• Proceedings of the Acoustical Society of Korea Conference
• /
• 1998.06c
• /
• pp.143-146
• /
• 1998

자연스러운 한국어의 음성합성을 위해서는 음운의 지속시간의 제어가 매우 중요하다. 본 연구에서는 POW3848 어절에 대한 음성 데이터에 대해 음운 세그먼트, 음운 라벨링, 품사 태깅을 행한 음성 데이터베이스를 구축하여 한국어 음운의 지속시간을 변화시키는 시간 특징을 통계적으로 분석하였다. 이 시간 특징들 중 변화 폭이 큰 요인들을 제어요소로 각 음운의 고유길이를 최대한 배제하고 단지 음운 발성 환경의 영향에 의한 지속시간 변화만을 고려하는 정규화 지속시간에 대한 회귀트리로 한국어 음운 지속시간을 모델화 하였다. 제안된 음운 지속시간 모델을 실시간 제어 알고리즘으로 구현하여 평가한 결과, 음운 지속시간 예측오차의 88% 정도가 25ms이내 이었고 예측치와 관측치 간의 다중 상관관계수는 0.92 정도로 평가되어, 제안된 모델의 타당성이 입증되었다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2019.11a
• /
• pp.71-72
• /
• 2019

최근 공공안전 분야에서는 국민의 위험상황을 분석하여 선제적으로 예측을 하여 국민의 안전을 보장하기 위한 요구사항이 대두대고 있다. 또한 스마트폰 및 스마트워치와 같은 고성능 모바일 단말 기기들의 대중화로 인해 해당 기기들에 부착된 다양한 센서 데이터들을 융복합하여 분석할 경우, 수집한 센서 데이터의 잠재적 가치를 안전보장 측면에서 사용할 수 있는 장점이 있다. 본 논문에서는 대인, 대물, 장소에 해당하는 로그 데이터들을 융복합 분석하여 보호대상자의 안전을 지원하는 다중로그 플랫폼 기반 이동경로 분석 기법을 제안한다. 다중로그 플랫폼에서 수집하는 보호대상자의 이동 경로 궤적을 활용하여 과거에 축적된 이동경로 패턴과 비교를 통해 현재 경로가 평소에 이용하던 경로와의 유사도를 추천하게 된다. 해당 이동 경로 분석 시스템은 위치기반 멀티모달 센서 데이터를 융복합 하여 보호대상자의 안전을 보장하는데 기여 할 것으로 예상된다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.10B
• /
• pp.1382-1389
• /
• 2001

움직임 보상-이산 코사인 변환 (motion compensation-discrete cosine transform : MC-DCT) 기반의 동영상 부호화 기법이 부호화 효율성 및 구현의 단순성으로 인해 널리 사용되고 있으나, 에러 환경에서 구조적으로 취약한 면이 있다. 본 논문에서는 다중 메모리 움직임 보상 예측 (long-term memory motion compensated prediction : LTMP) 기반의 다중 레프런스 프레임을 사용하여 에러에 강인한 동영상 부호화 기법을 제안한다. 또한 제안하는 알고리듬에 기반한 에러 은닉 기법 (error concealment : EC)을 구현한다. 즉, R-D (rate-distortion) 최적화에 프레임간 움직임 벡터 (temporal motion vectors)의 확산 인자를 추가하여 에러에 대한 강인성 및 에러 은닉 기법의 효율성을 증가시켰다. 또한, 제안하는 알고리듬은 시간축상의 에러 전파를 피드백 정보 (negative acknowledgement : NAK)를 사용하여 억제한다. 즉, NAK는 채널 에러에 의해 손실된 영역과 에러가 전파된 영역을 추정하여 움직임 보상 영역에서 제외되도록 하는데 이용된다. 따라서, 제안하는 알고리듬은 PSNR 측면에서 FIU (forced intra update)에 근사하는 성능을 보이나, FIU와는 달리 비트율의 증가를 피할 수 있어 제한된 대역폭의 네트웍을 효율적으로 사용할 수 있다. 컴퓨터 모의 실험을 통해 제안하는 알고리듬이 기존의 H.263 및 LTMP 기반의 부호기에 비해 에러 환경에서 주관적 및 객관적 화질 측면에서 성능이 우수함을 보인다.

