Study on AC Artificially Pollution Flashover Performance of Long Porcelain Insulator String

2015 ◽  
Vol 713-715 ◽  
pp. 975-978 ◽  
Author(s):  
Yan Shi ◽  
Gang Hu ◽  
Yong Chen
Keyword(s):  
Power Function ◽  
Least Square Method ◽  
Least Square ◽  
Experimental Results ◽  
Porcelain Insulator ◽  
Pollution Flashover ◽  
Flashover Voltage ◽  
The One ◽  
The Relationship ◽  
Mutually Independent

In this paper,the relationship between 50% ac flashover voltage (U50) of long porcelain insulator string and ρESDD and ρNSDD was analyzed based on experimental results. It was shown that the relationship between U50 and ρESDD is the same as the one between U50 and ρNSDD, in which the U50 reduces with the increase of ρESDD by a power function, and the influences of ρESDD and ρNSDD on U50 are mutually independent. By using the least square method, the value of exponent of a and b were determined.

Study on AC Artificially Pollution Flashover Performance of EHV Class Insulator String of 32 Units

2013 ◽  
Vol 427-429 ◽  
pp. 1456-1459
Author(s):  
Yan Shi ◽  
Yong Chen ◽  
Shang Zun Yuan
Keyword(s):  
Power Function ◽  
Least Square Method ◽  
Least Square ◽  
Experimental Results ◽  
Pollution Flashover ◽  
Flashover Voltage ◽  
The One ◽  
The Relationship ◽  
Mutually Independent

Study on pollution flashover characteristics of EHV system have great reference on engineering.In this paper,the relationship between 50% ac flashover voltage U50 of class insulator string of 32 units and ρESDD, ρNSDD was analyzed based on experimental results. It was shown that the relationship between U50 and ρESDD is the same as the one between U50 and ρNSDD, in which the U50 reduces with the increase of ρESDD by a power function, and the influences of ρESDD and ρNSDD on U50 are mutually independent. By using the least square method, the value of exponent of a and b were determined.

Approximation of the Kinematics of Foot Joints by Using Passive Elastic Characteristics of Joint

2007 ◽  
Vol 342-343 ◽  
pp. 621-624
Author(s):  
Hyeon Ki Choi ◽  
Si Yeol Kim ◽  
Won Hak Cho
Keyword(s):  
Joint Angle ◽  
Reaction Force ◽  
Force Plate ◽  
Least Square Method ◽  
Least Square ◽  
Biomechanical Analysis ◽  
Clinical Evaluations ◽  
Foot Joints ◽  
The Relationship ◽  
Elastic Characteristics

We investigated the relationship between kinematic and kinetic characteristics of foot joints resisting ground reaction force (GRF). Passive elastic characteristics of joint were obtained from the experiment using three cameras and one force plate. The relationship between joint angle and moment was mathematically modeled by using least square method. The calculated ranges of motion were 7o for TM joint, 4o for TT joint and 20o for MP joint. With the model that relates joint angle and plantar pressure, we could get the kinematic data of the joints which are not available from conventional motion analysis. The model can be used not only for biomechanical analysis which simulates gait but also for the clinical evaluations.

Parameters Identification for Nonlinear Duffing System Based on Wavelet Transformation

2013 ◽  
Vol 357-360 ◽  
pp. 1524-1530
Author(s):  
Shi Zhou ◽  
Dong Mei Huang ◽  
Wei Xin Ren ◽  
Qiong Li Wang
Keyword(s):  
Forced Vibration ◽  
Wavelet Transformation ◽  
Recognition Accuracy ◽  
Vibration Signal ◽  
Least Square Method ◽  
Least Square ◽  
Instantaneous Amplitude ◽  
Approximate Analytical Expression ◽  
Duffing System ◽  
The Relationship

Continuous wavelet transformation is made to identify the parameters of damped harmonic forced vibration Duffing system. With the aid of conversion relationship between the scale and frequency, the solution of nonlinear Duffing equation is adopted by average method, which gained approximate analytical expression for instantaneous amplitude and instantaneous frequency of the system. The nonlinear stiffness coefficient and natural frequency can be gained by least square method and the relationship between recognition accuracy and parameter selection are summarized in the article. Parameter identification method of harmonic forced vibration system is proposed in this paper. Studying the wavelet ridge and corresponding scale by segments to filter out the affects of the simple harmonic motion, to extract systems free vibration signal and to achieve the goal of identifying system parameters.

