scholarly journals Accurate Synchronization of Digital and Analog Chaotic Systems by Parameters Re-Identification

Electronics ◽  
2018 ◽  
Vol 7 (7) ◽  
pp. 123 ◽  
Author(s):  
Timur Karimov ◽  
Denis Butusov ◽  
Valery Andreev ◽  
Artur Karimov ◽  
Aleksandra Tutueva
Keyword(s):  
Chaotic Systems ◽  
Analog Circuit ◽  
Chaotic Oscillation ◽  
Optimization Method ◽  
Fine Tuning ◽  
Hybrid Technique ◽  
Practical Applications ◽  
Digitally Controlled ◽  
Systems Identification ◽  
Analog Systems

The verification of the digital models of chaotic systems and processes is a valuable problem in many practical applications, such as nonlinear control and communications. In our study, we propose a hybrid technique for chaotic systems’ identification, based on the chaotic synchronization of digital and analog counterparts and a numerical optimization method used for the fine tuning of parameters. An analog circuit implementing the Rössler oscillator with digitally controlled parameters was chosen as an identification object, and the FPGA model was used as a digital counterpart for coupling and parameter retrieval. The synchronization between analog and digital chaotic models can be used to estimate the quality of an identification procedure. The results of this study clarify the practical bounds of digital and analog systems’ equivalence. They also contribute to the problem of designing technical systems possessing advantages of both analog and digital chaotic generators (e.g., a high accuracy and protection from quasi-chaotic oscillation modes).

scholarly journals Adaptive Generalized Synchronization between Circuit and Computer Implementations of the Rössler System

2020 ◽  
Vol 11 (1) ◽  
pp. 81
Author(s):  
Artur Karimov ◽  
Aleksandra Tutueva ◽  
Timur Karimov ◽  
Olga Druzhina ◽  
Denis Butusov
Keyword(s):  
Computer Model ◽  
Chaotic Systems ◽  
Analog Circuit ◽  
Model Simulation ◽  
Circuit Modeling ◽  
Generalized Synchronization ◽  
Circuit Element ◽  
Practical Applications ◽  
Numerical Integration Methods ◽  
Embedded Applications

The synchronization between chaotic systems implemented in similar ways—e.g., computer models or circuits—is a well-investigated topic. Nevertheless, in many practical applications, such as communication, identification, machine sensing, etc., synchronization between chaotic systems of different implementation types—e.g., between an analog circuit and computer model—might produce fruitful results. In this research, we study the synchronization between a circuit modeling the Rössler chaotic system and a computer model using the same system. The theoretical possibility of this kind of synchronization is proved, and experimental evidence of this phenomenon is given with special attention paid to the numerical methods for computer model simulation. We show that synchronization between a circuit with uncertain parameters and a computer model is possible, and the parameters obtained from the synchronized computer model are in high correspondence with the circuit element specification. The obtained results establish the possibility of using adaptive generalized synchronization for the parameter identification of real systems. It was also found that Heun’s method yielded the most accurate results in synchronization among second-order numerical integration methods. The best among the first-order methods appears to be the Euler–Cromer method, which can be of interest in embedded applications.

scholarly journals Performance-tuning of PVA-based gel electrolytes by acid/PVA ratio and PVA molecular weight

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Saeideh Alipoori ◽  
M. M. Torkzadeh ◽  
Saeedeh Mazinani ◽  
Seyed Hamed Aboutalebi ◽  
Farhad Sharif
Keyword(s):  
Molecular Weight ◽  
Ionic Conductivity ◽  
Charge Carrier Concentration ◽  
Fine Tuning ◽  
Performance Tuning ◽  
Practical Applications ◽  
High Performing ◽  
Flexible Devices ◽  
Gel Electrolytes ◽  
Ion Conducting

