• Journal of Korea Multimedia Society
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• v.5 no.4
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• pp.393-398
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• 2002

The conventional bit allocation scheme for MPEG-1 audio encoding searches the subband with minimum MNR(mask-to-noise ratio) repetitively until its operation is completed, which occupies most of its total computational complexity. In this paper, as a computationally efficient approximation of it, we propose a new bit allocation scheme with a simple subband search and compare it with the existing schemes[1][2] in terms of the computational complexity and sound quality. For the performance comparison, we used the pop music signal contained in SQAM(sound quality assess material) CD from EBU. Simulation results show that the computational complexity of the proposed method is about 42% of that of the existing one in [1] and the sound quality difference in terms of MNR between the two schemes is within the 0.2 ㏈, for the case of using the layer II at the bit rate of 128 kbps.

• Journal of Digital Contents Society
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• v.8 no.3
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• pp.341-346
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• 2007

The purpose of this paper is to propose the design of VADSM(Value-Added Digital Speaker Module) which tunes up the speaker unit by measuring the speaker's frequency responses and controlling EQ band. This module can reduce audible distortions at particular frequency band and improve some flatness in the speaker's frequency response. VADSM is composed of DSP AMP and speaker unit. When a speaker transforms electrical signal to sound, the magnitude response at some frequencies are more or less than normal level. So, DSP AMP can be used to adjust those magnitudes up or down by controlling its EQ bands.

• The Magazine of the IEIE
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• v.29 no.1
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• pp.82-92
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• 2002

침체된 가전 산업과 IT 산업을 일으켜 세울 가장 유력한 기술이 홈 네트워크 기술임에는 많은 공감대를 형성하고 있는 것으로 보인다. 정보통신부가 홈 네트워킹 기술을 이용하여, 기존의 가전 시장이 겪고 있는 심각한 침체 현상을 해소하고 전 국민들의 정보화 마인드 확산을 위해 지난 2000년 3월, 인터넷 정보가전 산업 협의회를 구성하였으며, 5년 동안 약 1조 천억원의 연구비를 투입하여 홈 네트워크 및 사이버 아파트 구축을 위한 기술 개발 및 표준을 제정하고 있는 것이 이를 입증하고 있는 것이다. 이와 같은 홈 네트워킹 기술중에서 IEEE 1394 기술은 오디오 비디오 기기의 디지털화가 이루어지고 멀티미디어 환경이 부상함에 따라 이들간의 공통된 새로운 인터페이스 방식의 필요에 의해 발생한 버스 방식으로 USB가 제공하지 못하는 고속의 실시간 데이터 전송을 가능하게 해주는 차세대 핵심 기술이다. 기가비트급의 높은 데이터 전송율을 자랑하는 IEEE1394 기술은 따라서 멀티미디어 PC와 오디오/비디오 등 높은 대역폭을 요구하는 가전기기를 하나로 묶어줄 수 있는 유일한 기술이며, 그 위에 TCP/IP 프로토콜을 얹어서 인터넷과도 직접 연결될수 있다. 본 고에서는 홈 네트워킹의 기본 개념을 살펴보고, 홈 네트워킹의 중심으로 판단되는 Digital TV와 주변 가전 기기 사이에서 MPEG2-TS신호의 실시간 전송을 가능하게 하는 디지털 인터페이스 기술인 IEEE1394와 그 관련 기술의 동향에 대해 소개하였다. IEEE802.11a 기술을 이용한 무선 1394 기술은 댁내 전반에 산재해 있는 이러한 가전기기를 연결시켜줄 수 있는 Home Network Backbone이 될 것으로 전망된다.

