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Model estimates of traffic reduction in storm impacted en route airspace

September 18, 2007
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Conference Paper
Author:
Brian D. Martin
Published in:
7th AIAA Aviation Technology, Integration, and Operations (ATIO) Conf., 18-20 September 2007.
Topic:
air traffic control
R&D area:
R&D group:

Summary

An understanding of convective weather impacts on en route airspace capacity is a first step toward development of predictive tools to support both tactical and strategic routing decisions in storm-impacted airspace. This study presents a model for traffic reductions in en route sectors that result from convective weather impacts. A model to predict the impact of convective weather on en route traffic, Traffic Normalized Fractional Route Availability (TNFRA), combines Weather Avoidance Fields (WAF) from the Convective Weather Avoidance Model (CWAM) with a model for route usage in air traffic control (ATC) sectors. The model estimates the number of flights that will be able to pass through convective weather in a given sector. Results show that TNFRA provides a relatively unbiased estimate of sector traffic when compared to actual operations during high impact - convective weather events.
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Summary

An understanding of convective weather impacts on en route airspace capacity is a first step toward development of predictive tools to support both tactical and strategic routing decisions in storm-impacted airspace. This study presents a model for traffic reductions in en route sectors that result from convective weather impacts. A...

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Model estimates of traffic reduction in storm impacted en route airspace

Evaluation of potential NEXRAD dual polarization products

September 4, 2007
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Project Report
Author:
David J. Smalley
Published in:
MIT Lincoln Laboratory Report ATC-336
Topic:
signal processing
R&D area:
R&D group:

Summary

The NEXRAD program will begin fielding a dual polarization capability in 2009. Three additional base data parameters and two additional derived parameters from the dual polarization capability will be produced to complement the traditional three radar moments. The initial use of the added data is to provide a dual-polarization-based quantitative precipitation estimate (QPE) algorithm. Other NEXRAD algorithms will have access to the new dual polarization parameters as well as the derived products. The National Severe Storms Laboratory coordinated a dual polarization product evaluation to solicit NEXRAD agency participant feedback regarding potential dual polarization products. The evaluation consisted of analyzing dual polarization data from seven weather cases. MIT Lincoln Laboratory participated in the evaluation. The evaluation opportunity was used to have early access to prototypical dual polarization data to consider the potential benefit to FAA weather systems. This report introduces the new dual polarization pararmeters, presents some of the relevant weather cases, and provides recommendations regarding use of the dual polarization parameters.
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Summary

The NEXRAD program will begin fielding a dual polarization capability in 2009. Three additional base data parameters and two additional derived parameters from the dual polarization capability will be produced to complement the traditional three radar moments. The initial use of the added data is to provide a dual-polarization-based quantitative...

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Evaluation of potential NEXRAD dual polarization products

Classification methods for speaker recognition

September 1, 2007
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Book Chapter
Author:
Douglas E. Sturim
…
Published in:
Chapter in Springer Lecture Notes in Artificial Intelligence, 2007.
Topic:
speaker recognition
R&D area:
R&D group:

Summary

Automatic speaker recognition systems have a foundation built on ideas and techniques from the areas of speech science for speaker characterization, pattern recognition and engineering. In this chapter we provide an overview of the features, models, and classifiers derived from these areas that are the basis for modern automatic speaker recognition systems. We describe the components of state-of-the-art automatic speaker recognition systems, discuss application considerations and provide a brief survey of accuracy for different tasks.
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Summary

Automatic speaker recognition systems have a foundation built on ideas and techniques from the areas of speech science for speaker characterization, pattern recognition and engineering. In this chapter we provide an overview of the features, models, and classifiers derived from these areas that are the basis for modern automatic speaker...

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Classification methods for speaker recognition

Speaker verification using support vector machines and high-level features

September 1, 2007
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Journal Article
Author:
William M. Campbell
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Published in:
IEEE Trans. on Audio, Speech, and Language Process., Vol. 15, No. 7, September 2007, pp. 2085-2094.
Topic:
language recognition
R&D area:
R&D group:

Summary

High-level characteristics such as word usage, pronunciation, phonotactics, prosody, etc., have seen a resurgence for automatic speaker recognition over the last several years. With the availability of many conversation sides per speaker in current corpora, high-level systems now have the amount of data needed to sufficiently characterize a speaker. Although a significant amount of work has been done in finding novel high-level features, less work has been done on modeling these features. We describe a method of speaker modeling based upon support vector machines. Current high-level feature extraction produces sequences or lattices of tokens for a given conversation side. These sequences can be converted to counts and then frequencies of -gram for a given conversation side. We use support vector machine modeling of these n-gram frequencies for speaker verification. We derive a new kernel based upon linearizing a log likelihood ratio scoring system. Generalizations of this method are shown to produce excellent results on a variety of high-level features. We demonstrate that our methods produce results significantly better than standard log-likelihood ratio modeling. We also demonstrate that our system can perform well in conjunction with standard cesptral speaker recognition systems.
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Summary

