中国会展最新文献

{"title":"Multi-aspect synthetic aperture sonar","authors":"Jose E. Fernandez, J. Christoff","doi":"10.1109/OCEANS.2000.881256","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.881256","url":null,"abstract":"Multi-aspect or multi-look processing is known to improve the image quality and target detection capability of high resolution synthetic aperture sonar (SAS) imaging systems. We present in this paper a brief description on the topic and typical results obtained from sea data collected while fielding the High Frequency/Low Frequency Synthetic Aperture Sonar (HF/LFSAS).","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"71 1","pages":"177-180 vol.1"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79326480","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":"Circulation and pollutant transport modeling in Narragansett Bay","authors":"C. Swanson, D. Mendelsohn, M. Ward","doi":"10.1109/OCEANS.2000.882184","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.882184","url":null,"abstract":"Powerful PCs have made possible the efficient use of sophisticated two- and three-dimensional modeling techniques that were previously available to modelers only in a research environment. Applied Science Associates, Inc. has been very active in the development of such models in the PC environment. This effort includes application of hydrodynamics, pollutant transport and water quality models to specific environmental problems in Narragansett Bay. They have been used to simulate the effects of combined sewer overflows in the Providence River and upper Narragansett Bay; thermal effluent in Mt. Hope Bay from the Brayton Point Station electrical generating facility; and dredging and dredged material disposal operations; among others. These examples highlight what the authors have learned about bay circulation and pollutant transport and the use of numerical modeling to help assess the environmental conditions in the bay today and in the future.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"1 1","pages":"1695-1701 vol.3"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83329464","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":"Automated matched-field tracking in shallow water 2000 IEEE international symposium","authors":"P. Baxley, R. Brannan","doi":"10.1109/OCEANS.2000.881369","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.881369","url":null,"abstract":"Matched-field tracking (MFT) is the application of matched-field processing (MFP) to a moving source. This involves either post-processing MFP outputs to detect tracks of target peaks, or generalizing the search space of the processor to include candidate source tracks. The latter approach, referred to as automated MFT, is examined in this paper. By integrating matched-field correlations over candidate source tracks, the true track can be detected (as determined by the highest integrated correlation) and the target track parameters estimated. In addition, the integration process results in a gain in detectibility for the true source track. For the general case of a source moving in three-dimensions through an environment which varies in three dimensions, the technique is computationally restrictive, because of the large number search parameters. However, for a vertical line array (VLA) in a range-independent environment, and an assumption of constant-depth, constant range-rate tracks, the search space is reduced to the range and depth at the beginning (or end) of the track, and the range-rate. The integration process can then be performed by a simple shift-then-average scheme applied to range-depth ambiguity-surface time samples. For a constant-velocity source, the range-rate can generally be assumed to be constant, except for a period in which it passes through the closest-point-of-approach (CPA). For that case, a CPA estimator, which attempts to match data from a moving source with that expected for candidate CPA tracks, is implemented. For horizontal line arrays (HLAs), a hybrid planewave beamforming/matched-field processing, track-before-detect (TBD) technique, which takes advantage of the azimuthal-filtering capability of HLAs to limit the bearing search, may be used. This approach provides estimates of the full track parameters (range, depth, course, and speed) with a processing load substantially lower than that required for a fully three-dimensional MFP search. These techniques are applied to experimental tonal data collected on a VLA and HLA during the 1996 Shallow Water Evaluation Cell Experiment (SWellEX-96), which occurred in 200-m water, 6 km southwest of San Diego.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"75 1","pages":"869-875 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80935844","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":"Approximate CFAR signal detection in strong low rank non-Gaussian interference","authors":"I. Kirsteins, M. Rangaswamy","doi":"10.1109/OCEANS.2000.881784","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.881784","url":null,"abstract":"We have devised a new generalized likelihood ratio test for detecting a signal in unknown, strong non-Gaussian low rank interference plus white Gaussian noise which needs no knowledge of the non-Gaussian distribution. From perturbation expansions of the test statistic, we establish the connection of the proposed GLRT detector to the UMPI test and show that it is approximately CFAR. Computer simulations indicate that the new detector significantly outperforms traditional adaptive methods in non-Gaussian interference.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"7 1","pages":"1305-1308 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90297779","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 nearshore geophysical survey for offshore minerals, southwestern Sri Lanka","authors":"G. Sonnichsen, J. Lewis, N. P. Wijayananda, G. A. Nooten","doi":"10.1109/OCEANS.2000.882171","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.882171","url":null,"abstract":"In 1997, the Geological Survey of Canada (Atlantic) conducted a high-resolution marine geophysical survey in the nearshore off southwestern Sri Lanka to determine the distribution, depositional environment and estimated volumes of granular sediment. The survey was the first step to identifying economic concentrations of heavy minerals. Geophysical equipment included a Simrad sidescan sonar system, an IKB Seistec subbottom profiler, and a Knudsen Engineering Ltd., 320M echo sounder. Sixty-eight grab samples provided selective ground truth of the interpreted seabed units. Analysis of the geophysical data quantified the thickness and volume of recoverable granular sediments. Eleven potential granular resource sites were identified. Estimated sediment volumes ranged from 2/spl times/10/sup 6/ m/sup 3/ to more than 120/spl times/10/sup 6/ m/sup 3/. Monazite concentrations as high as 1.1% were estimated based on gamma ray spectrometry analysis. No information exists on the subsurface concentration of heavy minerals. The 1997 marine geophysical results enabled development of a generalized model of the geomorphology and sediment distribution. Understanding the mechanisms of modern concentration of heavy mineral sands were used to develop hypotheses of emplacement during the geological evolution of the inner shelf. The model assists in identifying resource areas with the highest prospects for economic heavy mineral reserves.