Pub Date : 2024-03-18DOI: 10.1109/JOE.2024.3353271
Wojciech Maleika
This article describes a local polynomial interpolation (LPI) optimization used to create digital terrain models (DTM) of the seabed based on data collected via a multibeam echosounder (MBES) during a sea survey. In the studies presented in this article, the optimal parameters of this interpolation are sought in terms of the accuracy of the created models and the calculation time. The parameters to be optimized are: the size of the area from which we select the points for interpolation (radius size), the number of points involved in the local interpolation (no), and the polynomial degree used in the interpolation (poly degree). Based on the obtained results, it was shown that the optimal values of these parameters can be selected for this type of input data, and their value depends mainly on grid resolution and the density of measurement points collected during the sea survey. Based on research using various test surfaces, it has been shown that the use of properly selected interpolation parameters enables the creation of models with slightly higher accuracy. During the research, attention was also paid to the speed of calculations, which is an important aspect of the process of creating bathymetric models. It was assumed that the new method should not significantly increase the calculation time. Finally, the author proposed using a new point selection technique (named the growing radius) during LPI, which made it possible to further increase the accuracy of the created models and the speed of calculations. The results obtained are compared with other commonly used interpolation methods using the same test data, showing the good and the bad features of the optimized LPI method. The final results of the research and the conclusions presented in this article indicate that the use of the optimized LPI together with the new technique of selecting points (the growing radius) can be a better alternative to other interpolation methods used in the process of creating bathymetric models based on data from MBES.
{"title":"Local Polynomial Interpolation Method Optimization in the Process of Digital Terrain Model Creation Based on Data Collected From a Multibeam Echosounder","authors":"Wojciech Maleika","doi":"10.1109/JOE.2024.3353271","DOIUrl":"10.1109/JOE.2024.3353271","url":null,"abstract":"This article describes a local polynomial interpolation (LPI) optimization used to create digital terrain models (DTM) of the seabed based on data collected via a multibeam echosounder (MBES) during a sea survey. In the studies presented in this article, the optimal parameters of this interpolation are sought in terms of the accuracy of the created models and the calculation time. The parameters to be optimized are: the size of the area from which we select the points for interpolation (radius size), the number of points involved in the local interpolation (no), and the polynomial degree used in the interpolation (poly degree). Based on the obtained results, it was shown that the optimal values of these parameters can be selected for this type of input data, and their value depends mainly on grid resolution and the density of measurement points collected during the sea survey. Based on research using various test surfaces, it has been shown that the use of properly selected interpolation parameters enables the creation of models with slightly higher accuracy. During the research, attention was also paid to the speed of calculations, which is an important aspect of the process of creating bathymetric models. It was assumed that the new method should not significantly increase the calculation time. Finally, the author proposed using a new point selection technique (named the growing radius) during LPI, which made it possible to further increase the accuracy of the created models and the speed of calculations. The results obtained are compared with other commonly used interpolation methods using the same test data, showing the good and the bad features of the optimized LPI method. The final results of the research and the conclusions presented in this article indicate that the use of the optimized LPI together with the new technique of selecting points (the growing radius) can be a better alternative to other interpolation methods used in the process of creating bathymetric models based on data from MBES.","PeriodicalId":13191,"journal":{"name":"IEEE Journal of Oceanic Engineering","volume":"49 3","pages":"920-932"},"PeriodicalIF":3.8,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140170342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-18DOI: 10.1109/JOE.2024.3357937
Isaac Skog;Magnus Lundberg Nordenvaad;Gustaf Hendeby
A signal-of-opportunity-based method to automatically calibrate the orientations and shapes of a set of hydrophone arrays using the sound emitted from nearby ships is presented. The calibration problem is formulated as a simultaneous localization and mapping problem, where the locations, orientations, and shapes of the arrays are viewed as the unknown map states, and the position, velocity, etc., of the source as the unknown dynamic states. A sequential likelihood ratio test, together with a maximum a posteriori source location estimator, is used to automatically detect suitable sources and initialize the calibration procedure. The performance of the proposed method is evaluated using data from two 56-element hydrophone arrays. Results from two sea trials indicate that: 1) signal sources suitable for the calibration can be automatically detected; 2) the shapes and orientations of the arrays can be consistently estimated from the different data sets with shape variations of a few decimeters and orientation variations of less than 2 $^{circ }$ ; and 3) the uncertainty bounds calculated by the calibration method are in agreement with the true calibration uncertainties. Furthermore, the bearing time record from a sea trial with an autonomous mobile underwater signal source also shows the efficacy of the proposed calibration method. In the studied scenario, the root-mean-square bearing tracking error was reduced from 4 $^{circ }$ to 1 $^{circ }$ when using the calibrated array shapes compared to assuming the arrays' to be straight lines. Also, the beamforming gain increased by approximately 1 dB.
