Europe Oceans 2005最新文献

{"title":"Maximum likelihood estimates of a spread-spectrum source position using a tetrahedral ultra-short baseline array","authors":"P. Beaujean, A. I. Mohamed, R. Warin","doi":"10.1109/OCEANSE.2005.1511699","DOIUrl":"https://doi.org/10.1109/OCEANSE.2005.1511699","url":null,"abstract":"An ultra-short baseline acoustic positioning system has been made compatible with the FAU Dual Purpose Acoustic Modem network to provide azimuth and elevation of modem-type sources. The acoustic antenna is composed of four transducers arranged as a tetrahedron. The position estimation is performed using the detection sequence of each message transmitted by the modem source. This spread-spectrum detection sequence is a series of frequency-hopped pulses. The estimation technique is based on the maximum-likelihood estimation technique originally described by Quazi and Lerro. A simulation has been implemented and experiments have been performed in a calibration tank specifically built for this purpose. Model and experiments confirm that the accuracy of this system improves with the number of pulses and the signal-to-noise ratio, and that a high positioning accuracy can be achieved using the proposed method. This work is sponsored in part by the Office of Naval Research, Code # ONR 321OM, Dr. Tom Swean.","PeriodicalId":120840,"journal":{"name":"Europe Oceans 2005","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130464267","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}

{"title":"The Litto3D project","authors":"L. Louvart, C. Grateau","doi":"10.1109/OCEANSE.2005.1513237","DOIUrl":"https://doi.org/10.1109/OCEANSE.2005.1513237","url":null,"abstract":"In 2003 the French Institut Geographique National (IGN) and Service Hydrographique et Oceanographique de la Marine (SHOM) have been tasked by the Prime Minister to join efforts to produce together a seamless, modern, precise topographic and bathymetric model, including possibly the tides, of the entire French coasts. The area envisaged should extend from the 10 metres contour line inland to the distance of 10 kilometres seaward, or 6 nautical miles from the coastal baselines. This project was created to meet hundred or more requirements expressed by coastal managers concerned by the protection and exploitation of the littoral and by users of geo-referenced data; it should become the core of all future integrated coastal management projects. The preliminary study conducted in the Golfe du Morbihan, Southern Brittany, has already proven that France should be spared the strenuous geodetic problems met elsewhere. Thanks to the Napoleonic tradition of keeping common geodetic references inland and at sea, the historical database \"Histolitt\" could be assembled fairly quickly, leaving in the poorly surveyed areas gaps that could be filled efficiently by modern technologies (laser bathymetry and topography, MBES, RTK, aerial orthophotos, permanent digital tide gauges), allowing metric accuracy on the plane and decimetric precision of heights and depths. A first lidar survey has already been planned in the summer of 2005 in the Golfe du Morbihan to conduct further tests and generate a precise Digital Terrain Model (DTM) at different resolutions (2 /spl times/ 2 m and 4 /spl times/ 4 m). The survey strategy comprises three different approaches, depending on the bathymetric interest, the near shore seabed complexity and the Rapid Environment Assessment military program requirements.","PeriodicalId":120840,"journal":{"name":"Europe Oceans 2005","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134376221","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}

{"title":"Simulation-based ship design","authors":"V. Bertram, G. Thiart","doi":"10.1109/OCEANSE.2005.1511693","DOIUrl":"https://doi.org/10.1109/OCEANSE.2005.1511693","url":null,"abstract":"Ship design changes from experience-based design to first-principle, simulation-based design. The scope of analyses in modern ship design is demonstrated showing industrial and recent research applications, not only in classical structural and fluid mechanics, but also in discrete event simulations as applied in cargo handling and ship evacuations. The state of the art is reviewed pointing out remaining limitations in current models and research trends. Classical stand-alone analyses are increasingly interfaced and integrated, employing on occasion also Virtual Reality techniques. Several examples are given to illustrate the process.","PeriodicalId":120840,"journal":{"name":"Europe Oceans 2005","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133395055","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}

{"title":"Sea surface slicks characterization in SAR images","authors":"T. Kanaa, G. Mercier, E. Tonyé","doi":"10.1109/OCEANSE.2005.1511797","DOIUrl":"https://doi.org/10.1109/OCEANSE.2005.1511797","url":null,"abstract":"The authors present a new method to characterise and discriminate oil slicks and some look-alikes in ERS-2 SAR images according only to the observed sea roughness, to reduce oil spill detection and monitoring systems cost. It exploits sea wave spectrum images from the multiscale analysis based on a modified morphological pyramid. Many backscatter characteristics extracted at each level, depended on object and background features are normalized to make its spectral scales be identical. Twenty objects (spot and border) backscatter features have been measured. Eleven sea surface slicks types have been analysed, namely oil, atmospheric instability, wind front, unstable air-mass, current front, falling land wind, large gravity waves, low wind area, natural slicks, swell visible and wind sheltered area. The results presented as smoothed basic profiles and textural spectra allow to tackle oil slicks supervised classification in new images. Oil slicks and current front are discriminated. But, some ambiguities of slicks discrimination in SAR images remain persistent.","PeriodicalId":120840,"journal":{"name":"Europe Oceans 2005","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133881218","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}

