scholarly journals Study of “Sticking and Restarting Phenomenon” in Electropneumatic Positioning Systems

2005 ◽  
Vol 127 (1) ◽  
pp. 173-184 ◽  
Author(s):  
Xavier Brun ◽  
Sylvie Sesmat ◽  
Daniel Thomasset ◽  
Serge Scavarda
Keyword(s):  
Dry Friction ◽  
Partial Equilibrium ◽  
Experimental Result ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Pressure Force ◽  
Friction Forces ◽  
Positioning Systems ◽  
Necessary And Sufficient ◽  
Theoretical Results

This paper explains the possible occurrence of the “sticking and restarting phenomenon” observed with electropneumatic positioning systems. This is carried out from the notion of partial equilibrium, with the analysis of the model which incorporates two parallel phenomena which are used to generate a pressure force subjected to dry friction forces. Also, an experimental result has been studied in a particular pressure force plane which shows the origin of the problem more explicitly. The theoretical results give a necessary and sufficient condition for the restarting phenomenon not to occur and, if this condition is not validated, there is an estimation of the restarting time. Understanding this undesirable phenomenon will be the basis for further work which will attempt to find solutions to avoid its occurrence.

scholarly journals Synchronization of a Generalized High-dimensional Kuramoto Model With Directed Graphs

2021 ◽  
Author(s):  
Jinxing Zhang ◽  
Jiandong Zhu ◽  
Xiaodi Li
Keyword(s):  
Directed Graph ◽  
Directed Graphs ◽  
Kuramoto Model ◽  
High Dimensional ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Initial State ◽  
Necessary And Sufficient ◽  
Theoretical Results

Abstract In this paper, a generalized high-dimensional Kuramoto model with directed graphs is investigated. A necessary and sufficient condition for equilibria is given and the synchronization is proved under weaker directed graph conditions and more general initial state constrains. Finally, an example is given to validate the theoretical results.

scholarly journals Multivaluedness in Networks: Theory

2020 ◽  
Author(s):  
Anton van Wyk
Keyword(s):  
Structural Complexity ◽  
The Other ◽  
Sufficient Condition ◽  
The Novel ◽  
Necessary And Sufficient Condition ◽  
Cascaded Systems ◽  
The Right ◽  
Necessary And Sufficient ◽  
Theoretical Results

<div>An unexpected and somewhat surprising observation is that two counter-cascaded systems,12 satisfying the right conditions, implicitly exhibit multivaluedness from one of the outputs to the other. Based on the novel notions of immanence and transcendence, the main result presented here, gives a necessary and sufficient condition for multivaluedness to be exhibited by counter-cascaded systems. Subsequent corollaries provide further characterization of multivaluedness under specific conditions.</div><div><br></div><div>As an application of these theoretical results, we demonstrate how these aid in the structural complexity reduction of directed complex networks.</div>

scholarly journals Nonidentical Coupled Networks with a Geographical Model for Human Behaviors During Catastrophic Events

2017 ◽  
Vol 27 (14) ◽  
pp. 1750213 ◽  
Author(s):  
Guillaume Cantin
Keyword(s):  
Global Stability ◽  
Numerical Simulations ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Catastrophic Events ◽  
Human Behaviors ◽  
Coupled Networks ◽  
Trivial Equilibrium ◽  
Necessary And Sufficient ◽  
Theoretical Results

The purpose of this work is to study coupled networks of nonidentical instances of the PCR system (Panic-Control-Reflex), which is a geographical model for human behaviors during catastrophic events. We endow the subsequent graph with superposed linear and quadratic couplings, and explore the effect of the topology of the network on the dynamics of each node. Especially, we investigate the possibility of controlling the panic level in the network by a clever disposal of the connections. We establish a necessary and sufficient condition for synchronization, without any reductive assumption on the nature of the network, and study the global stability of the trivial equilibrium. We illustrate our theoretical results by numerical simulations of randomly generated networks.

scholarly journals Leader-Following Consensus in Networks of Agents with Nonuniform Time-Varying Delays

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Zhao-Jun Tang ◽  
Ting-Zhu Huang ◽  
Jiang-Ping Hu ◽  
Jin-Liang Shao
Keyword(s):  
Sufficient Condition ◽  
Time Varying ◽  
Consensus Problem ◽  
Communication Delays ◽  
Necessary And Sufficient Condition ◽  
Leader Following ◽  
Fixed Topology ◽  
Simulation Results ◽  
Necessary And Sufficient ◽  
Theoretical Results

