Dynamics of the Head-Neck Complex in Response to the Trunk Horizontal Vibration: Modeling and Identification

2003 ◽  
Vol 125 (4) ◽  
pp. 533-539 ◽  
Author(s):  
Mohammad A. Fard ◽  
Tadashi Ishihara ◽  
Hikaru Inooka
Keyword(s):  
Mathematical Model ◽  
Dynamic Response ◽  
Fourth Order ◽  
Optimization Method ◽  
Horizontal Vibration ◽  
Domain Identification ◽  
Viscoelastic Parameters ◽  
Resonance Frequencies ◽  
Fourth Order Model ◽  
Head Neck

Although many studies exist concerning the influence of seat vibration on the head in the seated human body, the dynamic response of the head-neck complex (HNC) to the trunk vibration has not been well investigated. Little quantitative knowledge exists about viscoelastic parameters of the neck. In this study, the dynamics of the HNC is identified when it is exposed to the trunk horizontal (fore-and-aft) vibration. The frequency response functions between the HNC angular velocity and the trunk horizontal acceleration, corresponding to four volunteers, are obtained in the frequency range of 0.5 Hz to 10 Hz. A fourth-order mathematical model, derived by considering a double-inverted-pendulum model for the HNC, is designed to simulate the dynamic response of the HNC to the trunk horizontal vibration. The frequency domain identification method is used to determine the coefficients of the mathematical model of the HNC. Good agreement has been obtained between experimental and simulation results. This indicates that the system, similar to the designed fourth-order model, has mainly two resonance frequencies. The viscoelastic parameters of the neck, including the spring and damping coefficients, are then obtained by use of the optimization method.

scholarly journals Mathematical Model of the Dynamic Action of the Controlled Vibration Exciter on the Processed Medium of Mixer with Toroidal Working Container

2018 ◽  
Vol 7 (3.2) ◽  
pp. 478
Author(s):  
Serhii Zhyhylii ◽  
Maksym Kharchenko ◽  
Julia Katella
Keyword(s):  
Mathematical Model ◽  
Force Field ◽  
Dynamic Balance ◽  
External Action ◽  
Vibration Exciter ◽  
Turn Angle ◽  
Dynamic Action ◽  
Resonance Frequencies ◽  
Balance State ◽  
Intermediate Resonance

Vibration mixers are technological machines that are meant for mixing of different processed medium. A driving force in such machines is realizing by oscillation exciter. In this article, the constructive scheme of the vibration mixer is introduced. Such a mixer has the toroidal working container and is equipped with controlled mechanical centrifugal unbalanced exciters of oscillations with a vertically located unbalanced shaft. The work principle of one of the possible configurations in this exciter is considered and provided. One inflexible and two mobile unbalances are strengthen on its unbalanced shaft. The mobile unbalances by means of independent external action, that is caused by mechanism for managing of mobile unbalances, have an opportunity to change synchronously its positions on the unbalanced shaft directly in time of mixer’s work. The centrifugal inertia forces of inflexible and mobile unbalances make the dynamic wrench that consists of the main vector  and the main moment  and rotates with unbalanced shaft. It is determined that the value of the main vector  and the main moment  evaluate the dynamic action of this vibration exciter to the mixer’s working container. The mathematical model of the dynamic action of oscillator exciter on the processed medium of mixer with the toroidal working container is received. Depending on the value of turn angle of mobile unbalances from its starting positions exciter: a) staying in the dynamic balance state; b) is generating the translation force field; c) generates the wrench force field of this or that direction. These opportunities of controlled vibration exciter firmly provide anfractuous circulative motion of the processed medium on the volume of the mixer’s working container. Using of controlled exciter also leaves out the transfers through intermediate resonance frequencies. As its starting and stopping happen in a dynamic balance state, so it leaves out the possibility of manifestation of the “Sommerfeld’s effect” that is harmful for the driven motor, improves the constructive availability of the vibration mixer and increases its efficiency and life duration. 

scholarly journals Image denoising using anisotropic second and fourth order diffusions based on gradient vector convolution

