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Variability compensated support vector machines applied to speaker verification

September 6, 2009
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Conference Paper
Author:
Zahi N. Karam
…
Published in:
INTERSPEECH 2009, Proc. of the 10th Annual Conf. of the Internatinoal Speech Communication Association, 6-9 September 2009, pp. 1555-1558.
Topic:
speaker recognition
R&D area:
R&D group:

Summary

Speaker verification using SVMs has proven successful, specifically using the GSV Kernel [1] with nuisance attribute projection (NAP) [2]. Also, the recent popularity and success of joint factor analysis [3] has led to promising attempts to use speaker factors directly as SVM features [4]. NAP projection and the use of speaker factors with SVMs are methods of handling variability in SVM speaker verification: NAP by removing undesirable nuisance variability, and using the speaker factors by forcing the discrimination to be performed based on inter-speaker variability. These successes have led us to propose a new method we call variability compensated SVM (VCSVM) to handle both inter and intra-speaker variability directly in the SVM optimization. This is done by adding a regularized penalty to the optimization that biases the normal to the hyperplane to be orthogonal to the nuisance subspace or alternatively to the complement of the subspace containing the inter-speaker variability. This bias will attempt to ensure that inter-speaker variability is used in the recognition while intra-speaker variability is ignored. In this paper we present the theory and promising results on nuisance compensation.
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Summary

Speaker verification using SVMs has proven successful, specifically using the GSV Kernel [1] with nuisance attribute projection (NAP) [2]. Also, the recent popularity and success of joint factor analysis [3] has led to promising attempts to use speaker factors directly as SVM features [4]. NAP projection and the use of...

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Variability compensated support vector machines applied to speaker verification

Beam combining of quantum cascade laser arrays

August 31, 2009
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Journal Article
Author:
Benjamin G. Lee
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Published in:
Opt. Express, Vol. 17, No. 18, 31 August 2009, pp. 16216-16224.
Topic:
lasers
R&D area:
R&D group:

Summary

Wavelength beam combining was used to co-propagate beams from 28 elements in an array of distributed-feedback quantum cascade lasers (DFB-QCLs). The beam-quality product of the array, defined as the product of near-field spot size and far-field divergence for the entire array, was improved by a factor of 21 by using wavelength beam combining. To demonstrate the applicability of wavelength beam combined DFB-QCL arrays for remote sensing, we obtained the absorption spectrum of isopropanol at a distance of 6 m from the laser array.
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Summary

Wavelength beam combining was used to co-propagate beams from 28 elements in an array of distributed-feedback quantum cascade lasers (DFB-QCLs). The beam-quality product of the array, defined as the product of near-field spot size and far-field divergence for the entire array, was improved by a factor of 21 by using...

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Beam combining of quantum cascade laser arrays

High density plasma etching of titanium nitride metal gate electrodes for fully depleted silicon-on-insulator subthreshold transistor integration

August 1, 2009
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Journal Article
Author:
Steven A. Vitale
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Published in:
J. Vacuum Sci. Technol. B, Microelectron. Process. Phenon., Vol. 27, No. 6, p. 2472-2479.
Topic:
advanced materials
R&D area:

Summary

Etching of TiN metal gate materials as a part of an integrated flow to fabricate fully depleted silicon-on-insulator ultralow-power transistors is reported. TiN etching is characterized as a function of source power, bias power, gas composition, and substrate temperature in a high density inductively coupled plasma reactor. Under the conditions used in this work, the TiN etch rate appears to be ion flux limited and exhibits a low ion enhanced etching activation energy of 0.033 eV. Notching of the polysilicon layer above the TiN may occur during the polysilicon overetch step as well as the TiN overetch step. Notching is not significantly affected by charging of the underlying gate dielectric under the conditions used. By optimizing the plasma etch process conditions, TiN:SiO2 selectivity of nearly 1000:1 is achieved, and a two-step TiN main etch and TiN overetch process yields well-defined metal gate structures without severe gate profile artifacts.
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Summary

Etching of TiN metal gate materials as a part of an integrated flow to fabricate fully depleted silicon-on-insulator ultralow-power transistors is reported. TiN etching is characterized as a function of source power, bias power, gas composition, and substrate temperature in a high density inductively coupled plasma reactor. Under the conditions...