{"title":"Signals-of-Opportunity-Based Hydrophone Array Shape and Orientation Estimation","authors":"Isaac Skog;Magnus Lundberg Nordenvaad;Gustaf Hendeby","doi":"10.1109/JOE.2024.3357937","DOIUrl":"10.1109/JOE.2024.3357937","url":null,"abstract":"A signal-of-opportunity-based method to automatically calibrate the orientations and shapes of a set of hydrophone arrays using the sound emitted from nearby ships is presented. The calibration problem is formulated as a simultaneous localization and mapping problem, where the locations, orientations, and shapes of the arrays are viewed as the unknown map states, and the position, velocity, etc., of the source as the unknown dynamic states. A sequential likelihood ratio test, together with a maximum a posteriori source location estimator, is used to automatically detect suitable sources and initialize the calibration procedure. The performance of the proposed method is evaluated using data from two 56-element hydrophone arrays. Results from two sea trials indicate that: 1) signal sources suitable for the calibration can be automatically detected; 2) the shapes and orientations of the arrays can be consistently estimated from the different data sets with shape variations of a few decimeters and orientation variations of less than 2\u0000<inline-formula><tex-math>$^{circ }$</tex-math></inline-formula>\u0000; and 3) the uncertainty bounds calculated by the calibration method are in agreement with the true calibration uncertainties. Furthermore, the bearing time record from a sea trial with an autonomous mobile underwater signal source also shows the efficacy of the proposed calibration method. In the studied scenario, the root-mean-square bearing tracking error was reduced from 4\u0000<inline-formula><tex-math>$^{circ }$</tex-math></inline-formula>\u0000 to 1\u0000<inline-formula><tex-math>$^{circ }$</tex-math></inline-formula>\u0000 when using the calibrated array shapes compared to assuming the arrays' to be straight lines. Also, the beamforming gain increased by approximately 1 dB.","PeriodicalId":13191,"journal":{"name":"IEEE Journal of Oceanic Engineering","volume":"49 3","pages":"679-691"},"PeriodicalIF":3.8,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140170543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-16DOI: 10.1109/JOE.2024.3378409
Xingbin Tu;Yan Wei;Fengzhong Qu;Aijun Song
The adaptive recursive least squares (RLS) algorithm plays a crucial role in underwater acoustic (UWA) communications because of its robustness and fast convergence. However, the high computational complexity of the RLS algorithm has limited its application in UWA channels with long delay spreads. Two strategies can be developed to reduce the complexity of the RLS algorithm. The first one is to directly reduce the complexity considering the algorithm itself. Here, we exploit the dichotomous coordinate descent (DCD) algorithm to achieve low complexity. Since the received signals from multiple hydrophones are compensated with fluctuating phase increments at each instant, the shift structure of the input sequence, which enables a significant reduction in the complexity of updating the correlation matrix of the input vector in the DCD algorithm, is no longer applicable in UWA channels. To make the DCD algorithm compatible with the nonshifted structure of input sequence, a partial updating approach is employed for the correlation matrix of the input sequence over time in the RLS algorithm. This approach skips cases with small phase variations and only updates the cross-correlation submatrix. In this way, constant and full-scale phase compensation is avoided. The other strategy is to shorten the channel length. Here, we exploit the iterative frequency-domain equalization (FDE) to suppress the intersymbol interference from multipaths. The received signal is first partitioned into overlapping subblocks for iterative FDE. A weighting processing with a subblock forgetting factor is designed to make the mean squared error continuous across subblocks and iterations in the RLS algorithm. Both the strategies were adopted in the decision-feedback equalization (DFE) and examined by simulations and experiments. Results demonstrate that the proposed algorithms approximate or outperform the traditional RLS-based DFE with much lower computational overheads in channels with small delay spreads and fluctuation rates. For the improved DCD-RLS-based DFE, a threshold provides a tradeoff between the performance and complexity. For the FDE-RLS-based DFE, the mean squared error and computational complexity induced by long equalizer taps can be kept at low levels due to channel shortening. The latter algorithm remains effective even as channel delays and fluctuation rates increase.
