• Fire Science and Engineering
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• v.33 no.1
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• pp.130-137
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• 2019

In this study, the acoustic characteristics of 13 types of emergency broadcasting speakers were tested under the test set-up of UL 2043 and compared. When the sound pressure level of 1 W speakers was compared with speakers with a 15 W output, the SPL of the 15 W speakers was approximately 20 dB higher in some frequency bands. Loudness analysis showed that people can recognize emergency sound from a 15 W speaker twice as loud as the emergency sound from 1 W speakers. The analysis results on the articulation index (room) had an opposite tendency with loudness results, meaning that small speakers can generate clearer sound. Therefore, it is necessary to improve emergency broadcasting speakers to generate louder and clearer sound. Moreover, a performance evaluation standard is needed based on the reasonable and quantitative measurements and evaluations of the acoustic characteristics of the emergency-broadcasting speakers so that a sufficient and clear sound can be generated in various spaces. In addition, it is necessary to establish standards for the clarity of emergency broadcasting in various spaces.

• Phonetics and Speech Sciences
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• v.4 no.3
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• pp.143-149
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• 2012

The purpose of this study is to investigate the speech rate of an esophageal speech group that is capable of vocalization after surgery. The subjects in this experiment were 10 male esophageal speakers and 10 male laryngeal speakers. Each group read a reading passage that was recorded by a DAT recorder (Rolando, EDIROL R-09). These records were analyzed by using CSL (Computerized Speech Lab, model 4150). The results were as follows: (1) the overall speech rate of esophageal speech was 2.50 SPS (syllable per second) while the overall speech rate of laryngeal speech was 4.23 SPS. (2) The articulatory rate of esophageal speech was 3.14 SPS (syllable per second) while the articulatory rate of laryngeal speech was 4.75 SPS. Speech rates as well as articulatory rates of esophageal speech were significantly lower than laryngeal speech. These differences between the two groups may be due to reduced efficiency of airflows across the pharyngeal-esophageal segment for esophageal speakers when compared to airflow through the glottis for laryngeal speakers. These results would provide a guideline in speech rates for esophageal speakers in clinical settings.

• Phonetics and Speech Sciences
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• v.4 no.3
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• pp.3-12
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• 2012

The primary goal of the current study was to examine category solidity of Korean alveolar fricatives in the Busan and Seoul dialects of Korean. Considering the common belief of $/s^h/-/s^*/$ neutralization in Kyungsang speech, plain $/s^h/$ and fortis $/s^*/$ fricatives of Busan speakers were examined against the same fricatives of Seoul speakers. Perceptual distance between Korean $/s^h/$ and $/s^*/$ on the one hand and English /s/ on the other was investigated by use of across-linguistic mapping method. Two experiments of a perceptual mapping task of English /s/ to Korean $/s^h/$ and $/s^*/$ and a $/s^*/$-production task were conducted on users of the Busan and Seoul dialects of Korean. The results from the perception and production experiments suggested that at a micro-level, younger Busan speakers have less solid category stability for Korean $/s^*/$ compared with Seoul speakers, although their production of $/s^h/$ and $/s^*/$ was as highly distinctive from each other as that of Seoul speakers.

• Phonetics and Speech Sciences
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• v.2 no.3
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• pp.47-63
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• 2010

This study provides a description of the glottal characteristics of the word-initial low vowels /a, $\ae$/ in terms of a set of acoustic parameters and discusses glottal configuration as their acoustic correlates. Furthermore, it examines the effect of prosodic boundary on the glottal properties of the vowels, seeking an account of the possible role of prosodic structure based on prosodic theory. Acoustic parameters reported to indicate glottal characteristics were obtained from the measurements made directly from the speech spectrum on recordings of Korean and English collected from 45 speakers. They consist of two separate groups of native Korean and native English speakers, each including both male and female speakers. Based on the three acoustic parameters of open quotient (OQ), first-formant bandwidth (B1), and spectral tilt (ST), comparisons were made between the speech of males and females, between the speech of native Korean and native English speakers, and between Korean and English produced by native Korean speakers. Acoustic analysis of the experimental data indicates that some or all glottal parameters play a crucial role in differentiating the speech groups, despite substantial interspeaker variations. Statistical analysis of the Korean data indicates prosodic strengthening with respect to the acoustic parameters B1 and OQ, suggesting acoustic enhancement in terms of the degree of glottal abduction and the glottal closure during a vibratory cycle.

• Phonetics and Speech Sciences
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• v.8 no.4
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• pp.31-38
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• 2016

The purpose of the current study was to examine the acquisition of the second language prosody by Korean learners of English. Specifically, this study investigated Korean learners' patterns of prosodic phrasing and their use of edge tones (i.e., phrase accents and boundary tones) in English, and then compared the patterns with those of native English speakers. Eight Korean learners and 8 native speakers of English read 5 different English passages. Both groups' patterns of tones and prosodic phrasing were analyzed using the Mainstream American English Tones and Break Indices (MAE_ToBI) transcription conventions. The results indicated that the Korean learners chunked their speech into prosodic phrases more frequently than the native speakers did. This frequent prosodic phrasing pattern was especially noticeable in sentence-internal prosodic phrases, often where there was no punctuation mark. Tonal analyses revealed that the Korean learners put significantly more High phrase accents (H-) on their sentence-internal intermediate phrase boundaries than the native speakers of English. In addition, compared with the native speakers, the Korean learners used significantly more High boundary tones (both H-H% and L-H%) for the sentence-internal intonational phrases, while they used similar proportion of High boundary tones for the sentence-final intonational phrases. Overall, the results suggested that Korean learners of English successfully acquired the meanings and functions of prosodic phrasing and edge tones in English as well as that they are able to efficiently use these prosodic features to convey their own discourse intention.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.1
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• pp.76-82
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• 2005

