• The Journal of the Acoustical Society of Korea
• /
• v.23 no.1
• /
• pp.61-74
• /
• 2004

In this paper, a contort- and speaker-dependent cepstrum extraction method and a channel normalization method for minimizing the loss of speaker characteristics in the cepstrum were proposed for a robust speaker recognition system over the channel. The proposed extraction method creates a cepstrum based on the pitch synchronous analysis using the inherent pitch of the speaker. Therefore, the cepstrum called the 〃pitch synchronous cepstrum〃 (PSC) represents the impulse response of the vocal tract more accurately in voiced speech. And the PSC can compensate for channel distortion because the pitch is more robust in a channel environment than the spectrum of speech. And the proposed channel normalization method, the 〃formant-broadened pitch synchronous CMS〃 (FBPSCMS), applies the Formant-Broadened CMS to the PSC and improves the accuracy of the intraframe processing. We compared the text-independent closed-set speaker identification on 56 females and 112 males using TIMIT and NTIMIT database, respectively. The results show that pitch synchronous km improves the error reduction rate by up to 7.7% in comparison with conventional short-time cepstrum and the error rates of the FBPSCMS are more stable and lower than those of pole-filtered CMS.

• Speech Sciences
• /
• v.12 no.2
• /
• pp.17-28
• /
• 2005

This paper argues that news speech entails a distinct intonational pattern from natural speech, effectively reflecting that it primarily focuses on providing new information. We conducted a phonetic experiment to compare the tonal contours between news speech and natural speech, examining the distributions of pitch accents and the overall pitch ranges. We utilized 70 American Press (AP) radio news utterances and 70 natural utterances extracted from TV dramas. Results show that news speech involves 3.38 H*'s (including L+H* and !H*) within an intonational phrase (IP) or intermediate phrase (ip) whereas natural speech, 1.8 in average. The number of IP/ip's per sentence is 3 in news speech, which is shown in the highest rate of 32.07% of the news speech, but it is merely 1, taking up the highest 41.42% in natural speech. Next, declination tends to be prevented in news speech, and the pitch range is much greater in news speech than in natural speech. Finally, a secondary stress syllable is comparatively frequently given a pitch accent in news speech, explicitly distinct from natural speech. These results can be interpreted as stating that news has the particular purpose of providing new information; every content word tends to be given a H* or its related pitch accent like L+H* or !H* because news speech assumes that every word conveys new information. This definitely brings about more IP/ip's per sentence due to a human physiological constraint; that is, more H*'s will cause more respiratory breaks. Also, greater pitch ranges and pitch accents imposed on secondary stress may be attributed to exaggerating new information.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.47 no.5
• /
• pp.100-108
• /
• 2010

An autocorrelation method is used in pitch estimation. Autocorrelation values in time and frequency domains, which have different characteristics, correspond to the pitch period and fundamental frequency, respectively. We utilize an integrated autocorrelation method in time and frequency domains. It can remove the errors of pitch doubling and having. In the time and frequency domains, pitch period and fundamental frequency have reciprocal relation to each other. Especially, fundamental frequency estimation ends up as an error because of the resolution of FFT. To reduce these artifacts, interpolation methods are applied in the integrated autocorrelation domain, which decreases pitch errors. Moreover, only for the pitch candidates found in a time domain, the corresponding frequency-domain autocorrelation values are calculated with reduced computational complexity. Using linear interpolation, we can decrease the required number of FFT coefficients by 8 times. Thus, compared to the conventional methods, computational complexity can be reduced by 9.5 times.

