• 대한음성학회지:말소리
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• 제52호
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• pp.101-110
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• 2004

This paper proposes a new confidence measure for utterance verification with posterior probability approximation. The proposed method approximates probabilistic likelihoods by using Viterbi search characteristics and a clustered phoneme confusion matrix. Our measure consists of the weighted linear combination of acoustic and phonetic confidence scores. The proposed algorithm shows better performance even with the reduced computational complexity than those utilizing conventional confidence measures.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(3)
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• pp.5-8
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• 2001

The computer programs based upon graphic user interface(GUI) became commonplace with the advance of computer technology. Nevertheless, programs for the visually-handicapped have still remained at the level of TTS(text to speech) programs and this prevents many visually-handicapped from enjoying the pleasure and convenience of the information age. This paper is, paying attention to the importance of character recognition in images, about the configuration of the system that converts text in the image selected by a user to the speech by extracting the character part, and carrying out character recognition.

• 대한음성학회:학술대회논문집
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• 대한음성학회 2003년도 5월 학술대회지
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• pp.32-35
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• 2003

This paper describes our recent work for developing a baseline platform for Korean spoken dialog recognition. In our work, We have collected about 65 hour speech corpus with auditory transcriptions. Linguistic information on various levels such as mophology, syntax, semantics, and discourse is attached to the speech database by using automatic or semi-automatic tools for tagging linguistic information.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1996년도 영남지부 학술발표회 논문집 Acoustic Society of Korean Youngnam Chapter Symposium Proceedings
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• pp.66-69
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• 1996

The goal of automatic speech recognition is to study techniques and systems that enable agents such that computers and robots to accept speech input. However, this paper does not provide a concrete technology in speech recognition but propose a possible mathematical tools to be employed in that area. We introduce rough set theory and suggest the possibility of the rough set approach in phonetic distinctions.

• 대한음성학회지:말소리
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• 제60호
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• pp.181-190
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• 2006

This paper describes a speech enhancement scheme that leads to significant improvements in recognition performance when used in the ASR front-end. The proposed approach is based on adaptive comb filtering and an MMSE-related parameter estimator. While adaptive comb filtering reduces noise components remarkably, it is rarely effective in reducing non-stationary noises. Furthermore, due to the uniformly distributed frequency response of the comb-filter, it can cause serious distortion to clean speech signals. This paper proposes an improved comb-filter that adjusts its spectral magnitude to the original speech, based on the speech absence probability and the gain modification function. In addition, we introduce the modified comb filtering-based speech enhancement scheme for ASR in mobile environments. Evaluation experiments carried out using the Aurora 2 database demonstrate that the proposed method outperforms conventional adaptive comb filtering techniques in both clean and noisy environments.

• 전자공학회논문지CI
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• 제41권2호
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• pp.1-8
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• 2004

자동차 텔레매틱스 용 음성 HMI(Human Machine Interface) 기술은 차량 내 음성정보기술 활용을 위하여 차량 잡음환경에 강인한 내장형 음성 기술을 통합한 음성 HMI 기반 텔레매틱스 용 DSP 시스템의 개발을 포함한다. 개발된 내장형 음성 인식엔진을 바탕으로 통합 시험을 위한 자동차 텔레매틱스 용 DSP 시스템 구현 개발을 수행하는 본 논문은 자동차용 음성 HMI의 요소 기술을 통합하는 기술 개발로 자동차용 음성 HMI 기술 개발에 중심이 되는 연구이다.

• 한국정보과학회 언어공학연구회:학술대회논문집(한글 및 한국어 정보처리)
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• 한국정보과학회언어공학연구회 2023년도 제35회 한글 및 한국어 정보처리 학술대회
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• pp.39-43
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• 2023

자동 음성 인식(Automatic Speech Recognition, ASR)은 컴퓨터가 인간의 음성을 텍스트로 변환하는 기술이다. 자동 음성 인식 시스템은 다양한 응용 분야에서 사용되며, 음성 명령 및 제어, 음성 검색, 텍스트 트랜스크립션, 자동 음성 번역 등 다양한 작업을 목적으로 한다. 자동 음성 인식의 노력에도 불구하고 노인 음성 인식(Elderly Speech Recognition, ESR)에 대한 어려움은 줄어들지 않고 있다. 본 연구는 노인 음성 인식에 콘포머(Conformer)와 피쳐 퓨전 모듈(Features Fusion Module, FFM)기반 노인 음성 인식 모델을 제안한다. 학습, 평가는 VOTE400(Voide Of The Elderly 400 Hours) 데이터셋으로 한다. 본 연구는 그동안 잘 이뤄지지 않았던 콘포머와 퓨전피쳐를 사용해 노인 음성 인식을 위한 딥러닝 모델을 제시하였다는데 큰 의미가 있다. 또한 콘포머 모델보다 높은 수준의 정확도를 보임으로써 노인 음성 인식을 위한 딥러닝 모델 연구에 기여했다.

• 대한음성학회지:말소리
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• 제67호
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• pp.181-193
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• 2008

In this paper, we propose a vocabulary coverage improvement method for embedded continuous speech recognition (CSR) using a part-of-speech (POS) tagged corpus. We investigate 152 POS tags defined in Lancaster-Oslo-Bergen (LOB) corpus and word-POS tag pairs. We derive a new vocabulary through word addition. Words paired with some POS tags have to be included in vocabularies with any size, but the vocabulary inclusion of words paired with other POS tags varies based on the target size of vocabulary. The 152 POS tags are categorized according to whether the word addition is dependent of the size of the vocabulary. Using expert knowledge, we classify POS tags first, and then apply different ways of word addition based on the POS tags paired with the words. The performance of the proposed method is measured in terms of coverage and is compared with those of vocabularies with the same size (5,000 words) derived from frequency lists. The coverage of the proposed method is measured as 95.18% for the test short message service (SMS) text corpus, while those of the conventional vocabularies cover only 93.19% and 91.82% of words appeared in the same SMS text corpus.

• 대한음성학회:학술대회논문집
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• 대한음성학회 2003년도 10월 학술대회지
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• pp.153-156
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• 2003

Voice input is often required in many new application environments such as telephone-based information retrieval, car navigation systems, and user-friendly interfaces, but the low success rate of speech recognition makes it difficult to extend its application to new fields. Popular approaches to increase the accuracy of the recognition rate have been researched by post-processing of the recognition results, but previous approaches were mainly lexical-oriented ones in post error correction. We suggest a new semantic-oriented approach to correct both semantic level and lexical errors, which is also more accurate for especially domain-specific speech error correction. Through extensive experiments using a speech-driven in-vehicle telematics information application, we demonstrate the superior performance of our approach and some advantages over previous lexical-oriented approaches.

• 대한음성학회지:말소리
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• 제53호
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• pp.103-118
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• 2005

The performance of speech recognition system is degraded by mismatch between training and test environments. Recently, Stereo-based Piecewise LInear Compensation for Environments (SPLICE) was introduced to overcome environmental mismatch using stereo data. In this paper, we propose several methods to improve the conventional SPLICE and evaluate them in the Aurora2 task. We generalize SPLICE to compensate for covariance matrix as well as mean vector in the feature space, and thereby yielding the error rate reduction of 48.93%. We also employ the weighted sum of correction vectors using posterior probabilities of all Gaussians, and the error rate reduction of 48.62% is achieved. With the combination of the above two methods, the error rate is reduced by 49.61% from the Aurora2 baseline system.