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Blind clustering of speech utterances based on speaker and language characteristics

November 30, 1998
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Conference Paper
Author:
Douglas A. Reynolds
…
Published in:
5th Int. Conf. Spoken Language Processing (ICSLP), 30 November - 4 December 1998.
Topic:
speaker recognition
R&D area:
R&D group:

Summary

Classical speaker and language recognition techniques can be applied to the classification of unknown utterances by computing the likelihoods of the utterances given a set of well trained target models. This paper addresses the problem of grouping unknown utterances when no information is available regarding the speaker or language classes or even the total number of classes. Approaches to blind message clustering are presented based on conventional hierarchical clustering techniques and an integrated cluster generation and selection method called the d* algorithm. Results are presented using message sets derived from the Switchboard and Callfriend corpora. Potential applications include automatic indexing of recorded speech corpora by speaker/language tags and automatic or semiautomatic selection of speaker specific speech utterances for speaker recognition adaptation.
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Summary

Classical speaker and language recognition techniques can be applied to the classification of unknown utterances by computing the likelihoods of the utterances given a set of well trained target models. This paper addresses the problem of grouping unknown utterances when no information is available regarding the speaker or language classes...

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Blind clustering of speech utterances based on speaker and language characteristics

Improving accent identification through knowledge of English syllable structure

November 30, 1998
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Conference Paper
Author:
Kay M. Berkling
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Published in:
5th Int. Conf. on Spoken Language Processing, ICSLP, 30 November - 4 December 1998.
Topic:
language recognition
R&D area:
R&D group:

Summary

This paper studies the structure of foreign-accented read English speech. A system for accent identification is constructed by combining linguistic theory with statistical analysis. Results demonstrate that the linguistic theory is reflected in real speech data and its application improves accent identification. The work discussed here combines and applies previous research in language identification based on phonemic features [1] with the analysis of the structure and function of the English language [2]. Working with phonemically hand-labelled data in three accented speaker groups of Australian English (Vietnamese, Lebanese, and native speakers), we show that accents of foreign speakers can be predicted and manifest themselves differently as a function of their position within the syllable. When applying this knowledge, English vs. Vietnamese accent identification improves from 86% to 93% (English vs. Lebanese improves from 78% to 84%). The described algorithm is also applied to automatically aligned phonemes.
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Summary

This paper studies the structure of foreign-accented read English speech. A system for accent identification is constructed by combining linguistic theory with statistical analysis. Results demonstrate that the linguistic theory is reflected in real speech data and its application improves accent identification. The work discussed here combines and applies previous...

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Improving accent identification through knowledge of English syllable structure

Airbus 320 performance during ATC-directed breakouts on final approach

November 20, 1998
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Project Report
Author:
Katherine de M. Hollister
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Published in:
MIT Lincoln Laboratory Report ATC-265
Topic:
air traffic control
R&D area:

Summary

An evaluation of Airbus 320 (A320) performance during ATC-directed breakouts was conducted in a two-part study during 1995. Phase 1 tested the combined effect of proposed ATC phraseology, pilot situational awareness training, and an A320-specific breakout procedure on performance. Pilot training included a briefing and viewing a videotape, but no simulator practice. Turn performance statistics from the Precision Runway Monitor Demonstration Program were used as the test criteria. Pilot preferences regarding procedures and the training material were also elicited. Three conclusions were: (1) breakout performance given the tested combination of pilot training and proposed ATC phraseology did meet the test criteria; (2) breakout performance given existing procedures did not meet the test criteria; and (3) the tested breakout procedure should be refined because it conflicted with other cockpit procedures and increased the transition time to a positive climb rate. Based on the results of this study, it is recommended that a combination of pilot situational awareness training, A320 breakout procedure, and modified ATC breakout phraseology equivalent to that tested in Phase 2 be employed for simultaneous parallel approach operations in instrument meteorological conditions.
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Summary

An evaluation of Airbus 320 (A320) performance during ATC-directed breakouts was conducted in a two-part study during 1995. Phase 1 tested the combined effect of proposed ATC phraseology, pilot situational awareness training, and an A320-specific breakout procedure on performance. Pilot training included a briefing and viewing a videotape, but no...