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High density plasma etching of titanium nitride metal gate electrodes for fully depleted silicon-on-insulator subthreshold transistor integration

New generation of digital microfluidic devices

August 1, 2009
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Journal Article
Author:
Jakub T. Kedzierski
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Published in:
J. Microelectromech. Syst., Vol. 18, No. 4, August 2009, pp. 845-851.
Topic:
microfluidics
R&D area:

Summary

This paper reports on the design, fabrication, and performance of micro-sized fluidic devices that use electrowetting to control and transport liquids. Using standard microfabrication techniques, new pumping systems are developed with significantly more capability than open digital microfluidic systems that are often associated with electrowetting. This paper demonstrates that, by integrating closed microchannels with different channel heights and using electrowetting actuation, liquid interfaces can be controlled, and pressure work can be done, resulting in fluid pumping. The operation of two different on-chip pumps and devices that can form water drops is described. In addition, a theory is presented to explain the details of single-electrode actuation in a closed channel.
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Summary

This paper reports on the design, fabrication, and performance of micro-sized fluidic devices that use electrowetting to control and transport liquids. Using standard microfabrication techniques, new pumping systems are developed with significantly more capability than open digital microfluidic systems that are often associated with electrowetting. This paper demonstrates that, by...

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New generation of digital microfluidic devices

Roadmap for weather integration into Traffic Flow Management Modernization (TFM-M)

July 24, 2009
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Project Report
Author:
James E. Evans
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Published in:
MIT Lincoln Laboratory Report ATC-347
Topic:
air traffic control
R&D area:
R&D group:

Summary

This report provides recommendations for aligning new Collaborative Air Traffic Management Technologies (CATM-T) with evolving aviation weather products to improve NAS efficiency during adverse (especially severe) weather conditions. Key gaps identified include 1. Improving or developing pilot convective storm avoidance models as well as models for route blockage and capacity in severe weather is necessary for automated congestion prediction and resolution. 2. Forecasts need to characterize uncertainty that can be used by CATM tools and, explicitly forecast key parameters needed for translation of weather products to capacity impacts. 3. Time based flow management will require substantial progress in both the translation modeling and in predicting appropriate storm avoidance trajectories. Near term efforts should focus on integration of the Traffic Management Advisor (TMA) with contemporary severe weather products such as the Corridor Integrated Weather System (CIWS). 4. Human factors studies on product design to improve individual decision making, improved collaborative decision making in "difficult" situations, and the use of probabilistic products are also essential. 5. Studies need to be carried out to determine how well en route and terminal capacity currently is being utilized during adverse weather events so as to identify the highest priority areas for integrated weather-CATM system development.
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Summary

This report provides recommendations for aligning new Collaborative Air Traffic Management Technologies (CATM-T) with evolving aviation weather products to improve NAS efficiency during adverse (especially severe) weather conditions. Key gaps identified include 1. Improving or developing pilot convective storm avoidance models as well as models for route blockage and capacity...

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Roadmap for weather integration into Traffic Flow Management Modernization (TFM-M)

Graphene-on-insulator transistors made using C on Ni chemical-vapor deposition

July 1, 2009
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Journal Article
Author:
Jakub T. Kedzierski
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Published in:
IEEE Electron Device Lett., Vol. 30, No. 7, July 2009, pp. 745-747.
Topic:
fabrication
R&D area:

Summary

Graphene transistors are made by transferring a thin graphene film grown on Ni onto an insulating SiO2 substrate. The properties and integration of these graphene-on-insulator transistors are presented and compared to the characteristics of devices made from graphitized SiC and exfoliated graphene flakes.
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Summary

Graphene transistors are made by transferring a thin graphene film grown on Ni onto an insulating SiO2 substrate. The properties and integration of these graphene-on-insulator transistors are presented and compared to the characteristics of devices made from graphitized SiC and exfoliated graphene flakes.

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Graphene-on-insulator transistors made using C on Ni chemical-vapor deposition

The Route Availability Planning Tool (RAPT): evaluation of departure management decision support in New York during the 2008 convective weather season

June 29, 2009
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Conference Paper
Author:
Richard A. DeLaura
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Published in:
8th USA/Europe Air Traffic Management Research and Development Sem., ATM 2009, 29 June - 2 July 2009.
Topic:
air traffic control
R&D area:
R&D group:

Summary

Severe weather avoidance programs (SWAP) due to convective weather are common in many of the busiest terminal areas in the US National Airspace System (NAS). In order to make efficient use of available airspace in rapidly evolving convective weather, it is necessary to predict the impacts of the weather on key resources (e.g., departure and arrival routes and fixes), with frequent updates as the weather changes. Currently, this prediction is a mental process that imposes a significant cognitive burden on air traffic managers. As a result, air traffic management in SWAP is often inconsistent and decisions result in less than optimal performance. The Route Availability Planning Tool (RAPT) is a prototype automated decision support tool, intended to help air traffic managers in convective weather SWAP, by predicting the impacts of convective weather on departure routes. Originally deployed in New York in August, 2002, RAPT has recently undergone two field evaluations (2007 and 2008) in order to test and refine its concept of operations, evaluate the accuracy and usefulness of its decision guidance, and estimate observed and potential delay reduction benefits that may be achieved as a result of its use. This paper presents the results of the 2008 performance evaluation, focusing on the concept of operations and the quality of decision support guidance. A second paper [1] presents analyses of delay reduction benefits and the operational decision making environment in which RAPT is deployed.
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Summary

Severe weather avoidance programs (SWAP) due to convective weather are common in many of the busiest terminal areas in the US National Airspace System (NAS). In order to make efficient use of available airspace in rapidly evolving convective weather, it is necessary to predict the impacts of the weather on...

