Passive Acoustic Array Harbor Security Applications

2011 ◽  
Vol 45 (3) ◽  
pp. 103-110 ◽  
Author(s):  
John Gebbie ◽  
Martin Siderius ◽  
John S. Allen
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Water Environment ◽  
Open Circuit ◽  
Security Applications ◽  
Vertical Arrays ◽  
Detection And Tracking ◽  
Acoustic Methods ◽  
Remote Environment ◽  
Acoustic Array ◽  
Passive Acoustic

AbstractHarbor security and protection of maritime assets are issues of increasing concern. Outstanding research questions exist in terms of the optimal protection methodology needed for the wide variety of surface and submerged threats and diverse geographical locations. Economic costs and environmental concerns are also significant overriding issues. Acoustic methods have the advantage of being amenable to tracking and detecting targets both above and below the ocean surface. Moreover, passive acoustic methods are nonintrusive and capable of covering extensive ranges. Acoustic arrays offer significant advantages in terms of gain and signal processing capabilities over discrete, single hydrophones. We investigate the use of horizontal and vertical arrays for the detection and tracking of a remote environment monitoring system (REMUS) autonomous underwater vehicle as well as open-circuit divers in a noisy, shallow water environment. Using conventional beamforming techniques, we obtain positive preliminary results for detection and tracking, which highlight the overall merits of an acoustic array implementation.

Hawaii Experimental Acoustics Range for Shallow Water Applications

2011 ◽  
Vol 45 (3) ◽  
pp. 69-76 ◽  
Author(s):  
Tom Fedenczuk ◽  
Eva-Marie Nosal
Keyword(s):  
Shallow Water ◽  
Water Environment ◽  
Shallow Water Acoustics ◽  
Central Node ◽  
Long Baseline ◽  
Wide Range ◽  
Shallow Water Environment ◽  
Near Shore ◽  
Monitoring And Surveillance ◽  
Passive Acoustic

AbstractShallow water acoustics provide a means for monitoring and surveillance of near-shore environments. This paper describes the current and future capabilities of the low- to high-frequency Hawaii Experimental Acoustics Range (HEAR) that was designed to facilitate a wide range of different shallow water acoustics experiments and allow researchers from various institutions to test various array components and configurations. HEAR is a portable facility that consists of multiple hydrophones (12‐16) cabled independently to a common central node. The design allows for variable array configurations and deployments in three modes: experimental (off boats and piers), autonomous, and cabled. An application of HEAR is illustrated by the results from a deployment at Makai Research Pier, Oahu, Hawaii. In this deployment, HEAR was configured as a long-baseline range of two volumetric subarrays to study passive acoustic tracking capabilities in a shallow water environment.

Fish Bioacoustics and Behavior: Passive Acoustic Detection and the Application of a Closed-Circuit Rebreather for Field Study

2001 ◽  
Vol 35 (2) ◽  
pp. 19-28 ◽  
Author(s):  
Phillip S. Lobel
Keyword(s):  
Behavioral Ecology ◽  
Daily Basis ◽  
Open Circuit ◽  
Acoustic Detection ◽  
Ecological Processes ◽  
Detection Technology ◽  
Scientific Goal ◽  
Species Specific ◽  
Passive Acoustic ◽  
And Behavior

The simple thesis of this paper is that using rebreathers to study fish behavioral ecology, especially bioacoustics, is well worth the expense and additional training required. The scientific goal of my bioacoustic research is to determine which fishes produce species-specific sound patterns exclusively with explicit acts of courtship and mating. This provides scientific insight into evolutionary and ecological processes and also provides data necessary to develop the passive acoustic detection technology for monitoring fish reproduction. When used on a daily basis, rebreathers, in my experience, are economical and as practical as open circuit scuba. This is based both on the costs of diving as well as the efficiency of gathering useful data. The use of open circuit SCUBA while conducting acoustic recordings results in a loss of at least 40% of the data due to the bubble noise from a divers breathing. Rebreathers also provide extended bottom time, especially in shallow water, which enhances a diver's ability to observe fish and gather acoustic-behavioral data.

Thin mesoporous polyaniline films manifesting a water-promoted photovoltaic effect

2013 ◽  
Vol 67 (8) ◽  
Author(s):  
Natalia Gospodinova ◽  
Elena Tomšík ◽  
Julia Romanova
Keyword(s):  
Indium Tin Oxide ◽  
Theoretical Calculations ◽  
Photovoltaic Effect ◽  
Water Environment ◽  
Solvent Polarity ◽  
Open Circuit ◽  
Interpenetrating Network ◽  
Hydrated Ions ◽  
Polyaniline Films ◽  
Oxide Anode

AbstractPhotovoltaic cells composed of thin mesoporous polyaniline films sandwiched between an indium-tin oxide anode and aluminium cathode have been fabricated. The cells show an increase in the photo-generated open-circuit voltage (V oc) from 0.2 V to 0.6 V and stable-in-time V oc generation following the addition of water containing highly hydrated ions, e.g. tap water.We explain the waterpromoted photo-voltaic effect by the polarity of the water environment. Theoretical calculations show that increasing the solvent polarity increases the energy of the electronic transition related to the measured V oc. The stable-in-time V oc generation could be explained by the increase in the lifetime of the excitons as well as by their more efficient dissociation in the interpenetrating network of polyaniline and water. The penetration of water into the mesoporous polyaniline films is promoted by the presence of highly hydrated ions.

scholarly journals Passive acoustic methods for tracking the 3D movements of small cetaceans around marine structures

PLoS ONE ◽  
2020 ◽  
Vol 15 (5) ◽  
pp. e0229058 ◽  
Author(s):  
Douglas Gillespie ◽  
Laura Palmer ◽  
Jamie Macaulay ◽  
Carol Sparling ◽  
Gordon Hastie
Keyword(s):  
Marine Structures ◽  
Acoustic Methods ◽  
Passive Acoustic

scholarly journals Moving target detection and tracking using passive acoustic radar

2016 ◽  
Author(s):  
Felix J. Yanovsky ◽  
Rustem B. Sinitsyn ◽  
Yevhen Chervoniak ◽  
Vitaliy Makarenko ◽  
Vadim Tokarev ◽  
...  
Keyword(s):  
Target Detection ◽  
Moving Target ◽  
Moving Target Detection ◽  
Detection And Tracking ◽  
Passive Acoustic
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