نتایج جستجو برای: underwater ambient noise

تعداد نتایج: 256563  

2013
Megan F. McKenna Sean M. Wiggins John A. Hildebrand

Low-frequency ocean ambient noise is dominated by noise from commercial ships, yet understanding how individual ships contribute deserves further investigation. This study develops and evaluates statistical models of container ship noise in relation to design characteristics, operational conditions, and oceanographic settings. Five-hundred ship passages and nineteen covariates were used to buil...

Journal: :Ad Hoc Networks 2015
Dustin Torres Jonathan Friedman Thomas Schmid Mani B. Srivastava Youngtae Noh Mario Gerla

As underwater communications adopt acoustics as the primary modality, we are confronting several unique challenges such as highly limited bandwidth, severe fading, and long propagation delay. To cope with these, many MAC protocols and PHY layer techniques have been proposed. In this paper, we present a research platform that allows developers to easily implement and compare their protocols in a...

Journal: :Conservation biology : the journal of the Society for Conservation Biology 2012
Leila T Hatch Christopher W Clark Sofie M Van Parijs Adam S Frankel Dimitri W Ponirakis

The effects of chronic exposure to increasing levels of human-induced underwater noise on marine animal populations reliant on sound for communication are poorly understood. We sought to further develop methods of quantifying the effects of communication masking associated with human-induced sound on contact-calling North Atlantic right whales (Eubalaena glacialis) in an ecologically relevant a...

Journal: :The Journal of experimental biology 2007
Raquel O Vasconcelos M Clara P Amorim Friedrich Ladich

Underwater noise pollution is an increasing environmental problem which might affect communication, behaviour, fitness and consequently species' survival. The most common anthropogenic noises in aquatic habitats derive from shipping. In the present study we investigated the implications of noise pollution from a ship on the sound detectability, namely of conspecific vocalizations in the Lusitan...

2012
José S. G. Panaro Fábio R. B. Lopes Leonardo M. Barreira Fidel E. Souza

This article presents an empirical model for the noise of the acoustic underwater channel in shallow water from the analysis of field data measurements. A probability density function for the noise amplitude distribution is proposed and the associated likelihood functions are derived. As a result, an expression to the probability of symbol error for binary signaling is presented for the channel...

Journal: :Optics express 2016
Tasnim Hamza Mohammad-Ali Khalighi Salah Bourennane Pierre Léon Jan Opderbecke

We investigate the effect of environmental noise, caused by solar radiations under water, on the performance of underwater wireless optical communication (UWOC) systems. Presenting an analytical and generic model for this noise, we examine its impact on the link performance in terms of the bit error rate (BER). This study is conducted for different photo-detector types in the aim of highlightin...

2013
Anuj Sehgal Daniel Cernea Andreas Birk

The maximum potential for underwater exploration rests within the use of multiple Autonomous Underwater Vehicles (AUVs) and tasks involving human diver-AUV coordination. Such missions are gaining increasing popularity with the advent of better control mechanisms and availability of acoustic modems. However, high costs and the lack of useful tools to simulate multiAUV tasks have hindered the ful...

2012
H. Slabbekoorn

Underwater habitats are full of natural sounds from abiotic sources, such as wind and water flow, and biotic sources, such as chorusing fish and snapping shrimps. However, human activities elevate these ambient noise levels artificially. The so-called anthropogenic noise from traffic, industry, and recreational activities concerns an only recently recognized pollution factor underwater which is...

2009
Shaolin Peng

Underwater acoustic communication is widely used in many areas to collect the data from different kinds of sensors deployed underwater or send control information to remote nodes. However, there are many challenges for underwater communication systems because of the characteristics of acoustic propagation in the underwater environment, such as Doppler spread, ambient noise, fading, high propaga...

2017
Huijun Xia Kunde Yang Yuanliang Ma Yong Wang Yaxiong Liu

Generally, many beamforming methods are derived under the assumption of white noise. In practice, the actual underwater ambient noise is complex. As a result, the noise removal capacity of the beamforming method may be deteriorated considerably. Furthermore, in underwater environment with extremely low signal-to-noise ratio (SNR), the performances of the beamforming method may be deteriorated. ...

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