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LLGrid: supercomputer for sensor processing

April 15, 2013
  |
Book Chapter
Author:
Jeremy Kepner
…
Published in:
Chapter 24 in Contemporary High Performance Computing, April 2013.
Topic:
supercomputing
R&D area:
R&D group:

Summary

MIT Lincoln Laboratory is a federally funded research and development center that applies advanced technology to problems of national interest. Research and development activities focus on long-term technology development as well as rapid system prototyping and demonstration. A key part of this mission is to develop and deploy advanced sensor systems. Developing the algorithms for these systems requires interactive access to large scale computing and data storage. Deploying these systems requires that the computing and storage capabilities are transportable and energy efficient. The LLGrid system of supercomputers allows hundreds of researchers simultaneous interactive access to large amounts of processing and storage for development and testing of their sensor processing algorithms. The requirements of the LLGrid user base are as diverse as the sensors they are developing: sonar, radar, infrared, optical, hyperspectral, video, bio and cyber. However, there are two common elements: delivering large amounts of data interactively to many processors and high level user interfaces that require minimal user training. The LLGrid software stack provides these capabilities on dozens of LLGrid computing clusters across Lincoln Laboratory. LLGrid systems range from very small (a few nodes) to very large (40+ racks).
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Summary

MIT Lincoln Laboratory is a federally funded research and development center that applies advanced technology to problems of national interest. Research and development activities focus on long-term technology development as well as rapid system prototyping and demonstration. A key part of this mission is to develop and deploy advanced sensor...

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LLGrid: supercomputer for sensor processing

Architecture-independent dynamic information flow tracking

March 16, 2013
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Conference Paper
Author:
Ryan J. Whelan
…
Published in:
CC 2013: 22nd Int. Conf. on Compiler Construction, 16-24 March 2013, pp. 144-163.
Topic:
computer architecture
R&D area:
R&D group:

Summary

Dynamic information flow tracking is a well-known dynamic software analysis technique with a wide variety of applications that range from making systems more secure, to helping developers and analysts better understand the code that systems are executing. Traditionally, the fine-grained analysis capabilities that are desired for the class of these systems which operate at the binary level require tight coupling to a specific ISA. This places a heavy burden on developers of these systems since significant domain knowledge is required to support each ISA, and the ability to amortize the effort expended on one ISA implementation cannot be leveraged to support other ISAs. Further, the correctness of the system must carefully evaluated for each new ISA. In this paper, we present a general approach to information flow tracking that allows us to support multiple ISAs without mastering the intricate details of each ISA we support, and without extensive verification. Our approach leverages binary translation to an intermediate representation where we have developed detailed, architecture-neutral information flow models. To support advanced instructions that are typically implemented in C code in binary translators, we also present a combined static/dynamic analysis that allows us to accurately and automatically support these instructions. We demonstrate the utility of our system in three different application settings: enforcing information flow policies, classifying algorithms by information flow properties, and characterizing types of programs which may exhibit excessive information flow in an information flow tracking system.
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Summary

Dynamic information flow tracking is a well-known dynamic software analysis technique with a wide variety of applications that range from making systems more secure, to helping developers and analysts better understand the code that systems are executing. Traditionally, the fine-grained analysis capabilities that are desired for the class of these...

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Architecture-independent dynamic information flow tracking

Etching selectivity of indium tin oxide to photoresist in high density chlorine- and ethylene-containing plasmas

March 13, 2013
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Journal Article
Author:
Steven A. Vitale
…
Published in:
J. Vac. Sci. Technol. B, Microelectron. and Nanometer Structures, Vol. 31, No. 2, 13 March 2013, 021210.
Topic:
advanced materials
R&D area:
R&D group:

Summary

Etching of indium tin oxide (ITO) thin films in high density chlorine plasmas is studied, with the goal of increasing the etching selectivity to photoresist. The ITO etching rate increases with ethylene addition, but is not affected by BCl3 addition. ITO exhibits a threshold energy for ion etching, whereas the photoresist etches spontaneously in chlorine plasmas. The ITO:photoresist selectivity increases with BCl3 addition, ion bombardment energy, and C2H4 addition. It is proposed that the ITO etching rate is limited by desorption of InClx products, and that ethylene addition assists in scavenging oxygen from ITO leaving loosely bound In, which is more easily removed by physical sputtering.
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Summary

Etching of indium tin oxide (ITO) thin films in high density chlorine plasmas is studied, with the goal of increasing the etching selectivity to photoresist. The ITO etching rate increases with ethylene addition, but is not affected by BCl3 addition. ITO exhibits a threshold energy for ion etching, whereas the...

