Technique-Based Exploitation Of Low Grazing Angle SAR Imagery Of Ship Wakes

The pursuit of the understanding of the effect a ship has on water is a field of study that is several hundreds of years old, accelerated during the years of the industrial revolution where the efficiency of a ship’s engine and hull determined the utility of the burgeoning globally important sea lines of communication. The dawn of radar sensing and electronic computation have expanding this field of study still further where new ground is still being broken. This thesis looks to address a niche area of synthetic aperture radar imagery of ship wakes, specifically the imaging geometry utilising a low grazing angle, where significant non-linear effects are often dominant in the environment. The nuances of the synthetic aperture radar processing techniques compounded with the low grazing angle geometry to produce unusual artefacts within the imagery. It is the understanding of these artefacts that is central to this thesis. A sub-aperture synthetic aperture radar technique is applied to real data alongside coarse modelling of a ship and its wake before finally developing a full hydrodynamic model for a ship’s wake from first principles. The model is validated through comparison with previously developed work. The analysis shows that the resultant artefacts are a culmination of individual synthetic aperture radar anomalies and the reaction of the radar energy to the ambient sea surface and spike events

Generation and propagation of ship-borne waves - Solutions from a Boussinesq-type model

Ship-borne waves are of significant interest for the design of port and waterway infrastructure and the maintenance of its surrounding environment. Computation of these nonlinear and dispersive waves has mainly been focusing on their near-field generation as a fluid-body interaction problem. This study presents an approach for the computation of ship waves generated by a moving pressure disturbance with phase-resolving and depth-averaged equations. To support a wide range of applicability, the paper deals with the evolution of the vessel wedge compared to an analytical solution for sub-to supercritical speeds and the assessment of wave patterns from a broad range of pressure term dimensions, including cross-references to findings in other studies. The conducted numerical experiments showcase the typical response of a Boussinesq-type model to a simplified moving pressure disturbance and identify the main factors and criteria for ship-wave propagation in the far-field of a vessel. Finally, a unique field dataset underlines the capability of an extended Boussinesq-type model to compute the propagation of vessel waves over an irregular bathymetry.Hamburg Port Authority (HPA)Japanese Society for the Promotion of Sciences (JSPS)EC/FP7/Marie Curie International Outgoing Fellowshi

Planning for sustainable development of energy infrastructure: fast – fast simulation tool

Energy management has significant impact on planning within local or regional scale. The consequences of the implementation of large-scale renewable energy source involves multifaceted analyses, evaluation of environmental impacts, and the assessment of the scale of limitations or exclusions imposed on potential urbanized structures and arable land. The process of site designation has to acknowledge environmental transformations by inclusion of several key issues, e.g. emissions, hazards for nature and/or inhabitants of urbanized zones, to name the most significant. The parameters of potential development of energy-related infrastructure of facility acquire its local properties – the generic development data require adjustment, which is site specific or area specific. FAST (Fast Simulation Tool) is a simple IT tool aimed at supporting sustainable planning on local or regional level in reference to regional or district scale energy management (among other issues). In its current stage, it is utilized – as a work in progress – in the assessment of wind farm structures located within the area of Poznan agglomeration. This paper discusses the implementation of FAST and its application in two conflicting areas around the agglomeration of Poznan

Acoustic observation, identification, and scattering intensity measurement of cold seep based on bubble resonance

The active “cold seep” is indisputable evidence to identify the existence of submarine gas hydrate. Due to the difference in acoustic properties between cold seep bubbles and surrounding seawater, measuring scattering intensity is a new means to detect active cold seep. Cold seep bubbles are the main cause of acoustic scattering, and the scattering ability is closely related to the frequency of the incident sound wave, the radius of the bubble, and the depth of the bubble. This article introduces a ship-borne cold seep sonar system, which uses the resonance principle of bubbles to measure the scattering intensity at various depths underwater and display it with an intuitive acoustic image. Through the investigation and measurement of the cold seep located in the South China Sea, it is proven that the cold seep sonar system can well identify the submarine cold seep. The measured data are consistent with the theoretical simulation results, confirming that the cold seep bubbles have frequency-selective characteristics for incident sound waves. Compared with other detection methods, it has the characteristics of lossless, fast, and high efficiency.info:eu-repo/semantics/publishedVersio

