Proceedings OCEANS最新文献

{"title":"Time-dependent Effects On Ridge Initiation In Sea Ice Leads","authors":"M. Coon, G.S. Knoke, P. A. Lau","doi":"10.1109/OCEANS.1989.587528","DOIUrl":"https://doi.org/10.1109/OCEANS.1989.587528","url":null,"abstract":"Recent measurements of stresses in sea ice prior to and during ridge building indicate that large stress levels may be present in the ice for several hours before ridge building actually occurs. Therefore, it may be that the time dependence (viscosity) of the lead ice which forms the ridge may be important to the ridge initiation process. This effect is investigated in this paper by considering a simple model in which the lead ice is represented by a visco-elastic beam on an elastic foundation. Elapsed time from the time of load application until creep buckling failure is determined for a range of loadings and ice elastic moduli and viscosities. These properties were obtained during the Coordinated Eastern Arctic Experiment (CEAREX). These calculations provide a framework for planning field experiments to study lead ice failure and a starting point for analysis of lead ice failure mechanisms.","PeriodicalId":331017,"journal":{"name":"Proceedings OCEANS","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115160191","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 Melville/Knorr Refit And Modernization: Capabilities For Science In The 1990's And Beyond","authors":"W. Hurley, D. H. Laible, J. Leiby","doi":"10.1109/OCEANS.1989.587099","DOIUrl":"https://doi.org/10.1109/OCEANS.1989.587099","url":null,"abstract":"The oceanographic research vessels RIV Melville and RIV Knorr were built in 1969, and although they have proved to be effective research platforms by demonstrating outstanding support to science, numerous problems have plagued and frustrated their operators and scientists. Consequently, repowering and modification studies were undertaken to redress the drawbacks of these ships. In addition, enhancements to their scientific capabilities were defined and incorporated into the project and a shipyard contract was awarded in February 1989 for their lengthening, refit and modernization. The desired capabilities for the modified vessels are significantly beyond those of the existing ships. This paper describes how these attributes were engineered into the refit. Habitability, laboratory and work spaces, storage capacities, speed and endurance, stationkeeping, maneuvering, and acoustic support improvements are discussed.","PeriodicalId":331017,"journal":{"name":"Proceedings OCEANS","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132004296","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":"A Neural Network Based Framework For Classification Of Oceanic Acoustic Signals","authors":"A. Maccato, R.J.P. de Figueii-edo","doi":"10.1109/OCEANS.1989.587491","DOIUrl":"https://doi.org/10.1109/OCEANS.1989.587491","url":null,"abstract":"This paper presents a new framework for intelligent acoustic signal processing by artificial neural networks. Problems addressed are the detection, classification, and estimation of signal parameters. The methodology consists of decomposing the above tasks into two stages. First, a highly structured, hierarchical/symbolic representation of the data is created using scale space algorithms. This calculation overcomes moderate noise and warping distortion present in the acoustic recording, and at the same time reduces the data to be processed. Second, neural network architectures are applied to the resulting symbolic structures to obtain the desired signal parameters. The use of neural network techniques allows training to be used in cases where the signals of interest are not easily characterized. Illustrations using simulated and real data will be presented. INTRODUCTION Artificial neural networks provide a new computational paradigm for solving a large class of signal recognition problems. In this paradigm, collections of elementary units called neurons work in parallel to perform a desired computational task. Each neuron performs a component of the overall calculation, and communicates its result to the other units in the network via neurosynaptic interconnections. The distinguishing characteristic of artificial neural networks, with respect to classical methods of computing, is that they can learn to perform a required calculation through training. Hence, rather than designing a procedure for computing the solution to a problem, a selection is made of a training set of exemplary input/output pairs. This is a very powerful property in problem instances for which the application data space is not characterized sufficiently well to allow explicit programming. This