中国会展最新文献_第4页

A cross-platform microstructure turbulence measurement package 跨平台微结构湍流测量包

中国会展 Pub Date : 2000-09-11 DOI: 10.1109/OCEANS.2000.882256

K. Holappa, M. Dhanak

{"title":"A cross-platform microstructure turbulence measurement package","authors":"K. Holappa, M. Dhanak","doi":"10.1109/OCEANS.2000.882256","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.882256","url":null,"abstract":"Ambient turbulence in the ocean is responsible for dissipating the kinetic energy in the ocean at very small scales. Small autonomous underwater vehicles (AUVs) provide versatile mobile platforms for surveying a shallow water coastal environment at low operational costs. The platforms are uncoupled from the low frequency vibrations associated with platforms towed from surface ships. Measurement of turbulent microstructure and the associated dissipation rate using an AUV requires accommodation of the inherent vibration characteristics of a self-propelled platform. Often such vibrations are in the range of flow measurements of interest and may corrupt the data. At Florida Atlantic University, a turbulence measurement package has been developed which implements vibration isolation from the AUV platform. The sensors in the package include two shear probes, a fast response temperature probe, a fast response conductivity probe and accelerometers for monitoring vibrations. In addition, the turbulence package developed is modular and interoperable in the sense that it may be mounted on a variety of platforms in a simple robust fashion without changes to the platform. The AUV platforms used thus far include the Ocean Explorer vehicle at Florida Atlantic University and the Autosub at the Southampton Oceanography Center. These vehicles vary in size from 2 meters long and under 200 kg for the OEX to over 7 meters long and over 1500 kg for the Autosub. The design of the turbulence package and results from implementation aboard these very different autonomous underwater vehicles are described.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"29 1","pages":"2177-2183 vol.3"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78141901","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: 0

Results from recent GPS Tides Projects 最近GPS潮汐项目的结果

中国会展 Pub Date : 2000-09-11 DOI: 10.1109/OCEANS.2000.881759

B. Shannon, J. Hubbard

{"title":"Results from recent GPS Tides Projects","authors":"B. Shannon, J. Hubbard","doi":"10.1109/OCEANS.2000.881759","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.881759","url":null,"abstract":"The U.S. Army Corps of Engineers (USACE) has completed tidal datum elevation models using Differential Global Positioning System (DGPS) carrier phase methods in three ocean approach channels in the southeastern United States. These channels are all contained entirely or in part within the state of Georgia. Tide observations and tidal datum determinations were coordinated with the Center for Operational Oceanographic Products and Services (COOPS), National Oceanic and Atmospheric Administration NOAA. The datum elevation models confirms that the local mean sea level and the mean tide level differ by a small amount on the open coast and shows that the sea level is approximately an equipotential surface over a large area of the Georgia coastline. The survey results also show an anomalous depression in mean lower low water offshore, which may be due to DGPS limitations when using a 20 km baseline distance. The USACE has found the use of carrier phase DGPS and tidal datum models a useful method for maintaining vertical control for dredging operations and intends to use carrier phase DGPS for projects along the entire east coast of the United States. The paper discusses the experiences in three projects: Ferandina, Florida, and north to Brunswick, Georgia and Savannah, Georgia. The large range light towers on the approach to Fernandina with installed acoustic tide gauges provided vertical datum references for the GPS Tides Project, which enabled the offshore GPS measurement results to be bounded. The GPS Tides measurements in Georgia were unbounded; however, the mean tide levels are correlated with the Florida results.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"35 1","pages":"1159-1174 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75115957","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

A broadband hybrid magnetostrictive/piezoelectric transducer array 一种宽带混合磁致伸缩/压电换能器阵列

中国会展 Pub Date : 2000-09-11 DOI: 10.1109/OCEANS.2000.881812

S. Butler, F. Tito

引用次数: 27

Optimized image sequence analysis for real-time underwater cable tracking 优化的水下电缆实时跟踪图像序列分析

