Publications

Journal papers

• Hiroya, S. and Honda, M., ``Estimation of Articulatory Movements from Speech Acoustics Using an HMM-Based Speech Production Model,'' IEEE Transactions on Speech and Audio Processing, vol. 12, no. 2, pp. 175-185, 2004.
  
  We present a method that determines articulatory movements from speech acoustics using an HMM (hidden Markov model)-based speech production model. The model statistically generates speech spectrum and articulatory parameters from a given phonemic string. It consists of HMMs of articulatory parameters for each phoneme and an articulatory-to-acoustic mapping for each HMM state. For a given speech spectrum, maximum a posteriori estimation of the articulatory parameters of the statistical model is presented. The performance on sentence was evaluated by comparing the estimated articulatory parameters with the observed parameters. The average RMS errors of the estimated articulatory parameters were 1.50 mm from the speech acoustics and the phonemic information in an utterance and 1.73 mm from the speech acoustics only.
  
  
• Hiroya, S. and Honda, M., ``Speaker Adaptation Method for Acoustic-to-Articulatory Inversion using an HMM-based Speech Production Model,'' IEICE Transactions on Information and Systems, vol. E87-D, no. 5, pp. 1071-1078, 2004.
  
  We present a speaker adaptation method that makes it possible to determine articulatory parameters from an unknown speaker's speech spectrum using an HMM (hidden Markov model)-based speech production model. The model consists of HMMs of articulatory parameters for each phoneme and an articulatory-to-acoustic mapping that transforms the articulatory parameters into a speech spectrum for each HMM state. The model is statistically constructed by using actual articulatory-acoustic data. In the adaptation method, geometrical differences in the vocal tract as well as the articulatory behavior in the reference model are statistically adjusted to an unknown speaker. First, the articulatory parameters are estimated from an unknown speaker's speech spectrum using the reference model. Secondly, the articulatory-to-acoustic mapping is adjusted by maximizing the output probability of the acoustic parameters for the estimated articulatory parameters of the unknown speaker. With the adaptation method, the RMS error between the estimated articulatory parameters and the observed ones is 1.65 mm. The improvement rate over the speaker independent model is 56.1 %.
  
  
• Hiroya, S. and Mochida, T., ``Multi-speaker articulatory trajectory formation based on speaker-independent articulatory HMMs,'' Speech Communication, vol. 48, no. 12, pp. 1677-1690, 2006.
  
  Inter-speaker variability in the speech spectrum domain has been modeled using speaker-adaptive training (SAT), in which speaker-independent phoneme-specific hidden Markov models (HMMs) were used along with a speaker-adaptive matrix. In this paper, multi-speaker articulatory trajectory formation based on this method is presented. Both speaker-independent and speaker-specific features are statistically separated from a multi-speaker articulatory database, which consists of the mid-sagittal motion data of the lips, incisor, and tongue measured with an electro-magnetic articulographic (EMA) system. We evaluated the proposed method in terms of the RMS error between the measured and estimated articulatory parameters. When multi-speaker models of articulatory parameters with two speaker-adaptive matrices for each speaker were used, the average RMS error of articulatory parameters was 1.29 mm and showed no statistically significant difference from that for speaker-dependent models (1.22 mm). For comparison, multi-speaker models of the conventional speech spectrum were also constructed using a multi-speaker spectrum database, which consists of speech data simultaneously recorded during the articulatory measurements. The average spectral distance between the vocal-tract and estimated spectrum from two-matrix models was 4.19 dB and showed a statistically significant difference from that for speaker-dependent models (3.97 dB). These results indicate that modeling of inter-speaker variability in the articulatory parameter domain with a small number of matrices for each speaker almost perfectly approximates the speaker dependency of articulation and is better than that in the speech spectrum domain.
  
  
• Mochida, T., Kimura, T., Hiroya, S., Kitagawa, N., Gomi, H., and Kondo, T., ``Speech Misperception: Speaking and Seeing Interfere Differently with Hearing,'' PLoS ONE, vol. 8, no. 7, e68619. doi:10.1371/journal.pone.0068619, 2013. [pdf]
  
  
• Hiroya, S., ``Non-negative temporal decomposition of speech parameters by multiplicative update rules,'' IEEE Transactions on Audio, Speech and Language Processing, vol. 21, no. 10, pp. 2108-2117, 2013.
  
