• Title/Summary/Keyword: log-likelihood ratio accumulation

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A Study on Utterance Verification Using Accumulation of Negative Log-likelihood Ratio (음의 유사도 비율 누적 방법을 이용한 발화검증 연구)

  • 한명희;이호준;김순협
    • The Journal of the Acoustical Society of Korea
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    • v.22 no.3
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    • pp.194-201
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    • 2003
  • In speech recognition, confidence measuring is to decide whether it can be accepted as the recognized results or not. The confidence is measured by integrating frames into phone and word level. In case of word recognition, the confidence measuring verifies the results of recognition and Out-Of-Vocabulary (OOV). Therefore, the post-processing could improve the performance of recognizer without accepting it as a recognition error. In this paper, we measure the confidence modifying log likelihood ratio (LLR) which was the previous confidence measuring. It accumulates only those which the log likelihood ratio is negative when integrating the confidence to phone level from frame level. When comparing the verification performance for the results of word recognizer with the previous method, the FAR (False Acceptance Ratio) is decreased about 3.49% for the OOV and 15.25% for the recognition error when CAR (Correct Acceptance Ratio) is about 90%.

Improved Reliability-Based Iterative Decoding of LDPC Codes Based on Dynamic Threshold

  • Ma, Zhuo;Du, Shuanyi
    • ETRI Journal
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    • v.37 no.4
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    • pp.736-742
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    • 2015
  • A serial concatenated decoding algorithm with dynamic threshold is proposed for low-density parity-check codes with short and medium code lengths. The proposed approach uses a dynamic threshold to select a decoding result from belief propagation decoding and order statistic decoding, which improves the performance of the decoder at a negligible cost. Simulation results show that, under a high SNR region, the proposed concatenated decoder performs better than a serial concatenated decoder without threshold with an Eb/N0 gain of above 0.1 dB.