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Journal articles on the topic 'Directional wave spectrum estimation'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Hashimoto, Noriaki, and Koji Konbune. "DIRECTIONAL SPECTRUM ESTIMATION FROM A BAYESIAN APPROACH." Coastal Engineering Proceedings 1, no. 21 (1988): 4. http://dx.doi.org/10.9753/icce.v21.4.

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A new directional spectral estimation method using a Bayesian approach is proposed. The proposed method is examined for numerical simulation data, and the validity of the method is discussed. Some examples of the directional spectra estimated from field observation data attained at an offshore oil rig utilizing seven wave probes are also shown in this report. The major conclusions of the report are : (1) The proposed method can be applied for more than four arbitrarily mixed instrument array measurements. (2) It has a higher resolution power than other existing methods for estimating direction

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2

Tannuri, Eduardo A., Pedro C. Mello, Joel S. Sales, Alexandre N. Simos, and Vinicius L. F. Matos. "Estimation of directional wave spectrum using a wave-probe array." Marine Systems & Ocean Technology 3, no. 2 (2007): 123–29. http://dx.doi.org/10.1007/bf03449221.

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3

Ewans, K. C., E. M. Bitner-Gregersen, and C. Guedes Soares. "Estimation of Wind-Sea and Swell Components in a Bimodal Sea State." Journal of Offshore Mechanics and Arctic Engineering 128, no. 4 (2004): 265–70. http://dx.doi.org/10.1115/1.2166655.

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Methods for separating the spectral components and describing bimodal wave spectra are evaluated with reference to wave spectra from directional wave measurements made at the Maui location off the west coast of New Zealand. Two methods involve partitioning bimodal wave spectra into wind-sea and swell components and then fitting a spectral function to each component, while the third assigns an average spectral shape based on the integrated spectral parameters. The partitioning methods involve separating the wave spectrum into two frequency bands: a low-frequency peak, the swell component, and a

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4

Lukijanto, Lukijanto, Noriaki Hashimoto, and Masaru Yamashiro. "VERIFICATION OF A MODIFIED BAYESIAN METHOD FOR ESTIMATING DIRECTIONAL WAVE SPECTRA FROM HF RADAR." Coastal Engineering Proceedings 1, no. 32 (2011): 65. http://dx.doi.org/10.9753/icce.v32.waves.65.

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A Modified Bayesian Method (MBM) for estimating directional wave spectra from Doppler spectra obtained by HF radar is examined using field data which were employed in the verification of Bayesian Method (BM). Applicability, validity and accuracy of the MBM are demonstrated compared with the directional wave spectra estimated by BM and observed by buoy acquired from the reliable field data obtained from Surface Current and Wave Variability Experiments (SCAWVEX) project. The necessary conditions of the Doppler spectral components to be used to estimate a reliable directional spectrum are corresp

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5

KOJIMA, Shoichiro, Noriaki HASHIMOTO, and Masaki SAWAMOTO. "Estimation of Directional Wave Spectrum from EERS1-SAR Image." Journal of the Japan society of photogrammetry and remote sensing 43, no. 3 (2004): 4–12. http://dx.doi.org/10.4287/jsprs.43.3_4.

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6

YOKOGAWA, Youtarou, Takashi IZUMIYA, and Kunihiko ISHIBASHI. "CHARACTERISTICS OF DIRECTIONAL WAVE SPECTRA ESTIMATED BY A HIGH PRECISION ESTIMATION METHOD OF DIRECTIONAL WAVE SPECTRUM." Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering) 69, no. 2 (2013): I_646—I_651. http://dx.doi.org/10.2208/jscejoe.69.i_646.

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7

MITSUI, Masao, Noriaki HASHIMOTO, Hiroyasu KAWAI, Masaki YOKOTA, and Yasushi KITAMURA. "Accuracy Improvement of Directional Spectrum Estimation with Upgraded Submerged Doppler Type Directional Wave Meter." Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 66, no. 1 (2010): 1446–50. http://dx.doi.org/10.2208/kaigan.66.1446.

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8

Pascoal, Ricardo, and C. Guedes Soares. "Kalman filtering of vessel motions for ocean wave directional spectrum estimation." Ocean Engineering 36, no. 6-7 (2009): 477–88. http://dx.doi.org/10.1016/j.oceaneng.2009.01.013.

