On the practical h-stabilization of nonlinear time-varying systems: application to separately excited DC motor

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hanen Damak ◽  
Mohamed Ali Hammami ◽  
Abir Kicha
Keyword(s):  
Control Systems ◽  
Design Methodology ◽  
Dc Motor ◽  
Lyapunov Theory ◽  
Fundamental Result ◽  
Nonlinear Control Systems ◽  
Time Varying ◽  
Content Type ◽  
Time Varying Systems ◽  
Lyapunov Second Method

Purpose The purpose of this paper is to report on the global practical uniform h-stabilization for certain classes of nonlinear time-varying systems and its application in a separately excited DC motor circuit. Design/methodology/approach Based on Lyapunov theory, the practical h-stabilization result is derived to guarantee practical h-stability and applicated in a separately excited DC motor. Findings A controller is designed and added to the nonlinear time-varying system. The practical h-stability of the nonlinear control systems is guaranteed by applying the appropriate controller based on Lyapunov second method. Another effective controller is also designed for the global practical uniform h-stability on the separately excited DC motor with load. Numerical simulations are demonstrated to verify the effectiveness of the proposed controller scheme. Originality/value The introduced approach is interesting for practical h-stabilization of nonlinear time-varying systems and its application in a separately excited DC motor. The original results generalize well-known fundamental result: practical exponential stabilization for nonlinear time-varying systems.

Take-off control and characteristics of FanWing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lin Meng ◽  
Yang Gao ◽  
Yangyang Liu ◽  
Shengfang Lu
Keyword(s):  
Control System ◽  
Control Systems ◽  
Design Methodology ◽  
Control System Design ◽  
Control Methods ◽  
Force Analysis ◽  
Close Attention ◽  
Content Type ◽  
Vehicle Load ◽  
Practical Implications

Purpose As a short take-off and landing aircraft, FanWing has the capability of being driven under power a short distance from a parking space to the take-off area. The purpose of this paper is to design the take-off control system of FanWing and study the factors that influence the short take-off performance under control. Design/methodology/approach The force analysis of FanWing is studied in the take-off phase. Two take-off control methods are researched, and several factors that influence the short take-off performance are studied under control. Findings The elevator and fan wing control systems are designed. Although the vehicle load increases under the fan wing control, the fan wing control is not a recommended practice in the take-off phase for its sensitivity to the pitch angle command. The additional pitch-down moment has a significant influence on the control system and the short take-off performance that the barycenter variation of FanWing should be considered carefully. Practical implications The presented efforts provide a reference for the location of the center of gravity in designing FanWing. The traditional elevator control is more recommended than the fan wing control in the take-off phase. Originality/value This paper offers a valuable reference on the control system design of FanWing. It also proves that there is an additional pith-down moment that needs to be paid close attention to. Four factors that influence the short take-off performance are compared under control.

scholarly journals Volatility clustering in land markets

2014 ◽  
Vol 32 (5) ◽  
pp. 378-385 ◽  
Author(s):  
Helen Xiaohui Bao ◽  
Helen Hui Huang ◽  
Yu-Lieh Huang ◽  
Pin-te Lin
Keyword(s):  
Economic Theory ◽  
Portfolio Management ◽  
Government Policy ◽  
Design Methodology ◽  
Land Markets ◽  
Time Varying ◽  
Content Type ◽  
Volatility Clustering ◽  
Systematic Pattern ◽  
Empirical Approaches

Purpose – The purpose of this paper is to investigate the volatility clustering in the return of land markets through both theoretical and empirical approaches. Design/methodology/approach – Using extensive monthly panel data at the provincial level from 1986 to 2013, the authors identify the existence of time-correlated and time-varying returns in Canadian land markets. Findings – Consistent with the proposed theory, volatility clustering in land markets tends to be observed in more populated areas. Originality/value – The result has significant implications for portfolio management, economic theory and government policy by revealing the systematic pattern of volatility clustering in land markets.

