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Pitch-scale modification using the modulated aspiration noise source

Published in:
INTERSPEECH, 17-21 September 2006.

Summary

Spectral harmonic/noise component analysis of spoken vowels shows evidence of noise modulations with peaks in the estimated noise source component synchronous with both the open phase of the periodic source and with time instants of glottal closure. Inspired by this observation of natural modulations and of fullband energy in the aspiration noise source, we develop an alternate approach to high-quality pitch-scale modification of continuous speech. Our strategy takes a dual processing approach, in which the harmonic and noise components of the speech signal are separately analyzed, modified, and re-synthesized. The periodic component is modified using standard modification techniques, and the noise component is handled by modifying characteristics of its source waveform. Since we have modeled an inherent coupling between the periodic and aspiration noise sources, the modification algorithm is designed to preserve the synchrony between temporal modulations of the two sources. The reconstructed modified signal is perceived in informal listening to be natural-sounding and typically reduces artifacts that occur in standard modification techniques.
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Summary

Spectral harmonic/noise component analysis of spoken vowels shows evidence of noise modulations with peaks in the estimated noise source component synchronous with both the open phase of the periodic source and with time instants of glottal closure. Inspired by this observation of natural modulations and of fullband energy in the...

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Missing feature theory with soft spectral subtraction for speaker verification

Published in:
Interspeech 2006, ICSLP, 17-21 September 2006.

Summary

This paper considers the problem of training/testing mismatch in the context of speaker verification and, in particular, explores the application of missing feature theory in the case of additive white Gaussian noise corruption in testing. Missing feature theory allows for corrupted features to be removed from scoring, the initial step of which is the detection of these features. One method of detection, employing spectral subtraction, is studied in a controlled manner and it is shown that with missing feature compensation the resulting verification performance is improved as long as a minimum number of features remain. Finally, a blending of "soft" spectral subtraction for noise mitigation and missing feature compensation is presented. The resulting performance improves on the constituent techniques alone, reducing the equal error rate by about 15% over an SNR range of 5 - 25 dB.
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Summary

This paper considers the problem of training/testing mismatch in the context of speaker verification and, in particular, explores the application of missing feature theory in the case of additive white Gaussian noise corruption in testing. Missing feature theory allows for corrupted features to be removed from scoring, the initial step...

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An overview of automatic speaker diarization systems

Published in:
IEEE Trans. Audio, Speech, and Language Processing, Vol. 14, No. 5, September 2006, pp. 1557-1565.

Summary

Audio diarization is the process of annotating an input audio channel with information that attributes (possibly overlapping) temporal regions of signal energy to their specific sources. These sources can include particular speakers, music, background noise sources, and other signal source/channel characteristics. Diarization can be used for helping speech recognition, facilitating the searching and indexing of audio archives, and increasing the richness of automatic transcriptions, making them more readable. In this paper, we provide an overview of the approaches currently used in a key area of audio diarization, namely speaker diarization, and discuss their relative merits and limitations. Performances using the different techniques are compared within the framework of the speaker diarization task in the DARPA EARS Rich Transcription evaluations. We also look at how the techniques are being introduced into real broadcast news systems and their portability to other domains and tasks such as meetings and speaker verification.
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Summary

Audio diarization is the process of annotating an input audio channel with information that attributes (possibly overlapping) temporal regions of signal energy to their specific sources. These sources can include particular speakers, music, background noise sources, and other signal source/channel characteristics. Diarization can be used for helping speech recognition, facilitating...

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Toward an interagency language roundtable based assessment of speech-to-speech translation capabilitites

Published in:
AMTA 2006, 7th Biennial Conf. of the Association for Machine Translation in the Americas, 8-12 August 2006.

Summary

We present observations from three exercises designed to map the effective listening and speaking skills of an operator of a speech-to-speech translation system (S2S) to the Interagency Language Roundtable (ILR) scale. Such a mapping is nontrivial, but will be useful for government and military decision makers in managing expectations of S2S technology. We observed domain-dependent S2S capabilities in the ILR range of Level 0+ to Level 1, and interactive text-based machine translation in the Level 3 range.
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Summary

We present observations from three exercises designed to map the effective listening and speaking skills of an operator of a speech-to-speech translation system (S2S) to the Interagency Language Roundtable (ILR) scale. Such a mapping is nontrivial, but will be useful for government and military decision makers in managing expectations of...

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Experience using active and passive mapping for network situational awareness

Published in:
5th IEEE Int. Symp. on Network Computing and Applications NCA06, 24-26 July 2006, pp. 19-26.

Summary

Passive network mapping has often been proposed as an approach to maintain up-to-date information on networks between active scans. This paper presents a comparison of active and passive mapping on an operational network. On this network, active and passive tools found largely disjoint sets of services and the passive system took weeks to discover the last 15% of active services. Active and passive mapping tools provided different, not complimentary information. Deploying passive mapping on an enterprise network does not reduce the need for timely active scans due to non-overlapping coverage and potentially long discovery times.
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Summary

Passive network mapping has often been proposed as an approach to maintain up-to-date information on networks between active scans. This paper presents a comparison of active and passive mapping on an operational network. On this network, active and passive tools found largely disjoint sets of services and the passive system...

