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Proceedings of 1998 International Symposium on Underwater Technology

17-17 April 1998

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Displaying Results 1 - 25 of 87
  • Proceedings of 1998 International Symposium on Underwater Technology

    Publication Year: 1998
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    Freely Available from IEEE
  • Author's index

    Publication Year: 1998, Page(s):xxi - xxiii
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  • Autonomous vehicle obstacle detection and tracking

    Publication Year: 1998, Page(s):198 - 202
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (364 KB)

    Almost all autonomous underwater vehicles require some manner of acoustic obstacle detection and avoidance mechanism to prevent vehicle damage due to collisions with uncharted obstacles. Modern forward looking multi-beam sonars use wide bandwidth pulses, fast sampling rates, and high bit count samples to form simultaneous beams having wide dynamic range and good target to clutter ratios. As a resu... View full abstract»

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  • The development of ROVs and training experts in the field of underwater robotics in Far-Eastern State Technical University

    Publication Year: 1998, Page(s):78 - 83
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (940 KB)

    The purpose of the present report is an account of the generalized experience of a completed underwater remotely operated vehicles (ROVs) for experts training at the Far Eastern State Technical University View full abstract»

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  • Autonomous target tracking by underwater robots based on vision

    Publication Year: 1998, Page(s):191 - 197
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (760 KB)

    This paper proposes and demonstrates the performance of a target tracking system designed for underwater robots (UR) based on the image data of the target, captured by a single CCD camera mounted on the robot. The use of target features for the derivation of navigational commands for the UR is addressed. The proposed system simplifies the underwater navigation problem by introducing additional par... View full abstract»

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  • Deep sea research effort of Japan focused on oceanic lithosphere dynamics

    Publication Year: 1998, Page(s):55 - 60
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1356 KB)

    Recent scientific seafaring activities of Japan in the solid Earth sciences are described. The main workers in this field are the Ocean Research Institute, University of Tokyo and Japan Marine Science and Technology Center. The framework of the research is focused mostly on the dynamic behavior of the oceanic lithosphere. Special interests are focused on the birth, growth and death of the oceanic ... View full abstract»

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  • Compensation of multipath fading in underwater spread-spectrum communication systems

    Publication Year: 1998, Page(s):453 - 458
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (504 KB)

    Techniques for achieving reliable communications over underwater acoustic channels are investigated in this work. We consider implementation of an underwater spread-spectrum communication system. To compensate the multipath fading and Doppler effects in the underwater acoustic channel, a transform-domain approximate RLS (TARLS) blind equalizer is incorporated in the receiver. The computational com... View full abstract»

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  • Intelligent control system for 6000 m deep towed system

    Publication Year: 1998, Page(s):75 - 77
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (192 KB)

    In this paper, intelligent control is employed to tackle the movement control problems of a 6000 m deep towed system. First, the dynamic response of the 6000 m deep towed system is analyzed. Then, an intelligent control system using the adaptive neural network is proposed, and the learning control algorithm is given. Finally, results of the movement control of the 6000 m deep towed system are disc... View full abstract»

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  • Experimental observations of vertical and horizontal distribution of total suspended sediment using high frequency acoustic backscattering technique

    Publication Year: 1998, Page(s):21 - 26
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (372 KB)

    Accumulation of heavy metals such as Hg and Cd is increasingly becomes a critical environmental concern, especially when they enter into higher food chains and are consumed by humans. It has been identified that these heavy metals are attached to a particle or aggregate of particles in the water column. This fact prompted a need for a better understanding of the dynamics of these particles in orde... View full abstract»

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  • Optically-linked laser-interferometric tiltmeter for ocean borehole observations

    Publication Year: 1998, Page(s):168 - 171
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (364 KB)

    We have developed a borehole tiltmeter based on laser interferometry. Its principle is based on a simple pendulum whose horizontal 2D motion is detected by laser interferometers with high sensitivity. The laser light is introduced from outside the borehole through an optical fiber, and the observed signals are also led through optical fibers out of the borehole; the borehole sensor is optically-li... View full abstract»

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  • Tools and techniques for deep water sediment sampling around a ship wreck

    Publication Year: 1998, Page(s):7 - 10
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (676 KB)

    In August 1997, a series of near-bottom operations were conducted in an acoustic transponder net deployed around the wreck of the ex USS-Agerholm, about 130 nm offshore Southern California in 800 m of water depth. The Marine Physical Laboratory's Deep Tow Control Vehicle equipped with two orthogonal horizontal thrusters, a sector scanning sonar, cameras, lights, a navigation sonar, and an altimete... View full abstract»

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  • A plan of utilization of AUVs in shallow water

    Publication Year: 1998, Page(s):155 - 158
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (804 KB)

    The usual AUVs are aiming at the use in deep water. However, in port area where the water depth is shallow, the practical use of AUVs can be considered because of the recent progress of AUV technology. We made plan to develop the omnidirectional AUV for port facility inspection. The first test model was manufactured and experiment is started View full abstract»

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  • The development of underwater dredging system for rocky sea bottom at narrow channel

    Publication Year: 1998, Page(s):340 - 345
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (548 KB)

    Kanmon channel located between Honshu and Kyusyu is a main steamship lane of Japan. On March 1991 the dredging plan to the depth of 14 m was decided. The part of Hayatomo-Strait is restricted by various conditions. At present, dredging to the depth of -13 m, to the distance of 100 m from the side end of the channel, we use a grab dredger which is equipped with spades and anchor lines for mooring. ... View full abstract»

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  • Estimating the sea current and finding the optimal heading of an AUV through neural network motion control

