Dr. T. Nagarajan

Professor and Head of Department
Department of Computer Science and Engineering

Email

Educational Qualifications

  • PDF, National Institute of Scientific Research, Montreal, Canada 
  • 2004 Ph. D – Computer Science and Engineering, IIT Madras
  • 1992 M. E – Madurai Kamaraj University

Area of Research

  • Automatic Speech Recognition
  • Text-to-Speech Synthesis
  • Speech Signal Processing
  • Acoustic Modeling
  • Machine Learning
  • Music Signal Processing

Bio

Dr. T. Nagarajan earned his PhD degree from the Computer Science and Engineering department of IIT Madras in the year 2004. In his doctoral research, he was working on spoken language identification task. After his PhD, he joined TeNet group of IITM as a Senior-project-officer. During this period, he was working on a project, named, Multimodal Interface. Subsequently, he joined the National Institute of Scientific Research (INRS), Montreal, Canada, as a postdoctoral fellow and worked there for two years. During his postdoctoral research he was focusing on Continuous speech recognition task, in which he specifically focused on discriminative training techniques for better classification. After two years of postdoctoral research, he has joined SSN College of Engineering as a professor and he has been serving SSN since 2021 and he moved to Shiv Nadar University, Chennai.

Work Experience

Experience: 30 yrs (Teaching: 23 yrs, Research: 7 yrs) 

  • 2021 – till date Professor and Head, Department of CSE, Shiv Nadar University, Chennai
  • 2009 – 2021 Professor and Head, Department of IT, SSN College of Engineering
  • 2006 – 2009 Professor, Department of IT, SSN College of Engineering
  • 2005 – 2006 Post-Doctoral Fellow, INRS, University of Quebec, Montreal, Canada
  • 2004 – 2005 Senior Project Officer, IC & SR, IIT Madras
  • 2000 – 2004 Teaching Assistant, Department of CSE, IIT Madras
  • 1995 – 2000 Assistant Professor and Head, PMC Tech, Thanjavur
  • 1992 – 1995 Senior Lecturer, PMC Tech, Thanjavu.

Projects

  • Standalone Domain-Specific Speech-to-Speech Translator for English, Hindi, and Tamil Languages, DST IMPRINT II C, Funding amount: 60Lakhs, 2023-2026
  • Real-Time Multi Dialect Automatic Speech Recognition System for Tamil, Tamil Virtual Academy, Funding amount: 13.77 Lakhs, 2023-2024
  • Prosody Modeling, Ministry of Electronics & Information Technology, Funding amount: 98.41 lakhs, 2022-2025

Ongoing:

  • Title : NLTM BHASHINI – Prosody Modelling
    Investigators : Dr. T. Nagarajan (PI), Dr. P. Vijayalakshmi (Co-PI),
    Dr. G. Anushiya Rachel (Co-PI)
    Funding Agency : Ministry of Electronics and Information Technology (MeitY)
    Fund Allocated : 98.41 lakh
    Project Duration : 2022 – 2025
    Status : Ongoing
  • Title : NLTM BHASHINI – Assistive Speech Technologies
    Investigators : Dr. P. Vijayalakshmi (PI), Dr. T. Nagarajan (Co-PI),
    Dr. M. P. Actlin Jeeva (Co-PI)
    Funding Agency : Ministry of Electronics and Information Technology (MeitY)
    Fund Allocated : 85.26 lakh
    Project Duration : 2022 – 2025
    Status : Ongoing
  • Title : Standalone Speech-to-Speech Translator for English,
    Hindi and Tamil Languages
    Investigators : Dr. T. Nagarajan (PI), Dr. P. Vijayalakshmi (Co-PI)
    Funding Agency : SERB – IMPRINT II C
    Fund Allocated : 60 Lakh
    Project Duration : 2023-2026
    Status : Ongoing
  • Title : Real-time Multi Dialect Automatic Speech Recognition
    System for Tamil
    Investigators : Dr. B. Bharathi (PI), Dr. P. Vijayalakshmi (Co-PI),
    Dr. T. Nagarajan (Co-PI)
    Funding Agency : Tamil Virtual Academy (TVA)
    Fund Allocated : 13.77 Lakh
    Project Duration : 2023-2024
    Status : Ongoing
  • Title : A multi-sensor-based bidirectional sign-language-to speech
    (BiSLATS) translation system in Tamil
    Investigators : Dr. P. Vijayalakshmi (PI), Dr. T. Nagarajan (Co-PI),
    Dr. B. Ramani (Co-PI)
    Funding Agency : DST-TIDE
    Fund Allocated : 20 lakh
    Project Duration : 2024 – 2026
    Status : Sanctioned

Completed:

  • Title : Tamil Pronunciation Error Detection Aid for Children –
    Prototype
    Investigators : Dr. T. Nagarajan (PI)
    Funding Agency : Murasu Systems Sdn Bhd, Malaysia
    Fund Allocated : 0.5 lakh
    Project Duration : 2019 – 2020
    Status : Completed
  • Title : Speech Assistive Aids for Visually Challenged People
    Investigators : Dr. T. Nagarajan (PI), Dr.P. Vijayalakshmi (Co-PI)
    Funding Agency : Tamil Virtual Academy (TVA)
    Fund Allocated : 25 lakh
    Project Duration : 2018 – 2020
    Status : Completed
  • Title : Speech-Input Speech-Output Communication Aid
    (SISOCA) for Speakers with Cerebral Palsy
    Investigators : Dr. P. Vijayalakshmi (PI), Dr. T. Nagarajan (Co-PI)
    Funding Agency : DST – TIDE
    Fund Allocated : 13.72 lakh
    Project Duration : 2017 – 2020
    Status : Completed
  • Title : Speech Enabled Interactive Enquiry System in Tamil
    Investigators : Dr. T. Nagarajan (PI), Dr. P. Vijayalakshmi (Co-PI),
    Dr. B. Bharathi(Co-PI), Ms. Sasirekha (Co-PI)
    Funding Agency : Tamil Virtual Academy (TVA)
    Fund Allocated : 9.52 lakh
    Project Duration : 2016 – 2017
    Status : Completed
  • Title : HMM-based Text-to-Speech Synthesis System for
    Malaysian Tamil
    Investigators : Dr. T. Nagarajan (PI), Dr. P. Vijayalakshmi (Co-PI)
    Funding Agency : Murasu Systems Sdn Bhd, Malaysia
    Fund Allocated : 4 lakh
    Project Duration : 2016 – 2017
    Status : Completed
  • Title : Development of Text-to-Speech Synthesis for Indian
    Languages
    Investigators : Dr. T. Nagarajan (PI), Dr. P. Vijayalakshmi (Co-PI),
    Dr. A. Shahina (Co-PI)
    Funding Agency : MeitY
    Fund Allocated : 77 lakh
    Project Duration : 2012 – 2017
    Status : Completed
  • Title : An Assessment and Intelligibility Modification System for
    Dysarthric Speakers
    Investigators : Dr. P. Vijayalakshmi (PI), Dr. T. Nagarajan (Co-PI)
    Funding Agency : All India Council for Technical Education (AICTE) –
    Research Promotion Scheme (RPS)
    Fund Allocated : 9 lakh
    Project Duration : 2010 – 2013
    Status : Completed

