A geometric model for the spatial correlation of an acoustic vector field in surface-generated noise

2012 ◽  
Vol 11 (1) ◽  
pp. 119-125 ◽  
Author(s):  
Yiwang Huang ◽  
Qunyan Ren ◽  
Ting Li
Keyword(s):  
Vector Field ◽  
Spatial Correlation ◽  
Geometric Model

scholarly journals A spatial correlation model for the horizontal non-isotropic ocean ambient noise vector field

2017 ◽  
Vol 36 (2) ◽  
pp. 124-137 ◽  
Author(s):  
Jianbo Zhou ◽  
Shengchun Piao ◽  
Yiwang Huang ◽  
Shizhao Zhang ◽  
Ke Qu
Keyword(s):  
Vector Field ◽  
Spatial Correlation ◽  
Ambient Noise ◽  
Vibration Velocity ◽  
Ocean Bottom ◽  
Noise Field ◽  
Sonar System ◽  
Sensors Array ◽  
Ocean Environment ◽  
Von Mises

The ocean ambient noise is one of interference fields of underwater acoustic channel. The design and use of any sonar system are bound to be affected by ocean ambient noise, so to research the spatial correlation characteristics of noise field is of positive significance to improving the performance of sonar system. Only wind-generated noise is considered in most existing ambient noise models. In this case, the noise field is isotropic in horizontal direction. However, due to those influencing factors, like rainfall, ships and windstorm, etc. for a real ocean environment, noise field becomes anisotropic horizontally and the spatial structure of ambient field also changes correspondingly. This paper presents a spatial correlation of the acoustic vector field of anisotropic field by introducing Von Mises probability distribution to describe horizontal directivity. Closed-form expressions are derived which relate the cross-correlation among the sound pressure and three orthogonal components of vibration velocity, besides, the influence of the non-uniformity of noise field on the correlation characteristics of noise vector field was analysed. The model presented in this paper can provide theoretical guidance for the design and application of vector sensors array. Furthermore, the achievement could be applied to front extraction, Green’s function extraction, inversion for ocean bottom parameters, and so on.

Adaptive Modular Vector Field Control for Robot Contact Tasks in Uncertain Environments

2004 ◽  
Vol 16 (4) ◽  
pp. 374-380 ◽  
Author(s):  
Yohei Saitoh ◽  
◽  
Zhiwei Luo ◽  
Keiji Watanabe ◽  
Keyword(s):  
Vector Field ◽  
Vector Fields ◽  
Force Feedback ◽  
Robot Manipulator ◽  
Geometric Model ◽  
Geometric Constraints ◽  
Robot Dynamics ◽  
Uncertain Environments ◽  
Field Control ◽  
Environment Simulation

We propose adaptive modular vector field control (AMVFC) for a robot manipulator to interact with uncertain environmental geometric constraints. Starting from an uncertain geometric model of the environment, we first parameterize the desired velocity vector field of the robot using the weighted combination of a set of basis vector fields. Then, to overcome the influence of environmental model uncertainty, we add force feedback to adjust robot dynamics and the weight parameters of the desired velocity field for the robot to approach the real environment. Simulation of a robot interacting with uncertain circles and an ellipse demonstrates the effectiveness of our approach.

scholarly journals Modeling of spatial correlation characteristics of broadband ocean ambient noise vector field

2022 ◽  
Vol 71 (2) ◽  
pp. 024301-024301
Author(s):  
Ren Chao ◽  
◽  
Huang Yi-Wang ◽  
Xia Zhi ◽  
◽  
...  
Keyword(s):  
Vector Field ◽  
Spatial Correlation ◽  
Ambient Noise

ALGEBRA OF PREDICATES AND RELATED GEOMETRIC MODELS CREATION IN REGARDS OF UNIFIED STATE EXAM IN INFORMATICS (RUSSIAN EGE)

2019 ◽  
pp. 40-47
Author(s):  
E. A. Mironchik
Keyword(s):  
Geometric Model ◽  
Main Idea ◽  
Formal Logic ◽  
High Complexity ◽  
Geometric Models ◽  
Complexity Problem ◽  
Logical Expression ◽  
State Examination

The article discusses the method of solving the task 18 on the Unified State Examination in Informatics (Russian EGE). The main idea of the method is to write the conditions of the problem utilizing the language of formal logic, using elementary predicates. According to the laws of logic the resulting complex logical expression would be transformed into an expression, according to which a geometric model is supposed to be constructed which allows to obtain an answer. The described algorithm does allow high complexity problem to be converted into a simple one.

Comparison of Nonlinear Spatial Correlation Models by the Influence of the Data Augmentation to the Classification Risk

2002 ◽  
Vol 7 (1) ◽  
pp. 31-42
Author(s):  
J. Šaltytė ◽  
K. Dučinskas
Keyword(s):  
Spatial Correlation ◽  
Random Fields ◽  
Data Augmentation ◽  
Gaussian Random Fields ◽  
Classification Rule ◽  
Numerical Comparison ◽  
First Order ◽  
Bayesian Risk ◽  
Correlation Models

The Bayesian classification rule used for the classification of the observations of the (second-order) stationary Gaussian random fields with different means and common factorised covariance matrices is investigated. The influence of the observed data augmentation to the Bayesian risk is examined for three different nonlinear widely applicable spatial correlation models. The explicit expression of the Bayesian risk for the classification of augmented data is derived. Numerical comparison of these models by the variability of Bayesian risk in case of the first-order neighbourhood scheme is performed.

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