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9

IWASAKI, Hiroshi, Masaki YOKOTA, Noriaki HASHIMOTO, Masao MITSUI, and Hiroyasu KAWAI. "ESTIMATION ACCURACY OF DIRECTIONAL SPECTRUM BASED ON THE SEVERAL COMBINATION OF WAVE SIGNAL WITH DOPPLER TYPE DIRECTIONAL WAVE METER." Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering) 67, no. 2 (2011): I_955—I_960. http://dx.doi.org/10.2208/jscejoe.67.i_955.

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10

KUWASHIMA, Susumu. "Estimation of the Directional Wave Spectrum from Ship Encounter Frequency Spectra-II." Journal of Japan Institute of Navigation 78 (1988): 23–33. http://dx.doi.org/10.9749/jin.78.23.

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11

Waseda, T., K. In, K. Kiyomatsu, H. Tamura, Y. Miyazawa, and K. Iyama. "Predicting freakish sea state with an operational third generation wave model." Natural Hazards and Earth System Sciences Discussions 1, no. 6 (2013): 6257–89. http://dx.doi.org/10.5194/nhessd-1-6257-2013.

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Abstract. Understanding of freak wave generation mechanism has advanced and the community has reached to a consensus that spectral geometry plays an important role. Numerous marine accident cases were studied and revealed that the narrowing of the directional spectrum is a good indicator of dangerous sea. However, the estimation of the directional spectrum depends on the performance of the third generation wave model. In this work, a well-studied marine accident case in Japan in 1980 (Onomichi–Maru incident) is revisited and the sea states are hind-casted using both the DIA and SRIAM nonlinear

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12

Waseda, T., K. In, K. Kiyomatsu, H. Tamura, Y. Miyazawa, and K. Iyama. "Predicting freakish sea state with an operational third-generation wave model." Natural Hazards and Earth System Sciences 14, no. 4 (2014): 945–57. http://dx.doi.org/10.5194/nhess-14-945-2014.

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Abstract. The understanding of freak wave generation mechanisms has advanced and the community has reached a consensus that spectral geometry plays an important role. Numerous marine accident cases were studied and revealed that the narrowing of the directional spectrum is a good indicator of dangerous sea. However, the estimation of the directional spectrum depends on the performance of the third-generation wave model. In this work, a well-studied marine accident case in Japan in 1980 (Onomichi-Maru incident) is revisited and the sea states are hindcasted using both the DIA (discrete interact

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13

Scott, Nicholas, Tetsu Hara, Paul A. Hwang, and Edward J. Walsh. "Directionality and Crest Length Statistics of Steep Waves in Open Ocean Waters." Journal of Atmospheric and Oceanic Technology 22, no. 3 (2005): 272–81. http://dx.doi.org/10.1175/jtech1703.1.

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Abstract A new wavelet analysis methodology is applied to open ocean wave height data from the Southern Ocean Waves Experiment (1992) and from a field experiment conducted at Duck, North Carolina, in 1997 with the aim of estimating the directionality and crest lengths of steep waves. The crest directionality statistic shows that most of the steep wave crests are normal to the direction of the mean wind. This is inconsistent with the Fourier wavenumber spectrum that shows a broad bimodal directional spreading at high wavenumbers. The crest length statistics demonstrate that the wave field is do

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14

Tannuri, Eduardo A., João V. Sparano, Alexandre N. Simos, and José J. Da Cruz. "Estimating directional wave spectrum based on stationary ship motion measurements." Applied Ocean Research 25, no. 5 (2003): 243–61. http://dx.doi.org/10.1016/j.apor.2004.01.003.

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15

Ohshimo, Tetsunori, Kosuke Kondo, and Tsunehiro Sekimoto. "OBSERVATION OF DIRECTIONAL WAVE SPECTRA AND REFLECTION COEFFICIENT OF BREAKWATER IN A HARBOR." Coastal Engineering Proceedings 1, no. 21 (1988): 3. http://dx.doi.org/10.9753/icce.v21.3.

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Field investigations were performed in order to show the effect of wave diffraction by breakwaters through directional wave spectra measurements in a harbor, and to estimate the reflection coefficient by resolving the incident and reflected wave energy in front of a composite type breakwater. Combinations of an ultrasonic wave gage (USW) and an electromagnetic current meter (EMC) were used to measure the synchronized data of the water surface elevation and two horizontal velocities. The EMLM (Extended Maximum Likelihood Method) was applied for the calculation of the directional wave spectrum,

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16

Ewans, K. C., and T. van der Vlugt. "Estimating Bimodal Frequency-Direction Spectra From Surface Buoy Data Recorded During Tropical Cyclones." Journal of Offshore Mechanics and Arctic Engineering 121, no. 3 (1999): 172–80. http://dx.doi.org/10.1115/1.2829562.