Publications

(Journals – 47, Conferences – 82, Book Chapters – 2)

  1. T. Lavanya, P. Vijayalakshmi, K. Mrinalini, T. Nagarajan, “Higher order statistics-driven magnitude and phase spectrum estimation for speech enhancement”, Computer Speech & Language, Vol. 87, 2024.
  2. S. Johanan Joysingh, P. Vijayalakshmi, T. Nagarajan, “Chirp Group Delay-Based Onset Detection in Instruments with Fast Attack”, Circuits, Systems, and Signal Processing, Vol. 42, Is. 3, pp. 1639–1662, 2023.
  3. T. A. Mariya Celin, P. Vijayalakshmi, T. Nagarajan, “Data Augmentation Techniques for Transfer Learning-Based Continuous Dysarthric Speech Recognition”, Circuits, Systems, and Signal Processing, Vol. 42, Is. 1, pp. 601-622, 2023.
  4. P. Vijayalakshmi, T. Nagarajan, Jayapriya Ramesh, Brathindara Suresh, Krithika Kandasamy, N. Nikhilesh, Narenraju Nagarajan, Johanan Joysingh Sathyasingh, Aiswarya Vijayakumar & Mrinalini Kannan, “Development of a low-resource wearable continuous gesture-to-speech conversion system”, Disability and Rehabilitation: Assistive Technology, Vol. 18, Is. 8, pp. 1441-1452, 2023.
  5. Nethraa Sivakumar, Pooja Srinivasan, Mrinalini Kannan, Vijayalakshmi P, Nagarajan T, “PooRaa-Agri KG: An agricultural knowledge graph-based simplified multilingual query system”, Expert Systems, Vol. 40, Is. 10, 2023.
  6. S Johanan Joysingh, P Vijayalakshmi, T Nagarajan, “Quartered Spectral Envelope and 1D-CNN-Based Classification of Normally Phonated and Whispered Speech”, Circuits, Systems, and Signal Processing, Vol. 42, Is. 5, pp. 3038-3053, 2023.
  7. N. Nanmalar, P. Vijayalakshmi, T. Nagarajan, “Literary and Colloquial Tamil Dialect Identification”, Circuits, Systems, and Signal Processing, Vol. 41, Is. 7, pp. 4004-4027, 2022.
  8. K Mrinalini, P Vijayalakshmi, T Nagarajan, “Feature-weighted AdaBoost classifier for punctuation prediction in Tamil and Hindi NLP systems”, Expert Systems, Vol. 39, Is. 4, 2022.
  9. Anushiya Rachel Gladston, S Sreenidhi, P Vijayalakshmi, T Nagarajan, “Incorporation of Happiness in Neutral Speech by Modifying Time-Domain Parameters of Emotive-Keywords”, Circuits, Systems, and Signal Processing, Vol. 41, pp. 2061–2087, 2022.
  10. K Mrinalini, P Vijayalakshmi, T Nagarajan, “SBSim: A sentence-BERT similarity-based evaluation metric for indian language neural machine translation systems”, IEEE/ACM Transactions on Audio, Speech, and Language Processing, Vol. 30, pp. 1396-1406, 2022.
  11. M Dhanalakshmi, T Nagarajan, P Vijayalakshmi, “Significant sensors and parameters in assessment of dysarthric speech”, Sensor Review, Vol. 41, Is. 3, pp. 271-286, 2021.
  12. G. Anushiya Rachel, P. Vijayalakshmi, T. Nagarajan, “Analysis of Algorithms to Estimate Glottal Closure Instants from Speech Signals”, International Journal of Speech Technology, Springer, Vol. 23, Issue 4, pp. 825 – 849, Sep. 2020.
  13. M. P. Actlin Jeeva, T. Nagarajan, P. Vijayalakshmi, “Adaptive multi‐band filter structure‐based far‐end speech enhancement”, IET Signal Processing, Vol. 14, Is. 5, pp. 288-299, 2020.
  14. T. Lavanya, T. Nagarajan, P. Vijayalakshmi, “Multi-level single-channel speech enhancement using a unified framework for estimating magnitude and phase spectra”, IEEE/ACM Transactions on Audio, Speech, and Language Processing, Vol. 28, pp. 1315-1327, 2020.
  15. T. A. Mariya Celin, T. Nagarajan, P. Vijayalakshmi, “Data augmentation using virtual microphone array synthesis and multi-resolution feature extraction for isolated word dysarthric speech recognition”, IEEE Journal of Selected Topics in Signal Processing, Vol. 14, Is, 2, pp. 346-354, 2020.
  16. T. A. Mariya Celin, G. Anushiya Rachel, T. Nagarajan, P. Vijayalakshmi, “A Weighted Speaker-Specific Confusion Transducer-Based Augmentative and Alternative Speech Communication Aid for Dysarthric Speakers”, IEEE Transactions on Neural Systems and Rehabilitation Engineering, Vol. 27, Issue 2, pp. 187 – 197, Dec. 2018.
  17. K. Mrinalini, T. Nagarajan, P. Vijayalakshmi, “Pause-Based Phrase Extraction and Effective OOV Handling for Low-Resource Machine Translation Systems”, ACM Transactions on Asian and Low Resource Language Information Processing, Vol. 18, Issue 2, pp. 1 – 22, Dec 2018.
  18. G. Anushiya Rachel, N. Sripriya, P. Vijayalakshmi, T. Nagarajan, “Significance of Differenced EGG Signal as a Spectrum in Phase-Difference Computation for the Estimation of Glottal Closure Instants”, Circuits, Systems, and Signal Processing,
    Vol. 37, Issue 5, pp. 2074 – 2097, May 2018.
  19. P. Vijayalakshmi, B. Ramani, M. P. Actlin Jeeva, T. Nagarajan, “A Multilingual to Polyglot Speech Synthesizer for Indian Languages Using a Voice-Converted Polyglot Speech Corpus”, Circuits, Systems and Signal Processing, Vol. 37, Issue 5, pp. 2142 – 2163, May 2018.
  20. M. Dhanalakshmi, T. A. Mariya Celin, T. Nagarajan, P. Vijayalakshmi, “Speech-Input Speech-Output Communication for Dysarthric Speakers Using HMM-Based Speech Recognition and Adaptive Synthesis System”, Circuits, Systems and Signal Processing, Vol. 37, Issue 2, pp. 674 – 703, Feb. 2018.