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"17 1","pages":"1611-1619 vol.3"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76977024","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 new Navy calibration standard transducer using 1-3 piezocomposite","authors":"K. Benjamin, S. Petrie","doi":"10.1109/OCEANS.2000.881783","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.881783","url":null,"abstract":"The design, fabrication, and acoustic calibration of a new 1-3 piezocomposite based U.S. Navy standard (USRD-F82) is presented. The F82 dual array/parametric mode projector may be used as a reciprocal linear transducer, or may be used to exploit the non-linear properties of the water to produce highly directional acoustic beams (4 to 2 deg.) at relatively low frequencies (5 to 60 kHz respectively). As a result of its wide bandwidth, a broad range of primary as well as secondary frequencies of operation are possible. In the linear mode of operation the transducer provides two separate arrays to be addressed topside for either transmit or receive applications. The two circular apertures are centered on the acoustic axis and have active diameters of 22.8 cm (9-inches) and 5.1 cm (2-inches). The smaller array aperture could be used to obtain less directional acoustic beams at relative high frequencies. Due to the absence of air filled pressure release components the transducer will operate over most ocean pressures and temperatures. A general description of the 1-3 piezocomposite based transducer configuration, and measured performance are presented.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"2 1","pages":"1299-1304 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88426741","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":"In situ calibration for beam attenuation coefficient determination at short pathlengths","authors":"R. Prien","doi":"10.1109/OCEANS.2000.881802","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.881802","url":null,"abstract":"A laboratory model of a short pathlength transmissometer with an in situ calibration facility was built to demonstrate the feasibility of high precision attenuation coefficient measurements at short pathlength even in clear waters. The high precision is enabled by the in situ calibration by variation of pathlength which is needed to overcome errors introduced by various sources such as window staining due to biofouling, multiple reflections at the glass-water interfaces and changes in refractive index of the medium. The laboratory model consists of a narrow bandwidth light source (LED) with a peak wavelength of 650 nm and beamforming optics, a moveable prism for retroreflection of the probe beam and receiving optics with a PIN-photodiode detector and transimpedance amplifier. With this setup a short term precision of the order of 10/sup -4/ m/sup -1/ was achieved at a constant pathlength of 54.7 mm. Drifts on longer terms, including staining of the instrument windows, can be compensated by the in situ calibration which showed a repeatability in the order of 10/sup -3/ m/sup -1/.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"1 1","pages":"1413-1419 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88597454","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":"Simulating an autonomous oceanographic sampling network: a multi-fidelity approach to simulating systems of systems","authors":"R. M. Turner, E. H. Turner","doi":"10.1109/OCEANS.2000.881372","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.881372","url":null,"abstract":"Many useful ocean engineering systems, such as autonomous oceanographic sampling networks (AOSNs) are actually systems of systems. Such systems are complex and require simulation during design and development. However, adequately simulating such systems is also difficult. The authors have developed an approach to multi-fidelity simulation that allows systems of systems to be simulated at several points along the spectrum from high-level, low-fidelity to low-level, high-fidelity simulation. They have implemented this approach a simulator for the CoDA (Cooperative Distributed AOSN control) project. Such an approach provides simulation support throughout the lifetime of the project, from design through proof-of-concept and beyond.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"13 1","pages":"905-911 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84011045","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 NOAA/UNH Joint Hydrographic Center and the UNH Center for Coastal and Ocean Mapping: an educational and research partnership of the Federal Government, the University of New Hampshire and ocean industry","authors":"A. Armstrong, L. Mayer","doi":"10.1109/OCEANS.2000.881334","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.881334","url":null,"abstract":"Ocean mapping technology is becoming an increasingly important tool in the full range of ocean-related enterprise. Moving well beyond its initial base in hydrographic surveying and nautical charting, ocean mapping has become a critical component of offshore oil exploration and development, submarine cable routing and installation, and geologic and essential fish habitat mapping. The technology of ocean mapping has blossomed rapidly in the past decade with the introduction of multibeam sonar, high-resolution side scan sonar, airborne lidar bathymeters, and laser line scan recorders. The next decade will likely see increased demand for ocean mapping data and continued demand for even more sophisticated ocean mapping technology. In response to this increased demand for ocean mapping data and the increasing complexity of ocean mapping technology, the National Oceanic and Atmospheric Administration (NOAA) and the University of New Hampshire (UNH) have established the complementary Joint Hydrographic Center (JHC) and Center for Coastal and Ocean Mapping (C-COM). The JHC is a NOAA/UNH partnership, and C-COM is a University organization with growing private sector participation. To provide NOAA and other program sponsors with the technology needed to meet their hydrographic and ocean mapping responsibilities, JHC and C-COM have developed a multidisciplinary and interdisciplinary program of research. The research program of the Centers has begun with principal themes encompassing ocean and electrical engineering, computer science, and earth science. Research topics will focus on sonar system capabilities and limitations; data processing, visualization, and presentation; seafloor characterization; and other new applications of seafloor mapping technology and data.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"67 1","pages":"705-709 vol.1"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82708739","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":"Riser protection nets-design considerations","authors":"H. McKenna","doi":"10.1109/OCEANS.2000.881800","DOIUrl":"https://doi.org/10.1109/OCEANS.2000.881800","url":null,"abstract":"Riser protection nets (RPN) for offshore oil production platforms present some very interesting design considerations. These nets are stretched between the columns of the platform to arrest encroaching supply vessels or other floating objects and to prevent them from striking the risers. Of particular interest is the application of relatively new types of synthetic fiber rope that is the main component of the net. This paper focuses on the role played in the design by these ropes but also includes other design considerations.","PeriodicalId":68534,"journal":{"name":"中国会展","volume":"27 4 1","pages":"1403-1406 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90940184","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}