scholarly journals A Study on the Relationship between Earnings Quality and Capital Cost-Takes the China Listed Companies as a Sample

2021 ◽  
pp. 48-56
Author(s):  
Chih-Yi Hsiao ◽  
Hui-Hui Kuang ◽  
Hui-Ling Li ◽  
Jia-Li Liu
Keyword(s):  
Earnings Management ◽  
Earnings Quality ◽  
Least Square Method ◽  
Listed Companies ◽  
Capital Cost ◽  
Least Square ◽  
Accounting System ◽  
Ordinary Least Square ◽  
Research Findings ◽  
The Relationship

The phenomenon of false financial statements still exists. However, in addition to the risk of being punished, what kind of price do companies have to pay? In recent decades, with China's rapid progress in economic, the relevant accounting system and corporate governance standards are actively improving, and the earnings quality is improving. This paper takes China's listed companies from 2015 to 2019 as samples, and adopts quantile regression supplemented by ordinary least square method to explore the relationship between earnings quality and capital cost. The research findings show that the higher the earnings management, the higher the capital cost, especially for the company with low capital cost. Nevertheless, for the extremely company with high capital cost, earnings management can reduce the capital cost. The research results can provide the focus of regulators of listed companies and reference for the revision of relevant accounting system.

Parameter sensitivity analysis and optimum model of the magnetorheological damper’s Bouc–Wen model

2020 ◽  
pp. 107754632095929
Author(s):  
Min Jiang ◽  
Xiaoting Rui ◽  
Wei Zhu ◽  
Fufeng Yang ◽  
Hongtao Zhu ◽  
...  
Keyword(s):  
Parameter Identification ◽  
Fitness Function ◽  
Least Square Method ◽  
Least Square ◽  
Identification Process ◽  
Long Time ◽  
Method Optimization ◽  
Optimum Model ◽  
The One ◽  
Sensitive Parameters

To overcome the shortcomings of the Bouc–Wen model, such as too many parameters, complex identification process, and long time consuming, the sensitivity of parameters was analyzed. A Bouc–Wen optimum model with sensitive parameters to guarantee calculating accuracy was established. First, according to the results of the magnetorheological damper’s mechanical property test, the sensitivity of Bouc–Wen model’s parameters was analyzed by the one-at-a-time method. Optimization of the Bouc–Wen model was completed. Second, the parameters of the Bouc–Wen optimum model were identified under three harmonic excitations. Compared with the original Bouc–Wen model, the differences of calculation accuracy were 0.0055, 0.0007, and 0.0070 respectively. And the convergence rate of the fitness function for parameter identification increased by 67.89%, 49.94%, and 67.24%, respectively. And the iteration time of 1000 iterations was shortened by 36.52%, 25.95%, and 64.11%, respectively. It indicates that the Bouc–Wen optimum model had higher efficiency and certain accuracy in parameter identification process. Then, the calculation accuracy of Bouc–Wen optimum model with independent and coupled mean parameters were analyzed respectively. Finally, the parameters of the Bouc–Wen optimum model and current were fitted by the least square method. The results showed that the Bouc–Wen optimum model can accurately and efficiently simulate the dynamic characteristics of magnetorheological dampers.

