Degrees of Freedom of Multi-Mode-Multi-Spatial (MOMS) in Line-of-Sight Channels

2020 ◽  
Author(s):  
Rui NI ◽  
Yi LV ◽  
Qian ZHU ◽  
Guangjian WANG ◽  
Gaoning HE ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Line Of Sight ◽  
Multi Mode

A Multi-Mode Approach for the Nonlinear Vibrations of Circular Cylindrical Shells

2001 ◽  
Author(s):  
Francesco Pellicano ◽  
Marco Amabili ◽  
Michael P. Païdoussis
Keyword(s):  
Degrees Of Freedom ◽  
Nonlinear Vibrations ◽  
Shell Theory ◽  
Cylindrical Shells ◽  
Nonlinear Behavior ◽  
Symbolic Manipulation ◽  
Comparison Functions ◽  
Circular Cylindrical Shells ◽  
Multi Mode

Abstract The nonlinear vibrations of simply supported, circular cylindrical shells, having geometric nonlinearities is analyzed. Donnell’s nonlinear shallow-shell theory is used, and the partial differential equations are spatially discretized by means of the Galerkin procedure, using a large number of degrees of freedom. A symbolic manipulation code is developed for the discretization, allowing an unlimited number of modes. In the displacement expansion particular care is given to the comparison functions in order to reduce as much as possible the dimension of the dynamical system, without losing accuracy. Both driven and companion modes are included, allowing for traveling-wave response of the shell. The fundamental role of the axisymmetric modes, which are included in the expansion, is confirmed and a convergence analysis is performed. The effect of the geometric shell characteristics, radius, length and thickness, on the nonlinear behavior is analyzed.

scholarly journals 3DOF Adaptive Line-Of-Sight Based Proportional Guidance Law for Path Following of AUV in the Presence of Ocean Currents

2019 ◽  
Vol 9 (17) ◽  
pp. 3518 ◽  
Author(s):  
Fengxu Liu ◽  
Yue Shen ◽  
Bo He ◽  
Junhe Wan ◽  
Dianrui Wang ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Path Following ◽  
Lyapunov Theory ◽  
Line Of Sight ◽  
Average Error ◽  
Drift Angle ◽  
Reference Path ◽  
Guidance Law ◽  
Look Ahead ◽  
Three Degrees Of Freedom

In order to achieve high-precision path following of autonomous underwater vehicle (AUV) in the horizontal plane, a three degrees-of-freedom adaptive line-of-sight based proportional (3DOFAPLOS) guidance law is proposed. Firstly, the path point coordinate system is introduced, which is suitable for the conversion of an arbitrary path. Then, the appropriate look-ahead distance is obtained by an improved adaptive line-of-sight (ALOS) according to three degrees-of-freedom (3DOF), including the cross-track error, the curvature of reference path, and the forward speed. Moreover, combining three degrees-of-freedom ALOS (3DOFALOS) with proportional guidance law, the desired heading is calculated considering the drift angle. 3DOFAPLOS has two functions: in the convergence stage, 3DOFALOS plays a leading role, making AUV converge to the path more quickly and smoothly. In the guidance stage, proportional guidance law plays a major role in effectively resisting the influence of drift angle and making AUV sail along the reference path. If the path is curved, 3DOFALOS makes contributions in both stages, adjusting look-ahead distance in real time with respect to curvature. The stability of the designed closed system is proved by Lyapunov theory. Both simulation and experiment results have verified that 3DOFAPLOS has a satisfactory result, which improves tracking performance more than 50% compared with the traditional line-of-sight (LOS). Specifically, the mean average error (MAE) of path following under 3DOFAPLOS can be reduced by about 60%, and the root mean square error (RMSE) can be reduced by about 50% compared with LOS.

Dynamics of bell-nonlocality for two atoms interacting with a vacuum multi-mode noise field

2016 ◽  
Vol 14 (03) ◽  
pp. 1650011 ◽  
Author(s):  
Yu-Jie Liu ◽  
Li Zheng ◽  
Dong-Mei Han ◽  
Huan-Lin Lü ◽  
Tai-Yu Zheng
Keyword(s):  
Degrees Of Freedom ◽  
Internal State ◽  
Bell Inequality ◽  
Entanglement Dynamics ◽  
Noise Field ◽  
Chsh Inequality ◽  
Internal States ◽  
Bell Nonlocality ◽  
Multi Mode ◽  
Spatial Degrees Of Freedom

We investigate the internal-state Bell nonlocal entanglement dynamics, as measured by CHSH inequality of two atoms interacting with a vacuum multi-mode noise field by taking into account the spatial degrees of freedom of the two atoms. The dynamics of Bell nonlocality of the atoms with the atomic internal states being initially in a Werner-type state is studied, by deriving the analytical solutions of the Schrödinger equation, and tracing over the degrees of freedom of the field and the external motion of the two atoms. In addition, through comparison with entanglement as measured by concurrence, we find that the survival time of entanglement is much longer than that of the Bell-inequality violation. And the comparison of the quantum correlation time between two Werner-type states is discussed.