  21. G. Anushiya Rachel, P. Vijayalakshmi, T. Nagarajan, “Estimation of Glottal Closure Instants from Degraded Speech using a Phase-Difference-Based Algorithm”, Computer, Speech, and Language, Vol. 46, pp. 136 – 153, Nov. 2017.
  22. V. Sherlin Solomi, P. Vijayalakshmi, T. Nagarajan, “Exploiting Acoustic Similarities Between Tamil and Indian English in the Development of an HMM-based Bilingual Synthesizer”, IET Signal Processing, Vol. 11, Issue 3, pp. 332-340, May 2017.
  23. B. Ramani, M. P. Actlin Jeeva, P. Vijayalakshmi, T. Nagarajan, “A Multi-level GMM-Based Cross-Lingual Voice Conversion Using Language-Specific Mixture Weights for Polyglot Synthesis”, Circuits, Systems and Signal Processing, Vol. 35, pp. 1283-1311, Apr. 2016.
  24. M. P. Actlin Jeeva, T. Nagarajan, P. Vijayalakshmi, “DCT derived spectrum-based speech enhancement algorithm using temporal-domain multiband filtering”, IET Signal Processing, Vol. 10, Issue 8, pp. 965-980, Oct. 2016.
  25. G. Anushiya Rachel, V. Sherlin Solomi, K. Naveenkumar P. Vijayalakshmi and T. Nagarajan, “A small footprint context-independent HMM-based speech synthesizer for Tamil”, International Journal of Speech Technology, Vol. 18, Issue 3, pp. 405 – 418, Sep. 2015.
  26. N. Sripriya, T. Nagarajan, “Estimation of glottal closure instants considering the speech signal as a spectrum”, IET Electronic Letters, Vol. 51, Issue 8, pp. 649 – 651, Apr. 2015.
  27. B. Bharathi, T. Nagarajan, “Speaker verification using speaker-specific-text”, in WSEAS Transactions on Signal Processing, Vol. 10, pp. 320-330, July 2014.
  28. B. Bharathi, C. Arunkumar and T. Nagarajan, “Improving the performance of speaker and language identification task using unique characteristics of a class”, International Journal of Speech Technology, Vol. 16, Issue 1, pp. 115-124, 2012.
  29. P. Vijayalakshmi, T. Nagarajan and Preethi Mahadevan, “Improving speech intelligibility in cochlear implants using acoustic models”, WSEAS Transactions on Signal Processing, Vol. 7, Issue 4, pp. 103 – 116, Oct. 2011.
  30. P. Vijayalakshmi, T. Nagarajan and M. R. Reddy, “Assessment of articulatory and velopharyngeal sub-systems of dysarthric speech”, International Journal of BSCHS, special issue on Biosensors: Data acquisition, Processing and Control, Vol. 14, No. 2, pp 87 -94, Jun. 2009.
  31. G. Lakshmi Sarada, A. Lakshmi, T. Nagarajan and Hema A. Murthy, “Automatic transcription of continuous speech into syllable-like units for Indian languages”, SADHANA, Vol.34, part 2, pp. 221-233, April 2009.
  32. T. Nagarajan and Hema A. Murthy, “Language identification using acoustic log-likelihoods of syllable-like units”, Speech Communications, Elsevier publications, Vol.48, pp. 913-926, 2006.
  33. Douglas O’Shaughnessy, Wayne Wang, Willian Zhu, Vincent Barreaud, T. Nagarajan and R. Muralishankar, “Toward better automatic speech recognition”, Canadian Acoustics Journal, Vol. 33, No. 3, pp.48-49, 2005.
  34. T. Nagarajan and Hema A. Murthy, “Sub-band based Group delay segmentation of spontaneous speech into syllable-like units”, EURASIP Journal on Applied Signal Processing, Vol. 17, pp. 2612-2625, 2004.
  35. V. Kamakshi Prasad, T. Nagarajan and Hema A. Murthy, “Automatic segmentation of continuous speech using minimum phase group delay functions”, Speech Communications, Elsevier publications, Vol. 42, pp. 429-446, 2004.
  36. T. Nagarajan, V. Kamakshi Prasad and Hema A. Murthy, “The minimum phase signal derived from the root cepstrum”, IEE Electronic Letters, Vol. 39, No. 12, pp. 941-942, 2003.
  37. Higher order statistics-driven magnitude and phase spectrum estimation for speech enhancement, Computer Speech & Language, Vol. 87,T. Lavanya, P. Vijayalakshmi, K. Mrinalini, T. Nagarajan,2024
  38. Chirp Group Delay-Based Onset Detection in Instruments with Fast Attack, Circuits, Systems, and Signal Processing, Vol. 42, Is. 3, pp. 1639–1662,S. Johanan Joysingh, P. Vijayalakshmi, T. Nagarajan,2023
  39. Data Augmentation Techniques for Transfer Learning-Based Continuous Dysarthric Speech Recognition, Circuits, Systems, and Signal Processing, Vol. 42, Is. 1, pp. 601-622,T. A. Mariya Celin, P. Vijayalakshmi, T. Nagarajan,2023
  40. Development of a low-resource wearable continuous gesture-to-speech conversion system,Disability and Rehabilitation: Assistive Technology, Vol. 18, Is. 8, pp. 1441-1452,P. Vijayalakshmi, T. Nagarajan, Jayapriya Ramesh, Brathindara Suresh, Krithika Kandasamy, N. Nikhilesh, Narenraju Nagarajan, Johanan Joysingh Sathyasingh, Aiswarya Vijayakumar & Mrinalini Kannan,2023
  41. PooRaa-Agri KG: An agricultural knowledge graph-based simplified multilingual query system,Expert Systems, Vol. 40, Is. 10,Nethraa Sivakumar,  Pooja Srinivasan,  Mrinalini Kannan,  Vijayalakshmi P,  Nagarajan T,2023
  42. Quartered Spectral Envelope and 1D-CNN-Based Classification of Normally Phonated and Whispered Speech,Circuits, Systems, and Signal Processing, Vol. 42, Is. 5, pp. 3038-3053,S Johanan Joysingh, P Vijayalakshmi, T Nagarajan,2023
