• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.12
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• pp.1589-1598
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• 1999

Conventional MSE or PSNR based methods for objective picture quality assessment of moving picture coder are not well correlated with subjective human evaluation. In recent years, the design of better objective quality assessment has attracted much intention and several picture quality metrics based on the properties of Human Visual System has been proposed. This paper proposes new metric which is appropriate for objective picture quality assessment of block based moving picture coder by considering frequency sensitivity, inter-intra channel masking and several distortion artifacts caused by block based coding. The experimental results show that the proposed method is good correlated with subjective assessment.

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

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1498-1499
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• 1998

Thin film inductors of 10 mm ${\times}$ 10 mm with spiral pattern of 14 turns were fabricated by sputtering, photo-masking, and etching processes. Their impedence characteristics and annealing after effects were investigated. After magnetic annealing, the impedence characteristics of the inductors were improved at comparatively low frequencies, but the tendencies of it for thr frequency changes were almost same. These improvement was caused by the annihilation of the internal stresses of films, Uniaxial field annealed thin film inductor had an inductance of 1000 nH, resistance of 6 $\Omega$, and quality factor of 1 at 2 MHz.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1260-1263
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• 2002

This paper takes the region segmentation in image processing and the semantic importance in an image analysis into consideration for digital image watermarking. A semantic importance for an object region, which is segmented by specific features, is determined according to the contents of the region. In this paper, face images are the targets of watermarking for their increasing importance, the use of frequency and strong necessity of protection. A face region is detected and segmented as an object region and encoded watermark information is embedded into the region. Employing a masking and filtering method, experiments are carried out and the results show the usefulness of the proposed method even when there are high compression and a synthesis as a case of copyright infringement.

• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.714-721
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• 2011

MPEG audio uses the masking effect, high frequency component synthesis based on spectral band replication, and channel expansion based on parametric stereo for efficient compression of audio signals. In this paper, we present an overview of the state-of-the-art channel expansion technology in MPEG audio. We also present technical overviews and application examples to broadcasting services for HE-AAC v.2, MPEG Surround, spatial audio object coding (SAOC), and unified speech and audio coding (USAC) which are MPEG audio codecs based on the channel expansion technology.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.5
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• pp.503-508
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• 2008

In this paper, various methods to improve the planetary gear noise in vehicles were introduced. Those cases of improvement have been used as good guidelines and references to prevent planetary noise problems. In this research, different types of planetary gear systems were also analyzed. The consequences of those analysis said in common that the planetary gear set generating noise mainly is the one which takes power directly from the turbine. Furthermore, a frequency versus vibration level map was introduced to judge how to solve the noise problem quickly in a vehicle development process. Besides, it is provided a predicting method which planetary gear set most contributes to noise problem taking in the vehicle and how to design the planetary gear set robustly.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.5
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• pp.424-431
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• 2002

This paper proposes a new quantitative image assessment model which is essential to verify the performance of block-based DCT coding. The proposed model considers not only global distortions such as frequency sensitivity and channel masking using HVS based visual model, but also distortions including several local distortions caused by block-based coding.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.7A
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• pp.1037-1043
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• 2000

In this paper we present an object-based watermarking scheme, which cuts out several featured portions from an image and casts chaotic sequences as a watermark into the extracted object image in the discrete wavelet domain with respect to the models of the human visual system. In such a way we can insert watermark to several objects of an image separately. Advantages of the proposed scheme include that it can protect featured object out of an image selectively as well as entire image and casts watermark sequences according to human visual masking utilizing the time-frequency localization property of the wavelet transform.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.1
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• pp.39-45
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• 2004

This paper proposes a new blind measurement model of blocking artifacts. This model plays an important role in the assessment and enhancement of image quality caused by block-based DCT coding system. The proposed model can measure blocking artifacts without reference to original images and consider the HVS based visual model such as frequency sensitivity and channel masking effect to detect and measure overall blocking artifacts quantitatively. The experimental results show that the proposed model is highly effective in measuring blocking artifacts.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.5
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• pp.333-338
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• 1999

Thin film inductors of $10 mm \times 10 mm$ with inner coil type of 14 turns were fabricated by sputtering, photo-masking, and etching processes. Their characteristics of impedances and annealing after were investigated. The properties of impedances of the thin film magnetic core inductors with inner coil type were improved by magnetic field annealing due to the removal of residual stress and the improvement magnetic properties of magnetic films. But the characteristics of frequency of the thin film magnetic core inductors were not improved by magnetic field annealing due to properties of the spiral pattern and inner coil type. The thin film magnetic core inductor annealed by uniaxal field annealing method showed an inductance of 1000 nH and resistance of$ 6 \Omega$ of 1 at 2 MHz.