2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO)最新文献

{"title":"Flow Noise Calculation and Suppression for Sonobuoy","authors":"Chunlong Huang, Kunde Yang, Yuanliang Ma, Quan Sun","doi":"10.1109/OCEANSKOBE.2018.8559090","DOIUrl":"https://doi.org/10.1109/OCEANSKOBE.2018.8559090","url":null,"abstract":"The sea waves can make sonobuoy vibrate in the vertical direction. The vibration can create flow noise which will affect the work performance of the sonobuoy. It can be suppressed by adding flexible cable to the structure of the sonobuoy. In this paper, we first establish a theoretical model used in calculating the flow noise of sonobuoy to analyze the corresponding relationship between the flow noise and the vibration velocity. Then we establish a forced vibration model of the sonobuoy to analyze the effect of flexible cable on suppressing flow noise caused by vibration of the sonobuoy. According to the simulation results calculated by the flow noise theoretical calculation model, we find that the spectrum level of the flow noise increases with the increase of the flow velocity. According to the simulation result calculated by the sonobuoy vibration model, we find that choosing an appropriate elastic coefficient for the flexible cable can effectively suppress the vibration of the sonobuoy caused by the sea waves. As a consequence, the flow noise of the sonobuoy can be reduced effectively.","PeriodicalId":441405,"journal":{"name":"2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130868649","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 AUV Mounted Vector-Sensor for Seismic Surveying","authors":"P. Felisberto, P. Santos, F. Zabel, S. Jesus, L. Sebastião, A. Pascoal","doi":"10.1109/OCEANSKOBE.2018.8559205","DOIUrl":"https://doi.org/10.1109/OCEANSKOBE.2018.8559205","url":null,"abstract":"The innovative usage of robotic vehicles for seismic surveying where, in sharp contrast to classical solutions, acoustic sources and streamers are carried by Autonomous Surface and Underwater Vehicles (ASVs & AUVs), respectively poses significant scientific and technical challenges. Among these, is the requirement of reducing the streamers length to improve the maneuverability and endurance of the towing vehicles without compromising the resolution of bottom images. A possible approach to tackle this challenge is to use vector sensors (VS) that are both compact and have high spatial discrimination performance. Such a sensing device - known as the Dual Accelerometer Vector Sensor (DAVS) - was designed, developed and tested in the framework of the WiMUST project. This work describes the experimental setup adopted and analyzes the data acquired during engineering trials carried out at the Lisbon Oceanarium marina, in Portugal, with a sparker mounted on an ASV and a DAVS mounted on a companion AUV. The Oceanarium marina is a very shallow site where the direct, surface and bottom reflected arrivals overlap in time. The results show that DAVS data can be used to attenuate noise and undesired surface reflections, and separate bottom and surface arrivals. Therefore, they suggest that a few VS can achieve a performance similar to that of longer hydrophone streamers and be advantageous in challenging survey areas where the traditional seismic setup can not be adopted.","PeriodicalId":441405,"journal":{"name":"2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO)","volume":"37 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114108735","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":"BioFREE: An International Study of Biofouling Impacts on the Marine Renewable Energy Industry","authors":"A. Want, J. Porter","doi":"10.1109/OCEANSKOBE.2018.8559322","DOIUrl":"https://doi.org/10.1109/OCEANSKOBE.2018.8559322","url":null,"abstract":"The success of the marine renewable energy (MRE) industry is dependent upon maximising energy capture and minimising down-time. Device performance is negatively impacted by the growth of fouling organisms, leading to reduced efficiency and reliability; anti-fouling strategies are costly and time consuming. Biofouling also reduces accuracy of data buoys and sensors used to assess the hydrodynamic resource and device performance. While biofouling has been a recognised problem for centuries, deployment of MRE devices creates several unique issues. Additional concerns exist over the role that MRE infrastructure may play as ‘stepping-stones’ promoting the spread of non-native and invasive species. A paucity of published studies exists concerning biofouling in this sector. With a general trend towards stricter environmental controls, it is essential that the MRE industry demonstrate commitments that minimise disturbance and promote positive impacts. Given small margins for MRE, there are potentially substantive benefits from tackling biofouling in terms of increased investor confidence. The BioFREE project (a collaboration between Heriot-Watt University and the European Marine Energy Centre (EMEC) in the UK) is addressing these issues by detailed characterisation of the biofouling communities from multiple habitats used by the MRE sector, and monitoring benthic impacts following deployment and decommissioning. BioFREE is developing a workable Standard Monitoring System designed to facilitate data collection using practical and effective methods. Frames are populated with settlement panels, data loggers, and components comprised of materials of greatest concern to MRE developers. Components of this system can be treated with anti-fouling coatings. Frames are being deployed in a variety of habitats at additional test centres and research institutes located in Japan, Chile, France, and the USA; organisms