• Phonetics and Speech Sciences
• /
• v.11 no.1
• /
• pp.19-27
• /
• 2019

Lateral approximants are well known as having complex articulatory characteristics, which vary cross-linguistically, across speakers, and across utterances. However, less attention has been paid to the articulation of Korean laterals, which do not contrast with a rhotic and may thus exhibit greater-than-normal variability. The focus of this study is to investigate the general articulatory characteristics of the Korean lateral [l] as well as the articulatory variation using novel 3D ultrasound imaging methods. The results of this study revealed significant between-speaker variation and some vowel-dependent variation with regard to the articulation of the Korean lateral [l], which has not been reported previously. Even though all participants in this study showed an anterior occlusion, the place of articulation and the size of the occlusion varied greatly across speakers. The data also revealed that left-right asymmetry is present in the articulation of the Korean lateral. The individual variation of the Korean lateral [l] suggests that it has a large articulatory-acoustic space for variation, since it has no contrasting sound that causes perceptual confusion.

• Phonetics and Speech Sciences
• /
• v.4 no.3
• /
• pp.31-41
• /
• 2012

Recent studies have shown that the stop system of Korean is undergoing a sound change in terms of the two acoustic parameters, voice onset time (VOT) and fundamental frequency (f0). Because of a VOT merger of a consonantal opposition and onset-f0 interaction, the relative importance of the two parameters has been changing in Korean where f0 is a primary cue and VOT is a secondary cue in distinguishing lax from aspirated stops in speech production as well as perception. In English, however, VOT is a primary cue and f0 is a secondary cue in contrasting voiced and voiceless stops. This study examines how Korean English learners use the two acoustic parameters of L1 in producing L2 English stops and whether the sound change of acoustic parameters in L1 affects L2 speech production. The data were collected from six adult Korean English learners. Results show that Korean English learners use not only VOT but also f0 to contrast L2 voiced and voiceless stops. However, unlike VOT variations among speakers, the magnitude effect of onset consonants on f0 in L2 English was steady and robust, indicating that f0 also plays an important role in contrasting the [voice] contrast in L2 English. The results suggest that the important role of f0 in contrasting lax and aspirated stops in L1 Korean is transferred to the contrast of voiced and voiceless stops in L2 English. The results imply that, for Korean English learners, f0 rather than VOT will play an important perceptual cue in contrasting voiced and voiceless stops in L2 English.

• Phonetics and Speech Sciences
• /
• v.6 no.4
• /
• pp.27-36
• /
• 2014

This study provided longitudinal examination of the Chinese learners' acquisition of Korean vowels. Specifically, I examined the Chinese learners' Korean monophthongs /i, e, ɨ, ${\Lambda}$, a, u, o/ that were created at the time of 1 month and 12 months, tried to verify empirically how they learn by dealing with their mother tongue, and Korean vowels through dealing with pattern of the Perceptual Assimilation Model (henceforth PAM) of Best (Best, 1993; 1994; Best & Tyler, 2007) and the Speech Learning Model (henceforth SLM) of Flege (Flege, 1987; Bohn & Flege, 1992, Flege, 1995). As a result, most of the present results are shown to be similarly explained by the PAM and SLM, and the only discrepancy between these two models is found in the 'similar' category of sounds between the learners' native language and the target language. Specifically, the acquisition pattern of /u/ and /o/ in Korean is well accounted for the PAM, but not in the SLM. The SLM did not explain why the Chinese learners had difficulty in acquiring the Korean vowel /u/, because according to the SLM, the vowel /u/ in Chinese (the native language) is matched either to the vowel /u/ or /o/ in Korean (the target language). Namely, there is only a one-to-one matching relationship between the native language and the target language. In contrast, the Chinese learners' difficulty for the Korean vowel /u/ is well accounted for in the PAM in that the Chinese vowel /u/ is matched to the vowel pair /o, u/ in Korean, not the single vowel, /o/ or /u/.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.7
• /
• pp.2938-2956
• /
• 2020