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Advanced language recognition using cepstra and phonotactics: MITLL system performance on the NIST 2005 Language Recognition Evaluation

Summary

This paper presents a description of the MIT Lincoln Laboratory submissions to the 2005 NIST Language Recognition Evaluation (LRE05). As was true in 2003, the 2005 submissions were combinations of core cepstral and phonotactic recognizers whose outputs were fused to generate final scores. For the 2005 evaluation, Lincoln Laboratory had five submissions built upon fused combinations of six core systems. Major improvements included the generation of phone streams using lattices, SVM-based language models using lattice-derived phonotactics, and binary tree language models. In addition, a development corpus was assembled that was designed to test robustness to unseen languages and sources. Language recognition trends based on NIST evaluations conducted since 1996 show a steady improvement in language recognition performance.
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Summary

This paper presents a description of the MIT Lincoln Laboratory submissions to the 2005 NIST Language Recognition Evaluation (LRE05). As was true in 2003, the 2005 submissions were combinations of core cepstral and phonotactic recognizers whose outputs were fused to generate final scores. For the 2005 evaluation, Lincoln Laboratory had...

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Compensating for mismatch in high-level speaker recognition

Published in:
2006 IEEE Odyssey, the Speaker and Language Recognition Workshop, 28-30 June 2006.

Summary

Speaker recognition using high-level features has been a successful area of exploration. Features obtained from many different levels phones, words, prosodic events, etc. are used to characterize the speaker. A good modeling technique for these features is the support vector machine (SVM). SVMs model the n-gram frequencies from speaker utterances in a high-dimensional SVM feature space and have shown excellent performance over a wide variety of high-level features. A complimentary method of recent exploration in SVM speaker recognition is the use of nuisance attribute projection (NAP). NAP removes directions from SVM feature space that are superfluous to the task of speaker recognition channel information, session variability, etc. In this paper, we consider the application of NAP to high-level speaker recognition. We describe the difficulties in applying this method and propose solutions. We also conduct experiments showing that NAP can reduce variability in SVM feature space leading to improved performance.
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Summary

Speaker recognition using high-level features has been a successful area of exploration. Features obtained from many different levels phones, words, prosodic events, etc. are used to characterize the speaker. A good modeling technique for these features is the support vector machine (SVM). SVMs model the n-gram frequencies from speaker utterances...

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Experiments with lattice-based PPRLM language identification

Summary

In this paper we describe experiments conducted during the development of a lattice-based PPRLM language identification system as part of the NIST 2005 language recognition evaluation campaign. In experiments following LRE05 the PPRLM-lattice sub-system presented here achieved a 30s/primary condition EER of 4.87%, making it the single best performing recognizer developed by the MIT-LL team. Details of implementation issues and experimental results are presented and interactions with backend score normalization are explored.
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Summary

In this paper we describe experiments conducted during the development of a lattice-based PPRLM language identification system as part of the NIST 2005 language recognition evaluation campaign. In experiments following LRE05 the PPRLM-lattice sub-system presented here achieved a 30s/primary condition EER of 4.87%, making it the single best performing recognizer...

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Understanding scores in forensic speaker recognition

Summary

Recent work in forensic speaker recognition has introduced many new scoring methodologies. First, confidence scores (posterior probabilities) have become a useful method of presenting results to an analyst. The introduction of an objective measure of confidence score quality, the normalized cross entropy, has resulted in a systematic manner of evaluating and designing these systems. A second scoring methodology that has become popular is support vector machines (SVMs) for high-level features. SVMs are accurate and produce excellent results across a wide variety of token types-words, phones, and prosodic features. In both cases, an analyst may be at a loss to explain the significance and meaning of the score produced by these methods. We tackle the problem of interpretation by exploring concepts from the statistical and pattern classification literature. In both cases, our preliminary results show interesting aspects of scores not obvious from viewing them "only as numbers."
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Summary

Recent work in forensic speaker recognition has introduced many new scoring methodologies. First, confidence scores (posterior probabilities) have become a useful method of presenting results to an analyst. The introduction of an objective measure of confidence score quality, the normalized cross entropy, has resulted in a systematic manner of evaluating...

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Nonlinear equalization for RF receivers

Published in:
Proc. Conf. on High Performance Computer Modernization Program, 26-29 June 2006, pp. 303-307.

Summary

This paper describes the need for High Performance Computing (HPC) to facilitate the development and implementation of a nonlinear equalizer that is capable of mitigating and/or eliminating nonlinear distortion to extend the dynamic range of radar front-end receivers decades beyond the analog state-of-the-art. The search space for the optimal nonlinear equalization (NLEQ) solution is computationally intractable using only a single desktop computer. However, we have been able to leverage a combination of an efficient greedy search with the high performance computing technologies of LLGrid and MatlabMPI to construct an NLEQ architecture that is capable of extending the dynamic range of Radar front-end receivers by over 25dB.
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Summary

This paper describes the need for High Performance Computing (HPC) to facilitate the development and implementation of a nonlinear equalizer that is capable of mitigating and/or eliminating nonlinear distortion to extend the dynamic range of radar front-end receivers decades beyond the analog state-of-the-art. The search space for the optimal nonlinear...

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