OCEANS 2007最新文献

{"title":"A Precise Acoustic Distance Measuring System for Tectonic Plate Motion","authors":"L. Zhou, A. Zielinski, P. Kraeutner","doi":"10.1109/OCEANS.2007.4449161","DOIUrl":"https://doi.org/10.1109/OCEANS.2007.4449161","url":null,"abstract":"This paper proposes a new distance measuring system to monitor tectonic plate motions. The method is based on estimation of phase shift between two acoustic signals. The measurement error of plate displacement is determined by the phase estimation error. Phase estimation is performed with a conventional quadrature phase estimator in this paper. Simulation results show that under ideal conditions, the root-mean-square (RMS) error of the displacement estimation is within 1 millimetre when the signal-to-noise ratio (SNR) equals OdB. This error can be further reduced if we use a longer transmission pulse. Measurement errors caused by environmental factors such as ocean currents are also addressed. Reciprocal transmission is suggested to reduce this effect.","PeriodicalId":214543,"journal":{"name":"OCEANS 2007","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114298707","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 Coastal Ocean Prediction System for Tampa Bay, Florida","authors":"M. Luther, S. Meyers, S. Gilbert, V. Subramanian, Michelle McIntyre, Monica Wilson, Heather Havens, Amanda J. Linville","doi":"10.1109/OCEANS.2007.4449385","DOIUrl":"https://doi.org/10.1109/OCEANS.2007.4449385","url":null,"abstract":"The USF College of Marine Science has developed a Coastal Ocean Prediction System for Tampa Bay based on an integrated observing system and circulation model as a sub-regional component of the US Integrated Ocean Observing System. The model system ingests real-time observations of the physical forcing functions for Tampa Bay to produce three-dimensional fields of circulation, temperature, salinity, and water level. The hydrodynamic model, based on the ECOM-3D code, is fully operational in either a nowcast-forecast mode or a hindcast mode and is described on our web site (http://ompl.marine.usf.edu/TBmodel). Water level, temperature, salinity, surface heat and moisture fluxes, and winds come from the Tampa Bay Physical Oceanographic Real-Time System (TB-PORTS; http://ompl.marine.usf.edu/ports/ or http://tidesandcurrents.noaa.gov/tbports/tbports. shtml?port=tb) augmented with observations from the USF Coastal Ocean Monitoring and Prediction System (COMPS; http://comps.marine.usf.edu/). Daily river discharge is obtained from the USGS National Water Information System. Precipitation is derived from several gauges operated by the Southwest Florida Water Management District, USGS, and NOAA. The raw observational data undergoes an automated QA/QC procedure before being input into the model. A water quality module has been developed that produces fields of chlorophyll, nutrients, and dissolved oxygen from time- varying estimates of nutrient and fresh water loading. A wave module provides directional wave spectra and bottom stresses based on the SWAN code. The integrated observing and modeling system provides a decision support tool that is used to enhance security, safety, and efficiency of maritime transportation, to guide search and rescue efforts, and to evaluate the bay ecosystem response to environmental stressors. Such stressors include severe storms, seasonal and interannual changes in fresh water input, as well as human impacts, such as hazardous material spills, river withdrawals, nutrient loading, changing land use patterns, and alterations in bay bathymetry. In addition to its routine use by the Tampa Bay Pilots and the US Coast Guard, the Coastal Ocean Prediction System has been used to support management decisions in several environmental issues affecting the bay. For example, the model has been used to investigate the effects of concentrate discharge from a seawater desalination facility recently built on Tampa Bay for the regional water supply authority; to simulate the trajectory of wastewater discharges and hazardous material spills for the Florida Department of Environmental Protection; to predict trajectories of raw sewage spills into the bay for the Pinellas County Health Department; to investigate transport and fate of human pathogens in the bay, and to evaluate changes in salinity and estuarine residence time due to natural variability and to anthropogenic alterations in fresh water input and bathymetry of the bay for the Southwest ","PeriodicalId":214543,"journal":{"name":"OCEANS 2007","volume":"46 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115787077","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":"Underwater Protection System","authors":"A. Lovik, A.R. Bakken, J. Dybedal, T. Knudsen, J. Kjoll","doi":"10.1109/OCEANS.2007.4449131","DOIUrl":"https://doi.org/10.1109/OCEANS.2007.4449131","url":null,"abstract":"With the emerging asymmetrical threat to harbours, vessels and areas of special interest the need for both fixed and portable protection systems are imminent. This paper describes a system approach to the problem of protecting vital assets from divers and swimmers all the way from the initial detection through to the choice of reaction including the use of UUV and non-lethal acoustic deterrent units. A vital part of the system described is a novel new sonar system using wideband technology for increased sonar performance in shallow and highly reverberant environments. Further the frequency range has been lowered compared to the standard diver detection sonar of to-day, to give a potential for improved detection ranges and thereby provide more time for carrying out an appropriate reaction. The wideband technology may also lead to a new set of classification tools. The paper outlines the system and specifically discusses tests done in harbours and enclosed environments with the sonar system against divers and UUVs. Detection and classification issues are discussed and examples of obtained system performances are given.","PeriodicalId":214543,"journal":{"name":"OCEANS 