AbstractThe significant breakthroughs of flexible gel electrolytes have attracted extensive attention in modern wearable electronic gadgets. The lack of all-around high-performing gels limits the advantages of such devices for practical applications. To this end, developing a multi-functional gel architecture with superior ionic conductivity while enjoying good mechanical flexibility is a bottleneck to overcome. Herein, an architecturally engineered gel, based on PVA and H3PO4 with different molecular weights of PVA for various PVA/H3PO4 ratios, was developed. The results show the dependence of ionic conductivity on molecular weight and also charge carrier concentration. Consequently, fine-tuning of PVA-based gels through a simple yet systematic and well-regulated strategy to achieve highly ion-conducting gels, with the highest ionic conductivity of 14.75 ± 1.39 mS cm-1 have been made to fulfill the requirement of flexible devices. More importantly, gel electrolytes possess good mechanical robustness while exhibiting high-elasticity (%766.66 ± 59.73), making it an appropriate candidate for flexible devices.

Optimal Synchronization of a Memristive Chaotic Circuit

2016 ◽  
Vol 26 (06) ◽  
pp. 1650093 ◽  
Author(s):  
Michaux Kountchou ◽  
Patrick Louodop ◽  
Samuel Bowong ◽  
Hilaire Fotsin ◽  
Jurgen Kurths
Keyword(s):  
Numerical Simulations ◽  
Chaos Synchronization ◽  
Chaotic Systems ◽  
Analog Circuit ◽  
Electronic Circuit ◽  
Dynamical Behavior ◽  
Circuit Implementation ◽  
Chaotic Circuit ◽  
Dynamical Properties ◽  
Analog Circuit Implementation

This paper deals with the problem of optimal synchronization of two identical memristive chaotic systems. We first study some basic dynamical properties and behaviors of a memristor oscillator with a simple topology. An electronic circuit (analog simulator) is proposed to investigate the dynamical behavior of the system. An optimal synchronization strategy based on the controllability functions method with a mixed cost functional is investigated. A finite horizon is explicitly computed such that the chaos synchronization is achieved at an established time. Numerical simulations are presented to verify the effectiveness of the proposed synchronization strategy. Pspice analog circuit implementation of the complete master-slave-controller systems is also presented to show the feasibility of the proposed scheme.

scholarly journals An Adaptive Operation Strategy for Voltage Stability Enhancement in DMFCs

2018 ◽  
Author(s):  
Qinwen Yang ◽  
Xu-Qu Hu ◽  
Ying Zhu ◽  
Xiu-Cheng Lei ◽  
Xing-Yi Wang
Keyword(s):  
Voltage Stability ◽  
Optimization Method ◽  
Operation Strategy ◽  
Practical Applications ◽  
Operating Current ◽  
Voltage Stability Enhancement ◽  
Voltage Deviation ◽  
Adaptive Operation ◽  
Underlying Mechanisms ◽  
Stability Enhancement

An adaptive operation strategy for on-demand control of DMFC system is proposed as an alternative method to enhance the voltage stability. Based on a single-cell DMFC stack, a newly simplified semi-empirical model is developed from the uniform-designed experimental results to describe the I-V relationship. Integrated with this model, the multi-objective optimization method is utilized to develop an adaptive operation strategy. Although the voltage instability is frequently encountered in unoptimized operations, the voltage deviation is successfully decreased to a required level by adaptive operations with operational adjustments. Moreover, the adaptive operations are also found to be able to extend the range of operating current density or to decrease the voltage deviation according to ones requirements. Numerical simulations are implemented to investigate the underlying mechanisms of the proposed adaptive operation strategy, and experimental adaptive operations are also performed on another DMFC system to validate the adaptive operation strategy. Preliminary experimental study shows a rapid response of DMFC system to the operational adjustment, which further validates the effectiveness and feasibility of the adaptive operation strategy in practical applications. The proposed strategy contributes to a guideline for the better control of output voltage from operating DMFC systems.

scholarly journals The State-space Model of Micro-chaos

2021 ◽  
Vol 15 ◽  
pp. 184-189
Author(s):  
Gabor Csernak ◽  
Gabor Stepan
Keyword(s):  
Chaotic Systems ◽  
Initial Conditions ◽  
State Space Model ◽  
Unstable State ◽  
Considerable Influence ◽  
Chaotic Oscillations ◽  
Controlled System ◽  
Space Model ◽  
Digitally Controlled