{"title":"On the furtivity of signals used in oceanic acoustic tomography experiments","authors":"O. Rabaste, T. Chonavel","doi":"10.1109/OCEANSE.2005.1513191","DOIUrl":"https://doi.org/10.1109/OCEANSE.2005.1513191","url":null,"abstract":"In this paper, the furtivity of acoustic signals commonly used in oceanic acoustic tomography experiments is addressed. Three kinds of detectors are presented that can be used by an outsider to detect either unknown signals or signals showing the main characteristics of common tomographic signals. In the first case, the detector decision statistic is based on the signals energy, whereas in the second case it exploits either cyclostationarity properties of the signals or their time-frequency characteristics. Performance of these detectors on signals transmitted through a multipath underwater channel is studied.","PeriodicalId":120840,"journal":{"name":"Europe Oceans 2005","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122616156","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}

{"title":"Design of networking protocols for shallow water peer-to-peer acoustic networks","authors":"S. Shahabudeen, M. Chitre","doi":"10.1109/OCEANSE.2005.1511787","DOIUrl":"https://doi.org/10.1109/OCEANSE.2005.1511787","url":null,"abstract":"Communication between a set of underwater systems such as remote sensors, autonomous underwater vehicles and control vessels would enhance the effective use of such systems tremendously. As electromagnetic waves do not propagate well underwater, acoustics plays a key role in underwater communication. Although point-to-point acoustic links can be established via numerous modulation schemes, an acoustic communication network demands multiuser communication. In such an environment, orthogonal modulation schemes could provide a solution for multiple simultaneous acoustic links. As an alternative to orthogonal schemes, random shared access technology has proven successful in many wireless networks. Through numerical simulations, we compare the performance of orthogonal and random shared access for underwater networking. Over the past few decades, numerous networking protocols have been developed for use in wired and wireless networks. Due to significant differences in the characteristics of electromagnetic and acoustic channels, these networking protocols require modifications to perform well in underwater networks. As sound waves are much slower than electromagnetic waves, the latency in communication is typically much higher. Due to the multipath propagation and ambient noise, the effective data rates are lower and packet loss is much greater. In this paper, we simulate variants of some popular protocols for underwater use, focusing on the Physical and Datalink layers of the OSI protocol stack. The aim is to select an appropriate Physical Layer and Datalink Layer model for a small underwater network to be implemented.","PeriodicalId":120840,"journal":{"name":"Europe Oceans 2005","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122962385","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}

{"title":"Hydrothermal vents: a novel theory of illumination","authors":"D. J. Bogorff","doi":"10.1109/OCEANSE.2005.1511684","DOIUrl":"https://doi.org/10.1109/OCEANSE.2005.1511684","url":null,"abstract":"There are many theories revolving around the source of non-thermally based visible light emissions from deep-sea hydrothermal vents. Although many of these theories have been proven possible in a controlled laboratory environment, none have been directly linked to hydrothermal vents through on-site experimentation and evaluation. Nor have any of them conclusively lain to rest the unanswerable and unpredictable source and exact circumstances of this mysterious light. Visible light has been shown to occur in larger than background concentrations intermittently at both black smokers and beehives, in the presence and absence of mineral emissions, and just above and below vent openings. This behavior cannot be explained by crystalloluminescence, triboluminescence, or even chemiluminescence where illumination is dependent on specific physical characteristics of the vent which cannot guarantee the presence or absence of visible light anomalies. These theories are also not restricted to just the vent openings, as many of the physical requirements occur beyond the vent and, in some cases, into the plume. A novel theory of hydrothermal vent illumination by way of amplified C/spl caron/erenkov radiation through internal plume reflection will be presented. This theory includes the already known creation of visible light by muons in seawater created by the bombardment of the Earth by extraterrestrial neutrinos. When these particles enter seawater directly or through collision, they produce a lagging wave of visible light known as C/spl caron/erenkov radiation. This lagging wave, like normal visible light, can be trapped and magnified, as in C/spl caron/erenkov radiation detectors. The large variation in density between exiting plume emission and surrounding seawater may be enough to trap visible light within the base of the plume itself making the visible light from C/spl caron/erenkov radiation appear to be brighter than the surrounding seawater. The variation and unpredictability of extraterrestrial muons in the deep ocean may help account for the appearance, disappearance, and reappearance of light at some hydrothermal vents. It would also help explain the presence of illumination in a variety of hydrothermal vents and differing plume emission. Taking known data and theory from actual visits to deep sea hydrothermal vents combined with known data of present theories of illumination and experimentation, a composite holistic view of this quandary will be evaluated, and a theoretical written model will be composed. This new theory hopes to satisfy data obtained on-site at the hydrothermal vents by previous study, as well as attempt to bring some sort of closure to the unpredictable and mysterious question of hydrothermal vent illumination.","PeriodicalId":120840,"journal":{"name":"Europe Oceans 2005","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127922862","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}