• Proceedings of the KIEE Conference
• /
• 2002.07b
• /
• pp.961-963
• /
• 2002

When high temperature superconducting(HTS) tapes are wound on former for HTS cable application, their critical characteristics are likely to be degraded seriously because of mechanical stress. In this study, prior to fabricate prototype HTS cables, we investigated the variation of critical characteristics of HTS tapes according to their pitch angles. For this work, we prepared the samples of HTS tapes on the former of which diameter is 3cm. Pitch angles of HTS tapes are $0^{\circ}$, $00^{\circ}$, $20^{\circ}$, $30^{\circ}$, $40^{\circ}$, respectively. We applied current up to 160 $A_{rms}$ to HTS tapes and investigated E-I characteristics. The critical current of HTS tapes was decreased as pitch angle increased. In addition, when the applied current was beyond their critical current, the rate of resistance increase of HTS tapes was in proportion to their critical current. Finally, We concluded that the pitch angles affected resistance increase of HTS tapes as well as critical current.

• Speech Sciences
• /
• v.7 no.2
• /
• pp.139-155
• /
• 2000

The aim of this research is to investigate acoustic characteristics of three different types of Korean Stops-plain, tensed, and aspirated-, and employ these as a base to determine which one(s) can be used as perceptual cues. In this paper, we have examined acoustic characteristics of Korean Stops, especially voice onset time(VOT), closure duration(CD), degree of pitch of following vowels and differences in the intensity of the Stops build-up after the onset of voicing. From the above characteristics, differences can be made between word-initial and word-medial positions. That is to say, in word-initial position, the three Korean Stops are distinguished by VOT and pitch, whereas in word-medial by CD, VOT and pitch. However, the acoustic characteristics do not have the same value as perceptual cues. In both word-initial, and medial positions, the immediately following vowels play the most important role in perceiving Korean Stops. And in case of word'-medial positions,. CD and VOT also play important perceptual roles. In order to have a more fine-grained distinction among Korean Stops, we think future research should be done to investigate which factor(s) of the following vowels is/are the most determinative perceptual cue(s). However, based on our investigation, we may conclude that it is highly plausible that pitch can be one of the most important perceptual cues when distinguishing the three Korean Stops.

• Carbon letters
• /
• v.3 no.1
• /
• pp.13-16
• /
• 2002

The modification of coal-tar pitch has been carried out by heat treatment of pitch at different temperatures in the range ($300^{\circ}-400^{\circ}C$) for different times (2-5 hrs) in air and nitrogen. The pitch heat treated in air at lower temperature ($300^{\circ}C$) exhibit increase in softening point by $20^{\circ}C$ as compared to only $2^{\circ}C$ when treated in nitrogen. The changes are faster in air than in pure nitrogen. Pitch as such as well as after heat treatment were further treated with metal complexes by solution route. Silver intake has been found to increase from 0.5 to 0.8 % in nitrogen treated pitch while the uptake is found to decrease for pitches treated in air at $350^{\circ}C$ for 5 hrs. Experiments have also been made to incorporate silver into PAN and PAN-ox fibers through solution route. The metal intake has been found to be more in PAN-ox fibers than in PAN as such. Metal loaded carbon composites have been made by using metal loaded fibers as well as cokes. These composites as such exhibit higher surface oxygen complexes but decrease after activation.

• Carbon letters
• /
• v.1 no.1
• /
• pp.22-26
• /
• 2000

Raman spectroscopy has been used to investigate the structure of coal tar pitch heat-treated up to $3000^{\circ}C$ by using 514.5 run Ar ion laser line. Four critical temperature ranges were found on pyrolyzing coal tar pitch, which correspond to four distinct processes from disordered carbons to the well-ordered graphite structure. The range of heat treat temperature (HTT) below $1000^{\circ}C$ corresponds to gas evolution during the pyrolysis of coal tar pitch. Above the HTT are correlated to rearrangements of enlarged molecules, growth of the molecules along the direction of plane, finally stacking in the normal direction of the plane, in the respective HTT ranges of 1000-2000, above 2000 and $2500-3000^{\circ}C$.

