scholarly journals Three-dimensional multiple-source focalization in an uncertain ocean environment

2013 ◽  
Vol 134 (5) ◽  
pp. EL426-EL431 ◽  
Author(s):  
Dag Tollefsen ◽  
Stan E. Dosso
Keyword(s):  
Three Dimensional ◽  
Multiple Source ◽  
Ocean Environment

scholarly journals An Energy Efficient Routing Approach for IoT Enabled Underwater WSNs in Smart Cities

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4116
Author(s):  
Nighat Usman ◽  
Omar Alfandi ◽  
Saeeda Usman ◽  
Asad Masood Khattak ◽  
Muhammad Awais ◽  
...  
Keyword(s):  
Energy Efficient ◽  
Water Surface ◽  
Power Transmission ◽  
Smart Cities ◽  
Cluster Head ◽  
Three Dimensional ◽  
Energy Efficient Routing ◽  
Underwater Environment ◽  
Ocean Environment ◽  
Smart Technologies

Nowadays, there is a growing trend in smart cities. Therefore, Terrestrial and Internet of Things (IoT) enabled Underwater Wireless Sensor Networks (TWSNs and IoT-UWSNs) are mostly used for observing and communicating via smart technologies. For the sake of collecting the desired information from the underwater environment, multiple acoustic sensors are deployed with limited resources, such as memory, battery, processing power, transmission range, etc. The replacement of resources for a particular node is not feasible due to the harsh underwater environment. Thus, the resources held by the node needs to be used efficiently to improve the lifetime of a network. In this paper, to support smart city vision, a terrestrial based “Away Cluster Head with Adaptive Clustering Habit” (ACH) 2 is examined in the specified three dimensional (3-D) region inside the water. Three different cases are considered, which are: single sink at the water surface, multiple sinks at water surface,, and sinks at both water surface and inside water. “Underwater (ACH) 2 ” (U-(ACH) 2 ) is evaluated in each case. We have used depth in our proposed U-(ACH) 2 to examine the performance of (ACH) 2 in the ocean environment. Moreover, a comparative analysis is performed with state of the art routing protocols, including: Depth-based Routing (DBR) and Energy Efficient Depth-based Routing (EEDBR) protocol. Among all of the scenarios followed by case 1 and case 3, the number of packets sent and received at sink node are maximum using DEEC-(ACH) 2 protocol. The packets drop ratio using TEEN-(ACH) 2 protocol is less when compared to other algorithms in all scenarios. Whereas, for dead nodes DEEC-(ACH) 2 , LEACH-(ACH) 2 , and SEP-(ACH) 2 protocols’ performance is different for every considered scenario. The simulation results shows that the proposed protocols outperform the existing ones.

ACOUSTIC THREE-DIMENSIONAL EFFECTS AROUND THE TAIWAN STRAIT: COMPUTATIONAL RESULTS

1999 ◽  
Vol 07 (01) ◽  
pp. 15-26 ◽  
Author(s):  
CHI-FANG CHEN ◽  
JANG-JIA LIN ◽  
DING LEE
Keyword(s):  
Field Data ◽  
Bottom Topography ◽  
Three Dimensional ◽  
Propagation Model ◽  
Computational Results ◽  
Submarine Canyons ◽  
Offshore Area ◽  
Ocean Environment ◽  
The Taiwan Strait ◽  
Good Agreement

A set of experiments were performed in the offshore area off the coasts of Taiwan and three-dimensional (3-D) measurements recorded. The 3-D effect on underwater propagation due to azimuthal variation of bottom topography is studied for the offshore regions southwest of Taiwan, where submarine canyons exist. A 3-D acoustic propagation model, FOR3D, is used to detect the 3-D effect. Computational results show that the 3-D effect is more prominent along the axis of the canyon than across it. Calculations show a very good agreement with field data, which indicate that the 3-D effect exists in this realistic ocean environment.

A Three-Dimensional Geometrically Nonlinear Analysis of Pipelaying in an Ocean Environment

1981 ◽  
Vol 103 (2) ◽  
pp. 201-205
Author(s):  
S. Odorizzi ◽  
B. A. Schrefler
Keyword(s):  
Hydrostatic Pressure ◽  
Nonlinear Analysis ◽  
Dimensional Analysis ◽  
Three Dimensional ◽  
Bending Stiffness ◽  
Ocean Floor ◽  
Geometrically Nonlinear ◽  
External Hydrostatic Pressure ◽  
Geometrically Nonlinear Analysis ◽  
Ocean Environment

A three-dimensional analysis for pipelines suspended between the ocean floor and a laying barge or a stinger is presented. The analysis performed is capable of handling not only variations in bending stiffness, weight and buoyancy, crosscurrents and lateral bay drift, but also the effects of external hydrostatic pressure and buckling of the pipes. For this purpose a total Lagrangian geometrically nonlinear analysis in space. Examples are given which demonstrate the versatility of the analysis proposed.

