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This paper investigates a fundamental networking problem in underwater sensor networks: robust and energy-efficient routing. We present an adaptive location-based routing protocol, called hop-by-hop vector-based forwarding (HH-VBF). It uses the notion of a "routing vector" (a vector from the source to the sink) acting as the axis of the "routing pipe", similar to the vector based...
Confidence in naval operations that search for mine-like objects (mine-hunting) is dependent on knowledge of the operational environment. Historic information in some areas may misrepresent the environmental picture due to sparse measurement or data perishability. As a result, operations in some areas may require real-time environmental measurements to refresh the data sources. This information can...
Maneuvering and seakeeping are two very important naval architecture research areas. There are several methods to determine a vessel's behavior, but most of them are time-consuming, apply linear techniques or introduce several simplifications. This paper proposes to apply feed-forward neural networks to predict maneuvering behavior in the design phase or following changes on a new design. The feed-forward...
In this article, based on Blind Source Separation (BSS) often used in the cocktail party problem, a new online BSS algorithm SIRP-NG is developed. Utilizing on the Information Maximization principle and the Infomax algorithm, it uses Spherically Invariant Random Process (SIRP) to model the univariate band-limited speech signals used in telephone and underwater wireless communications. The Meijer G...
This paper proposes an artificial intelligence based framework for integrated fault detection and diagnosis to support supervision and decision making applicable to subsea control systems. Instrumentation, electrical, electronic, hydraulic and communication subsystems are considered. This approach may contribute to minimizing well shut-down and production losses due to unexpected faults on any subsea...
Planktonic animals occur from the surface to the sea bottom and they are exposed to hydrostatic pressure throughout their lifetime. A hydrostatic pressure apparatus integrating ideas of past apparatuses was developed to investigate effects of hydrostatic pressure on marine zooplankton. The pressure apparatus system is composed of a peristaltic pump, a pressure chamber, a specimen holder which is placed...
This paper presents a novel design of carrier interferometry (CI) spreading codes by using inverse fast Fourier transform (IFFT) instead of linear transformation. Pulse shaping method in frequency domain is used to generate different carrier interferometry orthogonal frequency division multiplexing (CI/OFDM) signals. Peak-to-average power ratio (PAPR) and BER performance have been compared between...
Autonomous underwater vehicles (AUV's) provide an important tool for collecting detailed scientific information from the oceans depths. The hull resistance of an AUV is an important factor in determining the powering requirements and range of the vehicle. This paper discusses the use of computational fluid dynamics (CFD) to determine the hull resistance of three existing AUV's, of differing shape...
We introduce an iterative maximum aposteriori probability (MAP) method for combining meteorological model output with synthetic aperture radar for offshore wind field estimation. The MAP approach is demonstrated for 40 ENVISAT ASAR scenes collected for 2004-2006 over the UK Irish Sea. The CMOD4 and CMOD5 geophysical model functions are compared and retrievals using MAP and a simpler directon based...
Ships of opportunity such as scheduled ferry services offer the potential for cost effective oceanographic measurements to be undertaken with a high temporal resolution. This provides a convenient mechanism to measure near surface water properties as a series of transects along regularly scheduled routes. There are many potential applications for this kind of system which can effectively compliment...
Conventionally, underwater communications are achieved using acoustic method. However, it has its limitation. Recently, there are interests to find new methods for high bit rate, short range underwater communications. In the past, electric current method was shown to be useful for long range analog underwater communication. This paper shows that it is capable of delivering much higher bit rate digital...
The inexhaustible wave energy resource is at the basis of the increasing research on wave energy exploitation. Till now the resource is studied in detail for regions with a high wave energy density. As the problems to guarantee the survivability of wave energy converters (WECs) in a severe and energetic wave climate are not solved yet, the possibilities of wave power conversion in a less aggressive...
We report the design, prototype construction and initial testing of a small minibuoy that is aimed at use in a coordinated, wireless networked array of buoys for ocean surface sensing, both above and below the surface. This vehicle is designed to fill the gap between larger ocean surface vessels and/or moored buoys and subsurface gliders. The size and cost is low enough that these versatile sensor...
This paper describes the EU-funded development of the SIMORC Internet service providing an index metadatabase and a database of Metocean data sets, that are collected by major oil & gas companies worldwide. The Service is set-up to facilitate the wider use of these data sets by scientific users and private industry. Important aspects are e.g. a standard quality control and harmonisation in formats...
The magnitude of the UK tidal current resource has been examined by a number of different reports, each attempting to define a figure which is representative of the commercially exploitable energy in the flow. Recent work suggests that the exploitable resource is of the order of one fifth the size of the raw flux passing through a channel. It is not possible to develop an indicative value of the exploitable...
An important issue in the preliminary design of autonomous underwater vehicles (AUVs) is the selection of the optimal dimensions for the vehicle (sizing). These dimensions are dependent on the characteristics of the mission, the operating environment and the chosen technology. This paper presents a computer-based design-tool, which integrates all major design parameters to allow an efficient and rapid...
The registration and 3D mosaicing of range images presents an interesting challenge for the underwater domain. This work attempts to lay out some of the issues involved in generating large 3D reconstructions of the benthos from two distinct views gathered from an AUV. Specifically, we address using 3D feature correspondence to estimate a Euclidean transformation between views and then refine that...
The Simrad MS70 is a broadband scientific multibeam sonar with nominal operating frequency band 70-120 kHz. Two spheres have been specified for use in calibrating this sonar, with piecewise coverage of the band and target strength values in the range from -35 to -30 dB. The sphere material is tungsten carbide with 6% cobalt binder; the diameters are 75 and 84 mm. The same spheres can also be used...
Massachusetts Maritime Academy (MMA) conducted a study to evaluate the potential impact of the MMA wind turbine (Vestas V47-660 kW) on birds, including common terns (Sterna hirundo), which are protected at the state level, and roseate (S. dougalii) terns, which are protected at the federal level. We found that common terns were relatively abundant on the water adjacent to the wind turbine, especially...
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