This paper is concerned with a leader-following consensus problem for networks of agents with fixed and switching topologies as well as nonuniform time-varying communication delays. By employing Lyapunov-Razumikhin function, a necessary and sufficient condition is derived in the case of fixed topology, and a sufficient condition is obtained in the case when the interconnection topology is switched and satisfies certain condition. Simulation results are provided to illustrate the theoretical results.

scholarly journals H-Index for Stochastic Linear Discrete-Time Systems

2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
Yan Li ◽  
Weihai Zhang ◽  
Xikui Liu
Keyword(s):  
Discrete Time ◽  
Observer Design ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
H Index ◽  
Discrete Time Systems ◽  
Necessary And Sufficient ◽  
Index Problem ◽  
Time Systems ◽  
Theoretical Results

This paper discusses theH-index problem for stochastic linear discrete-time systems. A necessary and sufficient condition ofH-index is given for such systems in finite horizon. It is proved that when theH-index is greater than a given value, the feasibility ofH-index is equivalent to the solvability of a constrained difference equation. The above result can be applied to the fault detection observer design. Finally, some examples are presented to illustrate the proposed theoretical results.

scholarly journals Consensus Analysis of Fractional-Order Multiagent Systems with Double-Integrator

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Chunde Yang ◽  
Wenjing Li ◽  
Wei Zhu
Keyword(s):  
Multiagent Systems ◽  
Fractional Order ◽  
Spanning Tree ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Consensus Analysis ◽  
Directed Spanning Tree ◽  
Necessary And Sufficient ◽  
Theoretical Results ◽  
Double Integrator

In nature, many phenomena can be explained by coordinated behavior of agents with fractional-order dynamics. In this paper, the consensus problem of fractional-order multiagent systems with double-integrator is studied, where the fractional-order satisfies0<α<2. Based on the fractional-order stability theory, Mittag-Leffler function, and Laplace transform, a necessary and sufficient condition is obtained under the assumption that the directed graph for the communication network contains a directed spanning tree. Finally, an example with simulation is presented to illustrate the theoretical results.

Characterization of ℓ1 minimizer in one-bit compressed sensing

2019 ◽  
Vol 17 (06) ◽  
pp. 1005-1021 ◽  
Author(s):  
Ning Bi ◽  
Jun Tan
Keyword(s):  
Compressive Sensing ◽  
Information Science ◽  
Convex Sets ◽  
Sufficient Condition ◽  
Relaxation Model ◽  
Necessary And Sufficient Condition ◽  
The One ◽  
Necessary And Sufficient ◽  
Theoretical Results

The conception of one-bit compressive sensing (one-bit CS) was first introduced in 2008 by Boufounos and Baraniuk [1-Bit compressive sensing, in Proc. Conf. on Information Science and Systems (CISS, Princeton, NJ, 2008)]. Since then, many efficient algorithms have been developed for dealing with the one-bit CS problem. However, few theoretical results are available on one-bit CS. In this paper, we focus on one-bit CS theory with its relaxation model [Formula: see text] and present a necessary and sufficient condition such that the signal [Formula: see text] is the unique [Formula: see text] minimizer in noiseless one-bit CS (Theorem 3). Moreover, by using the improved separation theorem of convex sets (Theorem 6), we completely characterize the [Formula: see text] minimizer in one-bit CS (Theorem 2). Finally, as an application of Theorem 2, the [Formula: see text] minimizer for the considered model can, in general, be a non-sparse vector.

A Proposed Framework Emphasizing Auditor Reliability over Auditor Independence

2003 ◽  
Vol 17 (3) ◽  
pp. 257-266 ◽  
Author(s):  
Mark H. Taylor ◽  
F. Todd DeZoort ◽  
Edward Munn ◽  
Martha Wetterhall Thomas
Keyword(s):  
Public Interest ◽  
Auditor Independence ◽  
Public Confidence ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Accounting Profession ◽  
The Public ◽  
Necessary And Sufficient

This paper introduces an auditor reliability framework that repositions the role of auditor independence in the accounting profession. The framework is motivated in part by widespread confusion about independence and the auditing profession's continuing problems with managing independence and inspiring public confidence. We use philosophical, theoretical, and professional arguments to argue that the public interest will be best served by reprioritizing professional and ethical objectives to establish reliability in fact and appearance as the cornerstone of the profession, rather than relationship-based independence in fact and appearance. This revised framework requires three foundation elements to control subjectivity in auditors' judgments and decisions: independence, integrity, and expertise. Each element is a necessary but not sufficient condition for maximizing objectivity. Objectivity, in turn, is a necessary and sufficient condition for achieving and maintaining reliability in fact and appearance.

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