Results 11 to 20 of about 26,129 (212)

Rapid Modeling of the Sound Speed Field in the South China Sea Based on a Comprehensive Optimal LM-BP Artificial Neural Network

Journal of Marine Science and Engineering, 2021
Ocean sound speed is an essential foundation for marine scientific research and marine engineering applications. In this article, a model based on a comprehensive optimal back propagation artificial neural network model is developed.
Jin Huang, Yu Luo, Jian Shi, Xin Ma, Qian-Qian Li, Yan-Yi Li   +5 more
doaj   +1 more source

Underwater passive manoeuvring target tracking with isogradient sound speed profile

IET Radar, Sonar & Navigation, 2022
Compared with the traditional tracking problem, the underwater 3‐D passive manoeuvring target tracking faces the following challenging problems: (1) Since the signal propagation delay is varying and unknown, the relationship between the two adjacent ...
Jun Su, Yaan Li, Wasiq Ali
doaj   +1 more source

Reconstruction of Ocean Front Model Based on Sound Speed Clustering and Its Effectiveness in Ocean Acoustic Forecasting

Applied Sciences, 2021
As a mesoscale phenomenon of the ocean, the ocean front can directly affect the structural characteristics of sound speed profiles and further affect the acoustic propagation characteristics of the sea area.
Yuyao Liu, Wei Chen, Wen Chen, Yu Chen, Lina Ma, Zhou Meng   +5 more
doaj   +1 more source

A Molecularly Defined Midbrain Circuit Mechanism for Sound-Driven Defensive Behavior and Anxiety. [PDF]

Adv Sci (Weinh)
Schematic diagram showing the Cbln2+ ICx–dPAG circuit for sound‐driven defensive and anxiety‐like behaviors. ABSTRACT The innate defense behaviors in response to threatening sounds play a fundamental role in survival. However, the neural circuits that detect threat‐relevant auditory cues and transform them into defensive behaviors remain poorly defined.
Cao J, Lai X, Huo L, Zheng Z, Zhang Q, Ye Z, Wan P, Ma C, Shang C.   +8 more
europepmc   +2 more sources

Centimeter-level-precision seafloor geodetic positioning model with self-structured empirical sound speed profile

Satellite Navigation, 2023
In-field Sound Speed Profile (SSP) measurement is still indispensable for achieving centimeter-level-precision Global Navigation Satellite System (GNSS)-Acoustic (GNSS-A) positioning in current state of the art.
Shuqiang Xue, Baojin Li, Zhen Xiao, Yue Sun, Jingsen Li   +4 more
doaj   +1 more source

Mud sound speed profile constraints from sub-bottom arrival times [PDF]

JASA Express Letters
Arrival times of sub-bottom reflected paths together with co-located direct measurements of the angle of intromission provide narrow constraints on the sediment sound speed profile.
Charles W. Holland
doaj   +1 more source

Mode coupling in a coastal wedge due to quasi-crossing of range-dependent modal eigenvalues [PDF]

JASA Express Letters, 2023
A specific mechanism of mode coupling in a waveguide propagation is studied when two range-dependent eigenvalues approach each other. This phenomenon is analogous to the so-called quasi-crossing of states in atomic physics (Landau–Zener theory).
Yanyu Jiang, Qianchu Zhang, Boris Katsnelson   +2 more
doaj   +1 more source

Geometric stochastic ray propagation using the special Euclidean group [PDF]

JASA Express Letters
This paper describes a stochastic model of ray trajectory propagation through a medium—such as the ocean—which has an uncertain sound speed profile. We frame ray propagation as a geometric fractal Brownian motion process on the special Euclidean group of
Tyler Paine, EeShan Bhatt
doaj   +1 more source

Experimental Results of Underwater Sound Speed Profile Inversion by Few-Shot Multi-Task Learning

Remote Sensing, 2023
Underwater Sound Speed Profile (SSP) distribution is crucial for the propagation mode of acoustic signals, so fast and accurate estimation of SSP is of great importance in building underwater observation systems.
Wei Huang, Jixuan Zhou, Fan Gao, Junting Wang, Tianhe Xu   +4 more
doaj   +1 more source

Passive acoustic estimates of sound speed from vertical line array data in the Nordic Seas [PDF]

JASA Express Letters
In wind-wave driven ambient sound environments, the cross-correlation of acoustic data recorded on vertically separated hydrophones can provide estimates of the average sound speed between hydrophones.
Robert T. Taylor, Megan S. Ballard, Jason D. Sagers, Leah Johnson, Harper Simmons   +4 more
doaj   +1 more source