RRS Charles Darwin Cruise 141, 01 Jun-11 Jul 2002. Satellite Calibration and Interior Physics of the Indian Ocean: SCIPIO

RRS Charles Darwin Cruise 141, SCIPIO (Satellite Calibration and Interior Physics of the Indian Ocean) provided a multidisciplinary survey of the Mascarene Ridge system in the western Indian Ocean. The principal objectives were to (a) study the flow of water masses through the Ridge system, together with their decadal-timescale variability, (b) assess the energy fluxes and mixing arising from internal waves, (c) collect in situ data for the calibration of sea-surface temperature and ocean colour sensors on the ENVISAT satellite, (d) investigate the biogeochemical properties of the water masses, and (e) measure the heat fluxes and winds, and the airflow disturbance around the ship. The survey comprised three sections parallel with the Ridge near 64°, 60° and 57° E, joined by two other sections at 8° and 20°S. The sections comprised CTD, LADCP, and biogeochemistry (nutrients, phytoplankton, zooplankton, biogenic gases, CFC tracers and light levels) stations to full ocean depth, at typical spacings of about 60-80 nm. At several of these the CTD and LADCP were cycled continuously for a semidiurnal tidal cycle to study the internal waves, and the smaller 12-bottle CTD frame was used throughout (usually with 6 bottles) in order to reduce mixing effects from the trailing wake. Underway measurements were made with the shipboard ADCP, TSG, radiosondes, XBTs, and of surface meteorology, skin surface temperature, and zooplankton. The ship's EM12 swath bathymetry system was operated continuously, and used to study certain key areas in detail. In addition, MMP (a cycling CTD) and bottom-mounted ADCP moorings were successfully laid and recovered near 8°S, 60°E, and a first deployment of the ARGODOT turbulence probe was made near 20°S, 57.5°E

Aeronautical Engineering: A special bibliography with indexes, supplement 62

This bibliography lists 306 reports, articles, and other documents introduced into the NASA scientific and technical information system in September 1975

Aeronautical engineering: A special bibliography with indexes, supplement 80

This bibliography lists 277 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1977

Prototype development of low-cost, augmented reality trainer for crew service weapons

A significant emerging threat to coalition forces in littoral regions is from small craft such as jet skis, fast patrol boats, and speedboats. These craft, when armed, are categorized as Fast Inshore Attack Craft (FIAC), and their arsenal can contain an array of weapons to include suicide bombs, crew-served weapons, anti-tank or ship missiles, and torpedoes. While these craft often have crude weapon technologies, they use an asymmetric tactic of large numbers of small, cheap, poorly armed and armored units to overwhelm coalition defenses. Training on crew-served weapons on coalition ships has not advanced to meet this new threat. The current training methods do not satisfactorily train the following skills: Rules of engagement (ROE), marksmanship against highly maneuverable targets, threat prioritization, target designation, field of fire coordination, coordinated arms effects, or watch station to CIC communications. The creation of a prototype Augmented Reality Virtual At Sea Trainer (AR-VAST) shows that emerging augmented reality technologies can overcome limitations of traditional training methods. A fully developed AR-VAST system would be a deployable technology solution that uses in-place weapon systems as trainers in real-world environments with simulated enemy targets. While the AR-VAST architecture can be expanded to allow for training and coordination with multiple weapon operators, phone talkers, and bridge teams for maximum training effectiveness, the current prototype addresses the primary issue of identification and marksmanship.http://archive.org/details/prototypedevelop109453933US Navy (USN) author.Approved for public release; distribution is unlimited

Aeronautical engineering: A continuing bibliography with indexes (supplement 318)

This bibliography lists 217 reports, articles, and other documents introduced into the NASA scientific and technical information system in June 1995. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment, and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

A theoretical/experimental program to develop active optical pollution sensors

Light detection and ranging (LIDAR) technology was applied to the assessment of air quality, and its usefulness was evaluated by actual field tests. Necessary hardware was successfully constructed and operated in the field. Measurements of necessary physical parameters, such as SO2 absorption coefficients were successfully completed and theoretical predictions of differential absorption performance were reported. Plume modeling improvements were proposed. A full scale field test of equipment, data analysis and auxiliary data support was conducted in Maryland during September 1976