• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.10
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• pp.1197-1205
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• 2014

Recently signal transmission of ultra high-definition(4K-UHD) video system is transferred as uncompressed high speed data. However, this has a limit to compose the system because EMI between separate cables of high speed interface section and skew bring distortion of the video signal and jitter. In this paper we applied V-by-One HS interface technique to transfer uncompressed high speed data. We analyzed HSD(High Speed Differential) transmission line signal integrity. Also we applied RF transmission technique instead of UHD video pattern control interface PCB design. When we measured V-by-One HS video signal of designed 4K-UHD class signal generator, We found that the transmission performance has been signal standard.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.5
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• pp.472-482
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• 2008

A modulation transfer function(MTF) tree is established to estimate the overall MTF of an observation satellite and to analyze the image performance. Basic MTF models relevant to each MTF tree component are represented as mathematical relationship between optics-structural dynamics, thermal deformation, attitude and dynamic characteristics of a satellite and the effects due to the space environment. The Basic MTF models consist of diffraction limited MTF with central obscuration, aberration, defocus, line-of-sight(LOS) jitter, linear motion, detector integration, and so forth. Performance estimation is demonstrated for a virtual earth-observation satellite in order to validate the constructed modeling method. The proposed models enable the system engineers to calculate the overall system MTF and to determine the crucial design parameters that affect the image performance in the conceptual design phase of an observation satellite.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.9-14
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• 2020

In this paper, Qualification Model of frequency synthesizer is designed for X-band SAR system and performed electrical and environment test. Designed frequency synthesizer generate 13.65 GHz with very low phase noise performance. The integrated phase noise from 10Hz to 1MHz is -37.91 dBc. IRF performances are analyzed according to phase noise and jitter. Also, thermal and structure analysis are achieved for stable operation in space environment. Designed frequency synthesizer is consist of 2 modules of 6U size and generate L-band, C-band, Ku-band. The result of this study would enhance the design ability of RF module and help the frequency synthesizer design for SAR payload system.

• The Journal of the Korea Contents Association
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• v.8 no.4
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• pp.63-70
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• 2008

This paper presents a method of PRI do-interleaving for LASER pulse signals. When the PRI of LASER pulse is periodically changed, the first deviation and the second deviation of TOA is used to calculate the PRI pattern of input LASER signals of receiver. If the standard deviation of the first difference of TOA is less than 5% of the average of the first difference of TOA, the PRI pattern of LASER signal is fixed or jittered type. If the standard deviation is larger than 5% of the average, those are triangular PRI patterns or sawtooth PRI patterns.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.11 no.1
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• pp.46-50
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• 2000

Background and Objectives : Hormonal treatments which have an androgenic effect have the potential to cause vocal changes. The changes in vocal fold structure and voice quality are considered to be irreversible. To date, studies have documeted subjective vocal changes or documented single cases without detailed, baseline voice assessments. Materials and Methods : We have performed objective voice analyses of 20 women who were treated with androgenic hormones for endometriosis and compared the results with those of normal control women. Results : The averages of fundamental frequency were 194.7${\pm}$28.2 in study group, 207.0${\pm}$14.1 in control group. The means of closed quotient which were measured with electroglottography were 45.13${\pm}$2.06 in study group, 45.1${\pm}$3.03 in control group. Results of acoustic analysis are as follows. The averages of jitter were 0.95${\pm}$0.46 in study group, 1.10${\pm}$0.65 in control group. The means of shimmer were 2.44${\pm}$0.60 in study group, 2.32${\pm}$1.09 in control group. The averages of noise to harmonic ratio were 0.13${\pm}$0.028 in study group, 0.15$\pm$0.18 in control group. Conclusion : Although there were no statistically meaningful differences between the two groups, we could detect the masculinizing tendency of the therapeutic hormones of endomentriosiss(lowering of fundamental frequency). Given the availability of objective voice assessments today and the continued use of these potent hormones, comprehensive voice assessment and vocal monitoring would appear vital for women commencing hormonal treatment.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.10 no.1
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• pp.43-49
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• 1999

Objectives : The purpose of this study was to systematically analyze and compare e acoustic sound structure of vocal major student's singing voice. Materials and Methods : The nineteen vocal major students were the subject group and healthy nineteen females were the control group for this study. The subject group was taken a strobovideolaryngoscopy by the use of flexible nasopharyngoscopy. And acoustic analysis was taken between two groups. Additionally the inquiry on usual voice problems and management was performed by thirty-six vocal major students. Results : The subject group presents many functional voice disorder findings such as AP contraction(44%), phase difference(36%) tremor(25%), posterior gap(17%), hyperadduction of vestibular fold(6%), and anterior gap(3%) on strobovideolaryngoscopy. And the vocal major students did reveal an enhanced number of high frequency harmonic partials when singing compared to the control group in the narrow band spectrum study. But there was no significant difference in jitter, shimmer and noise to harmonic ratio in both groups. Almost all vocal major students present a lot of voice problems in singing such as loss of high note(17%), loss of quiet voice(17%), effortful and tired voice(36%) etc on inquiry. And they always effort to prevent vocal dysfunction by the use of various type of method such as voice rest(28%), hydration(28%), gargling with salt(11%) etc. Conclusions : The vocal major students always take care of maintaining a good voice condition, but a lot of vocal major students revealed abnormal strobovideolaryngoscopic findings and they are absent in the conception of systemic and scientific voice management. Therefore, the young singers need a good voice training and voice therapy Program under the good ralationship of laryngologist and voice training teacher.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.15 no.1
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• pp.21-26
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• 2004