High-level characteristics such as word usage, pronunciation, phonotactics, prosody, etc., have seen a resurgence for automatic speaker recognition over the last several years. With the availability of many conversation sides per speaker in current corpora, high-level systems now have the amount of data needed to sufficiently characterize a speaker. Although...

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Speaker verification using support vector machines and high-level features

pMATLAB parallel MATLAB library

September 1, 2007
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Journal Article
Author:
Nadya T. Bliss
…
Published in:
Int. J. High Perform. Comp. Appl., Vol. 21, No. 3, Fall 2007, pp. 336-359.
Topic:
high performance computing
R&D area:
R&D group:

Summary

MATLAB has emerged as one of the languages most commonly used by scientists and engineers for technical computing, with approximately one million users worldwide. The primary benefits of MATLAB are reduced code development time via high levels of abstractions (e.g. first class multi-dimensional arrays and thousands of built in functions), interpretive, interactive programming, and powerful mathematical graphics. The compute intensive nature of technical computing means that many MATLAB users have codes that can significantly benefit from the increased performance offered by parallel computing. pMatlab provides this capability by implementing parallel global array semantics using standard operator overloading techniques. The core data structure in pMatlab is a distributed numerical array whose distribution onto multiple processors is specified with a "map" construct. Communication operations between distributed arrays are abstracted away from the user and pMatlab transparently supports redistribution between any block-cyclic-overlapped distributions up to four dimensions. pMatlab is built on top of the MatlabMPI communication library and runs on any combination of heterogeneous systems that support MATLAB, which includes Windows, Linux, MacOS X, and SunOS. This paper describes the overall design and architecture of the pMatlab implementation. Performance is validated by implementing the HPC Challenge benchmark suite and comparing pMatlab performance with the equivalent C+MPI codes. These results indicate that pMatlab can often achieve comparable performance to C+MPI, usually at one tenth the code size. Finally, we present implementation data collected from a sample of real pMatlab applications drawn from the approximately one hundred users at MIT Lincoln Laboratory. These data indicate that users are typically able to go from a serial code to an efficient pMatlab code in about 3 hours while changing less than 1% of their code.
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Summary

MATLAB has emerged as one of the languages most commonly used by scientists and engineers for technical computing, with approximately one million users worldwide. The primary benefits of MATLAB are reduced code development time via high levels of abstractions (e.g. first class multi-dimensional arrays and thousands of built in functions)...

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pMATLAB parallel MATLAB library

Back-illuminated three-dimensionally integrated CMOS image sensors for scientific applications

August 27, 2007
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Conference Paper
Author:
Vyshnavi Suntharalingam
…
Published in:
SPIE Vol. 6690, Focal Plane Arrays for Space Telescopes III, 27-28 August 2007, 669009.
Topic:
sensors
R&D area:
R&D group:

Summary

SOI-based active pixel image sensors have been built in both monolithic and vertically interconnected pixel technologies. The latter easily supports the inclusion of more complex pixel circuitry without compromising pixel fill factor. A wafer-scale back-illumination process is used to achieve 100% fill factor photodiodes. Results from 256 x 256 and 1024 x 1024 pixel arrays are presented, with discussion of dark current improvement in the differing technologies.
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Summary

SOI-based active pixel image sensors have been built in both monolithic and vertically interconnected pixel technologies. The latter easily supports the inclusion of more complex pixel circuitry without compromising pixel fill factor. A wafer-scale back-illumination process is used to achieve 100% fill factor photodiodes. Results from 256 x 256 and...

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Back-illuminated three-dimensionally integrated CMOS image sensors for scientific applications

Construction of a phonotactic dialect corpus using semiautomatic annotation

August 27, 2007
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Conference Paper
Author:
Reva Schwartz
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Published in:
INTERSPEECH 2007, 27-31 August 2007, pp. 942-945.
Topic:
human language technology
R&D area:
R&D group:

Summary

In this paper, we discuss rapid, semiautomatic annotation techniques of detailed phonological phenomena for large corpora. We describe the use of these techniques for the development of a corpus of American English dialects. The resulting annotations and corpora will support both large-scale linguistic dialect analysis and automatic dialect identification. We delineate the semiautomatic annotation process that we are currently employing and, a set of experiments we ran to validate this process. From these experiments, we learned that the use of ASR techniques could significantly increase the throughput and consistency of human annotators.
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Summary

In this paper, we discuss rapid, semiautomatic annotation techniques of detailed phonological phenomena for large corpora. We describe the use of these techniques for the development of a corpus of American English dialects. The resulting annotations and corpora will support both large-scale linguistic dialect analysis and automatic dialect identification. We...