Micro-chaos is the phenomenon when the sampling, the delay and the round-off lead to small amplitude chaotic oscillations in a digitally controlled system. It has been proved mathematically during the last few years in a couple of simple cases that the evolving vibrations are indeed chaotic. In this study, we partially generalize these results to the case when an originally unstable state of a system is stabilized by digital feedback control. It is pointed out that this type of systems are sensitive to initial conditions and there exists a finite attracting domain in their phase-space. We also show that the oscillations, related to micro-chaos may have a considerable influence on the accuracy and settling time of the control system. The application of numerical techniques is unavoidable in the case of chaotic systems. Several possibilities are highlighted in the paper for the numerical determination of important characteristics of microchaotic oscillations.

scholarly journals Attention Optimization Method for EEG via the TGAM

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yu Wu ◽  
Ning Xie
Keyword(s):  
Optimization Method ◽  
Faculty Members ◽  
Computer Interface ◽  
Research Teams ◽  
Practical Applications ◽  
Eeg Data ◽  
Data Feedback ◽  
Data Output ◽  
The Stability ◽  
Stability And Accuracy

Since the 21st century, noninvasive brain-computer interface (BCI) has developed rapidly, and brain-computer devices have gradually moved from the laboratory to the mass market. Among them, the TGAM (ThinkGear Asic Module) and its encapsulate algorithm have been adopted by many research teams and faculty members around the world. However, due to the limited development cost, the effectiveness of the algorithm to calculate data is not satisfactory. This paper proposes an attention optimization algorithm based on the TGAM for EEG data feedback. Considering that the data output of the TGAM encapsulate algorithm fluctuates greatly, the delay is high and the accuracy is low. The experimental results demonstrated that our algorithm can optimize EEG data, so that with the same or even lower delay and without changing the encapsulate algorithm of the module itself, it can significantly improve the performance of attention data, greatly improve the stability and accuracy of data, and achieve better results in practical applications.

scholarly journals Experimental study and nonlinear dynamic analysis of time-periodic micro chaotic mixers

2007 ◽  
Vol 575 ◽  
pp. 425-448 ◽  
Author(s):  
YI-KUEN LEE ◽  
CHIANG SHIH ◽  
PATRICK TABELING ◽  
CHIH-MING HO
Keyword(s):  
Lyapunov Exponent ◽  
Nonlinear Dynamic Analysis ◽  
Main Concern ◽  
Maximum Lyapunov Exponent ◽  
Practical Applications ◽  
Flow Perturbation ◽  
Finite Time Lyapunov Exponent ◽  
Digitally Controlled ◽  
Spatio Temporal ◽  
Time Periodic

The efficiency of MEMS-based time-periodic micro chaotic mixers is experimentally and theoretically investigated in this study. A time-periodic flow perturbation was realized using digitally controlled solenoid valves to activate a source and sink alternately, acting together as a pair, with different driving frequencies. Working fluids with and without fluorescent dye were used in the micromixing experiments. The spatio-temporal variation of the mixing concentration during the mixing process was characterized at different Strouhal numbers, ranging from 0.03 to 0.74, using fluorescence microscopy. A simple kinematical model for the micromixer was used to demonstrate the presence of chaotic mixing. Specific stretching rate, Lyapunov exponent, and local bifurcation and Poincaré section analyses were used to identify the emergence of chaos. Two different numerical methods were employed to verify that the maximum Lyapunov exponent was positive in the proposed micromixer model. A simplified analytical analysis of the effect of Strouhal number is presented. Kolmogorov–Arnold–Mose (KAM) curves, which are mixing barriers, were also found in Poincaré sections. From a comparative study of the experimental results and theoretical analysis, a finite-time Lyapunov exponent (FTLE) was shown to be a more practical mixing index than the classical Lyapunov exponent because the time spent in mixing is the main concern in practical applications, such as bio-medical diagnosis. In addition, the FTLE takes into account both fluid stretching in terms of the stretching rate and fluid folding in terms of curvature.

