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An automated visibility detection algorithm utilizing camera imagery

Published in:
87Th AMS Annual Meeting, 14-18 January 2007.

Summary

The Federal Highway Administration (FHWA) has had a focused program to improve the integration of weather decision support systems into surface transportation operations since 1999. Clarus (Latin for clear) is the FHWA's most recent surface transportation weather initiative. The Clarus concept is to develop and demonstrate an integrated surface transportation weather observing, forecasting and data management system (Pisano, 2006a). As part of this effort, the FHWA is also promoting research into methods for applying new and existing sensor or probe data. These efforts include utilizing new in-vehicle sensor data that will be part of the vehicle infrastructure initiative (VII) (Pisano, 2006b), and finding innovative ways to use existing camera imagery. MIT Lincoln Laboratory (MIT/LL) was tasked to evaluate the usefulness of camera imagery for sensing ambient and road weather conditions and the feasibility for creating a portable visibility estimation algorithm. This paper gives a general background on the current utilization of camera imagery, including past and ongoing research of automated weather/condition algorithms. This is followed by a description of the MIT/LL camera test site, the analyses performed and the resultant prototype visibility estimation algorithm. In addition, the paper details application of the prototype algorithm to existing state DOT cameras in Utah. The final section discusses the future possibilities of camera-based weather and road condition algorithms.
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Summary

The Federal Highway Administration (FHWA) has had a focused program to improve the integration of weather decision support systems into surface transportation operations since 1999. Clarus (Latin for clear) is the FHWA's most recent surface transportation weather initiative. The Clarus concept is to develop and demonstrate an integrated surface transportation...

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Optimized growth of lattice-matched In(x)Al(1-x)N/GaN heterostructures by molecular beam epitaxy

Published in:
Appl. Phys. Lett., Vol. 90, No. 2, 8 January 2007, pp. 021922-1 - 021922-3.

Summary

The authors present a systematic study on the growth of the ternary compound In(x)Al(1-x)N by molecular beam epitaxy. This work concentrates on In mole fractions x around 0.17, as this composition is in-plane lattice matched to GaN. At a growth temperature of 540 degrees C, high quality material was obtained using a total metal to nitrogen flux ratio of ~1. Using these growth parameters, high quality GaN/InAlN superlattices were obtained without growth interruptions.
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Summary

The authors present a systematic study on the growth of the ternary compound In(x)Al(1-x)N by molecular beam epitaxy. This work concentrates on In mole fractions x around 0.17, as this composition is in-plane lattice matched to GaN. At a growth temperature of 540 degrees C, high quality material was obtained...

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Impact of photoacid generator leaching on optics photocontamination in 193-nm immersion lithography

Published in:
J. Micro/Nanolith. MEMS MOEMS, Vol. 6, No. 1, January-March 2007, pp. 013001-1 - 013001-7.

Summary

Leaching of resist components into water has been reported in several studies. Even low dissolution levels of photoacid generator (PAG) may lead to photocontamination of the last optical surface of the projection lens. To determine the impact of this phenomenon on optics lifetime, we initiate a set of controlled studies, where predetermined amounts of PAG are introduced into pure water and the results monitored quantitatively. The study identifies the complex, nonlinear paths leading to photocontamination of the optics. We also discover that spatial contamination patterns of the optics are strongly dependent on the flow geometry. Both bare SiO2 surfaces as well as coated CaF2 optics are studied. We find that for all surfaces, at concentrations typical of leached PAG, below 500 ppb, the in situ self-cleaning processes prevent contamination of the optics.
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Summary

Leaching of resist components into water has been reported in several studies. Even low dissolution levels of photoacid generator (PAG) may lead to photocontamination of the last optical surface of the projection lens. To determine the impact of this phenomenon on optics lifetime, we initiate a set of controlled studies...

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Automatic language recognition via spectral and token based approaches

Published in:
Chapter 41 in Springer Handbook of Speech Processing and Communication, 2007, pp. 811-24.

Summary

Automatic language recognition from speech consists of algorithms and techniques that model and classify the language being spoken. Current state-of-the-art language recognition systems fall into two broad categories: spectral- and token-sequence-based approaches. In this chapter, we describe algorithms for extracting features and models representing these types of language cues and systems for making recognition decisions using one or more of these language cues. A performance assessment of these systems is also provided, in terms of both accuracy and computation considerations, using the National Institute of Science and Technology (NIST) language recognition evaluation benchmarks.
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Summary

Automatic language recognition from speech consists of algorithms and techniques that model and classify the language being spoken. Current state-of-the-art language recognition systems fall into two broad categories: spectral- and token-sequence-based approaches. In this chapter, we describe algorithms for extracting features and models representing these types of language cues and...

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Practical attack graph generation for network defense

Published in:
Proc. of the 22nd Annual Computer Security Applications Conf., IEEE, 11-15 December 2006, pp.121-130.

Summary

Attack graphs are a valuable tool to network defenders, illustrating paths an attacker can use to gain access to a targeted network. Defenders can then focus their efforts on patching the vulnerabilities and configuration errors that allow the attackers the greatest amount of access. We have created a new type of attack graph, the multiple-prerequisite graph, that scales nearly linearly as the size of a typical network increases. We have built a prototype system using this graph type. The prototype uses readily available source data to automatically compute network reachability, classify vulnerabilities, build the graph, and recommend actions to improve network security. We have tested the prototype on an operational network with over 250 hosts, where it helped to discover a previously unknown configuration error. It has processed complex simulated networks with over 50,000 hosts in under four minutes.
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Summary

Attack graphs are a valuable tool to network defenders, illustrating paths an attacker can use to gain access to a targeted network. Defenders can then focus their efforts on patching the vulnerabilities and configuration errors that allow the attackers the greatest amount of access. We have created a new type...

