Pub Date : 2014-04-07DOI: 10.1109/OCEANS-TAIPEI.2014.6964573
Yuehai Zhou, Kun Zeng, F. Tong, Yougan Chen
MIMO systems is capable of achieving two to three spatially parallel communication channels in very shallow water to improve communication performance as well as capacity. For MIMO communications, simultaneous presence of multipath and co-channel interference poses substantial difficulties for the design of receiver. While the classic space-time multi-channel DFE receiver consisting of multiple DFE equalizers is limited by high computational complexity when multipath time delay is large, the low complexity time reversal receiver needs a large number of receivers (>10) to achieve satisfactory performance. This paper presents the design of a selective time reversal underwater acoustic MIMO communication receiver to accommodate the small receiver number of space-time DFE and the multipath focusing capability of time reversal by coupling the time reversal with multi-channel DFE. Sea trial experiments are carried out to demonstrate the superior performance of the proposed method.
{"title":"Selective time reversal receiver for shallow water acoustic MIMO communications","authors":"Yuehai Zhou, Kun Zeng, F. Tong, Yougan Chen","doi":"10.1109/OCEANS-TAIPEI.2014.6964573","DOIUrl":"https://doi.org/10.1109/OCEANS-TAIPEI.2014.6964573","url":null,"abstract":"MIMO systems is capable of achieving two to three spatially parallel communication channels in very shallow water to improve communication performance as well as capacity. For MIMO communications, simultaneous presence of multipath and co-channel interference poses substantial difficulties for the design of receiver. While the classic space-time multi-channel DFE receiver consisting of multiple DFE equalizers is limited by high computational complexity when multipath time delay is large, the low complexity time reversal receiver needs a large number of receivers (>10) to achieve satisfactory performance. This paper presents the design of a selective time reversal underwater acoustic MIMO communication receiver to accommodate the small receiver number of space-time DFE and the multipath focusing capability of time reversal by coupling the time reversal with multi-channel DFE. Sea trial experiments are carried out to demonstrate the superior performance of the proposed method.","PeriodicalId":114739,"journal":{"name":"OCEANS 2014 - TAIPEI","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129874378","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}
Pub Date : 2014-04-07DOI: 10.1109/OCEANS-TAIPEI.2014.6964436
Y. Kaneda, E. Araki, H. Matsumoto, Takeshi Nakamura, S. Kamiya, K. Ariyoshi, T. Hori, M. Takahashi, T. Baba, M. Nakano, Jin-Kyu Choi, S. Nishida
The Nankai trough is one of the largest and hazardous seismogenic zones in the world. Around the Nankai Trough, there are 3 mega thrust earthquake seismogenic zones such as the Tokai, Tonankai and Nakai seismogenic zones. Especially, the estimation of seismic linkage between the Tonankai and Nankai seismogenic zone is very important and indispensable for the reduction of earthquake and tsunami damages. Actually, the Tonankai and Nankai earthquake occurred in 1944/ 1946, 1854 as the seismic linkage events. Therefore, for understandings of early warning and prediction of erathquakes and tsunamis, the ocean floor network equipped with multi kinds of sensors such as seismometers and pressure gauges are very important and significant tool to monitor the broad band phenomena in the Nankai seismogenic zones. In the Tonankai seismogenic zone, we constructed DONET (Dense Ocean floor Network for Earthquakes and Tsunamis) with 20 observatories for early warning and improvement of prediction reliability. Multi kinds of sensors such as an accelerometer, a broad band seismometer, a precise pressure gauge, a differential pressure gauge and a precise thermometer are equipped in each observatory. Furthermore, the long term borehole observatory system with the seismometer, strainmeter, tiltmeter etc. is already installed in the drilled hole by IOPD NanTroSEIZE project, finally, this system will connect to DONET for the 3 dimensional real time monitoring. Now, we are already developing DONET2 with 31 observatories around the Nankai seismogenic zone and will complete deployments within 3 years. DONET2 system is more powerful rather than DONET system to monitor the large seismogenic zone areas. Especially, these offshore real time data will be applied to estimate of tsunami scales. We have to learn the lesson from tsunami damages of East Japan Earthquake 2011, Sumatra Earthquake 2004 etc. So, we are developing the advanced tsunami early estimation system using not only real time monitoring but also advanced simulation.
