Recent Advances in the Analysis of SAR Data of the Polar Oceans

1998 ◽  
pp. 3-8 ◽  
Author(s):  
C. Tsatsoulis ◽  
R. Kwok
Keyword(s):  
Recent Advances ◽  
Polar Oceans ◽  
Sar Data

scholarly journals Lead Detection in Polar Oceans—A Comparison of Different Classification Methods for Cryosat-2 SAR Data

2018 ◽  
Vol 10 (8) ◽  
pp. 1190 ◽  
Author(s):  
Denise Dettmering ◽  
Alan Wynne ◽  
Felix Müller ◽  
Marcello Passaro ◽  
Florian Seitz
Keyword(s):  
Unsupervised Classification ◽  
Detection Algorithm ◽  
Classification Method ◽  
Correct Identification ◽  
Polar Regions ◽  
Classification Methods ◽  
Lead Detection ◽  
Radar Echoes ◽  
Polar Oceans ◽  
Sar Data

In polar regions, sea-ice hinders the precise observation of Sea Surface Heights (SSH) by satellite altimetry. In order to derive reliable heights for the openings within the ice, two steps have to be fulfilled: (1) the correct identification of water (e.g., in leads or polynias), a process known as lead classification; and (2) dedicated retracking algorithms to extract the ranges from the radar echoes. This study focuses on the first point and aims at identifying the best available lead classification method for Cryosat-2 SAR data. Four different altimeter lead classification methods are compared and assessed with respect to very high resolution airborne imagery. These methods are the maximum power classifier; multi-parameter classification method primarily based on pulse peakiness; multi-observation analysis of stack peakiness; and an unsupervised classification method. The unsupervised classification method with 25 clusters consistently performs best with an overall accuracy of 97%. Furthermore, this method does not require any knowledge of specific ice characteristics within the study area and is therefore the recommended lead detection algorithm for Cryosat-2 SAR in polar oceans.

Analysis of SAR Data of the Polar Oceans

1998 ◽  
Author(s):  
Costas Tsatsoulis ◽  
Ronald Kwok
Keyword(s):  
Polar Oceans ◽  
Sar Data

Recent Advances in High Dispersion Spectroscopy of Globular Cluster Stars

1988 ◽  
Vol 132 ◽  
pp. 525-530
Author(s):  
Raffaele G. Gratton
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
High Dispersion ◽  
Photographic Material ◽  
Recent Advances ◽  
Metal Abundances ◽  
Ccd Detectors ◽  
Major Progress

The use CCD detectors has allowed a major progress in abundance derivations for globular cluster stars in the last years. Abundances deduced from high dispersion spectra now correlates well with other abundance indicators. I discuss some problems concerning the derivation of accurate metal abundances for globular clusters using high dispersion spectra from both the old photographic and the most recent CCD data. The discrepant low abundances found by Cohen (1980), from photographic material for M71 giants, are found to be due to the use of too high microturbulences.

Chelation-assisted transition metal-catalysed C–H chalcogenylations

2020 ◽  
Vol 7 (8) ◽  
pp. 1022-1060 ◽  
Author(s):  
Wenbo Ma ◽  
Nikolaos Kaplaneris ◽  
Xinyue Fang ◽  
Linghui Gu ◽  
Ruhuai Mei ◽  
...  
Keyword(s):  
Transition Metal ◽  
Recent Advances ◽  
Site Selectivity ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

This review summarizes recent advances in C–S and C–Se formations via transition metal-catalyzed C–H functionalization utilizing directing groups to control the site-selectivity.

Nucleosome dynamics

2006 ◽  
Vol 73 ◽  
pp. 109-119 ◽  
Author(s):  
Chris Stockdale ◽  
Michael Bruno ◽  
Helder Ferreira ◽  
Elisa Garcia-Wilson ◽  
Nicola Wiechens ◽  
...  
Keyword(s):  
High Resolution ◽  
Chromatin Structure ◽  
Current Knowledge ◽  
Dynamic Properties ◽  
Structure And Dynamics ◽  
Nucleosome Dynamics ◽  
Sharp Focus ◽  
Recent Advances ◽  
Insight Into ◽  
Chromatin Structure And Dynamics

In the 30 years since the discovery of the nucleosome, our picture of it has come into sharp focus. The recent high-resolution structures have provided a wealth of insight into the function of the nucleosome, but they are inherently static. Our current knowledge of how nucleosomes can be reconfigured dynamically is at a much earlier stage. Here, recent advances in the understanding of chromatin structure and dynamics are highlighted. The ways in which different modes of nucleosome reconfiguration are likely to influence each other are discussed, and some of the factors likely to regulate the dynamic properties of nucleosomes are considered.

Recent Advances in the Treatment of Pulmonary Tuberculosis

1950 ◽  
Vol 34 (5) ◽  
pp. 1363-1380
Author(s):  
Theodore L. Badger ◽  
William E. Patton
Keyword(s):  
Pulmonary Tuberculosis ◽  
Recent Advances

Recent Advances in Thyroid Imaging

1990 ◽  
Vol 23 (2) ◽  
pp. 251-270
Author(s):  
Martin P. Sandler, MD ◽  
James A. Patton ◽  
Robert H. Ossoff
Keyword(s):  
Thyroid Imaging ◽  
Recent Advances
Sign in / Sign up

Export Citation Format

Share Document