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Techniques for computing wave frequency-direction spectra are evaluated using wave buoy data recorded on the North West Shelf of Australia. Frequency-direction spectra are computed by each of four techniques and compared with the wave directionality expected at the measurement location, based on the meteorological conditions prevailing at the time. Particular emphasis is placed on the wave conditions occurring during tropical cyclones. Such sea states show strong directional bimodality, consisting largely of a cyclone-generated swell component and a local wind sea. The cyclone swell can be exp

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17

Perrie, William, and Donald T. Resio. "A Two-Scale Approximation for Efficient Representation of Nonlinear Energy Transfers in a Wind Wave Spectrum. Part II: Application to Observed Wave Spectra." Journal of Physical Oceanography 39, no. 10 (2009): 2451–76. http://dx.doi.org/10.1175/2009jpo3947.1.

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Abstract In Part I of this series, a new method for estimating nonlinear transfer rates in wind waves, based on a two-scale approximation (TSA) to the full Boltzmann integral (FBI) for quadruplet wave–wave interactions, was presented, and this new method was tested for idealized spectral data. Here, the focus is on comparisons of the TSA and the discrete interaction approximation (DIA) with the FBI for observed wave spectra from field measurements. Observed wave spectra are taken from a wave gauge array in Currituck Sound and a directional waverider off the coast near the Field Research Facili

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18

Hisaki, Yukiharu. "Ocean Wave Directional Spectra Estimation from an HF Ocean Radar with a Single Antenna Array: Methodology." Journal of Atmospheric and Oceanic Technology 23, no. 2 (2006): 268–86. http://dx.doi.org/10.1175/jtech1836.1.

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Abstract A method to estimate ocean wave directional spectra using a high-frequency (HF) ocean radar was developed. The governing equations of wave spectra are integral equations of first- and second-order radar cross sections, the wave energy balance equation, and the continuity equation of surface winds. The parameterization of the source function is the same as that in WAM. Furthermore, the method uses the constraints that wave spectral values are smooth in both wave frequency and direction and that the propagation terms are small. The unknowns to be estimated are surface wind vectors at ra

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19

Petersen, Ø. W., O. Øiseth, and E. Lourens. "Full-scale identification of the wave forces exerted on a floating bridge using inverse methods and directional wave spectrum estimation." Mechanical Systems and Signal Processing 120 (April 2019): 708–26. http://dx.doi.org/10.1016/j.ymssp.2018.10.040.

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20

Takezawa, Seiji, Tsugukiyo Hirayama, Seiya Ueno, and Xuefeng Wang. "Estimation of Directional Frequency Response Functions of a Running Ship Based on Experiments in Directional Spectrum Waves." Journal of the Society of Naval Architects of Japan 1991, no. 170 (1991): 163–71. http://dx.doi.org/10.2534/jjasnaoe1968.1991.170_163.

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21

Plant, William J., and Mark A. Donelan. "Directional Surface Wave Spectra from Point Measurements of Height and Slope." Journal of Atmospheric and Oceanic Technology 37, no. 1 (2020): 67–83. http://dx.doi.org/10.1175/jtech-d-19-0128.1.

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AbstractWe describe here a method for recovering directional ocean surface wave spectra obtained from height and slope measurements made over a small area, the iterative deconvolution method (IDM). We show that IDM is a more reliable method for estimating directional wave spectra than more common spectral estimation techniques by comparing it with the widely used maximum entropy method (MEM). IDM is based on the observation that pitch–roll buoys produce directional spectra that are the true spectra convolved with an angular windowing function and are therefore much broader than the true spectr

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22

Simanesew, Abushet W., Harald E. Krogstad, Karsten Trulsen, and José Carlos Nieto Borge. "Bimodality of Directional Distributions in Ocean Wave Spectra: A Comparison of Data-Adaptive Estimation Techniques." Journal of Atmospheric and Oceanic Technology 35, no. 2 (2018): 365–84. http://dx.doi.org/10.1175/jtech-d-17-0007.1.

