OCEANS 2009最新文献_第3页

Rapid inversion in shallow water with a single receiver using modal time-frequency pattern extraction 利用模态时频方向图提取的单接收机浅水快速反演

OCEANS 2009 Pub Date : 2009-10-26 DOI: 10.23919/OCEANS.2009.5422409

J. Bonnel, B. Nicolas, D. Fattaccioli

引用次数: 2

Adaptive control of small outboard-powered boats for survey applications 测量用小型舷外动力船的自适应控制

OCEANS 2009 Pub Date : 2009-10-26 DOI: 10.23919/OCEANS.2009.5422380

A. Fisher, James H. VanZwieten, T. VanZwieten

{"title":"Adaptive control of small outboard-powered boats for survey applications","authors":"A. Fisher, James H. VanZwieten, T. VanZwieten","doi":"10.23919/OCEANS.2009.5422380","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422380","url":null,"abstract":"Four autopilot controllers have been developed in this work that can both hold a desired heading and follow a straight line. These PID, adaptive PID, neuro-adaptive, and adaptive augmenting control algorithms have all been implemented into a numerical simulation of a 33-foot center console vessel with wind, waves, and current disturbances acting in the perpendicular (across-track) direction of the boat's desired trajectory. Each controller is tested for its ability to follow a desired heading in the presence of these disturbances and then to follow a straight line at two different throttle settings for the same disturbances. These controllers were tuned for an input thrust of 2000 N and all four controllers showed good performance with none of the controllers significantly outperforming the others when holding a constant heading and following a straight line at this engine thrust. Each controller was then tested for a reduced engine thrust of 1200 N per engine where each of the three adaptive controllers reduced heading error and across-track error by approximately 50% after a 300 second tuning period when compared to the fixed gain PID, showing that significant robustness to changes in throttle setting was gained by using an adaptive algorithm.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125261026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Frequency warping for waveguide characterization with a single hydrophone 单水听器波导特性的频率翘曲

OCEANS 2009 Pub Date : 2009-10-26 DOI: 10.23919/oceans.2009.5422406

J. Bonnel, B. Nicolas, D. Fattaccioli

{"title":"Frequency warping for waveguide characterization with a single hydrophone","authors":"J. Bonnel, B. Nicolas, D. Fattaccioli","doi":"10.23919/oceans.2009.5422406","DOIUrl":"https://doi.org/10.23919/oceans.2009.5422406","url":null,"abstract":"This paper presents a new signal processing tool: frequency warping, and its application in waveguide characterization. It can be applied in the context of signals recorded in shallow water (0–400 m) for an impulsive low-frequency source (0–200 Hz) and a single static receiver. In this configuration, propagation is described by modal theory: the recorded pressure field can be decomposed into several modes. Modes are non linear-frequency modulations which share a common frequency band. When the radial distance between source and receiver is smaller than 15 km, modes are also overlapped in time on the receiver. In this case, the recorded signal cannot be represented using classical time frequency representations and adaptive signal processing is required. Frequency warping processing transforms a give mode into a Dirac in time, using a priori information of the environment. As it is sensitive to environment mismatch, it can also be used to perform waveguide characterization. First, modal propagation is quickly reviewed. Secondly, it is shown that environment information is embedded in the time-frequency structure of the modes, but that adaptive signal processing is required to access it. Then, frequency warping processing is presented, both theoretically and experimentally. Finally, it is shown that frequency warping can be used to perform environment characterization.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127659171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Narrowband detection of acoustic source in shallow ocean using vector sensor array 基于矢量传感器阵列的浅海声源窄带探测

OCEANS 2009 Pub Date : 2009-10-26 DOI: 10.23919/OCEANS.2009.5422104

K. Krishna, G. V. Anand

引用次数: 13

Toward a platform-independent acoustic communications and navigation system for underwater vehicles 一种用于水下航行器的与平台无关的声学通信和导航系统

OCEANS 2009 Pub Date : 2009-10-26 DOI: 10.23919/OCEANS.2009.5422202

Sarah E. Webster, R. Eustice, C. Murphy, Hanumant Singhe, L. Whitcomb

引用次数: 31

Proposal for an AUV refuel station 水下航行器燃料补给站的建议

OCEANS 2009 Pub Date : 2009-10-15 DOI: 10.23919/OCEANS.2009.5422180

M. Blanco

引用次数: 0

A study on the validity of buoy mounted Acoustic Doppler profilers: A comparison of upward and downward looking systems in Onslow Bay, NC 浮标安装声学多普勒剖面仪的有效性研究:北卡罗来纳州昂斯洛湾向上和向下观测系统的比较