Vocal Register Transition(Passaggio) is one of the most important vocal technique for classically trined male singers(tenor). Passaggio is that it bridges the chest register to head register without a noticeable voice break. Vocalist gest the feeling that voice is not locked a particular register. The purpose of this study was to clarify the difference between easy($B_3$) tone and non passaggio(F#_4$) & passaggio(F#_4$). We selected 6 trained singers(tenor), who had more than 12.6 years of experience and were well trained in passaggio technique. Simulataneous measurement was performed frequency(F0), mean flow rate(MFR), intensity(I), and subglottal pressure(Psub) using a phonatory function analyzer(Nagashima) and Closed Quotient(CQ), Jitter, Shimmer, NHR a Electro-glottography(EGG) of Lx. Speech Studio(Laryngogrph Lt, London, UK) and vocal efficiency was calculated by Carroll's method. For the tenor, target tone/a/was measured in three conditions : 1) easy phonation : $B_3$, 2) high tone without passaggio : F#_4$, 3) high tone with passaggio : F#_4$). The results revealed that F0 of the target tones between non-passaggio group and passaggio group were not significantly different though higher is F0, higher is subglottal pressure. And also CQ, MFR, Psub were increased in passagio than nonpssagio but these values were not statistically different. This study concluded that passaggio is the vocal technique to make the same quality of tone between chest register and head register in tenor.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.15 no.1
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• pp.27-30
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• 2004

Background and Objectives : The purpose of the present study is to investigate the effect of vocal hygiene education for the female elementary school teachers. Materials and Method : Thirty healthy female elementary school teachers were enrolled for the study. We provided a vocal hygiene education to the half of them. Voice handicap index and acoustic parameters were measured before and 4 week after the education. The efficacy of vocal hygiene education was analyzed by Wilcoxon Signed-rank test. Results : The vocal hygiene group showed significant improvement both in the subjective and objective data after the education. However, the non-vocal hygiene group failed to show any improvement. In functional score, emotional score, jitter, shimmer, only Junior Class(JC) could find significant after the education. Only low career(LC) could find significant in subjective data. Conclusion : Vocal hygiene education may be useful in reducing vocal misuse and abuse associated with teaching, and can be an effective method to maintain and improve the vocal health of teachers.

• Speech Sciences
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• v.15 no.2
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• pp.131-141
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• 2008

The purpose of this study was to find out the acoustic variation on the pre-and post respiration and oral motor for children with cerebral palsy. Five children with spastic CP at the age of 6 in average were practiced by a caregiver at home each for 25 minutes, in total, 45 times. The sustained of vowel /a/ and vowels /a/, /i/, /u/, /e/, /o/ were recorded on CSL and MDVP and analyzed by acoustic parameters. As a result, the maximum phonation time(MPT) was increased from 2.06 to 6.31 and the formant of vowels(F1, F2, F3) had significant differences in F1(/a, i/), F2(/i.u.o/), and F3(/a/) between the controls and the children with CP in pre-treatment. The total average value of vowels had significant differences between the pre-and post-treatment (p< .05). The energy of vowels had significant differences in the vowels /i, u, e, o/ and the total average value between the pre-and post-treatment(p< .001). The jitter percent, shimmer percent, and noise to harmonic ratio had significant differences between the pre-and post-treatment(p< .05). As the respiration and the oral motor improved MPT, voice quality, and articulation of vowel, and the variation of the formant(F1, F2, F3) showed the changes in the shape of lips, the place and the height of the tongue, the various development of therapy programs and the consistent intervention of treatment is needed for the children with cerebral palsy.

• Phonetics and Speech Sciences
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• v.9 no.3
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• pp.85-91
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• 2017

The present study aimed to investigate the changes of acoustic parameters of the aspirated voice in stroke patients. The eighty-eight subjects diagnosed with cerebro-vascular accident were divided into 32 penetration/aspiration (P/A) and 56 Non-P/A groups according to the videofluroscopic swallowing study (VFSS) results, and 26 control subjects participated. All subjects preformed VFSS and vowel /a/ was recorded three times pre- and post VFSS. Since the variation in the acoustic parameters within a single phonation has been observed, we proposed a delta formula for the acoustic parameters which can reflect the temporal changes of the each parameter in an utterance. We measured from the voice data eight acoustic parameters: fundamental frequency (F0), standard deviation of F0 (F0_SD), Jitter, relative average perturbation (RAP), Shimmer, amplitude perturbation quotient (APQ), harmonic to noise ration (HNR), noise to harmonic ratio (NHR). Then we found parameters which show the meaningful biggest temporal change in an utterance using the suggested delta parameter. Among them, the deltas of shimmer and APQ were significantly different pre- and post VFSS. These deltas of the P/A and the control group were increased after VFSS, while those of the Non-P/A group was descended. The variation patterns of the P/A and the control group were similar but the change width of the P/A group was larger. The large variations in an aspirated phonation of the P/A group are thought to be caused by irregular changes in air resistance due to residual food on the vocal cords.