  I invented a non-negative temporal decomposition method for line spectral pairs and articulatory parameters based on the multiplicative update rules. These parameters are decomposed into a set of temporally overlapped unimodal event functions restricted to the range [0,1] and corresponding event vectors. When line spectral pairs are used, event vectors preserve their ordering property. With the proposed method, the RMS error of the measured and reconstructed articulatory parameters is 0.21 mm and the spectral distance of the measured and reconstructed line spectral pairs parameters is 2.0 dB. The RMS error and spectral distance in the proposed method are smaller than those in conventional methods. This technique will be useful for many applications of speech coding and speech modification.
  
  
• Oohashi, H., Hiroya, S., and Mochida, T., ``Real-time robust formant estimation system using a phase equalization-based autoregressive exogenous model,'' Acoustical Science and Technology, vol. 36, no. 6, pp. 478-488, 2015 [pdf]
  
  
• Igeta, T., Hiroya, S. and Arai, T., ``Overlapping of /o/ and /u/ in modern Seoul Korean - focusing on speech rate in read speech,'' Phonetics and Speech Sciences, vol. 9, no. 1, pp. 1-7, 2017.
  
  
• Igeta, T., Hiroya, S. and Arai, T., ``Overlapping of back vowels /o/ and /u/ by young Seoul Korean speakers: Focusing on the effect of preceding consonantal type and utterance unit on overlap in formant distribution,'' Journal of the Phonetic Society of Japan, vol. 21, no. 2, pp. 53-60, 2017.
  
  
• Lin, I-F., Hiroya, S., Asada, K., Ayaya, S, Kumagaya, S-I., Kato, M., "Vocal analysis of speech in adults with autism spectrum disorders," Acoustical Science and Technology, Vol. 39, No. 2, pp. 154-157, 2018. [pdf]
• Uezu, Y., Hiroya, S., Mochida, T., "Vocal-tract spectrum estimation method affects the articulatory compensation in formant transformed auditory feedback," Acoustical Science and Technology, 41(5), pp.720-728 (2020).
• Taguchi, F., Hiroya, S., Uezu, Y., Mochida, T., "Classification of formant estimation methods in transformed auditory feedback experiments using convolutional neural networks," Acoustical Science and Technology, 41(5), pp.800-803 (2020).
• Uezu, Y., Hiroya, S., Mochida, T., "Articulatory compensation for low-pass filtered formant-altered auditory feedback," The Journal of the Acoustical Society of America, vol. 150, no. 1, pp. 64-73, 2021. [pdf]
• Nagano, M., Ijima, Y., and Hiroya, S., "Perceived Emotional States Mediate Willingness to Buy from Advertising Speech," Front. Psychol. 13:1014921. doi: 10.3389/fpsyg.2022.1014921

Theses

• Graduation Thesis

  ``Numerical Solution for Linear Programming Problems Using an Affine-Scaling Method (in Japanese),'' Department of Applied Mathematics, Tokyo University of Science, February 1999.
  
  

• Master's Thesis

  ``A Study on Low Bit Rate Speech Coder Using Mixed Excitation (in Japanese),'' Department of Computational Intelligence and Systems Science, Tokyo Institute of Technology, February 2001.
  
  This paper proposes a low bit rate speech coder at 1.6 kbps. The coder uses mixed excitation which is a mixture of a periodic pulse and white noise, and mel-generalized cepstral analysis for spectral estimation. To improve the coded speech quality, we study about pitch analysis, mixture method, and gain analysis. Furthermore, we introduce jitter to a periodic pulse, periodically emphasis of noise component, and variable mel-generalized cepstral coefficients order. The result of subjective evaluation test shows that the proposed coder at 1.6 kbps is almost as good as MELP at 2.4 kbps for female speech.
  
  

• Doctoral Dissertation

  ``Estimation of Articulatory Movements from Speech Signal Using an HMM-Based Speech Production Model,'' Department of Information Processing, Tokyo Institute of Technology, August 2006. [abstract]
  

Invited talks

• Hiroya, S., ``Acoustic-to-articulatory inversion using a speaker-normalized HMM-based speech production model," in Proc. The 8th International Seminar on Speech Production, pp. 7-12, December 2008. [download from ISSP site]
• Hiroya, S., ``Verification of the motor theory of speech perception by articulatory measurements and functional brain imaging,'' in Proc. Technical Report of IEICE, vol. 109, no. 451, SP2009-162, pp. 81-86, March 2010.
• Hiroya, S., ``Neural correlates of the relationship between speech production and perception," in Proc. Acoustical Society of Japan, Spring meeting, pp. 1393-1396, March 2017.
• Hiroya, S., ``Investigation of the mechanisms of speech communication by brain science,'' in Proc. Technical Report of IEICE, vol. 117, no. 393, SP2017-75, pp. 49-54, January 2018.
• Hiroya, S., "Speech production and perception share common brain mechanisms," Joint workshop of UCL-ICN, NTT, UCL-Gatsby, and AIBS, Oct. 2018.

