On the Modeling and Simulation of Friction

1991 ◽  
Vol 113 (3) ◽  
pp. 354-362 ◽  
Author(s):  
D. A. Haessig ◽  
B. Friedland
Keyword(s):  
Modeling And Simulation ◽  
Experimental Observation ◽  
Friction Force ◽  
Closed Loop ◽  
Physical Phenomenon ◽  
Classical Model ◽  
The Other ◽  
Simulation Experiments ◽  
New Models ◽  
Integrator Model

Two new models for “slip-stick” friction are presented. One, called the “bristle model,” is an approximation designed to capture the physical phenomenon of sticking. This model is relatively inefficient numerically. The other model, called the “reset integrator model,” does not capture the details of the sticking phenomenon, but is numerically efficient and exhibits behavior similar to the model proposed by Karnopp in 1985. All three of these models and the Dahl model are preferable to the classical model, which poorly represents the friction force at zero velocity. Simulation experiments show that the Karnopp model, the Dahl model, and the new models give similar results in two examples. In a closed-loop example, the classical model predicts a limit cycle which is not observed in the laboratory. The Karnopp model, the Dahl model, and the new models, on the other hand, agree with the experimental observation.

Inclusive Citizenship Beyond the Capacity Contract

2017 ◽  
pp. 837-860
Author(s):  
Will Kymlicka ◽  
Sue Donaldson
Keyword(s):  
Cognitive Disabilities ◽  
The Other ◽  
Other Hand ◽  
New Models ◽  
Political Deliberation ◽  
The One

There is deep tension within mainstream citizenship theory. On the one hand, citizenship is often defined in terms of social membership, such that all those affected or all those governed should be part of the demos. On the other hand, citizenship is often limited by an implicit “capacity contract” to those with sophisticated cognitive and linguistic capacities to engage in rational political deliberation, thereby excluding children, people with cognitive disabilities, and animals, who are relegated to a nebulous (and neglected) status of wardship. This chapter explores this tension between these two accounts, and argues that we should abandon the capacity contract as both theoretically arbitrary and politically pernicious. Citizenship should include all members of society, and this in turn requires new models of (interdependent) agency that enable all members to participate in shaping the society and laws by which they are governed.

scholarly journals Commensurate and Non-Commensurate Fractional-Order Discrete Models of an Electric Individual-Wheel Drive on an Autonomous Platform

Entropy ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. 300
Author(s):  
Marcin Bąkała ◽  
Piotr Duch ◽  
J. A. Tenreiro Machado ◽  
Piotr Ostalczyk ◽  
Dominik Sankowski
Keyword(s):  
Fractional Order ◽  
Closed Loop ◽  
Linear Time ◽  
Classical Model ◽  
Linear Difference Equation ◽  
Discrete Models ◽  
Measured Velocity ◽  
Linear Time Invariant ◽  
Wheel Drive ◽  
Time Invariant

This paper presents integer and linear time-invariant fractional order (FO) models of a closed-loop electric individual-wheel drive implemented on an autonomous platform. Two discrete-time FO models are tested: non-commensurate and commensurate. A classical model described by the second-order linear difference equation is used as the reference. According to the sum of the squared error criterion (SSE), we compare a two-parameter integer order model with four-parameter non-commensurate and three-parameter commensurate FO descriptions. The computer simulation results are compared with the measured velocity of a real autonomous platform powered by a closed-loop electric individual-wheel drive.

A Digital (3D) Reconstruction of a Lost Planetarium

2019 ◽  
Vol 3 (2) ◽  
pp. 91-117
Author(s):  
Ioannis S Diolatzis ◽  
Gerasimos Pavlogeorgatos
Keyword(s):  
3D Reconstruction ◽  
Modeling And Simulation ◽  
3D Modeling ◽  
Planetary System ◽  
Simulation Software ◽  
The Other ◽  
Planetary Motion ◽  
Back Door ◽  
Advanced Knowledge

After many years of research, it has been concluded that Antikythera mechanism is a more complicated device than initially was thought. Recently, the rapidly increasing development of 3D modeling and simulation software, resulted in attempts to recreate the mechanism's 3D construction. These 3D replicas are based on advanced knowledge, gathered by the study of the mechanism remnants or the deciphered inscription on its surfaces. The latest decrypted inscriptions on the back door of the mechanism refers to planetary motion, which might be illustrated by a planetarium formation, which is absent from the remains of Antikythera mechanism. The authors propose a 3D reconstruction of this alleged planetarium, as a possible sequence of the existed mechanism's remains, compatible with the surviving inscriptions. Specifically, the authors introduce a lot of constructional differentiations compared to the other suggested, focusing mainly on measurements accuracy which this planetary system could perform.

scholarly journals TSLRF: Two-Stage Algorithm Based on Least Angle Regression and Random Forest in genome-wide association studies

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jiali Sun ◽  
Qingtai Wu ◽  
Dafeng Shen ◽  
Yangjun Wen ◽  
Fengrong Liu ◽  
...  
Keyword(s):  
Machine Learning ◽  
Random Forest ◽  
The Other ◽  
New Method ◽  
Genome Wide Association ◽  
High Dimensional ◽  
Simulation Experiments ◽  
Machine Learning Methods ◽  
Least Angle Regression ◽  
Genome Wide

