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LLiST - a new star tracker camera for tip-tilt correction at IOTA

June 21, 2004
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Conference Paper
Author:
P. A. Schuller
…
Published in:
2004 SPIE Conf. on Astronomical Telescopes and Instrumentation, 21-26 June 2004.
Topic:
optics
R&D area:
R&D group:

Summary

The tip-tilt correction system at the Infrared Optical Telescope Array (IOTA) has been upgraded with a new star tracker camera. The camera features a backside-illuminated CCD chip offering doubled overall quantum efficiency and a four times higher system gain compared to the previous system. Tests carried out to characterize the new system showed a higher system gain with a lower read-out noise electron level. Shorter read-out cycle times now allow to compensate tip-tilt fluctuations so that their error imposed on visibility measurements becomes comparable to, and even smaller than, that of higher-order aberrations.
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Summary

The tip-tilt correction system at the Infrared Optical Telescope Array (IOTA) has been upgraded with a new star tracker camera. The camera features a backside-illuminated CCD chip offering doubled overall quantum efficiency and a four times higher system gain compared to the previous system. Tests carried out to characterize the...

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LLiST - a new star tracker camera for tip-tilt correction at IOTA

The orthogonal-transfer array: a new CCD architecture for astronomy

June 21, 2004
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Conference Paper
Author:
Barry E. Burke
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Published in:
SPIE Vol. 5499, Optical and Infrared Detectors for Astronomy, 21 June 2004, pp. 185-192.
Topic:
optics
R&D area:
R&D group:

Summary

The orthogonal-transfer array (OTA) is a new CCD architecture designed to provide wide-field tip-tilt correction of astronomical images. The device consists of an 8..8 array of small (~500x500 pixels) orthogonal-transfer CCDs (OTCCD) with independent addressing and readout of each OTCCD. This approach enables an optimum tip-tilt correction to be applied independently to each OTCCD across the focal plane. The first design of this device has been carried out at MIT Lincoln Laboratory in support of the Pan-STARRS program with a collaborative parallel effort at Semiconductor Technology Associates (STA) for the WIYN Observatory. The two versions of this device are functionally compatible and share a common pinout and package. The first wafer lots are complete at Lincoln and at Dalsa and are undergoing wafer probing.
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Summary

The orthogonal-transfer array (OTA) is a new CCD architecture designed to provide wide-field tip-tilt correction of astronomical images. The device consists of an 8..8 array of small (~500x500 pixels) orthogonal-transfer CCDs (OTCCD) with independent addressing and readout of each OTCCD. This approach enables an optimum tip-tilt correction to be applied...

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The orthogonal-transfer array: a new CCD architecture for astronomy

A high-power MEMS electric induction motor

June 1, 2004
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Journal Article
Author:
C. Livermore
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Published in:
J. Microelectromech. Syst., Vol. 13, No. 3, June 2004, pp. 465-471.
Topic:
microelectronics
R&D area:
R&D group:

Summary

An electric induction micromotor with a 4-mm-diameter rotor was designed and built for high-power operation. Operated at partial actuating voltage, the motor has demonstrated an air gap power in excess of 20 mWand torque of 3 5 Nmat speeds in excess of 55 000 rpm. Operation at higher power and speed was limited by bearing stability at higher rotational speeds. The device builds on an earlier micromotor demonstrated by Frechette et al. The high power of the present motor is enabled by its low-loss, high-voltage electric stator, which also offers improved efficiency. The development of this electromechanical device is an important enabling step not only for watt-scale micromotors, but also for the development of microelectric generators. This paper presents the motorαs design, the fabrication process that was created to meet its stringent design requirements, and its performance to date.
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Summary

An electric induction micromotor with a 4-mm-diameter rotor was designed and built for high-power operation. Operated at partial actuating voltage, the motor has demonstrated an air gap power in excess of 20 mWand torque of 3 5 Nmat speeds in excess of 55 000 rpm. Operation at higher power and...