{"title":"Low Computational Complexity RLS-Based Decision-Feedback Equalization in Underwater Acoustic Communications","authors":"Xingbin Tu;Yan Wei;Fengzhong Qu;Aijun Song","doi":"10.1109/JOE.2024.3378409","DOIUrl":"10.1109/JOE.2024.3378409","url":null,"abstract":"The adaptive recursive least squares (RLS) algorithm plays a crucial role in underwater acoustic (UWA) communications because of its robustness and fast convergence. However, the high computational complexity of the RLS algorithm has limited its application in UWA channels with long delay spreads. Two strategies can be developed to reduce the complexity of the RLS algorithm. The first one is to directly reduce the complexity considering the algorithm itself. Here, we exploit the dichotomous coordinate descent (DCD) algorithm to achieve low complexity. Since the received signals from multiple hydrophones are compensated with fluctuating phase increments at each instant, the shift structure of the input sequence, which enables a significant reduction in the complexity of updating the correlation matrix of the input vector in the DCD algorithm, is no longer applicable in UWA channels. To make the DCD algorithm compatible with the nonshifted structure of input sequence, a partial updating approach is employed for the correlation matrix of the input sequence over time in the RLS algorithm. This approach skips cases with small phase variations and only updates the cross-correlation submatrix. In this way, constant and full-scale phase compensation is avoided. The other strategy is to shorten the channel length. Here, we exploit the iterative frequency-domain equalization (FDE) to suppress the intersymbol interference from multipaths. The received signal is first partitioned into overlapping subblocks for iterative FDE. A weighting processing with a subblock forgetting factor is designed to make the mean squared error continuous across subblocks and iterations in the RLS algorithm. Both the strategies were adopted in the decision-feedback equalization (DFE) and examined by simulations and experiments. Results demonstrate that the proposed algorithms approximate or outperform the traditional RLS-based DFE with much lower computational overheads in channels with small delay spreads and fluctuation rates. For the improved DCD-RLS-based DFE, a threshold provides a tradeoff between the performance and complexity. For the FDE-RLS-based DFE, the mean squared error and computational complexity induced by long equalizer taps can be kept at low levels due to channel shortening. The latter algorithm remains effective even as channel delays and fluctuation rates increase.","PeriodicalId":13191,"journal":{"name":"IEEE Journal of Oceanic Engineering","volume":"49 3","pages":"1067-1088"},"PeriodicalIF":3.8,"publicationDate":"2024-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141062127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-16DOI: 10.1109/JOE.2024.3382005
Shui-Rong Chai;Yu-Feng Zou;Ke Li;Juan Li;Yi-Wen Wei;Li-Xin Guo;Long Li
In this article, the small slope approximation in conjunction with the equivalent medium method is applied to analyze the acoustic scattering from a rough bubbly ocean surface, in which seawater with bubbles is regarded as a special medium, and the effect of subsurface bubbles is considered to have three main aspects: First, the attenuation effect, which is manifested as sound energy absorption, effective wave number correction, and sound speed reduction. Second, the modulation of incident and scattering angles of sound waves. Third, the volume scattering by bubbles. Also, it should be pointed out that different from previous papers, the rough sea surface is established, the acoustic scattering from each rough sea surface is simulated and an ensemble average is performed. By comparing with critical sea test results, it is found that the algorithm in this article can effectively predict the acoustic scattering from the sea surface with bubbles. The bistatic and monostatic acoustic scattering strength of the rough bubbly ocean surface under different conditions are calculated and discussed in detail. The results show that the peak of scattering strength appears in the direction of the specular scattering angle, and the farther away from the specular direction, the smaller the scattering strength. As the wind speed increases, the scattering strength first decreases and then stabilizes in the specular scattering direction, first increases and then stabilizes in the forward scattering direction, and continuously increases in the back-scattering direction.
