Time series simulation in shallow water using eigenrays with beam displacement

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.

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Time series simulation in a sloping bottom environment using ray theory

The Journal of the Acoustical Society of America ◽

10.1121/1.2023855 ◽

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

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

Journal of Energy Resources Technology ◽

10.1115/1.3231107 ◽

1984 ◽

Vol 106 (4) ◽

pp. 466-470 ◽

Cited By ~ 8

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.

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Probabilistic Quasi-Static Time Series Simulation for Distribution Network Planning Considering Multiple Uncertainties of PV and Load in the Presence of BESS

2020 52nd North American Power Symposium (NAPS) ◽

10.1109/naps50074.2021.9449825 ◽

2021 ◽

Author(s):

A. Parizad ◽

C. J. Hatziadoniu

Keyword(s):

Time Series ◽

Distribution Network ◽

Network Planning ◽

Distribution Network Planning ◽

Multiple Uncertainties ◽

Time Series Simulation

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THE ENERGY SPECTRA OF SURF WAVES ON A CORAL REEF

Coastal Engineering Proceedings ◽

10.9753/icce.v16.33 ◽

1978 ◽

Vol 1 (16) ◽

pp. 33 ◽

Cited By ~ 2

Author(s):

Theodore T. Lee ◽

Kerry P. Black

Keyword(s):

Time Series ◽

Coral Reef ◽

Probability Density Function ◽

Weibull Distribution ◽

Shallow Water ◽

Probability Density ◽

Density Function ◽

Linear Wave ◽

Gain Function ◽

Fourier Spectra

The transformation of waves crossing a coral reef in Hawaii including the probability density function of the wave heights and periods and the shape of the spectrum is discussed. The energy attenuation and the change of height and period statistics is examined using spectral analysis and the zero up-crossing procedure. Measurements of waves at seven points along a 1650 ft transect in depths from 1 to 3.5 ft on the reef and 35 ft offshore were made. The heights were tested for Rayleigh, truncated Rayleigh and Wei bull distributions. A symmetrical distribution presented by Longuet-Higgins (1975) and the Weibull distribution were compared to the wave period density function. In both cases the Weibull probability density function fitted with a high degree of correlation. Simple procedures to obtain Weibull coefficients are given. Fourier spectra were generated and contours of cumulative energy against each position on the reef show the shifting of energy from the peak as the waves move into shallow water. A design spectrum, with the shape of the Weibull distribution, is presented with procedures given to obtain the coefficients which govern the distribution peakedness. Normalized non-dimensional frequency and period spectra were recommended for engineering applications for both reef and offshore locations. A zero up-crossing spectrum (ZUS) constructed from the zero upcrossing heights and periods is defined and compared with the Fourier spectrum. Also discussed are the benefits and disadvantages of the ZUS, particularly for non-linear wave environments in shallow water. Both the ZUS and Fourier spectra are used to test the adequacy of formulae which estimate individual wave parameters. Cross spectra analysis was made to obtain gain function and squared coherency for time series between two adjacent positions. It was found that the squared coherency is close to unity near the peak frequency. This means that the output time series can be predicted from the input by applying the gain function. However, the squared coherency was extremely small for other frequencies above 0.25 H2.

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