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A high-power MEMS electric induction motor

Dynamic response of an electronically shuttered CCD imager

June 1, 2004
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Journal Article
Author:
Dennis D. Rathman
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Published in:
IEEE. Trans. Electron Devices, Vol. 51, No. 6, June 2004, pp. 864-869.
Topic:
sensors
R&D area:
R&D group:

Summary

The dynamic response of an electronically shuttered charge-coupled device (CCD) imager to nanosecond voltage pulses has been investigated. Measurements show that the shutter can be dynamically opened and closed in nanosecond times. For the shutter opening, simulations indicate that the collection of photoelectrons occurs in times much shorter than that needed to form the steady-state depletion region under the CCD well. In addition, the shutter closing occurs faster than the reconstitution of the p-buried (shutter) layer. Simulations further indicate that electric fields created in the neutral substrate by the shutter clocks enable photogenerated charge collection/rejection on nanosecond time scales despite the fact that the depletion-region formation and collapse take much longer times.
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Summary

The dynamic response of an electronically shuttered charge-coupled device (CCD) imager to nanosecond voltage pulses has been investigated. Measurements show that the shutter can be dynamically opened and closed in nanosecond times. For the shutter opening, simulations indicate that the collection of photoelectrons occurs in times much shorter than that...

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Dynamic response of an electronically shuttered CCD imager

Channel compensation for SVM speaker recognition

May 31, 2004
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Conference Paper
Author:
Alex Solomonoff
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Published in:
Odyssey, The Speaker and Language Recognition Workshop, 31 May - 3 June 2004.
Topic:
speaker recognition
R&D area:
R&D group:

Summary

One of the major remaining challenges to improving accuracy in state-of-the-art speaker recognition algorithms is reducing the impact of channel and handset variations on system performance. For Gaussian Mixture Model based speaker recognition systems, a variety of channel-adaptation techniques are known and available for adapting models between different channel conditions, but for the much more recent Support Vector Machine (SVM) based approaches to this problem, much less is known about the best way to handle this issue. In this paper we explore techniques that are specific to the SVM framework in order to derive fully non-linear channel compensations. The result is a system that is less sensitive to specific kinds of labeled channel variations observed in training.
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Summary

One of the major remaining challenges to improving accuracy in state-of-the-art speaker recognition algorithms is reducing the impact of channel and handset variations on system performance. For Gaussian Mixture Model based speaker recognition systems, a variety of channel-adaptation techniques are known and available for adapting models between different channel conditions...

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Channel compensation for SVM speaker recognition

Fusing discriminative and generative methods for speaker recognition: experiments on switchboard and NFI/TNO field data

May 31, 2004
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Conference Paper
Author:
William M. Campbell
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Published in:
ODYSSEY 2004, Speaker and Language Recognition Workshop, 31 May - 3 June 2004.
Topic:
speaker recognition
R&D area:
R&D group:

Summary

Discriminatively trained support vector machines have recently been introduced as a novel approach to speaker recognition. Support vector machines (SVMs) have a distinctly different modeling strategy in the speaker recognition problem. The standard Gaussian mixture model (GMM) approach focuses on modeling the probability density of the speaker and the background (a generative approach). In contrast, the SVM models the boundary between the classes. Another interesting aspect of the SVM is that it does not directly produce probabilistic scores. This poses a challenge for combining results with a GMM. We therefore propose strategies for fusing the two approaches. We show that the SVM and GMM are complementary technologies. Recent evaluations by NIST (telephone data) and NFI/TNO (forensic data) give a unique opportunity to test the robustness and viability of fusing GMM and SVM methods. We show that fusion produces a system which can have relative error rates 23% lower than individual systems.
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Summary

Discriminatively trained support vector machines have recently been introduced as a novel approach to speaker recognition. Support vector machines (SVMs) have a distinctly different modeling strategy in the speaker recognition problem. The standard Gaussian mixture model (GMM) approach focuses on modeling the probability density of the speaker and the background...

