2013 MTS/IEEE OCEANS - Bergen最新文献

{"title":"Geographical AODV protocol for multi-hop maritime communications","authors":"Youngchol Choi, Yong-Kon Lim","doi":"10.1109/OCEANS-BERGEN.2013.6608162","DOIUrl":"https://doi.org/10.1109/OCEANS-BERGEN.2013.6608162","url":null,"abstract":"Route request (RREQ) message is flooded to find a route in ad-hoc on-demand distance vector (AODV) routing protocol. This flooding of RREQ generates severe overheads in a maritime multi-hop ad-hoc network (MMANet) due to limited small bandwidth. In this paper, to improve the throughput of bandwidth-limited MMANet, we propose a geographical AODV (GAODV) protocol. The key feature of the GAODV is the selective broadcast of RREQ using position information. The routing overhead-traffic of the GAODV is smaller than that of AODV. This routing overhead-traffic reduction of the GAODV is more increased as the density of ship increases.","PeriodicalId":224246,"journal":{"name":"2013 MTS/IEEE OCEANS - Bergen","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124976548","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":"Comparison of modeling approaches to low-frequency noise propagation in the ocean","authors":"Alexios Korakas, J. Hovem","doi":"10.1109/OCEANS-BERGEN.2013.6608079","DOIUrl":"https://doi.org/10.1109/OCEANS-BERGEN.2013.6608079","url":null,"abstract":"In this study, the performance of a ray model for the prediction of long-range acoustic propagation in shallow-water scenarii, such as those encountered in coastal areas, is tested and discussed. Increased human activities in the marine environment over the recent years (seismic exploration, wind farming, shipping, etc.) has caused a significant general increase in ocean noise level, raising concerns over its impact on marine life and fisheries. Anthropogenic noise in the oceans covers a wide spectral range, including very low frequencies down to 10 Hz, and can propagate over large distances up to several tens of kilometers. Modeling the acoustic propagation to predict the noise impact in the marine environment thus becomes important for acoustic-system design in various applications and in compliance with the regulations regarding the uses of sound in the ocean. The study compares transmission-loss-versus-range curves calculated by a ray-tracing model (PlaneRay) with solutions by two wave-theoretic models particularly suited ti the shallow-water environment, namely a wavenumber integration (WI) model and a parabolic equation (PE)-based in a number of canonical test cases of increasing complexity. In particular, the WI model at hand allows for a combination of several fluid and elastic bottom layers in range-independent environments. On the other hand, the PE model at hand allows for comparisons in both range-independent and range-dependent environments with the bottom being described as all-fluid or all-elastic. The test cases are accordingly chosen to consist of a water layer lying over a fluid or elastic bottom half-space. Each case is analyzed and interpreted at several frequencies in the spectral range from 15 to 100 Hz. The comparison results show a good and promising agreement of the ray-tracing model with the PE and WI models. In particular, although based on the high-frequency approximation, the ray-tracing model appears to be an acceptable and efficient choice providing reliable predictions even at low frequencies and/or shallow-water environments.","PeriodicalId":224246,"journal":{"name":"2013 MTS/IEEE OCEANS - Bergen","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125015659","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 wind retrieval from GNSS delay-Doppler map using two-dimension least-squares fitting","authors":"Chen Li, Weimin Huang","doi":"10.1109/OCEANS-BERGEN.2013.6608019","DOIUrl":"https://doi.org/10.1109/OCEANS-BERGEN.2013.6608019","url":null,"abstract":"In this paper, a novel method is presented to retrieve sea surface wind speed and direction by fitting the two-dimensional simulated GNSS-R DDMs to measured data. The signal scattering model of Z-V and the sea surface roughness model of Cox and Munk are employed for the DDM simulation, and an 18-second incoherent correlation is performed on the measured signal to reduce the noise level. Meanwhile, a variable step-size iteration as well as a fitting threshold are used to reduce the computational cost and error rate of the fitting procedure, respectively. Unlike previous methods, all the DDM points with normalized power higher than the threshold are used in the least-square fitting. An optimal fitting threshold is also proposed. To validate the proposed method, the retrieving results based on a dataset from the UK-DMC satellite are compared with the in-situ measurements provided by the National Data Buoy Center, and good correlation is observed between the two.","PeriodicalId":224246,"journal":{"name":"2013 MTS/IEEE OCEANS - Bergen","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116762986","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":"Evolving offshore wind: A genetic algorithm-based support structure optimization framework for floating wind turbines","authors":"M. Hall, B. Buckham, C. Crawford","doi":"10.1109/OCEANS-BERGEN.2013.6608173","DOIUrl":"https://doi.org/10.1109/OCEANS-BERGEN.2013.6608173","url":null,"abstract":"This paper presents a genetic algorithm-based optimization framework for floating offshore wind turbine support structures. Using a nine-variable support structure parameterization, this framework spans a greater extent of the design space than preexisting optimization approaches in the literature. With a frequency-domain dynamics model that includes linearized hydrodynamic forces, linearized mooring forces, and linearized wind turbine effects, the framework provides a good treatment of the important physical considerations while still being computationally efficient. The genetic algorithm optimization approach provides