    Publication Year: 1998, Page(s):239 - 243
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (440 KB)

    For an autonomous underwater vehicle (AUV), sea current is an unknown varying parameter which can not be given before operation and which may impose significant influence on the performance of an AUV. Furthermore, it is difficult to measure the sea current from a moving or suspending AUV. This paper presents a technique for automatically estimating the sea current and finding the optimal heading t... View full abstract»

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  • On the prediction of manoeuvrability of the autonomous underwater vehicle, AUV-HM1

    Publication Year: 1998, Page(s):185 - 190
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (492 KB)

    The manoeuvrability of the unmanned untethered submersible AUV-HM1 testbed developed at the Department of Naval Architecture and Ocean Engineering of National Taiwan University is investigated through two sets of stability indices, one is evaluated by the estimated values of stability derivatives, the others are those obtained by a series of captive model tests. Those results presented in the prev... View full abstract»

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  • Evaluation of a synthetic aperture sonar with a multi-aperture transducer

    Publication Year: 1998, Page(s):487 - 492
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (492 KB)

    This paper presents a synthetic aperture sonar with a multi-aperture transducer. The pulse repetition frequency (PRF) is automatically modified so that conditions for both maximum search range and azimuth resolution are simultaneously satisfied. The PRF modification makes the ratio of two aperture lengths an integer, each of which is obtained for the above two conditions. Consequently, unnecessary... View full abstract»

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  • Shallow water bathymetric data improvement in SeaBeam 2100 multibeam systems

    Publication Year: 1998, Page(s):299 - 303
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (336 KB)

    SeaBeam 2100 is a new generation multibeam sonar capable of mapping the ocean floor with swath coverage ranging from ±75° in shallow waters to ±45° for the deepest ocean floor. Since the main design goal was to attain full ocean depth capability, array sizes are large and as a consequence the near-field effect moderates the performance of the systems in shallow waters. Improv... View full abstract»

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  • Effect of a transition density layer on wave propagation in a seismo-acoustic ocean waveguide

    Publication Year: 1998, Page(s):47 - 52
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (468 KB)

    The effect of a transition density layer on the wave propagation in an oceanic environment is studied. The reflection characteristics from a medium containing a density transition layer overlying on a uniform fluid/elastic layer such as seabed are first examined, followed by a study of surface noise propagation in a waveguide environment. The results have shown that the effect of density transitio... View full abstract»

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  • Experimental verification for the control system of intelligent underwater vehicle

    Publication Year: 1998, Page(s):472 - 477
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (416 KB)

    This paper introduces an intelligent underwater vehicle and describes the architecture of the control system, especially the mission execution module. An artificial neural network is used to deal with the nonlinear dynamics of underwater vehicle and the unpredictable disturbances. Performances of the system on motion control, autonomous navigation and obstacle avoidance were tested by a series of ... View full abstract»

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  • Optimizing the directivity diagram of underwater acoustic wide band antennas

    Publication Year: 1998, Page(s):93 - 97
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    We describe the development of multisensor antennas in a specified band of frequencies using beamforming and processing techniques. This method is based on the spatial positioning of omnidirectional transducers and the use of specific professing in order to maintain the directivity diagram constant over the whole frequency band of interest. The digital signal processing algorithms associated with ... View full abstract»

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  • A new high accuracy super-short baseline (SSBL) system

    Publication Year: 1998, Page(s):210 - 215
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (348 KB)

    This paper describes an acoustic super short baseline (SSBL) tracking system capable of tracking up to twenty targets simultaneously, accurately and at long ranges. The design of the hydrophone array is similar to that of conventional SSBL arrays, but uses greater inter-element separation to provide much better tracking accuracy. With this design, the bearing and elevation of targets at ranges gre... View full abstract»

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  • ROVs and undersea cable maintenance

    Publication Year: 1998, Page(s):69 - 74
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB)

    The number of remotely operated vehicles (ROVs), as well as their potential uses, have increased over the years since they were first conceptualized. As the number of installed undersea cables continue to increase, the potential for external aggression relating to these cables increases. Today, it is essential that each cable through its associated maintenance agreement have access to a remotely o... View full abstract»

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  • Design and testing of an underwater microscopy for the study of zooplankton distribution

    Publication Year: 1998, Page(s):17 - 20
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (340 KB)

    A method that can monitor zooplankton density at adequate spatio/temporal resolution is desired in the field of oceanic ecosystem studies. We have developed a submergible microscope equipped with a noninterlace CCD camera. As target plankton, ploima, cladocera, calanoida, cyclopoida, ciliata are selected. Those are dominant species in the coastal sea around Japan. Requirements of a system for an u... View full abstract»

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  • Underwater laser viewing system and its application

    Publication Year: 1998, Page(s):161 - 167
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (888 KB)

    Viewing through turbid water, which is obstructed by the mixture of scattered rays prematurely reflected backward from intervening suspended articles and reflected forward from such particles after impinging on the viewed object, is improved by adopting the range gate camera, combined with pulsed illumination of the viewed object by laser rays. The range gate camera opens its shutter only during t... View full abstract»

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  • Results of the Naval Oceanographic Office's 1997 AUV workshop

    Publication Year: 1998, Page(s):115 - 120
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1028 KB)

    The US Navy has been developing autonomous underwater vehicles (AUVs) for operational scenarios for many years. The maturity of this technology has reached a point where it is both feasible and economical to transition AUVs to the collection of environmental data for the Navy. With this in mind, the Naval Oceanographic Office (NAVOCEANO) has established an AUV program with the goal of matching dif... View full abstract»

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