Objective image quality assessment (IQA) models have been developed by effective features to imitate the characteristics of human visual system (HVS). Actually, HVS is extremely sensitive to color degradation and complex texture changes. In this paper, we firstly reveal that many existing full reference image quality assessment (FR-IQA) methods can hardly measure the image quality with contrast and masking texture changes. To solve this problem, considering texture masking effect, we proposed a novel FR-IQA method, called Texture and Color Quality Index (TCQI). The proposed method considers both in the masking effect texture and color visual perceptual threshold, which adopts three kinds of features to reflect masking texture, color difference and structural information. Furthermore, random forest (RF) is used to address the drawbacks of existing pooling technologies. Compared with other traditional learning-based tools (support vector regression and neural network), RF can achieve the better prediction performance. Experiments conducted on five large-scale databases demonstrate that our approach is highly consistent with subjective perception, outperforms twelve the state-of-the-art IQA models in terms of prediction accuracy and keeps a moderate computational complexity. The cross database validation also validates our approach achieves the ability to maintain high robustness.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.45 no.1
• /
• pp.29-37
• /
• 2008

With the rapid development of display technology as well as the diversity of display, image quality assessment plays an important role in display color reproduction. The image quality has described by objective evaluation based on the physical measured data, such as contrast ratio, color reproduction range, color temperature, and gamma characteristics, etc., however, the final judgement is achieved by perceptual quality assessment of observers. Therefore, it is necessary to investigate the relationship between physical performance of display and perceptual image quality. Thus, in order to evaluate objectively the color reproduction characteristics of two mobile displays, TFT-LCD and AMOLED, we measured the darkroom contrast ratio of full screen, luminance and color temperature of full-screen white, full-screen gray and color linearity, tone reproduction of color scales for each RGB primary, and color reproduction range. Then the pair-wise comparison is implemented for image experts and naive observers not only to judge their preference on principal evaluation attributes but also to subjectively describe perceived image quality. Through two evaluation processes, we derived the objective bases that can prove the results of subjective image quality assessment by interconnecting physical factors that have influence on observers' preference judgements. Finally, this paper provided important information for improving the image quality and increasing preference from an observer's point of view.

• Science of Emotion and Sensibility
• /
• v.20 no.2
• /
• pp.137-148
• /
• 2017

The present study examined the effect of stimulus contrast and color on detection of a target embedded in streams of letters. In Experiment 1, each trial displayed four rapid serial visual presentation (RSVP) streams of letters (i.e., multi-RSVP), and each stream occupied one of four different locations. Each frame in the RSVP stream had four white distractors at the locations except one frame where a dim grey target was displayed at a location with three white distractors at the remaining locations. In the low-visibility target condition, the target's grey color was slightly darker than the background grey whereas much dimmer in the high-visibility condition. Participants were asked to report presence of a predesignated target as quickly and accurately as possible upon its detection in each trial, and their target detection turned out more accurate and quicker in the high-visibility than the low-visibility condition. In Experiment 2, the same RSVP displays and task as Experiment were used, but the grey target letters in the high-visibility condition were replaced with those of distinct chromatic colors. Participants detected target presence more accurately in the high-visibility condition, but the reaction time did not differ between the visibility conditions. The results indicate that higher stimulus contrast as well as distinct color can improve perception of a target stimulus displayed among visually-demanding background, but also suggest that stimulus contrast may play a more substantial role for such perceptual improvement.

• Phonetics and Speech Sciences
• /
• v.9 no.3
• /
• pp.33-40
• /
• 2017

This study aimed to examine how Korean-English bilinguals make use of VOT and F0 cues in perception and production of Korean (lenis vs. aspirated) and English (voiced vs. voiceless) stops. It was explored whether bilinguals with extensive experience living in the U.S. exhibit native-like or interactive patterns in the cue use for both languages. Participants produced monosyllabic word-initial stops within a carrier sentence in each language, and performed forced-choice identification tasks with synthesized stimuli varying in 7 VOT steps and 7 F0 steps with base tokens of /$t^han$/ for Korean and /$t{\ae}n$/ for English. Listeners were required to select either /tan/ or /$t^han$/ for Korean and either /$d{\ae}n$/ or /$t{\ae}n$/ for English. The results from binary logistic regression analyses for each listener indicated that all bilinguals placed greater weight on F0 than VOT when distinguishing between the Korean lenis and aspirated stops, and greater weight on VOT than F0 in distinguishing between the English voiced and voiceless stops. In terms of production, all participants showed remarkably overlapping ranges in the VOT dimension and separating ranges in the F0 dimension for the stop contrast of Korean, while forming overlapping ranges in the F0 dimension and separating ranges in the VOT dimension for the stop contrast of English. These results indicate that the bilinguals with extensive exposure to L2 manage the stop systems of the two languages independently, both in perception and production, employing the opposite cue use for stops in the two languages. It was also found that the absolute beta-coefficient values of the perceptual cues for Korean stops were generally smaller than those for English and those reported in a previous study as for later bilinguals, which may have resulted from Korean not being their dominant language.