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AbstractThe properties of directional distributions in ocean wave spectra are studied, with an emphasis on sea states with bimodal directional distributions in the high-frequency tails of single-peaked wave systems. A peak-splitting tendency has been a challenge in the interpretation of results from some data-adaptive estimation methods. After a survey of the theory, mathematical and numerical explanations are presented regarding domains of uni- and bimodality for symmetric Burg and Shannon maximum entropy methods. The study finds that both the Burg and Shannon maximum entropy methods have a t

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23

Takezawa, Seiji, Tsugukiyo Hirayama, Seiya Ueno, and Chen Gan. "Estimation of directional frequency response functions of a floating offshore structure based on experiments in directional spectrum waves." Journal of the Society of Naval Architects of Japan 1990, no. 168 (1990): 261–66. http://dx.doi.org/10.2534/jjasnaoe1968.1990.168_261.

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24

Jensen, Robert Edward, Val Swail, and Richard Harry Bouchard. "Quantifying wave measurement differences in historical and present wave buoy systems." Ocean Dynamics 71, no. 6-7 (2021): 731–55. http://dx.doi.org/10.1007/s10236-021-01461-0.

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AbstractAn intra-measurement evaluation was undertaken, deploying a NOMAD buoy equipped with three National Data Buoy Center and two Environment and Climate Change Canada-AXYS sensor/payload packages off Monterey, California; a Datawell Directional Waverider buoy was deployed within 19 km of the NOMAD site. The six independent wave measurement systems reported hourly estimates of the frequency spectra, and when applicable, the four Fourier directional components. The integral wave parameters showed general agreement among the five sensors compared to the neighboring Datawell Directional Waveri

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25

Rossi, Giovanni Battista, Francesco Crenna, Marta Berardengo, Vincenzo Piscopo, and Antonio Scamardella. "Investigation on Spectrum Estimation Methods for Bimodal Sea State Conditions." Sensors 21, no. 9 (2021): 2995. http://dx.doi.org/10.3390/s21092995.

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The reliable monitoring of sea state parameters is a key factor for weather forecasting, as well as for ensuring the safety and navigation of ships. In the current analysis, two spectrum estimation techniques, based on the Welch and Thomson methods, were applied to a set of random wave signals generated from a theoretical wave spectrum obtained by combining wind sea and swell components with the same prevailing direction but different combinations of significant wave heights, peak periods, and peak enhancement factors. A wide benchmark study was performed to systematically apply and compare th

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26

Nassim, Aarab Mohamed, and Chakkor Otman. "Millimeter-Wave Channel Estimation using Alternating Direction Method of Multipliers." International Journal of Innovative Technology and Exploring Engineering 10, no. 4 (2021): 239–42. http://dx.doi.org/10.35940/ijitee.d8597.0210421.

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With the explosive growth in demand for mobile data traffic, the contradiction between capacity requirements and spectrum scarcity becomes more and more prominent. The bandwidth is becoming a key issue in 5G mobile networks. However, with the huge bandwidth from 30 GHz to 300 GHz, mmWave communications considered an important part of the 5G mobile network providing multi communication services, where channel state information considers a challenging task for millimeter wave MIMO systems due to the huge number of antennas. Therefore, this paper discusses the channel and signal models of the mmW

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27

Kirpanev, A. V., N. A. Kirpanev, and V. V. Shubnikov. "On study of antenna-radome system near-field measurements with a spherical scanner." Issues of radio electronics 49, no. 9 (2020): 14–21. http://dx.doi.org/10.21778/2218-5453-2020-9-14-21.

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The paper presents a research technique for studying an antenna-radome system based on nearfield measurements with a most common «roll over azimuth» spherical scanner. It is based on the relationship between the components of the plane wave spectrum and the spherical wave coefficients, in terms of which the radiation fields of the tested antenna and the antenna-radome system are represented. Expressions for the plane wave spectrum components at the pole of the spherical measurement surface are given. To assess the effect of the radome on the antenna characteristics, it is proposed to use the s

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28

Takezawa, Seiji, Tsugukiyo Hirayama, Seiya Ueno, and Chen Gan. "Estimation of directional frequency response functions of a floating offshore structure based on experiments in directional spectrum waves (3rd report)." Journal of the Society of Naval Architects of Japan 1991, no. 170 (1991): 307–17. http://dx.doi.org/10.2534/jjasnaoe1968.1991.170_307.

