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The recognition of objects and environment are one of keys to automate underwater tasks. This paper presents a predictor based image recognition method using high-resolution sonar images. They are very sensitive to sonar's view point changes. The proposed predictor predicts an object images depending on the view point. Using the object model, it modifies a template for optimal recognition. To estimate...
The underwater multi-agent technology using many types of underwater robot has great potential for various underwater activities in the near future. To realize the underwater multi-agent system, we must experience many situations and problems to be solved in that development by using real systems as well as the computer simulations. So we are now building basic systems of basin experiment for the...
In most robotic swarming applications each individual needs to know the positions and orientations of at least its near neighbours. One way of achieving this local estimate underwater is by means of wide-bandwidth acoustic signals of specific statistical characteristics (maximum length sequence -MLS). The principal capability of local posture estimation has been demonstrated. While previous results...
The goal of this ambitious project is to provide the oceanographic research community with the first capable and cost-effective technology for regular and systematic access to the world's oceans to 11,000 meters. The vehicle, named after the Greek mythical God Nereus, will be able to operate untethered as a fully autonomous vehicle, and also as a self-powered vehicle employing a 3 mm diameter optical...
Reliable wireless communication underwater is a precondition for swarming technologies. This paper discusses a time division multiple access (TDMA) algorithm suitable for dynamic multi-hop wireless networks, which offers quick all-to-all information exchange (Omnicast), dense local schedules and predictable latencies. The algorithm is based on an earlier algorithm published by the authors in [Schill...
We have developed and demonstrated a borehole seismometer using a laser interferometer. With a low-frequency pendulum and feedback circuits, broadband response for long-period seismic waves can be obtained. Test observation data of the seismometer installed in a 10-m-deep borehole on land showed good agreement with data from a conventional land-based broadband seismometer above ~30 mHz. At lower frequencies,...
Eight cabled observatories are all installed to aid earthquake studies for disaster mitigation at the future potential hazards that could take place at plate boundaries surrounding the Japanese islands. Scientific results started appearing in the literature using passive, real-time and continuous time series of data acquired on the seafloor for seismic and tsunami signals. The knowledge about earthquake...
This poster explores modifications to the design, fabrication and implementation of the field tested prototype Free Ocean CO2 Enrichment (FOCE) system. The proof of concept prototype system was able in the field to control pH perturbations from acid release simulating CO2 induced pH changes in specific habitat experiments. The acidified flow was pumped so as to maintain a constant delta pH under varying...
An ocean bottom cable system (OBCS) is the best solution for monitoring the tectonic activities in a seismogenic zone. However the number of seismometers of the existing OBCS is insufficient for high resolution observation of the seismogenic zone, because the cost of the OBCS has been very expensive. In order to solve this problem, the authors have studied new cost effective OBCSs with 40 seismic...
The first long time monitoring of O2 dynamics at sediment-water interface (SWI) was conducted using with a newly developed planar O2 optode system for in situ measurement. The monitoring was carried out connecting the optode system with Hatsushima permanent station with a 100 meter-long extension cable under supporting by the operation of ROV Hyper-dolphin. The monitoring was successfully carried...
Sound waves are highly conductive in the ocean; therefore, they are used in various aspects of underwater applications like, environment exploration, underwater target detection and signal transmission. For all these applications, underwater acoustic signal logging is one of the key elements of the system. In laboratory setup, data recorders are often configured on a single-board computer, industrial...
For many undersea research application scenarios, instruments need to be deployed for more than one month which is the basic time interval for many phenomena. With limited power supply and memory, management strategies are crucial for the success of data collection. For acoustic recording of undersea activities, in general, either preprogrammed duty cycle is configured to log partial time series,...
The maximum likelihood method (MLM) of bottom detection allows substantial reduction in the minimum acceptable SNR in outer beams and, as a result, widening of the survey swath in deep water multi-beam echo sounder (MBES) applications. In this discussion, the arrays are installed in a Mills Cross configuration, with the transmit array oriented along-track and the receive array oriented across-track...
Stationary underwater cameras were deployed to evaluate spatial and temporal distribution of fish assemblage inhabiting a high-rise artificial reef. The camera named FISCHOM has a stereo camera or a monaural camera on board and it can operate periodically by an arbitrary interval. We can acquire the information about fish fauna and fish size distribution and their time series of reef fish assemblages...
The authors developed several types of robotic fish that swim with fins that apply flexible oscillating fin technology. The new type one is the Carp Robot, whose artificial appearance was created through three-dimensional CAD processing of numerical data for the outer shape of living carp sampled through three-dimensional laser measurements. Although these types of robotic fish were developed for...
The inspection of coastal and offshore structures is important for their life cycle assessment. We have been developing an underwater vehicle equipped with two pairs of mechanical pectoral fins for this mission. If underwater vehicles are used as an automatic inspection system, the determination of the desired levels of guidance and control law for the underwater vehicle is essential. However, since...
A parametric study on random internal waves in a two-fluid system is carried out in this paper. Based on the existing study provided by the author, the second-order theory for the interaction of arbitrary two linear waves is adopted to examine its influence on wave profiles. Two modes of wave motion are investigated: the surface (fast) mode and the internal (slow) mode. On the basis of present results,...
A device for transferring wave-dissipating blocks was developed using net chains to allow for automation and labor saving. The device spreads net chains over a block and then tightens the net chains using a wire rope connected to a crane to lift the block. A model device was used to conduct a transfer experiment under several visibility conditions. A practical device was produced, and transfer work...
The underwater security sonar system is the port surveillance system which surveys over harbors and ships in order to protect harbor facilities such as wharfs, oil refineries, airports and vehicles, from the terrorism attack under or on the sea. For our surveillance system, it is required to develop the software which can perform "automatic detection of doubtful target" by processing the...
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