• Speech Sciences
• /
• v.4 no.1
• /
• pp.47-58
• /
• 1998

This paper tests whether frication duration plays an important role in perceiving fricatives and affricates. In other words, whether the frication duration is an acoustic cue for distinguishing fricatives from affricates. For this purpose two types of experiments are carried out. In the first experiment two sets of stimuli are created by decreasing the frication duration of fricatives by 10ms, and in the second experiment two steps of stimuli are created by increasing the frication duration of affricates by 10 ms. The results of the present study show that frication duration is the primary acoustic cue in perceiving fricative/affricate distinction in Korean. In addition, the amplitude rise time and burst information appear to play secondary roles in perceiving the distinction by a series of perception tests.

• Phonetics and Speech Sciences
• /
• v.1 no.2
• /
• pp.105-110
• /
• 2009

This paper introduces the technique of semi-automatically identifying different types of noise in the frequency domain. Given the lower cutoff frequency of the frication noise, and a user-specified constant, the technique identifies the boundary between the frication and aspiration noise in a Korean lax fricative followed by the vowel /a/ by comparing the upper and lower sums of energy with respect to the cutoff frequency. The user-specified constant can be adjusted for different speakers. When the technique was applied to distinguish the two types of noise of Korean lax fricatives from the same speaker, the average and standard deviation of the difference between the manually inserted boundaries and the automatically inserted boundaries were 2.67ms and 1.80ms respectively.

• Phonetics and Speech Sciences
• /
• v.10 no.3
• /
• pp.41-48
• /
• 2018

This study examined the acoustic characteristics of Korean alveolar fricatives of normal children. Developing children aged 3 and 7, typically produced 2 types of nonsense syllables containing alveolar fricative /sV/ and /VsV/ sequences where V was any one of three corner vowels (/i, a, and u/). Stimuli containing the speech materials used in a production experiment were presented randomly to 12 speech language pathologists (SLPs) for a perception test. The SLPs responded by selecting one of seven alternative sounds. Acoustic measures such as duration of frication noise, normalized intensity, skewness, and center of gravity were examined. There was significant difference in acoustic measures when comparing vowels. Comparison of syllable structures indicated statistically significant differences in duration of frication noise and normalized intensity. Acoustic parameters could account for the perceptual data. Relating the acoustic and perception data by means of logistic regression suggests that duration of frication noise and normalized intensity are the primary cues to perceiving Korean fricatives.

• Tribology and Lubricants
• /
• v.12 no.3
• /
• pp.55-62
• /
• 1996

Present study was undertaken to investigate the effects of composition ratio and temperature on the friction and wear of PTFE-polyimide composites under the atmosphere of nitrogen gas. The load range was 0.62-3.46 MPa, and the temperature range was room temperature and 200$^{\circ}$C. To mention some of the notable results, friction coefficient of PTFE 100% varied relatively little within the given load and temperature ranges. Polyimide 100% showed the lowest friction coefficient of 0.06 at 200$^{\circ}$C among all the experiments. PTFE 80%-polyimide 20% showed the lowest wear factors on the whole. Friction coefficient of PTFE 20%-polyimide 80% varied from the highest 0.35 to the lowest 0.09 among all the materials at room temperature, and showed almost the same lowest values with polyimide 100% at 200$^{\circ}$C. Suggestion of friction and wear mechanisms of the materials was tried to explain the observed phenomena including above mentioned results.

• Proceedings of the KSPS conference
• /
• 2004.05a
• /
• pp.133-137
• /
• 2004

This study investigates spectral characteristics of frication noise in Korean sibilants in terms of center of gravity and skewness. Specifically, the present study seeks to observe the two parameters with emphasis on place of articulation in different vowel environments. This study also examines whether these parameters can discriminate phonation types. The results showed that the fricatives are palatalized in front of the front vowel /i/ and the affricates are articulated at the same place of articulation regardless of the following vowels. This study also suggests that the place of articulation of the fricatives followed by /i/ is the same as those of the Korean affricates. With regard to the phonation type, there was a significant difference in the center of gravity between lax and tense series for both fricatives and affricates.

• MALSORI
• /
• no.49
• /
• pp.31-50
• /
• 2004

This study investigates spectral characteristics of frication noise in Korean sibilants in terms of center of gravity and skewness. Specifically, the present study seeks to observe the two parameters with emphasis on place of articulation in different vowel environments. This study also examines whether these parameters can discriminate phonation types. The results showed that the fricatives are palatalized in front of the front vowel /i/ and the affricates are articulated at the same place of articulation regardless of the following vowels. This study also suggests that the place of articulation of the fricatives followed by /i/ is the same as those of the Korean affricates. With regard to the phonation type, there was a significant difference in the center of gravity between lax and tense series for both fricatives and affricates.