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Fusing discriminative and generative methods for speaker recognition: experiments on switchboard and NFI/TNO field data

Dialect identification using Gaussian mixture models

May 31, 2004
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Conference Paper
Author:
Pedro A. Torres-Carrasquillo
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Published in:
ODYSSEY 2004, Speaker and Language Recognition Workshop, 31 May - 3 June 2004.
Topic:
language recognition
R&D area:
R&D group:

Summary

Recent results in the area of language identification have shown a significant improvement over previous systems. In this paper, we evaluate the related problem of dialect identification using one of the techniques recently developed for language identification, the Gaussian mixture models with shifted-delta-cepstral features. The system shown is developed using the same methodology followed for the language identification case. Results show that the use of the GMM techniques yields an average of 30% equal error rate for the dialects in the Miami corpus and about 13% equal error rate for the dialects in the CallFriend corpus.
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Summary

Recent results in the area of language identification have shown a significant improvement over previous systems. In this paper, we evaluate the related problem of dialect identification using one of the techniques recently developed for language identification, the Gaussian mixture models with shifted-delta-cepstral features. The system shown is developed using...

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Dialect identification using Gaussian mixture models

Speaker diarisation for broadcast news

May 31, 2004
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Conference Paper
Author:
Sue E. Tranter
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Published in:
Odyssey 2004, 31 May - 4 June 2004.
Topic:
speaker recognition
R&D area:
R&D group:

Summary

It is often important to be able to automatically label 'who spoke when' during some audio data. This paper describes two systems for audio segmentation developed at CUED and MIT-LL and evaluates their performance using the speaker diarisation score defined in the 2003 Rich Transcription Evaluation. A new clustering procedure and BIC-based stopping criterion for the CUED system is introduced which improves both performance and robustness to changes in segmentation. Finally a hybrid 'Plug and Play' system is built which combines different parts of the CUED and MIT-LL systems to produce a single system which outperforms both the individual systems.
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Summary

It is often important to be able to automatically label 'who spoke when' during some audio data. This paper describes two systems for audio segmentation developed at CUED and MIT-LL and evaluates their performance using the speaker diarisation score defined in the 2003 Rich Transcription Evaluation. A new clustering procedure...

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Speaker diarisation for broadcast news

Language recognition with support vector machines

May 31, 2004
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Conference Paper
Author:
William M. Campbell
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Published in:
ODYSSEY 2004, Speaker and Language Recognition Workshop, 31 May - 3 June 2004.
Topic:
language recognition
R&D area:
R&D group:

Summary

Support vector machines (SVMs) have become a popular tool for discriminative classification. Powerful theoretical and computational tools for support vector machines have enabled significant improvements in pattern classification in several areas. An exciting area of recent application of support vector machines is in speech processing. A key aspect of applying SVMs to speech is to provide a SVM kernel which compares sequences of feature vectors--a sequence kernel. We propose the use of sequence kernels for language recognition. We apply our methods to the NIST 2003 language evaluation task. Results demonstrate the potential of the new SVM methods.
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Summary

Support vector machines (SVMs) have become a popular tool for discriminative classification. Powerful theoretical and computational tools for support vector machines have enabled significant improvements in pattern classification in several areas. An exciting area of recent application of support vector machines is in speech processing. A key aspect of applying...

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Language recognition with support vector machines

The MMSR bilingual and crosschannel corpora for speaker recognition research and evaluation

May 31, 2004
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Conference Paper
Author:
Joseph P. Campbell Jr
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Published in:
ODYSSEY 2004, Speaker and Language Recognition Workshop, 31 May - 3 June 2004.
Topic:
human language technology
R&D area:
R&D group:

Summary

We describe efforts to create corpora to support and evaluate systems that meet the challenge of speaker recognition in the face of both channel and language variation. In addition to addressing ongoing evaluation of speaker recognition systems, these corpora are aimed at the bilingual and crosschannel dimensions. We report on specific data collection efforts at the Linguistic Data Consortium, the 2004 speaker recognition evaluation program organized by the National Institute of Standards and Technology (NIST), and the research ongoing at the US Federal Bureau of Investigation and MIT Lincoln Laboratory. We cover the design and requirements, the collections and evaluation integrating discussions of the data preparation, research, technology development and evaluation on a grand scale.
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Summary

We describe efforts to create corpora to support and evaluate systems that meet the challenge of speaker recognition in the face of both channel and language variation. In addition to addressing ongoing evaluation of speaker recognition systems, these corpora are aimed at the bilingual and crosschannel dimensions. We report on...

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The MMSR bilingual and crosschannel corpora for speaker recognition research and evaluation
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