  43. Literary and Colloquial Tamil Dialect Identification,Circuits, Systems, and Signal Processing, Vol. 41, Is. 7, pp. 4004-4027,N. Nanmalar, P. Vijayalakshmi, T. Nagarajan,2022
  44. Feature-weighted AdaBoost classifier for punctuation prediction in Tamil and Hindi NLP systems,Expert Systems, Vol. 39, Is. 4,K Mrinalini, P Vijayalakshmi, T Nagarajan,2022
  45. Incorporation of Happiness in Neutral Speech by Modifying Time-Domain Parameters of Emotive-Keywords,Circuits, Systems, and Signal Processing, Vol. 41, pp. 2061–2087,Anushiya Rachel Gladston, S Sreenidhi, P Vijayalakshmi, T Nagarajan,2022
  46. SBSim: A sentence-BERT similarity-based evaluation metric for indian language neural machine translation systems,IEEE/ACM Transactions on Audio, Speech, and Language Processing, Vol. 30, pp. 1396-1406,K Mrinalini, P Vijayalakshmi, T Nagarajan,2022
  47. Significant sensors and parameters in assessment of dysarthric speech,Sensor Review, Vol. 41, Is. 3, pp. 271-286,M Dhanalakshmi, T Nagarajan, P Vijayalakshmi,2021
Conference Proceedings:
  1. T Lavanya, K Mrinalini, P Vijayalakshmi, T Nagarajan, “Histogram Matching based Optimized Energy Redistribution for Near End Listening Enhancement”, TENCON, Kochi, India, Oct. 2019, pp. 1307-1312.
  2. S Johanan Joysingh, P Vijayalakshmi, T Nagarajan, “Development of large annotated music datasets using HMM based forced Viterbi alignment”, TENCON, Kochi, India, Oct. 2019, pp. 1298-1302.
  3. M Nanmalar, P Vijayalakshmi, T Nagarajan, “Literary and colloquial dialect identification for Tamil using acoustic features”, TENCON, Kochi, India, Oct. 2019, pp. 1303-1306.
  4. G. Anushiya Rachel, P. Vijayalakshmi, T. Nagarajan, “Significance of Radius in the Phase-Difference-Based Approach to the Estimation of Glottal Closure Instants”, 2nd IEEE Int. Conf. on Computer, Communication and Signal Processing, Chennai, India, Feb. 2018, pp. 187 – 191.
  5. V. Aiswarya, N. Naren Raju, S. Johanan Joysingh, T. Nagarajan, P. Vijayalakshmi, “HMM based Sign Language to Speech Conversion System in Tamil”, Int. Conf. on Biosignals, Images and Instrumentation (ICBSII), Mar. 2018.
  6. M. Dhanalakshmi, T. A. Mariya Celin, T. Nagarajan, P. Vijayalakshmi, “Electromagnetic Articulograph Sensor-to-Sound Unit Mapping-Based Intelligibility Assessment of Dysarthric Speech”, IEEE TENCON, Malaysia, Nov. 2017, pp. 1784 – 1789.
  7. S. Johanan Joysingh, M. Nanmalar, G. Anushiya Rachel, V. Sherlin Solomi,
    P. Vijayalakshmi, T. Nagarajan, “Development of a Speech-Enabled Interactive Enquiry System in Tamil for Agriculture”, Tamil Internet Conference, Toronto, Canada, Aug. 2017.
  8. K. Mrinalini, G. Anushiya Rachel, T. Nagarajan, P. Vijayalakshmi, “Sentence-Medial Pause Identification for Tamil Synthesis System”, Tamil Internet Conference, Toronto, Canada, Aug. 2017.
  9. T. A. Mariya Celin, T. Nagarajan, P. Vijayalakshmi, “Dysarthric Speech Corpus in Tamil for Rehabilitation Research”, IEEE TENCON 2016, Singapore, Nov. 2016, pp. 2612 – 2615.
  10. V. Sherlin Solomi, G. Anushiya Rachel, P. Vijayalakshmi, T. Nagarajan, “Phone Mapping-based Mixed-language synthesizer for Tamil and Indian English”, Tamil Internet Conference, Gandhigram Rural Institute, Dindigul, Sep. 2016.
  11. M. P. Actlin Jeeva, T. Nagarajan, P. Vijayalakshmi, “Formant filters-based multiband speech enhancement algorithm for intelligibility improvement”, NCC, IIT Guwahati, Mar. 2016, pp. 243 – 248.
  12. M. P. Actlin Jeeva, P. Vijayalakshmi, T. Nagarajan, “Temporal-Domain Filtering Approach for Multiband Speech Enhancement”, International Conference on Microwave, Optical and Communication Engineering, IIT Bhubaneswar, Dec. 2015, pp. 385-388.
  13. G. Anushiya Rachel, P. Vijayalakshmi, T. Nagarajan, “Estimation of Glottal Closure Instants from Telephone Speech using a Group Delay-Based Approach that Considers Speech Signal as a Spectrum”, INTERSPEECH 2015, Dresden, Germany, Sep. 2015, pp. 1181-1185.
  14. I. Janani Chellam, G. Anushiya Rachel, P. Vijayalakshmi, T. Nagarajan, “Prosodic Modification of Speech to Incorporate Happy and Sad Emotions”, IEEE 4th International Conference on Computation of Power, Energy, Information and Communication (ICCPEIC-2015), Apr. 2015, pp. 183 – 188.
  15. B. Ramani, M.P. Actlin Jeeva, P. Vijayalakshmi, T. Nagarajan, “Cross-Lingual Voice Conversion-Based Polyglot Speech Synthesizer for Indian Languages”, INTERSPEECH 2014, Singapore, Sep. 2014, pp. 775 – 779.
  16. Kishore Prahallad, Anandaswarup Vadapalli, Santosh Kesiraju, Hema A Murthy, Swaran Lata, T. Nagarajan, Mahadeva Prasanna, Hemant Patil, Anil Kumar Sao, Simon King, Alan W Black and Keiichi Tokuda, “The Blizzard Challenge 2014”, Singapore, Sep. 2014.
  17. V. Sherlin Solomi, M. S. Saranya, G. Anushiya Rachel, P. Vijayalakshmi, T. Nagarajan, “Performance Comparison of KLD and PoG Metrics for Finding the Acoustic Similarity Between Phonemes for the Development of a Polyglot Synthesizer”, IEEE TENCON 2014, Bangkok, Thailand, Oct. 2014, pp. 1 – 4.