Speech signal has various features of speakers. This feature is extracted from speech signal processing. The speaker is identified by the speaker identification system. In this paper, we propose the speaker identification system that uses the incremental learning based on neural network. Recorded speech signal through the microphone is blocked to the frame of 1024 speech samples. Energy is divided speech signal to voiced signal and unvoiced signal. The extracted 12 orders LPC cpestrum coefficients are used with input data for neural network. The speakers are identified with the speaker identification system using the neural network. The neural network has the structure of MLP which consists of 12 input nodes, 8 hidden nodes, and 4 output nodes. The number of output node means the identified speakers. The first output node is excited to the first speaker. Incremental learning begins when the new speaker is identified. Incremental learning is the learning algorithm that already learned weights are remembered and only the new weights that are created as adding new speaker are trained. It is learning algorithm that overcomes the fault of neural network. The neural network repeats the learning when the new speaker is entered to it. The architecture of neural network is extended with the number of speakers. Therefore, this system can learn without the restricted number of speakers.

• Phonetics and Speech Sciences
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• v.5 no.4
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• pp.91-98
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• 2013

This study investigates the difference in the evaluation of foreign-accentedness of English pronunciation across subject groups, evaluated accents, and compared components. This study independently evaluates the prosody and segmentals of the foreign-accented English sentences by pairwise difference rating. Using the prosody swapping technique, segmentals and prosody of the English sentences read by native speakers of American English (one male and one female) were combined with the corresponding segmentals and prosody of the English sentences read by male and female native speakers of Chinese, Japanese or Korean (one male and one female from each native language). These stimuli were evaluated by 4 different subject groups: native speakers of American English, Korean, Chinese, and Japanese. The results showed that the Japanese subject group scored higher in prosody difference than in segmental difference while the other groups scored the other way around. This study is significant in that the attitude toward the difference in segmentals and prosody of the foreign accents of English varies with the native language of the subject group. In other words, for native speakers of some languages, the difference in prosody could have a greater influence on the foreign-accentedness than the difference in segmentals, while for native speakers of other languages the other way around.

• Phonetics and Speech Sciences
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• v.5 no.4
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• pp.33-41
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• 2013

This study investigated the perceptual and cepstral/spectral characteristics of phonation and their relationships in dysarthria in connected speech. Twenty-two participants were divided into two groups; the eleven dysarthric speakers were paired with matching age and gender healthy control participants. A perceptual evaluation was performed by three speech pathologists using the GRBAS scale to measure the cepstrual/spectral characteristics of phonation between the two groups' connected speech. Correlations showed dysarthric speakers scored significantly worse (with a higher rating) with severities in G (overall dysphonia grade), B (breathiness), and S (strain), while the smoothed prominence of the cepstral peak (CPPs) was significantly lower. The CPPs were significantly correlated with the perceptual ratings, including G, B, and S. The utility of CPPs is supported by its high relationship with perceptually rated dysphonia severity in dysarthric speakers. The receiver operating characteristic (ROC) analysis showed that the threshold of 5.08 dB for the CPPs achieved a good classification for dysarthria, with 63.6% sensitivity and the perfect specificity (100%). Those results indicate the CPPs reliably distinguished between healthy controls and dysarthric speakers. However, the CPP frequency (CPP F0) and low-high spectral ratio (L/H ratio) were not significantly different between the two groups.

• Phonetics and Speech Sciences
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• v.5 no.4
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• pp.201-207
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• 2013

This study is a follow-up study of Han and Kang (2013) and Kang and Han (2013) which examined cross-generational changes in the Korean vowels /o/ and /u/ using acoustic analyses of the vowel formants of these two vowels, their Euclidean distances and the overlap fraction values generated in SOAM 2D (Wassink, 2006). Their results showed an on-going approximation of /o/ and /u/, more evident in female speakers and non-initial vowels. However, these studies employed non-words in a frame sentence. To see the extent to which these two vowels are merged in real words in spontaneous speech, we conducted an acoustic analysis of the formants of /o/ and /u/ produced by two age groups of female speakers while reading a letter sample. The results demonstrate that 1) the younger speakers employed mostly F2 but not F1 differences in the production of /o/ and /u/; 2) the Euclidean distance of these two vowels was shorter in non-initial than initial position, but there was no difference in Euclidean distance between the two age groups (20's vs. 40-50's); 3) overall, /o/ and /u/ were more overlapped in non-initial than initial position, but in non-initial position, younger speakers showed more congested distribution of the vowels than in older speakers.

• Phonetics and Speech Sciences
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• v.9 no.1
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• pp.27-39
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• 2017

This paper deals with how speech rate in Korean is affected by the sociolinguistic factors such as region, gender and generation. Speech rate was quantified as articulation rate (excluding physical pauses) and speaking rate (including physical pauses), both expressed as the number of syllables per second (sps). Other acoustic measures such as pause frequency and duration were also examined. Four hundred twelve subjects were chosen from Korean Standard Speech Database considering their age, gender and region. The result shows that generation has a significant effect on both speaking rate and articulation rate. Younger speakers produce their speech with significantly faster speaking rate and articulation rate than older speakers. Mean duration of total pause interval and the total number of pause of older speakers are also significantly different to those of younger speakers. Gender has a significant effect only on articulation rate, which means male speakers' speech rate is characterized by faster articulation rate, longer and more frequent pauses. Finally, region has no effect both on speaking and articulation rates.