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Airbus 320 performance during ATC-directed breakouts on final approach

Sheep, goats, lambs and wolves: a statistical analysis of speaker performance in the NIST 1998 speaker recognition evaluation

November 1, 1998
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Conference Paper
Author:
George R. Doddington
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Published in:
NIST 1998 Speaker Recognition Evaluation, November 1998.
Topic:
speaker recognition
R&D area:
R&D group:

Summary

Performance variability in speech and speaker recognition systems can be attributed to many factors. One major factor, which is often acknowledged but seldom analyzed, is inherent differences in the recognizability of different speakers. In speaker recognition systems such differences are characterized by the use of animal names for different types of speakers, including sheep, goats, lambs and wolves, depending on their behavior with respect to automatic recognition systems. In this paper we propose statistical tests for the existence of these animals and apply these tests to hunt for such animals using results from the 1998 NIST speaker recognition evaluation.
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Summary

Performance variability in speech and speaker recognition systems can be attributed to many factors. One major factor, which is often acknowledged but seldom analyzed, is inherent differences in the recognizability of different speakers. In speaker recognition systems such differences are characterized by the use of animal names for different types...

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Sheep, goats, lambs and wolves: a statistical analysis of speaker performance in the NIST 1998 speaker recognition evaluation

A dual-band circularly polarized aperture-coupled stacked microstrip antenna for global positioning satellite

November 1, 1998
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Journal Article
Author:
D. M. Pozar
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Published in:
IEEE Trans. Antennas Propag., Vol. 45, No. 11, November 1997, pp. 1618-25.
Topic:
antennas
R&D area:
R&D group:

Summary

This paper describes the design and testing of an aperture-coupled circularly polarized antenna for global positioning satellite (GPS) applications. The antenna operates at both the L1 and L2 frequencies of 1575 and 1227 MHz, which is required for differential GPS systems in order to provide maximum positioning accuracy. Electrical performance, low-profile, and cost were equally important requirements for this antenna. The design procedure is discussed, and measured results are presented. Results from a manufacturing sensitivity analysis are also included.
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Summary

This paper describes the design and testing of an aperture-coupled circularly polarized antenna for global positioning satellite (GPS) applications. The antenna operates at both the L1 and L2 frequencies of 1575 and 1227 MHz, which is required for differential GPS systems in order to provide maximum positioning accuracy. Electrical performance...

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A dual-band circularly polarized aperture-coupled stacked microstrip antenna for global positioning satellite

Techniques for improved reception of 1090 MHz ADS-B signals

October 31, 1998
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Conference Paper
Author:
William H. Harman III
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Published in:
17th DASC: Proc. of the 17th. Digital Avionics Systems Conf., 31 October - 7 November 1998, Vol. 2, pp. G25-1 - G25-9.
Topic:
surveillance
R&D area:
R&D group:

Summary

The recent development of ADS-B (Automatic Dependent Surveillance-Broadcast) is based on the use of the Mode S transponders now carried by all air carrier and commuter aircraft. ADS-B aircraft broadcast aircraft positions, identity, and other information via semi-random Mode S transponder squitters. Other aircraft or ground facilities receive the squitters and the associated position and status. Squitter reception includes the detection of the Mode S 1090 MHz waveform preamble, declaration of the bit and confidence values, error detection, and (if necessary) error correction. The current techniques for squitter reception are based upon methods developed for use in Mode S narrow-beam interrogators and for ACAS. In both of these applications, the rate of Mode NC fruit that is stronger than the Mode S waveform is relatively low, nominally less than 4,000 fruit per second. Extended squitter applications now include long range (up to 100 nmi) air-air surveillance in support of free flight. This type of surveillance is sometimes referred to as Cockpit Display of Traffic Information (CDTI). In high density environments, it is possible to operate with fruit rates of 40,000 fruit per second and higher. Operation of extended squitter in very high ModeNC fruit environments has led to the need to re-evaluate squitter reception techniques to determine if improved performance is achievable. The purpose of this paper is to provide a summary of work in progress to investigate improved squitter reception techniques. Elements of improved squitter reception being investigated include (1) the use of amplitude to improve bit and confidence declaration accuracy, (2) more capable error correction algorithms, and (3) more selective preamble detection approaches.
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Summary

The recent development of ADS-B (Automatic Dependent Surveillance-Broadcast) is based on the use of the Mode S transponders now carried by all air carrier and commuter aircraft. ADS-B aircraft broadcast aircraft positions, identity, and other information via semi-random Mode S transponder squitters. Other aircraft or ground facilities receive the squitters...

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Techniques for improved reception of 1090 MHz ADS-B signals

Vulnerabilities of reliable multicast protocols

October 21, 1998
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Conference Paper
Author:
Thomas M. Parks
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Published in:
IEEE MILCOM '98, Vol. 3, 21 October 1998, pp. 934-938.
Topic:
cryptography
R&D area:
R&D group:

Summary

We examine vulnerabilities of several reliable multicast protocols. The various mechanisms employed by these protocols to provide reliability can present vulnerabilities. We show how some of these vulnerabilities can be exploited in denial-of-service attacks, and discuss potential mechanisms for withstanding such attacks.
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Summary

We examine vulnerabilities of several reliable multicast protocols. The various mechanisms employed by these protocols to provide reliability can present vulnerabilities. We show how some of these vulnerabilities can be exploited in denial-of-service attacks, and discuss potential mechanisms for withstanding such attacks.