Effects of ethical leadership and formal control systems on employee opportunistic behavior in China

2018 ◽  
Vol 25 (5) ◽  
pp. 1350-1362 ◽  
Author(s):  
Changsuk Ko ◽  
Mark H. Haney ◽  
Gukseong Lee
Keyword(s):  
Regression Analysis ◽  
Control Systems ◽  
Ethical Leadership ◽  
Interaction Effect ◽  
Design Methodology ◽  
Opportunistic Behavior ◽  
Direct Effects ◽  
Content Type ◽  
Formal Control ◽  
The Relationship

PurposeThe purpose of this paper is to explore how ethical leadership and formal control systems influence employee opportunistic behavior.Design/methodology/approachUsing survey data collected from Chinese employees (N=430), the authors conducted regression analysis to test hypothesized relationships between ethical leadership and formal control systems and employee opportunistic behavior. Both direct effects and an interaction effect were tested.FindingsThe authors found that both ethical leadership and formal control systems individually play significant roles in reducing employee opportunistic behavior. In addition, the results indicate that ethical leadership and formal control systems function as complements to jointly constrain employee opportunistic behaviors.Originality/valueThis study contributes to an understanding of the relationship between supervisors and followers in China by demonstrating the effects of ethical leadership and formal control systems on employee opportunistic behaviors, including an interesting interaction effect.

scholarly journals Construction of China’s financial conditions index in the post-crisis era

2019 ◽  
Vol 2 (2) ◽  
pp. 258-276
Author(s):  
Nan Li ◽  
Liu Yuanchun
Keyword(s):  
Financial Stability ◽  
Design Methodology ◽  
Predictive Power ◽  
Time Varying ◽  
Content Type ◽  
Vector Autoregressive ◽  
Financial Variables ◽  
Financial Conditions ◽  
Time Varying Parameter ◽  
Better Than

Purpose The purpose of this paper is to summarize different methods of constructing the financial conditions index (FCI) and analyze current studies on constructing FCI for China. Due to shifts of China’s financial mechanisms in the post-crisis era, conventional ways of FCI construction have their limitations. Design/methodology/approach The paper suggests improvements in two aspects, i.e. using time-varying weights and introducing non-financial variables. In the empirical study, the author first develops an FCI with fixed weights for comparison, constructs a post-crisis FCI based on time-varying parameter vector autoregressive model and finally examines the FCI with time-varying weights concerning its explanatory and predictive power for inflation. Findings Results suggest that the FCI with time-varying weights performs better than one with fixed weights and the former better reflects China’s financial conditions. Furthermore, introduction of credit availability improves the FCI. Originality/value FCI constructed in this paper goes ahead of inflation by about 11 months, and it has strong explanatory and predictive power for inflation. Constructing an appropriate FCI is important for improving the effectiveness and predictive power of the post-crisis monetary policy and foe achieving both economic and financial stability.

Observed effectiveness of the COSO 2013 framework

2019 ◽  
Vol 16 (1) ◽  
pp. 31-45
Author(s):  
Ifeoma Udeh
Keyword(s):  
Control Systems ◽  
Internal Control ◽  
Design Methodology ◽  
Control Process ◽  
Regression Analyses ◽  
Section 404 ◽  
Content Type ◽  
Sarbanes Oxley ◽  
Material Weaknesses ◽  
Practical Implications

Purpose This paper aims to examine the effectiveness of the Committee of Sponsoring Organization’s 2013 Framework, by investigating how the number of auditor-reported material weaknesses compares for Early-, Timely- and Late-adopters of the framework, and how the number of auditor-reported material weaknesses changed for Early- and Timely-adopters following their adoption of the framework. Design/methodology/approach The paper uses regression analyses based on a sample of US firms subject to Sarbanes-Oxley Act Section 404(b). Findings Timely-adopters of the 2013 Framework continued to exhibit fewer instances of auditor-reported material weaknesses than Late-adopters, even though they had a marginal increase in the number of auditor-reported material weaknesses, in the post-2013 Framework period. Practical implications The findings suggest that the effectiveness of the 2013 Framework may lie in the iterative nature of the internal control process, and as firms remedy deficiencies they or their auditors identify, they will continuously improve the effectiveness of their internal control systems. Originality/value Unlike existing literature, this paper uses data from the pre-2013 Framework, transition and post-2013 Framework periods to examine changes in the number of auditor-reported material weaknesses, thus differentiating between Early-, Timely- and Late-adopters of the 2013 Framework. It also shows the effect of adopting the 2013 Framework on the number of auditor-reported material weaknesses.