中国会展 Pub Date : 2000-09-11 DOI: 10.1109/OCEANS.2000.881305

M. Simo, A. Ortiz, G. Oliver

{"title":"Optimized image sequence analysis for real-time underwater cable tracking","authors":"M. Simo, A. Ortiz, G. Oliver","doi":"10.1109/OCEANS.2000.881305","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.881305","url":null,"abstract":"Nowadays, the surveillance and inspection of underwater installations, such as power and telecommunication cables and pipelines, is carried out by operators that, being on the surface, drive a ROV with cameras mounted over it. This is a tedious and high time-consuming task, easily prone to errors mainly because of loss of attention or fatigue of the human operator. Besides, the complexity of the task is increased by the lack of quality of typical seabed images, which are mainly characterised by blurring, nonuniform illumination, lack of contrast and instability in the vehicle motion. In this study, the development of a vision system guiding an AUV able to detect and track automatically an underwater power cable laid on the seabed has been the main concern. The vision system that is proposed is able to track the cable with an average success rate above 90% while maintaining real-time performance. The system has been tested using sequences coming from a video tape obtained in several tracking sessions of various real cables with a ROV driven from the surface. These cables were installed several years ago, so that the images do not present highly contrasted cables over a sandy seabed; on the contrary, these cables are partially covered in algae or sand, and are surrounded by other algae and rocks, making thus the sequences highly realistic.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"5 1","pages":"497-504 vol.1"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74938436","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

Control system applications in wave energy conversion 控制系统在波浪能转换中的应用

中国会展 Pub Date : 2000-09-11 DOI: 10.1109/OCEANS.2000.882202

U. Korde

引用次数: 64

High-rate acoustic communications for ocean observatories-performance testing over a 3000 m vertical path 用于海洋观测站的高速率声学通信-在3000米垂直路径上的性能测试

中国会展 Pub Date : 2000-09-11 DOI: 10.1109/OCEANS.2000.881807

Lee Freitag, Johnson, Dan Frye

{"title":"High-rate acoustic communications for ocean observatories-performance testing over a 3000 m vertical path","authors":"Lee Freitag, Johnson, Dan Frye","doi":"10.1109/OCEANS.2000.881807","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.881807","url":null,"abstract":"The viability of acoustically-linked, long-term ocean sensing is dependent on the power efficiency of the communications system. Energy storage in the deep ocean remains costly despite advances in battery technology, and thus, maximizing data throughput at constant power is an important goal. In preparation for future deep-water applications, a test was previously conducted in 3000 m water to measure the performance of a communications system using a number of different signaling techniques. The signals included BPSK, QPSK and 8-PSK modulation with data rates up to 15000 bits per second. Several receivers were used, including directional transducers, both baffled and un-baffled, as well as a small omnidirectional array. Reliable communication at up to 15000 bps using 7.5 W at the transmitter was achieved. The baffled directional receiver offered the best performance, while the omni-directional array provided approximately 50% less throughput. Source-receiver motion was found to impact system performance and results using an improved Doppler tracking and compensation method are described. Details of the results using various modulation methods and receiver combinations are discussed and their performance extrapolated to full-ocean depth as an aid to the design of future ocean observatory links.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"1 1","pages":"1443-1448 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74675177","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: 20

Computer vision in AUVs: automatic roto-rectification of stereo images auv中的计算机视觉:立体图像的自动旋转校正

中国会展 Pub Date : 2000-09-11 DOI: 10.1109/OCEANS.2000.882255

J. Zelasco, D. A. Dagum, J. Donayo, T. Arcomano

{"title":"Computer vision in AUVs: automatic roto-rectification of stereo images","authors":"J. Zelasco, D. A. Dagum, J. Donayo, T. Arcomano","doi":"10.1109/OCEANS.2000.882255","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.882255","url":null,"abstract":"This work has been developed in the framework of a project of stereo vision for autonomous underwater vehicles (AUVs) provided with optical sensors. To obtain a numerical model of an underwater scene of more precision than the one that would be obtained starting from a couple of simultaneous images, we should re-calculate starting from two images taken in consecutive way. The increase of the distance among the points of view would improve this precision. Normally, in consecutive exposures, the lines of bitmaps do not coincide with the epipolar lines as in case of simultaneous images from calibrated sensors. This complicates the search of homologous points. Parameters of relative rotation and translation of two consecutive images are approximately known. To know them with more accuracy allows us to carry out the image roto-rectification and to use the results. Obtaining knowledge of a certain number of couples of homologous points, we can calculate with enough precision the relative rotation parameters in order to proceed with image roto-rectification, obtaining a new image couple where epipolar lines match with bitmap lines. This involves three major steps. The first one concerns the obtention of relative orientation among components of a stereo couple. This relative orientation is then used to find an optimal plane to minimize deformation when projecting images. Finally, the projection itself of the couple over an optimal plane is found. Then, it is possible to apply the 3D reconstruction process. In conclusion, given any stereo pair of images, the whole process of 3-D numeric model obtention can be automated.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"11 1","pages":"2169-2176 vol.3"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74800051","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: 6