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Vulnerabilities of reliable multicast protocols

AM-FM separation using shunting neural networks

October 6, 1998
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Conference Paper
Author:
Robert A. Baxter
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Published in:
Proc. of the IEEE-SP Int. Symp. on Time-Frequency and Time-Scale Analysis, 6-9 October 1998, pp. 553-556.
Topic:
signal processing
R&D area:
R&D group:

Summary

We describe an approach to estimating the amplitude-modulated (AM) and frequency-modulated (FM) components of a signal. Any signal can be written as the product of an AM component and an FM component. There have been several approaches to solving the AM-FM estimation problem described in the literature. Popular methods include the use of time-frequency analysis, the Hilbert transform, and the Teager energy operator. We focus on an approach based on FM-to-AM transduction that is motivated by auditory physiology. We show that the transduction approach can be realized as a bank of bandpass filters followed by envelope detectors and shunting neural networks, and the resulting dynamical system is capable of robust AM-FM estimation in noisy environments and over a broad range of filter bandwidths and locations. Our model is consistent with recent psychophysical experiments that indicate AM and FM components of acoustic signals may be transformed into a common neural code in the brain stem via FM-to-AM transduction. Applications of our model include signal recognition and multi-component decomposition.
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Summary

We describe an approach to estimating the amplitude-modulated (AM) and frequency-modulated (FM) components of a signal. Any signal can be written as the product of an AM component and an FM component. There have been several approaches to solving the AM-FM estimation problem described in the literature. Popular methods include...

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AM-FM separation using shunting neural networks

1.5-um Tapered-Gain-Region Lasers with High-CW Output Powers

October 1, 1998
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Journal Article
Author:
Joseph P. Donnelly
…
Published in:
IEEE Photonics Technol. Lett., Vol. 10, No. 10, October 1998, pp. 1377-1379.
Topic:
optics
R&D area:
R&D group:

Summary

High-power diode lasers consisting of a ridge-waveguide section coupled to a tapered region have been fabricated in 1.5um InGaAsP-InP multiple-quantum-well material. Self-focusing at high current densities and high-intensity input into the taper section has been identified as a fundamental problem in these devices that has to be dealt with. To date, continuous-wave output powers>1 W with=80% of the power in the near-diffraction-limited central lobe of the far field have been obtained through a judicious choice of device parameters.
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Summary

High-power diode lasers consisting of a ridge-waveguide section coupled to a tapered region have been fabricated in 1.5um InGaAsP-InP multiple-quantum-well material. Self-focusing at high current densities and high-intensity input into the taper section has been identified as a fundamental problem in these devices that has to be dealt with. To...

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1.5-um Tapered-Gain-Region Lasers with High-CW Output Powers

Comparisons between total lightning data, mesocyclone strength, and storm damage associated with the Florida tornado outbreak of February 23 1998

September 14, 1998
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Conference Paper
Author:
Stephen Hodanish
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Published in:
19th Conf. on Severe Local Storms, 14-18 September 1998, pp. 681-684.
Topic:
weather
R&D area:
R&D group:

Summary

During the late evening and early morning hours of February 22/23 1998, the worst tornado outbreak in recorded history occurred over the peninsula of central Florida. Analysis of KMLB Doppler radar data indicated at least 9 supercells developed over the region, with 4 of the supercells producing tornadoes. These 4 tornadic supercells produced a total of 7 tornadoes, some of them on the ground for tens of miles (Fig. 1.). A total of 42 fatalities were reported with over 260 injured. Monetary losses totaled over 100 million dollars. During this severe weather outbreak, National Weather Service Melbourne, in collaboration with the National Aeronautics and Space Administration and the Massachusetts Institute of Technology, was collecting data from a unique lightning observing system called Lightning Imaging Sensor Data Applications Display (LISDAD). This system has the capability to combine radar reflectivity data collected from the KMLB WSR-88D, cloud to ground data collected from the National Lightning Detection Network, and total lightning data collected from NASA's Lightning Detection And Ranging (LDAR) system. The object of this study is to compare total lightning data collected from the LISDAD system to mesocyclone strength as observed from the KMLB WSR-88D. These data will then be compared to the times of tornadic winds.
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Summary

During the late evening and early morning hours of February 22/23 1998, the worst tornado outbreak in recorded history occurred over the peninsula of central Florida. Analysis of KMLB Doppler radar data indicated at least 9 supercells developed over the region, with 4 of the supercells producing tornadoes. These 4...

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Comparisons between total lightning data, mesocyclone strength, and storm damage associated with the Florida tornado outbreak of February 23 1998
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