{"title":"Advanced technology and application of the ocean floor observatory around the Nankai trough, Southwestern Japan","authors":"Y. Kaneda, E. Araki, H. Matsumoto, Takeshi Nakamura, S. Kamiya, K. Ariyoshi, T. Hori, M. Takahashi, T. Baba, M. Nakano, Jin-Kyu Choi, S. Nishida","doi":"10.1109/OCEANS-TAIPEI.2014.6964436","DOIUrl":"https://doi.org/10.1109/OCEANS-TAIPEI.2014.6964436","url":null,"abstract":"The Nankai trough is one of the largest and hazardous seismogenic zones in the world. Around the Nankai Trough, there are 3 mega thrust earthquake seismogenic zones such as the Tokai, Tonankai and Nakai seismogenic zones. Especially, the estimation of seismic linkage between the Tonankai and Nankai seismogenic zone is very important and indispensable for the reduction of earthquake and tsunami damages. Actually, the Tonankai and Nankai earthquake occurred in 1944/ 1946, 1854 as the seismic linkage events. Therefore, for understandings of early warning and prediction of erathquakes and tsunamis, the ocean floor network equipped with multi kinds of sensors such as seismometers and pressure gauges are very important and significant tool to monitor the broad band phenomena in the Nankai seismogenic zones. In the Tonankai seismogenic zone, we constructed DONET (Dense Ocean floor Network for Earthquakes and Tsunamis) with 20 observatories for early warning and improvement of prediction reliability. Multi kinds of sensors such as an accelerometer, a broad band seismometer, a precise pressure gauge, a differential pressure gauge and a precise thermometer are equipped in each observatory. Furthermore, the long term borehole observatory system with the seismometer, strainmeter, tiltmeter etc. is already installed in the drilled hole by IOPD NanTroSEIZE project, finally, this system will connect to DONET for the 3 dimensional real time monitoring. Now, we are already developing DONET2 with 31 observatories around the Nankai seismogenic zone and will complete deployments within 3 years. DONET2 system is more powerful rather than DONET system to monitor the large seismogenic zone areas. Especially, these offshore real time data will be applied to estimate of tsunami scales. We have to learn the lesson from tsunami damages of East Japan Earthquake 2011, Sumatra Earthquake 2004 etc. So, we are developing the advanced tsunami early estimation system using not only real time monitoring but also advanced simulation.","PeriodicalId":114739,"journal":{"name":"OCEANS 2014 - TAIPEI","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130228323","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}
Pub Date : 2014-04-07DOI: 10.1109/OCEANS-TAIPEI.2014.6964288
Huang Mei, Haixin Sun, Qi Jie, Xiaoyan Kuai, Gu Ye
Orthogonal frequency division multiplexing (OFDM) is a promising alternative modulation for underwater acoustic communication due to its ability in mitigating multipath effects. However, the high peak-to-average ratio (PAPR) constraints the power value level especially for long distance transmission. The problem of non-linear distortion generated by using one or more non-linear devices cannot be ignored when the OFDM signal is used to transmit. A novel clipping system model is proposed to simulate the effect of the non-linear distortion, which exploits the clipping operation to reduce the Peak-to-Average-Power-Ratio (PAPR). A new method based on compressed sensing (CS) is used to estimate the clipping values and compensate the effect of the non-linear distortion. It is shown that the clipping and compensation scheme can simulate the nonlinear distortion and significantly alleviate the distortion using CS compensation. The simulation and experiment results will verify the feasibility and advantages of the method.
