• 말소리와 음성과학
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• 제1권3호
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• pp.19-28
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• 2009

This paper reports experimental findings about the duration feature of the acoustic components of English stops in Korean speakers' voicing perception. In our experiment, 35 participants discriminated between recorded stimuli and digitally transformed stimuli with different duration features from the original stimuli. 72 sets of paired stimuli are generated to test the effects of the duration feature in various phonetic contexts. The result of our experiment is a complicated cross-tabulation with 540 cells defined by five categorical independent variables plus one response variable. To find a meaningful generalization out of this complex frequency table, we ran logit log-linear regression analyses. Surprisingly, we have found that there is no single effect of the duration feature in all phonetic contexts on Korean speakers' perception of the voicing contrasts of English stops. Instead, the logit log-linear analyses reveal that there are interaction effects among phonetic contexts (=C), the places of articulation of stops (=P), and the voicing contrast (=V), and among duration (=T), phonetic contexts, and the places of articulation. To put it in mathematical terms, the distribution of the data can be explained by a simple log-linear equation, logF=${\mu}+{\lambda}CPV+{\lambda}TCP$.

• 대한음성학회지:말소리
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• 제60호
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• pp.1-11
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• 2006

This paper investigated AV benefit of Korean and Japanese EFL learners' perception of the liquid contrast in English. In a perception experiment, the two English consonants /l/ and /r/ were embedded in initial and medial position in nonsense words in the context of the vowels /i, a, u/. Singletons and clusters were included in the speech material. Audio and video recordings were made using a total of 108 items. The items were presented to Korean and Japanese learners of English in three conditions: audio-alone (A), visual-alone (V) and audio-visual presentation (AV). The results showed that there was no evidence of AV benefit for the perception of the /l/-/r/ contrast for either Korean or Japanese learners of English. The results suggest that increasing auditory proficiency in identifying a non-native contrast is linked with an increasing proficiency in using visual cues to the contrast.

• 말소리와 음성과학
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• 제14권4호
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• pp.11-17
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• 2022

This study investigates closure durations of Korean stops in terms of laryngeal contrasts, places of articulation, and three positions within words. Twenty-two Korean speakers produced the nonsense words containing Korean stops found in word-initial and word-final positions and between vowels. The statistical results showed that the closure durations differed significantly by laryngeal contrast and place of articulation. In addition, the differences by position within words were marginally significant. The closure durations were in the order of lenis < aspirated < fortis stops by laryngeal contrast, velar < alveolar < bilabial stops by place of articulation, and word-final < word-initial < between vowels by positions within words. The laryngeal contrasts were neutralized in word-final position as per coda neutralization in Korean phonology. This study shows that closure durations should be considered a valuable phonetic cue to identify stops on par with voice onset time and f0.

• 말소리와 음성과학
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• 제9권3호
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• pp.57-65
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• 2017

The current study explored how Korean-speaking children processed the multiple acoustic cues (VOT and f0) for the stop laryngeal contrast (/t'/, /t/, and /$t^h$/) and examined whether individual perceptual strategies could be related to a general cognitive ability performing executive functions (EF). 15 children (aged from 7 to 8) participated in the speech perception task identifying the three Korean laryngeal stops (3AFC) on listening to the auditory stimuli of C-/a/ with synthetically varying VOT and f0. They completed a series of EF tasks to measure working memory, inhibition, and cognitive shifting ability. The findings showed that children used the two cues in a highly correlated manner. While children utilized VOT consistently for the three laryngeal categories, their use of f0 was either reduced or enhanced depending on the phonetic categories. Importantly, the children's processing strategies of a f0 suppression for a tense-aspirated contrast were meaningfully associated with children's better cognitive abilities such as working memory, inhibition, and attentional shifting. As a preliminary experimental investigation, the current research demonstrated that listeners with inefficient processing strategies were poor at the EF skills, suggesting that cognitive skills might be responsible for developmental variations of processing sub-phonemic information for the linguistic contrast.

• 융합신호처리학회논문지
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• 제15권2호
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• pp.24-29
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• 2014

X-선 유방촬영술은 유방암의 조기발견을 위해 가장 일반적으로 이용되고 있다. 유방암의 조기 발견과 진단의 효율성을 증가시키기 위하여 많은 영상향상 방법들이 연구개발 되었다. 본 논문은 디지털 맘모그램을 위하여 라플라시안 피라미드에서 대비척도를 이용한 다중 스케일 대비 향상 방법을 제안한다. 제안한 방법은 입력 영상을 가우시안 피라미드와 라플라시안 피라미드로 분해하고, 분해된 다해상도 영상의 피라미드 계수들은 저주파수 성분들과 고주파수 성분들의 비율로 대역 제한된 국부 대비척도를 정의한다. 대비 향상을 위하여 정의된 대비척도를 이용하여 분해된 피라미드 계수들을 수정하고, 수정된 계수들로 피라미드 복원 과정을 거처 최종 향상된 영상을 얻는다. 제안된 방법의 성능은 실험을 통하여 기존 방법들과 향상결과를 비교하고, 대비 측정 알고리즘을 이용한 정량적인 평가결과에서 우수한 성능을 확인하였다.

