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Geiger-mode avalanche photodiodes for three-dimensional imaging

January 1, 2002
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Journal Article
Author:
Brian F. Aull
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Published in:
Lincoln Laboratory Journal, Vol. 13, No. 2, 2002, pp. 335-350.
Topic:
ladar
R&D area:
R&D group:

Summary

We discuss the properties of Geiger-mode avalanche photodiodes (APDs) and their use in developing an imaging laser radar (ladar). This type of photodetector gives a fast electrical pulse in response to the detection of even a single photon, allowing for sub-nsec-precision photon-flight-time measurement. We present ongoing work at Lincoln Laboratory on three-dimensional (3D) imaging with arrays of these diodes, and the integration of the arrays with fast complementary metal-oxide semiconductor (CMOS) digital timing circuits.
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Summary

We discuss the properties of Geiger-mode avalanche photodiodes (APDs) and their use in developing an imaging laser radar (ladar). This type of photodetector gives a fast electrical pulse in response to the detection of even a single photon, allowing for sub-nsec-precision photon-flight-time measurement. We present ongoing work at Lincoln Laboratory...

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Geiger-mode avalanche photodiodes for three-dimensional imaging

Silicon-on-insulator-based single-chip image sensors: low-voltage scientific imaging

January 1, 2002
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Conference Paper
Author:
Vyshnavi Suntharalingam
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Published in:
Experimental Astronomy, Vol. 14, No. 2, 2002, pp. 91-98.
Topic:
sensors
R&D area:
R&D group:

Summary

A low-voltage (
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Summary

A low-voltage (

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Silicon-on-insulator-based single-chip image sensors: low-voltage scientific imaging

The physical origin of the land-ocean contrast in lightning activity

January 1, 2002
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Journal Article
Author:
Earle R. Williams
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Published in:
Comptes Rendus Physique, Vol. 3, No. 10, 2002, pp. 1277-1292.
Topic:
weather
R&D area:
R&D group:

Summary

New tests and older ideas are explored to understand the origin of the pronounced contrast in lightning between land and sea. The behavior of islands as miniature continents with variable area supports the traditional thermal hypothesis over the aerosol hypothesis for lightning control. The substantial land-ocean contrast in updraft strength is supported globally by TRMM (Tropical Rainfall Measuring Mission) radar comparisons of mixed phase radar reflectivity. The land-ocean updraft contrast is grossly inconsistent with the land ocean contrast in CAPE (Convective Available Potential Energy), from the standpoint of parcel theory. This inconsistency is resolved by the scaling of buoyant parcel size with cloud base height, as suggested by earlier investigators. Strongly electrified continental convection is then favored by a larger surface Bowen ratio, and by larger, more strongly buoyant boundary layer parcels which more efficiently transform CAPE to kinetic energy of the updraft in the moist stage of conditional instability.
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Summary

New tests and older ideas are explored to understand the origin of the pronounced contrast in lightning between land and sea. The behavior of islands as miniature continents with variable area supports the traditional thermal hypothesis over the aerosol hypothesis for lightning control. The substantial land-ocean contrast in updraft strength...

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The physical origin of the land-ocean contrast in lightning activity

Gender-dependent phonetic refraction for speaker recognition

January 1, 2002
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Conference Paper
Author:
Walter D. Andrews
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Published in:
Proc. IEEE Int. Conf. on Acoustics, Speech and Signal Processing, ICASSP, 13-17 May 2002, Vol. 1, pp. 149-152.
Topic:
speaker recognition
R&D area:
R&D group:

Summary

This paper describes improvement to an innovative high-performance speaker recognition system. Recent experiments showed that with sufficient training data phone strings from multiple languages are exceptional features for speaker recognition. The prototype phonetic speaker recognition system used phone sequences from six languages to produce an equal error rate of 11.5% on Switchboard-I audio files. The improved system described in this paper reduces the equal error rate to less than 4%. This is accomplished by incorporating gender-dependent phone models, pre-processing the speech files to remove cross-talk, and developing more sophisticated fusion techniques for the multi-language likelihood scores.
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Summary

This paper describes improvement to an innovative high-performance speaker recognition system. Recent experiments showed that with sufficient training data phone strings from multiple languages are exceptional features for speaker recognition. The prototype phonetic speaker recognition system used phone sequences from six languages to produce an equal error rate of 11.5%...