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29

Takezawa, Seiji, Tsugukiyo Hirayama, Seiya Ueno, and Chen Gan. "Estimation of directional frequency response functions of a floating offshore structure based on experiments in directional spectrum waves (2nd report)." Journal of the Society of Naval Architects of Japan 1991, no. 169 (1991): 177–85. http://dx.doi.org/10.2534/jjasnaoe1968.1991.177.

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30

Ticona Rollano, Fadia, Thanh Toan Tran, Yi-Hsiang Yu, Gabriel García-Medina, and Zhaoqing Yang. "Influence of Time and Frequency Domain Wave Forcing on the Power Estimation of a Wave Energy Converter Array." Journal of Marine Science and Engineering 8, no. 3 (2020): 171. http://dx.doi.org/10.3390/jmse8030171.

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Industry-specific tools for analyzing and optimizing the design of wave energy converters (WECs) and associated power systems are essential to advancing marine renewable energy. This study aims to quantify the influence of phase information on the device power output of a virtual WEC array. We run the phase-resolving wave model FUNWAVE-TVD (Total Variation Diminishing) to generate directional waves at the PacWave South site offshore from Newport, Oregon, where future WECs are expected to be installed for testing. The two broad cases presented correspond to mean wave climates during warm months

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31

Vieira, Matheus, Pedro Veras Guimarães, Nelson Violante-Carvalho, Alvise Benetazzo, Filippo Bergamasco, and Henrique Pereira. "A Low-Cost Stereo Video System for Measuring Directional Wind Waves." Journal of Marine Science and Engineering 8, no. 11 (2020): 831. http://dx.doi.org/10.3390/jmse8110831.

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Typical oceanographic instruments are expensive, complex to build, and hard to deploy and require constant and specialized maintenance. In this paper, we present a cheap and simple technique to estimate a three-dimensional surface elevation map, η(x,y,t), the directional spectrum, and the main sea state parameters using inexpensive smartphones. The proposed methodology uses Time Lagged Cross Correlation (TLCC) between the audio signals from two independent video records to perform the frame synchronization. This makes the system much easier to deploy, where the main requirement is a fixed or m

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32

Takezawa, Seiji, Tsugukiyo Hirayama, and Chen Gang. "Simple Estimation Method of the Slow Drift Motion of a Semi-submerible in Directional Spectrum Waves." Journal of the Society of Naval Architects of Japan 1993, no. 174 (1993): 289–96. http://dx.doi.org/10.2534/jjasnaoe1968.1993.174_289.

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33

Liu, Qingxiang, W. Erick Rogers, Alexander V. Babanin, et al. "Observation-Based Source Terms in the Third-Generation Wave Model WAVEWATCH III: Updates and Verification." Journal of Physical Oceanography 49, no. 2 (2019): 489–517. http://dx.doi.org/10.1175/jpo-d-18-0137.1.

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AbstractThe observation-based source terms available in the third-generation wave model WAVEWATCH III (i.e., the ST6 package for parameterizations of wind input, wave breaking, and swell dissipation terms) are recalibrated and verified against a series of academic and realistic simulations, including the fetch/duration-limited test, a Lake Michigan hindcast, and a 1-yr global hindcast. The updated ST6 not only performs well in predicting commonly used bulk wave parameters (e.g., significant wave height and wave period) but also yields a clearly improved estimation of high-frequency energy leve

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34

Sang, Tzu-Hsien, Feng-Tsun Chien, Chia-Chih Chang, Kuan-Yu Tseng, Bo-Sheng Wang, and Jiun-In Guo. "DoA Estimation for FMCW Radar by 3D-CNN." Sensors 21, no. 16 (2021): 5319. http://dx.doi.org/10.3390/s21165319.

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A method of direction-of-arrival (DoA) estimation for FMCW (Frequency Modulated Continuous Wave) radar is presented. In addition to MUSIC, which is the popular high-resolution DoA estimation algorithm, deep learning has recently emerged as a very promising alternative. It is proposed in this paper to use a 3D convolutional neural network (CNN) for DoA estimation. The 3D-CNN extracts from the radar data cube spectrum features of the region of interest (RoI) centered on the potential positions of the targets, thereby capturing the spectrum phase shift information, which corresponds to DoA, along

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35

Pettersson, Heidi, Kimmo K. Kahma, and Laura Tuomi. "Wave Directions in a Narrow Bay." Journal of Physical Oceanography 40, no. 1 (2010): 155–69. http://dx.doi.org/10.1175/2009jpo4220.1.

