• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2009년도 추계학술발표대회
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• pp.239-240
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• 2009

We live in a flat world in which globalization fosters communication, travel, and trade among more than 150 countries and thousands of languages. To surmount the barriers among these languages, translation is required; Speech-to-Speech translation will automate the process. Thanks to recent advances in Automatic Speech Recognition (ASR), Machine Translation (MT), and Text-to-Speech (TTS), one can now utilize a system to translate a speech of source language to a speech of target language and vice versa in affordable manner. The three phase process establishes that the source speech be transcribed into a (set of) text of the source language (ASR) before the source text is translated into the target text (MT). Finally, the target speech is synthesized from the target text (TTS).

• 한국정보처리학회논문지
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• 제3권5호
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• pp.1121-1129
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• 1996

Text-to-Speech 시스템에서 자연스럽게 음성을 합성하기 위해서는 운율과 길이 에 대한 처리가 선행되어야 한다. 이를 위해서, 자연어 처리에 의해 분석된 문장들에 대해 억양 규칙을 적용한 후, 반복적인 실험을 통해 운율 및 길이 정보를 추출하였다. 본 논문에서는 이러한 정보를 이용하여 Text-to-Speech 시스템에서 자연성을 향상 시 킬 수 있는 방법을 제안한다. 실험 결과, 본 논문에서 제안하고 구현한 무제한 Text- to-Speech 시스템이 이러한 정보들을 사용하지 않는 시스템과 비교해서 더 자연스럽게 문장들을 합성해 낸다는 것을 보였다.

• 음성과학
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• 제15권4호
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• pp.97-105
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• 2008

Nowadays an HMM-based text-to-speech system (HTS) has been very widely studied because it needs less memory and low computation complexity and is suitable for embedded systems in comparison with a corpus-based unit concatenation text-to-speech one. It also has the advantage that voice characteristics and the speaking rate of the synthetic speech can be converted easily by modifying HMM parameters appropriately. We implemented an HMM-based Korean text-to-speech system using a small size Korean speech DB and proposes a method to increase the naturalness of the synthetic speech by controlling duration model parameters in the HMM-based Korean text-to speech system. We performed a paired comparison test to verify that theses techniques are effective. The test result with the preference scores of 73.8% has shown the improvement of the naturalness of the synthetic speech through controlling the duration model parameters.

• 음성과학
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• 제14권2호
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• pp.91-103
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• 2007

The purpose of this paper is to develop a model enabling to predict the prosody of Korean text-to-speech synthesis using the CART and SKES algorithms. CART prefers a prediction variable in many instances. Therefore, a partition method by F-Test was applied to CART which had reduced the number of instances by grouping phonemes. Furthermore, the quality of the text-to-speech synthesis was evaluated after applying the SKES algorithm to the same data size. For the evaluation, MOS tests were performed on 30 men and women in their twenties. Results showed that the synthesized speech was improved in a more clear and natural manner by applying the SKES algorithm.

• 한국컴퓨터정보학회논문지
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• 제29권1호
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• pp.41-49
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• 2024

현재 음성인식 기술은 꾸준히 발전하고 다양한 분야에서 널리 사용되고 있다. 본 연구에서는 음성 데이터 품질이 음성인식 모델에 미치는 영향을 알아보기 위해 데이터셋을 전체 데이터셋과 SNR 상위 70%의 데이터셋으로 나눈 후 Seamless M4T와 Google Cloud Speech-to-Text를 이용하여 각 모델의 텍스트 변환 결과를 확인하고 Levenshtein Distance를 사용하여 평가하였다. 실험 결과에서 Seamless M4T는 높은 SNR(신호 대 잡음비)을 가진 데이터를 사용한 모델에서 점수가 13.6으로 전체 데이터셋의 점수인 16.6보다 더 낮게 나왔다. 그러나 Google Cloud Speech-to-Text는 전체 데이터셋에서 8.3으로 높은 SNR을 가진 데이터보다 더 낮은 점수가 나왔다. 이는 새로운 음성인식 모델을 훈련할 때 SNR이 높은 데이터를 사용하는 것이 영향이 있다고 할 수 있으며, Levenshtein Distance 알고리즘이 음성인식 모델을 평가하기 위한 지표 중 하나로 쓰일 수 있음을 나타낸다.