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Etching selectivity of indium tin oxide to photoresist in high density chlorine- and ethylene-containing plasmas

Reconfigurable RF systems using commercially available digital capacitor arrays

March 1, 2013
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Conference Paper
Author:
Noyan Kinayman
…
Published in:
38th Annual GOMACTech Conf., 11-14 March 2013.
Topic:
communications
R&D area:
R&D group:

Summary

Various RF circuit blocks implemented by using commercially available MEMS digital capacitor arrays are presented for reconfigurable RF systems. The designed circuit blocks are impedance-matching network, tunable bandpass filter, and VSWR sensor. The frequency range of the designed circuits is 0.4-4GHz. The MEMS digital capacitor arrays that are employed in the designs have built-in dc-to-dc voltage converter and serial interface significantly simplifying the control circuitry. The RF circuit blocks are suitable to low-cost, high-level of integration, thanks to the commercially available parts and standard RF packaging technologies.
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Summary

Various RF circuit blocks implemented by using commercially available MEMS digital capacitor arrays are presented for reconfigurable RF systems. The designed circuit blocks are impedance-matching network, tunable bandpass filter, and VSWR sensor. The frequency range of the designed circuits is 0.4-4GHz. The MEMS digital capacitor arrays that are employed in...

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Reconfigurable RF systems using commercially available digital capacitor arrays

Risk-based modeling to support NextGen concept assessment and validation

March 1, 2013
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Project Report
Author:
Eric P. Harkleroad
…
Published in:
MIT Lincoln Laboratory Report ATC-405
Topic:
modeling
R&D area:

Summary

This report provides a brief review of major risk-based modeling (RBM) approaches, with particular emphasis on how these tools can be applied during initial Next Generation Air Transportation System (NextGen) concept development and how their use can be validated. Effective safety analysis should play a role even during a new system's concept definition and development. Elements of NextGen are currently progressing through these early phases. NextGen will increasingly rely on integrating multiple systems and information together to enable improved efficiency, safety, and reduced environmental impact. Ensuring that such complex interconnected systems are developed to meet safety goals requires corresponding advances in RBM and safety assessment approaches. This report does not cover the more detailed safety analyses that must be applied to mature system concepts. Rather, the focus is on approaches for hazard identification, scoping, and coarse risk estimation for systems in the early conceptual development stage, when details on the design and operation of the system have yet to be resolved. Risk models applied is this constrained context cannot be expected to provide the same complete, quantitative results as they do for mature systems. Following a review of prior models, this report continues with recommendations for RBM development, application, validation, and coordination between NextGen efforts. Also, a discussion on safety and concept development is provided.
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Summary

This report provides a brief review of major risk-based modeling (RBM) approaches, with particular emphasis on how these tools can be applied during initial Next Generation Air Transportation System (NextGen) concept development and how their use can be validated. Effective safety analysis should play a role even during a new...

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Risk-based modeling to support NextGen concept assessment and validation

RECOG: Recognition and Exploration of Content Graphs

February 26, 2013
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Conference Paper
Author:
Kara B. Greenfield
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Published in:
Pacific Vision, 26 February - March 1, 2013.
Topic:
speaker recognition
R&D area:
R&D group:

Summary

We present RECOG (Recognition and Exploration of COntent Graphs), a system for visualizing and interacting with speaker content graphs constructed from large data sets of speech recordings. In a speaker content graph, nodes represent speech signals and edges represent speaker similarity. First, we describe a layout algorithm that optimizes content graphs for ease of navigability. We then present an interactive tool set that allows an end user to find and explore interesting occurrences in the corpus. We also present a tool set that allows a researcher to visualize the shortcomings of current content graph generation algorithms. RECOG's layout and toolsets were implemented as Gephi plugins [1].
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Summary

We present RECOG (Recognition and Exploration of COntent Graphs), a system for visualizing and interacting with speaker content graphs constructed from large data sets of speech recordings. In a speaker content graph, nodes represent speech signals and edges represent speaker similarity. First, we describe a layout algorithm that optimizes content...

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RECOG: Recognition and Exploration of Content Graphs

High-power arrays of quantum cascade laser master-oscillator power-amplifiers

February 25, 2013
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Journal Article
Author:
Patrick Rauter
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Published in:
Opt. Express, Vol. 21, No. 4, 25 February 2013, pp. 4518-4530.
Topic:
lasers
R&D area:
R&D group:

Summary

We report on multi-wavelength arrays of master-oscillator power-amplifier quantum cascade lasers operating at wavelengths between 9.2 and 9.8 um. All elements of the high-performance array feature longitudinal (spectral) as well as transverse single-mode emission at peak powers between 2.7 and 10 W at room temperature. The performance of two arrays that are based on different seed-section designs is thoroughly studied and compared. High output power and excellent beam quality render the arrays highly suitable for stand-off spectroscopy applications.
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Summary

We report on multi-wavelength arrays of master-oscillator power-amplifier quantum cascade lasers operating at wavelengths between 9.2 and 9.8 um. All elements of the high-performance array feature longitudinal (spectral) as well as transverse single-mode emission at peak powers between 2.7 and 10 W at room temperature. The performance of two arrays...

