADCs and PLLs available in the market and compare known performance with the calculated budget. The results obtained are therefore directly applicable to SWR GNSS receiver design.

• 대한후두음성언어의학회지
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• 제14권2호
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• pp.104-109
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• 2003

The purpose of this study is to analyze the EGG measures from Lx Speech Studio program (Laryngograph Ltd, UK) in patient with vocal nodule. Thirty female adults (15 patient with vocal nodule, 15 normal speaker) produced sustained vowel and read the passage. They were grouped into three groups based on Grade (GRBAS) : normal-G0, nodule-Gl, nodule-G2. Estimates of Fx (Hz), Qx(%), Jitter, Shimmer, and HNR were made from a 500msec midportion of vowel. In addition, DFx(Hz), DQx(%), CFx(%) and CAx(%) were obtained from reading the passage. These data were compared among groups. The results were as follow Jitter, Shimmer, HNR were significantly higher in nodule-G2 group than in normal-G0 & patient-Gl group. In nodule-G2 group, CFx and CAx from reading passage were significantly higher. For patients with nodule, asymmetry or irregularity were observed in graphs of QxFx ＆ CFx provided by Quantitative Analysis.

• 음성과학
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• 제14권4호
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• pp.213-220
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• 2007

This study investigates the voice quality including F0, jitter, shimmer, and NHR for the children with cochlear implant (CI group) and those with normal hearing (NH group). The CI group was further classified two sub-groups depending upon the time of surgery (i.e. under four years vs. over four years). Three corner vowels (e.g. /a/, /i/, /u/) with extended vocalization were used and analyzed with Multi-Dimensional Voice Program (Kay Elemetrics, Model 4300). The statistics were made in two independent sample t-test with SPSS 11.5. The results can be summarized as follows: (1) The children with cochlear implanted before 4 years of age had very similar data with the NH group except for the vowel /a/. (2) The children with cochlear implanted after 4 years of age, however, indicated significant differences in Fo (/a/, /i/, /u/), Jitter (/e/), shimmer (/a/, /i/, /u/) and NHR(/a/) in all three vowels. It is concluded that the early CI surgery and the early intervention would be very important to maintain better voice quality.

• 대한후두음성언어의학회지
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• 제28권2호
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• pp.84-88
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• 2017

Background and Objectives : The purpose of this study was to compare the usefulness of Cepstral peak prominence (CPP) with parameter of Multiple Dimensional Voice Program (MDVP) in evaluating unilateral vocal fold paraylsis patients with subjective voice impairment. Materials and Methods : From July 2014 to August 2016, 37 patients with unilateral vocal fold paralysis who had been diagnosed with unilateral vocal fold paralysis and had received two or more voice tests before and after the diagnosis were evaluated for maximum phonation time (MPT), MDVP and CPP. Respectively. Voice tests were performed with short vowel /a/ and paragraph reading. Results : The CPP-a (CPP with vowel /a/) and CPP-s (CPP with paragraph reading) of the Cepstrum were statistically negatively correlated with G, R, B, and A before the voice therapy. Jitter, Shimmer, and NHR of MDVP were positively correlated with G, R, B. Jitter, Shimmer, and NHR of the MDVP were significantly correlated with the Cepstrum index. G, B, A and CPP-a and CPP-s showed a statistically significant negative correlation and a somewhat higher correlation coefficient between 0.5 and 0.78. On the other hand, in MDVP index, there was a positive correlation with G and B only with Jitter of 0.4. Conclusion : CPP can be an important evaluation tool in the evaluation of speech in the unilateral vocal cord paralysis when speech energy changes or the cycle is not constant during speech.

• 대한후두음성언어의학회지
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• 제28권2호
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• pp.118-122
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• 2017

Background and Objectives : In unilateral vocal fold paralysis (VFP), medialization thyroplasty (MT), arytenoid adduction (AA) and injection layrngoplasty (IL) are the most common procedures to correct phonatory problems. There is no consensus that which procedure is superior to the other for correcting the glottal insufficiency. The purpose of this study was to compare the phonatory parameters between MT, AA and AA with IL (AA+IL) in patients with unilateral VFP. Materials and Methods : This retrospective study enrolled patients from 2005 to 2016. Total 72 patients (49 male, 23 female, mean age 54.5 years) were classified into three groups ; MT (n=28), AA (n=12), and AA+IL (n=32). GRBAS scales, maximum phonation time (MPT), jitter, shimmer, noise to harmonic ratio (NHR), and voice handicap index (VHI)-10 and VHI-30 were preoperatively and postoperatively collected and compared between the three groups. Results : Age, gender and cause of VFP were not significantly different between the three groups. In MT and AA groups, MPT, VHI, G (overall grade) and B (breathiness) were significantly improved. In AA+IL group, jitter, shimmer, NHR, MPT, VHI, G and B were significantly improved. In analysis of differences (pre-postoperative values), ${\Delta}$ jitter (p<0.001), ${\Delta}$ shimmer (p=0.031), and ${\Delta}$ NHR (p=0.002) were significantly different and AA+IL group showed the greatest improvement. Conclusion : Analysis of voice parameters showed that all the three procedures for patients with unilateral VFP are effective in the improvement of voice ; especially in MPT, VHI-10, G and B scales. Compared to the others, AA+IL provided the better acoustic values including jitter, shimmer and NHR.

• 전자공학회논문지CI
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• 제38권4호
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• pp.33-38
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• 2001

고밀도 기록매체인 DVD RAM 시스템에서 단면 기록밀도 4.7 GB, 15 GB 매체 개발 실현에 가장 큰 걸림돌로 작용하고 있는 crosserase 및 crosstalk 현상이 재생 신호에 미치는 영향을 분석하기 위해 4.7 GB 및 15 GB 규격으로 재생 신호를 시뮬레이션 하였다. 디스크에 조사된 빔의 강도는 Gaussian으로 근사화하고 기록된 마크는 타원형 마크로 가정하였으며, 재생신호는 Gaussian 빔 패턴과 마크 패턴의 이중 적분으로 계산되었다. Crosserase 정도를 변하여 얻어진 재생 신호로부터 주파수 분석을 통하여 3T-11T 마크의 carrier level의 크기를 구하여 비교하였다. 1,000개의 3T-11T 랜덤 마크로 부터 crosserase 및 crosstalk 에 의한 지터를 계산하여 비교한 결과, crosserase에 의한 지터가 crosstalk에 의한 지터 보다 상대적으로 작음을 확인할 수 있었다.

• 대한음성학회:학술대회논문집
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• 대한음성학회 2007년도 한국음성과학회 공동학술대회 발표논문집
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• pp.292-294
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• 2007

This study was designed to compare the translated patient's subjective rating scales for voice evaluation (Voice Handicap Index; VHI, Voice-Related Quality of Life; V-RQOL, Voice Rating Score; VRS) into Korean, taken from 24 professional voice users diagnosed with organic voice disorders. First, the correlation amongh those scales were observed. Second, the correlation between the patient's subjective rating scales and acoustic measures (Jitter%, Shimmer%, NHR) were examined. Third, those scales were compared by clinician's objective scale (G in GRBAS scale). Results indicated that significant correlations among the patients' subjective rating scales and significant correlations of clinician's rating scale with jitter% and Shimmer%, but not with NHR were observed. In addition, there were significant correlations of G with VHI and VHI-P (one of subscale of VHI). However, none of acoustic measures were correlated with the patient's subjective rating scales.