2007","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115803332","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":"Broadband acoustic transmission measurements in surface ship wakes","authors":"Steve Stanic, E. Kennedy, Bob Brown, D. Malley, Ralph Goodman, Jerauld Caruthers","doi":"10.1109/oceans.2007.4449232","DOIUrl":"https://doi.org/10.1109/oceans.2007.4449232","url":null,"abstract":"This paper describes as series of experiments designed to obtain estimates of the spatial bubble characteristics within a surface ship wake. By using measurements of the across the wake time dependent transmission loss at a single depth, estimates of the excess absorption due to the bubbles in the wake were obtained as a function of wake age and frequency. Using the theory of absorption in a bubbly medium, estimates of the bubble number densities as function of wake age, and acoustic transmission frequency were then obtained. In the future, the authors will use the data from the towed array to obtain estimates of the signal correlation functions.","PeriodicalId":214543,"journal":{"name":"OCEANS 2007","volume":"747 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122967137","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":"Monitoring and Controlling System Performance in the Pioneer Buoy","authors":"D. Murray, T. Consi","doi":"10.1109/OCEANS.2007.4449237","DOIUrl":"https://doi.org/10.1109/OCEANS.2007.4449237","url":null,"abstract":"The Pioneer buoy is part of an aquatic observatory, known as GLUCOS (Great Lakes Urban Coastal Observing System), being developed by the University of Wisconsin-Milwaukee Great Lakes WATER Institute. The buoy can function as a rapid deployment system for measuring transient phenomena, or as a controller and wireless communication hub for large specialized instruments, such as water samplers or sediment traps. It is easily reconfigurable in order to satisfy the changing requirements of different scientific experiments. Changes in configuration are made possible by implementation of a modular design, with components that can be added or removed without affecting the overall functionality of the system. All components are designed and operated so that power consumption is minimized, due to the limited space for an onboard power supply and the lack of photovoltaic panels. In addition to the scientific data being collected by the observatory, the remote and potentially harsh deployment environment of each buoy system necessitates the collection of as much device performance data as is practical. This data can be used to correct for sensor errors, assess buoy performance, and to provide information for future, improved, buoy designs. This paper discusses the hardware and software design as well as test results of the Pioneer Buoy self-monitoring and control system.","PeriodicalId":214543,"journal":{"name":"OCEANS 2007","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123283428","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":"Cramer-Rao Bound for Bearing Estimation with Bias Correction","authors":"Wen Xu","doi":"10.1109/OCEANS.2007.4449399","DOIUrl":"https://doi.org/10.1109/OCEANS.2007.4449399","url":null,"abstract":"The Cramer-Rao lower bound (CRB) has been extensively used in parameter estimation performance analysis. It can be achieved by a maximum likelihood estimator (MLE) for sufficiently high SNR; however below certain SNR the MLE mean-square error departs significantly from the CRB, displaying a threshold behavior. This departure is partially attributed to the fact that an MLE with nonlinear parameter dependence is biased at low SNR while a local performance bound such as the CRB is limited to unbiased estimates. Indeed the information theory inequality, from which the CRB can be derived, does include some bias-related terms, which are ignored in the commonly-referred form of the CRB (i.e., inverse of the Fisher information) due to evaluation difficulty. Using a first- order approximation of the MLE bias, this paper presents a complete CRB including both the bias contribution and the Fisher information, and applies it to array-based bearing estimation analysis. Evaluation examples demonstrate that the revised CRB displays some threshold behavior; however it is still far apart from the MLE simulations. The results suggest that 1) a more accurate bias estimation must be exploited to make the approach practically meaningful; and 2) it may make more sense to combine the bias contribution with a large error bound such as the Barankin bound so that both mainlobe and sidelobe ambiguities are taken into account.","PeriodicalId":214543,"journal":{"name":"OCEANS 2007","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123530774","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":"Nonhydrostatic Hindcasts of High Amplitude Internal Waves in the Mid-Atlantic Bight","authors":"P. Gallacher, M. Schaferkotter, W. Avera","doi":"10.1109/OCEANS.2007.4449368","DOIUrl":"https://doi.org/10.1109/OCEANS.2007.4449368","url":null,"abstract":"From late July to early September 2006 an intense field program, Shallow Water 2006 (SW06), was conducted in the Mid-Atlantic Bight (MAB) off of the New Jersey coast. The goal of the program is to the determine the environmental processes that affect shallow water acoustic propagation and scattering and to understand the dynamics of the generation and evolution of those processes. A phenomena that dominates much of the hydrodynamics in the coastal ocean are the internal waves. The waves interact with each other, with the topography and with the ambient currents and stratification to form a complex field of baroclinic internal waves of varying frequencies and wavelengths. Many of these waves are nonlinear and have very high amplitudes (exceeding 50 m) hence large energy. The generation, interactions and transformations of these waves is studied with a very high resolution, nonhydrostatic (NRL-MIT) model system of the ocean hydrodynamics. This model is imbedded in a nested hydrodynamic nowcast/forecast system comprised of the global Navy Coastal Ocean Model (NCOM) and a series of higher resolution