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Abstract In slanting fetch conditions the direction of actively growing waves is strongly controlled by the fetch geometry. The effect was found to be pronounced in the long and narrow Gulf of Finland in the Baltic Sea, where it significantly modifies the directional wave climate. Three models with different assumptions on the directional coupling between the wave components were used to analyze the physics responsible for the directional behavior of the waves in the gulf. The directionally decoupled model produced the direction at the spectral peak correctly when the slanting fetch geometry w

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36

Zhu, Jiyou, Weijun He, Jiangming Yao, et al. "Spectral Reflectance Characteristics and Chlorophyll Content Estimation Model of Quercus aquifolioides Leaves at Different Altitudes in Sejila Mountain." Applied Sciences 10, no. 10 (2020): 3636. http://dx.doi.org/10.3390/app10103636.

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Quercus aquifolioides is one of the most representative broad-leaved plants in Qinghai-Tibet Plateau with important ecological status. So far, understanding how to quickly estimate the chlorophyll content of plants in plateau areas is still an urgent problem. Field Spec 3 spectrometer was used to measure hyperspectral reflectance data of Quercus aquifolioides leaves at different altitudes, and CCI (chlorophyll relative content) of corresponding leaves was measured by a chlorophyll meter. The correlation and univariate linear fitting analysis techniques were used to establish their relationship

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37

Zhang, Zhishuai, James W. Rector, and Michael J. Nava. "Microseismic hydraulic fracture imaging in the Marcellus Shale using head waves." GEOPHYSICS 83, no. 2 (2018): KS1—KS10. http://dx.doi.org/10.1190/geo2017-0184.1.

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We have studied microseismic data acquired from a geophone array deployed in the horizontal section of a well drilled in the Marcellus Shale near Susquehanna County, Pennsylvania. Head waves were used to improve event location accuracy as a substitution for the traditional P-wave polarization method. We identified that resonances due to poor geophone-to-borehole coupling hinder arrival-time picking and contaminate the microseismic data spectrum. The traditional method had substantially greater uncertainty in our data due to the large uncertainty in P-wave polarization direction estimation. We

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38

Neelakanta, Perambur, and Dolores De Groff. "Conceiving Inferential Prototypes of MIMO Channel Models via Buckingham’s Similitude Principle for 30+ GHz through THz Spectrum." Transactions on Networks and Communications 9, no. 3 (2021): 1–35. http://dx.doi.org/10.14738/tnc.93.10214.

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Facilitating newer bands of ‘unused’ segments (windows) of RF spectrum falling in the mm-wave range (above 30+ GHz) and seeking usable stretches across unallocated THz spectrum, could viably be considered for Multiple Input Multiple Output (MIMO) communications. This could accommodate the growing needs of multigigabit 3G/4G applications in outdoor-based backhauls in picocellular networks and in indoor-specific multimedia networking. However, in contrast with cellular and Wi-Fi, wireless systems supporting sub-mm wavelength transreceive communications in the outdoor electromagnetic (EM) ambient

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39

Qiu, Longhao, Tian Lan, and Yilin Wang. "A Sparse Perspective for Direction-of-Arrival Estimation Under Strong Near-Field Interference Environment." Sensors 20, no. 1 (2019): 163. http://dx.doi.org/10.3390/s20010163.

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Direction of arrival (DOA) estimation via sensor array is a crucial component of any passive sonar signal processing technology. In certain practical applications, however, the interested far-field targets are frequently affected by near-field interference, which may result in degradation of DOA estimation. Aiming at the direction estimation problems of far-field targets under strong near-field interference, a unified sparse representation model of far-field and near-field hybrid sources is constructed according to the various correlations in steering vectors between the planar wave and spheri

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40

Ewans, K. C., L. Vanderschuren, and P. S. Tromans. "FPSO Conference—Estimating Wind-Sea and Swell for FPSO Operability." Journal of Offshore Mechanics and Arctic Engineering 128, no. 4 (2005): 314–21. http://dx.doi.org/10.1115/1.2166653.