Design Optimization of Machine-Tool Structures With Respect to Dynamic Characteristics

1983 ◽  
Vol 105 (1) ◽  
pp. 88-96 ◽  
Author(s):  
M. Yoshimura ◽  
T. Hamada ◽  
K. Yura ◽  
K. Hitomi
Keyword(s):  
Machine Tool ◽  
Design Optimization ◽  
Dynamic Characteristics ◽  
Machine Tools ◽  
Structural Model ◽  
Optimization Method ◽  
Practical Applications ◽  
Design Variables ◽  
Design Changes ◽  
Machine Tool Structures

This paper proposes a design optimization method in which simplified structural models and standard mathematical programming methods are employed in order to optimize the dynamic characteristics of machine-tool structures in practical applications. This method is composed of three phases: (1) simplification, (2) optimization, and (3) realization. As design variables employed in this optimization are greatly reduced, machine-tool structures are optimized effectively in practice. With large design changes being conducted through this multiphase procedure, dynamic characteristics of machine tools can be greatly improved. This method is demonstrated on a structural model of a vertical lathe.

An Energy-Balanced Path Plan Strategy for Mobile Sensor Networks

2015 ◽  
Vol 738-739 ◽  
pp. 65-69 ◽  
Author(s):  
Li Li Zheng ◽  
Qiu Ling Tang ◽  
Xian Li
Keyword(s):  
Energy Consumption ◽  
Travelling Salesman Problem ◽  
Optimization Method ◽  
Mobile Sink ◽  
Practical Applications ◽  
Planning Strategy ◽  
Energy Consumption Reduction ◽  
Consumption Reduction ◽  
Infinite Energy ◽  
Moving Path

Several studies have demonstrated that significant energy consumption reduction of nodes and network energy hole elimination can be achieved by introducing a mobile sink. In most related researches, mobile sink's energy is always assumed to be sufficient to collect data sensed by normal nodes. However, mobile sink consumes large amounts of energy in practical applications and it is impossible to own infinite energy. Correspondingly, the moving path plan of the mobile sink, which can be treated as a TSP (Travelling Salesman Problem), plays an important role in reducing and balancing network energy consumption. In this paper, an energy efficient mobile sink path planning strategy (EEPP) is proposed. In this strategy, LEACH protocol is introduced to balance the static network energy consumption; A heuristic path optimization method is utilized to further shorten the mobile sink path and reduce network latency. Simulation results show that our algorithm has good performance on the network energy consumption balancing, thus extending the network lifetime.

H 2, Mixed H2/H∞ and H2/L1 Optimally Tuned Passive Isolators and Absorbers

1998 ◽  
Vol 120 (2) ◽  
pp. 282-287 ◽  
Author(s):  
Wassim M. Haddad ◽  
Ali Razavi
Keyword(s):  
Frequency Response ◽  
Ad Hoc ◽  
Vibration Suppression ◽  
Peak Frequency ◽  
Optimization Method ◽  
Worst Case ◽  
Practical Applications ◽  
System Vibration ◽  
Response Performance ◽  
Optimization Schemes

In many practical applications, unbalanced rotating machinery cause vibrations that transmit large oscillatory forces to the system foundation. Using ad hoc optimization schemes tuned isolators and absorbers have traditionally been designed to suppress system vibration levels by attempting to minimize the peak frequency response of the force/displacement transmissibility system transfer function. In this paper, we formulate the classical isolator and absorber vibration suppression problems in terms of modern system theoretic criteria involving H2 (shock response), mixed H2/H∞ (worst-case peak frequency response), and mixed H2/L1 (worst-case peak amplitude response) performance measures. In particular, using a quasi-Newton optimization method we design H2, mixed H2/H∞ and mixed H2/L1 optimally tuned isolators and absorbers for multi-degree-of-freedom vibrational systems. Finally, we compare our results to the classical Snowdon and Den Hartog absorbers.

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