  18. G. Anushiya Rachel, S. Sreenidhi, P. Vijayalakshmi, T. Nagarajan, “Incorporation of Happiness into Neutral Speech by Modifying Emotive-Keywords”, IEEE TENCON 2014, Bangkok, Thailand, Oct. 2014, pp. 1 – 6.
  19. T. Ramya, S. Lilly Christina, P. Vijayalakshmi, T. Nagarajan, “Analysis on MAP and MLLR-Based Speaker Adaptation Technique in Speech Recognition”, IEEE Int. Conf. on Circuit, Power and Computing Technologies (ICCPCT), 2014, pp. 1753 – 1758. (Best paper award).
  20. S. Sreenidhi, G. Anushiya Rachel, P. Vijayalakshmi, T. Nagarajan, “LP and TD-PSOLA-Based Incorporation of Happiness in Neutral Speech Using Time-Domain Parameters”, IEEE Int. Conf. on Circuit, Power and Computing Technologies (ICCPCT), 2014, pp. 1158 – 1162.
  21. Jaison Thomas and T. Nagarajan, “Development and evaluation of HMM based Malayalam and English polyglot synthesizer”, 3rd National conference on Advances in Computing Technology, Sriperumbudur, March 2014, pp. 1-3.
  22. K. Naveenkumar, T. Nagarajan, “Formant and Anti-Formant estimation from chirp group delay function”, 3rd National conference on Advances in Computing Technology, Sriperumbudur, March 2014, pp. 1-5.
  23. Sivaram LP, T. Nagarajan, “Estimation of Phrase Boundaries for Tamil Speech Synthesizer”, IEEE International Conference on Innovations in Engineering and Technology (ICIET’14), March 2014, pp. 1-5.
  24. Lilly Christina, P. Vijayalakshmi and T. Nagarajan, “Cross-lingual speaker adaptation in HMM-based speech synthesis” NCC 2014, IIT Kanpur, 2014, pp. 1 – 5.
  25. Anusha Prakash, M. Ramasubba Reddy, T. Nagarajan and Hema A Murthy “An Approach to Building Language-Independent Text-to-Speech Synthesis for Indian Languages”, NCC 2014, IIT Kanpur, 2014, pp. 1 – 5.
  26. H. A. Patil, T. B. Patel, N. J. Shah, H. B. Sailor, R. Krishnan, G. R. Kasthuri, T. Nagarajan, S. L. Christina, N. Kumar, V. Raghavendra, S. P. Kishore, S. R. M. Prasanna, N. Adiga, S. R. Singh, K. Anand, P. Kumar, B. C. Singh, S. L. Binil Kumar, T. G. Bhadran, T. Sajini, A. Saha, T. Basu, K. S. Rao, N. P. Narendra, A. K. Sao, R. Kumar, P. Talukdar, P. Acharyaa, S. Chandra, S. Lata, H. A. Murthy, “A syllable-based framework for unit selection synthesis in 13 Indian languages”, Oriental COCOSDA/CASLRE 2013, Gurgaon, India, 2013, pp. 1 – 8.
  27. G. Anushiya Rachel, S. Lilly Christina, V. Sherlin Solomi, B. Ramani, P. Vijayalakshmi, T. Nagarajan, “Development and Analysis of Various Phone-Sized Unit-Based Speech Synthesizers”, Oriental COCOSDA/CASLRE 2013, Gurgaon, India, 2013, pp. 1 – 5.
  28. V. Sherlin Solomi, S. Lilly Christina, G. Anushiya Rachel, B. Ramani, P. Vijayalakshmi, T. Nagarajan, “Analysis on Acoustic Similarities between Tamil and English Phonemes using Product of Likelihood-Gaussians for an HMM-Based Mixed-Language Synthesizer”, Oriental COCOSDA/CASLRE 2013, Gurgaon, India, 2013, pp. 1 – 5.
  29. N. Sripriya, T. Nagarajan, “Estimation of instants of significant excitation using accumulated energy function of DCT”, Oriental COCOSDA/CASLRE 2013, Gurgaon, India, Nov 25-27, 2013, pp. 1 – 6.
  30. Ramani B, Actlin Jeeva M P, Vijayalakshmi P, Nagarajan T, “Voice Conversion-based Multilingual to Polyglot Speech Synthesizer for Indian Languages”, IEEE TENCON 2013, Xi’an, China, 2013, pp. 1 – 4.
  31. B. Bharathi and T. Nagarajan “GMM and i-vector based speaker verification using speaker-specific-text for short utterances”, IEEE TENCON 2013, at Xi’an, China, 22-25, Oct. 2013, pp. 1 – 4.
  32. B. Ramani, S. Lilly Christina, G. Anushiya Rachel, V. Sherlin Solomi, Mahesh Kumar Nandwana, Anusha Prakash, Aswin Shanmugam, Raghava Krishnan, S. Kishore Prahalad, K.Samudravijaya, P. Vijayalakshmi, T. Nagarajan and Hema Murthy, “A Common Attribute based Unified HTS Framework for Speech Synthesis in Indian Languages”, ISCA – SSW8, Barcelona, Spain , 2013, pp. 291 – 296.
  33. N. Sripriya, T. Nagarajan, “Pitch Estimation using Harmonic Product Spectrum derived from DCT”, IEEE TENCON 2013, China, Oct 22-25, 2013, pp. 1 – 4.
  34. M. Anbu Swarna Priyanka, V. Sherlin Solomi, P. Vijayalakshmi, T. Nagarajan, “Multiresolution Feature Extraction (MRFE) based speech recognition system”, International Conference on Recent Trends in Information Technology (ICRTIT), Chennai, July 2013, pp. 152-156.
  35. S. Magdalene Mahiba, S. Lilly Christina, P. Vijayalakshmi, T. Nagarajan, “Analysis of Cross-Gender Adaptation using MAP and MLLR in Speech Recognition System”, International Conference on Recent Trends in Information Technology (ICRTIT), Chennai, 25-27 July 2013, pp. 387-392.
  36. B. Ramani, V. Sherlin Solomi, G. Anushiya Rachel, S. Lilly Christina, P. Vijayalakshmi, T. Nagarajan, Hema A Murthy, “Development and Evaluation of Unit Selection and HMM-based Speech Synthesis for Tamil”, NCC 2013, Delhi, India, 2013, pp. 1 – 5.
  37. B. Bharathi and T. Nagarajan, “A two-level approach for speaker recognition using speaker-specific-text”, NCC 2013, IIT Delhi, Feb. 2013, pp. 1 – 4.
  38. M. Nanmalar, T. Nagarajan, “Multilingual Speech Recognition System for Indian Languages”, National Conference on Signal Processing, Communication Engineering (NCSCV 13), Anna University, Coimbatore, May 2013, pp. 344 – 349.
