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Increasing demand on marine resources is driving the need to more efficiently and effectively enable multiple uses of marine space by different sectors and interests. This raises governance challenges particularly because traditional management practice primarily has been sector and issue-specific. Conceptually, marine spatial planning (MSP) provides an integrated framework that could be a viable...
Acoustic communication is the most common technique to communicate with an autonomous underwater vehicle (AUV) during its mission. Furthermore, this communication channel is often used for ranging, to support the navigation of the vehicle and localize it in world coordinates, whereas the vehicles dead reckoning only gives a relative position to a starting point. Due to the severe multipath propagation...
In most of the current operational autonomous underwater vehicles (AUVs), a survey mission is generally composed of two main stages. The first one conducts an exhaustive coverage over an area of interest, while gathering data of the sea bottom. Then, and after processing the collected data, a second mission is programmed to obtain more detailed information of potential targets, and to cover the gaps...
Photocatalytic technology using TiO2 is one of the emerging approaches for water treatment, especially as a final step to remove complex organics such as pesticides, hormones or humic acids. Titanium dioxide (TiO2) is a semiconductor material with strong UV absorption band and exhibits strong photocatalytic activity. The photocatalytic activity of TiO2 powders have been extensively studied, using...
The article is about the development of a sealing system for pressure housings made of ultra-high performance concrete (UHPC), which has been developed within the Helmholtz Alliance “ROBEX” (robotic exploration of extreme environments) [1]. Several kinds of sealing systems according to the material properties of concrete have been designed so far and the amount of aluminum or titanium needed has been...
Improved understanding of the dynamics of tidal currents and ocean waves and the loads they impose on tidal turbines is a prerequisite for an economically viable tidal turbine industry. The dynamic environment effects machine design and reliability, has consequences on operations and maintenance and ultimately energy conversion rate. Over the course of a recently completed five year international...
Marine biodiversity is increasingly affected by human activities such as climate change, habitat destruction and fishing. In this context a key challenge for marine biologists is to be able to monitor biodiversity at large scale and high temporal frequency. However, underwater observations of marine biodiversity based on free or SCUBA diving are practically limited in terms of maximal depth and duration...
In this paper, preliminarily a proposal for design guidelines for a “good” design of wave energy converter is presented and successively a small scale prototype of a wave energy converter including the buoyant electrical generator, the power electronics equipment and a sea water electrolyzer is designed on the basis of these guidelines and presented.
Long period fiber gratings (LPFGs) were over coated with iron (Fe) and subjected to oxidation in air and in solutions of water containing different sodium chloride (NaCl) concentrations. The formation of iron oxides and hydroxides was monitored in real time by following the features of the gratings attenuation band. Preliminary results show that Fe coated LPFGs can be used as sensors for early warning...
The paper presents the first simulative results and algorithmic developments of the task-priority based control applied to a distributed sampling network in an area coverage or adaptive sampling mission scenario. The proposed approach allowing the fulfilment of a chain of tasks with decreasing priority each of which directly related to both operability and safety aspects of the entire mission. The...
The EU NeXOS project engineering outputs show that once successful and reaching TRL > 7 [], the sensor cost is highly dependent on the mechanical parts, then, the production cost only diminishes with very large production. And, the loss of equipment is in many cases induced by mechanical failures. In the EU NeXOS project, some design and test principles have been promoted in order to minimize at...
A modular open source real-time simulation environment for linear model predictive control (LMPC) of line following at a constant depth is developed for underactuated marine vehicles. Two-stage tuning method of MPC's parameters is implemented as an extension of this simulator. MPC is used for high level control, i.e. setting the yaw rate reference, which is then tracked by the low level PID controllers...
Heavy metal ion pollution emerges as a potential threat to humankind and the ecosystem due to their increased spreading into the environment. Detection of highly toxic heavy metal ions requires rapid, simple, sensitive and selective detection methods in water environments. Optical fibre sensors facilitate the remote, continuous and in-situ detection due to their inherent properties. Herein, we report...
We demonstrate an attempt on seismic oceanography (SO) study by using seismic “noise” for imaging Kuroshio Current in the offshore Taiwan. The Kuroshio around Taiwan has moderate seasonal variation but with complicated spatial distribution. Multi-Channel Seismic (MCS) reflection profiling has the advantages for detecting any impedance changes associated with physical processes (temperature, salinity,...
Measuring the background noise in the ocean can be challenging. Prior approaches to using measured data to estimate the background noise field have relied on collecting data during a series of tow vessel maneuvers. This paper presents an alternate approach to estimating the noise field that does not rely on tow vessel maneuvers to collect the necessary data. This approach fuses data from a traditional...
Most Autonomous Underwater Vehicles (AUVs) mount an Acoustic Doppler Current Profilers (ADCP). Data from this sensor are rarely used in scientific studies due to the complexity of its processing and the lack of validation. Aside of that, AUV operators lack a set of guidelines regarding the optimal navigation modes and AUV-borne ADCP configurations to obtain the most accurate data possible. This study...
The optimal detector based on matched-field processing with a large-aperture vertical linear array (VLA) suffers from the so called “snapshot deficient problem”, which leads to an inaccurate estimate of the noise covariance matrix and hence a degraded detection performance. In this paper, to improve the detection performance with deficient snapshots, a two-step sub-array detector (SAD) is proposed...
In this study, SAR oil spill observation is investigated for different polarizations, incidence angles and wind conditions. The dataset is composed by a time-series of 42 TerraSAR-X dualpol SAR images acquired between July 2011 and April 2016. The incidence angle, wind speed and polarization dependency for oil spill observation is shown for the first time using a large time-series of the same oil...
In this study, TanDEM-X full-polarimetrlc bistatic and monostatic imagery are exploited for maritime applications purposes. The Mueller matrix and the phase difference between co-polarized channels (CPD) are exploited to deal with both the monostatic and the bistatic scenes. Subtle differences are found between the Mueller matrix collected in bistatic/monostatic mode; while similar performance is...
The Teledyne Optech CZMIL (Coastal Zone Mapping and Imaging Lidar) is an airborne system primarily designed for topographic and bathymetric mapping. The combination of a scanning lidar, RGB camera system, and optional ITRES Co. hyperspectral instrument, in conjunction with the Optech HydroFusion software suite within a data fusion paradigm, makes CZMIL an integrated lidar-imagery system for the highly...
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