2012 ◽  
Vol 9 (4) ◽  
pp. 1493-1511 ◽  
Author(s):  
Huaibin Wang ◽  
Yuanquan Wang ◽  
Wenqi Ren
Keyword(s):  
Image Denoising ◽  
Fourth Order ◽  
Numerical Stability ◽  
Anisotropic Diffusion ◽  
Computational Cost ◽  
Gradient Vector ◽  
Order Model ◽  
Robustness To Noise ◽  
Fourth Order Model ◽  
Low Computational Cost

In this paper, novel second order and fourth order diffusion models are proposed for image denoising. Both models are based on the gradient vector convolution (GVC) model. The second model is coined by incorporating the GVC model into the anisotropic diffusion model and the fourth order one is by introducing the GVC to the You-Kaveh fourth order model. Since the GVC model can be implemented in real time using the FFT and possesses high robustness to noise, both proposed models have many advantages over traditional ones, such as low computational cost, high numerical stability and remarkable denoising effect. Moreover, the proposed fourth order model is an anisotropic filter, so it can obviously improve the ability of edge and texture preserving except for further improvement of denoising. Some experiments are presented to demonstrate the effectiveness of the proposed models.

Implementation of Genetic-Algorithm-Based Forecasting Model to Power System Problems

2018 ◽  
pp. 140-155
Author(s):  
Sajad Madadi ◽  
Morteza Nazari-Heris ◽  
Behnam Mohammadi-Ivatloo ◽  
Sajjad Tohidi
Keyword(s):  
Genetic Algorithm ◽  
Mathematical Model ◽  
Power System ◽  
Load Forecasting ◽  
Wind Farms ◽  
Optimization Method ◽  
Forecasting Model ◽  
Renewable Generation ◽  
Forecasting Methods ◽  
Pool Market

Power system includes many types of markets. Such markets are generally cleared at certain times, whereas market participators have to determine their operational plans before meeting the actual conditions. Therefore, forecasting methods can assist market players. Forecasting methods are applied to forecast electricity demand. The unknown conditions in the power system are increased by integration of renewable generation units. Forecasting methods, which are used for the load forecasting, are updated because the output power of renewable generation units such as wind farms and photovoltaic (PV) panels have more deviation than power demand. The pool market can be introduced as other parameter that is forecasted by market players. In this chapter, the authors investigate a mathematical model for forecasting of wind. Then, the forecasting model is proposed. Genetic algorithm is applied as an optimization method to handle delay associated with wind forecasting.

Application of Fuzzy Logic and Fuzzy Optimization Techniques in Medical Image Processing

Biometrics ◽  
2017 ◽  
pp. 907-932 ◽  
Author(s):  
Niladri Sekhar Datta ◽  
Himadri Sekhar Dutta ◽  
Koushik Majumder
Keyword(s):  
Mathematical Model ◽  
Fuzzy Logic ◽  
Optimization Technique ◽  
Fuzzy Optimization ◽  
Fuzzy Model ◽  
Optimization Method ◽  
Fuzzy Modeling ◽  
Optimization Techniques ◽  
Fuzzy Variables ◽  
Truth Value

Fuzzy logic deals with approximate rather than fixed and exact reasoning. Fuzzy variables may have a truth value that ranges in degree between 0 and 1; extended to handle the concept of partial truth where the truth value may range between completely true or completely false. This computational logic uses truth degrees as a mathematical model of the vagueness phenomenon while probability is a mathematical model of ignorance. A huge number of complex problems may be solve using Fuzzy logic specifically Fuzzy modeling and optimization method. Fuzzy modeling is the understanding of the problem and analysis of the Fuzzy information where the Fuzzy optimization solves Fuzzy model optimally using optimization techniques via membership functions. In this research article authors describe the Fuzzy rules and its application and the different types of well known problems solved by the Fuzzy optimization technique.

