Now showing items 568-587 of 843

  • A parallel hypothesis method of autonomous underwater vehicle navigation 

    LaPointe, Cara Elizabeth Grupe (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2009-06)
    This research presents a parallel hypothesis method for autonomous underwater vehicle navigation that enables a vehicle to expand the operating envelope of existing long baseline acoustic navigation systems by incorporating ...
  • Particle fluxes associated with mesoscale eddies in the Sargasso Sea 

    Buesseler, Ken O.; Lamborg, Carl H.; Cai, Pinghe; Escoube, Raphaelle; Johnson, Rodney J.; Pike, Steven M.; Masque, Pere; McGillicuddy, Dennis J.; Verdeny, E. (2007-09-25)
    We examined the impact of a cyclonic eddy and mode-water eddy on particle flux in the Sargasso Sea. The primary method used to quantify flux was based upon measurements of the natural radionuclide, 234Th, and these flux ...
  • Passive acoustic detection of deep-diving beaked whales 

    Zimmer, Walter M. X.; Harwood, John; Tyack, Peter L.; Johnson, Mark P.; Madsen, Peter T. (Acoustical Society of America, 2008-11)
    Beaked whales can remain submerged for an hour or more and are difficult to sight when they come to the surface to breathe. Passive acoustic detection (PAD) not only complements traditional visual-based methods for detecting ...
  • A passive capture latch for ODYSSEY-class AUVs 

    Bowen, Martin F. (Woods Hole Oceanographic Institution, 1998-06-12)
    Under subcontract to the Massachusetts Institute of Techology's (MIT) Sea Grant Autonomous Ocean Sampling Network (AOSN) program, the Woods Hole Oceanographic Institution's Deep Submergence Laboratory (WHOI-DSL) produced ...
  • Passive localization of underwater acoustic beacons 

    Wojcik, Dennis M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1993-09)
    This thesis examines the use of a single, omnidirectional hydrophone as a receiving sensor to passively localize an acoustic beacon. The localization problem is presented as a constrained, nonlinear parameter estimation ...
  • Passive time reversal acoustic communications through shallow-water internal waves 

    Song, Aijun; Badiey, Mohsen; Newhall, Arthur E.; Lynch, James F.; DeFerrari, Harry A.; Katsnelson, Boris G. (IEEE, 2010-11-30)
    During a 12-h period in the 2006 Shallow Water Experiment (SW06), binary phase shift keying (BPSK) signals at the carrier frequencies of 813 and 1627 Hz were propagated over a 19.8-km source–receiver range when a packet ...
  • Passive wake detection using seal whisker-inspired sensing 

    Beem, Heather R. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2015-02)
    This thesis is motivated by biological experiments, which display the harbor seal's ability to track the wake of an object several seconds after it swam by. In this work, I elucidate the basic fluid mechanisms that seals ...
  • A pendulum inclinometer for use with small deep-submersibles 

    Sharp, Arnold G.; Sullivan, James R. (Woods Hole Oceanographic Institution, 1976-09)
    The authors developed a pendulum inclinometer suitable for use with small deepsubmersibles or surface craft. The instrument uses a relatively short heavy pendulum and a viscous damping system for minimizing the effects ...
  • Performance analysis for lateral-line-inspired sensor arrays 

    Fernandez, Vicente I. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2011-06)
    The lateral line is a critical component of the fish sensory system, found to affect numerous aspects of behavior including maneuvering in complex fluid environments, schooling, prey tracking, and environment mapping. ...
  • Performance analysis of adaptive equalization for coherent acoustic communications in the time-varying ocean environment 

    Preisig, James C. (Acoustical Society of America, 2005-07)
    Equations are derived for analyzing the performance of channel estimate based equalizers. The performance is characterized in terms of the mean squared soft decision error of each equalizer. This error is decomposed into ...
  • Performance bounds on matched-field methods for source localization and estimation of ocean environmental parameters 

    Xu, Wen (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2001-06)
    Matched-field methods concern estimation of source location and/or ocean environmental parameters by exploiting full wave modeling of acoustic waveguide propagation. Typical estimation performance demonstrates two ...
  • Performance of a new generation of acoustic current meters 

    Hogg, Nelson G.; Frye, Daniel E. (American Meteorological Society, 2007-02)
    As part of a program aimed at developing a long-duration, subsurface mooring, known as Ultramoor, several modern acoustic current meters were tested. The instruments with which the authors have the most experience are the ...
  • Performance of the parametric receiving array : effects of misalignment 

    Foote, Kenneth G.; Tjøtta, Jacqueline Naze; Tjøtta, Sigve (Acoustical Society of America, 1987-11)
    The difference frequency sound field from two concentric but misaligned, axisymmetric, planar transducers in a nondissipative and nondispersive medium is developed as a special case of the general theory [Garrett et al., ...
  • A phase-compensated distorted wave Born approximation representation of the bistatic scattering by weakly scattering objects : application to zooplankton 

    Chu, Dezhang; Ye, Zhen (Acoustical Society of America, 1999-10)
    The distorted wave Born approximation (DWBA) method has been successfully used in modeling the acoustic backscattering by weakly scattering zooplankton [Stanton et al., J. Acoust. Soc. Am. 94, 3463–3472 (1993), Wiebe et ...
  • Physical controls on hypoxia in Chesapeake Bay : a numerical modeling study 

    Scully, Malcolm E. (John Wiley & Sons, 2013-03-14)
    A three-dimensional circulation model with a relatively simple dissolved oxygen model is used to examine the role that physical forcing has on controlling hypoxia and anoxia in Chesapeake Bay. The model assumes that the ...
  • Physically constrained maximum likelihood (PCML) mode filtering and its application as a pre-processing method for underwater acoustic communication 

    Papp, Joseph C. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2009-09)
    Mode filtering is most commonly implemented using the sampled mode shape or pseudoinverse algorithms. Buck et al placed these techniques in the context of a broader maximum a posteriori (MAP) framework. However, the MAP ...
  • Physically constrained maximum likelihood mode filtering 

    Papp, Joseph C.; Preisig, James C.; Morozov, Andrey K. (Acoustical Society of America, 2010-04)
    Mode filtering is most commonly implemented using the sampled mode shapes or pseudoinverse algorithms. Buck et al. [J. Acoust. Soc. Am. 103, 1813–1824 (1998)] placed these techniques in the context of a broader maximum a ...
  • Piecewise coherent mode processing of acoustic data recorded on two horizontally separated vertical line arrays 

    Udovydchenkov, Ilya A.; Brown, Michael G.; Duda, Timothy F. (Acoustical Society of America, 2012-05-25)
    Motivated by measurements made in the 2004 Long-Range Ocean Acoustic Propagation Experiment (LOAPEX), the problem of mode processing transient acoustic signals collected on two nearby vertical line arrays is considered. ...
  • Plankton reach new heights in effort to avoid predators 

    Gemmell, Brad J.; Jiang, Houshuo; Strickler, J. Rudi; Buskey, Edward J. (2012-01)
    The marine environment associated with the air-water interface (neuston) provides an important food source to pelagic organisms where subsurface prey is limited. However, studies on predator-prey interactions within this ...
  • A pop-up float recovery system for coastal oceanographic tripods 

    Dunn, Christopher V. R.; Gordon, Allan G. (Woods Hole Oceanographic Institution, 1989-11)
    The recovery package described here was used as the primary retrieval system to recover tripod instrument platforms from a depth of 90 meters. The device uses dual in-line burn wires, one of which is acoustically commanded ...