Structural Parameters Optimization of Parallel Stable Platform Based on Physical Programming

2012 ◽  
Vol 215-216 ◽  
pp. 187-192
Author(s):  
Zhong Hui Dong ◽  
Hong Sheng Ding ◽  
Fang Jiang ◽  
Zhi Chen Huang ◽  
Tie Fu
Keyword(s):  
Optimization Problem ◽  
Jacobi Matrix ◽  
Structural Parameters ◽  
Parameters Optimization ◽  
Evaluation Index ◽  
Physical Programming ◽  
Preference Functions ◽  
Matrix Condition Number ◽  
Working Performance ◽  
Matrix Condition

Based on the parallel stable platform of 6-UPS, Jacobi matrix condition number and driving force of six rods are respectively identified as kinematics evaluation index and dynamics evaluation index of the parallel stable platform. By using physical programming preference functions the comprehensive preference function are constructed. Thus, a multi-objective optimization problem is formulated as a single objective optimization problem. Structural parameters with best working performance are computed by the genetic algorithm. Simulation results in Matlab show that the performance of optimization platform has been improved.

Optimization of Semimagnetic Semiconductor-Based Nanostructures for Spintronic Applications

2006 ◽  
Vol 518 ◽  
pp. 35-40
Author(s):  
J. Radovanović ◽  
V. Milanović ◽  
Z. Ikonić ◽  
D. Indjin
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Simulated Annealing Algorithm ◽  
Structural Parameters ◽  
Zeeman Effect ◽  
Parameters Optimization ◽  
Potential Barriers ◽  
Annealing Algorithm ◽  
Electrical Bias ◽  
Spin Filtering

We have analyzed the spin-filtering effects of the electron current in asymmetric ZnSe/Zn1-xMnxSe multilayer structures, under the influence of both an external magnetic field and a bias voltage. In this type of semiconductor systems, conduction band electrons interact with 3d electrons of the magnetic Mn2+ ions. Because of this sp-d exchange interaction, an external magnetic field modulates the effective potential profile seen by spin-up and spin-down electrons, giving rise to a large Zeeman effect. It is found that the degree of spin polarization changes significantly when the electrical bias is switched from forward to reverse, thus the proposed structure displays obvious behavior of spin-filter diode. This originates from the effective “lifting” of the potential for spin-up electrons, which tunnel through actual potential barriers. Structural parameters optimization, with the goal of maximizing the spin-filtering coefficient, was performed by using simulated annealing algorithm. The described effect may be important for designing new tunable spin-based multifunctional semiconductor devices.

Stability analysis of a discrete-time system with a variable-, fractional-order controller

2010 ◽  
Vol 58 (4) ◽  
pp. 613-619 ◽  
Author(s):  
P. Ostalczyk
Keyword(s):  
Stability Analysis ◽  
Fractional Order ◽  
Discrete Time ◽  
Closed Loop ◽  
Control Strategies ◽  
Discrete Time System ◽  
Time System ◽  
Matrix Condition Number ◽  
Fractional Order Controller ◽  
Matrix Condition

Stability analysis of a discrete-time system with a variable-, fractional-order controllerVariable, fractional-order backward difference is a generalisation of commonly known difference or sum. Equations with these differences can be used to describe a variable-, fractional order digital control strategies. One should mention, that classical tools such as a state-space description and discrete transfer function cannot be used in the analysis and synthesis of such a type of systems. Equations describing a closed-loop system are proposed. They contain square matrices imitating the action of matrices in the system polynomial matrix description. This paper focuses on the stability analysis of a closed-loop SISO linear system with a controller described by the equations mentioned. A stability condition based on a transient denominator matrix condition number is proposed. Investigations are supported by two numerical examples.

Mill Gear Box of Intelligent Diagnosis Based on Support Vector Machine Parameters Optimization

2014 ◽  
Vol 697 ◽  
pp. 239-243 ◽  
Author(s):  
Xiao Hui Liu ◽  
Yong Gang Xu ◽  
De Ying Guo ◽  
Fei Liu
Keyword(s):  
Genetic Algorithm ◽  
Support Vector Machine ◽  
Rolling Mill ◽  
Optimal Parameter ◽  
Structural Parameters ◽  
Parameters Optimization ◽  
Support Vector ◽  
Intelligent Diagnosis ◽  
Gear Box ◽  
Parameter Values

For mill gearbox fault detection problems, and puts forward combining support vector machine (SVM) and genetic algorithm, is applied to rolling mill gear box fault intelligent diagnosis methods. The choice of parameters of support vector machine (SVM) is a very important for the SVM performance evaluation factors. For the selection of structural parameters of support vector machine (SVM) with no theoretical support, select and difficult cases, in order to reduce the SVM in this respect, puts forward the genetic algorithm to optimize parameters, and the algorithm of the model is applied to rolling mill gear box in intelligent diagnosis, using the global searching property of genetic algorithm and support vector machine (SVM) of the optimal parameter values. Results showed that the suitable avoided into local solution optimization, the method to improve the diagnostic accuracy and is a very effective method of parameter optimization, and intelligent diagnosis for rolling mill gear box provides an effective method.

The inverse problem of bimorph mirror tuning on a beamline

2011 ◽  
Vol 18 (6) ◽  
pp. 930-937 ◽  
Author(s):  
Rong Huang
Keyword(s):  
Inverse Problem ◽  
Tikhonov Regularization ◽  
Measurement Errors ◽  
Regularization Parameter ◽  
X Rays ◽  
The Matrix ◽  
Matrix Condition Number ◽  
Matrix Condition ◽  
Safety Limit

One of the challenges of tuning bimorph mirrors with many electrodes is that the calculated focusing voltages can be different by more than the safety limit (such as 500 V for the mirrors used at 17-ID at the Advanced Photon Source) between adjacent electrodes. A study of this problem at 17-ID revealed that the inverse problem of the tuningin situ, using X-rays, became ill-conditioned when the number of electrodes was large and the calculated focusing voltages were contaminated with measurement errors. Increasing the number of beamlets during the tuning could reduce the matrix condition number in the problem, but obtaining voltages with variation below the safety limit was still not always guaranteed and multiple iterations of tuning were often required. Applying Tikhonov regularization and using the L-curve criterion for the determination of the regularization parameter made it straightforward to obtain focusing voltages with well behaved variations. Some characteristics of the tuning results obtained using Tikhonov regularization are given in this paper.

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