scholarly journals Modeling and Dynamics Analysis of a Universal Interface for Constructing Floating Fractional Order Mem-Elements

2021 ◽  
Author(s):  
Ya Li ◽  
Lijun Xie ◽  
Ciyan Zheng ◽  
Dongsheng Yu ◽  
Jason K. Eshraghian
Keyword(s):  
Fractional Order ◽  
Temporal Dynamics ◽  
Memory Systems ◽  
Memory Element ◽  
Frequency Responses ◽  
Fine Grain ◽  
Practical Design ◽  
Different Types ◽  
Universal Interface ◽  
Memory Characteristics

Abstract Fractional-order systems generalize classical differential systems and have empirically shown to achieve fine-grain modeling of the temporal dynamics and frequency responses of certain real-world phenomena. Although the study of integer-order memory element (mem-element) emulators has persisted for several years, the study of fractional-order memory elements (FOMEs) has received little attention. To promote the study of the characteristics and applications of mem-element systems in fractional calculus (FC) and memory systems, in this paper, we propose a novel universal interface for constructing floating FOMEs. When the topological structure of the interface remains unchanged, the floating fractional-order memristor (FOMR), fractional-order memcapacitor (FOMC) and fractional-order meminductor (FOMI) emulators can be realized by using the impedance combinations of different passive elements, without any mem-element emulators and mutators. When compared with previously proposed FOMEs, the proposed fractional-order mem-element emulators based on a universal interface not only feature the characteristics of floating terminals and simpler circuit structures, but can also realize all three different types of FOMEs. To explore the dynamical relationships between the mem-elements and the fractional order, we mathematically derive and analyze the maximum and minimum possible values of memductance, memcapacitance and inverse meminductance which accounts for practical design considerations when building FO systems. The memory characteristics of FOMEs are analyzed by varying their orders and stimuli frequencies. The consistency of theoretical analysis, numerical calculation and simulation results validates the correctness of our proposed emulators.

Comparison of two different types of fractional-order COVID-19 distributed time-delay models with real data application

2021 ◽  
pp. 2150219
Author(s):  
Liangli Yang ◽  
Yongmei Su ◽  
Xinjian Zhuo
Keyword(s):  
Time Delay ◽  
Fractional Order ◽  
Distributed Delay ◽  
Real Data ◽  
Least Square ◽  
Order Model ◽  
The Real ◽  
Fractional Order Model ◽  
Different Types ◽  
Distributed Time Delay

The outbreak of COVID-19 has a great impact on the world. Considering that there are different infection delays among different populations, which can be expressed as distributed delay, and the distributed time-delay is rarely used in fractional-order model to simulate the real data, here we establish two different types of fractional order (Caputo and Caputo–Fabrizio) COVID-19 models with distributed time-delay. Parameters are estimated by the least-square method according to the report data of China and other 12 countries. The results of Caputo and Caputo–Fabrizio model with distributed time-delay and without delay, the integer-order model with distributed delay are compared. These show that the fractional-order model can be better in fitting the real data. Moreover, Caputo order is better in short-term time fitting, Caputo–Fabrizio order is better in long-term fitting and prediction. Finally, the influence of several parameters is simulated in Caputo order model, which further verifies the importance of taking strict quarantine measures and paying close attention to the incubation period population.

scholarly journals Performance Evaluation of Fractional Order Pid and Sliding Mode Control with Optimization Tuning Access

2019 ◽  
Vol 8 (2S8) ◽  
pp. 1448-1454
Keyword(s):  
Fractional Order ◽  
Pid Controller ◽  
World Economy ◽  
Sliding Mode ◽  
Proportional Integral Derivative ◽  
Robust Controller ◽  
The Past ◽  
Control Schemes ◽  
Different Types ◽  
Fractional Order Pid

The statistical analyses in the past showing the important properties of the electrohydraulic actuator (EHA) system, especially in the growth of the world economy. Dealing with the existing drawback in the EHA system, various types of control schemes have been introduced in the past. In this paper, to produce a more insightful view of the performance and the capabilities of the controller, three different types of controllers have been designed and compared. The favourite controller in the industry field, which is the proportional-integral-derivative (PID) controller will be first introduced. Follow by the improved PID controller, named Fractional Order (FO-PID) controller will be designed. Then, the prominent robust controller in the control field, called sliding mode controller (SMC) will be established. Instead of obtaining the controller’s parameters without any appropriate technique, the well-known tuning technique in computer science, named particle swarm optimization (PSO) will be utilized. Referring to the performances produced by these controllers, it can be concluded that the SMC is capable to generate most desired control performance that produced the highest accuracy with the smallest error in the analyses.

scholarly journals Stability of Fractional Order Systems

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Margarita Rivero ◽  
Sergei V. Rogosin ◽  
José A. Tenreiro Machado ◽  
Juan J. Trujillo
Keyword(s):  
Fractional Calculus ◽  
Fractional Order ◽  
State Of The Art ◽  
Point Of View ◽  
Fractional Order Systems ◽  
Short Period ◽  
Systems And Control ◽  
Different Types ◽  
The Stability ◽  
And Control

The theory and applications of fractional calculus (FC) had a considerable progress during the last years. Dynamical systems and control are one of the most active areas, and several authors focused on the stability of fractional order systems. Nevertheless, due to the multitude of efforts in a short period of time, contributions are scattered along the literature, and it becomes difficult for researchers to have a complete and systematic picture of the present day knowledge. This paper is an attempt to overcome this situation by reviewing the state of the art and putting this topic in a systematic form. While the problem is formulated with rigour, from the mathematical point of view, the exposition intends to be easy to read by the applied researchers. Different types of systems are considered, namely, linear/nonlinear, positive, with delay, distributed, and continuous/discrete. Several possible routes of future progress that emerge are also tackled.