Discrete Verhulst model based on a linear time-varying

2014 ◽  
Vol 4 (2) ◽  
pp. 299-310 ◽  
Author(s):  
Xia Long ◽  
Yong Wei ◽  
Zhao Long
Keyword(s):  
Differential Equations ◽  
Difference Equations ◽  
Design Methodology ◽  
Linear Time ◽  
Original Data ◽  
Time Varying ◽  
Sequential Simulation ◽  
Content Type ◽  
Verhulst Model ◽  
Practical Implications

Purpose – The purpose of this paper is to build a linear time-varying discrete Verhulst model (LTDVM), to realise the convert from continuous forms to discrete forms, and to eliminate traditional grey Verhulst model's error caused by difference equations directly jumping to differential equations. Design/methodology/approach – The methodology of the paper is by the light of discrete thoughts and countdown to the original data sequence. Findings – The research of this model manifests that LTDVM is unbiased on the “s” sequential simulation. Practical implications – The example analysis shows that LTDVM embodies simulation and prediction with high precision. Originality/value – This paper is to realise the convert from continuous forms to discrete forms, and to eliminate traditional grey Verhulst model's error caused by difference equations directly jumping to differential equations. Meanwhile, the research of this model manifests that LTDVM is unbiased on the “s” sequential simulation.

Controls amid the chaos

2017 ◽  
Vol 33 (4) ◽  
pp. 13-15
Keyword(s):  
Control Systems ◽  
Design Methodology ◽  
Reading Time ◽  
Management Control ◽  
Management Control Systems ◽  
Content Type ◽  
Digital Revolution ◽  
Time Dynamics ◽  
Pertinent Information ◽  
Practical Implications

Purpose This paper aims to review the latest management developments across the globe and pinpoint practical implications from cutting-edge research and case studies. Design/methodology/approach This briefing is prepared by an independent writer who adds their own impartial comments and places the articles in context. Findings Evolving industries, the digital revolution and the effect of the global economic crisis has entailed huge challenges for those seeking to implement management control systems. In her article “Organizations with changing structures: how to control?” (2016), author Eva Lechner pulls aside the curtains on a festival organizer and shows that while its time dynamics and culture are very different to most industries, the need for controls still apply, and they can be successfully applied as long as keen attention is paid to their consequences. Practical implications The paper provides strategic insights and practical thinking that have influenced some of the world’s leading organizations. Originality/value The briefing saves busy executives and researchers hours of reading time by selecting only the very best, most pertinent information and presenting it in a condensed and easy-to-digest format.

Non-fragile robust H∞ control of nonlinear networked control systems with time-varying delay and unknown actuator failures

2016 ◽  
Vol 9 (3) ◽  
pp. 298-312 ◽  
Author(s):  
Yueming Zhi ◽  
Shun Jiang ◽  
Feng Pan
Keyword(s):  
Control Systems ◽  
Networked Control Systems ◽  
Networked Control ◽  
Upper And Lower Bounds ◽  
Time Varying ◽  
Content Type ◽  
Time Varying Delay ◽  
Actuator Failures ◽  
Nonlinear Networked Control Systems ◽  
Varying Delay

Purpose This paper is concerned with non-fragile robust H∞ control problems for nonlinear networked control systems (NCSs) with time-varying delay and unknown actuator failures. The paper aims to discuss these issues. Design/methodology/approach The system parameters are allowed to have time-varying uncertainties and the actuator faults are unknown but whose upper and lower bounds are known. By using some lemmas, uncertainties can be replaces with the known values. By taking the exogenous disturbance and network transmission delay into consideration, a delay nonlinear system model is constructed. Findings Based on Lyapunov stability theory, linear matrix inequalities (LMIs) and free weighting matrix methods, the sufficient conditions for the existence of the non-fragile robust H∞ controller gain are derived and which can obtained by solving the LMIs. Finally, a numerical example is provided to illustrate the effectiveness of the proposed methods. Originality/value The introduced approach is interesting for NCSs with time-varying delay and unknown actuator failures.

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