• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.7 no.1
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• pp.50-55
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• 1996

Acoustic analysis study was performed on 20 normal subjects by speaking nonsense syllables composed of Korean bilabial stops$(/P, P^{\star}, P^{h}/)$ and their preceding and/or following vowel /a/ (that is, $[pa, p^{\star}a, p^{h}a, apa, ap^{\star}a, ap^{h}a]$) with an ultraminiature pressure, sensor. in their mouths. Speech materials were phonated twice, once with a moderate voice, another time with a loud voice. The acoustic signal and intraoral pressure were recorded simultaneously on computer. By these procedures, we were to measure the intraoral pressure, closure duration and VOT of Korean bilabial stops, and to compare the values one another according to the intensity of phonation and the position of the target consonants. Intraoral pressure was measured by the peak intraoral pressure value of Its wave closure duration by the time interval between the onset of intraoral pressure build-up and the burst meaning the release of closure ; Voice onset time(VOT) on by the time interval between the burst and the onset or glottal vibration. Heavily aspirated bilabial stop consonant /$p^h$/ showed the highest intraoral pressure value, unaspirated /$p^{\star}$/, the second, slightly aspirated /P/, the lowest. The syllable initial bilabial stops showed higher intraoral pressure than word initial stops, and the value of loudly phonated consonants were higher than moderate consonants. The longest closure duration period was that of /$p^{\star}$/ and the shortest, /P/, and the duration was longer in word initial position and in the moderate voice. In VOT, the order of the longest to shortest was $/{p^h}/, /p/, /{p^\star}/$, and the value was shorer when the consonant was in intervocalic position and when it was phonated with a loud voice.

• Proceedings of the KSPS conference
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• 2000.07a
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• pp.165-165
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• 2000

In the phoneme level, English stop sounds are classified with the feature of 'voicing': voiceless and voiced (p/b, t/d, k/g). But when realized, a voiceless stop is not alwats the same sound. For example, the two 'p' sounds in 'people' are different. The former is pronounced with much aspiration, while the latter without it. This allophonic differnece between [$P^h$] and [p] out of an English phoneme /p/ can be well explained to Koreans because in Korean these two sounds exist as two different phonemes {/ㅍ/ and /ㅃ/ respectively). But difficulties lie in teaching the English voiced stop sounds (/b, d, g/) to Koreans because in Korean voiced stops do not exist as phonemes but as allophones of lenis sounds (/ㅂ, ㄷ, ㄱ/). For example, the narrow transcription of '바보' (a fool) is [baboo]. In the word initial position, Korean lenis stops are pronounced voiceless and even with a slight aspiration while in the inrervocalic environments they become voiced, That is in Korean voiced stops do not occur independently and neither they have their own letters. To explain all these more effectively to Koreans, it is very helpful to use Korean Phenetic Alphabet (KPA) which is devised by Dr. LEE Hyunbok (a professor of phonetics at Seoul National Univ. and chairman of Phonetic Society of Koera.)(omitted)

• Phonetics and Speech Sciences
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• v.15 no.3
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• pp.45-52
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• 2023

Previous studies have established a role for cognitive differences in explaining variability in speech processing across individuals. In the case of perceptual cue weighting in the context of a sound change, studies have produced conflicting results regarding the relationship between executive function and the use of redundant cues. The current study aimed to explore this relationship in acoustic cue weighting during speech production. Forty-one Korean-speaking children read a list of stop-initial words and completed two tests that assess executive function, i.e., Dimensional Change Card Sorting (DCCS) and digit n-back. Voice onset time (VOT) and fundamental frequency (F0) were measured in each word, and analyses were carried out to determine the extent to which children's executive function predicted their use of both informative and less informative cues to the three pairs comprising the Korean three-way stop laryngeal contrast. No evidence was found for a relationship between cognitive ability and acoustic cue weighting in production, which is at odds with previous, albeit conflicting, results for speech perception. While this result may be due to the lack of task demands in the production task used here, it nevertheless expands the empirical ground upon which future work in this area may proceed.

• Speech Sciences
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• v.11 no.1
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• pp.65-72
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• 2004

The force of articulation is different between voiced and voiceless consonants in the binary opposition system. However, the Korean voiceless stop consonants have a triple opposition system: lenis, aspirated, and glottalized. The aim of this study is to find the primary distinctive feature between the force of articulation and the aspiration for the three different types of Korean stops. Two native speakers of the Seoul dialect participated to this study. The corpus was composed of less than eight syllabic words containing consonants in word-initial position and intervocalic position. Radiocinematography and Mingography were used to analyze the articulatory tension and acoustic characteristics. Korean stops have independent features of articulatory tension and aspiration, in which the indices are different according to position. However, in this system which does not have the opposition of sonority, the force of articulation is the primary distinctive feature and the feature of aspiration is subsidiary.

• MALSORI
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• no.33_34
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• pp.1-10
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• 1997

Korean stop consonants are well known for their tripple distinction. In word initial position lax, tense and aspirated consonants are all voiceless. They are differentiated by the degree of tension, aspiration and VOT(voice onset time). But in intervocalic position, lax consonants become voiced. In this study I compare the acoustic features of Korean intervocalic lax and tense stops. The closure duration of lax stops is shorter than that of tense consonants. The preceding vowel length is longer in tan than that in tense consonants. I modify the above acoustic characteristics by an experimental methods. For example, I shorten the closure duration of intervocalic tense stops by 5 steps. r also do auditory tests which will show us listener's reaction on the above examples. And do the same job with the preceding vowels. According to the auditory test, the closure duration does an important role in differentiating Korean intervocalic lax and tense stops. But the preceding vowel length has almost nothing to do with the distinction between lax and tense stops. So I conclude that acoustic features also have hierarchy. Some features have categorical characteristics and others don't.