• The Journal of the Acoustical Society of Korea
• /
• v.20 no.3
• /
• pp.34-41
• /
• 2001

In an IMBE (Improved Multi-band Excitation) speech coder, initial pitch estimation occupies most of the total computing time for the coder due to complex cost function and exhaustive search over candidate pitches. Future frames in initial pitch estimation cause inevitable time delay. Therefore, it is difficult to implement a real-time coder. Furthermore, unvoiced frames use the unnecessary pitch estimation as in the voiced frames. In this paper, each frame is determined voiced or unvoiced by Dyadic Wavelet Transform (DyWT) and, then, initial pitch estimation is performed only for voiced frame. Therefore different pitch estimation algorithms are employed between voiced and unvoiced frames incurring reduced time delay at transmitter and receiver. Simulation result show that the relative complexity of initial pitch estimation is reduced by 23％, and the processing time decreases down to 1/10 ∼ 1/1l of the IMBE coder while speech quality is almost maintained.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.7
• /
• pp.693-701
• /
• 2002

In this paper, we analyze the coverage of asynchronous IMT(International Mobile Telecommunication)-2000 reverse link with a MUD(Multi-User Detector) system. The MUD system is utilized to increase the coverage of reverse link. Also we have considered a propagation loss model and an interference effect. Because it is very difficult that we have calculated the interference accurately, so a fractional cell loading factor(F) is used in this paper. We make use of a MUD efficiency($\beta$) to analyze the performance; this efficiency is presented the MAI of reduction. A simulation utilizes Hata's model, we calculated the coverage according to voice and data services. In this paper, we have assumed that the frequency of carrier has 800 MHz or 1.9 GHz, and a bandwidth is decided 3.84 MHz. We have predicted the performance of actual system by the analysis of capacity and coverage.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.37 no.12
• /
• pp.1061-1068
• /
• 2013

This study predicts distillate productions according to design variables by numerical analysis when the waste heat from a diesel generator is added to the solar-assisted still proposed in a previous study. Mathematical models were set up in reference to previous studies, and the amount of heat exchange from the waste heat recovery pipe was considered. To ensure the reliability of numerical analysis, the result was compared with that of a previous study and then, the distillate productions according to design variables were obtained by the analysis model. The results were found to generally be in agreement, and the increasing amount of distillate production of the still with the added waste heat was confirmed. In addition, the optimal value of the tilt angle of glass cover and the number of cells were determined by numerical analysis.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.40 no.3
• /
• pp.93-98
• /
• 2003

With the improvement of digital signal processors, digital pulse compressor(DPC) is widely used in radar systems. The DPC can be implemented by using FIR filter algorithm in time domain or FFT algorithm in frequency domain. This paper designs an expansible DPC using multiple DSPs. With ADSP-21060 of Analog Devices Inc., the computation time as a function of the number of received range cells and FIR filter tap is compared and analyzed in time domain using C-language and assembly language. therefore, when radar system parameters are determined, the number of DSP's required to implement DPC can be easily estimated.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2006.11a
• /
• pp.150-153
• /
• 2006

Gas generator should be adopted either fuel rich or oxidizer rich combustion because of the temperature restriction to avoid any possible thermal damages to turbine blade. This study focuses to model the non-equilibrium chemical reaction of kerosene/LOx with detailed kinetics developed by Dagaut using Perfectly stirred reactor(PSR) assumption. To predict more reliable species fraction and other gas properties, Frenklach's soot model was added to Dagaut's detailed kinetics.

• Journal of Korea Water Resources Association
• /
• v.51 no.12
• /
• pp.1217-1227
• /
• 2018

This paper aims to evaluate the applicability of dam inflow prediction model using recurrent neural network theory. To achieve this goal, the Artificial Neural Network (ANN) model and the Elman Recurrent Neural Network(RNN) model were applied to hydro-meteorological data sets for the Soyanggang dam and the Chungju dam basin during dam operation period. For the model training, inflow, rainfall, temperature, sunshine duration, wind speed were used as input data and daily inflow of dam for 10 days were used for output data. The verification was carried out through dam inflow prediction between July, 2016 and June, 2018. The results showed that there was no significant difference in prediction performance between ANN model and the Elman RNN model in the Soyanggang dam basin but the prediction results of the Elman RNN model are comparatively superior to those of the ANN model in the Chungju dam basin. Consequently, the Elman RNN prediction performance is expected to be similar to or better than the ANN model. The prediction performance of Elman RNN was notable during the low dam inflow period. The performance of the multiple hidden layer structure of Elman RNN looks more effective in prediction than that of a single hidden layer structure.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.6C
• /
• pp.585-593
• /
• 2007

For the improvement of coding efficiency, the H.264 standard uses new coding tools such as VBS, 1/4-pel accurate ME, multiple references, intra prediction, loop filter, etc. Using these coding tools, H.264 has achieved significant improvements from rate-distortion point of view compared to existing standards. However, the encoder complexity is greatly increased due to these coding tools. We focus on the complexity reduction method of intra-mode decision. Our algorithm first restricts selective prediction modes of Intra4x4 using a simple preprocessing. The prediction modes of Intra4x4 are used for restricting those of the other inter-modes. Simulation results show that the proposed method outperforms other conventional methods and save about 82% of total encoding time.