• 음성과학
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• 제1권
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• pp.83-101
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• 1997

This paper aims at exploring a putative positional neutralization produced at the phonetics/phonology interface. It was designed to determine whether Korean intervocalic laryngeal consonants are phonetically distant from geminates, plain consonants, or laryngeal consonants in consonant clusters. It was found that the contrast between laryngeal singletons and geminates was neutralized intervocalically, and that both of these were patterned with heteroganic consonant sequences rather than with plain singletons.

• 말소리와 음성과학
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• 제1권4호
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• pp.17-27
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• 2009

Despite many studies on the production and perception of L2 phonemes, studies on how such phonemes are encoded lexically remain scarce. The aim of this study is to examine whether L2 learners have a perceptual problem with L2 suprasegmentals which are not present in their L1, or if they are able to perceive but not able to encode them in their lexicon. Specifically, Korean learners were tested to see if they could discriminate the vowel length differences in Japanese at the psychoacoustic level through a simple AX discrimination task. Then, a speeded lexical decision task with high phonetic variability was conducted to see whether they could use such contrasts lexically. The results showed that Korean learners of Japanese have no difficulties in discriminating Japanese vowel length contrast, but they are unable to encode such contrast in their phonological representation, even with long L2 exposure.

• 음성과학
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• 제7권3호
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• pp.53-68
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• 2000

Although Korean stops and affricates show a three-way contrast of phonemes into lax, tense and aspirated, Korean fricatives have only two types, so-called 'lax' and tense. Considering that all the other obstruents maintain a three-way distinction but fricatives, it might be interesting to investigate whether the lax fricatives are really 'lax' in their phonetic and phonological realizations, as assumed. From an acoustic analysis, I found that Korean lax fricatives had a heavy aspiration along with a high pitch for the following vowel, being more comparable to the aspirated category. By contrast, their durational properties were found to be short, or lax-like. In other words, Korean lax fricatives are phonetically neither lax nor aspirated, but both. This dual nature of the lax fricatives takes a better account of the fact that why lax fricatives are subject to tensification, but not aspiration phonologically. Is that simply because there is no aspirated fricative in Korean? I suggest that Korean lax fricatives undergo tensification because of their being short in duration, and that they are not subject to the aspiration rule because they are indeed aspirated sounds.

• 말소리와 음성과학
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• 제15권3호
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• pp.9-16
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• 2023

The current study investigated the influence of age of L2 acquisition (AOA) and length of residence (LOR) in the L2 setting country on the production of voicing-conditioned vowel duration and spectral qualities in English by Korean learners. The primary aim was to explore the ways in which the language-specific phonetic features are acquired by the age of onset and L2 experience. Analyses of the archived corpus data produced by 45 native speakers of Korean showed that, regardless of AOA or LOR, absolute vowel duration was used as a salient correlate of voicing contrast in English for Korean learners. The accuracy of relative vowel duration was influenced more by onset age than by L2 experience, suggesting that being exposed to English at an early age may benefit the acquisition of temporal dimension. On the other hand, the spectral characteristics of English vowels were more consistently influenced by L2 experience, indicating that immersive experience in the L2 speaking environment are likely to improve the accurate production of vowel quality. The distinct influence of the onset age and L2 experience on the specific phonetic cues in L2 vowel production provides insight into the intricate relationship between the two factors on the manifestation of L2 phonological knowledge.

• 한국음향학회지
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• 제22권8호
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• pp.694-702
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• 2003

이 연구는 말장애의 진단에 유용한 일음절 낱말대조 명료도 검사 (낱말명료도)의 타당도와 신뢰도를 얻기 위한 것이다. 첫번째로 낱말명료도의 타당성을 확인하기 위하여 문장명료도와의 상관을 구한 결과 상관은 .83으로 비교적 높았다. 두 번째로는 평가자들 간의 일치도를 분석하였다. 낱말명료도는 명료도 손상의 수준에 상관없이 평가자들간에 일정한 변산을 보였다. 마지막으로 낱말명료도 평가도구를 이용하여 마비말장애인의 명료도를 떨어뜨리는데 주요한 역할을 하는 음소대조 요인을 살펴본 결과 종성이 가장 오류가 많았으며 다음으로 초성, 중성의 순서였으나, 회귀분석 결과 초성이 전체 명료도에 미치는 영향이 가장 컸다.