Results 61 to 70 of about 60,436 (303)

Bubble density gradient with laser detection: A wake-homing scheme for supercavitating vehicles

Advances in Mechanical Engineering, 2018
The poor mobility and complex target motion estimation are the two main challenges in the anti-ship attack missions of high-speed guided missiles. In this study, a new wake-homing scheme of supercavitating vehicles is proposed using the gradient wake ...
Jia Song, Likun Bian, Erfu Yang, Dongjing Su   +3 more
doaj   +1 more source

High-Frequency Volume and Boundary Acoustic Backscatter Fluctuations in Shallow Water [PDF]

, 2003
Volume and boundary acoustic backscatter envelope fluctuations are characterized from data collected by the Toroidal Volume Search Sonar (TVSS), a 68 kHz cylindrical array capable of 360° multibeam imaging in the vertical plane perpendicular to its axis.
de Moustier, Christian, Gallaudet, Timothy C   +1 more
core   +2 more sources

Tuning Detection of Ship Wakes by Detectability Modelling

The appearance and detectability of ship wakes in SAR imagery has been investigated for decades. Various wake components have been identified in the complex appearance of wake signatures. Wake signatures in SAR imagery can also be exploited for indirect ship detection if ship signatures are weak or absent.
Tings, Björn, Yang, Yi-Jie, Schnupfhagn, Christoph, Jacobsen, Sven   +3 more
openaire   +2 more sources

Executive Function and Entrepreneurial Opportunity Exploitation Under Risk and Uncertainty

Strategic Change, EarlyView.
ABSTRACT This study examines how executive functions shape entrepreneurial opportunity exploitation under different knowledge environments. Drawing on Knight's distinction between risk and uncertainty, we conducted a vignette experiment with 200 working adults.
Ipek Koparan, Gorkem Aksaray, Tatiana Manolova, Linda Edelman   +3 more
wiley   +1 more source

Extension of Ship Wake Detectability Model for Non-Linear Influences of Parameters Using Satellite Based X-Band Synthetic Aperture Radar

Remote Sensing, 2019
The physics of the imaging mechanism underlying the emergence of ship wakes in Synthetic Aperture Radar (SAR) images has been studied in the past by many researchers providing a well-understood theory.
Björn Tings, Andrey Pleskachevsky, Domenico Velotto, Sven Jacobsen   +3 more
doaj   +1 more source

Wake Features of Moving Submerged Bodies and Motion State Inversion of Submarines

IEEE Access, 2020
The interaction between a moving submerged body and a homogeneous/stratified fluid generates a Bernoulli hump, a Kelvin wake, and an internal wake on the water surface. The height distribution of wakes is directly related to the location and motion state
Fuduo Xue, Weiqi Jin, Su Qiu, Jie Yang
doaj   +1 more source

Numerical Insights Into the Resistance Reduction Mechanisms of Forward Tapered Transoms in High‐Speed Catamaran: A Computational Fluid Dynamics‐Based Study

International Journal of Mechanical System Dynamics, EarlyView.
ABSTRACT This study investigates the hydrodynamic influence of forward transom tapering on a displacement catamaran hull using computational fluid dynamics (CFD) simulations. Five taper configurations ranging from a vertical transom base design to a fully tapered stern (1.00B) were evaluated over a wide Froude number range (Fr = .3 to 1.0).
Chalermkiat Nuchturee, Chairat Napasaksri, Ramil Kesvarakul, Sarawuth Srinakaew   +3 more
wiley   +1 more source

Wake Homing Torpedo Guidance Using a Hierarchical Deep Reinforcement Learning Framework

IEEE Access
This paper proposes a novel Hierarchical Deep Reinforcement Learning (HRL) framework for wake homing torpedo guidance, applying the Discrete Event System Specification (DEVS) formalism to design high-level policies and reward shaping functions.
Kunchul Hwang, Jinwhan Kim
doaj   +1 more source

The Cerenkov effect revisited: from swimming ducks to zero modes in gravitational analogs

, 2012
We present an interdisciplinary review of the generalized Cerenkov emission of radiation from uniformly moving sources in the different contexts of classical electromagnetism, superfluid hydrodynamics, and classical hydrodynamics.
A. Amo, A. Amo, A. Chepelianskii, A. Phillips, A. Recati, A.J. Leggett, C. Ciuti, C. Cohen-Tannoudji, C. Luo, C. Mayoral, C.-S. Yih, C.-S. Yih, C.C. Mei, D. Budker, D. Pines, D. Sanvitto, D.C. Roberts, D.H. Auston, E.H. Lock, F. Belgiorno, G. Afanasiev, G. Jannes, G. Nardin, G. Rousseaux, G. Rousseaux, G.B. Whitham, G.E. Astrakharchik, G.W. Rayfield, I. Carusotto, I. Carusotto, I. Carusotto, I. Carusotto, I. Frank, I. Tamm, I.M. Frank, J. Fernández-Rossier, J. Lighthill, J. Macher, J. Macher, J. Voise, J.V. Jelley, J.W.M. Bush, L. Pitaevskii, L.D. Landau, L.V. Hau, M. Merrer Le, M.M. Kash, N. Pavloff, O. Darrigol, O. Darrigol, P. Leboeuf, P.A. Cherenkov, R. Balbinot, R. Houdré, R.M. Sorensen, S. Inouye, S. Vavilov, S. Weinfurtner, S. Xi, T. Freixanet, T. Frisch, T. Neely, T. Soomere, T. Torsvik, T.E. Stevens, V. Vlaminck, W. Langbein, W.G. Unruh, X.-N. Chen, X.-N. Chen, X.-N. Chen, Y. Pomeau, Y.B. Bazaliy, Yu.G. Gladush, É. Raphaël   +74 more
core   +1 more source

Study of the Far Wake of a Large Ship [PDF]

, 2011
A large dataset of high-resolution photographic images of far wakes of a volunteer observing ship (Royal Caribbean’s Explorer of the Seas) has been acquired under various meteorological conditions and ship operation modes.
Gilman, M., Graber, H., Soloviev, Alexander   +2 more
core   +2 more sources