a unique ability to visualize the design space. Application of the framework to a hypothetical scenario demonstrates the framework's effectiveness and identifies multiple local optima in the design space - some of conventional configurations and others more unusual. By optimizing to minimize both support structure cost and root-mean-square nacelle acceleration and plotting the design exploration in terms of these quantities, a Pareto front can be seen. Clear trends are visible in the designs as one moves along the front: designs with three outer cylinders are best below a cost of $6M, designs with six outer cylinders are best above a cost of $6M, and heave plate size increases with support structure cost. The complexity and unconventional configuration of the Pareto optimal designs may indicate a need for improvement in the framework's cost model.","PeriodicalId":224246,"journal":{"name":"2013 MTS/IEEE OCEANS - Bergen","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128041041","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":"An overview of underwater acoustics applied to observe fish behaviour at the Institute of Marine Research","authors":"N. Handegard","doi":"10.1109/OCEANS-BERGEN.2013.7028144","DOIUrl":"https://doi.org/10.1109/OCEANS-BERGEN.2013.7028144","url":null,"abstract":"Underwater acoustics have been used for decades to observe and enumerate fish and other marine taxa. As early as 1935 the technique was used to observe fish vertical distribution, and techniques to quantify fish abundance followed. Today, these techniques are widely used to inform fisheries management. However, fisheries acoustics are well suited to observe other properties than distribution and abundance. In this contribution I give an overview on recent advances at the Institute of Marine Research that enable us to quantify fish behavior using acoustics. The introduction of the split beam echo sounder was motivated by the need to locate single individual fish within the echo beam. By connecting the detections, tracks of fish could be established and tilt angles and swimming behavior could be inferred. This was important for resolving the tilt angle distribution for correct enumeration of the fish populations, but it is also an important tool for tracking individual fish in the open ocean. The technique has been used to track changes in individual fish behavior exposed to vessels in situ. Another tool to observe fish behavior is fisheries and multi beam sonars. Several sonar configurations exist in terms of frequency and beam configurations. Fisheries sonars operating at relatively low frequencies can be used to track the position and velocity to entire schools. Multi beam sonar can also be used to track the internal behavior in fish schools, and applications to collective internal dynamics of fish schools is presented.","PeriodicalId":224246,"journal":{"name":"2013 MTS/IEEE OCEANS - Bergen","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122892564","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":"State estimation of multiple autonomous underwater vehicles for wide area survey of seafloor","authors":"T. Matsuda, T. Maki, T. Sakamaki, T. Ura","doi":"10.1109/OCEANS-BERGEN.2013.6608192","DOIUrl":"https://doi.org/10.1109/OCEANS-BERGEN.2013.6608192","url":null,"abstract":"In this paper, we propose a state estimation method for navigation by multiple AUVs (Autonomous Underwater Vehicles) for wide area seafloor observation. The key idea is that moving AUVs estimate their states (horizontal position and heading angle) based on AUVs remaining stationary on the seafloor (landmark AUVs). By alternating the landmark role, each AUV navigates over wide area with small position drift. In our previous work, we demonstrated the case of two vehicles. We now expand this method to more than two vehicles. In the extended method, two AUVs alternate between the moving role and the landmark role, and the other AUVs constantly move and estimate only their own states based on the landmark AUV. To analyse the performance of the proposed method, navigation simulation was done. It was observed that the total time to cover the designated area became shorter as the number of the vehicles increased because every vehicle except a landmark vehicle can navigate simultaneously. Positioning errors were also estimated to be smaller than dead reckoning. Errors in position estimation were found to be about 1.1 m in horizontal position and about 0.6 degree in heading angle after navigating for over 120m × 500m by 4 vehicles. It was demonstrated that AUVs could cover the wide area faster and also achieve stable positioning by using the proposed method. Future works includes formulation of the error propagation in the multiple AUVs navigation.","PeriodicalId":224246,"journal":{"name":"2013 MTS/IEEE OCEANS - Bergen","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131630005","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":"Scalability analysis of underwater sensor networks","authors":"Gunnar Brataas, A. Lie, T. Reinen","doi":"10.1109/OCEANS-BERGEN.2013.6608067","DOIUrl":"https://doi.org/10.1109/OCEANS-BERGEN.2013.6608067","url":null,"abstract":"While underwater acoustic sensor networks (UWSN) are still considered to be in their development phase, professional users are starting to understand their future potential. For example, large areas encircling offshore oil installations need to be environmentally supervised. UWSNs consisting of a large number of sensor nodes can present a viable solution to this challenge. One way to build such networks is to divide the large area into multiple small clusters of sensor nodes, not very different from cellular mobile networks. Given a certain sensor node density, the question is then to determine the cluster sizes that provides optimum capacity or minimum number of high-cost sink nodes. This paper contains such a scalability analysis for underwater sensor