On Cross Flow-Induced Vibration of a Flexible Cylinder

2014 ◽  
Author(s):  
H. Cen ◽  
D. S-K. Ting ◽  
R. Carriveau
Keyword(s):  
Reynolds Number ◽  
Degrees Of Freedom ◽  
Cross Flow ◽  
Mass Ratio ◽  
Flexible Cylinder ◽  
Flow Induced Vibration ◽  
Slowing Down ◽  
Mode Vibration ◽  
Inner Diameter ◽  
Multi Mode

An experiment study on the cross flow-induced vibration of a flexible cylinder with two degrees of freedom had been conducted in a towing tank. The test cylinder was a 45 cm long Tygon tubing with outer and inner diameter of 7.9 mm (5/16 in) and 4.8 mm (3/16 in), giving a mass ratio of 0.77 and an aspect ratio of 56. It was towed from rest up to 1.6 m/s before slowing down to rest again over a distance of 1.6 m in still water, covering the range of Reynolds number from 1500 to 13000 and reduced velocity from 4 to 35. Multi-mode vibration and sudden shift between different modes were observed. The vibration amplitude, frequency and mode were quantified. The results obtained during the brief constant towing speed were expressed in term of the corresponding Reynolds number or reduced velocity. These findings were cast with respect to the existing knowledge in the literature.

scholarly journals Performance Evaluation of 60-GHz-WPAN System Distributed Over Multi-Mode Fiber

2017 ◽  
Vol 63 (4) ◽  
pp. 381-387
Author(s):  
Moussa El Yahyaoui ◽  
Ali El Moussati ◽  
Kamel Haddadi
Keyword(s):  
Channel Coding ◽  
Signal To Noise Ratio ◽  
Line Of Sight ◽  
Area Network ◽  
60 Ghz ◽  
Optical Carrier ◽  
Modulation Format ◽  
Bit Error Ratio ◽  
Low Coverage ◽  
Multi Mode

Abstract The manuscript deals with the assessment of Radio over Fiber (RoF) system including pure electrical baseband, pure radio frequency band centered around 60 GHz, and hybrid radio-optical system at the same RF band using a global simulation. In this work we focus on RoF solution to improve the low coverage of the 60 GHz channel caused by high free-space attenuation. A realistic co-simulation of the Wireless Personal Area Network (WPAN) IEEE802.15.3c-RoF was performed in a residential environment for Line-Of-Sight (LOS) and Non-Line- Of-Sight (NLOS). In this work, we demonstrated a 60 GHz radio on Multi-Mode Fiber (MMF) using Optical Carrier Suppression (OCS) modulation. The BER (Bit Error Ratio) performance of this system is measured by varying the following parameters: optical launched power, fiber length, modulation format, Channel coding and Signal to Noise Ratio. We show that the RoF at 60 GHz can reach a minimum of 300 m of MMF without optical amplifiers followed by a 5 m wireless transmission with BER less than 10-3 in the LOS and NLOS environments.

Study on Motion of Sight Line of Communication Robot in Standby State

2017 ◽  
Vol 21 (4) ◽  
pp. 716-721
Author(s):  
Akinari Kurosu ◽  
Tomomi Hashimoto ◽  
◽  
Keyword(s):  
Social Interactions ◽  
Nonverbal Communication ◽  
Crucial Role ◽  
Degrees Of Freedom ◽  
Line Of Sight ◽  
Two Degrees Of Freedom ◽  
Communication Robot

The crucial role of nonverbal communication by gaze in social interactions has been highlighted. In this study, an eye robot having two degrees-of-freedom was developed as a communication robot, and the motion of the sight line of this robot in a standby state with an absence of communication with people was investigated. We compared and evaluated the impression provided by a robot and a person, who imitated the action of the robot, to observers and demonstrated that both the robot and person provided improved impression if the line of sight is stationary.

Parameter Optimization of Vibration Control System in Multiple DOF Structures

2009 ◽  
Author(s):  
Guixi Li ◽  
Rujian Ma ◽  
Xiaobing Luo
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Parameter Optimization ◽  
Degrees Of Freedom ◽  
Transfer Functions ◽  
Single Mode ◽  
Mode Control ◽  
Magnification Factors ◽  
Optimization Study ◽  
Multi Mode

The parameter optimization and optimal vibration control effects of the multiple tuned mass damper system are studied in this paper by establishing the dynamic model of the multi-mode control of the multi-degree-of-freedom structure and vibration control system. The transfer functions and dynamic magnification factors of the multi-mode control of the multi-degrees-of-freedom structure and vibration control system are derived at first. Then parameter optimization study of the vibration control system was performed, where the minimum of the dynamic magnification factor is used as the optimal objective. Furthermore, the optimal vibration control effects of single mode control and multi-mode control are studied. The application examples are finally given and indicated that this method has the characteristics of better suitability and high accurate.

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