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Parallel programming with MatlabMPI

July 20, 2001
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Journal Article
Author:
Jeremy Kepner
Published in:
https://arxiv.org/abs/astro-ph/0107406
Topic:
high performance computing
R&D area:
R&D group:

Summary

MatlabMPI is a Matlab implementation of the Message Passing Interface (MPI) standard and allows any Matlab program to exploit multiple processors. MatlabMPI currently implements the basic six functions that are the core of the MPI point-to-point communications standard. The key technical innovation of MatlabMPI is that it implements the widely used MPI "look and feel" on top of standard Matlab file I/O, resulting in an extremely compact (~100 lines) and "pure" implementation which runs anywhere Matlab runs. The performance has been tested on both shared and distributed memory parallel computers. MatlabMPI can match the bandwidth of C based MPI at large message sizes. A test image filtering application using MatlabMPI achieved a speedup of ~70 on a parallel computer.
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Summary

MatlabMPI is a Matlab implementation of the Message Passing Interface (MPI) standard and allows any Matlab program to exploit multiple processors. MatlabMPI currently implements the basic six functions that are the core of the MPI point-to-point communications standard. The key technical innovation of MatlabMPI is that it implements the widely...

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Parallel programming with MatlabMPI

Initial flight test results from the EO-1 Advanced Land Imager: radiometric performance

July 9, 2001
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Conference Paper
Author:
Jeffrey A. Mendenhall
…
Published in:
IGARSS 2001, Int. Geoscience and Remote Sensing Symp., Vol. 1, 9-13 July 2001, pp. 515-417.
Topic:
remote sensing
R&D area:
R&D group:

Summary

The Advanced Land Imager (ALI) is one of three instruments flown on the first Earth Observing mission (EO-1) under NASA's New Millennium Program (NMP). The primary NMP mission objective is to flight-validate advanced technologies that will enable dramatic improvements in performance, cost, mass and schedule for future, Landsat-like, earth remote sensing instruments. ALI contains a number of innovative features, including all the Category 1 technology demonstrations of the EO-1 mission. These include the basic instrument architecture which employs a push-broom data collection mode, a wide field of view optical design, compact multispectral detector arrays, non-cryogenic HgCdTe for the short wave infrared bands, silicon carbide optics and a multi-level solar calibration technique. The Earth Observing-1 spacecraft was successfully launched on November 21, 2000. During the first sixty days on orbit, several Earth scenes were collected and on-orbit calibration techniques were exercised by the Advanced Land Imager. This paper presents the status of ALI radiometric performance characterization obtained from the data collected during that period.
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Summary

The Advanced Land Imager (ALI) is one of three instruments flown on the first Earth Observing mission (EO-1) under NASA's New Millennium Program (NMP). The primary NMP mission objective is to flight-validate advanced technologies that will enable dramatic improvements in performance, cost, mass and schedule for future, Landsat-like, earth remote...

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Initial flight test results from the EO-1 Advanced Land Imager: radiometric performance

TCWF algorithm assessment - Memphis 2000

July 9, 2001
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Project Report
Author:
Kim E. Theriault
…
Published in:
MIT Lincoln Laboratory Report ATC-297
Topic:
weather
R&D area:
R&D group:

Summary

This report describes a formal Assessment of the Terminal Convective Weather Forecast (TCWF) algorithm, developed under the FAA Aviation Weather Research Program by MIT Lincoln Laboratory as part of the Convective Weather Product Development Team (PDT). TCWF is proposed as a Pre-Planned Product Improvement (P3I) enhancement to the operational ITWS currently scheduled for deployment at major airports in 2002. The TCWF Assessment in Memphis, TN ran from 24 March to 30 September 2000. The performance of TCWF was excellent on the large scale, organized storm systems it was designed to predict, and the software was extremely stable during the Assessment. Small changes to the algorithm parameters were made as a result of the 2000 testing. The TCWF performance can be improved on airmass storms and on forecasting new growth and subsequent decay of large-scale storms. These are active areas of research for future ITWS P3I builds.
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Summary

This report describes a formal Assessment of the Terminal Convective Weather Forecast (TCWF) algorithm, developed under the FAA Aviation Weather Research Program by MIT Lincoln Laboratory as part of the Convective Weather Product Development Team (PDT). TCWF is proposed as a Pre-Planned Product Improvement (P3I) enhancement to the operational ITWS...

