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Airport surface traffic management decision support - perspectives based on tower flight data manager prototype

May 20, 2013
  |
Project Report
Author:
Vineet Mehta
…
Published in:
MIT Lincoln Laboratory Report ATC-398
Topic:
decision support
R&D area:
R&D group:

Summary

This report describes accomplishments and insights gathererd during the development of decision support tools as part of the Terminal Flight Data Manager (TFDM) program. This work was performed by MIT Lincoln Laboratory and sponsored by the Federal Aviation Administration (FAA). The TFDM program integrated flight data, aircraft surveillance, information on weather and traffic flow constraints, and other data required to optimize airport conguration and arrival/departure management functions. The prototype has been evaluated in both human-in-the-loop simulations, and during operational tests at Dallas/Fort Worth (DFW) International Airport. In parallel, the Laboratory estimated future national operational benefits for TFDM decision support functions, using analysis and performance data gathered from major airports in the US. This analysis indicated that the greatest potential operational benefits would come from decision support tools that facilitate: i) managing runway queues and sequences, ii) tactical management of flight routes and times, impacted by weather and traffic constraints, and iii) managing airport configuration changes. Evaluation of TFDM prototype decision support functions in each of these areas provided valuable insights relative to the maturity of current capabilities and research needed to close performance gaps.
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Summary

This report describes accomplishments and insights gathererd during the development of decision support tools as part of the Terminal Flight Data Manager (TFDM) program. This work was performed by MIT Lincoln Laboratory and sponsored by the Federal Aviation Administration (FAA). The TFDM program integrated flight data, aircraft surveillance, information on...

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Airport surface traffic management decision support - perspectives based on tower flight data manager prototype

Interdependence of the electricity generation system and the natural gas system and implications for energy security

May 15, 2013
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Technical Report
Author:
Nicholas M. F. Judson
Published in:
MIT Lincoln Laboratory Report TR-1173
Topic:
energy systems
R&D area:
R&D group:

Summary

Concern about energy security on domestic Department of Defense installations has led to the possibility of using natural gas-fired electricity generators to provide power in the event of electric grid failures. The natural gas system in the United States is partly dependent on electricity for its ability to deliver natural gas from the well-head to the consumer, but it also uses natural gas from the system itself to fuel some of the drilling rigs, processing units, and pipeline compressors. The vulnerability of the system to a disruption in the national electricity supply network varies depending on the cause and breadth of the disruption and where in the country one is located relative to that disruption, as the interconnected nature of transmission pipelines, the penetration of electric motor-driven compressors and other equipment, and the availability of nearby gas production, import terminals, or storage varies. In general, the gas supply system is reliable for short-term, limited-area disruptions in the electricity supply, and firm delivery contracts for natural gas increase the likelihood of continued operation, but for disruptions that cover large sections of the electric grid encompassing areas from extraction wells to customers and which last longer than available gas in storage or transmission pipeline constraints from elsewhere, contractual force majeure limits will come into play rendering the firm delivery contracts void; operation of gas-fueled power generation systems that are not dual-fuel capable for longer than weeks to a few months (depending on time of year) will be unlikely. Several weather-related outages in recent years have provided limited case studies showing the system's resilience, but no long-term, widespread electricity grid failures have occurred.
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Summary

Concern about energy security on domestic Department of Defense installations has led to the possibility of using natural gas-fired electricity generators to provide power in the event of electric grid failures. The natural gas system in the United States is partly dependent on electricity for its ability to deliver natural...

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Interdependence of the electricity generation system and the natural gas system and implications for energy security

High-voltage GaN-on-silicon Schottky diodes

May 13, 2013
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Conference Paper
Author:
Timothy Boles
…
Published in:
CS ManTech 2013, 13-16 May 2013.
Topic:
electronics
R&D area:

Summary

M/A-COM Technology Solutions has continuing joint development efforts sponsored by the Department of Energy with MIT main campus and MIT Lincoln Laboratory to develop GaN-on-silicon two and three-terminal high-voltage/high current switching devices. The initial developmental goals were for a Schottky diode that has a reverse breakdown blocking voltage of >600 volts and is capable of handling 10 amperes of forward current. A comparison of the M/A-COM Technology Solutions lateral GaN Schottky diode on-resistance as a function of reverse breakdown voltage for a number of both lateral and vertical GaN Schottky diode geometries taken from the literature is presented. The substrates employed for all of these data points are either sapphire, SiC, silicon, and even one study which utilized single crystal GaN. Also included in this plot are theoretical limits for the basic materials typically used in GaN Schottky diode construction. It can be seen that the reverse breakdown results of approximately 1500 volts for M/A/-COM Technology Solutions lateral anode connected field GaN Schottky diodes on silicon substrates compare extremely favorably with the reported performance of the state-of-the-art devices, regardless of substrate material or design geometry.
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Summary

M/A-COM Technology Solutions has continuing joint development efforts sponsored by the Department of Energy with MIT main campus and MIT Lincoln Laboratory to develop GaN-on-silicon two and three-terminal high-voltage/high current switching devices. The initial developmental goals were for a Schottky diode that has a reverse breakdown blocking voltage of >600...