• Science of Emotion and Sensibility
• /
• v.13 no.1
• /
• pp.251-258
• /
• 2010

'Naturalness' is the important "ness" which is a key factor in image quality assessment. 'Naturalness' is a representive factor depending on the context of the image which arouses different emotions. The Image Quality Circle was split into two steps. The first step is predicting the visual perceptual attribute which are lightness, colourfulness, hue and contrast. The next step is SSE which is dependent to image contents. In this study the image contents are grouped in genres. The images were rendered using four different colour attributes which are lightness, contrast, colourfulness and hue. Using a scale, the score of image quality and SSE was asked to each participant for all rendered images. A seven-point category scale of increasing amount of "ness" is used as a quantitative adjectives sequence. The image quality model was built by combining the SSEs for each scene. The SSEs, where vividness is common, are considered as independent variables to predict the image quality score. Then the vividness model was built using colour attributes as variables to predict the vividness of each scene (genre). Vividness is an important factor of naturalness which the meaning is different for all scenes that links the naturalness and image quality. The vividness meaning was different for each scene (genre). Therefore, the colour attributes that express the vividness would depend on the image content.

• Journal of the Korean Society of Costume
• /
• v.55 no.4 s.94
• /
• pp.79-94
• /
• 2005

The goal of this research, contorted from the perspective of media aesthetics, is to uncover the ways how mechanical/cybersensual fashion products express aesthetic characteristics of cybernetics, by comparing them with digital products designed by an application of cybernetics. The other goal is to provide a cultural and design framework of cybernetics as d digital-environmental medium for fashion in which hightech and human sensibilities are fused. The results urged to explore two new contrasting perceptual possibilities for an understanding of digital technology application: negative and positive feedbacks. Cybernetic optimism, centered on technological dimensions, focuses on a concept of fashion that emphasize instrumental aspects-efficiency and convenience. In contrast, cybernetic pessimism focuses on digital fashion that expresses environmental destruction and the loss of human identity. A comparative analysis of the aesthetics of expression in digital fashion design and digital industrial products from a cybernetic perspective showed that in digital environment society, the combination of negative and positive feedbacks resulted in design products in which internal and external aspects of beauty complemented each other.

• Speech Sciences
• /
• v.10 no.2
• /
• pp.287-301
• /
• 2003

The purpose of this study was to examine whether the same vowel sounds are perceived differently by the two local dialect speakers, Seoul dialect speakers (SDS) and Kyungnam dialect speakers (KDS), whose vowel systems differ each other. In the first experiment SDS and KDS heard vowels synthesized in vowel space with F1 by F2 and categorized them into one of 10 Korean monophthongs. The results showed that SDS and KDS perceived the synthesized vowels differently. For example, /$\varepsilon$ versus /e/ contrast, ${\o}$/, and /y/ are differentiated by SDS, whereas they are perceptually confused by KDS. We also observed that /i/ could not be perceived unless the vowel synthesis included F3 or higher formants. In the second experiment SDS and KDS performed the similarity rating task of 10 synthesized Korean monophthongs. Two-dimensional MDS solution based on the similarity rating scores was obtained for each dialect group. The first dimension can be named 'vowel advancement' and the second 'vowel height'. The comparison of the two MDS solutions showed that the overall psychological distances among the vowels are shorter in KDS than SDS and that especially the distance between /$\Lambda$/ and /i/ is shorter in KDS than SDS. The result suggested that perception or mental representation of vowels depends on the vowel system of the listener's dialect or language. Further research problems were discussed in the final section.