{"title":"Acoustic Scattering From Rough Bubbly Ocean Surface Based on SSA and EMM","authors":"Shui-Rong Chai;Yu-Feng Zou;Ke Li;Juan Li;Yi-Wen Wei;Li-Xin Guo;Long Li","doi":"10.1109/JOE.2024.3382005","DOIUrl":"10.1109/JOE.2024.3382005","url":null,"abstract":"In this article, the small slope approximation in conjunction with the equivalent medium method is applied to analyze the acoustic scattering from a rough bubbly ocean surface, in which seawater with bubbles is regarded as a special medium, and the effect of subsurface bubbles is considered to have three main aspects: First, the attenuation effect, which is manifested as sound energy absorption, effective wave number correction, and sound speed reduction. Second, the modulation of incident and scattering angles of sound waves. Third, the volume scattering by bubbles. Also, it should be pointed out that different from previous papers, the rough sea surface is established, the acoustic scattering from each rough sea surface is simulated and an ensemble average is performed. By comparing with critical sea test results, it is found that the algorithm in this article can effectively predict the acoustic scattering from the sea surface with bubbles. The bistatic and monostatic acoustic scattering strength of the rough bubbly ocean surface under different conditions are calculated and discussed in detail. The results show that the peak of scattering strength appears in the direction of the specular scattering angle, and the farther away from the specular direction, the smaller the scattering strength. As the wind speed increases, the scattering strength first decreases and then stabilizes in the specular scattering direction, first increases and then stabilizes in the forward scattering direction, and continuously increases in the back-scattering direction.","PeriodicalId":13191,"journal":{"name":"IEEE Journal of Oceanic Engineering","volume":"49 3","pages":"1039-1050"},"PeriodicalIF":3.8,"publicationDate":"2024-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141062094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-14DOI: 10.1109/JOE.2024.3361968
Brian T. Hefner;Dajun Tang;William S. Hodgkiss
To support the modeling of reverberation data collected during the Target and Reverberation Experiment in 2013 (TREX13), transmission loss was measured in the 1.5–4.0 kHz band using a towed source and two moored vertical line arrays. The experiment site was located off the coast of Panama City Beach, FL, and the transmission loss measurements took place along a 7-km-long isobath, which ran parallel to the shore with a water depth of approximately 19 m. The seafloor at the TREX13 site consists of sand ridges, which run perpendicular to the track of the experiment, with narrow bands of softer sediments on the western sides of the ridges and in the ridge swales. Using data from a multibeam echosounder survey and direct measurements of the seafloor properties, a geoacoustic description of the seafloor is developed and used to model the transmission loss at the site. Although the soft-sediment bands only occur in 27% of the seafloor, they are found to have a significant impact on the transmission loss, increasing it by roughly 5 dB at 4 km over what would be expected from an entirely sand sediment. This is consistent with the previous work by Holland who showed that lossiest sediments play the largest role in propagation over range-dependent seabeds. Simulations also show that the exact locations of the soft sediments are less important for controlling propagation in the TREX13 environment than the proportions of the sediments. This suggests that a range-independent, effective media description of the sediment could be used to model propagation at the site. The limits of the use of an effective medium in describing both propagation and reverberation measurements made during TREX13 are considered.