{"title":"The clipping and nonlinear distortion compensation for underwater acoustic OFDM system","authors":"Huang Mei, Haixin Sun, Qi Jie, Xiaoyan Kuai, Gu Ye","doi":"10.1109/OCEANS-TAIPEI.2014.6964288","DOIUrl":"https://doi.org/10.1109/OCEANS-TAIPEI.2014.6964288","url":null,"abstract":"Orthogonal frequency division multiplexing (OFDM) is a promising alternative modulation for underwater acoustic communication due to its ability in mitigating multipath effects. However, the high peak-to-average ratio (PAPR) constraints the power value level especially for long distance transmission. The problem of non-linear distortion generated by using one or more non-linear devices cannot be ignored when the OFDM signal is used to transmit. A novel clipping system model is proposed to simulate the effect of the non-linear distortion, which exploits the clipping operation to reduce the Peak-to-Average-Power-Ratio (PAPR). A new method based on compressed sensing (CS) is used to estimate the clipping values and compensate the effect of the non-linear distortion. It is shown that the clipping and compensation scheme can simulate the nonlinear distortion and significantly alleviate the distortion using CS compensation. The simulation and experiment results will verify the feasibility and advantages of the method.","PeriodicalId":114739,"journal":{"name":"OCEANS 2014 - TAIPEI","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128009127","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}
Pub Date : 2014-04-07DOI: 10.1109/OCEANS-TAIPEI.2014.6964474
S. Nishida, K. Kawaguchi, T. Imaizumi, T. Akamatsu
DONET (Dense Ocean-floor Network system for Earthquakes and Tsunamis) is a submarine cabled real-time observation network for earthquakes and tsunamis monitoring around the Nankai trough, southwestern Japan. The scheduled twenty observatories have operated since August 2011. Various sensors such as a broadband seismometer, a pressure gauge, a hydrophone, etc. are equipped with each observatory, because DONET has expected to obtain the data to understand the Nankai trough mega thrust earthquake seismogenic zones. Therefore, in order to supply data stably, it's important to have a method of an investigation of the performance of each sensor in DONET. In this research, we will evaluate the performance of a hydrophone of DONET. The reference hydrophone was installed several meters from an observatory of DONET. Here, it assumes that both hydrophones will record the acoustic data according to same sound source. And, we will evaluate the performance of a hydrophone by the comparison between reference hydrophone and DONET's one in actual field, and will report the result of the evaluations.
{"title":"An evaluation of the performance of a hydrophone on sea floor","authors":"S. Nishida, K. Kawaguchi, T. Imaizumi, T. Akamatsu","doi":"10.1109/OCEANS-TAIPEI.2014.6964474","DOIUrl":"https://doi.org/10.1109/OCEANS-TAIPEI.2014.6964474","url":null,"abstract":"DONET (Dense Ocean-floor Network system for Earthquakes and Tsunamis) is a submarine cabled real-time observation network for earthquakes and tsunamis monitoring around the Nankai trough, southwestern Japan. The scheduled twenty observatories have operated since August 2011. Various sensors such as a broadband seismometer, a pressure gauge, a hydrophone, etc. are equipped with each observatory, because DONET has expected to obtain the data to understand the Nankai trough mega thrust earthquake seismogenic zones. Therefore, in order to supply data stably, it's important to have a method of an investigation of the performance of each sensor in DONET. In this research, we will evaluate the performance of a hydrophone of DONET. The reference hydrophone was installed several meters from an observatory of DONET. Here, it assumes that both hydrophones will record the acoustic data according to same sound source. And, we will evaluate the performance of a hydrophone by the comparison between reference hydrophone and DONET's one in actual field, and will report the result of the evaluations.","PeriodicalId":114739,"journal":{"name":"OCEANS 2014 - TAIPEI","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126315672","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}
Pub Date : 2014-04-07DOI: 10.1109/OCEANS-TAIPEI.2014.6964342
G. Page, S. Bainbridge, Scott Gardner, S. Hahn
This paper describes the design, installation and operation of a high-speed, real-time coral reef observing system network at Heron Island, within the Australian Great Barrier Reef. As part of the Queensland Integrated Marine Observing System (Q-IMOS) node of the Australian Integrated Marine Observing System (IMOS), a low data rate wireless sensor network has been operational at Heron Island since 2008. In 2013 a new surface reef pole and underwater cabled Ethernet network were installed on the edge of the Heron Island Reef lagoon, with telemetry back to the Heron Island Research Station achieved using a 300 Mbps wireless 802.11 link. The reef pole provides a network bridge to an underwater-cabled Ethernet network, and also provides an 802.11 wireless access point for the remainder of the Heron Island reef lagoon. Internet protocol networks provide for an extensible architecture, enabling the easy connection of any type of oceanographic instrument, camera or video system to the observing system. Acoustic monitoring receivers for fish tracking are connected to the network to allow for real-time monitoring. The underwater-cabled network is modular in design allowing for easy repair, expansion or reconfiguration of the network for any future requirements. This paper discusses the design considerations, system components and results of using affordable wireless 802.11 networks in a harsh marine environment for coral reef observing systems.
