• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.3
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• pp.10-17
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• 1996

The performance of tau-dither loop (TDL) is evaluated for a direct-sequence spread-spectrum system in a multipath fading channel. The multipath fading channel is modeled as a two-ray rayleight fading channel. The code tracking perfomrance of TDL is analyzed in terms of tracking jitter and mean-tiem-to-lose-lick (MTLL). The tracking jitter performance is degraded while MTLL perfomrance is improved with increasing discriminator offset and decreasing power ratio of main to second paths. It is shown that for a large bit SNR, the effect of multipath fading becomes more significant. And it is also shown that tracking jitter and MTLL performance is less sensitive to delay spacing and discriminator offset for a small bit SNR than for a large bit SNR.

• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.215-218
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• 2003

A 2R O/E/O wavelength converter is useful for bit rate transparency, though it has a limit on cascadability due to timing-jitter accumulation. In this paper, we propose a nonlinear signal model which is more practical than the commonly used sine wave model. With our model, we theoretically analyzed the effects of timing-jitter and the cascadability of a 2R O/E/O wavelength converter. To confirm the theoretical results, we measured the cascadability in a 40-km re-circulation loop for 10 Gb/s signal.

• Proceedings of the IEEK Conference
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• 2001.06c
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• pp.93-96
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• 2001

In this paper, we propose a delay-constrained retransmission method to control packet error or loss in common internet. The Delay Regulator(or Jitter Buffer) which is used to control errors caused by unreliable UDP connection, stores received data packets fDr a small amount of time to prevent network jitter from affecting display quality, which causes constant delay. In this paper, we propose a retransmission method to increase efficiency of ARQ(Automatic Repeat reQuest) by using characteristic of delay regulator.

• Journal of the Korean Mathematical Society
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• v.47 no.6
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• pp.1299-1316
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• 2010

We derive estimates for the truncation, amplitude and jitter type errors associated with Hermite-type interpolations at equidistant nodes of functions in Paley-Wiener spaces. We give pointwise and uniform estimates. Some examples and comparisons which indicate that applying Hermite interpolations would improve the methods that use the classical sampling theorem are given.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.16 no.2
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• pp.140-145
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• 2005

Background and Objectives : Voice perturbation measures, such as jitter and shimmer has been importantly used for diagnosis and treatment efficacy of laryngeal dysfunction. This study was conducted to investigate validity of newly developed multi-channel voice analyzer program by comparing with MDVP, PRAAT, TF32. In addition, we compared the voice perturbation measures with different voice analyzer program by type of signals. Materials and Methods : Nineteen mild-severe dysphonic patients participated in our study. Fundamental frequency, jitter and shimmer values were obtained from different voice analyzer program using the same sustained/ah/phonation. Results : Fundamental frequency and shimmer were highly correlated whereas jitter was weakly correlated between newly developed multi-channel voice analyzer program and the others though different pitch computation algorithm except MDVP, In addition, Type 2 and 3 signals were weakly correlated than Type 1. Conclusion : In the clinical setting, clinician may have sufficient information of voice analyzer and control conditions properly for severity of pathologic voice before voice perturbation measure to obtain reliable results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10A
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• pp.877-885
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• 2005

The Home Phoneline Networking Alliance (HomePNA) 2.0 technology can establish a home network using existing in-home phone lines, which provides a channel rate of 4-32 Mbps. HomePNA 2.0 Medium Access Control(MAC) protocol adopts an IEEE 802.3 Carrier Sense Multiple Access with Collision Detection (CSMA/CD) access method, Quality of Service(QoS) algorithm, and Distributed Fair Priority Queuing(DFPQ) collision resolution algorithm. In this paper, we propose some mathematical models about the important elements of HomePNA 2.0 MAC protocol performance, which are Saturation Throughput, Packet Delay and Packet Jitter. Then, we present an overall performance analysis of HomePNA 2.0 MAC protocol along with simulations.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.19 no.2
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• pp.123-127
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• 2008

