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DTSTART:20230101T000000
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DTSTART;TZID=Asia/Kolkata:20230929T100000
DTEND;TZID=Asia/Kolkata:20230929T110000
DTSTAMP:20260528T075057
CREATED:20230925T092359Z
LAST-MODIFIED:20230925T092359Z
UID:241089-1695981600-1695985200@ee.iisc.ac.in
SUMMARY:[EE Thesis Defense] - "Speech Dereverberation Using Autoregressive Models of Sub-band Envelopes"\, Anurenjan\,
DESCRIPTION:Title Dereverberation of Speech Using Autoregressive Models of Sub-band Envelopes. \nSpeaker Anurenjan P. R.  \nFaculty Advisor: Dr. Sriram Ganapathy \nExaminer : Prof. Umesh S. (IITM) \nAbstract \nThe speech-based technologies are radically changing the way we interact with systems and how we access information. In many of these applications\, the users prefer to interact with the system through a far-field microphone without the nuance of a handheld or body-worn device. Examples of such applications are automated meeting analysis\, speech-based dictation systems\, hands-free interfaces for controlling consumer-products\, IoT\, virtual assistants in mobile phones and smart speakers. The major challenge in capturing speech from the far-field is the degradation of the signal quality due to reverberation. Reverberation refers to the delayed and weighted summation of the direct component of the speech signal with the reflected versions. This talk is focused on developing methods for speech dereverberation\, i.e.\, restoring the functional quality of reverberated speech\, using autoregressive models of sub-band envelopes. signal analysis  \nThe technique of frequency domain linear prediction (FDLP) is used for finding the autoregressive model parameters.  The FDLP is the frequency domain dual of the conventional Time Domain Linear Prediction (TDLP). Just as the TDLP estimates the spectrum of a signal\, the FDLP estimates the temporal envelopes of the signal using an autoregressive model. We apply the FDLP approach to the sub-bands of speech signal that are distributed in the mel-scale. \nThis talk will describe two broad directions for addressing issues in the far-field speech using the FDLP approach. In the first part of the talk\, we explore a front-end design for automatic speech recognition (ASR) applications that suppresses the reverberation artifacts in the FDLP envelope. In the second part of the thesis\, we develop a speech enhancement model using the envelope and carrier decomposition given by the FDLP technique. \nIn the design of the ASR front end\, I will discuss a novel approach for 3-D acoustic modeling framework\, where the spatio-spectral features from all the sub-band channels are extracted. The features that are input to the 3-D CNN are extracted by modeling the signal peaks in the spatio-spectral domain using a multi-variate autoregressive modeling approach. In the subsequent part of this section\, I will describe a neural model for speech dereverberation using the long-term sub-band envelopes of speech. The neural dereverberation model estimates the envelope gain\, which when applied to reverberant signals\, allows the suppression of the late reflection components. The de-reverberated envelopes are used for feature extraction in speech recognition. The key novelty in this model is the joint learning of the reverberation and the ASR system. In these ASR experiments using the proposed framework\, we illustrate significant performance gains over previously proposed front ends.  \nThe second part of the thesis deals with the FDLP based speech dereverberation for enhancement applications\, where the goal is to restore the audible quality of the speech signal. For this task\, we decompose the sub-band speech signal into the constituent envelope and carrier part. A dereverberation neural model is designed that attempts to enhance the envelope and carrier signals jointly. Further\, joint learning of the speech enhancement model with the end-to-end ASR model is proposed with a single neural framework. The proposed model therefore can generate improved audio quality and provide robust representations for far-field ASR. Finally\, I will illustrate the subjective quality improvement of the audio signal as well as the improvement in ASR performance obtained by the proposed envelope-carrier model.     \nAcknowledgement This work was partly supported by project grants from Samsung Research India\, Bangalore and the College of Engineering\, Trivandrum\, Kerala.  \nBio Mr. Anurenjan is a PhD student at the LEAP lab\, Electrical Engineering\, IISc. He is also working as Assistant Professor in Government Engineering College\, Idukki. Mr. Anurenjan completed his Bachelors in Technology from Government Engineering College\, Barton Hill\, Trivandrum\, Kerala in 2006 and his Masters in Technology from College of Engineering\, Trivandrum\, Kerala in 2008. He joined the LEAP lab as a PhD candidate under AICTE-QIP program in the year 2017. He hails from Trivandrum district of Kerala. He is interested in signal processing\, machine learning and speech processing. Mr. Anurenjan is a member of IEEE SPS and the ISCA. During his free hours\, Mr. Anurenjan likes to play badminton and goes for swimming.  \n——- \nAll are invited. Coffee/Tea will be served before the talk. 
URL:https://ee.iisc.ac.in/event/ee-thesis-defense-speech-dereverberation-using-autoregressive-models-of-sub-band-envelopes-anurenjan/
LOCATION:MMCR\, Hall C 241\, 1st floor\, EE department
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DTSTART;TZID=Asia/Kolkata:20230929T160000
DTEND;TZID=Asia/Kolkata:20230929T173000
DTSTAMP:20260528T075057
CREATED:20230913T053937Z
LAST-MODIFIED:20230918T040821Z
UID:241060-1696003200-1696008600@ee.iisc.ac.in
SUMMARY:[EE Faculty Colloquium] Overview of Research on Pulse Width Modulation\, Motor Control and Electrical Machines
DESCRIPTION:Title: Overview of Research on Pulse Width Modulation\, Motor Control and Electrical Machines at EE\, IISc \nSpeaker: Prof. G. Narayanan\, Professor\, Electrical Engineering\, IISc \nVenue: MMCR\, EE & Online Teams link \nTime: 4pm\, 29 September 2023 \nAbstract:\nThe talk will provide a brief overview of research on pulse width modulation (PWM)\, motor control and electrical machines\, which the speaker has been a part of\, in the department of electrical engineering over the past 2-3 decades. Research highlights will be presented on the following aspects: \n\nSpace vector based PWM for motor drives and four-quadrant voltage-source converters\nOffline optimized PWM for induction motor drives\nHigh power converters for motor drives and active front-end converters\nPower-electronic control of induction motor and its variants\nEffect of inverter dead-time and its compensation\nInduction motor drive-based emulation of wind turbine\nPower electronic based emulation of electrical machines\n\nRecent and on-going activities on the following with be discussed briefly: \n\nPermanent-magnet-free high-performance motors based on reluctance principle\nHigh-speed switched reluctance motors and contact-free electromagnetic bearings\nMulti-disciplinary initiatives involving multiple departments\, multiple institutions / organizations across technical domains\n\nSpeaker’s Bio:\nG. Narayanan received his BE from College of Engineering Guindy\, Anna University\, Chennai\, in 1992; MTech from IIT Kharagpur in 1994; and PhD from IISc in 2000. He has been on the faculty of EE\, IISc\, since August 2003. He researches in the areas of power electronics\, motor drives and electrical machines. He has taught / has been teaching multiple courses in these broad domains.\n\n* All are welcome * \n—————————————-
URL:https://ee.iisc.ac.in/event/ee-faculty-colloquium-overview-of-research-on-pulse-width-modulation-motor-control-and-electrical-machines/
LOCATION:MMCR\, Hall C 241\, 1st floor\, EE department
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