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We present wireless optical communication system for data transfer in the underwater networks. We use the optical channel to facilitate the communication link in free space and under water. This work bypasses the limitations involved in the use of electromagnetic waves and acoustics for free space and underwater communication. The system shows that optical communication using light can be a viable...
Seawater chlorophyll-a (Chla) represents algal biomass in ocean and is a major index of eutrophication. In this paper, bootstrapped artificial neural network (BANN) model is developed for predicting the seawater Chla concentration around the north Pacific Rim. Three-layer ANN structure is applied and the modeling is based on comprehensive five-minute interval datasets of water temperature, depth,...
The purpose of this research is to develop a solar-powered autonomous surface vehicle (SASV) for the use of ocean environment monitoring and underwater passive acoustic monitoring of marine mammals. Measuring items of the logger version CTD with optical fast DO sensor are depth, temperature, conductivity, salinity, dissolved oxygen, chlorophyll and turbidity. The authors have also developed kinds...
Precise understanding of the sea bottom characteristics and accurate identification of objects on the seabed are critical in many underwater applications. The severe multi-path along with the time varying and random reflections from the surface and the bottom of shallow waters, present an interesting and complex signal processing problem. A thin line hydrophone array, deployed from small Autonomous...
We have developed an automated cable-laying system that is operated with a remotely operated vehicle (ROV) and can automatically dispense a thin optical-fiber submarine cable at a rate that keeps pace with the ROV's ground speed. The use of an ROV allows to install a thin optical-fiber submarine cable on the deep seafloor accurately and safely. The ROV-based automated cable-laying system is being...
Damutu Bay in eastern Zhejiang, China has abundant tidal flat resources for years of silt deposition in the wide open seas, making it an ideal place for mudflat reclamation. In this study we set up a two-dimensional hydrodynamic and sediment transport model based on Mike 21 FM to investigate changes in suspended sediment concentration (SSC) after reclaiming to 1 m and 3 m depth contours in the seas...
This paper proposes visual-based underwater vehicle docking/homing system under the environment especially simulated for deep sea trial. Instead of measuring absolute position of vehicle using other non-contact sensors, estimation of the robot's relative position and posture (pose) using dual-eyes cameras and 3D target object is proposed. For relative pose estimation, 3D model-based recognition approach...
Thermocline has a significant impact on marine fishery, navy submarine activity, ocean circulation and internal wave. In consideration of long range, low cost, and high maneuverability, the AUV (Autonomous Underwater Vehicle) is an ideal platform for ocean local precisely thermocline tracking. Combining with the advantage of the AUV yo-yo movement, this paper presents a simple and effective thermocline...
In this paper, we present a simulation environment for marine robotics with support for swarm robotics and environmental monitoring. A vegetation system and fish swarms in the environment model present indirect bio-feedback. This enables the evaluation of swarm behaviors, e.g. to efficiently cover a vegetation area or monitor and chase fish swarms. The temperature sensor in the sensor model has a...
In underwater wireless optical communications (UWOC), impulse response is important to characterize channel properties. In this paper, we consider the impulse response for UWOC multiple-input single-output (MISO) links with a uniform circular array (UCA) of light sources. The Monte Carlo approach is adopted to achieve the impulse response of UWOC MISO links for the turbid water environment. We propose...
Ocean Environmental data is a key component utilized by the United States Coast Guard (USCG) when developing and executing a search and rescue mission. The Search and Rescue Optimal Planning System (SAROPS) became operational with the USCG in 2007 and is the main tool for developing search and rescue mission plans. This tool utilizes environmental data (wind, ocean currents, etc.) to estimate the...
Most studies on zooplankton image processing are focused on global texture feature. In this paper, an efficient method for classifying zooplankton images by combination of local binary pattern (LBP) is demonstrated. The classification performance of plankton image with global and local features have been evaluated and the overall performance of combination of these features for zooplankton identification...
For power supply of autonomous underwater vehicles (AUV), a novel underwater contactless power transmission (CPT) system based on the arc electromagnetic coupler (EC) is proposed in this paper. The equivalent circuit model of EC is established to analyze the transmission efficiency theoretically, thus the working frequency and the load resistance are optimized. Then the additional eddy current (AEC)...
In these decades, great interest has been directed toward high frequency surface wave radars (HFSWR) as long range early warning tools in maritime surveillance. But HFSWR exhibit some shortcomings that need to be taken into account when detecting targets, such as poor azimuth resolution and significant presence of clutter. This paper aims at showing a potential application of multi-frequency HFSW...
In this paper, we present some of the results of the Tallinn trials. The trials were part of the ARROWS (ARchaeological RObot systems for the World's Seas) FP7 project whose aims are to reduce the cost of the AUVs and sensors in order to generalize their use for underwater archaeological missions. To this end, we developed algorithms to improve the imagery resolution of wideband sonar systems with...
In this paper, we discuss the PAS (Pulse Active Sonar) and CAS (Continuous Active Sonar) strategies for target detection and tracking. CAS system potentially offer several advantages over traditional PAS systems, mainly in term of probability of detection and/or tracking. With a continuous insonification of the target, CAS can track continuously limiting the data association error inherent to PAS...
Based on Gibbs sampling technology, this paper puts forward a new semi-blind joint channel estimation and equalization algorithm that used in signal carrier coherent underwater acoustic communication system. First of all, we estimate the channel by using the train sequence with a loop structure before the data, and according to the sparse characteristics of underwater acoustic channel, this paper...
The numerical study on the effect of flapping foils with a modified shape on efficiently bio-mimetic propulsion is presented. A symmetric 4-digit NACA0006 foil was used as a baseline in this work, the design of modified foils were derived by altering NACA0006 foil leading section as thicker NACA foil's counterparts and keeping its trailing section unchanged, and as a result, the modified foils were...
Side scan sonar has been widely used in ocean investigations, underwater object detection by side scan sonar is one of the most essential and fundamental tasks these years. In this paper, we present one simplified underwater object detection scheme with the help of shadow removal of side scan sonar images. The fuzzy C-mean clustering (FCM) algorithm is first taken to partition all pixels from the...
This work controlled a robotic fish swimming alongside a wall. Research shows that fish swimming alongside a wall use lateral lines to obtain nearfield information. This concept is also applicable in man-made underwater vehicles such as robotic fish, which mimic the swimming action of a fish. Pressure sensors on the surface of a robotic fish measure hydrodynamic pressure variation. According to two-dimensional...
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