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Gender-dependent phonetic refraction for speaker recognition

Language identification using Gaussian mixture model tokenization

January 1, 2002
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Conference Paper
Author:
Pedro A. Torres-Carrasquillo
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Published in:
Proc. IEEE Int. Conf., on Acoustics, Speech and Signal Processing, ICASSP, Vol. I, 13-17 May 2002, pp. I-757 - I-760.
Topic:
language recognition
R&D area:
R&D group:

Summary

Phone tokenization followed by n-gram language modeling has consistently provided good results for the task of language identification. In this paper, this technique is generalized by using Gaussian mixture models as the basis for tokenizing. Performance results are presented for a system employing a GMM tokenizer in conjunction with multiple language processing and score combination techniques. On the 1996 CallFriend LID evaluation set, a 12-way closed set error rate of 17% was obtained.
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Summary

Phone tokenization followed by n-gram language modeling has consistently provided good results for the task of language identification. In this paper, this technique is generalized by using Gaussian mixture models as the basis for tokenizing. Performance results are presented for a system employing a GMM tokenizer in conjunction with multiple...

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Language identification using Gaussian mixture model tokenization

Interlingua-based English-Korean two-way speech translation of doctor-patient dialogues with CCLINC

January 1, 2002
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Journal Article
Author:
Young-Suk Lee
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Published in:
Machine Trans. Vol. 17, No. 3, 2002, pp. 213-243.
Topic:
machine translation
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Summary

Development of a robust two-way real-time speech translation system exposes researchers and system developers to various challenges of machine translation (MT) and spoken language dialogues. The need for communicating in at least two different languages poses problems not present for a monolingual spoken language dialogue system, where no MT engine is embedded within the process flow. Integration of various component modules for real-time operation poses challenges not present for text translation. In this paper, we present the CCLINC (Common Coalition Language System at Lincoln Laboratory) English-Korean two-way speech translation system prototype trained on doctor-patient dialogues, which integrates various techniques to tackle the challenges of automatic real-time speech translation. Key features of the system include (i) language-independent meaning representation which preserves the hierarchical predicate-argument structure of an input utterance, providing a powerful mechanism for discourse understanding of utterances originating from different languages, word-sense disambiguation and generation of various word orders of many languages, (ii) adoption of the DARPA Communicator architecture, a plug-and-play distributed system architecture which facilitates integration of component modules and system operation in real time, and (iii) automatic acquisition of grammar rules and lexicons for easy porting of the system to different languages and domains. We describe these features in detail and present experimental results.
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Summary

Development of a robust two-way real-time speech translation system exposes researchers and system developers to various challenges of machine translation (MT) and spoken language dialogues. The need for communicating in at least two different languages poses problems not present for a monolingual spoken language dialogue system, where no MT engine...

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Interlingua-based English-Korean two-way speech translation of doctor-patient dialogues with CCLINC

Detecting clusters of galaxies in the Sloan Digital Sky Survey. I. Monte Carlo comparison of cluster detection algorithms

January 1, 2002
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Journal Article
Author:
Rita Seung Jung Kim
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Published in:
Astron. J., Vol. 123, No. 1, January 2002, pp. 20-36.
Topic:
space
R&D area:
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Summary

We present a comparison of three cluster-finding algorithms from imaging data using Monte Carlo simulations of clusters embedded in a 25 deg(2) region of Sloan Digital Sky Survey (SDSS) imaging data: the matched filter (MF), the adaptive matched filter (AMF), and a color-magnitude filtered Voronoi tessellation technique (VTT). Among the two matched filters, we find that the MF is more efficient in detecting faint clusters, whereas the AMF evaluates the redshifts and richnesses more accurately, therefore suggesting a hybrid method (HMF) that combines the two. The HMF outperforms the VTT when using a background that is uniform, but it is more sensitive to the presence of a nonuniform galaxy background than is the VTT; this is due to the assumption of a uniform background in the HMF model. We thus find that for the detection thresholds we determine to be appropriate for the SDSS data, the performance of both algorithms are similar; we present the selection function for each method evaluated with these thresholds as a function of redshift and richness. For simulated clusters generated with a Schechter luminosity function (M(*r) = -21.5 and (a = -1.1), both algorithms are complete for Abell richness >~ clusters up to z ~0.4 for a sample magnitude limited to r = 21. While the cluster parameter evaluation shows a mild correlation with the local background density, the detection efficiency is not significantly affected by the background fluctuations, unlike previous shallower surveys.
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Summary

We present a comparison of three cluster-finding algorithms from imaging data using Monte Carlo simulations of clusters embedded in a 25 deg(2) region of Sloan Digital Sky Survey (SDSS) imaging data: the matched filter (MF), the adaptive matched filter (AMF), and a color-magnitude filtered Voronoi tessellation technique (VTT). Among the...