{"title":"The Impact of the Spatial Variability of the Seafloor on Midfrequency Sound Propagation During the Target and Reverberation Experiment 2013","authors":"Brian T. Hefner;Dajun Tang;William S. Hodgkiss","doi":"10.1109/JOE.2024.3361968","DOIUrl":"10.1109/JOE.2024.3361968","url":null,"abstract":"To support the modeling of reverberation data collected during the Target and Reverberation Experiment in 2013 (TREX13), transmission loss was measured in the 1.5–4.0 kHz band using a towed source and two moored vertical line arrays. The experiment site was located off the coast of Panama City Beach, FL, and the transmission loss measurements took place along a 7-km-long isobath, which ran parallel to the shore with a water depth of approximately 19 m. The seafloor at the TREX13 site consists of sand ridges, which run perpendicular to the track of the experiment, with narrow bands of softer sediments on the western sides of the ridges and in the ridge swales. Using data from a multibeam echosounder survey and direct measurements of the seafloor properties, a geoacoustic description of the seafloor is developed and used to model the transmission loss at the site. Although the soft-sediment bands only occur in 27% of the seafloor, they are found to have a significant impact on the transmission loss, increasing it by roughly 5 dB at 4 km over what would be expected from an entirely sand sediment. This is consistent with the previous work by Holland who showed that lossiest sediments play the largest role in propagation over range-dependent seabeds. Simulations also show that the exact locations of the soft sediments are less important for controlling propagation in the TREX13 environment than the proportions of the sediments. This suggests that a range-independent, effective media description of the sediment could be used to model propagation at the site. The limits of the use of an effective medium in describing both propagation and reverberation measurements made during TREX13 are considered.","PeriodicalId":13191,"journal":{"name":"IEEE Journal of Oceanic Engineering","volume":"49 3","pages":"1025-1038"},"PeriodicalIF":3.8,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140152853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-14DOI: 10.1109/JOE.2024.3378408
Austin B. Schmidt;Pujan Pokhrel;Mahdi Abdelguerfi;Elias Ioup;David Dobson
Methodologies inspired by physics-informed neural networks (PINNs) were used to forecast observations recorded by stationary ocean buoys. We combined buoy observations with numerical models to train surrogate deep learning networks that performed better than with either data alone. Numerical model outputs were collected from two sources for training and regularization: the hybrid circulation ocean model and the fifth European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis experiment. A hyperparameter determines the ratio of observational and modeled data to be used in the training procedure, so we conducted a grid search to find the most performant ratio. Overall, the technique improved the general forecast performance compared with nonregularized models. Under specific circumstances, the regularization mechanism enabled the PINN models to be more accurate than the numerical models. This demonstrates the utility of combining various climate models and sensor observations to improve surrogate modeling.
{"title":"Forecasting Buoy Observations Using Physics-Informed Neural Networks","authors":"Austin B. Schmidt;Pujan Pokhrel;Mahdi Abdelguerfi;Elias Ioup;David Dobson","doi":"10.1109/JOE.2024.3378408","DOIUrl":"10.1109/JOE.2024.3378408","url":null,"abstract":"Methodologies inspired by physics-informed neural networks (PINNs) were used to forecast observations recorded by stationary ocean buoys. We combined buoy observations with numerical models to train surrogate deep learning networks that performed better than with either data alone. Numerical model outputs were collected from two sources for training and regularization: the hybrid circulation ocean model and the fifth European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis experiment. A hyperparameter determines the ratio of observational and modeled data to be used in the training procedure, so we conducted a grid search to find the most performant ratio. Overall, the technique improved the general forecast performance compared with nonregularized models. Under specific circumstances, the regularization mechanism enabled the PINN models to be more accurate than the numerical models. This demonstrates the utility of combining various climate models and sensor observations to improve surrogate modeling.","PeriodicalId":13191,"journal":{"name":"IEEE Journal of Oceanic Engineering","volume":"49 3","pages":"821-840"},"PeriodicalIF":3.8,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141062169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-14DOI: 10.1109/JOE.2024.3372701
Yosaku Maeda;Tatsuya Aso;Hiroshi Uchida
Even for ultra deep sea applications, pressure housings using ceramics can obtain positive buoyancy because ceramics typically have an outstanding compressive strength-to-weight ratio and elastic modulus. Nevertheless, ceramic housings have not been used widely to date because their characteristics as brittle materials complicate design efforts. This article presents a design method for a ceramic tube pressure housing applicable to ultra deep sea usage, particularly addressing the material properties of the metal end caps which contact the bearing surface of the ceramic tube. The housing consists of aluminum alloy end caps and a ceramic tube with wall thickness determined using a critical buckling equation for infinite cylinder length. The cap design uses only the conventional method for metal housing without a special design for reducing tensile stress on the ceramic cylinder. An investigation based on plastic contact mechanics indicates that aluminum alloy caps that have lower yield strength and an elastic and tangent modulus than those of other metals reduce tensile stress at the ceramic tube end via reduction of the contact pressure. Furthermore, nonlinear finite element analysis results indicate only slight tensile stress on the end surfaces of the ceramic tube and provide markedly low tensile failure probability. Comparison to simulated results with the titanium alloy cap model highlights the aluminum alloy cap's effectiveness at reducing tensile stress on the ceramic tube end. The reliability of this simple and easily introduced design method for ceramic tube housings is demonstrated through pressure testing and observations.