OCEANS 2009 Pub Date : 2009-10-01 DOI: 10.23919/OCEANS.2009.5422277

L. Locke, R. Crout

{"title":"A study on the validity of buoy mounted Acoustic Doppler profilers: A comparison of upward and downward looking systems in Onslow Bay, NC","authors":"L. Locke, R. Crout","doi":"10.23919/OCEANS.2009.5422277","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422277","url":null,"abstract":"The National Data Buoy Center (NDBC) maintains an extensive array of moored buoys around the world. Hence, mounting Acoustic Doppler Current Profilers (ADCPs) to these buoys has proven to be an avenue worth exploring. In a previous study done by Seim and Edwards [1], a downward-looking ADCP from NDBC buoy 41008 was compared to an upward-looking ADCP from the University of North Carolina at Chapel Hill (UNC) located in close proximity to test the validity of ADCP measurements made by a buoy-mounted ADCP. Since configurations of the systems were not standard, the two did not agree well. Since this time, NDBC has made several changes to the configuration of their ADCPs. This study is to again compare a NDBC downward-looking ADCP mounted to buoy 41036 to an upward-looking ADCP from the University of North Carolina at Wilmington (UNCW) mounted on the seafloor to test the reliability of NDBCs present buoy-mounted ADCP configuration. Both of these systems are located on the shallow continental shelf of Onslow Bay, North Carolina. An 18-day time series was obtained from each ADCP. Preliminary results show good agreement between the two systems. In light of the fact that the buoy-mounted system is subjected to movement by atmospheric and oceanic processes, further data conditioning is investigated to see if more precise environmental thresholds, specifically wave height thresholds, can be put in place for more accurate current measurements.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"227 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115233427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Oil spill detection technology for early warning spill prevention 溢油预警及防溢油检测技术

OCEANS 2009 Pub Date : 2009-10-01 DOI: 10.23919/OCEANS.2009.5422244

R. Mahr, C. Chase

{"title":"Oil spill detection technology for early warning spill prevention","authors":"R. Mahr, C. Chase","doi":"10.23919/OCEANS.2009.5422244","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422244","url":null,"abstract":"This paper discusses the development of an oil spill detection and alarm system that provides the marine industry with a reliable, cost-saving mechanism for containing and/or preventing accidental discharges of hydrocarbon-based pollutants. By utilizing an automated spill detection system, hydrocarbon releases are detected in real-time [analogous to a “smoke alarm” for oil spills]. Early warning and automated response capabilities allow early containment of oil pollution — thereby reducing the oil volume spilled, and minimizing damage to the environment, wildlife, public waterways and/or commercial assets. This paper details: 1] Development of a reliable, economical, optical, non-contact, UV/fluorometry-type, hydrocarbon pollution detection sensor system 2] Performance results drawn from an array of performance tests and real-world deployments, 3] A variety of existing applications and deployment opportunities for which this new technology offers a reliable solution and easy-to-use tool for both regulatory compliance and realization of cost benefits associated with minimizing spill risk[s]. Design features have evolved to reflect feedback from existing industrial users, as well as input from environmental consultants and regulatory agencies. These key system attributes include: 1] Near-zero maintenance, 2] Micron- level sensitivity for a comprehensive range of oils [from crude-oil to jet-A], and. 3] Sensor/system flexibility and adaptability for varied application requirements and a wide range of installation settings [i.e. marine, industrial, harbor, offshore, etc.]. Finally, this paper describes how any entity that produces, stores, uses, or transports hydrocarbons, can best employ the detection sensor/alarm to realize cost-benefits, strengthen compliance, and eliminate the expense, environmental damage, and bad publicity inherent with any oil spill.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"4 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121004309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

The Wave Glider: A Wave-Powered autonomous marine vehicle 波浪滑翔机:一种波浪动力的自主海上交通工具

OCEANS 2009 Pub Date : 2009-10-01 DOI: 10.23919/oceans.2009.5422129

R. Hine, S. Willcox, G. Hine, Tim Richardson

引用次数: 147

Blind DFE based on NLMS algorithm with generalized normalized gradient descent regularization 基于广义归一化梯度下降正则化NLMS算法的盲DFE

OCEANS 2009 Pub Date : 2009-10-01 DOI: 10.23919/OCEANS.2009.5422117

Abderrazak Abdaoui, C. Laot

{"title":"Blind DFE based on NLMS algorithm with generalized normalized gradient descent regularization","authors":"Abderrazak Abdaoui, C. Laot","doi":"10.23919/OCEANS.2009.5422117","DOIUrl":"https://doi.org/10.23919/OCEANS.2009.5422117","url":null,"abstract":"This paper presents robust unsupervised decision feedback equalizer (DFE) for acoustic underwater communications. The proposed equalizer consists of the cascade of four devices whose main components are recursive (7?.) and transverse (T) filters. The feature of the given equalizer is the ability to deal with severe quickly time varying channels by allowing the adjustment of both, its structure and its adaptation according to a mean square error (MSE) criterion. In the existing solution, the recursive and transverse filters are updated by decision directed least-mean-square (LMS) algorithms. However, the weakness of the LMS like algorithms against the time varying environments pushes us to improve the adaptation by the use of other robust solutions. In this paper, we propose the employ of normalized LMS algorithms with self step-size regularization based on complex-valued generalized normalized gradient descent (GNGD) method instead of simple LMS algorithms. Compared to the existent unsupervised DFE, the proposed solution gives the best performance in channel tracking despite the irregularities and the non-stationarity of the environment. Performance analysis are given in terms of the MSE for both synthetic and realistic channels obtained from underwater acoustic recorded signals.","PeriodicalId":119977,"journal":{"name":"OCEANS 2009","volume":"156 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121241876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2