• Phonetics and Speech Sciences
• /
• v.9 no.2
• /
• pp.31-38
• /
• 2017

This study aims to examine the acoustic characteristics of Korean sibilant, especially aspiration in Korean fricatives (plain: /s/, fortis: /s'/) and affricates (aspirated: /$ts^h$/, lenis: /ts/, and fortis: /ts'/). Duration values (closure duration, frication duration, aspiration duration), center of gravity (COG) (of the total duration, of the two portions, in 10 ms), H1-H2 values (at the vowel onset) were examined in order to investigate the phonetic feature of aspiration in frication noise. This study further discusses how to define criteria for identifying aspiration in sibilant sounds by adopting 3 visual criteria for assessing aspiration. This visually-designated aspiration onset points are further matched with the COG decline points in 10 ms windows. The result shows that all the non-fortis sounds (/s/, /$ts^h$/, /ts/) contain aspiration, causing similar values of COG and H1-H2.

• MALSORI
• /
• no.40
• /
• pp.1-12
• /
• 2000

This paper investigated how $/\int/$ in English and German is perceived and interpreted in the loanwords in Korean. $/\int/$ in these languages does not show one-to-one correspondence in Korean: $/\int/$ in the coda position in English and German is perceived as [swi] in Korean while $/\int/$ in the onset position is perceived as [syu]. This paper examined phonetic characteristics of $/\int/$ in English and German through its acoustic analysis and attempted to figure out which factor could explain this surface distribution of [swi] and [syu]; phonological (onset vs. coda) or phonetic (coarticulation) factor. Two acoustic features of $/\int/$ in English and German were examined: duration and energy Peak frequency of the frication noise. German $/\int/$ Perceived as [swi] in Korean showed higher energy Peak frequency and longer duration than that perceived as [syu] in Korean. English iii perceived as [swi] also showed longer duration than that Perceived as [syu] in Korean but energy Peak frequency showed different behavior. English $/\int/$ showed coarticulation with the preceding vowel rather than being affected by its position in the syllable in English. This paper concludes that 1)Phonetic characteristics used are duration and energy Peak frequency of its frication noise when $/\int/$ in English and German are adopted in Korean, 2)duration is used prior to energy peak frequency, which can be used as an enhancing feature.

• Phonetics and Speech Sciences
• /
• v.13 no.1
• /
• pp.37-44
• /
• 2021

While recent acoustic studies have reported associations of fronted sibilants (fricatives /s s⁎/ and affricates /tɕ tɕ⁎/) with gender in Seoul Korean, there have not been any studies examining the relationship of the variants with adult speakers' ages. The current study analyzes sibilant productions from 39 adult speakers born between 1942 and 2008 (19 females) in terms of spectral peak frequencies (SPFs) in frication, an acoustic index of place of articulation (POA). The results indicate some phonetic contexts where higher sibilant SPFs, i.e., fronter POAs, are associated with younger adults and those fronted variants are realized in a gender-differentiated manner -- tense affricates and word-initial tense fricatives before /i/ in the females' productions, and word-medial tense fricatives before /a/ in the males' productions. The findings confirm that the distributions of the fronted sibilants are accounted for not only by the speakers' gender but also by their ages, indicating that the fronted variants are innovative forms of realizing sibilants in Seoul Korean. In addition, the current results convincingly show that the fronted sibilant variants are not mere reflections of individuals' physiological differences since they are not observed across all of the examined phonetic contexts.

• Phonetics and Speech Sciences
• /
• v.5 no.2
• /
• pp.3-10
• /
• 2013

The purpose of this study is to analyze the acoustic characteristics of Korean alveolar sibilant sounds of children with cerebral palsy by acoustic analysis. Thirteen children with spastic cerebral palsy aging from 6 to 10 years old, were selected by an articulation test, and compared with a control group of thirty children. The meaningless monosyllable CV, disyllable VCV(/asa/) and frame sentence including target syllables CV were measured. C was from the /s, s'/, and V was from the set /a, i, u, ${\varepsilon}$, o, ɯ, ʌ/. Multi-Speech was used for data recording and analysis. As a result, the frication duration of lenis-glottalized alveolar sibilant of children with cerebral palsy was significantly shorter than that of the control group in CV, VCV and frame sentence. The vowel duration in the following lenis-glottalized alveolar sibilant of children with cerebral palsy was significantly longer than that of the control group in CV, VCV and frame sentence. The children with cerebral palsy showed frequency and intensity of friction intervals which were significantly lower than in the control group in CV, VCV and frame sentence. In the comparison of the lenis-glottalized alveolar sibilant by the children with cerebral palsy group's phonation types, the frication duration showed a significant difference between the phonation types in CV, VCV and between the phonetic contexts. The glottalized-sibilant was longer than the lenis-sibilant in all the phonetic contexts. The subsequent vowel duration showed a significant difference between the phonation types in VCV and between the phonetic contexts(p<.05). The vowel duration in the following glottalized-sibilant was longer than the vowel duration in the following lenis-sibilant in all the phonetic contexts. In the frequency there was a significant difference between the phonation types in CV, and in the intensity there was a significant difference between the phonation type in CV and VCV. The children with spastic cerebral palsy had difficulty in articulating the alveolar sibilant due to poor control ability in laryngeal, respiration and articulatory movements which require fine motor coordination. This study quantitatively analyzes the acoustic parameters of the alveolar sibilant in various phonetic contexts. Therefore, the results are expected to help provide fundamental data for an intervention of articulation treatment for children with cerebral palsy.