{"title":"Simple Design Method for Ceramic Tube Pressure Housings","authors":"Yosaku Maeda;Tatsuya Aso;Hiroshi Uchida","doi":"10.1109/JOE.2024.3372701","DOIUrl":"10.1109/JOE.2024.3372701","url":null,"abstract":"Even for ultra deep sea applications, pressure housings using ceramics can obtain positive buoyancy because ceramics typically have an outstanding compressive strength-to-weight ratio and elastic modulus. Nevertheless, ceramic housings have not been used widely to date because their characteristics as brittle materials complicate design efforts. This article presents a design method for a ceramic tube pressure housing applicable to ultra deep sea usage, particularly addressing the material properties of the metal end caps which contact the bearing surface of the ceramic tube. The housing consists of aluminum alloy end caps and a ceramic tube with wall thickness determined using a critical buckling equation for infinite cylinder length. The cap design uses only the conventional method for metal housing without a special design for reducing tensile stress on the ceramic cylinder. An investigation based on plastic contact mechanics indicates that aluminum alloy caps that have lower yield strength and an elastic and tangent modulus than those of other metals reduce tensile stress at the ceramic tube end via reduction of the contact pressure. Furthermore, nonlinear finite element analysis results indicate only slight tensile stress on the end surfaces of the ceramic tube and provide markedly low tensile failure probability. Comparison to simulated results with the titanium alloy cap model highlights the aluminum alloy cap's effectiveness at reducing tensile stress on the ceramic tube end. The reliability of this simple and easily introduced design method for ceramic tube housings is demonstrated through pressure testing and observations.","PeriodicalId":13191,"journal":{"name":"IEEE Journal of Oceanic Engineering","volume":"49 3","pages":"749-762"},"PeriodicalIF":3.8,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141062170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In polar regions, coastal polynyas are key drivers for climate since they represent the primary source of ice mass production and oceanic circulation. In this study, multipolarization C-band synthetic aperture radar (SAR) measurements acquired by the Radarsat-2 satellite mission are exploited to observe the Terra Nova Bay (TNB) coastal polynya in the Ross Sea, Antarctica. Incoherent and coherent features, extracted from dual-polarimetric SAR measurements, are used to characterize the TNB coastal polynya under different environmental conditions. The analysis is also supported, when available, by independent optical remote sensing information collected by the thermal infrared channels of the moderate resolution imaging spectroradiometer and by ancillary on-site information about wind and air temperature collected by automatic weather stations. Experimental results show that the SAR plays a key role in providing information about the TNB polynya thanks to its fine spatial resolution and its almost continuous imaging capabilities. In addition, dual-polarimetric SAR offers unprecedented opportunities with respect to single-polarization SAR in performing accurate and unsupervised classification of the area within the polynya. Hence, a more accurate estimation of the polynya extent and the fractional area coverage of sea water within the polynyas obtained.