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TCWF algorithm assessment - Memphis 2000

Comparison of two flat reflector-type designs for dual-polarization, dual-band operation

July 8, 2001
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Conference Paper
Author:
Sean M. Duffy
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Published in:
IEEE Antennas and Propagation Society Int. Synp. 2001 Digest, Vol. 2, 8-13 July 2001, pp. 288-291.
Topic:
antennas
R&D area:
R&D group:

Summary

The parabolic reflector remains an essential antenna for high-gain applications. This is a result of its desirable characteristics based on geometric optics. These include relative frequency independence for sufficiently large apertures and high aperture efficiency. However, the parabolic reflector occupies a large volume. This may be aesthetically unappealing on the sides of buildings and structures. Also, from a mobile user perspective, a desirable characteristic is having a large aperture during operation while having a small volume when packed away and not in use. The parabolic reflector is typically constructed of multiple petals for mobile uses, but it does not pack into as small a volume as a flat, thin antenna would due to the curvature of the paraboloid. Therefore, the primary goal of the antennas studied in this work is developing flat reflector antennas to utilize the advantages of large reflector apertures while remaining capable of packing into a small volume. In addition, system requiremenls dictated dual-band, dual-polarized operation. Two flat reflectors are compared: a reflectarray and a zoned reflector. While each design is inherently narrow-band, methods of achieving dual-band operation were employed.
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Summary

The parabolic reflector remains an essential antenna for high-gain applications. This is a result of its desirable characteristics based on geometric optics. These include relative frequency independence for sufficiently large apertures and high aperture efficiency. However, the parabolic reflector occupies a large volume. This may be aesthetically unappealing on the...

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Comparison of two flat reflector-type designs for dual-polarization, dual-band operation

The radar Correlation and Interpolation (C&I) algorithms deployed in the ASR-9 Processor Augmentation Card (9PAC)

June 29, 2001
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Project Report
Author:
Gabriel R. Elkin
Published in:
MIT Lincoln Laboratory Report ATC-299
Topic:
air traffic control
R&D area:
R&D group:

Summary

The Airport Surveillance Radar 9 (ASR-9) is a terminal radar that was deployed by the Federal Aviation Administration (FAA) during the early 1990's at more than 130 of the busiest airports in the United States. The ASR-9 Processor Augmentation Card (9-PAC), developed at MIT Lincoln Laboratory, is a processor board enhancement for the ASR-9 Array Signal Processor (ASP) that provides increases in processing speed, memory size, and programming. The increased capabilities of the 9PAC hardware made it possible for new surveillance algorithms to be developed in software to provide improved primary radar and beacon surveillance performance. The 9PAC project was developed in two phases. Phase I, which addressed the beacon reflection false target problem, was completed, and is currently being deployed nationwide by the FAA on a plug and play basis. Phase II addresses the primary radar surveillance problems, which include automation of the road and ground clutter censoring process, improving the rejection of false targets, and improving the detection and tracking of aircraft targets. The 9PAC also reduces the life-cycle maintenance cost of the ASR-9 in the Phase II configuration, in which a single 9PAC card replaces four ASP cards. This report describes the improvements to the radar Correlation and Interpolation (C&I) process, which is responsible for creating aircraft target reports and filtering out false targets. [Not Complete]
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Summary

The Airport Surveillance Radar 9 (ASR-9) is a terminal radar that was deployed by the Federal Aviation Administration (FAA) during the early 1990's at more than 130 of the busiest airports in the United States. The ASR-9 Processor Augmentation Card (9-PAC), developed at MIT Lincoln Laboratory, is a processor board...

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The radar Correlation and Interpolation (C&I) algorithms deployed in the ASR-9 Processor Augmentation Card (9PAC)

Speaker recognition from coded speech in matched and mismatched conditions

June 18, 2001
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Conference Paper
Author:
Robert B. Dunn
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Published in:
Proc. 2001: A Speaker Odyssey, The Speaker Recognition Workshop, 18-22 June 2001, pp. 115-20.
Topic:
speaker recognition
R&D area:
R&D group:

Summary

We investigate the effect of speech coding on automatic speaker recognition when training and testing conditions are matched and mismatched. Experiments use standard speech coding algorithms (GSM, G.729, G.723, MELP) and a speaker recognition system based on Gaussian mixture models adapted from a universal background model. There is little loss in recognition performance for toll quality speech coders and slightly more loss when lower quality speech coders are used. Speaker recognition from coded speech using handset dependent score normalization is examined, and we find that this significantly improves performance, particularly when there is a mismatch between training and testing conditions.
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Summary

We investigate the effect of speech coding on automatic speaker recognition when training and testing conditions are matched and mismatched. Experiments use standard speech coding algorithms (GSM, G.729, G.723, MELP) and a speaker recognition system based on Gaussian mixture models adapted from a universal background model. There is little loss...