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High-power arrays of quantum cascade laser master-oscillator power-amplifiers

Wind information requirements for NextGen applications phase 1: 4D-trajectory based operations (4D-TBO)

February 20, 2013
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Project Report
Author:
Thomas G. Reynolds
…
Published in:
MIT Lincoln Laboratory Report ATC-399
Topic:
weather
R&D area:
R&D group:

Summary

Accurate wind information is required to support some of the key applications envisioned for future air traffic concepts. A Wind Information Analysis Framework has been developed to assess wind information needs for different applications. The framework is described and then applied in a Four-Dimensional Trajectory Based Operations (4D-TBO) application using simplified versions of the framework's elements to demonstrate its utility. Realistic ranges of wind information accuracy in terms of wind forecast and Flight Management System wind representation errors are studied. Their impacts on 4D-TBO performance in terms of Required Time of Arrival compliance and fuel burn are presented. Interpretations of the findings to give insights on wind information requirements are provided, together with an outline of the planned next phase of the study to further refine the outputs.
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Summary

Accurate wind information is required to support some of the key applications envisioned for future air traffic concepts. A Wind Information Analysis Framework has been developed to assess wind information needs for different applications. The framework is described and then applied in a Four-Dimensional Trajectory Based Operations (4D-TBO) application using...

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Wind information requirements for NextGen applications phase 1: 4D-trajectory based operations (4D-TBO)

Nonlinear bleaching, absorption, and scattering of 532-nm-irradiated plasmonic nanoparticles

February 7, 2013
  |
Journal Article
Author:
Vladimir Liberman
…
Published in:
J. Appl. Phys., Vol. 113. No. 5, 7 February 2013, 053107.
Topic:
lasers
R&D area:
R&D group:

Summary

Single-pulse irradiation of Au and Ag suspensions of nanospheres and nanodisks with 532-nm 4-ns pulses has identified complex optical nonlinearities while minimizing material damage. For all materials tested, we observe competition between saturable absorption (SA) and reverse SA (RSA), with RSA behavior dominating for intensities above ~50 MW/cm^2. Due to reduced laser damage in single-pulse experiments, the observed intrinsic nonlinear absorption coefficients are the highest reported to date for Au nanoparticles. We find size dependence to the nonlinear absorption enhancement for Au nanoparticles, peaking in magnitude for 80-nm nanospheres and falling off at larger sizes. The nonlinear absorption coefficients for Au and Ag spheres are comparable in magnitude. On the other hand, the nonlinear absorption for Ag disks, when corrected for volume fraction, is several times higher. These trends in nonlinear absorption are correlated to local electric field enhancement through quasi-static mean-field theory. Through variable size aperture measurements, we also separate nonlinear scattering from nonlinear absorption. For all materials tested, we find that nonlinear scattering is highly directional and that its magnitude is comparable to that of nonlinear absorption. These results indicate methods to improve the efficacy of plasmonic nanoparticles as optical limiters in pulsed laser systems.
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Summary

Single-pulse irradiation of Au and Ag suspensions of nanospheres and nanodisks with 532-nm 4-ns pulses has identified complex optical nonlinearities while minimizing material damage. For all materials tested, we observe competition between saturable absorption (SA) and reverse SA (RSA), with RSA behavior dominating for intensities above ~50 MW/cm^2. Due to...

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Nonlinear bleaching, absorption, and scattering of 532-nm-irradiated plasmonic nanoparticles

Development of adaptive liquid microlenses and microlens arrays

February 4, 2013
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Conference Paper
Author:
Shaun R. Berry
…
Published in:
SPIE Photonics West 2013: MOEMS-MEMS, 2-7 February 2013.
Topic:
microfluidics
R&D area:
R&D group:

Summary

We report on the development of sub-millimeter size adaptive liquid microlenses and microlens arrays using two immiscible liquids to form individual lenses. Microlenses and microlens arrays having aperture diameters as small as 50 microns were fabricated on a planar quartz substrate using patterned hydrophobic/hydrophilic regions. Liquid lenses were formed by a self-assembled oil dosing process that created well-defined lenses having a high fill factor. Variable focus was achieved by controlling the lens curvature through electrowetting. Greater than 70 degrees of contact angle change was achieved with less than 20 volts, which results in a large optical power dynamic range.
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Summary

We report on the development of sub-millimeter size adaptive liquid microlenses and microlens arrays using two immiscible liquids to form individual lenses. Microlenses and microlens arrays having aperture diameters as small as 50 microns were fabricated on a planar quartz substrate using patterned hydrophobic/hydrophilic regions. Liquid lenses were formed by...

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Development of adaptive liquid microlenses and microlens arrays
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