Influence of Grey System Parameter Identification Method on Prediction of Bearing Capacity of Piles

2011 ◽  
Vol 243-249 ◽  
pp. 2044-2049
Author(s):  
Fang Yang ◽  
Lin Zhu Sun ◽  
Zi Ling Xie ◽  
Ya Gang Zhou
Keyword(s):  
Differential Equation ◽  
Bearing Capacity ◽  
Sequence Data ◽  
Optimization Theory ◽  
Nonlinear Least Squares ◽  
Optimization Method ◽  
Model System ◽  
Grey System ◽  
System Parameters ◽  
Grey Differential Equation

An unequal interval grey model GM (1,1) was established according to the variation characteristics of sequence data about the bearing capacity of overlength piles, and a difference equations was usually adopted to replace the grey differential equation for determining the system parameters of the model; however, great errors would occur when the model thus established was used to predict the bearing capacity of overlength piles, that is, the prediction results would be overestimated or underestimated. In order to improve the prediction accuracy of the model, we established an error objective function based on optimization theory in this study, employed the method of nonlinear least squares to identify the system parameters in the grey differential equation for the bearing capacity of overlength piles, and built an optimization-based grey optimization model. The model system built with optimization method was used to predict the bearing capacity of overlength piles, and the predicted values fit the test values well. In addition, the model system had a higher accuracy, compared with the grey difference model built with difference method; therefore, the model system built with optimization method could provide reference for prediction of the bearing capacity of overlength piles.

scholarly journals Model system parameters influence the sodium hypochlorite susceptibility of endodontic biofilms

2021 ◽  
Author(s):  
R.C.D. Swimberghe ◽  
A. Crabbé ◽  
R.J.G. De Moor ◽  
T. Coenye ◽  
M.A. Meire
Keyword(s):  
Sodium Hypochlorite ◽  
Model System ◽  
System Parameters

A GM(1,N)-based economic cybernetics model for the high-tech industries in China

Kybernetes ◽  
2014 ◽  
Vol 43 (5) ◽  
pp. 672-685 ◽  
Author(s):  
Zheng-Xin Wang
Keyword(s):  
Differential Equation ◽  
Patent Application ◽  
Small Sample ◽  
Total Output ◽  
High Tech ◽  
Data Set ◽  
Content Type ◽  
Fixed Assets ◽  
Grey Differential Equation ◽  
Medical Equipments

Purpose – The purpose of this paper is to propose an economic cybernetics model based on the grey differential equation GM(1,N) for China's high-tech industries and provide the necessary support to assist high-tech industries management departments with their policy making. Design/methodology/approach – Based on the principle of grey differential equation GM(1,N), the grey differential equations of five high-tech industries in China are established using the net fixed assets, labor quantity and patent application quantity as cybernetics variables. After the discretization and first-order subtraction reduction to the simultaneous equation of the five grey models, a linear cybernetics model is resulted in. The structure parameters in the cybernetics system show explicit economic significance and can be identified through least square principle. At last, the actual data in 2004-2010 are introduced to empirically analyze the high-tech industrial system in China. Findings – The cybernetics system for China's high-tech industries are stable, observable, and controllable. On the whole, China's high-tech industries show higher output coefficients of the patent application quantity than those of net fixed assets and labor quantity. This suggests that China's industry development mainly depends on technological innovation rather than capital or labor inputs. It is expected that the total output value of China's high-tech industries will grow at an average annual rate of 15 percent in 2011-2015, with contributions of pharmaceuticals, aircraft and spacecraft, electronic and telecommunication equipments, computers and office equipments, medical equipments and meters by 21, 16, 13, 10, and 28 percent, respectively. In addition, pharmaceuticals, as well as medical equipments and meters, present upward proportions in the gross of Chinese high-tech industries significantly. Electronic and telecommunication equipments, plus computers and office equipments exhibit an obvious decreasing proportion. The proportion of the output value of aircraft and spacecraft is basically stable. Practical implications – Empirical analysis results are helpful for related management departments to formulate reasonable industrial policies to keep the sustained and stable development of the high-tech industries in China. Originality/value – Based on the grey differential equation GM(1,N), this research puts forward an economic cybernetics model for the high-tech industries in China. This model is applicable to the economic system with small sample data set.

Global Time Optimization Method for Dredging Construction Cycles of Trailing Suction Hopper Dredger Based on Grey System Model

2022 ◽  
Vol 148 (2) ◽  
Author(s):  
Shuo Bai ◽  
Mingchao Li ◽  
Qiaorong Lu ◽  
Huijing Tian ◽  
Liang Qin
Keyword(s):  
Optimization Method ◽  
System Model ◽  
Grey System ◽  
Time Optimization ◽  
Global Time ◽  
Grey System Model

Dynamics of a Continuous System With Clearance and Motion Limiting Stops

1999 ◽  
Author(s):  
P. Metallidis ◽  
S. Natsiavas
Keyword(s):  
Piecewise Linear ◽  
Research Work ◽  
Continuous System ◽  
Continuous Model ◽  
Equation Of Motion ◽  
Model System ◽  
Periodic Motions ◽  
System Parameters ◽  
Rigid Rods ◽  
The Stability