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The Route Availability Planning Tool (RAPT): evaluation of departure management decision support in New York during the 2008 convective weather season

Automatic registration of LIDAR and optical images of urban scenes

June 20, 2009
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Conference Paper
Author:
Andrew Mastin
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Published in:
CVPR 2009, IEEE Conf. on Computer Vision and Pattern Recognition, 20-25 June 2009, pp. 2639-2646.
Topic:
ladar
R&D area:
R&D group:

Summary

Fusion of 3D laser radar (LIDAR) imagery and aerial optical imagery is an efficient method for constructing 3D virtual reality models. One difficult aspect of creating such models is registering the optical image with the LIDAR point cloud, which is characterized as a camera pose estimation problem. We propose a novel application of mutual information registration methods, which exploits the statistical dependency in urban scenes of optical apperance with measured LIDAR elevation. We utilize the well known downhill simplex optimization to infer camera pose parameters. We discuss three methods for measuring mutual information between LIDAR imagery and optical imagery. Utilization of OpenGL and graphics hardware in the optimization process yields registration times dramatically lower than previous methods. Using an initial registration comparable to GPS/INS accuracy, we demonstrate the utility of our algorithm with a collection of urban images and present 3D models created with the fused imagery.
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Summary

Fusion of 3D laser radar (LIDAR) imagery and aerial optical imagery is an efficient method for constructing 3D virtual reality models. One difficult aspect of creating such models is registering the optical image with the LIDAR point cloud, which is characterized as a camera pose estimation problem. We propose a...

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Automatic registration of LIDAR and optical images of urban scenes

Compressed sensing arrays for frequency-sparse signal detection and geolocation

June 15, 2009
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Conference Paper
Author:
Benjamin A. Miller
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Published in:
Proc. of the 2009 DoD High Performance Computing Modernization Program Users Group Conf., HPCMP-UGC, 15 June 2009, pp. 297-301.
Topic:
signal processing
R&D area:
R&D group:

Summary

Compressed sensing (CS) can be used to monitor very wide bands when the received signals are sparse in some basis. We have developed a compressed sensing receiver architecture with the ability to detect, demodulate, and geolocate signals that are sparse in frequency. In this paper, we evaluate detection, reconstruction, and angle of arrival (AoA) estimation via Monte Carlo simulation and find that, using a linear 4- sensor array and undersampling by a factor of 8, we achieve near-perfect detection when the received signals occupy up to 5% of the bandwidth being monitored and have an SNR of 20 dB or higher. The signals in our band of interest include frequency-hopping signals detected due to consistent AoA. We compare CS array performance using sensor-frequency and space-frequency bases, and determine that using the sensor-frequency basis is more practical for monitoring wide bands. Though it requires that the received signals be sparse in frequency, the sensor-frequency basis still provides spatial information and is not affected by correlation between uncompressed basis vectors.
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Summary

Compressed sensing (CS) can be used to monitor very wide bands when the received signals are sparse in some basis. We have developed a compressed sensing receiver architecture with the ability to detect, demodulate, and geolocate signals that are sparse in frequency. In this paper, we evaluate detection, reconstruction, and...

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Compressed sensing arrays for frequency-sparse signal detection and geolocation

Machine translation for government applications

June 1, 2009
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Journal Article
Author:
Douglas A. Jones
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Published in:
Lincoln Laboratory Journal, Vol. 18, No. 1, June 2009, pp. 41-53.
Topic:
machine translation
R&D area:
R&D group:

Summary

The idea of a mechanical process for converting one human language into another can be traced to a letter written by René Descartes in 1629, and after nearly 400 years, this vision has not been fully realized. Machine translation (MT) using digital computers has been a grand challenge for computer scientists, mathematicians, and linguists since the first international conference on MT was held at the Massachusetts Institute of Technology in 1952. Currently, Lincoln Laboratory is achieving success in a highly focused research program that specializes in developing speech translation technology for limited language resource domains and in adapting foreign-language proficiency standards for MT evaluation. Our specialized research program is situated within a general framework for multilingual speech and text processing for government applications.
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Summary

The idea of a mechanical process for converting one human language into another can be traced to a letter written by René Descartes in 1629, and after nearly 400 years, this vision has not been fully realized. Machine translation (MT) using digital computers has been a grand challenge for computer...

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Machine translation for government applications
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