are recorded quarterly to identify the major foulants, determine the rate of settlement and growth, and study successional changes. These studies indicate strong species-specific seasonal settlement patterns. Fouling communities vary between deployment habitats depending on factors such as hydrodynamic conditions, water depth, and substrate type. These findings will allow recommendations for test centres and developers to minimise the impacts of fouling, chiefly through selective scheduling of deployments and maintenance, in different habitats, to times when the settlement of fouling organisms will be minimal or their removal will be least costly. In addition, BioFREE has created training materials to help inform the MRE industry of ways to better capture biofouling information when conducting operations at sea. Practical suggestions are informed by recent maintenance and decommissioning operations conducted on MRE infrastructure. These studies have identified structural areas and materials of particular concern from the impacts of biofouling. The lead ro","PeriodicalId":441405,"journal":{"name":"2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125192649","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":"Autonomous Optical Survey Based on Unsupervised Segmentation of Acoustic Backscatter","authors":"Øystein Sture, T. Fossum, M. Ludvigsen, M. Wiig","doi":"10.1109/OCEANSKOBE.2018.8559211","DOIUrl":"https://doi.org/10.1109/OCEANSKOBE.2018.8559211","url":null,"abstract":"The application of acoustics to study the seabed have for decades provided industry and science with valuable information, and is still excels in terms of spatial coverage and detail. An acoustic response from the seabed not only contains information about the range, through the two way travel time, but also the acoustic reflectivity of the substrate from the strength of the backscatter response. As the signal strength differs between substrate types, this information can be used to detect and classify different seabed types. However, there are ambiguities in the acoustic signatures and the reliance on ground truth samples, for succeeding in this identification, is a limiting factor. In this paper we present a way to mitigate this problem using Hidden Markov Random Fields (HMRF) to perform unsupervised segmentation of the backscatter response for the purpose of determining different seabed types. The outcome of this analysis is directly used to plan and conduct an autonomous near-seabed camera survey to verify the classification results, whilst complementing the acoustical data-set. The method is tested in a full-scale experiment and performed in-situ onboard a Kongsberg Hugin 1000 autonomous underwater vehicle (AUV).","PeriodicalId":441405,"journal":{"name":"2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121764927","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 Model for the Two-Dimensional Acoustic Cloak","authors":"Wei Li, Mignsheng Wang","doi":"10.1109/OCEANSKOBE.2018.8559241","DOIUrl":"https://doi.org/10.1109/OCEANSKOBE.2018.8559241","url":null,"abstract":"A new formula is proposed for a two-dimension anisotropic acoustic cloak based on the sound speed matching and sound boundary impendence matching. In this model, a crucial parameter is involved in the expression for the acoustic cloak material. Based on the effective medium approximation theory, the acoustic cloak is reconstructed with multilayered structure composed of homogeneous isotropic materials. The proposal formula exhibits different exponent variables to investigate the invisible effects of the acoustic cloak The real part distributions of the pressure field demonstrate that the incident wave could pass through the acoustic cloak with an unchanged wavefront direction during an appropriate region for the exponent variable. The proposed design of the acoustic cloak could be applied as guidance for the multilayered acoustic cloak composed by existing material in reality.","PeriodicalId":441405,"journal":{"name":"2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115205250","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":"Fast and Ultra-Wide Area Bathymetric Survey System Without Support Vessel","authors":"Takeshi Ohki, T. Nakatani, Yuya Nishida, B. Thornton","doi":"10.1109/OCEANSKOBE.2018.8559056","DOIUrl":"https://doi.org/10.1109/OCEANSKOBE.2018.8559056","url":null,"abstract":"Autonomous underwater vehicle (AUV) operations require manned support vessel for communication, navigation, deployment, and recovery. Because the number of the support vessel is limited, the strong tie between AUV and support vessel prevents to operate many AUVs simultaneously. Since this problem has been shared in oceanic markets, we propose a compact and mobile package of multi-robot system to realize fast and ultra-wide area bathymetric survey without support vessel. The proposed system consists of several numbers of AUVs, single autonomous surface vehicle (ASV), and ground mission control. The proposed system includes an unmanned deploy and recovery system, which enables towing, deploying and recovering multiple AUVs by an ASV without manned support vessel. The three AUVs can equip different payloads and basically follow the order of forming a convoy from the ASV which is also supervised by operators at a remote ground base station. Satellites communications are used between the ground base station and the ASV, and acoustic communications are used between the ASV and the ASVs. The proposed system has been developed and implemented. Several sea-trials had been conducted to confirm the validity of the proposed system. In this paper, we introduce the overall design concept of