• The Journal of the Acoustical Society of Korea
• /
• v.40 no.5
• /
• pp.503-514
• /
• 2021

Reverberation in speech signals tends to significantly degrade the performance of the Blind Source Separation (BSS) system. Especially in online systems, the performance degradation becomes severe. Methods based on joint diagonalizability constraints have been recently developed to tackle the problem. To improve the quality of separated speech, in this paper, we add the proposed de-reverberation method to the online BSS algorithm based on the constraints in reverberant environments. Through experiments on the WSJCAM0 corpus, the proposed method was compared with the existing online BSS algorithm. The performance evaluation by the Signal-to-Distortion Ratio and the Perceptual Evaluation of Speech Quality demonstrated that SDR improved from 1.23 dB to 3.76 dB and PESQ improved from 1.15 to 2.12 on average.

• The Journal of the Acoustical Society of Korea
• /
• v.38 no.4
• /
• pp.406-413
• /
• 2019

This paper proposes a speech enhancement method through the process of combining the gain function with spectrum subtraction method in the two microphone array with close spacing. A speech enhancement method that uses a gain function estimated by the SNR (Signal-to Noise Ratio) based on the multi frequency band coherence function causes the performance degradation in high correlation between input noises of two channels. A new speech enhancement method is proposed where the weighted gain function is used by combining the gain function from the spectral subtraction. The performance evaluation of the proposed method was shown by comparison with PESQ (Perceptual Evaluation of Speech Quality) value which is an objective quality evaluation test provided by the ITU-T (International Telecommunications Union Telecommunication). In the PESQ tests, the maximum 0.217 of PESQ value is improved in the various background noise environments.

• The Journal of the Acoustical Society of Korea
• /
• v.27 no.5
• /
• pp.256-261
• /
• 2008

In this paper, we propose a novel approach to improve the performance of minima controlled recursive averaging (MCRA) which is based on the conditional maximum a posteriori criterion. A crucial component of a practical speech enhancement system is the estimation of the noise power spectrum. One state-of-the-art approach is the minima controlled recursive averaging (MCRA) technique. The noise estimate in the MCRA technique is obtained by averaging past spectral power values based on a smoothing parameter that is adjusted by the signal presence probability in frequency subbands. We improve the MCRA using the speech presence probability which is the a posteriori probability conditioned on both the current observation the speech presence or absence of the previous frame. With the performance criteria of the ITU-T P.862 perceptual evaluation of speech quality (PESQ) and subjective evaluation of speech quality, we show that the proposed algorithm yields better results compared to the conventional MCRA-based scheme.

• Journal of Korean Society for Quality Management
• /
• v.33 no.4
• /
• pp.55-74
• /
• 2005

This study tries to examine the competitive strategy of service quality in Korean financial market. the purpose of this study is to find out the strategic implication of Korean commercial banks throughout the service level of experienced customers and the services positioning map. Especially, taking the advantage of a customer's service perception and request attributes make the service positioning map The findings from this research are as follows; the characteristic of each customer is derived from income and investment. and the service positioning map is derived from the characteristic of each customer.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.6
• /
• pp.1120-1125
• /
• 2010

In the speech system, for example hearing aid as well as speech communication, speech quality is degraded by environmental noise. In this study, to enhance the speech quality which is degraded by environmental speech, we proposed an algorithm to reduce the noise and reinforce the speech. The minima controlled recursive averaging (MCRA) algorithm is used to estimate the noise spectrum and spectral weighting factor is used to reduce the noise. And partial masking effect which is one of the human hearing properties is introduced to reinforce the speech. Then we compared the waveform, spectrogram, Perceptual Evaluation of Speech Quality (PESQ) and segmental Signal to Noise Ratio (segSNR) between original speech, noisy speech, noise reduced speech and enhanced speech by proposed method. As a result, enhanced speech by proposed method is reinforced in high frequency which is degraded by noise, and PESQ, segSNR is enhanced. It means that the speech quality is enhanced.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.9
• /
• pp.1410-1419
• /
• 1989