is often the case with oceanic acoustic signals, such as short duration transient signals resulting from spurious mechanical events in a vessel. Signal distortion caused by the water medium (amplitude and time warping effects), noise contamination, imprecise or unknown time of occurrence, and high nonstationarity are all difficulties to be confronted when trying to detect a signal, classify it, or estimate meaningful parameters of its source. Additionally, any viable algorithm for recognizing acoustic signals in real-time must possess a fast implementation and, in the case of neural nets, a relatively short training time. To this end, we propose to decompose the recognition task into two stages. The acoustic signal is first preprocessed by a numerical transformation that partially removes noise and distortion effects present in the raw data. In the second stage the resulting information is fed to a neural network for final recognition. The overall method benefits from the filtering characteristics (and possibly data reduction properties) of the first stage, and also from the learning ability of the second stage. OUTLINE O F T H E ALGORITHM To illustrate this concept, we have selected a s","PeriodicalId":331017,"journal":{"name":"Proceedings OCEANS","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130333602","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 Development Of Canada's Oceans Policy","authors":"R. W. Crowley, R. C. Bourgeois","doi":"10.1109/OCEANS.1989.592852","DOIUrl":"https://doi.org/10.1109/OCEANS.1989.592852","url":null,"abstract":"THE DEVELOPMENT OF CANADA'S OCEANS POLICY Ronald W. Crowley and Raymond C. Bourgeois Economic and Commercial Analysis Directorate Department of Fisheries and Oceans 200 Kent Street Ottawa, Ontario K1A OE6 Cnnndn ndopted a new National Oceans Policy in 1987. This policy was the result of boUi domestic and intemational forces. The rintion's peogrnphy, its existing oceans research capability nnd govemment priorities all converged in nntional focus in the mid-1980's. Canada's pivotal role in UNCLOS JII and the 1982 Law of the Sea Convention, and the U.S. challenge to its sovetcignty over the Northwest Pnssage, were also key. Tliis paper assesses the process by wliicli this policy was developed and identifies key considedons that led to its pmmulgntion. Policy development theory and policy models are exnniined with a view to determining the extent to which the developnient of Cnnadn's National Oceans Policy meets their criterii. ?he process lending to the Policy involved extensive consultations with many interests. How these consultations affected the final policy is reviewed. Tie paper cwcliitles with comments an the usefiilness of policy pmcess nidels and with a review of' lessons leanled.","PeriodicalId":331017,"journal":{"name":"Proceedings OCEANS","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125584838","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":"Acoustic Positioning Using Multielement Array","authors":"A. Zielinski, Lixue Wu","doi":"10.1109/OCEANS.1989.587489","DOIUrl":"https://doi.org/10.1109/OCEANS.1989.587489","url":null,"abstract":"With these assumptions, problem of estimating the arrival angle of a plane wave at linear array is analogous to that encountered in spectral analysis. The well known applicable methods are maximum likelihood estimation [l], adaptive arrays [ 2 ] , maximum entropy estimation [3], and wavenumber spectral estimation [4]. This paper aims to give a straightforward real-time treatment of this estimation problem. A discrete Fourier transform (DFT) algorithm is employed. A chirp z-transform (CZT) algorithm and employment of two frequencies are suggested to improve the system resolution. The incident signals arriving from direction 0 are received by N (even) nondirectional, point sensors arranged along a straight line. If the acoustic pressure received by each sensor is simultaneously sampled at time t = t o and the samples are subjected to the discrete Fourier transform (DFT), we obtain the power-normalized beam pattern given by [5]","PeriodicalId":331017,"journal":{"name":"Proceedings OCEANS","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125022893","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":"Ecological Monitoring At The Texas Flower Garden Coral Reefs","authors":"S. Gittings, K. Deslarzes, G. Boland, T. J. Bright","doi":"10.1109/OCEANS.1989.592815","DOIUrl":"https://doi.org/10.1109/OCEANS.1989.592815","url":null,"abstract":"","PeriodicalId":331017,"journal":{"name":"Proceedings OCEANS","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134280698","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 Autonomous