• The Journal of the Acoustical Society of Korea
• /
• v.33 no.1
• /
• pp.75-80
• /
• 2014

The quality of real-time Voice over Internet Protocol (VoIP) network is affected by network impariments such as delays, jitters, and packet loss. This paper proposes a packet loss concealment algorithm based on voice classification for enhancing VoIP speech quality. In the proposed method, arriving packets are classified by an adaptive thresholding approach based on the analysis of multiple features of short signal segments. The excellent classification results are used in the packet loss concealment. Additionally, linear prediction-based packet loss concealment delivers high voice quality by alleviating the metallic artifacts due to concealing consecutive packet loss or recovering lost packet.

• Journal of Digital Contents Society
• /
• v.8 no.3
• /
• pp.341-346
• /
• 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 Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.3
• /
• pp.61-69
• /
• 2018

In this paper, we propose a method for recognizing ground target using dual polarization channels in millimeter waveband air-to-surface radar. First, the Push-Broom target detection method is described and the received signal is modeled considering flight-path scenario of air-to-surface radar. The scattering centers were extracted using the RELAX algorithm, which is a time domain spectral estimation technique, and the feature vector of the target was generated. Based on this, a DB for 4 targets is constructed. As a result of the proposed method, it is confirmed that the target classification rates is improved by more than 15% than the single channel using the data of the dual polarization channel.

• Annual Conference on Human and Language Technology
• /
• 1989.10a
• /
• pp.120-125
• /
• 1989

음성 신호에는 언어정보이외에 여러 요인에 의한 정보가 포함되어 있어서, 문자와 일대일로 대응되는 분절을 정확하게 검출하기가 어렵다. 본 연구에서는 선형 예측계수 (LPC) 스펙트럼의 첨두 부분을 강조한 이진 (binary) 스펙트럼을 제안하고, 이를 바탕으로 음의 안정영역과 천이영역을 통합하여 음향특징을 추출하고자 한다. 각 영역의 특징은 이진 스펙트럼을 누적하여 구하며, 통합적인 특징은 각 영역의 특징을 결합한 관계적 특징으로 나타낸다. 제 2 차 포르만트 주파수의 궤적을 관계적 특징으로 하여, 양순 비음과 치조 비음을 구별한 결과, 모음의 문맥과 화자에 비교적 독립적인 인식결과를 얻을 수 있었다. 또한 이진 스펙트럼이 원래의 스펙트럼에 포함된 정보를 유지하는지 검토하기 위해, 같은 거리척도 (distance measure) 에 의해 인식 실험한 결과 이진 스펙트럼의 성능이 오히려 우수하게 나타났으며, 관계적 이진 스펙트럼의 경우 화자에 따른 변화가 더욱 적었다. 음성에 백색 잡음 (Gaussian white noise)을 더하여 잡음음성 (noisy speech) 을 만든 뒤, 같은 방법으로 실험한 결과도 유사한 인식결과를 얻을 수 있어 제안된 이진 스펙트럼의 유효성을 확인하였다.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.25 no.3
• /
• pp.272-278
• /
• 2015

This paper studied various parameter extraction methods using pitch information of speech for the development of the emotion recognition system. For this purpose, pitch parameters were extracted from korean speech database containing various emotions using stochastical information and numerical analysis techniques. GMM based emotion recognition system were used to compare the performance of pitch parameters. Sequential feature selection method were used to select the parameters showing the best emotion recognition performance. Experimental results of recognizing four emotions showed 63.5% recognition rate using the combination of 15 parameters out of 56 pitch parameters. Experimental results of detecting the presence of emotion showed 80.3% recognition rate using the combination of 14 parameters.

• Progress in Medical Physics
• /
• v.5 no.2
• /
• pp.27-34
• /
• 1994

In this study, we developed E.C.G telemetry system by using a digital communication method. This system is composed of a number of Ambulatory Telemetry System(ATS)'s that use for the same frequency and one center monitoring system(CMS) utilized the personal computer. The purpose of the ATS is, Therefore, to present for acqusition ECG data and transmitting to CMS. The ATS hardware is based on one chip microprocessor (8096) included A/D convert, ECG pre amplifier, ID-decoder, TRX Gateway and FM TRX module. Using the PC can be convinet to processing and deposite for long terms continued patient data.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.14 no.1
• /
• pp.230-240
• /
• 1990

An exprimental research has been carried out to find the intermittent flow pattern in the transition region of a turbulent round jet in order to elucidate detailed turbulence structure and to accumulate basic data necessary for computational turbulence modelling. Turbulent signals were processed digitally to obtain conventional or conditional velocity components. The high-order conditional correlations obtained in this study showed similar trends as those of other free shear flows. It was found that the non-turbulent fluid contributes negligibly to the turbulent kinetic energy production and its diffusive transport and that the diffusion by bulk convection has the same order of magnitude as the gradient diffusion in the free boundary region. The statistical analyses such as flatness factor, skewness factor and probability density functions of turbulent and non-turbulent zone durations have also been performed.

• Journal of Korea Society of Industrial Information Systems
• /
• v.9 no.2
• /
• pp.81-88
• /
• 2004

For scale and rotation invariant pattern recognition of images with noise, an optical wavelet CHF-fSDF filter is proposed. Wavelet CHF-fSDF filter is synthesized by each single CHF extracted from scale-changed and wavelet transformed images for a referene image as training images. The proposed optical wavelet CHF-fSDF filter is the type of the matched filter so that it can use the structure of 4f optical correlation system. The results of computer simulation show that the proposed filter has the rotation and scale-invariant correlation output and it is useful in the noisy input.

• 한국HCI학회:학술대회논문집
• /
• 2009.02a
• /
• pp.756-762
• /
• 2009

The interest of show industry as leisure and culture bring about quantitative increase of public facility. It indicate the effort of bring culture benefits to the disable and the general who want detail information. Especially, there is less technology and service to help them. So it is very necessary method which is using the audial and visual transfer technology to solve the limitation. This study aimed at indicating the method that applied the audial and visual transfer technology which are useful for both The disable and General Audience.

• Journal of the Korean Society of Safety
• /
• v.16 no.1
• /
• pp.88-93
• /
• 2001

This study discusses frequency analysis based on autoregressive (AR) time series model, and process characterization in orthogonal cutting of a fiber-matrix composite materials. A sparsely distributed idealized composite material, namely a glass reinforced polyester (GFRP) was used as workpiece. Analysis method employs a force sensor and the signals from the sensor are processed using AR time series model. The resulting pattern vectors of AR coefficients are then passed to the feature extraction block. Inside the feature extraction block, only those features that are most sensitive to different types of cutting mechanisms are selected. The experimental correlations between the different chip formation mechanisms and AR model coefficients are established.