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Construction of a phonotactic dialect corpus using semiautomatic annotation

A comparison of speaker clustering and speech recognition techniques for air situational awareness

August 27, 2007
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Conference Paper
Author:
Wade Shen
…
Published in:
INTERSPEECH 2007, 27-31 August 2007, pp. 2421-2424.
Topic:
speaker recognition
R&D area:
R&D group:

Summary

In this paper we compare speaker clustering and speech recognition techniques to the problem of understanding patterns of air traffic control communications. For a given radio transmission, our goal is to identify the talker and to whom he/she is speaking. This information, in combination with knowledge of the roles (i.e. takeoff, approach, hand-off, taxi, etc.) of different radio frequencies within an air traffic control region could allow tracking of pilots through various stages of flight, thus providing the potential to monitor the airspace in great detail. Both techniques must contend with degraded audio channels and significant non-native accents. We report results from experiments using the nn-MATC database showing 9.3% and 32.6% clustering error for speaker clustering and ASR methods respectively.
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Summary

In this paper we compare speaker clustering and speech recognition techniques to the problem of understanding patterns of air traffic control communications. For a given radio transmission, our goal is to identify the talker and to whom he/she is speaking. This information, in combination with knowledge of the roles (i.e...

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A comparison of speaker clustering and speech recognition techniques for air situational awareness

A new kernel for SVM MLLR based speaker recognition

August 27, 2007
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Conference Paper
Author:
Zahi N. Karam
…
Published in:
INTERSPEECH, 27-31 August 2007.
Topic:
speaker recognition
R&D area:
R&D group:

Summary

Speaker recognition using support vector machines (SVMs) with features derived from generative models has been shown to perform well. Typically, a universal background model (UBM) is adapted to each utterance yielding a set of features that are used in an SVM. We consider the case where the UBM is a Gaussian mixture model (GMM), and maximum likelihood linear regression (MLLR) adaptation is used to adapt the means of the UBM. We examine two possible SVM feature expansions that arise in this context: the first, a GMM supervector is constructed by stacking the means of the adapted GMM, and the second consists of the elements of the MLLR transform. We examine several kernels associated with these expansions. We show that both expansions are equivalent given an appropriate choice of kernels. Experiments performed on the NIST SRE 2006 corpus clearly highlight that our choice of kernels, which are motivated by distance metrics between GMMs, outperform ad-hoc ones. We also apply SVM nuisance attribute projection (NAP) to the kernels as a form of channel compensation and show that, with a proper choice of kernel, we achieve results comparable to existing SVM based recognizers.
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Summary

Speaker recognition using support vector machines (SVMs) with features derived from generative models has been shown to perform well. Typically, a universal background model (UBM) is adapted to each utterance yielding a set of features that are used in an SVM. We consider the case where the UBM is a...

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A new kernel for SVM MLLR based speaker recognition

Improving phonotactic language recognition with acoustic adaptation

August 27, 2007
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Conference Paper
Author:
Wade Shen
…
Published in:
INTERSPEECH 2007, 27-31 August 2007, pp. 358-361.
Topic:
language recognition
R&D area:
R&D group:

Summary

In recent evaluations of automatic language recognition systems, phonotactic approaches have proven highly effective. However, as most of these systems rely on underlying ASR techniques to derive a phonetic tokenization, these techniques are potentially susceptible to acoustic variability from non-language sources (i.e. gender, speaker, channel, etc.). In this paper we apply techniques from ASR research to normalize and adapt HMM-based phonetic models to improve phonotactic language recognition performance. Experiments we conducted with these techniques show an EER reduction of 29% over traditional PRLM-based approaches.
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Summary

In recent evaluations of automatic language recognition systems, phonotactic approaches have proven highly effective. However, as most of these systems rely on underlying ASR techniques to derive a phonetic tokenization, these techniques are potentially susceptible to acoustic variability from non-language sources (i.e. gender, speaker, channel, etc.). In this paper we...

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Improving phonotactic language recognition with acoustic adaptation
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