• 말소리와 음성과학
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• 제10권1호
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• pp.39-48
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• 2018

A typical statistical parametric speech synthesis (text-to-speech, TTS) system consists of separate modules, such as a text analysis module, an acoustic modeling module, and a speech synthesis module. This causes two problems: 1) expert knowledge of each module is required, and 2) errors generated in each module accumulate passing through each module. An end-to-end TTS system could avoid such problems by synthesizing voice signals directly from an input string. In this study, we implemented an end-to-end Korean TTS system using Google's Tacotron, which is an end-to-end TTS system based on a sequence-to-sequence model with attention mechanism. We used 4392 utterances spoken by a Korean female speaker, an amount that corresponds to 37% of the dataset Google used for training Tacotron. Our system obtained mean opinion score (MOS) 2.98 and degradation mean opinion score (DMOS) 3.25. We will discuss the factors which affected training of the system. Experiments demonstrate that the post-processing network needs to be designed considering output language and input characters and that according to the amount of training data, the maximum value of n for n-grams modeled by the encoder should be small enough.

• ETRI Journal
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• 제42권5호
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• pp.761-772
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• 2020

This paper presents an automatic proficiency assessment method for a non-native Korean read utterance using bidirectional long short-term memory (BLSTM)-based acoustic models (AMs) and speech data augmentation techniques. Specifically, the proposed method considers two scenarios, with and without prompted text. The proposed method with the prompted text performs (a) a speech feature extraction step, (b) a forced-alignment step using a native AM and non-native AM, and (c) a linear regression-based proficiency scoring step for the five proficiency scores. Meanwhile, the proposed method without the prompted text additionally performs Korean speech recognition and a subword un-segmentation for the missing text. The experimental results indicate that the proposed method with prompted text improves the performance for all scores when compared to a method employing conventional AMs. In addition, the proposed method without the prompted text has a fluency score performance comparable to that of the method with prompted text.

• 음성과학
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• 제10권4호
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• pp.167-177
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• 2003

This paper presents a method of building an exceptional pronunciation dictionary for Korean automatic pronunciation generator. An automatic pronunciation generator is an essential element of speech recognition system and a TTS (Text-To-Speech) system. It is composed of a part of regular rules and an exceptional pronunciation dictionary. The exceptional pronunciation dictionary is created by extracting the words which have exceptional pronunciations from text corpus based on the characteristics of the words of exceptional pronunciation through phonological research and text analysis. Thus, the method contributes to improve performance of Korean automatic pronunciation generator as well as the performance of speech recognition system and TTS system.

• ETRI Journal
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• 제46권1호
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• pp.96-105
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• 2024

We propose a method to automatically predict Alzheimer's disease from speech data using the ChatGPT large language model. Alzheimer's disease patients often exhibit distinctive characteristics when describing images, such as difficulties in recalling words, grammar errors, repetitive language, and incoherent narratives. For prediction, we initially employ a speech recognition system to transcribe participants' speech into text. We then gather opinions by inputting the transcribed text into ChatGPT as well as a prompt designed to solicit fluency evaluations. Subsequently, we extract embeddings from the speech, text, and opinions by the pretrained models. Finally, we use a classifier consisting of transformer blocks and linear layers to identify participants with this type of dementia. Experiments are conducted using the extensively used ADReSSo dataset. The results yield a maximum accuracy of 87.3% when speech, text, and opinions are used in conjunction. This finding suggests the potential of leveraging evaluation feedback from language models to address challenges in Alzheimer's disease recognition.

• 한국컴퓨터정보학회논문지
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• 제26권12호
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• pp.105-110
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• 2021

본 논문에서는 STT(Speech-to-Text), TTS(Text-to-Speech) API와 가속도 센서 기반의 청각 장애인의 의사소통을 도와주는 안드로이드 모바일 애플리케이션을 설계하고 구현한다. 이 애플리케이션은 청각 장애인의 대화 상대가 말하는 것을 마이크로 녹음하고 STT API를 이용하여 텍스트로 변환하여 청각 장애인에게 보여주는 기능을 제공한다. 또한, TTS API를 이용하여 청각 장애인이 문자를 입력하면 음성으로 변환하여 대화 상대에게 들려준다. 청각 장애인이 스마트폰을 흔들면 이 애플리케이션이 실행하도록 가속도 센서 기반의 백그라운드 서비스 기능을 제공한다. 본 논문에서 구현한 애플리케이션은 청각 장애인들이 다른 사람과 의사소통을 할 때 영상통화로 수화를 이용하지 않고 쉽게 대화할 수 있는 기능을 제공한다.