• Journal of Broadcast Engineering
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• v.6 no.1
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• pp.21-31
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• 2001

In the PN-sequence based audio watermarking system, the PN sequence is shaped by a filter derived from the psychoacoustic model to increase robustness and inaudibility The psychoacoustic model calculated in each audio segment, however, requires heavy computational loads. In this paper, we propose an efficient watermarking system adopting a fixed-shape perceptual filter that substitutes psychoacoustic model derived filter. The proposed filter can shape the PN-sequence to be inaudible and enable to embed the robust watermark in a simple manner. Moreover, we propose an anchitecture for the PN-sequence compensation fitter In the watermark detecter to increase correlation between the watermark and the PN-sequence. With the proposed architecture, the blind watermark detection performance has been enhanced.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.2
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• pp.253-258
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• 2012

A computationally efficient interpolation filter with a low-distortion performance is a key component to utilize the naturally-sampled pulse width modulation (NPWM) in a digital domain. To realize the efficient interpolation filter, we propose a novel design based on the recently-proposed modified Farrow filter. The proposed filter shows a better pass-band distortion performance maintaining similar degree of complexity compared with the conventional Lagrange interpolation filter. We achieve the maximum distortion deviation of 10-3 dB to 20-kHz audible frequency range and distortion reduction of 1/6 times compared with the Lagrange interpolation filter.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.1
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• pp.81-87
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• 2013

In this paper, we propose a music search algorithm for automotive infotainment system. The proposed method extracts fingerprints using the high peaks based on log-spectrum of the music signal, and the extracted music fingerprints store in cloud server applying a hash value. In the cloud server, the most similar music is retrieved by comparing the user's query music with the fingerprints stored in hash table of cloud server. To evaluate the performance of the proposed music search algorithm, we measure an accuracy of the retrieved results according to various length of the query music and measure a retrieval time according to the number of stored music database in hash table.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.6
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• pp.1391-1396
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• 2010

Recently, communication components prefer Bluetooth or Zigbee for PAN. However, using these makes expensive and complicated products such as audio equipments, mobile phones, PC, etc. for transmitting simple messages with low rate. In this paper, we propose wireless communication method using ultrasonic in the audio frequency limit band with speakers and microphones which are in products. We suggest transmitting and receiving methods in the audio frequency limit band for transmitting data without affecting audio signal, and implement an ultrasonic communication modem. Finally, we verify the performance of the ultrasonic communication modem by experiments in an environment with background noise.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.1
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• pp.19-24
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• 2017

Nowadays, based on the advancement of IT techniques, innovative products combining IT techniques to PA system are developing. In this paper, we presented the hybrid mixer controller for digital PA system. We develop the integrated mixer controller which includes the digital mixer composing an existing digital PA system and function of digital integrated controller. Developed integrated mixer controller consists of multichannel mixer function with 16 audio input channels, 8 output channels. And, it has an equalizer for processing digital audio signal, matrix and limiter. Also, the developed controller has some features such as internet connection for controlling of overall PA system and remote monitoring of mixer process condition.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.109-112
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• 2010

Recently, communication components prefer Bluetooth or Zigbee for PAN. However, using these makes expensive and complicated products such as audio equipments, mobile phones, PC, etc. for transmitting simple messages with low rate. In this paper, we propose wireless communication method using ultrasonic in the audio frequency limit band with speakers and microphones which are in products. We suggest transmitting and receiving methods in the audio frequency limit band for transmitting data without affecting audio signal, and implement an ultrasonic communication modem. Finally, we verify the performance of the ultrasonic communication modem by experiments in an environment with background noise.

• Journal of Broadcast Engineering
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• v.9 no.1
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• pp.9-16
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• 2004

In this paper, we present a speech enhancement method as a pre-processor for voice commander under car environment. For the friendly and safe use of voice commander in a running car, non-stationary audio signals such as music and non-candidate speech should be reduced. Ow technique is a two microphone-based one. It consists of two parts Blind Source Separation (BSS) and Kalman filtering. Firstly, BSS is operated as a spatial filter to deal with non-stationary signals and then car noise is reduced by kalman filtering as a temporal filter. Algorithm Performance is tested for speech recognition. And the results show that our two microphone-based technique can be a good candidate to a voice commander.