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Speaker recognition from coded speech in matched and mismatched conditions

Extending the DARPA off-line intrusion detection evaluations

June 12, 2001
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Conference Paper
Author:
Joshua W. Haines
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Published in:
DARPA Information Survivability Conf. and Exposition II, 12-14 June 2001, pp. 35-45.
Topic:
cyber security
R&D area:
R&D group:

Summary

The 1998 and 1999 DARPA off-line intrusion detection evaluations assessed the performance of intrusion detection systems using realistic background traffic and many examples of realistic attacks. This paper discusses three extensions to these evaluations. First, the Lincoln Adaptable Real-time Information Assurance Testbed (LARIAT) has been developed to simplify intrusion detection development and evaluation. LARIAT allows researchers and operational users to rapidly configure and run real-time intrusion detection and correlation tests with robust background traffic and attacks in their laboratories. Second, "Scenario Datasets" have been crafted to provide examples of multiple component attack scenarios instead of the atomic , attacks as found in past evaluations. Third, extensive analysis of the 1999 evaluation data and results has provided understanding of many attacks, their manifestations, and the features used to detect them. This analysis will be used to develop models of attacks, intrusion detection systems, and intrusion detection system alerts. Successful models could reduce the need for expensive experimentation, allow proof-of-concept analysis and simulations, and form the foundation of a theory of intrusion detection.
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Summary

The 1998 and 1999 DARPA off-line intrusion detection evaluations assessed the performance of intrusion detection systems using realistic background traffic and many examples of realistic attacks. This paper discusses three extensions to these evaluations. First, the Lincoln Adaptable Real-time Information Assurance Testbed (LARIAT) has been developed to simplify intrusion detection...

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Extending the DARPA off-line intrusion detection evaluations

SARA: Survivable Autonomic Response Architecture

June 12, 2001
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Conference Paper
Author:
Scott M. Lewandowski
…
Published in:
DARPA Information Survivability Conf. and Exposition II, 12-14 June 2001, pp. 77-88.
Topic:
cyber security
R&D area:
R&D group:

Summary

This paper describes the architecture of a system being developed to defend information systems using coordinated autonomic responses. The system will also be used to test the hypothesis that an effective defense against fast, distributed information attacks requires rapid, coordinated, network-wide responses. The core components of the architecture are a run-time infrastructure (RTI), a communication language, a system model, and defensive components. The RTI incorporates a number of innovative design concepts and provides fast, reliable, exploitation-resistant communication and coordination services to the components defending the network, even when challenged by a distributed attack. The architecture can be tailored to provide scalable information assurance defenses for large, geographically distributed, heterogeneous networks with multiple domains, each of which uses different technologies and requires different policies. The architecture can form the basis of a field-deployable system. An initial version is being developed for evaluation in a testbed that will be used to test the autonomic coordination and response hypothesis.
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Summary

This paper describes the architecture of a system being developed to defend information systems using coordinated autonomic responses. The system will also be used to test the hypothesis that an effective defense against fast, distributed information attacks requires rapid, coordinated, network-wide responses. The core components of the architecture are a...

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SARA: Survivable Autonomic Response Architecture

Detecting low-profile probes and novel denial-of-service attacks

June 1, 2001
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Conference Paper
Author:
Raj Basu
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Published in:
IEEE SMC IA&S Workshop, June 2001.
Topic:
intrusion detection & monitoring
R&D area:
R&D group:

Summary

Attackers use probing attacks to discover host addresses and services available on each host. Once this information is known, an attacker can then issue a denial-of-service attack against the network, a host, or a service provided by a host. These attacks prevent access to the attacked part of the network. Until recently, only simple, easily defeated mechanisms were used for detecting probe attacks. Attackers defeat these mechanisms by creating stealthy low-profile attacks that include only a few, carefully crafted packets sent over an extended period of time. Furthermore, most mechanisms do not allow intrusion analysts to trade off detection rates for false alarm rates. We present an approach to detect stealthy attacks, an architecture for achieving real-time detections with a confidence measure, and the results of evaluating the system. Since the system outputs confidence values, an analyst can trade false alarm rate against detection rate.
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Summary

Attackers use probing attacks to discover host addresses and services available on each host. Once this information is known, an attacker can then issue a denial-of-service attack against the network, a host, or a service provided by a host. These attacks prevent access to the attacked part of the network...

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Detecting low-profile probes and novel denial-of-service attacks

Accurate modeling of dual dipole and slot elements used with photomixers for coherent terahertz output power

June 1, 2001
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Journal Article
Author:
Sean M. Duffy
…
Published in:
IEEE Trans. Microw. Theory Tech., Vol. 49, No. 6, June 2001, pp. 1032-8.
Topic:
antennas
R&D area:
R&D group:

Summary

Accurate circuit models derived from electromagnetic simulations have been used to fabricate photomixer sources with optimized high-impedance antennas. Output powers on the order of 1 uW were measured for various designs spanning 0.6-2.7 THz. The improvement in output power ranged from 3 to 10 dB over more conventionally designed photomixers using broad-band log-spiral antennas. Measured data on single dipoles, twin dipoles, and twin slots are in good agreement with the characteristics predicted by the design simulations.
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Summary

Accurate circuit models derived from electromagnetic simulations have been used to fabricate photomixer sources with optimized high-impedance antennas. Output powers on the order of 1 uW were measured for various designs spanning 0.6-2.7 THz. The improvement in output power ranged from 3 to 10 dB over more conventionally designed photomixers...

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Accurate modeling of dual dipole and slot elements used with photomixers for coherent terahertz output power
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