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Institution

Defence Research Agency

About: Defence Research Agency is a based out in . It is known for research contribution in the topics: Synthetic aperture radar & Radar. The organization has 1211 authors who have published 1109 publications receiving 31542 citations.


Papers
More filters
Journal ArticleDOI
01 Apr 1993
TL;DR: An algorithm, the bootstrap filter, is proposed for implementing recursive Bayesian filters, represented as a set of random samples, which are updated and propagated by the algorithm.
Abstract: An algorithm, the bootstrap filter, is proposed for implementing recursive Bayesian filters. The required density of the state vector is represented as a set of random samples, which are updated and propagated by the algorithm. The method is not restricted by assumptions of linear- ity or Gaussian noise: it may be applied to any state transition or measurement model. A simula- tion example of the bearings only tracking problem is presented. This simulation includes schemes for improving the efficiency of the basic algorithm. For this example, the performance of the bootstrap filter is greatly superior to the standard extended Kalman filter.

8,018 citations

Journal ArticleDOI
TL;DR: A mechanism for depression of the plasma frequency into the far infrared or even GHz band is proposed: Periodic structures built of very thin wires dilute the average concentration of electrons and considerably enhance the effective electron mass through self-inductance.
Abstract: The plasmon is a well established collective excitation of metals in the visible and near UV, but at much lower frequencies dissipation destroys all trace of the plasmon and typical Drude behavior sets in. We propose a mechanism for depression of the plasma frequency into the far infrared or even GHz band: Periodic structures built of very thin wires dilute the average concentration of electrons and considerably enhance the effective electron mass through self-inductance. Computations replicate the key features and confirm our analytic theory. The new structure has novel properties not observed before in the GHz band, including some possible impact on superconducting properties.

3,954 citations

Journal ArticleDOI
TL;DR: In this paper, full 2D photonic bandgaps are demonstrated for all polarisations in structures with refractive index contrast as small as that of silica and air, and a new type of optical fiber based on these structures is proposed.
Abstract: Full 2-D photonic bandgaps are demonstrated for all polarisations in structures with refractive index contrast as small as that of silica and air. They occur for light propagating out of the transverse plane, with a longitudinal component of wave vector. A new type of optical fibre based on these structures is proposed.

472 citations

Journal ArticleDOI
TL;DR: In this paper, an improved method for the measurement of the ice water content (IWC) of cirrus cloud using a total water content probe is described, which resolves anomalies in the earlier measurements that were due to the assumption of saturation with respect to ice everywhere within cloud.
Abstract: This note describes an improved method for the measurement of the ice water content (IWC) of cirrus cloud using a total water content probe. A previous version of this technique assumed that the air in cloud-containing regions was saturated with respect to ice. This assumption has now been replaced with measurements of the water vapor content from a fast-response Lyman-α fluorescence water vapor sensor. The improved measurement of the vapor phase resolves anomalies in the earlier measurements that were due to the assumption of saturation with respect to ice everywhere within cloud. The comparison of IWC measurements made by this new method with those from a 2D optical array probe is greatly improved. The new measurements may now be used to provide much more stringent tests of the algorithms used for the derivation of crystal mass from measured size in 2D probe data.

400 citations


Authors

Showing all 1211 results

NameH-indexPapersCitations
Stephen M. Smith128501140104
Jonathan Knight8862537720
M. S. Skolnick7372822112
Alan Tennant7043316870
Richard J. Needs6935219528
Dan S. Henningson6636919038
John Rarity6543415562
Michael J. Uren442948408
Leigh T. Canham4216018268
A. G. Cullis4016111320
Richard A. Pethrick384106918
David S. Lee381138580
Neil Gordon3718137011
Pierfrancesco Lombardo363015018
Peter John Roberts31866679
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20221
20219
202018
201910
20189
201713