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The motion response of an FPSO is sensitive to the relative intensities and directions of the wind-sea and swell components in a sea state, and the operability of the FPSO is a function of the long-term variation in these components. Estimations of the operability are therefore dependent both on how the sea state is described in terms of its constituent wind-sea and swell components, and on how the long-term variability of the sea state is captured. However, there is currently no consensus on how either the sea state or its long-term variability should be described. We investigate these issues

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41

Liang, Guolong, Zhibo Shi, Longhao Qiu, Sibo Sun, and Tian Lan. "Sparse Bayesian Learning Based Direction-of-Arrival Estimation under Spatially Colored Noise Using Acoustic Hydrophone Arrays." Journal of Marine Science and Engineering 9, no. 2 (2021): 127. http://dx.doi.org/10.3390/jmse9020127.

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Direction-of-arrival (DOA) estimation in a spatially isotropic white noise background has been widely researched for decades. However, in practice, such as underwater acoustic ambient noise in shallow water, the ambient noise can be spatially colored, which may severely degrade the performance of DOA estimation. To solve this problem, this paper proposes a DOA estimation method based on sparse Bayesian learning with the modified noise model using acoustic vector hydrophone arrays. Firstly, an applicable linear noise model is established by using the prolate spheroidal wave functions (PSWFs) to

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42

Paul, Prosenjit, and Md Munjure Mowla. "3D Metallic Plate Lens Antenna based Beamspace Channel Estimation Technique for 5G Mmwave Massive MIMO Systems." International Journal of Wireless & Mobile Networks 13, no. 1 (2021): 1–16. http://dx.doi.org/10.5121/ijwmn.2021.13101.

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Beamspace channel estimation mechanism for massive MIMO (multiple input multiple output) antenna system presents a major process to compensate the 5G spectrum challenges caused by the proliferation of information from mobile devices. However, this estimation is required to ensure the perfect channel state information (CSI) for lower amount of Radio Frequency (RF) chains for each beam. In addition, phase shifter (PS) components used in this estimation need high power to select the beam in the desired direction. To overcome these limitations, in this work, we propose Regular Scanning Support Det

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Woods, Bryan K., and Ronald B. Smith. "Energy Flux and Wavelet Diagnostics of Secondary Mountain Waves." Journal of the Atmospheric Sciences 67, no. 11 (2010): 3721–38. http://dx.doi.org/10.1175/2009jas3285.1.

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Abstract In recent years, aircraft data from mountain waves have been primarily analyzed using velocity and temperature power spectrum and momentum flux estimation. Herein it is argued that energy flux wavelets (i.e., pressure–velocity wavelet cross-spectra) provide a more powerful tool for locating and classifying different types of mountain waves. In the first part of the paper, pressure–velocity cross-spectra using various linear mountain-wave solutions are shown to be capable of disentangling collocated waves with different propagation directions and wavelength. A field of group velocity v

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Laxague, Nathan J. M., Brian K. Haus, David G. Ortiz-Suslow, et al. "Passive Optical Sensing of the Near-Surface Wind-Driven Current Profile." Journal of Atmospheric and Oceanic Technology 34, no. 5 (2017): 1097–111. http://dx.doi.org/10.1175/jtech-d-16-0090.1.

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AbstractEstimation of near-surface current is essential to the estimation of upper-ocean material transport. Wind forcing and wave motions are dominant in the near-surface layer [within O(0.01) m of the surface], where the highly sheared flows can differ greatly from those at depth. This study presents a new method for remotely measuring the directional wind and wave drift current profile near to the surface (between 0.01 and 0.001 m for the laboratory and between 0.1 and 0.001 m for the field). This work follows the spectral analysis of high spatial (0.002 m) and temporal resolution (60 Hz) w

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Campana, Jeffrey, Eric J. Terrill, and Tony de Paolo. "A New Inversion Method to Obtain Upper-Ocean Current-Depth Profiles Using X-Band Observations of Deep-Water Waves." Journal of Atmospheric and Oceanic Technology 34, no. 5 (2017): 957–70. http://dx.doi.org/10.1175/jtech-d-16-0120.1.

