Publications

Refine Results

(Filters Applied) Clear All

The MIT-LL/AFRL IWSLT-2007 MT System

October 15, 2007
  |
Conference Paper
Author:
Wade Shen
…
Published in:
Int. Workshop on Spoken Language Translation, IWSLT, 15-16 October 2007.
Topic:
machine translation
R&D area:
R&D group:

Summary

The MIT-LL/AFRL MT system implements a standard phrase-based, statistical translation model. It incorporates a number of extensions that improve performance for speech-based translation. During this evaluation our efforts focused on the rapid porting of our SMT system to a new language (Arabic) and novel approaches to translation from speech input. This paper discusses the architecture of the MIT-LL/AFRL MT system, improvements over our 2007 system, and experiments we ran during the IWSLT-2007 evaluation. Specifically, we focus on 1) experiments comparing the performance of confusion network decoding and direct lattice decoding techniques for speech machine translation, 2) the application of lightweight morphology for Arabic MT pre-processing and 3) improved confusion network decoding.
READ LESS

Summary

The MIT-LL/AFRL MT system implements a standard phrase-based, statistical translation model. It incorporates a number of extensions that improve performance for speech-based translation. During this evaluation our efforts focused on the rapid porting of our SMT system to a new language (Arabic) and novel approaches to translation from speech input...

READ MORE
The MIT-LL/AFRL IWSLT-2007 MT System

Design of an optical photon counting array receiver system for deep-space communications

October 1, 2007
  |
Journal Article
Author:
Jeffrey A. Mendenhall
…
Published in:
Proc. of the IEEE, Vol. 95, No. 10, October 2007, pp. 2059-2069.
Topic:
photonics
R&D area:
R&D group:

Summary

Demand for increased capacity in deep-space to Earth communications systems continues to rise as sensor data rates climb and mission requirements expand. Optical freespace laser communications systems offer the potential for operating at data rates 10 to 1000 times that of current radiofrequency systems. A key element in an optical communications system is the Earth receiver. This paper reviews the design of a distributed photon-counting receiver array composed of four meter-class telescopes, developed as a part of the Mars Laser Communications Demonstration (MLCD) project. This design offers a cost-effective and adaptable alternative approach to traditional large, single-aperture receive elements while preserving the expected improvement in data rates enabled by free-space laser communications systems. Key challenges in developing distributed receivers and details of the MLCD design are discussed.
READ LESS

Summary

Demand for increased capacity in deep-space to Earth communications systems continues to rise as sensor data rates climb and mission requirements expand. Optical freespace laser communications systems offer the potential for operating at data rates 10 to 1000 times that of current radiofrequency systems. A key element in an optical...

READ MORE
Design of an optical photon counting array receiver system for deep-space communications

Scaling three-dimensional SOI integrated-circuit technology

October 1, 2007
  |
Conference Paper
Author:
Chenson K. Chen
…
Published in:
2007 IEEE Int. SOI Conf. Proc., 1-4 October 2007, pp. 87-88.
Topic:
integrated circuit
R&D area:
R&D group:

Summary

Introduction At Lincoln Laboratory, we have established a three dimensional (3D) integrated circuit (IC) technology that has been developed and demonstrated over seven designs, bonding two or three active circuit layers or tiers to form monolithically integrated 3D circuits. Key features of our 3DIC technology include fully depleted SOI (FDSOI) circuit fabrication, low-temperature wafer-scale oxide-to-oxide bonding, precision wafer-to-wafer alignment, and dense unrestricted 3D vias interconnecting stacked circuit layers, successfully demonstrated in a large area 8 x 8 mm2 high-3D-via-count 1024 x 1024 visible imager. In this paper, we describe details of our bonding protocol for 150-mm diameter wafers, leading to a 50% increase in oxide-oxide bond strength and demonstration of +--0.5 am wafer-to-wafer alignment accuracy. We have established design rules for our 3DIC technology, have quantified process factors limiting our design-rule 3D via pitch, and have demonstrated next generation 3D vias with a 2x size reduction, stacked 3D vias, a backmetal interconnect process to reduce 2D circuit exclusion zones, and buried oxide (BOX) vias to allow both electrical and thermal substrate connections. All of these improvements will allow us to continue to reduce minimum 3D via pitch and reduce 2D layout limitations, making our 3DIC technology more attractive to a broader range of applications.
READ LESS

Summary

Introduction At Lincoln Laboratory, we have established a three dimensional (3D) integrated circuit (IC) technology that has been developed and demonstrated over seven designs, bonding two or three active circuit layers or tiers to form monolithically integrated 3D circuits. Key features of our 3DIC technology include fully depleted SOI (FDSOI)...

READ MORE
Scaling three-dimensional SOI integrated-circuit technology

An approach to verify a model for translating convective weather information to air traffic management impact

September 18, 2007
  |
Conference Paper
Author:
William N. Chan
…
Published in:
7th AIAA Aviation Technology, Integration, and Operations (ATIO) Conf., 18-20 September 2007.
Topic:
aviation weather
R&D area:
R&D group:

Summary

This paper describes a method to determine the accuracy of the Convective Weather Avoidance Model which predicts the likelihood that pilots will deviate away from specific areas of convective activity. Visual inspection with a reduced data set helped refine the algorithms used in the verification and offered some preliminary results of the model's accuracy in today's airspace. This model has some explanatory power in predicting regions of airspace where pilots are willing to deviate or fly through. In some instances, pilots appeared not to make an early decision to deviate around convective weather and continued on course as the region appeared more passable when they reached it. In other instances, pilots skirted the edges of regions where the model expected pilots avoid. This behavior suggests edge areas of those model regions were more passable and the convection in that region was not uniform in intensity.
READ LESS

Summary

This paper describes a method to determine the accuracy of the Convective Weather Avoidance Model which predicts the likelihood that pilots will deviate away from specific areas of convective activity. Visual inspection with a reduced data set helped refine the algorithms used in the verification and offered some preliminary results...

READ MORE
An approach to verify a model for translating convective weather information to air traffic management impact

Model estimates of traffic reduction in storm impacted en route airspace

September 18, 2007
  |
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.
READ LESS

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...

READ MORE
Model estimates of traffic reduction in storm impacted en route airspace

Evaluation of potential NEXRAD dual polarization products

September 4, 2007
  |
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.
READ LESS

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...

READ MORE
Evaluation of potential NEXRAD dual polarization products

Classification methods for speaker recognition

September 1, 2007
  |
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.
READ LESS

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...

READ MORE
Classification methods for speaker recognition

Speaker verification using support vector machines and high-level features

September 1, 2007
  |
Journal Article
Author:
William M. Campbell
…
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.
READ LESS

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...

READ MORE
Speaker verification using support vector machines and high-level features

pMATLAB parallel MATLAB library

September 1, 2007
  |
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.
READ LESS

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)...

READ MORE
pMATLAB parallel MATLAB library

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

August 27, 2007
  |
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.
READ LESS

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...

READ MORE
A comparison of speaker clustering and speech recognition techniques for air situational awareness
1201-1210 of 2315