{"title":"Artificial intelligence for low-crew ships","authors":"Volker Bertram","doi":"10.1109/OCEANSE.2005.1511692","DOIUrl":"https://doi.org/10.1109/OCEANSE.2005.1511692","url":null,"abstract":"An overview of techniques, collectively grouped under the label 'artificial intelligence', for low-crew or even unmanned ships is given with special focus on navy ships. Knowledge-based systems, machine vision, speech and gesture interpretation, distributed intelligence are discussed with recent research applications worldwide given to illustrate progress and problems in implementing these techniques to ships.","PeriodicalId":120840,"journal":{"name":"Europe Oceans 2005","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121400677","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}

{"title":"Results from a hybrid synthetic aperture sonar motion estimation scheme","authors":"D. A. Cook, John, Stroud, Jose E. Fernandez, D. Lathrop","doi":"10.1109/OCEANSE.2005.1513261","DOIUrl":"https://doi.org/10.1109/OCEANSE.2005.1513261","url":null,"abstract":"Synthetic aperture sonar (SAS) is used to produce high-quality side-scan imagery of the sea floor in which the along-track resolution is constant with range. SAS sensor technology is transitioning from towed vehicles toward more versatile autonomous underwater vehicles (AUVs). Experience to date has shown that the 21-inch AUVs tend to be less stable than the longer towed vehicle of the same diameter used during the U.S. Navy's initial SAS technology demo efforts. The corresponding increase in undesirable motion of the AUV platform carrying the sonar has motivated the development of a new generation of motion estimation and compensation schemes. This paper describes the results obtained from one such motion estimation method applied to the U.S. Navy's SAS21/Reliant SAS system. The data set used for evaluating the image improvement consists of 31 km of track taken at the 2004 Combined Joint Task Force Exercise (CJTFEX-04) off the North Carolina coast. The motion estimation combines the angular velocity information provided from an inertial navigation unit with the traditional redundant phase center approach in order to accurately estimate the ping-to-ping translation of the SAS array. This approach consistently yields better imagery compared to the previously-used technique.","PeriodicalId":120840,"journal":{"name":"Europe Oceans 2005","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128947476","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}

{"title":"Shallow angle LIDAR for wave measurement","authors":"J. Horwood, R. Thurley, M. Belmont, J. Baker","doi":"10.1109/OCEANSE.2005.1513221","DOIUrl":"https://doi.org/10.1109/OCEANSE.2005.1513221","url":null,"abstract":"The Exeter University Marine Dynamics Group has developed a shallow angle LIDAR for wave measurement purposes. This paper introduces the system and illustrates some metrology issues specific to this method. The LIDAR system uses a 532 nm (green) Q switched, high repetition rate, nanosecond pulsed laser. The system is designed to be scanned along a line or over an area. A 100 point square plot requires typically 0.5 seconds to complete. Whereas fixed-wing airborne LIDAR is continuously moving, the system described here is mounted in a fixed position and it is therefore possible to record sea surface shape and wave evolution over time. A plot comprises a set of surface elevation measurements determined by a combination of time of flight and high precision angle measurement. Unlike airborne LIDAR systems, the system is fitted to a shore or vessel mounted platform (with motion compensation in the case of vessel mounting) and the incident beam typically makes an angle with the sea surface of less than 10 degrees. The signal returns from airborne LIDARs, at approximately normal incidence, are strong compared to the very weak returns from the shallow angle system described in this paper. This fact has previously inhibited the development of such shallow angle systems. Some features of this system which make it viable are: a minimum field of view optical system, a very short pulse length high repetition rate laser system, an ultra high resolution beam scanner and what is effectively a one-dimensional image processing style coherent hybrid detection system operating with GHz data rates. The use of 532nm wavelength allows the scattering of light from calcareous plankton particles as well as other suspended particles and foam or aeration. The different nature of the light scattering from suspended particles or from foam or highly aerated water also allows the qualitative identification of breaking or foaming waves. The paper presents recordings of the real-time evolution of spatially resolved wave profile data obtained using this system. The shallow angle LIDAR system is shown to offer significant advantages over existing methods for wave measurement such as wavebuoys, wavestaffs, acoustic Doppler and radar, both in terms of the precision of the data returned and in the flexibility of deployment. Examples are presented of both near-shore and offshore applications. This system is one of the very few techniques capable of returning spatially resolved 'wave videos'. Another important feature of the new system for near-shore applications is that it avoids the vulnerability to damage of systems mounted in the surf and swash zones. The system can be installed at any state of the tide with no requirement to undertake installation work below the high water mark. The system is shown to be an ideal choice for most types of wave measurement applications and is eminently suited to the most extreme sea conditions. It is shown to be a portable remote sensing system capab","PeriodicalId":120840,"journal":{"name":"Europe Oceans 2005","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129336555","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}