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AbstractA new method for estimating current-depth profiles from observations of wavenumber-dependent Doppler shifts of the overlying ocean wave field is presented. Consecutive scans of marine X-band backscatter provide wave field measurements in the time–space domain that transform into the directional wavenumber–frequency domain via a 3D fast Fourier transform (FFT). Subtracting the linear dispersion shell yields Doppler shift observations in the form of (kx, ky, Δω) triplets. A constrained linear regression technique is used to extract the wavenumber-dependent effective velocities, which rep

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PICHUGIN, Vladimir N., E. V. YAGIN, A. V. LUKISHIN, O. A. PAKHOMOVA, and A. Y. HAZOV. "SPECTRAL APPROACH TO THE ESTIMATION OF THE TIME SERIES OF THE POWER CHANGE IN THE SUBSTATION METERING UNITS AND ITS APPLICATION IN THE CONTROL MODES OF SUBSTATION ELECTRICITY METERING SYSTEMS." Periódico Tchê Química 16, no. 33 (2019): 549–60. http://dx.doi.org/10.52571/ptq.v16.n33.2019.564_periodico33_pgs_549_560.pdf.

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In order to create models of extended surfaces in the long and short wavelength parts of the wave spectrum, it is necessary to know the dispersion characteristics of tape-like obstacles perfectly located both in free space and on an extended surface. Methods of remote studying of extended surfaces, based on an analysis of signals that are generated by reflection or radiation of electromagnetic waves passing neoplasms allows us to view the topography, characteristics, and type of the different locations, sizes of various objects. One of the effective methods of study is to solve the problem of

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Ding, Mingjun, Xiaodong Yang, Rui Hu, Zhitao Xiao, Jun Tong, and Jiangtao Xi. "On Matrix Completion-Based Channel Estimators for Massive MIMO Systems." Symmetry 11, no. 11 (2019): 1377. http://dx.doi.org/10.3390/sym11111377.

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Large-scale symmetric arrays such as uniform linear arrays (ULA) have been widely used in wireless communications for improving spectrum efficiency and reliability. Channel state information (CSI) is critical for optimizing massive multiple-input multiple-output(MIMO)-based wireless communication systems. The acquisition of CSI for massive MIMO faces challenges such as training shortage and high computational complexity. For millimeter wave MIMO systems, the low-rankness of the channel can be utilized to address the challenge of training shortage. In this paper, we compared several channel est

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Mentaschi, Lorenzo, Michalis Vousdoukas, Tomas Fernandez Montblanc, et al. "Assessment of global wave models on regular and unstructured grids using the Unresolved Obstacles Source Term." Ocean Dynamics 70, no. 11 (2020): 1475–83. http://dx.doi.org/10.1007/s10236-020-01410-3.

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Abstract The Unresolved Obstacles Source Term (UOST) is a general methodology for parameterizing the dissipative effects of subscale islands, cliffs, and other unresolved features in ocean wave models. Since it separates the dissipation from the energy advection scheme, it can be applied to any numerical scheme or any type of mesh. UOST is now part of the official release of WAVEWATCH III, and the freely available package alphaBetaLab automates the estimation of the parameters needed for the obstructed cells. In this contribution, an assessment of global regular and unstructured (triangular) w

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Webb, David J. "David Edgar Cartwright. 21 October 1926 — 2 December 2015." Biographical Memoirs of Fellows of the Royal Society 63 (January 2017): 99–115. http://dx.doi.org/10.1098/rsbm.2017.0001.

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David Cartwright was one of the world's leading authorities on the tides. However, when reflecting on his life, Cartwright made the point that his early scientific career was not a success. Indeed in 1953, at the age of 27, he had virtually despaired of any creative scientific future. At the time he was being pressurized to stop his work on the statistics of ship motions but his prospects rapidly changed when he was invited to apply for a post at the new National Institute of Oceanography (NIO) being set up by George Deacon. At NIO he soon made important contributions to the study of ocean wav

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Crosby, Sean C., William C. O’Reilly, and Robert T. Guza. "Modeling Long-Period Swell in Southern California: Practical Boundary Conditions from Buoy Observations and Global Wave Model Predictions." Journal of Atmospheric and Oceanic Technology 33, no. 8 (2016): 1673–90. http://dx.doi.org/10.1175/jtech-d-16-0038.1.

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AbstractAccurate, unbiased, high-resolution (in space and time) nearshore wave predictions are needed to drive models of beach erosion; coastal flooding; and alongshore transport of sediment, biota, and pollutants. On sheltered shorelines, wave predictions are sensitive to the directions of onshore propagating waves, and nearshore model prediction error is often dominated by directional uncertainty offshore. Here, regional wave model skill in highly sheltered Southern California is compared for different offshore boundary conditions created from offshore buoy observations and global wave model

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