Abstract The present study generalises previous research work on the dynamics of discrete oscillators with piecewise linear characteristics and investigates the response of a continuous model system with clearance and motion-limiting constraints. More specifically, in the first part of this work, an analysis is presented for determining exact periodic response of a periodically excited deformable rod, whose motion is constrained by a flexible obstacle. This methodology is based on the exact solution form obtained within response intervals where the system parameters remain constant and its behavior is governed by a linear equation of motion. The unknowns of the problem are subsequently determined by imposing an appropriate set of periodicity and matching conditions. The analytical part is complemented by a suitable method for determining the stability properties of the located periodic motions. In the second part of the study, the analysis is applied to several cases in order to investigate the effect of the system parameters on its dynamics. Special emphasis is placed on comparing these results with results obtained for similar but rigid rods. Finally, direct integration of the equation of motion in selected areas reveals the existence of motions, which are more complicated than the periodic motions determined analytically.

scholarly journals Optimized Digital Controllers for Switching-Mode DC-DC Step-Down Converter

Electronics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 412 ◽  
Author(s):  
Ghulam Abbas ◽  
Jason Gu ◽  
Umar Farooq ◽  
Muhammad Abid ◽  
Ali Raza ◽  
...  
Keyword(s):  
Least Squares ◽  
Dynamic Performance ◽  
Nonlinear Least Squares ◽  
Optimization Method ◽  
Buck Converter ◽  
Digital Controllers ◽  
Real Zeros ◽  
Power Stage ◽  
Step Down ◽  
Zeros And Poles

In this paper, a nonlinear least squares optimization method is employed to optimize the performance of pole-zero-cancellation (PZC)-based digital controllers applied to a switching converter. An extensively used step-down converter operating at 1000 kHz is considered as a plant. In the PZC technique, the adverse effect of the (unwanted) poles of the buck converter power stage is diminished by the complex or real zeros of the compensator. Various combinations of the placement of the compensator zeros and poles can be considered. The compensator zeros and poles are nominally/roughly placed while attempting to cancel the converter poles. Although PZC techniques exhibit satisfactory performance to some extent, there is still room for improvement of the controller performance by readjusting its poles and zeros. The (nominal) digital controller coefficients thus obtained through PZC techniques are retuned intelligently through a nonlinear least squares (NLS) method using the Levenberg-Marquardt (LM) algorithm to ameliorate the static and dynamic performance while minimizing the sum of squares of the error in a quicker way. Effects of nonlinear components such as delay, ADC/DAC quantization error, and so forth contained in the digital control loop on performance and loop stability are also investigated. In order to validate the effectiveness of the optimized PZC techniques and show their supremacy over the traditional PZC techniques and the ones optimized by genetic algorithms (GAs), simulation results based on a MATLAB/Simulink environment are provided. For experimental validation, rapid hardware-in-the-loop (HiL) implementation of the compensated buck converter system is also performed.

On the new model system and framework of grey system theory

2015 ◽  
Author(s):  
Sifeng Liu ◽  
Liangyan Tao ◽  
Naiming Xie ◽  
Yingjie Yang
Keyword(s):  
System Theory ◽  
Model System ◽  
Grey System Theory ◽  
Grey System ◽  
New Model

A Novel Parameter Optimization Method for the Driving System of High-Speed Parallel Robots

2018 ◽  
Vol 10 (4) ◽  
Author(s):  
Xin-Jun Liu ◽  
Gang Han ◽  
Fugui Xie ◽  
Qizhi Meng ◽  
Sai Zhang
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Dynamic Performance ◽  
Optimization Method ◽  
Parallel Robots ◽  
Parameters Optimization ◽  
Driving System ◽  
System Parameters ◽  
Driving Torque ◽  
Instantaneous Acceleration

Driving system parameters optimization, especially the optimal selection of specifications of motor and gearbox, is very important for improving high-speed parallel robots' performance. A very challenging issue is parallel robots' performance evaluation that should be able to illustrate robots' performance accurately and guide driving system parameters optimization effectively. However, this issue is complicated by parallel robots' anisotropic translational and rotational dynamic performance, and the multiparameters of motors and gearboxes. In this paper, by separating the influence of translational and rotational degrees-of-freedom (DOFs) on robots' performance, a new dynamic performance index is proposed to reflect the driving torque in instantaneous acceleration. Then, the influence of driving system's multiparameters on robots' driving torque in instantaneous acceleration and cycle time in continuous motion is investigated. Based on the investigation, an inertia matching index is further derived which is more suitable for minimizing the driving torque of parallel robots with translational and rotational DOFs. A comprehensive parameterized performance atlas is finally established. Based on this atlas, the performance of a high-speed parallel robot developed in this paper can be clearly evaluated, and the optimal combination of motors and gearboxes can be quickly selected to ensure low driving torque and high pick-and-place frequency.

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