Extended validation of a ground-based three-axis spacecraft simulator model

2020 ◽  
pp. 095441002093896
Author(s):  
H Sh Ousaloo ◽  
Gh Sharifi ◽  
B Akbarinia
Keyword(s):  
Mathematical Model ◽  
Attitude Control ◽  
Aerodynamic Drag ◽  
Center Of Mass ◽  
Model Development ◽  
Optimization Method ◽  
Experimental Results ◽  
Spacecraft Dynamics ◽  
Detailed Model ◽  
Mass Properties

The ground-based spacecraft dynamics simulator plays an important role in the implementation and validation of attitude control scenarios before a mission. The development of a comprehensive mathematical model of the platform is one of the indispensable and challenging steps during the control design process. A precise mathematical model should include mass properties, disturbances forces, mathematical models of actuators and uncertainties. This paper presents an approach for synthesizing a set of trajectories scenarios to estimate the platform inertia tensor, center of mass and aerodynamic drag coefficients. Reaction wheel drag torque is also estimated for having better performance. In order to verify the estimation techniques, a dynamics model of the satellite simulator using MATLAB software was developed, and the problem reduces to a parameter estimation problem to match the experimental results obtained from the simulator using a classical Lenevnberg-Marquardt optimization method. The process of parameter identification and mathematical model development has implemented on a three-axis spherical satellite simulator using air bearing, and several experiments are performed to validate the results. For validation of the simulator model, the model and experimental results must be carefully matched. The experimental results demonstrate that step-by-step implementation of this scenario leads to a detailed model of the platform which can be employed to design and develop control algorithms.

scholarly journals Modified grey wolf method for optimization of PM motors

2019 ◽  
Vol 28 ◽  
pp. 01020
Author(s):  
Łukasz Knypiński
Keyword(s):  
Mathematical Model ◽  
Permanent Magnet ◽  
Permanent Magnet Synchronous Motor ◽  
Computer Software ◽  
Optimization Procedure ◽  
Optimization Method ◽  
Grey Wolf ◽  
Electromagnetic Devices ◽  
The Mathematical Model ◽  
Grey Wolf Algorithm

The paper presents an algorithm and computer software for the optimization of electromagnetic devices. The mathematical model of the optimization method was presented. The modification of the classical grey wolf algorithm was developed. The modification consists in decreasing the coefficient responsible for the possibility of migration individuals in the permissible area of solved task. The optimization procedure was elaborated in the Borland Delphi environment. The optimization of the rotor of the line-start permanent magnet synchronous motor has been carried out. It has been pointed out that the grey wolf algorithm is effective method for optimization of electromagnetic devices.

scholarly journals Frequency Diversity Array for Near-Field Focusing

Electronics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 958
Author(s):  
Xu Han ◽  
Shuai Ding ◽  
Yongmao Huang ◽  
Yuliang Zhou ◽  
Huan Tang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Numerical Methods ◽  
Numerical Optimization ◽  
Near Field ◽  
Optimization Method ◽  
Frequency Diversity ◽  
Initial Amplitude ◽  
Full Wave ◽  
Circular Arrays ◽  
Working Frequency

In this study, a numerical optimization method is proposed to achieve the near-field focusing of square arrays and circular arrays. This method introduced the frequency diversity array (FDA) approach to change the initial amplitude and working frequency. By adjusting the working state of each antenna, the field distribution on any plane can be artificially controlled. To analyze the FDA, a mathematical model for the FDA has been built and the model has been optimized by a numerical algorithm. The results of two different kinds of arrays are verified by numerical methods and full-wave simulation.

A mathematical model to describe the dynamic response of a spruce tree to the wind

Trees ◽  
1998 ◽  
Vol 12 (6) ◽  
pp. 385 ◽  
Author(s):  
Tobias Kerzenmacher ◽  
Barry Gardiner
Keyword(s):  
Mathematical Model ◽  
Dynamic Response

Research on Mathematical Model and Calibration of Weighing System by Digital Addition

2012 ◽  
Vol 151 ◽  
pp. 101-104
Author(s):  
Chao Fu Zhu ◽  
Shu Jian Ji ◽  
Jin Long Zhao
Keyword(s):  
Mathematical Model ◽  
Calibration Method ◽  
Optimization Method ◽  
Load Cells ◽  
On Line ◽  
The Mathematical Model ◽  
Multiple Load

In practice the method is widely used, by which a gravity is measured using multiple load cells. A weighing system is introduced in this paper, in which a gravity is measured by multiple load cells with digital addition. The mathematical model of weighing system with digital addition is established. Normal calibration method is not suitable for the on-line calibration of weighing system with digital addition. When the mathematical model is given, the accurate on-line calibration of weighing system with digital addition is achieved by using optimization method.

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