Invited reviews

• Honda, M., Nishikawa, K., Takanishi, A., Hiroya, S., and Mochida, T., ``Humanoid talking robot: Talking robot with mechanical vocal cords and articulators (in Japanese),'' Journal of the Acoustical Society of Japan, vol. 61, no. 2, pp. 91-96, 2005.
• Mugitani, R. and Hiroya, S., ``Development of vocal tract and acoustic features in children (in Japanese),'' Journal of the Acoustical Society of Japan, vol. 68, no. 5, pp. 234-240, 2012.
• Mugitani, R. and Hiroya, S., ``Development of vocal tract and acoustic features in children,'' Acoustical Science and Technology, vol. 33, no. 4, pp. 215-220, 2012. [pdf]
• Hiroya, S., ``Speech signal processing for speaking rhythm extraction and control (in Japanese),'' NTT Technical Journal, vol. 25, no. 9, pp. 26-29, 2013.
• Hiroya, S., ``Speaking rhythm extraction and control by non-negative temporal decomposition,'' NTT Technical Review, vol. 11, no. 12, 2013. [pdf]
• Hiroya, S., ``Formant analysis of vowels: Process and hypotheses (in Japanese),'' Journal of the Acoustical Society of Japan, vol. 70, no. 10, pp. 538-544, 2014.
• Hiroya, S., ``Brain science of "speaking and listening to speech": The relatinship between speech production and perception (in Japanese),'' Journal of the Acoustical Society of Japan, vol. 73, no. 8, pp. 509-516, 2017.

Books

• Hiroya, S., ``Auditory feedback (in Japanese),'' Acoustical Society of Japan (Eds.), Acoustic Keyword Book, Corona Publishing Co. Ltd., pp.312-313, 2016.
• Hiroya, S., ``Why can we perceive speech correctly? (in Japanese),'' Acoustical Society of Japan (Eds.), Acousticpedia for Beginners, Corona Publishing Co. Ltd., pp.140-143, 2017.
• Hiroya, S. (Ed.), Hiroya, S., Kakehi, K., Tatsumi, I., Minagawa, Y., Mochida, T. and Watanabe, M., ``The brain science of speech perception and production,'' Acoustical Society of Japan (Eds.), Acoustical Science Series, Corona Publishing Co. Ltd., 2017.

International conferences

• Brain Imaging
  • Hiroya, S. and Guenther, F.H., ``Effects of speech sound naturalness on the neural basis of formant frequency discrimination,'' Society for Neuroscience Abstracts, November 2010. [Abstracts from SfN site]
  • Hiroya, S., Jasmin, K., Evans, S., Krishnan, S., Ostarek, M., Boebinger, D., and Scott, S.K., ``Effects of speaking rhythm naturalness on the neural basis of speech perception,'' Society for Neuroscience Abstracts, November 2015. [Abstracts from SfN site]
  • Jasmin, K., Hiroya, S., Evans, S., Krishnan, S., Lima, C., Ostarek, M., Boebinger, D., and Scott, S.K., "The neural basis of perceiving speech with a non-native rhythm," 23rd Annual Meeting, Cognitive Neuroscience Society, April 2016.
  • Hiroya, S., Jasmin, K., Evans, S., Krishnan, S., Lima, C., Ostarek, M., Boebinger, D., and Scott, S.K., ``Speech rhythm measure of non-native speech using a statistical phonemic duration model,'' Society for Neurobiology of Language, August 2016.
  • Hiroya, S., Lavan, N., Chen, S.H., Meekings, S., and Scott, S.K., "Impact of articulator velocity-controlled rhythm in perceiving speech," Society for Neuroscience Abstracts, Nobember 2017. [Abstracts from SfN site]
  • Hiroya, S. and Mochida, T., ``Neural mechanisms underlying the impact of speech sound naturalness during transformed auditory feedback,'' Society for Neurobiology of Language, August 2018.
  • Hiroya, S., Cai, Q., Sethi, A., Lavan, N., Chen, S.H., Meekings, S., and Scott, S.K., "Representational similarity analysis reveals the involvement of supplementary motor area in perceiving speech rhythm," Society for Neuroscience Abstracts, Nobember 2018. [Abstracts from SfN site]
  