Three-Dimensional Ocean Wave Simulation Based on Directional Spectrum

2011 ◽  
Vol 94-96 ◽  
pp. 2074-2079 ◽  
Author(s):  
Qiu Ying Guo ◽  
Zun Yi Xu ◽  
Ying Jun Sun
Keyword(s):  
Navigation System ◽  
Three Dimensional ◽  
Ocean Waves ◽  
Directional Spectrum ◽  
Wind Speeds ◽  
Simulation Speed ◽  
Spreading Function ◽  
Interaction Simulation ◽  
Ocean Environment ◽  
Key Techniques

Simulating real virtual ocean environment is necessary for the research of interaction simulation of underwater gravity aided inertial navigation system. One of the key techniques of realizing virtual ocean environment is modeling and simulating three-dimensional ocean waves. Numerical simulation of three-dimensional ocean waves in the case of different wind speeds is realized using MATLAB based on directional spectrum composed of Pierson-Moscowitz frequency spectrum and directional spreading function. Experiments show that the simulation speed is fast and the simulation results are vivid if suitable simulation frequency band, interval of wave frequency and interval of direction angle are selected. The simulation can provide some technological supports for interaction simulation of gravity aided navigation system for underwater vehicles.

Panoramic Reconstruction of the Sea Floor Environment, Using Underwater Photography, Direct Observations, and Field Sketches

2006 ◽  
Vol 40 (2) ◽  
pp. 52-57
Author(s):  
Andres Pruna ◽  
Robert L. Mairs
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Submarine Cable ◽  
Panoramic View ◽  
Sea Floor ◽  
Photographic Technique ◽  
Direct Observations ◽  
Underwater Photography ◽  
Graphic Illustration ◽  
Ocean Environment

Graphic illustration by a scientifically trained artist provides a panoramic view of the sea floor unobtainable directly by photography. Detailed photographs, direct observations, and field sketches are combined to produce a photographically documented hypsographic reconstruction of the sea floor. Dry submersible or diver traverses show only a sequence of closeup photographs because of the visibility limitations presented by the ocean environment. At present the large scale aspects of the topography are best developed from direct observations. The underwater photographs arranged in traverse sequence serve to refresh the memory and provide topographic, geologic, and biologic detail. The resulting detailed illustration gives a three dimensional composite panorama of the sea floor. This combined artist-photographic technique has been applied to: submarine cable routing, habitat emplacement, and geological and biological reconnaissance.

Three‐dimensional terrain modeling with multiple‐source illumination

2019 ◽  
Vol 23 (5) ◽  
pp. 937-959 ◽  
Author(s):  
I. V. Florinsky ◽  
S. V. Filippov
Keyword(s):  
Three Dimensional ◽  
Multiple Source ◽  
Terrain Modeling ◽  
Source Illumination

On Irregular, Nonlinear Waves in a Spread Sea

1997 ◽  
Vol 119 (1) ◽  
pp. 37-41 ◽  
Author(s):  
P. Jonathan ◽  
P. H. Taylor
Keyword(s):  
Nonlinear Waves ◽  
Three Dimensional ◽  
Nonlinear Effects ◽  
Detailed Comparison ◽  
Offshore Structures ◽  
Sea Surface ◽  
Linear Wave ◽  
Ocean Environment ◽  
Wave Nonlinearity ◽  
Good Agreement

Optimal design and reassessment of offshore structures requires a good understanding of the ocean environment. The motion of the sea surface can be viewed as a three-dimensional, nonlinear stochastic process in time. In order to characterize the wave environment adequately, we need to model its random, nonlinear, and spread nature. In this paper, we address: • the expected shape of a wave near a crest or trough, • the expected shape of the ocean surface at one point, given a crest at a different point, • an efficient method to incorporate nonlinear effects within linear wave simulations, • the magnitude of wave nonlinearity as a function of wave amplitude. Detailed comparison of theory and full-scale offshore measurements at the Shell Expro Tern platform show good agreement.

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