Shallow water time‐series simulation using ray theory

1987 ◽  
Vol 81 (6) ◽  
pp. 1752-1761 ◽  
Author(s):  
Evan K. Westwood ◽  
C. T. Tindle
Keyword(s):  
Time Series ◽  
Shallow Water ◽  
Ray Theory ◽  
Time Series Simulation

scholarly journals Time series simulation in a sloping bottom environment using ray theory

1986 ◽  
Vol 80 (S1) ◽  
pp. S53-S53
Author(s):  
Evan K. Westwood ◽  
H. Hobaek ◽  
C. T. Tindle
Keyword(s):  
Time Series ◽  
Ray Theory ◽  
Time Series Simulation ◽  
Sloping Bottom

Tomographic inversion of measured cross-correlation functions of ocean noise in shallow water using ray theory

2016 ◽  
Vol 62 (4) ◽  
pp. 436-446 ◽  
Author(s):  
V. V. Goncharov ◽  
A. S. Shurup ◽  
O. A. Godin ◽  
N. A. Zabotin ◽  
A. I. Vedenev ◽  
...  
Keyword(s):  
Shallow Water ◽  
Correlation Functions ◽  
Cross Correlation ◽  
Ray Theory ◽  
Tomographic Inversion ◽  
Ocean Noise

scholarly journals Population structures among epiphytal foraminiferal communities, Nevis, West Indies

2008 ◽  
Vol 27 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Brent Wilson
Keyword(s):  
Time Series ◽  
Shallow Water ◽  
West Indies ◽  
Septic Tank ◽  
Amphistegina Gibbosa ◽  
Species Abundances ◽  
Population Structures ◽  
Logarithmic Series ◽  
One Year ◽  
Structure Investigations

Abstract. The taxocene of live epiphytal foraminifera was for one year monitored monthly on six phytal substrates in shallow water (<1 m) in two bays around Nevis, NE Caribbean Sea. Mosquito Bay was subject to a nutrient flux from a leaking septic tank. Long Haul Bay was comparatively undeveloped. SHE Community Structure Investigations (SHECSIs) revealed that the populations on five plants had logarithmic series distributions of species abundances, the slopes of lnS vs. lnE for these five time-series being within −1±0.3. In three time-series, they were within −1±0.05.Cluster analysis of twenty-five sediment samples in shallow water (<3 m) indicates that Nevis is largely surrounded by a single thanatacoenosis, for which SHECSI indicates a logarithmic series population structure. However, it is not possible to reconstruct perfectly the epiphytal population from the sediment thanatacoenosis. The thanatacoenosis included 40% allochthonous Amphistegina gibbosa, Archaias angulatus and Asterigerina carinata, washed in from offshore reefs, and few planorbulinids, although the latter dominates the biocoenosis on seagrass leaves in the backreef.

Time Series Simulations of Wide-Band Spectra for Fatigue Tests of Offshore Structures

1984 ◽  
Vol 106 (4) ◽  
pp. 466-470 ◽  
Author(s):  
N. K. Lin ◽  
W. H. Hartt
Keyword(s):  
Time Series ◽  
Fatigue Testing ◽  
Wide Band ◽  
Simulation Method ◽  
Offshore Structures ◽  
Fatigue Tests ◽  
Time Series Model ◽  
Long Time ◽  
Band Spectra ◽  
Time Series Simulation

A time-series simulation method, based on the principle of time series modeling for dynamic systems, is used to reproduce a wide-band stress history from a prescribed stress spectral model for fatigue testing of offshore structures. The optimization procedures and stability of the time series model for the prescribed spectrum are presented and discussed. The optimization procedures are developed on the basis of the Levison-Durbin algorithm, which usually produces a stable time series model if the order of the time series model is even. An example is presented to demonstrate the applicability of the proposed method to long-time, high-cycle fatigue testing.

scholarly journals A Depth-Bistatic Bottom Reverberation Model and Comparison with Data from an Active Triplet Towed Array Experiment

2020 ◽  
Vol 10 (9) ◽  
pp. 3080
Author(s):  
Youngcheol Jung ◽  
Woojae Seong ◽  
Keunhwa Lee ◽  
Seongil Kim
Keyword(s):  
Time Series ◽  
Deep Water ◽  
Water Environment ◽  
Ray Theory ◽  
Reverberation Time ◽  
Environment Model ◽  
Line Array ◽  
Model Predictions ◽  
Towed Array ◽  
Good Agreement

In this paper, a depth-bistatic bottom reverberation model that employs the ray theory is presented. The model can be applied to an active towed array in the ocean. The reverberation time series are modeled under the depth-bistatic assumption and their Doppler shift is calculated based on the actual source–receiver geometry. This model can handle N × 2D range-dependent bathymetry, the geometry of a triplet array, and the Doppler motion of the source, targets, and receiver. The model predictions are compared with the mid-frequency reverberation data measured by an active triplet towed array during August 2015 in the East Sea, Korea. These data are collected with a variable depth source at mid-frequency and the triplet line array in a deep-water environment. Model predictions of the beam time series and its spectrogram are in good agreement with the measurement. In particular, we discuss the effects of the source and receiver depths on the reverberation in deep water observed in both the measured and modeled results.

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