本文介绍了澳大利亚大堡礁Heron岛高速实时珊瑚礁观测系统网络的设计、安装和运行情况。作为澳大利亚综合海洋观测系统(IMOS)的昆士兰综合海洋观测系统(Q-IMOS)节点的一部分，自2008年以来，低数据速率无线传感器网络一直在Heron岛运行。2013年，在Heron Island reef lagoon的边缘安装了一个新的表面礁杆和水下有线以太网网络，通过300 Mbps的无线802.11链路实现遥测回Heron Island研究站。礁杆为水下有线以太网提供了一个网络桥梁，也为赫伦岛礁湖的其余部分提供了一个802.11无线接入点。互联网协议网络提供了一种可扩展的架构，使任何类型的海洋仪器、摄像机或视频系统能够轻松连接到观测系统。用于鱼类跟踪的声学监测接收器连接到网络，以便进行实时监测。水下电缆网络采用模块化设计，可以轻松修复、扩展或重新配置网络，以满足未来的任何需求。本文讨论了在恶劣的海洋环境中使用价格合理的无线802.11网络用于珊瑚礁观测系统的设计考虑、系统组成和结果。
{"title":"Development of a coral reef observing system using 802.11 wireless at Heron Island, Great Barrier Reef","authors":"G. Page, S. Bainbridge, Scott Gardner, S. Hahn","doi":"10.1109/OCEANS-TAIPEI.2014.6964342","DOIUrl":"https://doi.org/10.1109/OCEANS-TAIPEI.2014.6964342","url":null,"abstract":"This paper describes the design, installation and operation of a high-speed, real-time coral reef observing system network at Heron Island, within the Australian Great Barrier Reef. As part of the Queensland Integrated Marine Observing System (Q-IMOS) node of the Australian Integrated Marine Observing System (IMOS), a low data rate wireless sensor network has been operational at Heron Island since 2008. In 2013 a new surface reef pole and underwater cabled Ethernet network were installed on the edge of the Heron Island Reef lagoon, with telemetry back to the Heron Island Research Station achieved using a 300 Mbps wireless 802.11 link. The reef pole provides a network bridge to an underwater-cabled Ethernet network, and also provides an 802.11 wireless access point for the remainder of the Heron Island reef lagoon. Internet protocol networks provide for an extensible architecture, enabling the easy connection of any type of oceanographic instrument, camera or video system to the observing system. Acoustic monitoring receivers for fish tracking are connected to the network to allow for real-time monitoring. The underwater-cabled network is modular in design allowing for easy repair, expansion or reconfiguration of the network for any future requirements. This paper discusses the design considerations, system components and results of using affordable wireless 802.11 networks in a harsh marine environment for coral reef observing systems.","PeriodicalId":114739,"journal":{"name":"OCEANS 2014 - TAIPEI","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125889726","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}
Pub Date : 2014-04-07DOI: 10.1109/OCEANS-TAIPEI.2014.6964410
E. Araki, T. Kimura, S. Kodaira, S. Miura, M. Takaesu, N. Takahashi, M. Nakano, Y. Kaneda
An experiment was performed to shoot airgun and receive the seismic signal with long-term seafloor seismic observatories (DONET seafloor and IODP borehole observatory) above the seismogenic zone in the Nankai Trough. The purpose of the experiment is to assess possibility to detect temporal change in seismic velocity structure which might change due to the stress accumulation in and around the subducting seismogenic plate interface, by repeated airgun survey, as well as to evaluate present stress state in the area through seismic anisotropy. The initial analysis of the experiment suggests that airgun shooting in accurate position especially in terms of the distance from the receiving observatory is necessary to treat the repeated shot record as the shooting in the same condition. P-wave first motion data from a circle shooting around the borehole observatory showed clear azimuthal dependency when correction was made for seafloor topography variation, which was consistent with known other indicators for seismic anisotropy and stress state.