  
• Articulatory Measurement
  • Hiroya, S. and Kitamura, T., ``Generation of a vocal-tract MRI movie based on sparse sampling,'' in Proc. The 9th International Seminar on Speech Production, pp. 1-8, June 2011. [pdf]
  
  
• Speech Production
  • Hiroya, S. and Honda, M., ``Determination of articulatory movements from speech acoustics using an HMM-based speech production model,'' in Proc. ICASSP, pp. 437-440, May 2002.
  • Hiroya, S. and Honda, M., ``Acoustic-to-articulatory inverse mapping using an HMM-based speech production model,'' in Proc. ICSLP, pp. 2305-2308, September 2002.
  • Hiroya, S. and Honda, M., ``Speech Inversion for Arbitrary Speaker Using a Stochastic Speech Production Model,'' in Proc. An Interdisciplinary Workshop on Speech Dynamics by Ear, Eye, Mouth and Machine, pp. 9-14, June 2003.
  • Hiroya, S. and Honda, M., ``Adaptation method for a stochastic speech production model toward speech inversion,'' in Proc. The 6th International Seminar on Speech Production, pp. 91-96, December 2003.
  • Mochida, T., Hiroya, S., Honda, M., Nishikawa, K., and Takanishi, A., ``Articulatory control of talking robot by mimicking formant trajectories of human speech,'' in Proc. The 6th International Seminar on Speech Production, pp. 173-178, December 2003.
  • Hiroya, S. and Mochida, T., ``Multi-speaker articulatory reconstruction based on an eigen articulatory HMM,'' in Proc. ICASSP, pp. 909-912, March 2005.
  • Toshima, I., Hiroya, S., Mochida, T., and Gomi, H., ``Motor command invariance during speech production investigated by physiological perioral dynamics model,'' in The 9th International Seminar on Speech Production, pp. 195-202, June 2011.
  
  
• Speech Production and Perception
  • Hiroya, S., Mochida, T., and Kashino, M., ``Reducing Redundancy in Acoustic-to-Articulatory Inversion by Fundamental Frequency,'' in Proc. From Sound to Sense: 50+ years of discoveries in speech communication, pp. 19, June 2004.
  • Hiroya, S., Mochida, T., and Kashino, M., ``Articulatory gestures, not auditory frequency resolution, determine formant frequency discrimination thresholds in vowels,'' in Proc. The 29th ARO MidWinter Meeting, pp. 249, February 2006.
  • Hiroya, S., Mochida, T., and Kashino, M., ``Japanese native speakers discriminate English vowel formant frequencies better than English native speakers,'' in Proc. The 7th International Seminar on Speech Production, pp. 143-150, December 2006.
  • Mochida, T., Kimura, T., Hiroya, S., Kitagawa, N., Gomi, H. and Kondo, T., ``Effector-specific effect of self-articulatory movement on speech perception,'' Society for Neuroscience Abstracts, November 2010.
  • Mochida, T., Kimura, T., Hiroya, S., Kitagawa, N., Gomi, H. and Kondo, T., ``Effects of temporal aynchrony between sensory and articulatory events on speech perception during speech articulation,'' Society for Neuroscience Abstracts, November 2011.
  • Hiroya, S., Mochida, T., ``Speech sound naturalness alters compensation in response to transformed auditory feedback,�h in Proc. J. Acoust. Soc. Am., Vol. 140, No. 4, Pt. 2, p. 3228, November 2016.
  • Uezu, Y., Hiroya, S., and Mochida, T., "Sound naturalness of feedback speech affects articulatory compensation for transformed auditory feedback," Joint workshop of UCL-ICN, NTT, UCL-Gatsby, and AIBS, Oct. 2018.
  • Uezu, Y., Hiroya, S., and Mochida, T., "Sound naturalness of wideband speech affects articulatory compensation for altered formant feedback ," Society for Neuroscience Abstracts, Nobember 2018. [Abstracts from SfN site]
  