  39. Anusha, T. Nagarajan, “Prosody modeling for Tamil text-to-speech systems in FestVox framework”, National Conference on Signal Processing, Communication Engineering (NCSCV 13), Anna University, Coimbatore, May 2013.
  40. M. S. Saranya, T. Nagarajan,” Bilingual Text to Speech Synthesis Using HTS, National Trends in VLSI, Information and Communication, Dr. B. S. Abdur Rahman University, Chennai, Apr. 2013, pp. 1 – 5.
  41. K. Menaga, T. Nagarajan, “Development and Performance Analysis of Phoneme and CV-based Tamil Unit Selection Synthesis Systems”, ICCCC’13, Christian College of Engineering and Technology, Oddanchatram, Apr. 2013.
  42. M. Anbu Swarna Priyanka, V. Sherlin Solomi, P. Vijayalakshmi, T. Nagarajan, “Speech recognition system developed using Multiresolution Feature Extraction (MRFE) for sparse data”, National Conf. on Signal Processing, Communication and VLSI Design (NCSCV’13), Anna University, Coimbatore, May 2013, pp. 302 – 306.
  43. S. Magdalene Mahiba, S. Lilly Christina, P. Vijayalakshmi, T. Nagarajan, “Speaker Adaptation Using MLLR and MAP Techniques in Speech Recognition System”, National Conf. on Signal Processing, Communication and VLSI Design (NCSCV’13), Anna University, Coimbatore, May 2013, pp. 350 – 353.
  44. S. Johanan Joy Singh, G. Anushiya Rachel, P. Vijayalakshmi, T. Nagarajan, “Incorporating Emotions into Neutral Speech by Modifying Glottal Closure Instants”, National Conf. on Signal Processing, Communication and VLSI Design (NCSCV’13), Anna University, Coimbatore, May 2013, pp. 339 – 343.
  45. M. Saranya, P. Vijayalakshmi and T. Nagarajan, “Improving the Intelligibility of Dysarthric Speech by Modifying System Parameters, Retaining Speaker’s Identity”, Proc. of the Second International Conference on Recent Trends in Information Technology, Apr. 2012, pp. 60 – 65.
  46. S. Lilly Christina, P. Vijayalakshmi and T. Nagarajan, “HMM Based Speech Recognition System for the Dysarthric Speech Evaluation of Articulatory Subsystem”, Second International Conference on Recent Tends in Information Technology, Apr. 2012, pp. 54 – 59.
  47. Anushiya Rachel Gladston, P. Vijayalakshmi and T. Nagarajan, “Improving Speech Intelligibility in Cochlear Implants Using Vocoder-Centric Acoustic Models”, Second International Conference on Recent Trends in Information Technology, Apr. 2012, pp. 66 – 71.
  48. P. Vijayalakshmi, B. Bharathi, T. Nagarajan, “Reducing the complexity of a triphone- based speech recognition system based on degree of coarticulation”, IEEE Technical symposium, IIT Kharagpur, Jan. 2011.
  49. B. Bharathi, P. Vijayalakshmi, T. Nagarajan “Speaker identification using utterances correspond to speaker-specific-text”, IEEE Technical symposium, IIT Khargpur, Jan. 2011.
  50. Saranya A, Sripriya N, T. Nagarajan, “Design of a VOCODER using instants of significant excitation”, International conference on Signal Processing, Communication, Computing and Network Technologies (ICSCCN-2011), July 2011, pp.742-746
  51. T. Monica and T. Nagarajan, “Segmentation of speech signal into phonemes using two-level GMM-tokenization”, International Conference on Recent Trends in Information Technology, ICRTIT 2011, MIT, Chennai, Jun. 2011, pp. 843-847.
  52. Preethi M, Pavithra B, Shriranjani S, Vijayalakshmi P, and T. Nagarajan, “Cochlear Implant model using Mel-frequency cepstral coefficients”, Intl. conference on Implantable Auditory Prosthesis (CIAP) 2011, Jul. 2011, California.
  53. Preethi Mahadevan, T. Nagarajan, Pavithra B, S Shri Ranjani, Vijayalakshmi P, “Design of a lab model of a Digital Speech Processor for cochlear implant”, TENCON 2011, Indonesia, 2011, pp. 307 – 311
  54. P. Vijayalakshmi, Anu Abraham, B. Bharathi and T. Nagarajan, “Reducing the complexity of a triphone-based speech recognition system based on degree of coarticulation”, IEEE Techsym 2011, Jan. 2011, pp. 175 – 179.
  55. S. Harish, P. Vijayalakshmi and T. Nagarajan, “Significance of segmentation in Phoneme-based Tamil speech recognition system”, IEEE – ICECT, Apr. 2011, pp. 221 – 225.
  56. Anu Abraham, P. Vijayalakshmi and T. Nagarajan, “Pole focused linear prediction based spectrogram for coarticulation analysis”, IEEE Techsym 2010, IIT Kharagpur, Feb. 2010.
  57. C. Arun Kumar, B. Bharathi, and T. Nagarajan, “A Discriminative GMM Technique using Product of Likelihood Gaussians”, IEEE TENCON 2009, Singapore, Aug. 2009.
  58. P. Vijayalakshmi, P. Mukesh Kumar, Ra. V. Jayanthan and T. Nagarajan, “Cochlear Implant Models Based on Critical Band Filters”, IEEE TENCON 2009, Singapore, Aug. 2009.
  59. P. Vijayalakshmi, T. Nagarajan and Ra. V. Jayanthan, “Selective Pole Modification-Based Technique for the Analysis and Detection of Hypernasality”, IEEE TENCON 2009, Singapore, Aug. 2009.
  60. N. Sripriya, P. Vijayalakshmi, C. Arun Kumar and T. Nagarajan – “Estimation of instants of significant excitation from speech signal using temporal phase periodicity” – IEEE TENCON 2009, Nov. 2009, pp. 1 – 4.