HMS Scott-United Kingdom ocean survey ship 英国皇家海军斯科特号海洋调查船

中国会展 Pub Date : 2000-09-11 DOI: 10.1109/OCEANS.2000.881724

F. Pappalardi, S. Dunham, M. Leblang

{"title":"HMS Scott-United Kingdom ocean survey ship","authors":"F. Pappalardi, S. Dunham, M. Leblang","doi":"10.1109/OCEANS.2000.881724","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.881724","url":null,"abstract":"Minimizing the cost per survey mile while insuring that survey products meet required standards is a prime consideration when evaluating oceanographic surveying systems. This was one of the prime factors that led to the United Kingdom Ministry of Defense Procurement Executive (UK MOD PE) selection of a U.S. Navy designed ocean survey system to be installed aboard a new construction ship. The 13500 ton HMS SCOTT was designed and built specifically to accommodate the U.S. Survey system and is considered the UK's premier survey ship, conducting survey operations lasting 30 days or more and spending approximately 300 days at sea each year. The mission of HMS SCOTT is to gather, process and record time-correlated bathymetric, gravity, magnetic and other oceanographic data as a function of latitude and longitude. The survey system used to accomplish the bathymetric data gathering portion of their mission is composed of three major subsystems; Navigation, Sonar and Mission Control and Processing. These subsystems are supported by a dedicated regulated power system. The Navigation Subsystem provides precise and accurate platform attitude, position and velocity. The Sonar Subsystem provides both multi-beam, wide swath (120 degree coverage) and single beam derived depth data which is correlated with precise time-tagged position information. The Mission Control and Processing (MCAP) Subsystem provides centralized control and performance monitoring of overall survey system operation. Since deployment in early 1998, HMS SCOTT has successfully conducted highly accurate bathymetric surveys at an average sustained speed of 12 knots in ocean depths ranging from 50 fathoms to approximately 2500 fathoms in various types of terrain, from flat to very high relief.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"11 1","pages":"961-967 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73027537","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

Computer aided detection/computer aided classification and data fusion algorithms for automated detection and classification of underwater mines 水下水雷自动探测与分类的计算机辅助探测/计算机辅助分类与数据融合算法

中国会展 Pub Date : 2000-09-11 DOI: 10.1109/OCEANS.2000.881273

C. Ciany, Jim Huang

{"title":"Computer aided detection/computer aided classification and data fusion algorithms for automated detection and classification of underwater mines","authors":"C. Ciany, Jim Huang","doi":"10.1109/OCEANS.2000.881273","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.881273","url":null,"abstract":"Raytheon has successfully developed a computer-aided detection/computer aided classification (CAD/CAC) algorithm to process the sidescan sonar outputs of both the AN/AQS20 helicopter-towed minehunting system and Woods Hole Oceanographic Institute's (WHOI) Remote Environmental Monitoring UnitS (REMUS) unmanned underwater vehicle. These systems employ high frequency acoustic imaging sonars to detect, classify, and localize minelike objects on the ocean bottom. The algorithm was initially demonstrated at the Coastal System Station (CSS) underwater range in Panama City, Florida, and then applied to REMUS sonar imagery taken in the Very Shallow Water (VSW) environment off the coast of San Diego, California. A data fusion technique for combining the outputs of three different CAD/CAC algorithms was subsequently developed and applied to a set of REMUS data. The fusion demonstrated a 4:1 reduction in false alarms relative to any single CAD/CAC algorithm. This paper gives overviews of the AN/AQS30 and the REMUS systems, describes the Raytheon CAD/CAC and Data Fusion algorithms, and gives sample results from processing of the sea test data.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"27 1","pages":"277-284 vol.1"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73757229","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: 38

Geocoding sidescan sonar data-an inverse problem 对侧扫描声纳数据进行地理编码是一个逆向问题

中国会展 Pub Date : 2000-09-11 DOI: 10.1109/OCEANS.2000.881228

J. A. Fawcett

引用次数: 0