  
• Speech Analysis
  • Hiroya, S., ``Non-negative Temporal Decomposition of Speech Parameters,'' in Proc. ICASSP, pp. 5066-5069, March 2010. [pdf]
  • Hiroya, S. and Mochida, T., ``Phase equalization-based autoregressive model of speech signals,'' in Proc. Interspeech, pp. 42-45, September 2010. [pdf]
  • Hiroya, S., Miki, N., and Mochida, T., ``Multi-closure-interval linear prediction analysis based on phase equalization,'' in Proc. APSIPA, October 2011. [pdf]
  • Oohashi, H., Hiroya, S., and Mochida, T., ``Real-time robust formant tracking system using a phase equalization-based autoregressive exogenous model,'' in Proc. ICASSP, pp. 5118-5121, April 2015.

Domestic conferences (in Japanese)

• Brain Imaging
  • Hiroya, S. Jasmin, K., Evans, S., Krishnan, S., Lima, C., Ostarek, M., Boebinger, D., and Scott, S.K., ``Functional brain imaging for perceiving speech with a non-native rhythm,'' Proc. Acoustical Society of Japan, Spring meeting, March 2016. pp. 433-434, March 2016.
  
  
• Articulatory Measurement
  • Hiroya, S. and Kitamura, T., ``A Generation method of vocal-tract MRI movie based on sparse sampling,'' in Proc. Acoustical Society of Japan, Autumn meeting, pp. 321-324, September 2011.
  
  
• Speech Coding
  • Hiroya, S., Mashimo, S., Masuko, T., and Kobayashi, T., ``A Very Low Bit-Rate Speech Coder Using Mixed Excitation,'' in Proc. Technical Report of IEICE, SP2000-70, pp. 15-20, October 2000.
  • Hiroya, S., Masuko, T., and Kobayashi, T., ``A Study on Low Bit Rate Speech Coder Using Mixed Excitation,'' in Proc. Acoustical Society of Japan, Spring meeting, pp. 273-274, March 2001.
  
  
• Speech Production
  • Hiroya, S. and Honda, M., ``Determination of articulatory movements from speech acoustics based HMM,'' in Proc. Acoustical Society of Japan, Spring meeting, pp. 307-308, March 2002.
  • Hiroya, S. and Honda, M., ``Acoustic-to-articulatory inverse mapping using an HMM-based speech production model,'' in Proc. Acoustical Society of Japan, Autumn meeting, pp. 289-290, September 2002.
  • Hiroya, S. and Honda, M., ``A Method of Speech Inversion Using a Stochastic Speech Production Model,'' in Proc. Technical Report of IEICE, SP2002-176, pp. 41-46, January 2003.
  • Hiroya, S. and Honda, M., ``Speaker adaptation methods in speech inversion using an HMM-based speech production model,'' in Proc. Acoustical Society of Japan, Spring meeting, pp. 289-290, March 2003.
  • Hiroya, S., Mochida, T., and Honda, M., ``A relationship between articulatory positions and formant information by human articulatory-acoustic data,'' in Proc. Acoustical Society of Japan, Autumn meeting, pp. 297-298, September 2003.
  • Mochida, T., Hiroya, S., Honda, M., Nishikawa, K., and Takanishi, A., ``Articulatory control of talking robot by mimicking formant trajectories of human speech,'' in Proc. The 4th SICE System Integration Division Annual Conference, pp. 97-98, December 2003.
  • Hiroya, S., Mochida, T., and Honda, M., ``Evaluation of the estimated articulatory parameters of an unknown speaker,'' in Proc. Acoustical Society of Japan, Spring meeting, pp. 299-300, March 2004.
  • Toshima, I., Hiroya, S., and Gomi, H., ``A study of invariance during /vbv/-production investigated by physiological perioral dynamics model,'' in Proc. Technical Report of IEICE, NC2010-146, pp. 113-118, March 2011.
  • Toshima, I., Hiroya, S., Mochida, T., and Gomi, H., ``A study of invariant characteristics of motor command during speech production investigated by physiological perioral dynamics model,'' in Proc. Acoustical Society of Japan, Autumn meeting, pp. 307-308, September 2011.
  • Toshima, I., Hiroya, S., Mochida, T., and Gomi, H., ``A study of less-variant characteristics during /VCV/ speech production investigated by physiological perioral dynamics model,'' in Proc. Technical Report of IEICE, SP2011-76, pp. 43-48, November 2011.
  • Toshima, I., Hiroya, S., Mochida, T., and Gomi, H., ``Less-variant characteristics in estimated motor-command and measured EMG during the burst of stop consonants,'' in Proc. Acoustical Society of Japan, Spring meeting, pp. 325-326, March 2012.
  • Hiroya, S., ``A comparison between articulatory and acoustic parameters using NTD,'' in Proc. Acoustical Society of Japan, Spring meeting, pp. 327-328, March 2012.
  • Hiroya, S., ``Speaking rhythm conversion using non-negative temporal decomposition,'' in Proc. Auditory Research Meeting, The Acoustical Society of Japan, vol. 44, no. 2, pp. 77-80, March 2014.
  • Hiroya, S., ``Speaking rhythm conversion using non-negative temporal decomposition,'' in Proc. Acoustical Society of Japan, Autumn meeting, pp. 425-426, September 2014.
  • Hiroya, S., ``Speaking rhythm conversion of arbitrary speech using a non-negative temporal decomposition and machine learning,'' in Proc. Acoustical Society of Japan, Autumn meeting, pp. 423-424, September 2017.
  • Hiroya, S. and Mochida, T., ``Development of a robust formant perturbation system against fundamental frequency,'' in Proc. Acoustical Society of Japan, Autumn meeting, pp. 781-782, September 2018.
  • Uezu, Y., Hiroya, S. and Mochida, T., ``Inuence of sampling frequencies in formant transform auditory feedback,'' in Proc. Acoustical Society of Japan, Autumn meeting, pp. 865-866, September 2018.
  