NCOM domains.","PeriodicalId":214543,"journal":{"name":"OCEANS 2007","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123679656","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":"Vocalization based Individual Classification of Humpback Whales using Support Vector Machine","authors":"Suleman Mazhar, T. Ura, R. Bahl","doi":"10.1109/OCEANS.2007.4449356","DOIUrl":"https://doi.org/10.1109/OCEANS.2007.4449356","url":null,"abstract":"Visual surveys and DNA analysis hold primary importance in marine mammal observation. Especially, recognition of whales and their population density estimation rely heavily on these costly and tedious methods. Acoustic survey of vocalizing cetaceans, in contrast, is emerging as a promising technique for efficient, automatic, non-invasive and convenient observation and analysis of such vocally active organisms. However, it is, yet, too premature to replace the conventional methods altogether. In this paper, we have presented our results on recognition of individual humpback whales based on their vocalization data. Cepstral coefficients from song units extracted from audio records of seven humpback whales, re-sampled at 8KHz, were subjected to cepstral analysis. The extracted coefficients were used to develop multi-class support vector machine (SVM) classifier model. The test phase results indicated classification accuracy as high as 99% as compared to earlier best results of 88%, achieved by Gaussian mixture model (GMM) trained on cepstral coefficients. Furthermore, this improvement was attained with a highly reduced training dataset size. It was also verified that the song duration of approximately 128 seconds was sufficient for reliable identification in test phase for given dataset.","PeriodicalId":214543,"journal":{"name":"OCEANS 2007","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121407528","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":"Laser Raman Spectroscopic Analyses of Dissolved Gases","authors":"S. N. White","doi":"10.1109/OCEANS.2007.4449273","DOIUrl":"https://doi.org/10.1109/OCEANS.2007.4449273","url":null,"abstract":"Laser Raman spectroscopy is an optical technique which is capable of in situ molecular identification of solids, liquids and gases, and is well suited to extreme environments. It is a type of vibrational spectroscopy which is non-invasive and does not require reagents or consumables. A laser excites a target, and the spectrum of the energy-shifted, back-scattered radiation serves as a \"fingerprint\" - providing compositional and structural information. Raman scattering is a weak effect - only 1 in 108 photons is Raman scattered - but it benefits in the deep ocean from the lack of ambient light. The development of a sea-going Raman system capable of deployment on an ocean observatory will allow in situ analyses of dissolved gases in vent fluids at hydrothermal vent and other seafloor seep sites. Gases of interest at hydrothermal and cold seep sites include carbon dioxide (CO2), methane (CH4) and higher hydrocarbons, and hydrogen sulfide (H2S). These gases are all Raman active and have distinct Raman signatures. For example, CO2 is characterized by a Fermi diad at ~1285 & ~1388 Deltacm-1 . However, the aqueous band positions are broadened and shifted from the gas-phase band positions. In addition to identifying gases by band positions, concentrations of dissolved gases can be inferred by the relative height of their Raman bands. Extracting this type of quantitative information from Raman spectra requires the use of a ratio technique as described by Wopenka and Pasteris [1987]. In this work the gas bands are compared to the water stretching band (~3435 Deltacm-1 ). Although the position and intensity of some of the water bands are affected by temperature, the 3435 band height is relatively stable.","PeriodicalId":214543,"journal":{"name":"OCEANS 2007","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122545372","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 VENUS Cabled Observatory: Engineering Meets Science on the Seafloor","authors":"R. Dewey, A. Round, P. Macoun, J. Vervynck, V. Tunnicliffe","doi":"10.1109/OCEANS.2007.4449171","DOIUrl":"https://doi.org/10.1109/OCEANS.2007.4449171","url":null,"abstract":"The VENUS cabled ocean observatory is one of the first in the next generation of ocean observing platforms. It is an integration of marine telecommunication and sub-sea technologies with oceanographic instrument systems, accessible over the Internet. Commands originate at the network operations centre and are piped over a virtual private network (VPN) through a shore station and down a marine fibre optic cable to the sub-sea components consisting of central nodes, instrument interface modules, and instrument systems. Data from the instrument sensors flows through the infrastructure and is briefly buffered at the shore station before being transmitted over the Internet to the data management and archive system (DMAS) at the University of Victoria. Here the information is sorted and stored for publication on the project web site and retrieval by observatory users. The observatory consists of 2 independent arrays located in the coastal waters of southern British Columbia. The first is in Saanich Inlet with a node at the 96 m depth near the entrance to Patricia Bay. The second array is in the Strait of Georgia, with two nodes southwest of the main mouth of the Fraser River, including a deep node at 300 m and a shallow node at 170 m. Among the challenges has been the engineering design and installation of a complex sub-sea facility that is both flexible and robust, while meeting the needs of the scientific research community. The main components of the VENUS observatory, the initial suite of instrument systems, and the preliminary data retrieval methods are presented. For the latest data and system status, visit the VENUS website at: http://www.venus.uvic.ca/.","PeriodicalId":214543,"journal":{"name":"OCEANS 2007","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123870529","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}