{"title":"Experiment to detect temporal change of seismic velocity in the subducting plate boundary in the Nankai Trough using the DONET submarine cabled observation network and airgun controlled source","authors":"E. Araki, T. Kimura, S. Kodaira, S. Miura, M. Takaesu, N. Takahashi, M. Nakano, Y. Kaneda","doi":"10.1109/OCEANS-TAIPEI.2014.6964410","DOIUrl":"https://doi.org/10.1109/OCEANS-TAIPEI.2014.6964410","url":null,"abstract":"An experiment was performed to shoot airgun and receive the seismic signal with long-term seafloor seismic observatories (DONET seafloor and IODP borehole observatory) above the seismogenic zone in the Nankai Trough. The purpose of the experiment is to assess possibility to detect temporal change in seismic velocity structure which might change due to the stress accumulation in and around the subducting seismogenic plate interface, by repeated airgun survey, as well as to evaluate present stress state in the area through seismic anisotropy. The initial analysis of the experiment suggests that airgun shooting in accurate position especially in terms of the distance from the receiving observatory is necessary to treat the repeated shot record as the shooting in the same condition. P-wave first motion data from a circle shooting around the borehole observatory showed clear azimuthal dependency when correction was made for seafloor topography variation, which was consistent with known other indicators for seismic anisotropy and stress state.","PeriodicalId":114739,"journal":{"name":"OCEANS 2014 - TAIPEI","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127563951","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}
Pub Date : 2014-04-07DOI: 10.1109/OCEANS-TAIPEI.2014.6964463
G. Too, Yi-Wei Lin, Yuhong Ke
In the shallow water environment, detecting and classifying buried objects is a challenging problem with high operational importance. Acoustical wave becomes an important tool in the detection of objects in underwater systems due to its effectiveness of propagation in the water. Later on, the acoustic scattered field modal for fluid-loaded and thin spherical shell have been determined by the shell's physical properties and appropriate boundary conditions at the fluid interface. These spherical elastic shells produce lamb waves that contain energy within corresponding frequency bandwidth. The iterative time reversal process is then performed to enhance energy of responding lamb waves and makes it possible to distinguish target characteristics. In addition, target distance can be determined from wave propagation time. The study is developing a procedure to distinguish target characteristics such as material and size by observing convergence frequency through iterative time reversal process. The proposed procedure is verified from designed simulations and experiments by using spherical elastic shells as targets. In experiments, interrogating signals are transmitted from an unfocused broadband underwater transducer and recorded received by another same type transducer. Due to the enhancing effect of iterative time reversal, energy of iterative receiving signals converges to certain frequencies. After comparing these frequencies from varying target characteristics such as diameter of target sphere shell and thick of target sphere shell, the result proves that the proposed procedure is capable to distinguished properties of different targets.
{"title":"Echoes analysis from spherical elastic shells by using iterative time reversal mirror","authors":"G. Too, Yi-Wei Lin, Yuhong Ke","doi":"10.1109/OCEANS-TAIPEI.2014.6964463","DOIUrl":"https://doi.org/10.1109/OCEANS-TAIPEI.2014.6964463","url":null,"abstract":"In the shallow water environment, detecting and classifying buried objects is a challenging problem with high operational importance. Acoustical wave becomes an important tool in the detection of objects in underwater systems due to its effectiveness of propagation in the water. Later on, the acoustic scattered field modal for fluid-loaded and thin spherical shell have been determined by the shell's physical properties and appropriate boundary conditions at the fluid interface. These spherical elastic shells produce lamb waves that contain energy within corresponding frequency bandwidth. The iterative time reversal process is then performed to enhance energy of responding lamb waves and makes it possible to distinguish target characteristics. In addition, target distance can be determined from wave propagation time. The study is developing a procedure to distinguish target characteristics such as material and size by observing convergence frequency through iterative time reversal process. The proposed procedure is verified from designed simulations and experiments by using spherical elastic shells as targets. In experiments, interrogating signals are transmitted from an unfocused broadband underwater transducer and recorded received by another same type transducer. Due to the enhancing effect of iterative time reversal, energy of iterative receiving signals converges to certain frequencies. After comparing these frequencies from varying target characteristics such as diameter of target sphere shell and thick of target sphere shell, the result proves that the proposed procedure is capable to distinguished properties of different targets.","PeriodicalId":114739,"journal":{"name":"OCEANS 2014 - TAIPEI","volume":"227 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122351237","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}
Pub Date : 2014-04-07DOI: 10.1109/OCEANS-TAIPEI.2014.6964361
Mengnan Sun, Bing Zheng, Lifeng Zhao, Jia Yu
The combination of ROV and the seafloor-based sensors networks has become a mainstream medium to explore the world under water. As the task becomes more diversified, the data volume of the communication between the ROV and the sensor node grows increasingly. Although the light can not perform the long-distance propagation as the acoustic signal under water, with the high bandwidth speciality of optical communication, it is absolutely feasible to acquire a highspeed information interaction in short range. To achieve this goal, this paper aims to pay a way of an ROV equipped with a function of underwater laser communication system. In this paper, following the principle of ”bottom to top, analog to digital, low speed to high speed”, our novel ROV design with a laser communication system and its configuration was presented, and a simple analog communication link was built to test the feasibility, then the digital communication protocol RS-232 was applied to this link. Experiment results showed that in short rang, a highspeed and low-BER laser communication link under water was feasible.