  
• Speech Production and Perception
  • Hiroya, S., Mochida, T., and Kashino, M., ``A relationship between formant perception and articulatory gesture in vowel,'' in Proc. Acoustical Society of Japan, Autumn meeting, pp. 267-268, September 2004.
  • Hiroya, S., Mochida, T., and Kashino, M., ``A relationship between formant frequency discrimination and speaker individuality of articulatory gestures in vowels,'' in Proc. Acoustical Society of Japan, Autumn meeting, pp. 309-310, September 2005.
  • Hiroya, S., Mochida, T., and Kashino, M., ``An evaluation of vowel formant frequency discrimination thresholds predicted by an articulatory model and an auditory model,'' in Proc. Acoustical Society of Japan, Spring meeting, pp. 259-260, March 2006.
  • Hiroya, S., Mochida, T., and Kashino, M., ``Characteristics of vowel perception in English by Japanese and English native speakers: From the point of view of vowel production,'' in Proc. Acoustical Society of Japan, Autumn meeting, pp. 503-504, September 2007.
  • Mochida, T., Kimura, T., Hiroya, S., Kitagawa, N., Gomi, H. and Kondo, T., ``Impact of articulatory movement on speech perception,'' Neuro2010, September 2010.
  • Mochida, T., Kimura, T., Hiroya, S., Kitagawa, N., Gomi, H. and Kondo, T., ``Impact of self-articulatory movement on speech perception,'' 3rd Annual Meeting of Multisensory Research Forum, January 2012.
  • Mochida, T., Kimura, T., Hiroya, S., Kitagawa, N., Gomi, H. and Kondo, T., ``Effects of asynchrony between auditory and articulatory events on hearing speech with speaking,'' The 35th Annual Meeting of the Japan Neuroscience Society, September 2012.
  • Hiroya, S., ``A relationship between speaking and listening to speech: Impact of speech sound naturalness,'' Neuro2013, June 2013.
  
  
• Speech Analysis
  • Hiroya, S. and Mochida, T., ``Estimation of vocal-tract spectrum using a phase equalization-based autoregressive model,'' in Proc. Technical Report of IEICE, SP2010-76, pp. 41-46, November 2010.
  • Hiroya, S., Miki, N., and Mochida, T., ``Multi-closure-interval linear prediction analysis based on phase equalization,'' in Proc. Technical Report of IEICE, SP2011-71, pp. 13-18, November 2011.
  • Oohashi, H., Hiroya, S., and Mochida, T., ``Transformed auditory feedback system using a phase equalization-based autoregressive model,'' in Proc. Acoustical Society of Japan, Autumn meeting, pp. 277-278, September 2014.
  
  
• Speech Synthesis
  • Hiroya, S., ``LSP parameter generation algorithm preserving ordering property based on multiplicative update rules'' in Proc. Acoustical Society of Japan, Autumn meeting, pp. 293-294, September 2012.