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Experimental facility for measuring the impact of environmental noise and speaker variation on speech-to-speech translation devices

Published in:
Proc. IEEE Spoken Language Technology Workshop, 10-13 December 2006, pp. 250-253.

Summary

We describe the construction and use of a laboratory facility for testing the performance of speech-to-speech translation devices. Approximately 1500 English phrases from various military domains were recorded as spoken by each of 30 male and 12 female English speakers with variation in speaker accent, for a total of approximately 60,000 phrases available for experimentation. We describe an initial experiment using the facility which shows the impact of environmental noise and speaker variability on phrase recognition accuracy for two commercially available oneway speech-to-speech translation devices configured for English-to-Arabic.
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Summary

We describe the construction and use of a laboratory facility for testing the performance of speech-to-speech translation devices. Approximately 1500 English phrases from various military domains were recorded as spoken by each of 30 male and 12 female English speakers with variation in speaker accent, for a total of approximately...

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Microwave-induced cooling of a superconducting qubit

Published in:
Sci., Vol. 314, No. 5805, 8 December 2006, pp. 1589-1592.

Summary

We demonstrated microwave-induced cooling in a superconducting flux qubit. The thermal population in the first-excited state of the qubit is driven to a higher-excited state by way of a sideband transition. Subsequent relaxation into the ground state results in cooling. Effective temperatures as low as ≈3 millikelvin are achieved for bath temperatures of 30 to 400 millikelvin, a cooling factor between 10 and 100. This demonstration provides an analog to optical cooling of trapped ions and atoms and is generalizable to other solid-state quantum systems. Active cooling of qubits, applied to quantum information science, provides a means for qubit-state preparation with improved fidelity and for suppressing decoherence in multi-qubit systems.
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Summary

We demonstrated microwave-induced cooling in a superconducting flux qubit. The thermal population in the first-excited state of the qubit is driven to a higher-excited state by way of a sideband transition. Subsequent relaxation into the ground state results in cooling. Effective temperatures as low as ≈3 millikelvin are achieved for...

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Laser-induced fluorescence-cued, laser induced- breakdown spectroscopy biological-agent detection

Published in:
Appl. Opt., Vol. 45, No. 34, 1 December 2006, pp. 8806-8814.

Summary

Methods for accurately characterizing aerosols are required for detecting biological warfare agents. Currently, fluorescence-based biological agent sensors provide adequate detection sensitivity but suffer from high false-alarm rates. Combining single-particle fluorescence analysis with laser-induced breakdown spectroscopy (LIBS) provides additional discrimination and potentially reduces false-alarm rates. A transportable UV laser-induced fluorescence-cued LIBS test bed has been developed and used to evaluate the utility of LIBS for biological-agent detection. Analysis of these data indicates that LIBS adds discrimination capability to fluorescence-based biological-agent detectors. However, the data also show that LIBS signatures of biological agent simulants are affected by washing. This may limit the specificity of LIBS and narrow the scope of its applicability in biological-agent detection.
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Summary

Methods for accurately characterizing aerosols are required for detecting biological warfare agents. Currently, fluorescence-based biological agent sensors provide adequate detection sensitivity but suffer from high false-alarm rates. Combining single-particle fluorescence analysis with laser-induced breakdown spectroscopy (LIBS) provides additional discrimination and potentially reduces false-alarm rates. A transportable UV laser-induced fluorescence-cued LIBS...

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The security of OpenBSD: milk or wine?

Published in:
;login:, Vol. 31, No. 6, December 2006, pp. 26-32.

Summary

Purchase a fine wine, place it in a cellar, and wait a few years: The aging will have resulted in a delightful beverage, a product far better than the original. Purchase a gallon of milk, place it in a cellar, and wait a few years. You will be sorry. We know how the passing of time affects milk and wine, but how does aging affect the security of software? Many in the security research community have criticized software developers both for releasing software with so many vulnerabilities and for the lack of any apparent improvement in this software over time. However, critics have lacked quantitative evidence that applying effort over time will result in software with fewer vulnerabilities. In short, we don't know whether software security is destined to age like milk or has the potential to become wine. We thus investigated whether or not the rate at which vulnerabilities are reported in OpenBSD is decreasing over time.
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Summary

Purchase a fine wine, place it in a cellar, and wait a few years: The aging will have resulted in a delightful beverage, a product far better than the original. Purchase a gallon of milk, place it in a cellar, and wait a few years. You will be sorry. We...

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An efficient graph search decoder for phrase-based statistical machine translation

Published in:
Int. Workshop on Spoken Language Translation, 28 November 2006.

Summary

In this paper we describe an efficient implementation of a graph search algorithm for phrase-based statistical machine translation. Our goal was to create a decoder that could be used for both our research system and a real-time speech-to-speech machine translation demonstration system. The search algorithm is based on a Viterbi graph search with an A* heuristic. We were able to increase the speed of our decoder substantially through the use of on-the-fly beam pruning and other algorithmic enhancements. The decoder supports a variety of reordering constraints as well as arbitrary n-gram decoding. In addition, we have implemented disk based translation models and a messaging interface to communicate with other components for use in our real-time speech translation system.
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Summary

In this paper we describe an efficient implementation of a graph search algorithm for phrase-based statistical machine translation. Our goal was to create a decoder that could be used for both our research system and a real-time speech-to-speech machine translation demonstration system. The search algorithm is based on a Viterbi...

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