Background and Objectives: Smoking has been identified as one of the main determinants of negative changes on the larynx histology. The purpose of this study is to investigate the voice characteristics and correlation between voice parameters of the smokers with vocal polyp or nodule or both of them. Materials and Method: MPT, $F_0$, jitter, shimmer, NHR of Korean /a/ vowel from 54 smokers and 50 nonsmokers diagnosed as vocal polyp or nodule were analyzed. A Computerized Speech Lab (4400) was for the analysis of each voice sample and statistical analysis was done by one-way ANOVA and Pearson correlation coefficient. Result and Conclusion: It showed that we can find difference between smokers and nonsmokers group in MPT, $F_0$, jitter, shimmer were different except NHR. each group shows difference in correlation coefficient between MPT, $F_0$, jitter, shimmer.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.5 no.3 s.11
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• pp.13-23
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• 2006

The system using UWB is processing brisk study with Bluetooth among the wireless access that is major technology in Telematics. The low complexity and cost for realization is advantage of UWB have communication of high speed. Mamy papers have published on the timing jitter effect on system performance except for the UWB system. In this paper, we analyze the effect of timing jitter on M-ary UWB system using orthogonal Hermite pulse and perform the simulation to show symbol error rate performance. For theoretical analysis, we derive correlation function of orthogonal Hermits pulse with closed form, and as well upper bound of Symbol Error Probability for M-ary orthogonal Hermite pulse system mathematically. It is found that numerical analysis is accurate enough through simulation.

• Phonetics and Speech Sciences
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• v.7 no.4
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• pp.85-92
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• 2015

This study aimed to establish characteristics related to voice and speech through the natural base frequency analysis of esophagus vocalization. In the study, 8 subjects were selected for esophagus vocals, and 10 other subjects were selected for a control group. MDVP(Multi-dimensional Voice Program, Model 4800, USA, 2001), Multi Speech(Model 3700, Kaypantax, USA, 2008) were used as experiment equipment. The speech samples selected for evaluation were vowels and sentences (both declarative and interrogative). For acoustic analysis, the intonation form of fo, jitter, energy, shimmer, HNR, and intonation patterns of the speech sample were measured. The results were as follows: First, the natural intrinsic frequency of extended vowels in the esophagus vocal group was lower than the frequency in the normal vocal group. In particular, the intrinsic frequency difference for high vowel /i/ was much greater than the frequency difference for low vowel /a/. Second, the jitter values of the esophagus vocal group were higher than the control group. In particular, there was a large difference between the jitter values for /a/ and /i/, with the jitter values being highest for /i/. Third, there was no significant difference in vocal strength between the esophagus vocal patient group and the control group. Fourth, the shimmer values of the voices in the esophagus vocal group were higher than shimmer values in the control group. In particular, there was a large difference in shimmer values for low vowel /a/. Fifth, the HNR values of the esophagus vocal group were showed significantly lower than the control group. In particular, the largest difference in HNR values between the two groups was for high vowel /i/. Sixth, the pitch contours of interrogative and declarative sentences of the esophagus vocal patient group showed a different form or only had with small differences compared to the pitch contours of the normal vocal group, thus presenting an inconsistent pattern.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7B
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• pp.834-840
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• 2011

Chronic diseases is being increased attention to threatening the elements healthy life of elderly population in modem society. Especially, Chronic diseases caused by diabetes and hypertension is destroyed kidney. In this case, subjective symptom is not little. So if health is worsened, hemodialysis, artificial organs, transplant an organ etc. should be treated as a dangerous diseases. Therefor, a patients receiving hemodialysis of diabetes and hypertension studied on the effects to regularity of amplitude and rate vibration of vocal cords in hemodialysis in this paper. To do this, a diabetic and hypertensive patients don't have a problem with pronunciation selected as of the subjects and their voices collected before and after hemodialysis. We studied on the effects of voice analysis to apply regularity of amplitude and rate vibration of vocal cords. In conclusion, we extracted a result that voice after than before hemodialysis is relatively low in voice measures values a regularity of amplitude and rate vibration of vocal cords.