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In this paper we propose the use of Wave Energy Converter and saline water to produce hydrogen. Two different scheme and technology are proposed. The objective of this research is to design an electrolyzing system capable of utilizing sea. In particular, we present the results obtained by two different prototype of electrolyzer: one with steel electrodes and the second with titanium electrodes. Further...
Management of oceanographic data is particularly challenging due to the variety of protocols for data collection and analysis and the vast range of oceanographic variables studied. This paper describes the end-to-end cyber infrastructure developed to support stakeholders in the ocean science community throughout the data life cycle: from immediately after data collection through numerical analysis...
In the application described here, an autonomous marine vehicle (AMV) is equipped with a 3D seismic sensor array (3DSA). The 3DSA consists of 15 hydrophones mounted on cubic frame of about 1 m in size. Various field tests and commercial projects have been conducted using autonomous vehicles as platforms, each towing a 3DSA. Often, these have been deployed during ongoing traditional seismic surveys,...
Eigenvalue distributions of multi-channel radar systems can be used to predict the achievable detection performance for moving target indication. For sea data they additionally inform about the present sea state. In this paper airborne experiments with the commercially available radar system SlimSAR were performed to analyze the eigenvalue distributions of real and simulated data of land, sea and...
Studying fish recognition has important realistic and theoretical significance to aquaculture and marine biology. Fish recognition is challenging problem because of distortion, overlap and occlusion of digital images. Previous researchers have done a lot of work on fish recognition, but the classification accuracy may be not high enough. Classification and recognition methods based on convolutional...
A series of experiments were conducted to investigate the effect of ventilation on supercavity around a supercavitating vehicle during water-entry. An elaborate facility equipped with a complete set of measurement and control system was built, and the supercavitating vehicle was typically set to be launched at 20 degrees angle with a speed of 70 m / s. Firstly, the experiment was carried out to investigate...
An enhanced normalized least mean squares (NLMS) adaptive equalization scheme is proposed for single-carrier underwater acoustic (UWA) communications. The enhancement is achieved via two techniques: the sparse adaptation (SA) technique and the data reuse (DR) technique. The SA technique speeds up the convergence and improves the performance of the adaptive equalization, by taking advantage of the...
In this paper, a novel approach to high resolution underwater acoustic imaging is proposed for limited aperture. The proposed imaging approach is based on cross-correlation and high resolution is achieved by using ultra-wideband (UWB) signals in combination with cross-correlation processing. The idea of the proposed imaging approach is that cross-correlation of a pair of the received UWB signals can...
In this paper, the natural supercavitys are studied both experimentally and numerically. A series of supercavitating vehicle water-entry test are carried out at different speeds, where it is found that the minimum pressure in the cavity gradually reduced with the increase of water-entry speed. The cause for the evolution progress of natural supercavitation is difficult to get from the experiment,...
This paper proposed two methods to analyze marine riser, which is Finite Element Method (FEM) and Extended Kalman Filter (EKF) method. Due to environmental disturbances and ship motion, the occurrence of riser's large deflections will bring fatigue problems and propagation cracks, which will lead to environmental disasters. Compare the two methods to derive structural parameters of riser, such as...
Noncoherent underwater acoustic communication faces the problems of the high requirement of the signal noise ratio per bit and the inconsistency of performances between the simulation and the experiment. Noncoherent channel capacity based on composite fading model is studied, and a novel scheme of code and modulation approaching the noncoherent capacity is present. In the scheme, multi-tone frequency...
The development of revolutionary tools such as AUVs and other unmanned vehicles has offered oceanographers a chance to explore areas that are not easily accessible and address questions that have yet to be answered. The ability of unmanned vehicles to reach these under-sampled parts of the ocean is motivating researchers to install, equip, and attach as many sensors as possible to obtain measurements...
FrFT is a new tool which has a dominant advantage to detect LFM-signal. However, under the multipath environment, the LFM signal is distortion on account of the non-correlation superimposition of the multipath component, which results in performance degradation of the detector based on FrFT. In this paper, a combination of time-reversal focusing and Fractional Fourier Transform algorithm is proposed...
Developing a new sonar for side-scan imaging can be a complicated and expensive proposition. Sonar models and simulations can be used to alleviate some of the expense and time required for development by providing some early simulated imagery of proposed designs. This paper describes a modeling approach where inverse imaging techniques are applied in order to generate simulated stave-level sonar data...
Unmanned or manned underwater vehicles are often designed in cylindrical shapes which have desirable properties for withstanding the pressures that can be experienced in undersea environments. However, cylindrical designs are not required for non-pressurized enclosures. Non-cylindrical designs may provide benefits to developers including allowing a wider variety of materials for construction, greater...
Underwater imaging has become a staple tool used by scientists exploring the deep ocean. Advanced camera systems are able to combine quantitative measurements from in-situ sensors with qualitative imaging to provide high fidelity multi-dimensional datasets which can be used to support a wide range of science questions. This includes benthic characterization and mapping, identification of biota and...
This paper presents an optimal waveform design method using Multi-Tone Sinusoidal Frequency Modulation (MTSFM). The MTSFM waveform's modulation function is represented using a Fourier series expansion. This representation results in a constant amplitude waveform with a continuous modulation function whose spectrum, Auto-Correlation Function, and Ambiguity Function shapes can be modified by adapting...
The knowledge of water temperature profiles of the upper-ocean mixed layer provides valuable input to climate studies, weather forecasts and oceanography in general. A remote-sensing lidar is an attractive method for real-time measurements of these data. The principle idea of our approach is a lidar using the time-of-flight information to measure the depth and relying on spontaneous Brillouin scattering...
This paper focus on the use of unmanned aerial vehicle teams for performing cooperative perception using Data Distribution Service (DDS) Network. We develop a DDS framework to manage the incoming and out bounding network traffic of multiple types of data that is exchanged inside the UAV network. Experimental results both in laboratory and in actual flight are presented to help characterize the proposed...
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