Browsing Reprints by Title
Now showing items 419-438 of 548
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Scoring robotic competitions: balancing judging promptness and meaningful performance evaluation
(CMRE, 2019/05)To have a significant and fair competition an adequate scoring system is necessary. Different scoring systems exist, each one directly related to the nature and goals of the competition, e.g. student/educational, focused ... -
Seabed characterization by inversion of parametric sonar data: selection of the cost function
(NATO. SACLANTCEN, 1997)A class of possible cost functions to be used in model-based estimation of bottom parameters from highfrequency backscatter signals is introduced. The cost is based on the properttes of the signal in the wavelettransformed ... -
Seabed sediment characteristics assessed geophysically: results of experiments in the Clyde Sea, Scotland
(NATO. SACLANTCEN, 1997)Within a research programme aimed at developing in situ sediment classification methodologies, it has been demonstrated that with only limited ground truth information, sub-bottom profiler data can be inverted to produce ... -
Seabed survey by VHR multichannel seismics: GEOSIS project
(NATO. SACLANTCEN, 1997)Site surveys prior to the installation of offshore facilities are required to obtain shallow soil structural and geotechnical information. The French project GEOSIS was aimed at improving both geophysical and geotechnical ... -
Secure underwater acoustic networks: current and future research directions
(CMRE, 2019/06)Underwater Acoustic Networks (UANs) are widely used in various applications such as climate change monitoring, pollution control and tracking, tactical surveillance and offshore exploration. However, limited consideration ... -
Security versus defence: dual use from a system requirement perspective
(NURC, 2008/09)The developers of defence technologies in both industry and national laboratories carried their culture for military system development into the evolving security mission, even for systems that are to be used by civilian ... -
Sedimentological acoustics: an attempt to reduce the gap between acoustical modeling and sedimentoloogical survey
(NATO. SACLANTCEN, 1997)A major task in shallow water acoustics is to provide pertinent geoacoustical data. The purpose of the work is to evaluate the state of the art in this field, connecting in situ sedimentological measurement and acoustical ... -
Seismic and hydroacoustic sensing of infrasonic noise in coastal waters
(NATO. SACLANTCEN, 1982/06)Three-component ocean-bottom seismometers with radio links have been deployed in coastal waters to investigate natural and man-made noise at extremely low frequencies. Seismograms from one or up to three sensor stations ... -
Semantic criteria for the assessment of uncertainty handling fusion models
(CMRE, 2019/06)This paper proposes an illustration of the Uncertainty Representation and Reasoning Evaluation Framework (URREF) for the comparison of two classical fusion schemes. We revisit the classical works comparing Bayes' rule and ... -
Sensitivity of ray theory to input data
(NATO. SACLANTCEN, 1971/12)Acoustic propagation problems which are solved using ray theory require certain input data. In particular, the source and receiver locations, sound-velocity field and bottom and surface conditions are required. Frequently, ... -
Sensor-driven glider data processing
(CMRE, 2019/06)Gliders data are an important source of observations for oceanographers, hence harmonization and interoperability among different acquisition systems are key enablers towards efficient data sharing and effective reuse. As ... -
Separability of scattering and reflection parameters in reverberation inversion
(NURC, 2007/11)A premise of reverberation inversion is that one can separate geoacoustic reflection properties from scattering properties since their effects on reverberation are distinguishable. Some doubt has been cast on this premise ... -
Separability of seabed reflection and scattering properties in reverberation inversion
(NURC, 2007/02)Separation of scattering properties (Lambert's mu) from reflection properties (the reflection loss angle derivative alpha) presents difficulties in the geoacoustic inversion of long range reverberation in isovelocity ... -
Separation of measured noise coherence matrix into Toeplitz and Hankel parts
(CMRE, 2017/08)The cross-spectral density of ocean ambient noise is usually estimated from the product of the complex hydrophone signals, each of which already corresponds to the summed responses of sources from all angles. The true ... -
Shallow water propagation incorporating both bubble plumes and sea-surface roughness
(NATO. SACLANTCEN, 1997)The effect of including a range dependent bubble layer and a suitable sea surface spectrum in modeling shallow water propagation is analyzed. Propagation is simulated through a hrghly accurate model based on a modified PE ... -
Shallow water reverberation modeling using an autoregressive range-scattering function approach
(NATO. SACLANTCEN, 1997)The primary limitation on system performance for active sonars is reverberation - the reradiation of acoustic energy back to the receiver from inhomogeneities in the physical properties of the medium and its boundaries. A ... -
Shallow water synthetic aperture sonar: an enabling technology for NATO MCM forces
(NURC, 2007/10)The change in military focus from Cold War doctrine to expeditionary operations in shallower littoral water and the heightened terrorist threat to ports and their approaches, have put increased emphasis on countering ... -
Shallow-water ASW sonar design
(NATO. SACLANTCEN, 1993/08) -
Shallow-water coherence of broadband signals
(NATO. SACLANTCEN, 1997)The frequency-dependent spatial and temporal variabilities of sound propagation in coastal regions is investigated by ezperiment and numerical simulations. Experimental observations show that temporal coherence of the ... -
Shallow-water seafloor characterization for high-frequency multibeam echosounder: image segmentation using angular backscatter
(NATO. SACLANTCEN, 1997)Sonar images from multibeam echosounders are submitted to various degradations, partly due to the sensor itself: Signal artefacts and corresponding corrections are presented, both for signal processing and for array ...