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Detecting clusters of galaxies in the Sloan Digital Sky Survey. I. Monte Carlo comparison of cluster detection algorithms

Discrete optimization using decision-directed learning for distributed networked computing

January 1, 2002
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Conference Paper
Author:
Joel I. Goodman
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Published in:
36th Asilomar Conf. on Signals, Systems and Computers, Vol. 2, 3-6 November 2002, pp. 1189-1196.
Topic:
high performance computing
R&D area:
R&D group:

Summary

Decision-directed learning (DDL) is an iterative discrete approach to finding a feasible solution for large-scale combinatorial optimization problems. DDL is capable of efficiently formulating a solution to network scheduling problems that involve load limiting device utilization, selecting parallel configurations for software applications and host hardware using a minimum set of resources, and meeting time-to-result performance requirements in a dynamic network environment. This paper quantifies the algorithms that constitute DDL and compares its performance to other popular combinatorial self-directed real-time networked resource configuration for dynamically building a mission specific signal-processor for real-time distributed and parallel applications.
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Summary

Decision-directed learning (DDL) is an iterative discrete approach to finding a feasible solution for large-scale combinatorial optimization problems. DDL is capable of efficiently formulating a solution to network scheduling problems that involve load limiting device utilization, selecting parallel configurations for software applications and host hardware using a minimum set of...

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Discrete optimization using decision-directed learning for distributed networked computing

The effect of personality type on the usage of a multimedia engineering education system

January 1, 2002
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Journal Article
Author:
Albert I. Reuther
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Published in:
32nd Annual ASEE/IEEE Frontiers in Education Conf., 6-9 November 2002, pp. T3A-7 - T3A-12.
Topic:
computing
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Summary

Multimedia education has quickly entered our classrooms and offices providing tutorials and lessons on many different topics. The assumption that most people interact with these multimedia systems in similar ways can easily be made, but are these assumptions valid? What factors determine whether students will embrace computer-based multimedia-augmented learning? One factor may be the student's personality type. This paper explores the reasons why some students may enjoy learning using computer-based educational delivery systems while others may have absolutely no enthusiasm for this type of learning and how that enthusiasm may relate to the students' personality types.
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Summary

Multimedia education has quickly entered our classrooms and offices providing tutorials and lessons on many different topics. The assumption that most people interact with these multimedia systems in similar ways can easily be made, but are these assumptions valid? What factors determine whether students will embrace computer-based multimedia-augmented learning? One...

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The effect of personality type on the usage of a multimedia engineering education system

PVL: An Object Oriented Software Library for Parallel Signal Processing (Abstract)

January 1, 2002
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Conference Paper
Author:
Edward M. Rutledge
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Published in:
CLUSTER '01, 2001 IEEE Int. Conf. on Cluster Computing, 8-11 October 2001, p. 74.
Topic:
signal processing
R&D area:
R&D group:

Summary

Real-time signal processing consumes the majority of the world's computing power Increasingly, programmable parallel microprocessors are used to address a wide variety of signal processing applications (e.g. scientific, video, wireless, medical, communication, encoding, radar, sonar and imaging). In programmable systems the major challenge is no longer hardware but software. Specifically, the key technical hurdle lies in mapping (i.e., placement and routing) of an algorithm onto a parallel computer in a general manner that preserves software portability. We have developed the Parallel Vector Library (PVL) to allow signal processing algorithms to be written using high level Matlab like constructs that are independent of the underlying parallel mapping. Programs written using PVL can be ported to a wide range of parallel computers without sacrificing performance. Furthermore, the mapping concepts in PVL provide the infrastructure for enabling new capabilities such as fault tolerance, dynamic scheduling and self-optimization. This presentation discusses PVL with particular emphasis on quantitative comparisons with standard parallel signal programming practices.
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Summary

Real-time signal processing consumes the majority of the world's computing power Increasingly, programmable parallel microprocessors are used to address a wide variety of signal processing applications (e.g. scientific, video, wireless, medical, communication, encoding, radar, sonar and imaging). In programmable systems the major challenge is no longer hardware but software. Specifically...

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PVL: An Object Oriented Software Library for Parallel Signal Processing (Abstract)
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