• ETRI Journal
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• v.46 no.4
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• pp.633-647
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• 2024

In e-commerce platforms, sentiment analysis on an enormous number of user reviews efficiently enhances user satisfaction. In this article, an automated product recommendation system is developed based on machine and deep-learning models. In the initial step, the text data are acquired from the Amazon Product Reviews dataset, which includes 60 000 customer reviews with 14 806 neutral reviews, 19 567 negative reviews, and 25 627 positive reviews. Further, the text data denoising is carried out using techniques such as stop word removal, stemming, segregation, lemmatization, and tokenization. Removing stop-words (duplicate and inconsistent text) and other denoising techniques improves the classification performance and decreases the training time of the model. Next, vectorization is accomplished utilizing the term frequency-inverse document frequency technique, which converts denoised text to numerical vectors for faster code execution. The obtained feature vectors are given to the modified convolutional neural network model for sentiment analysis on e-commerce platforms. The empirical result shows that the proposed model obtained a mean accuracy of 97.40% on the APR dataset.

• The Journal of the Acoustical Society of Korea
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• v.18 no.7
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• pp.85-91
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• 1999

The purpose of this study is to investigate phonetic realization of flap [r], one of the allophones of Korean /l/. Phonetic realization of a segment is affected by not only its neighboring segments but also its prosodic position in an utterance. This study examined how various prosodic positions affect the phonetic realization of [r]. Effects of the four prosodic positions on the phonetic realization of [r] were examined: utterance initial, Intonation Phrase initial, Accentual Phrase initial, and Accentual Medial positions. Word positional effect was also examined: word initial, medial, and final positions. Acoustic and statistical analyses showed that flap [r] was realized in a variety of phonetic forms: from sonorant(the most reduced form) to short stop(the least reduced form). It was shown that generally. word-initial position is stronger than word-medial position. It was also shown that in many cases, utterance-initial position and intonation-phrase-initial position are stronger than accentual-phrase-initial and accentual-phrase-medial positions. Sonorants were observed more often in the prosodically weaker portions. VOT duration was also shorter in accentual-phrase-initial and accentual-phrase-medial positions.

• Phonetics and Speech Sciences
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• v.2 no.1
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• pp.41-50
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• 2010

The current study exploresacoustic variation induced by prosodic contexts in different speech styles,with a focus on motherese or child-directed speech (CDS). The patterns of variation in the acoustic expression of voicing contrast in English stops, and the role of prosodic factors in governing such variation are investigated in CDS. Prosody-induced acoustic strengthening reported from adult-directed speech (ADS)is examined in the speech data directed to infants at the one-word stage. The target consonants are collected from Utterance-initial and -medial positions, with or without focal accent. Overall, CDS shows that the prosodic prominence of constituents under focal accent conditions variesin the acoustic correlates of the stop laryngeal contrasts. The initial position is not found with enhanced acoustic values in the current study, which is similar to the finding from ADS (Choi, 2006 Cole et al, 2007). Individualized statistical results, however, indicate that the effect of accent on acoustic measures is not very robust, compared to the effect of accent in ADS. Enhanced distinctiveness under focal accent is observed from the limited subjects' acoustic measures in CDS. The results indicate dissimilar strategies to mark prosodic structures in different speech styles as well as the consistent prosodic effect across speech styles. The stylistic variation is discussed in relation to the listener under linguistic development in CDS.

• Korean Journal of English Language and Linguistics
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• v.2 no.1
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• pp.23-30
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• 2002

Phonologically, the difference between the English stops /b, d, g/ and /p, t, k/ is carried by the presence or the absence of the vocal fold vibration throughout their oral closure phase. If phonology has its foundation in phonetics, there must be phonetic evidence for the voiced-voiceless distinction. This study is aimed to determine whether or not the voiced-voiceless distinction is acceptable or proper in English. The determination was based mainly on findings in the existing literature and in informal experiments. In conclusion, there is no phonetic evidence for the voiced-voiceless distinction both in production and perception. The [voice] appears to be one of potential phonetic correlates of the phonologically voiced stop. It is improper to use the [voice] as independent phonological marker, regardless of position (word-initial, intervocalic, word-final). A feature other than the voiced-voiceless feature must distinguish /b, d, g/ from /p, t, k/.

• Phonetics and Speech Sciences
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• v.16 no.1
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• pp.25-31
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• 2024

This study examines the perceptual motivation behind dissimilation. Consistent with previous arguments suggesting that dissimilation originates from perception rather than production (Coetzee, 2005; Kiparsky, 2003; Scheer, 2013), we hypothesized that an oral stop with short of voice onset time (VOT) would be recognized as non-aspirated more often when it is followed by an aspirated stop with a long VOT. This hypothesis was tested through a perception experiment in which 32 Korean listeners made judgments on the first consonant of C₁VC₂V words manipulated with C₁ VOT and C₂ types. The results revealed that aspirated-based C₁ was recognized as aspirated or tense depending on the duration of VOT, while lenis-based C₁ was consistently recognized as lenis. The dissimilatory effect of aspirated C₂ was confirmed as anticipated, and furthermore, tense C₂ increased the ratio of tense responses more than aspirated C₂. These results provide evidence of a perceptual bias against recurrent aspirated stops, which may play a role in activating a dissimilatory rule or constraint in a language. The assimilatory effect of tense C₂ is in consistent with findings indicating that word-initial tensification is facilitated by the following tense stop in Korean (Kang & Oh, 2016; H. Kim, 2016).