Conductivity-Temperture Vehicle: First in the Seashuttle Family of Autonomous Underwater Vehicle's for Scientific Payloads","authors":"R. Light, J. Morison","doi":"10.1109/OCEANS.1989.586683","DOIUrl":"https://doi.org/10.1109/OCEANS.1989.586683","url":null,"abstract":"The Mark 38 miniature, mobile, sonar target, originally developed for the Navy in 1973 as an expendable training aid for sonar operators, has been redesigned and reconfigured as a robotic underwater vehicle to carry scientific instruments for ocean research. The basic vehicle, named the SEASI-IUTTLE, is nominally 132 cm long, 8.9 cm in diameter and houses a microprocessor controlled guidance system that allows the vehicle to actively position its elevators and rudders in response to data from heading, pitch, roll, and pressure sensors. The vehicle can be programmed to follow complicated prescribed courses of action in five modes of operation: launch, mission, recovery, homing and homing search. It has a nominal speed of 4 kts, an endurance of 2 hrs, and depth tolerance to 250m. The vehicle is equipped with a homing system that returns it to an acoustic beacon, usually deployed at its launch point, at the end of its mission. The SEASHUTTLE provides power and control via a serial interface for instrumentation packages. The SEASHUTTLE has been fitted with a SeaBird CTD for measurements beneath the Arctic ice pack.","PeriodicalId":331017,"journal":{"name":"Proceedings OCEANS","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134548883","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":"Light Weight, Low Cost Work Platform","authors":"P. Yinger, D.S. Schiefen","doi":"10.1109/OCEANS.1989.586676","DOIUrl":"https://doi.org/10.1109/OCEANS.1989.586676","url":null,"abstract":"Using divers or large ROVs and their associated tracking and support systems can be costly from a success as well as a price standpoint. The time and money required to mobilize a diving or large ROV effort can defeat a project before it begins. There are alternatives; SAIC/MariPro has assembled a highly versatile light weight, low cost ROV and tracking system combination. It is capable of performing many tasks previously reserved for divers and large ROVs. Attaching a recovery line into a 4-inch diameter eye on a package in 700 feet of water is one recent example of the use of this system. Additionally, projects have been undertaken to locate and navigate to Benthos acoustic releases and expendable transponders. Surveying anchor moorings and bottom-moored equipment have also been tasks performed by SAIC/MariPro's two Phantom HD2/Trackpoint I1 tracking systems. Future projects include gathering bottom samples, surveying deployed cable systems, inspection components, and recovering equipment in harsh and/or dangerous environments. Each project attempted by this system has been completed at reduced cost to the customer in both dollars and time. A great deal of information has been gathered on how to operate ROVs and low frequency (from 8-15 kHz) tracking systems. Recovery hooks, underslung densewound cable packs, and releasable descent weights are a few of the accessories SAIC/MariPro has successfully integrated into its system. Divers and large ROVs will never be replaced entirely, but the assembled system will serve to make many tasks more feasible.","PeriodicalId":331017,"journal":{"name":"Proceedings OCEANS","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132061309","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":"Eastern Arctic Ambient Noise","authors":"R. Pritchard","doi":"10.1109/OCEANS.1989.587517","DOIUrl":"https://doi.org/10.1109/OCEANS.1989.587517","url":null,"abstract":"","PeriodicalId":331017,"journal":{"name":"Proceedings OCEANS","volume":"124 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133740600","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":"Recovery Of Santa Monica Bay From Sludge Discharge: Progress Report","authors":"B. Thompson, J. Dorsey","doi":"10.1109/OCEANS.1989.586757","DOIUrl":"https://doi.org/10.1109/OCEANS.1989.586757","url":null,"abstract":"A multidisciplinary study (Table 1) was designed that included preand post-termination sampling near the outfall and at a reference (control) area (42) (Fig. 1). Pre-termination sampling began in February 1986 and included three sampling periods over 1.5 years. Sampling was conducted quarterly during the first year after termination (1988) as we anticipated rapid recovery. Sampling will continue semi-annually through summer 1990, a five-year study.","PeriodicalId":331017,"journal":{"name":"Proceedings OCEANS","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133774892","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}