{"title":"Paying a way of the ROV equipped with a function of underwater laser communication","authors":"Mengnan Sun, Bing Zheng, Lifeng Zhao, Jia Yu","doi":"10.1109/OCEANS-TAIPEI.2014.6964361","DOIUrl":"https://doi.org/10.1109/OCEANS-TAIPEI.2014.6964361","url":null,"abstract":"The combination of ROV and the seafloor-based sensors networks has become a mainstream medium to explore the world under water. As the task becomes more diversified, the data volume of the communication between the ROV and the sensor node grows increasingly. Although the light can not perform the long-distance propagation as the acoustic signal under water, with the high bandwidth speciality of optical communication, it is absolutely feasible to acquire a highspeed information interaction in short range. To achieve this goal, this paper aims to pay a way of an ROV equipped with a function of underwater laser communication system. In this paper, following the principle of ”bottom to top, analog to digital, low speed to high speed”, our novel ROV design with a laser communication system and its configuration was presented, and a simple analog communication link was built to test the feasibility, then the digital communication protocol RS-232 was applied to this link. Experiment results showed that in short rang, a highspeed and low-BER laser communication link under water was feasible.","PeriodicalId":114739,"journal":{"name":"OCEANS 2014 - TAIPEI","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126103140","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}
Pub Date : 2014-04-07DOI: 10.1109/OCEANS-TAIPEI.2014.6964569
J. Hermand, Longxiang Guo, J. Randall, P. Brehmer
A submersible digital holographic microscope (DHM) Holoflow@Sea was deployed during AWA fisheries surveys conducted in March 2013 and 2014 in the large upwelling ecosystem of the Canaries Current. The microscope collected about half a million of holograms of microorganisms and other particles suspended in the water column. Selected new results of reconstruction of phyto- and zooplankton species using improved algorithms with respect to previously published results are presented. Amplitude images are more detailed and, for some species, phase images provide useful additional information about morphology and composition. Extensive analysis confirms that the submersible DHM is suitable for in-situ imaging of organisms in the size range 2 μm-200 μm and species identification. When compared to standard procedures the microscope allows to rapidly monitor planktonic communities over a wide area. It contributes to a better understanding of the organization and functioning of the ecosystem and in particular the link between biogeochemistry cycles and small pelagic fish stock dynamics.
{"title":"Non-destructive optical holographic imaging of microorganisms in situ off the Senegalese coast","authors":"J. Hermand, Longxiang Guo, J. Randall, P. Brehmer","doi":"10.1109/OCEANS-TAIPEI.2014.6964569","DOIUrl":"https://doi.org/10.1109/OCEANS-TAIPEI.2014.6964569","url":null,"abstract":"A submersible digital holographic microscope (DHM) Holoflow@Sea was deployed during AWA fisheries surveys conducted in March 2013 and 2014 in the large upwelling ecosystem of the Canaries Current. The microscope collected about half a million of holograms of microorganisms and other particles suspended in the water column. Selected new results of reconstruction of phyto- and zooplankton species using improved algorithms with respect to previously published results are presented. Amplitude images are more detailed and, for some species, phase images provide useful additional information about morphology and composition. Extensive analysis confirms that the submersible DHM is suitable for in-situ imaging of organisms in the size range 2 μm-200 μm and species identification. When compared to standard procedures the microscope allows to rapidly monitor planktonic communities over a wide area. It contributes to a better understanding of the organization and functioning of the ecosystem and in particular the link between biogeochemistry cycles and small pelagic fish stock dynamics.","PeriodicalId":114739,"journal":{"name":"OCEANS 2014 - TAIPEI","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127650930","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}
Pub Date : 2014-04-07DOI: 10.1109/OCEANS-TAIPEI.2014.6964458
C. Yun, N. Ko, Yongseon Moon, Hyun-Taek Choi
This paper describes a development of a broad band underwater acoustic transducer for Doppler Velocity Log(DVL). The transducer uses thickness vibration mode of a disk type piezoelectric(PZT) ceramic. Three types of transducers, each having different configuration of acoustic impedance matching layer and backing are composed. Transmitting voltage response(TVR), receiving voltage sensitivity(RVS) and bandwidth of the transmission for the three types of acoustic transducers are evaluated. The test shows that the transducer with the configuration of three matching layers and a lossy backing results the best performance among the three types. From the test results, the effects of the acoustic impedance matching layer and backing are discussed.
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