Results 261 to 270 of about 769,052 (322)

Acoustic propagation through surface ship wakes

The Journal of the Acoustical Society of America, 2001
To predict acoustic propagation through a ship wake, an understanding is required of the physical properties (void fraction, spatial and temporal variation of the bubble structure, oceanic ambient dynamics, for example) of the wake, as well as an acoustic propagation model capable of handling the changes in these properties.
R. Lee Culver, Xiao Di, Brian Rapids, Steven Lutz, David Bradley   +4 more
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Viscosity, Wake, and Ship Waves

Journal of Ship Research, 1970
In this paper a theory of the effect of viscosity on ship waves is presented. It is shown that the wake affects the singularities kinematically equivalent to the hull and generates waves which modify the resulting wave pattern. The theory may explain why the estimate of the viscous resistance obtained by means of a wake survey and the estimate of the ...
openaire   +1 more source

In the Black Ships’ Wake

Pacific Historical Review
This paper focuses on the micro-actors—merchants, whalers, and would-be diplomatic representatives—who followed in the black ships’ wake in anticipation of opportunities at the newly opened treaty port of Hakodate. Examining the backgrounds, connections, and activities of these actors, we show that American commercial activity in Japan contrasted with ...
Steven Ivings, Rashaad Eshack
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Ship wakes in radar imagery

International Journal of Remote Sensing, 1997
In 1989 an experiment in Loch Linnhe, Scotland, was conducted to improve the understanding of radar images of internal-wave wakes generated by ships. During the experiment a multi-frequency synthetic-aperture radar (SAR) image containing several bright narrow V-shaped wakes was obtained during a period of low wind speed.
openaire   +1 more source

A Polarimetric Extension of Low-Rank Plus Sparse Decomposition and Radon Transform for Ship Wake Detection in Synthetic Aperture Radar Images

IEEE Geoscience and Remote Sensing Letters, 2019
In past research, the problem of obtaining stable motion estimation of maritime targets in sea clutter making wake structure detection and reconnaissance difficult has been tackled.
Filippo Biondi
semanticscholar   +1 more source

A New Automatic Ship Wake Detection for Sentinel-1 Imagery

IEEE International Geoscience and Remote Sensing Symposium, 2020
The paper presents an automatic algorithm tackling the problem of ship detection in situations where the ship signature itself is not visible. At this purpose, the algorithm proposed uses a combination of image processing techniques in order to identify ...
Elena Grosso, R. Guida
semanticscholar   +1 more source

Ship wakes detection in SAR images

Proceedings 7th International Conference on Signal Processing, 2004. Proceedings. ICSP '04. 2004., 2005
Detecting ship wakes from spaceborne SAR images is significant. But it is particularly difficult, especially detecting-thin line features. Because those features are not only affected by speckle but also affected by various other factors and the image resolution is often coarser than the wide of the corresponding objects. In this paper, an algorithm is
null Zhu Weigang, null Wei Hua, null Jia Xin, null Zhou Yinqing   +3 more
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Ship Wake Detection in X-band SAR Images Using Sparse GMC Regularization

IEEE International Conference on Acoustics, Speech, and Signal Processing, 2019
Ship wakes have crucial importance in the analysis of SAR images of the sea surface due to the information they carry about vessels. Since ship wakes mostly appear as lines in SAR images, line detection methods have been widely used for their ...
Oktay Karakus, A. Achim
semanticscholar   +1 more source

Ship-Wake Scattering Calculations

2002
Abstract : The low-grazing-angle electromagnetic backscattering from small breaking water waves has been analyzed using computational electromagnetics (CEM) techniques. A new approach based on the multilevel fast multipole algorithm was implemented for 3-D surface crest scattering to supplement existing 2-D techniques.
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Numerical simulation on ship bubbly wake

Journal of Marine Science and Application, 2011
Based on a volume of fluid two-phase model imbedded in the general computational fluid dynamics code FLUENT6.3.26, the viscous flow with free surface around a model-scaled KRISO container ship (KCS) was first numerically simulated. Then with a rigid-lid-free-surface method, the underwater flow field was computed based on the mixture multiphase model to
Huiping Fu, Pengcheng Wan
openaire   +1 more source