In this paper, we present a new synthetic high coding method which gives high image compression ratio. Given an image, only its low-pass component is transmitted by DCT coding` the high-pass component is not transmitted but synthesized using edge sharpening on the reconstructed low-pass image at the receiver. For the DCT coding which is used to encode the low-pass image, we used an improved version of Cox's variance estimator. Also, introduced are new image quality measures called GSNR and EPR which emphasize perceptual aspects of image quality. Experimental results show that the performance of the proposed synthetic high coding is better in various quality measures than that of Cox's adaptive transform coding. Also, it yields acceptable image quality with neither apparent block effect nor visible granular noise even at high compression ratio of about 30:1.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.28 no.2
• /
• pp.106-111
• /
• 2017

Background and Objectives : The purpose of this study was to investigate the criterion-related concurrent validity of two standardized auditory-perceptual assessments and the Acoustic Voice Quality Index (AVQI) for measuring dysphonia severity in patients with vocal cord paralysis (VCP). Materials and Methods : Total 210 patients with VCP and 236 normal voice subjects were asked to sustain the vowel [a:] and to read aloud the Korean text "Walk". A 2 second mid-vowel portion of the sustained vowel and two sentences (with 26 syllables) were recorded. And then voice samples were edited, concatenated, and analyzed according to Praat script. Two standardized auditory-perceptual assessment (GRBAS and CAPE-V) were performed by three raters. Results : The VCP group showed higher AVQI, Grade (G) and Overall Severity (OS) values than normal voice group. And the correlation among AVQI, G, and OS ranged from 0.904 to 0.926. In ROC curve analysis, cutoff values of AVQI, G, and OS were <3.79, <0.00, and <30.00, respectively, and the AUC of each analysis was over .89. Conclusion : AVQI and auditory evaluation can improve the early screening ability of VCP voice and help to establish effective diagnosis and treatment plan for VCP-related dysphonia.

• Journal of Fashion Business
• /
• v.27 no.2
• /
• pp.70-87
• /
• 2023

Today, VR, AR, and MR technologies that travel between real world and virtual world are rapidly developing. These technologies are adopted in luxury fashion brands for virtual fashion shows and runways, virtual retail shops and virtual fitting services. Despite its growth potential and social importance, virtual fashion space has been studies insufficiently. Therefore, this study aimed to examine the consumer experience on the virtual fashion space types, components of virtual fashion space, perceived value, and continuous usage intention. Prada, one of the most active luxury fashion brands in the VR field, was selected as the stimulus for an in-depth interview. Participants experienced virtual fashion show space through VR device (Oculus Quest 2 from Meta) before responding to the questions about their experience. Results showed that material space was more like virtual whereas perceptual space felt like reality. Participants could imagine about more virtual image from material space and more real image from perceptual space elements. Moreover, perceptual space enhanced the immersion, presence, and interactivity compared to material space. Most participants perceived that the virtual fashion show was useful and playful, leading to the continuous usage intention. It implies that improvements for some technical limitation from VR device and virtual contents can provide quality consumer experience in the future. Based on results of this study, fashion companies can establish useful marketing strategies for consumers' immersive and playful experiences when introducing virtual fashion space.

• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.911-914
• /
• 1998

In this paper, the importance of including small image features at the initial levels of a progressive second generation video coding scheme is presented. It is shown that a number of meaningful small features called details shouuld be coded in order to match their perceptual significance to the human visual system. We propose a method for extracting, perceptually selecting and coding of visual details in a video sequence using morphological laplacian operator and modified post-it transform is very efficient for improving quality of the reconstructed images.

• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.895-898
• /
• 1998

In this paper, we propose an efficient marker extraction algorithm for initial image segmentation in a bottom-up segmentation scheme. The proposed algorithm generates dense markers in visually complex areas and coarse markers in visually uniform areas. which conforms to the human perceptual system. Experimental results show that the proposed method achieves better subjective quality for fine initial image segmentation.