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Institution

Raytheon

CompanyWaltham, Massachusetts, United States
About: Raytheon is a company organization based out in Waltham, Massachusetts, United States. It is known for research contribution in the topics: Signal & Antenna (radio). The organization has 15290 authors who have published 18973 publications receiving 300052 citations.
Topics: Signal, Antenna (radio), Radar, Turbine, Amplifier


Papers
More filters
Journal ArticleDOI
TL;DR: A new correlation filter design method is presented that allows one to optimally tradeoff among potentially conflicting correlation output performance criteria while achieving desired correlation peak value behavior in response to in-plane rotation of input images.
Abstract: Correlation methods are becoming increasingly attractive tools for image recognition and location. This renewed interest in correlation methods is spurred by the availability of high-speed image processors and the emergence of correlation filter designs that can optimize relevant figures of merit. In this paper, a new correlation filter design method is presented that allows one to optimally tradeoff among potentially conflicting correlation output performance criteria while achieving desired correlation peak value behavior in response to in-plane rotation of input images. Such controlled in-plane rotation response is useful in image analysis and pattern recognition applications where the sensor follows a pre-arranged trajectory while imaging an object. Since this new correlation filter design is based on circular harmonic function (CHF) theory, we refer to the resulting filters as optimal tradeoff circular harmonic function (OTCHF) filters. Underlying theory, OTCHF filter design method, and illustrative numerical results are presented.

79 citations

Journal ArticleDOI
J. Pappis1, S. L. Blum1
TL;DR: In this article, the authors describe pyrolytic graphite as a vapor-deposited form of carbon which is characterized by strong anisotropic properties, which is caused by the tendency of individual crystallites to align themselves in such a way that their c axes are perpendicular to the surface of deposition.
Abstract: Pyrolytic graphite is a vapor-deposited form of carbon which is characterized by strong anisotropic properties. The anisotropy is caused by the tendency of the individual crystallites to align themselves in such a way that their c axes are perpendicular to the surface of deposition. The Individual crystallites are composed of parallel graphitic layers which are randomly oriented with respect to the c axis. The ultimate strength of pyrolytic graphite in tension, bending, and compression has been found to increase considerably with increasing test temperatures. Other properties such as thermal conductivity and electrical resistivity give extremely high and low conduction parallel and perpendicular to the basal planes, respectively, in addition to varying considerably with increasing test temperatures. Properties are also influenced by the as-deposited microstructure and by the amount of graphitization to which the material has been subjected. The properties and possible uses of this unique material are presented, discussed, and compared with the properties of other high-temperature materials.

79 citations

Patent
John R. Staley1
23 Dec 2004
TL;DR: In this article, the authors present a system that allows the user to adjust the sight orientation of a firearm in order to hit a target with a munition, in response to a lack of user activity for a selected time interval.
Abstract: A device can be supported on a weapon, and has a range portion that specifies a range to a target, a sensor portion that provides sensor information representing an orientation of the device; and a sight that facilitates weapon orientation in preparation to fire the munition. The device has an electronic control portion responsive to sensor information from the sensor portion and a range from the range portion for calculating how to hit a target with a munition, and for causing the sight to present a visual indication of how to orient the weapon so that the munition will hit the target, the electronic control portion terminating the presentation of the visual indication by the sight in response to a lack of user activity for a selected time interval during the presentation of the visual indication.

79 citations

Journal ArticleDOI
TL;DR: In this paper, an analysis of the star formation history (SFH) of a field near the half-light radius in the Local Group dwarf irregular galaxy IC 1613 based on deep Hubble Space Telescope Advanced Camera for Surveys imaging is presented.
Abstract: We present an analysis of the star formation history (SFH) of a field near the half-light radius in the Local Group dwarf irregular galaxy IC 1613 based on deep Hubble Space Telescope Advanced Camera for Surveys imaging. Our observations reach the oldest main sequence turn-off, allowing a time resolution at the oldest ages of ~1 Gyr. Our analysis shows that the SFH of the observed field in IC 1613 is consistent with being constant over the entire lifetime of the galaxy. These observations rule out an early dominant episode of star formation in IC 1613. We compare the SFH of IC 1613 with expectations from cosmological models. Since most of the mass is in place at early times for low-mass halos, a naive expectation is that most of the star formation should have taken place at early times. Models in which star formation follows mass accretion result in too many stars formed early and gas mass fractions that are too low today (the "over-cooling problem"). The depth of the present photometry of IC 1613 shows that, at a resolution of ~1 Gyr, the star formation rate is consistent with being constant, at even the earliest times, which is difficult to achieve in models where star formation follows mass assembly. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program 10505.

79 citations

Journal ArticleDOI
TL;DR: In this paper, a predictive model for the resonant frequencies of rectangular microstrip antennas with flush and spaced superstrates is presented for the integration of microstrip antenna beneath plastic covers or protective dielectric superstrate in portable wireless equipment.
Abstract: This paper presents a predictive model for the resonant frequencies of rectangular microstrip antennas with flush and spaced superstrates This closed-form model is suitable for CAD and is directly applicable for the integration of microstrip antennas beneath plastic covers or protective dielectric superstrates in portable wireless equipment The model utilizes conformal mapping and the concept of equivalent capacitance to determine the effective permittivity of a covered microstrip structure A comparison between calculated and measured resonant frequencies demonstrates that the model provides less than 1% errors for structures with low relative permittivities (/spl epsi//sub r/<3) and slightly higher errors for structures that contain higher permittivity materials Generally, the model predicts the resonant frequency of a spaced superstrate structure as accurately as possible within the tolerance range of the structure's electrical and physical parameters

79 citations


Authors

Showing all 15293 results

NameH-indexPapersCitations
Peter J. Kahrilas10958646064
Edward J. Wollack104732102070
Duong Nguyen9867447332
Miroslav Krstic9595542886
Steven L. Suib8986234189
Gabriel M. Rebeiz8780632443
Charles W. Engelbracht8321028137
Paul A. Grayburn7739726880
Eric J. Huang7220122172
Thomas F. Eck7215032965
David M. Margolis7022717314
David W. T. Griffith6528814232
Gerhard Klimeck6568518447
Nickolay A. Krotkov6321911250
Olaf Stüve6329014268
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20232
20228
2021265
2020655
2019579
2018457