  61. T. Nagarajan, and P. Vijayalakshmi, “Discriminative optimization of HMM Topology using product of likelihood – Gaussians”, National Conference on Communications, IIT Mumbai, 2008.
  62. T. Nagarajan and Douglas O’Shaughnessy, “Bias estimation and correction in a classifier using product of likelihood-Gaussians”, ICASSP – 2007, Hawaii, USA, pp. 1061-1064.
  63. T. Nagarajan and Douglas O’Shaughnessy, “Discriminative MLE training using a product of Gaussian likelihoods”, INTERSPEECH – 2006, Pittsburgh, USA, Sep. 2006, pp. 601-604.
  64. T. Nagarajan, P. Vijayalakshmi, and Douglas O’Shaughnessy, “Combining multiple-sized sub-word units in a speech recognition system using baseform selection”, INTERSPEECH – 2006, Pittsburgh, USA, Sep. 2006, pp. 1595 – 1597.
  65. Douglas O’Shaughnessy, T. Nagarajan, and Li Haozheng, “Better model and decoding methods for automatic speech recognition”, Acoustic Society of America – 151st Meeting, Jun. 2006.
  66. Douglas O’Shaughnessy, Wayne Wang, Willian Zhu, Vincent Barreaud, T. Nagarajan and R. Muralishankar, “Improving automatic speech recognition via better analysis and adaptation”, Acoustic Society of America – 150th Meeting, Vol.118, No. 3, Sep. 2005.
  67. T. Nagarajan and Douglas O’Shaughnessy, “Explicit segmentation of speech based on frequency-domain AR modeling”, INTERSPEECH – 2005, Lisbon, Portugal, Sep. 2005, pp. 653-656.
  68. G. L. Sarada, T. Nagarajan, Hema A. Murthy, “Multiple Frame Size and Multiple Frame Rate Feature Extraction for Continuous Speech Recognition”, SPCOM-2004, Bangalore, Dec. 2004, pp 592-595.
  69. N. Hemalatha, G. L. Sarada, T. Nagarajan, Hema A. Murthy, “Connected Digit Recognition using Unsupervised and Incremental HMMs”, NCC-2005, IIT Kharagpur, India, Jan 2005, pp. 296-299.
  70. M. Nageshwara Rao, S. Thomas, T. Nagarajan and H. A. Murthy, “Text-to-speech synthesis using syllable-like units”, NCC-2005, IIT Kharagpur, India, Jan 2005, pp 277-280.
  71. P. Sowjanya, K. Vijayalakshmi, G. Vijay Prakash, Kasi Rajan, M. S. Vidhya,
    T. Nagarajan, Srinivas Chakravarthy, N. S. Narayanaswamy and Hema A. Murthy, “Hand Writing Interface enabled Tamil Search Engine”, 11’th National Conference on Communications, IIT Kharagpur, Jan. 2005, pp 661-665.
  72. G. L. Sarada, T. Nagarajan, and Hema A. Murthy, “Automatic Transcription of continuous speech Using Unsupervised and Incremental Training”, INTERSPEECH – 2004, South Korea, Oct. 2004, pp. 405-408.
  73. T. Nagarajan, Hema A. Murthy and N. Hemalatha, “Automatic segmentation and labeling of continuous speech without bootstrapping”, EUSIPCO-2004, Vienna, Austria, Sep. 2004, pp. 561-564.
  74. T. Nagarajan and Hema A. Murthy, “Language identification using parallel syllable-like unit recognition”, ICASSP-2004, Montreal, Canada, May 2004, Vol. I, pp. 401-404.
  75. T. Nagarajan and Hema A. Murthy, “An approach to segmentation and labeling of continuous speech without bootstrapping”, Proc. NCC-2004, IISc, Bangalore, India, Jan. 2004, pp. 508-512.
  76. T. Nagarajan, Hema A. Murthy, and, Rajesh M. Hegde, “Segmentation of speech into syllable-like units”, Proc. EUROSPEECH-03, Geneva, Switzerland, Sep. 2003, pp. 2893-2896.
  77. T. Nagarajan and Hema A. Murthy, “Group delay based segmentation of spontaneous speech into syllable-like units”, ISCA and IEEE workshop on Spontaneous Speech Processing and Recognition, Tokyo, Japan, Apr. 2003, pp. 115-118.
  78. T. Nagarajan and Hema A. Murthy, “A pair-wise multiple codebook approach to implicit language identification”, Workshop on Spoken Language Processing, TIFR, India, Jan. 2003, pp.101-108.
  79. T. Nagarajan and Hema A. Murthy, “Language identification using spectral vector distribution across languages”, Proc. International Conference on Natural Language Processing, Dec. 2002, pp. 327-335.
  80. V. Kamakshi Prasad, T. Nagarajan and Hema A. Murthy, “Continuous speech recognition using automatically segmented data at syllabic units”, Proc. ICSP-2002, China, 2002, pp. 235-238.
  81. T. Nagarajan, V. Kamakshi Prasad, and Hema A. Murthy, “The minimum phase signal derived from the magnitude spectrum and its applications to speech segmentation”, Sixth Biennial Conference on Signal Processing and Communications, Bangalore, India, Jul. 2001, pp. 95-101.
  82. Jyotsna Balleda, Hema A. Murthy, and T. Nagarajan, “Language identification from short segment of speech”, Proc. ICSLP-2000, Vol. III, pp.1033-1036.
Book Chapters:
  1. P. Vijayalakshmi, T. Nagarajan, “Assessment and intelligibility modification for dysarthric speakers”, Chapter 3 – Voice Technologies for Reconstruction and Enhancement, De Gruyter Series in Speech Technology and Text Mining in Medicine and Healthcare, pp. 67 – 94, Feb. 2020.
  2. P. Vijayalakshmi, T. A. Mariya Celin, T. Nagarajan, “Selective pole modification-based technique for the analysis and detection of hypernasality”, Chapter 2 – Signal and Acoustic Modeling for Speech and Communication Disorders, De Gruyter Series in Speech Technology and Text Mining in Medicine and Healthcare, pp. 33 – 68, Dec. 2018.