在极地地区，沿岸多旋回带是气候的主要驱动力，因为它们是冰体生成和海洋环流的主要来源。本研究利用雷达卫星 2 号卫星任务获取的多极化 C 波段合成孔径雷达（SAR）测量数据，观测了南极罗斯海 Terra Nova 海湾（TNB）沿岸多能区。从双偏振合成孔径雷达测量中提取的非相干和相干特征，用于描述不同环境条件下 TNB 沿岸多谷的特征。中分辨率成像分光仪热红外通道收集到的独立光学遥感信息以及自动气象站收集到的有关风和气温的现场辅助信息也为分析提供了支持。实验结果表明，合成孔径雷达凭借其精细的空间分辨率和几乎连续的成像能力，在提供有关 TNB 极地的信息方面发挥了关键作用。此外，与单极化合成孔径雷达相比，双极化合成孔径雷达在对极地内的区域进行准确和无监督分类方面提供了前所未有的机会。因此，可以更准确地估算多能区范围和多能区内海水的部分覆盖面积。
{"title":"Characterization of the Terra Nova Bay Polynya Using Dual-Polarimetric C-Band SAR Measurements","authors":"Giovanna Inserra;Andrea Buono;Ferdinando Nunziata;Maurizio Migliaccio;Flavio Parmiggiani;Giuseppe Aulicino","doi":"10.1109/JOE.2024.3356569","DOIUrl":"10.1109/JOE.2024.3356569","url":null,"abstract":"In polar regions, coastal polynyas are key drivers for climate since they represent the primary source of ice mass production and oceanic circulation. In this study, multipolarization C-band synthetic aperture radar (SAR) measurements acquired by the Radarsat-2 satellite mission are exploited to observe the Terra Nova Bay (TNB) coastal polynya in the Ross Sea, Antarctica. Incoherent and coherent features, extracted from dual-polarimetric SAR measurements, are used to characterize the TNB coastal polynya under different environmental conditions. The analysis is also supported, when available, by independent optical remote sensing information collected by the thermal infrared channels of the moderate resolution imaging spectroradiometer and by ancillary on-site information about wind and air temperature collected by automatic weather stations. Experimental results show that the SAR plays a key role in providing information about the TNB polynya thanks to its fine spatial resolution and its almost continuous imaging capabilities. In addition, dual-polarimetric SAR offers unprecedented opportunities with respect to single-polarization SAR in performing accurate and unsupervised classification of the area within the polynya. Hence, a more accurate estimation of the polynya extent and the fractional area coverage of sea water within the polynyas obtained.","PeriodicalId":13191,"journal":{"name":"IEEE Journal of Oceanic Engineering","volume":"49 3","pages":"856-869"},"PeriodicalIF":3.8,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10472049","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140126405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-13DOI: 10.1109/JOE.2024.3350746
Jianqun Zhou;Yang Li;Hongmao Qin;Pengwen Dai;Zilong Zhao;Manjiang Hu
Acquiring large amounts of high-quality real sonar data for object detection of autonomous underwater vehicles (AUVs) is challenging. Synthetic data can be an alternative, but it is hard to generate diverse data using traditional generative models when real data are limited. This study proposes a novel style transfer method, i.e., the multigranular feature alignment cycle-consistent generative adversarial network (CycleGAN), to generate sonar images leveraging remote sensing images, which can alleviate the dependence on real sonar data. Specifically, we add a spatial attention-based feature aggregation module to preserve unique features by attending to instance parts of an image. A pair of cross-domain discriminators are designed to guide generators to produce images that capture sonar styles. We also introduce a novel cycle consistency loss based on the discrete cosine transform of images, which better utilizes features that are evident in the frequency domain. Extensive experimental results show that the generated sonar images have better quality than CycleGAN, with improvements of 15.2% in IS, 56.9% in FID, 42.6% in KID, and 7.6% in learned perceptual image patch similarity, respectively. Moreover, after expanding the real sonar dataset with generated data, the average accuracy of the object detector, e.g., YOLOv6, has increased by more than 48.7%, indicating the effectiveness of the generated sonar data by our method.