Determination of Johnson Cook Material Model Constants and Their Influence on Machining Simulations of Tungsten Heavy Alloy

2018 ◽  
Author(s):  
Chithajalu Kiran Sagar ◽  
Amrita Priyadarshini ◽  
Amit Kumar Gupta ◽  
Sidharth Kumar Shukla
Keyword(s):  
Least Square Method ◽  
Material Model ◽  
Least Square ◽  
Experimental Results ◽  
Tungsten Heavy Alloy ◽  
Fe Model ◽  
Abc Algorithm ◽  
Bee Colony ◽  
Aircraft Manufacturing ◽  
Heavy Alloys

Tungsten Heavy Alloys (WHA) are used in counterbalance and ballast weights for aerodynamic balancing in fixed and rotary wing aircraft. Manufacturing these components for closer tolerances using machining is a challenging task. The present work aims to develop a 2D Finite Element (FE) model to simulate the chip formation process during machining of WHA using Johnson Cook Material Model (JCMM). The model constants for 95%WHA are determined based on the high strain rate test data using least square method. The calculated values are further optimized using Genetic Algorithm (GA) and Artificial Bee Colony (ABC) algorithm, which are then used as material inputs for FE simulation of machining WHA. The predicted results such as cutting force, chip geometry, shear stress, shear angle are presented and compared with the experimental results under similar cutting conditions. It has been observed that the constants obtained from ABC algorithm show minimum error in the cutting performance measures for all the experimental results.

Localization of Mobile Robot Based on Least Square Method

2013 ◽  
Vol 347-350 ◽  
pp. 808-811
Author(s):  
Jia Lu Li ◽  
Lin Bing Long ◽  
Bao Feng Zhang
Keyword(s):  
Motion Estimation ◽  
Mobile Robot ◽  
Mobile Robots ◽  
Least Squares ◽  
Least Square Method ◽  
Least Square ◽  
Experimental Results ◽  
Sift Algorithm ◽  
Key Techniques ◽  
Point Detection

Localization is the basis for navigation of mobile robots. This paper focuses on key techniques of localization for mobile robots based on vision. Firstly, the specific measures and steps of the algorithm are analyzed and researched in depth. In the study, SIFT algorithm combined with epipolar geometry constraint is used on the environment feature point detection, matching and tracking. And the method of RANSAC combined with the least squares is used to obtain accurate results of the motion estimation. Then the necessary experiments are carried out to verify the correctness and effectiveness of algorithms. The experimental results verified the accuracy of the improved algorithm.

An Identification Method of Failure Mechanism Consistency for Rubber Materials in Accelerated Aging Testing

2016 ◽  
Vol 723 ◽  
pp. 237-241
Author(s):  
Han Zhang ◽  
Yue Li ◽  
Ya Shun Wang
Keyword(s):  
Activation Energy ◽  
Failure Mechanism ◽  
Accelerated Aging ◽  
Least Square Method ◽  
Least Square ◽  
Arrhenius Model ◽  
Rubber Material ◽  
Velocity Constant ◽  
Identification Method ◽  
The Relationship

The failure mechanism of rubber materials under accelerated stress in aging process may be different from that under normal conditions. Therefore, identification of the failure mechanism consistency is necessary for the accelerated aging testing of rubber material. To solve the problem, we study the relationship between the aging velocity of permanent compression set value and aging time. Firstly, according to the relationship, the aging velocity constant is obtained through the least square method. Then, combining with the aging velocity constant, we found that the activation energy is equal to the slope of linear function about Arrhenius model. Based on that failure activation energy keeps same under same failure mechanism, an identification method about failure mechanism consistency is developed. Finally, to demonstrate and validate the proposed method, we take the accelerated aging testing for the nitrile rubber-26 sealing gasket as an example.

Comparing of Coordinate Transformation Based on Total Least Squares and Least Squares

2014 ◽  
Vol 522-524 ◽  
pp. 1211-1214
Author(s):  
Qing Wu Meng ◽  
Lu Meng
Keyword(s):  
Least Squares ◽  
Coordinate Transformation ◽  
Least Square Method ◽  
Coefficient Matrix ◽  
Total Least Squares ◽  
Least Square ◽  
Experimental Results ◽  
Transformation Models ◽  
Total Least Square

The coordinate transformation models based on least square method and total least square are built and discussed. The least square model only includes the errors of observation vectors, the total least square model simultaneously takes into consideration to the errors of observation vectors and the errors of coefficient matrix. The both models are verified and compared in experiment. The experimental results showed that the model of total least square is more in line with actual, and more reasonable than by least square theoretically, and the coordinate transformation solution result of total least square with least square is more near.

Sign in / Sign up

Export Citation Format

Share Document