• The Journal of Korean Society for Radiation Therapy
• /
• v.30 no.1_2
• /
• pp.201-208
• /
• 2018

Purpose : The purpose of this study is to compare and analyze the set-up errors using the Combine IGRT with ExacTrac and CBCT phased in the treatment of Stereotatic Body Radiotherapy. Methods and materials : Patient who were treated Stereotatic Body Radiotherapy in the ulsan university hospital from May 2014 to november 2017 were classified as treatment area three brain, nine spine, three pelvis. First using ExacTrac Set-up error calibrated direction of Lateral(Lat), Longitudinal(Lng), Vertical(Vrt), Roll, Pitch, Yaw, after applied ExacTrac moving data in addition to use CBCT and set-up error calibrated direction of Lat, Lng, Vrt, Rotation(Rtn). Results : When using ExacTrac, the error in the brain region is Lat $0.18{\pm}0.25cm$, Lng $0.23{\pm}0.04cm$, Vrt $0.30{\pm}0.36cm$, Roll $0.36{\pm}0.21^{\circ}$, Pitch $1.72{\pm}0.62^{\circ}$, Yaw $1.80{\pm}1.21^{\circ}$, spine Lat $0.21{\pm}0.24cm$, Lng $0.27{\pm}0.36cm$, Vrt $0.26{\pm}0.42cm$, Roll $1.01{\pm}1.17^{\circ}$, Pitch $0.66{\pm}0.45^{\circ}$, Yaw $0.71{\pm}0.58^{\circ}$, pelvis Lat $0.20{\pm}0.16cm$, Lng $0.24{\pm}0.29cm$, Vrt $0.28{\pm}0.29cm$, Roll $0.83{\pm}0.21^{\circ}$, Pitch $0.57{\pm}0.45^{\circ}$, Yaw $0.52{\pm}0.27^{\circ}$ When CBCT is performed after the couch movement, the error in brain region is Lat $0.06{\pm}0.05cm$, Lng $0.07{\pm}0.06cm$, Vrt $0.00{\pm}0.00cm$, Rtn $0.0{\pm}0.0^{\circ}$, spine Lat $0.06{\pm}0.04cm$, Lng $0.16{\pm}0.30cm$, Vrt $0.08{\pm}0.08cm$, Rtn $0.00{\pm}0.00^{\circ}$, pelvis Lat $0.06{\pm}0.07cm$, Lng $0.04{\pm}0.05cm$, Vrt $0.06{\pm}0.04cm$, Rtn $0.0{\pm}0.0^{\circ}$. Conclusion : Combine IGRT with ExacTrac in addition to CBCT during Stereotatic Body Radiotherapy showed that it was possible to reduce the set-up error of patients compared to single ExacTrac. However, the application of Combine IGRT increases patient set-up verification time and absorption dose in the body for image acquisition. Therefore, depending on the patient's situation that using Combine IGRT to reduce the patient's set-up error can increase the radiation treatment effectiveness.

• Proceedings of the KSPS conference
• /
• 2003.10a
• /
• pp.181-184
• /
• 2003

This paper explores the perceptual relevance of acoustical correlates of emotional speech by using formant synthesizer. The focus is on the role of mean pitch, pitch range, speed rate and phonation type when it comes to synthesizing emotional speech. The result of this research is backing up the traditional impressionistic observations. However it suggests that some phonation types should be synthesized with further refinement.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.2
• /
• pp.162-169
• /
• 2011

The flight control system utilize RSS(Relaxed Static Stability) criteria in both longitudinal axes to achieve performance enhancements and improve stability. The aircraft using digital flight-by-wire flight control system receives aircraft flight conditions such as pitch, roll and yaw rate, normal acceleration from RSA(Rate Sensor Assembly) and ASA(Acceleration Sensor Assembly). These sensors has permissible measurement error related to system safety of an aircraft but, unexpected flight motions are happened by sensing errors such as offset, noise and etc. The unexpected pitch down tendency occurred by ASA sensor bias in 1g level flight with pilot hands-off. This paper addresses the design and verification of flight control law to improve of pitch down or up tendency caused by ASA sensor bias. The result of analysis and flight test reveals that pitch down tendency can be improved by pitch attitude feedback system.