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High-voltage GaN-on-silicon Schottky diodes

Single-mode tapered quantum cascade lasers

May 6, 2013
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Journal Article
Author:
Patrick Rauter
…
Published in:
Appl. Phys. Lett., Vol. 102, No. 18, 6 May 2013.
Topic:
lasers
R&D area:
R&D group:

Summary

We demonstrate tapered quantum cascade lasers monolithically integrated with a distributed Bragg reflector acting as both a wavelength-selective back mirror and a transverse mode filter. Each of the 14 devices operates at a different wavelength between 9.2 and 9.7 um, where nine devices feature single-mode operation at peak powers between 0.3 and 1.6W at room temperature. High output power and excellent beam quality with peak brightness values up to 1.6MW cm^-2 sr^-1 render these two-terminal devices highly suitable for stand-off spectroscopy applications.
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Summary

We demonstrate tapered quantum cascade lasers monolithically integrated with a distributed Bragg reflector acting as both a wavelength-selective back mirror and a transverse mode filter. Each of the 14 devices operates at a different wavelength between 9.2 and 9.7 um, where nine devices feature single-mode operation at peak powers between...

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Single-mode tapered quantum cascade lasers

High power (>5 W) lambda ~9.6 um tapered quantum cascade lasers grown by OMVPE

May 1, 2013
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Conference Paper
Author:
Christine A. Wang
…
Published in:
J. Cryst. Growth, Vol. 370, May 2013, pp. 212-16.
Topic:
lasers
R&D area:
R&D group:

Summary

AlInAS/GaInAs superlattices (SLs) with barrier and well layers of various thicknesses were grown by organometallic vapor phase epitaxy to optimize growth of quantum cascade lasers (QCLs). High-resolution x-ray diffraction data of nominally lattice-matched SLs show a systematic shift toward more compressively strained SLs as the barrier/well layer thicknesses are decreased below about 10 nm. This shift is attributed to In surface segregation in both AlInAs and GaInAs. This shift is compensated for in the growth of ultra-thin layers in QCL structures. QCLs with tapered gain regions and emitting at 9.6 um are demonstrated with peak power as high as 5.3 W from one facet at 20 degrees C.
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Summary

AlInAS/GaInAs superlattices (SLs) with barrier and well layers of various thicknesses were grown by organometallic vapor phase epitaxy to optimize growth of quantum cascade lasers (QCLs). High-resolution x-ray diffraction data of nominally lattice-matched SLs show a systematic shift toward more compressively strained SLs as the barrier/well layer thicknesses are decreased...

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High power (>5 W) lambda ~9.6 um tapered quantum cascade lasers grown by OMVPE

High voltage GaN-on-silicon HEMT

May 1, 2013
  |
Journal Article
Author:
Timothy Boles
…
Published in:
Phys. Status Solidi C, Vol. 10, No. 5, May 2013, pp. 844-8.
Topic:
electronics
R&D area:

Summary

M/A-COM Technology Solutions has continued in the joint development efforts sponsored by the Department of Energy with MIT main campus amd MIT Lincoln Labs to develop GaN on silicon three terminal high voltage/high current HEMT switching devices. The first year developmental goals were for a three terminal structure that has a reverse breakdown characteristic of >1200 V and is capable of switching 10 amperes of current. An average three terminal breakown of 1322 V was achieved on a single finger 250 um GaN on silicon HEMT device utilizing a source connected field plate with a 4.5 um drain region overlap. An individual device breakdown on a single finger 250 um GaN on silicon HEMT device with a SCFP of >1630 V was measured at a current of 250 uA (1mA/mm) - One of the highest yet reported for GaN on silicon in the industry.
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Summary

M/A-COM Technology Solutions has continued in the joint development efforts sponsored by the Department of Energy with MIT main campus amd MIT Lincoln Labs to develop GaN on silicon three terminal high voltage/high current HEMT switching devices. The first year developmental goals were for a three terminal structure that has...

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High voltage GaN-on-silicon HEMT

Gadolinium oxide coated fully depleted silicon-on-insulator transistors for thermal neutron dosimetry

April 29, 2013
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Journal Article
Author:
Steven A. Vitale
…
Published in:
Nucl. Instrum. Methods Phys. Res. A, Accel., Vol. 721, 2013, pp. 45-9.
Topic:
detection systems
R&D area:
R&D group:

Summary

Fully depleted silicon-on-insulator transistors coated with gadolinium oxide are shown to be effective thermal neutron dosimeters. The theoretical neutron detection efficiency is calculated to be higher for Gd2O3 than for other practical converter materials. Proof-of-concept dosimeter devices were fabricated and tested during thermal neutron irradiation. The transistor current changes linearly with neutron dose, consistent with increasing positive charge in the SOI buried oxide layer generated by ionization from high energy 157Gd(n,γ)158Gd conversion electrons. The measured neutron sensitivity is approximately 1/6 the maximum theoretical value, possibly due to electron-hole recombination or conversion electron loss in interconnect wiring above the transistors.
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Summary

Fully depleted silicon-on-insulator transistors coated with gadolinium oxide are shown to be effective thermal neutron dosimeters. The theoretical neutron detection efficiency is calculated to be higher for Gd2O3 than for other practical converter materials. Proof-of-concept dosimeter devices were fabricated and tested during thermal neutron irradiation. The transistor current changes linearly...

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Gadolinium oxide coated fully depleted silicon-on-insulator transistors for thermal neutron dosimetry

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
  |
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
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