AbstractOne of the most important tasks in genome-wide association analysis (GWAS) is the detection of single-nucleotide polymorphisms (SNPs) which are related to target traits. With the development of sequencing technology, traditional statistical methods are difficult to analyze the corresponding high-dimensional massive data or SNPs. Recently, machine learning methods have become more popular in high-dimensional genetic data analysis for their fast computation speed. However, most of machine learning methods have several drawbacks, such as poor generalization ability, over-fitting, unsatisfactory classification and low detection accuracy. This study proposed a two-stage algorithm based on least angle regression and random forest (TSLRF), which firstly considered the control of population structure and polygenic effects, then selected the SNPs that were potentially related to target traits by using least angle regression (LARS), furtherly analyzed this variable subset using random forest (RF) to detect quantitative trait nucleotides (QTNs) associated with target traits. The new method has more powerful detection in simulation experiments and real data analyses. The results of simulation experiments showed that, compared with the existing approaches, the new method effectively improved the detection ability of QTNs and model fitting degree, and required less calculation time. In addition, the new method significantly distinguished QTNs and other SNPs. Subsequently, the new method was applied to analyze five flowering-related traits in Arabidopsis. The results showed that, the distinction between QTNs and unrelated SNPs was more significant than the other methods. The new method detected 60 genes confirmed to be related to the target trait, which was significantly higher than the other methods, and simultaneously detected multiple gene clusters associated with the target trait.

scholarly journals Fusion of External and Internal Prior Information for the Removal of Gaussian Noise in Images

2020 ◽  
Vol 6 (10) ◽  
pp. 103
Author(s):  
Ali S. Awad
Keyword(s):  
Gaussian Noise ◽  
Prior Information ◽  
Signal To Noise Ratio ◽  
Principal Component ◽  
The Other ◽  
Noisy Image ◽  
Simulation Experiments ◽  
Two Dimensional Image ◽  
Pixel Location ◽  
Image Pixels

In this paper, a new method for the removal of Gaussian noise based on two types of prior information is described. The first type of prior information is internal, based on the similarities between the pixels in the noisy image, and the other is external, based on the index or pixel location in the image. The proposed method focuses on leveraging these two types of prior information to obtain tangible results. To this end, very similar patches are collected from the noisy image. This is done by sorting the image pixels in ascending order and then placing them in consecutive rows in a new two-dimensional image. Henceforth, a principal component analysis is applied on the patch matrix to help remove the small noisy components. Since the restored pixels are similar or close in values to those in the clean image, it is preferable to arrange them using indices similar to those of the clean pixels. Simulation experiments show that outstanding results are achieved, compared to other known methods, either in terms of image visual quality or peak signal to noise ratio. Specifically, once the proper indices are used, the proposed method achieves PSNR value better than the other well-known methods by >1.5 dB in all the simulation experiments.

scholarly journals Experimental Observation Of Nonlinear Vibrations Using A Closed-Loop Vibration System

2015 ◽  
Vol 22 (4) ◽  
pp. 559-564 ◽  
Author(s):  
Everaldo de Barros ◽  
Carlos d’Andrade Souto ◽  
Mauro Hugo Mathias
Keyword(s):  
Experimental Observation ◽  
Nonlinear Vibrations ◽  
Closed Loop ◽  
Response Spectrum ◽  
Excitation Frequency ◽  
Excitation Amplitude ◽  
Experimental Results ◽  
Vibration System ◽  
Response Curves ◽  
Flexural Mode

Abstract This paper presents experimental observation of nonlinear vibrations in the response of a flexible cantilever beam to transverse harmonic base excitations around its flexural mode frequencies. In the experimental setup, instead of manual control of the signal excitation frequency and amplitude, a closed-loop vibration system is used to keep the excitation amplitude constant during the frequency sweep and to increase confidence in the experimental results. The experimental results show the presence of the third mode in the response when varying the excitation frequency around the fourth mode. The frequency-response curves, response spectrum and Poincaré plots were used for characterization of nonlinear dynamic behaviour of the beam.

scholarly journals Circular Formation Control of Multiagent Systems with Any Preset Phase Arrangement

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Lina Jin ◽  
Shuanghe Yu ◽  
Dongxu Ren
Keyword(s):  
Control Problem ◽  
Multiagent Systems ◽  
Formation Control ◽  
Closed Loop ◽  
Phase Distribution ◽  
The Other ◽  
Control Law ◽  
Closed Loop System ◽  
The Stability ◽  
Phase Arrangement

This paper deals with the circular formation control problem of multiagent systems for achieving any preset phase distribution. The control problem is decomposed into two parts: the first is to drive all the agents to a circle which either needs a target or not and the other is to arrange them in positions distributed on the circle according to the preset relative phases. The first part is solved by designing a circular motion control law to push the agents to approach a rotating transformed trajectory, and the other is settled using a phase-distributed protocol to decide the agents’ positioning on the circle, where the ring topology is adopted such that each agent can only sense the relative positions of its neighboring two agents that are immediately in front of or behind it. The stability of the closed-loop system is analyzed, and the performance of the proposed controller is verified through simulations.

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