the proposed system and the recent activities.","PeriodicalId":441405,"journal":{"name":"2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128675193","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":"On Prediction Method of Optimized Control Parameters for an Array of Point Absorber Type Wave Energy Converters in Waves","authors":"M. Murai, Qiao Li, J. Funada, Hasuki Shigetome","doi":"10.1109/OCEANSKOBE.2018.8558847","DOIUrl":"https://doi.org/10.1109/OCEANSKOBE.2018.8558847","url":null,"abstract":"Using marine renewable energy can contribute providing the energy instead of using fossil fuel. There are some types of marine renewable energy. Wave energy is one of these and no one doubts its vast potential once they glance the sea. The object of this paper is an array of Point Absorber Wave Energy Converters (PA-WECs). In the array, hydrodynamic interactions among the array will be increase. When we consider the maximization of generated electric power of the array, the suitable choice of the control force of the generator is the key. In the past research, as for the detection of the suitable control force of the single PA-WEC it has been shown the analytical solution within linear system. In this paper, we show the analytical solution of the control force parameter for maximizing the generated electric power of the array taking the hydrodynamic interaction among the array both in diffraction and radiation problem into account. Then we carried out the numerical examination and discussed the validation of the proposed formulation and the good arrangement of an array in waves based on the proposed formulation.","PeriodicalId":441405,"journal":{"name":"2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117310942","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":"Viterbi Detection of PSK Signals in Markov Impulsive Noise","authors":"Ahmed Mahmood, M. Chitre","doi":"10.1109/OCEANSKOBE.2018.8558810","DOIUrl":"https://doi.org/10.1109/OCEANSKOBE.2018.8558810","url":null,"abstract":"The ambient soundscape in warm shallow waters is dominated by snapping shrimp noise at frequencies greater than 2 kHz. The noise process is impulsive and exhibits memory. Within the human audible range, this manifests as a persistent background crackle, akin to the popping of corn. Unless catered for, underwater acoustic communication systems are vulnerable to large drops in error performance in such waters. With the advent of new effective statistical models, namely the $alpha$-sub-Gaussian noise model with memory order $m(alpha mathbf{SGN}(m))$, it is now possible to mitigate snapping shrimp noise by exploiting the latter's temporal amplitude statistics. In our work, we accomplish this by deriving the passband Viterbi algorithm (VA) for a single-carrier scheme in $alpha mathbf{SGN}(m)$. The results are compared to the symbol-by-symbol maximum-likelihood (ML) detector and conventional L2-norm detection in scenarios representative of severe snapping shrimp noise. As the VA algorithm is optimal in $alpha mathbf{SGN}(m)$, it is of much interest to know how it fairs in snapping shrimp noise. This is investigated in our work.","PeriodicalId":441405,"journal":{"name":"2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124475370","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":"Online Informative Path Planning Using Sparse Gaussian Processes","authors":"Rajat Mishra, M. Chitre, Sanjay Swarup","doi":"10.1109/OCEANSKOBE.2018.8559183","DOIUrl":"https://doi.org/10.1109/OCEANSKOBE.2018.8559183","url":null,"abstract":"Estimating the environmental fields for large survey areas is a difficult task, primarily because of the field's spatio-temporal nature. A good approach in performing this task is to do adaptive sampling using robots. In such a scenario, robots have limited time to collect data before the field varies significantly. In this paper, we suggest an algorithm, AdaPP, to perform this task of data collection within a constraint on sampling time and provide an approximation of the environmental field. We test our performance against conventional sampling paths and show that we are able to obtain a good approximation of the field within the stipulated time.","PeriodicalId":441405,"journal":{"name":"2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132487890","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":"Path Planning of Multi-UAS Communication Relay by Decentralized MPC","authors":"Fabio Augusto de Alcantara Andrade, Christopher Dahlin Rodin, A. Hovenburg, T. Johansen, R. Storvold","doi":"10.1109/OCEANSKOBE.2018.8559333","DOIUrl":"https://doi.org/10.1109/OCEANSKOBE.2018.8559333","url":null,"abstract":"When using Autonomous Surface Vehicles (ASV) in marine operations, long distances and/or low power transmissions may severely limit the communication between the ASV and the ground station. One solution to overcome this obstacle is to use a group of small Unmanned Aerial Systems (UAS) to act as relay nodes, in order to provide a user-defined minimum communication capability. To achieve this, we propose a decentralized cooperative multi-agent system using fixed-wing UAS with nonlinear model predictive control, which aims to guarantee a desired signal strength between the ASV and the ground station. The novelty of the presented research resides in the inclusion of the aircraft performance model and the effects of wind, together with the inclusion of the directivity of the antennas. Experimental results of the proposed method are obtained through simulations.","PeriodicalId":441405,"journal":{"name":"2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114720629","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}