 

  1. Higher order statistics-driven magnitude and phase spectrum estimation for speech enhancement, Computer Speech & Language, Vol. 87,T. Lavanya, P. Vijayalakshmi, K. Mrinalini, T. Nagarajan,2024
  2. Chirp Group Delay-Based Onset Detection in Instruments with Fast Attack, Circuits, Systems, and Signal Processing, Vol. 42, Is. 3, pp. 1639–1662,S. Johanan Joysingh, P. Vijayalakshmi, T. Nagarajan,2023
  3. Data Augmentation Techniques for Transfer Learning-Based Continuous Dysarthric Speech Recognition, Circuits, Systems, and Signal Processing, Vol. 42, Is. 1, pp. 601-622,T. A. Mariya Celin, P. Vijayalakshmi, T. Nagarajan,2023
  4. Development of a low-resource wearable continuous gesture-to-speech conversion system,Disability and Rehabilitation: Assistive Technology, Vol. 18, Is. 8, pp. 1441-1452,P. Vijayalakshmi, T. Nagarajan, Jayapriya Ramesh, Brathindara Suresh, Krithika Kandasamy, N. Nikhilesh, Narenraju Nagarajan, Johanan Joysingh Sathyasingh, Aiswarya Vijayakumar & Mrinalini Kannan,2023
  5. PooRaa-Agri KG: An agricultural knowledge graph-based simplified multilingual query system,Expert Systems, Vol. 40, Is. 10,Nethraa Sivakumar,  Pooja Srinivasan,  Mrinalini Kannan,  Vijayalakshmi P,  Nagarajan T,2023
  6. Quartered Spectral Envelope and 1D-CNN-Based Classification of Normally Phonated and Whispered Speech,Circuits, Systems, and Signal Processing, Vol. 42, Is. 5, pp. 3038-3053,S Johanan Joysingh, P Vijayalakshmi, T Nagarajan,2023
  7. Literary and Colloquial Tamil Dialect Identification,Circuits, Systems, and Signal Processing, Vol. 41, Is. 7, pp. 4004-4027,N. Nanmalar, P. Vijayalakshmi, T. Nagarajan,2022
  8. Feature-weighted AdaBoost classifier for punctuation prediction in Tamil and Hindi NLP systems,Expert Systems, Vol. 39, Is. 4,K Mrinalini, P Vijayalakshmi, T Nagarajan,2022
  9. Incorporation of Happiness in Neutral Speech by Modifying Time-Domain Parameters of Emotive-Keywords,Circuits, Systems, and Signal Processing, Vol. 41, pp. 2061–2087,Anushiya Rachel Gladston, S Sreenidhi, P Vijayalakshmi, T Nagarajan,2022
  10. SBSim: A sentence-BERT similarity-based evaluation metric for indian language neural machine translation systems,IEEE/ACM Transactions on Audio, Speech, and Language Processing, Vol. 30, pp. 1396-1406,K Mrinalini, P Vijayalakshmi, T Nagarajan,2022
  11. Significant sensors and parameters in assessment of dysarthric speech,Sensor Review, Vol. 41, Is. 3, pp. 271-286,M Dhanalakshmi, T Nagarajan, P Vijayalakshmi,2021

Awards

2020 – Chief Minister’s Award for Tamil Computing for the year 2019, from the government of Tamil Nadu, for his contribution to Tamil for building a lightweight HMM-Based speech synthesizer and developing various applications.

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