{"title":"Sonar Image Generation by MFA-CycleGAN for Boosting Underwater Object Detection of AUVs","authors":"Jianqun Zhou;Yang Li;Hongmao Qin;Pengwen Dai;Zilong Zhao;Manjiang Hu","doi":"10.1109/JOE.2024.3350746","DOIUrl":"10.1109/JOE.2024.3350746","url":null,"abstract":"Acquiring large amounts of high-quality real sonar data for object detection of autonomous underwater vehicles (AUVs) is challenging. Synthetic data can be an alternative, but it is hard to generate diverse data using traditional generative models when real data are limited. This study proposes a novel style transfer method, i.e., the multigranular feature alignment cycle-consistent generative adversarial network (CycleGAN), to generate sonar images leveraging remote sensing images, which can alleviate the dependence on real sonar data. Specifically, we add a spatial attention-based feature aggregation module to preserve unique features by attending to instance parts of an image. A pair of cross-domain discriminators are designed to guide generators to produce images that capture sonar styles. We also introduce a novel cycle consistency loss based on the discrete cosine transform of images, which better utilizes features that are evident in the frequency domain. Extensive experimental results show that the generated sonar images have better quality than CycleGAN, with improvements of 15.2% in IS, 56.9% in FID, 42.6% in KID, and 7.6% in learned perceptual image patch similarity, respectively. Moreover, after expanding the real sonar dataset with generated data, the average accuracy of the object detector, e.g., YOLOv6, has increased by more than 48.7%, indicating the effectiveness of the generated sonar data by our method.","PeriodicalId":13191,"journal":{"name":"IEEE Journal of Oceanic Engineering","volume":"49 3","pages":"905-919"},"PeriodicalIF":3.8,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140126679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-11DOI: 10.1109/JOE.2024.3353413
Zhongguang Li;Shuang Liang;Mingming Guo;Hua Zhang;Heng Wang;Zebin Li;Haoyang Li
This article investigates the underwater navigation control of a water–air amphibious multirotor vehicle. We use active disturbance rejection control (ADRC) to construct a tandem-level ADRC motion controller for the water–air multirotor vehicle and introduce particle swarm optimization (PSO) to quickly tune controller parameters. First, the amphibious multirotor vehicle's governing kinematic and dynamic equations are derived. Then, the hydrodynamics of the underwater navigation process is analyzed and estimated. Accordingly, ADRC-based position and attitude controllers are designed and compared with a traditional proportional–integral–derivative (PID) controller and a sliding mode controller (SMC). In addition, PSO is introduced to adjust the gain parameters of the PID, SMC controller, and the parameters of the nonlinear state error feedback law and extended state observer of the ADRC controller. Finally, to verify the stability and robustness of the ADRC controller, simulations are performed under strong external disturbances with a water–air multirotor vehicle. The results demonstrate that controller performance can be improved by introducing PSO to tune the controller parameters and that it is more beneficial for the self-adjacent controller with many control parameters and strong interparameter nonlinearity. ADRC responds faster, rejects external disturbances better, and is more robust than SMC and PID, which permits it to meet the performance requirements of the controller in complex underwater environments.
{"title":"ADRC-Based Underwater Navigation Control and Parameter Tuning of an Amphibious Multirotor Vehicle","authors":"Zhongguang Li;Shuang Liang;Mingming Guo;Hua Zhang;Heng Wang;Zebin Li;Haoyang Li","doi":"10.1109/JOE.2024.3353413","DOIUrl":"10.1109/JOE.2024.3353413","url":null,"abstract":"This article investigates the underwater navigation control of a water–air amphibious multirotor vehicle. We use active disturbance rejection control (ADRC) to construct a tandem-level ADRC motion controller for the water–air multirotor vehicle and introduce particle swarm optimization (PSO) to quickly tune controller parameters. First, the amphibious multirotor vehicle's governing kinematic and dynamic equations are derived. Then, the hydrodynamics of the underwater navigation process is analyzed and estimated. Accordingly, ADRC-based position and attitude controllers are designed and compared with a traditional proportional–integral–derivative (PID) controller and a sliding mode controller (SMC). In addition, PSO is introduced to adjust the gain parameters of the PID, SMC controller, and the parameters of the nonlinear state error feedback law and extended state observer of the ADRC controller. Finally, to verify the stability and robustness of the ADRC controller, simulations are performed under strong external disturbances with a water–air multirotor vehicle. The results demonstrate that controller performance can be improved by introducing PSO to tune the controller parameters and that it is more beneficial for the self-adjacent controller with many control parameters and strong interparameter nonlinearity. ADRC responds faster, rejects external disturbances better, and is more robust than SMC and PID, which permits it to meet the performance requirements of the controller in complex underwater environments.","PeriodicalId":13191,"journal":{"name":"IEEE Journal of Oceanic Engineering","volume":"49 3","pages":"775-792"},"PeriodicalIF":3.8,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140107760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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