networks, and presents a set of analytical expressions giving the relationship between underwater acoustic communication ranges and obtainable sink and sensor node densities in clustered underwater acoustic networks. Two propositions are presented that states a linear relation between cell capacities and MAC efficiencies, and how this capacity is reduced by inter-cell interference in a hexagonal cell topology. The propositions are validated using simulation experiments in WOSS/ns-miracle.","PeriodicalId":224246,"journal":{"name":"2013 MTS/IEEE OCEANS - Bergen","volume":"237 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127612273","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":"Single hydrophone passive source range and depth estimation in shallow water","authors":"Hannan Lohrasbipeydeh, T. Aaron Gulliver, A. Zielinski, Tom Dakin","doi":"10.1109/OCEANS-BERGEN.2013.6608042","DOIUrl":"https://doi.org/10.1109/OCEANS-BERGEN.2013.6608042","url":null,"abstract":"In this paper, the problem of underwater acoustic source localization using a single hydrophone is considered. The transmitted signal arrives at the hydrophone through the direct path and surface and bottom reflected paths. These multipath signals are used to define virtual hydrophones above the ocean surface and below the bottom for the purposes of source localization. An autocorrelation estimator is first used to estimate the delays of the reflected signals with respect to the direct path signal. Then a least squares estimator is applied to the time difference of arrival (TDOA) estimates of the three hydrophones to determine the source location. The performance of the proposed method is evaluated using the underwater data from the SWellEx-96 experiments which were conducted in San Diego, California.","PeriodicalId":224246,"journal":{"name":"2013 MTS/IEEE OCEANS - Bergen","volume":"200 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132533287","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":"Development of underwater robotic arm and leg for seabed robot, CRABSTER200","authors":"H. Shim, B. Jun, Hangoo Kang, S. Yoo, Gyeong-mok Lee, Pan-Mook Lee","doi":"10.1109/OCEANS-BERGEN.2013.6608167","DOIUrl":"https://doi.org/10.1109/OCEANS-BERGEN.2013.6608167","url":null,"abstract":"This paper presents the development of arm and leg of six-legged walking robot for precise seabed exploration and underwater works under coastal area with strong tidal current. For both seabed walking and precise underwater works, the seabed robot named CRABSTER200(CR200) uses six legs during walking and front two legs as manipulators during underwater work. To achieve the operation objective, the degree of freedom, dimensions, motion range, joint structure, and mass of the arm and leg are determined, and then suitable joint actuators and reduction gears are selected through a simple force analysis. In addition, a communication method, actuator controllers, and sensors are selected. The detailed mechanical design for 200m class pressure-resistance and watertight is performed, and the arms and legs are built by fabricating the mechanical parts and assembling them. Finally, in order to verify the performance of the arm and leg, the watertight test with 25bar pressure-resistance and joints operating test by using a posture control of CR200 are performed. This paper describes the whole design and implementation process of the underwater robotic arm and leg of the seabed robot CR200.","PeriodicalId":224246,"journal":{"name":"2013 MTS/IEEE OCEANS - Bergen","volume":"166 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132663438","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":"Improving the measurements of high frequency radar: Reduced averaging times and bistatics","authors":"H. Roarty, J. Kerfoot, J. Kohut, S. Glenn, C. Whelan, M. Hubbard","doi":"10.1109/OCEANS-BERGEN.2013.6608082","DOIUrl":"https://doi.org/10.1109/OCEANS-BERGEN.2013.6608082","url":null,"abstract":"High Frequency radar has been operational with the US Coast Guard since May 2009. The long-range SeaSonde is a key component of the national HF radar network. Default SeaSonde processing on long-range systems only captures 92% of the M2 tidal current velocity and hence 85% of the tidal energy due to a 180-minute averaging time. Reducing this averaging time would help improve the surface current measurements of the SeaSonde system. A study was undertaken to analyze the radial processing of the long-range SeaSonde. Radial current files were generated using a sixty-minute radial averaging and compared with the default one hundred and eighty minute average. This was performed at five stations in the northern section of the Mid Atlantic Regional Association Coastal Ocean Observing System (MARACOOS) for a two-week period. This study has implications for the thirty-five long-range radars operating in the United States and the approximately eighty-six long-range radars operating around the globe. The hope being that the shorter averaging time will lead to increased accuracy of the measured surface currents. This in turn will lead to more effective search and rescue cases for the US Coast Guard. Another study was conducted to measure the impact that bistatic radar has on the measurements of surface currents. A 13 MHz radar network was used to test to see if elliptical current measurements would decrease the uncertainty of a total surface current measurement. A three-week record of hourly radial and elliptical measurements were used and combined in several configurations to test the impact of the elliptical currents. Initial findings show that the elliptical current measurements decreased the uncertainty of the total vector calculation and reduced gaps due to missing radial data.","PeriodicalId":224246,"journal":{"name":"2013 MTS/IEEE OCEANS - Bergen","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133323825","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}