Practical Design and Evaluation of Fractional-Order Oscillator Using Differential Voltage Current Conveyors

2016 ◽  
Vol 35 (6) ◽  
pp. 2003-2016 ◽  
Author(s):  
David Kubánek ◽  
Fabian Khateb ◽  
Georgia Tsirimokou ◽  
Costas Psychalinos
Keyword(s):  
Fractional Order ◽  
Current Conveyors ◽  
Differential Voltage ◽  
Practical Design

scholarly journals F3SNet: A Four-Step Strategy for QIM Steganalysis of Compressed Speech Based on Hierarchical Attention Network

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Chuanpeng Guo ◽  
Wei Yang ◽  
Mengxia Shuai ◽  
Liusheng Huang
Keyword(s):  
Linear Prediction ◽  
State Of The Art ◽  
Communication Security ◽  
Great Success ◽  
Attention Network ◽  
Compressed Speech ◽  
Different Types ◽  
Comprehensive Comparison ◽  
Embedding Rate ◽  
Memory Characteristics

Traditional machine learning-based steganalysis methods on compressed speech have achieved great success in the field of communication security. However, previous studies lacked mathematical modeling of the correlation between codewords, and there is still room for improvement in steganalysis for small-sized and low embedding rate samples. To deal with the challenge, we use Bayesian networks to measure different types of correlations between codewords in linear prediction code and present F3SNet—a four-step strategy: embedding, encoding, attention, and classification for quantization index modulation steganalysis of compressed speech based on the hierarchical attention network. Among them, embedding converts codewords into high-density numerical vectors, encoding uses the memory characteristics of LSTM to retain more information by distributing it among all its vectors, and attention further determines which vectors have a greater impact on the final classification result. To evaluate the performance of F3SNet, we make a comprehensive comparison of F3SNet with existing steganography methods. Experimental results show that F3SNet surpasses the state-of-the-art methods, particularly for small-sized and low embedding rate samples.

Hidden Chaotic Attractors and Synchronization for a New Fractional-Order Chaotic System

2019 ◽  
Vol 14 (8) ◽  
Author(s):  
Zuoxun Wang ◽  
Jiaxun Liu ◽  
Fangfang Zhang ◽  
Sen Leng
Keyword(s):  
Fractional Order ◽  
Chaotic System ◽  
Finite Time ◽  
Chaotic Systems ◽  
Time Synchronization ◽  
Chaotic Attractors ◽  
Finite Time Stability ◽  
Integer Order ◽  
Different Types ◽  
Synchronization Scheme

Although a large number of hidden chaotic attractors have been studied in recent years, most studies only refer to integer-order chaotic systems and neglect the relationships among chaotic attractors. In this paper, we first extend LE1 of sprott from integer-order chaotic systems to fractional-order chaotic systems, and we add two constant controllers which could produce a novel fractional-order chaotic system with hidden chaotic attractors. Second, we discuss its complicated dynamic characteristics with the help of projection pictures and bifurcation diagrams. The new fractional-order chaotic system can exhibit self-excited attractor and three different types of hidden attractors. Moreover, based on fractional-order finite time stability theory, we design finite time synchronization scheme of this new system. And combination synchronization of three fractional-order chaotic systems with hidden chaotic attractors is also derived. Finally, numerical simulations demonstrate the effectiveness of the proposed synchronization methods.

The Effect of Bath Ph on the Phase Formation of Ternary Co-Ni-Fe Nano-Coatings

2013 ◽  
Vol 391 ◽  
pp. 9-13 ◽  
Author(s):  
Nor Azrina Resali ◽  
Koay Mei Hyie ◽  
Wan Normimi Roslini Abdullah ◽  
M.A.A. Ghani ◽  
A. Kalam
Keyword(s):  
Phase Formation ◽  
Deposition Time ◽  
Ph Value ◽  
Grain Morphology ◽  
Xrd Analysis ◽  
Properties Of Coatings ◽  
Plating Bath ◽  
Fine Grain ◽  
Different Types ◽  
Main Factor

This study describes how the control of bath pH allows different types of phase formation in the ternary Co-Ni-Fe nanocoating. The acidity of the plating bath has been known as a main factor to the properties of coatings. The Co-Ni-Fe coating was fabricated using a commercial electrodepostion process. Several pH solutions (3, 7 and 9) were employed to determine the optimum condition for Co-Ni-Fe synthesis. The bath pH was varied by using sodium hydroxide (NaOH) and sulphuric acid (H2SO4). Other parameters such as temperature, electrolyte composition, deposition time and current density were kept constant. The experiment was performed at 50°C. This temperature is commonly used in the industrial plating process. XRD analysis indicated the presence of both phases: body centred cubic (BCC) and face centred cubic (FCC) dependent on the pH value. Co-Ni-Fe nanocoatings obtained from the electrolyte of low pH showed the fine-grain morphology. The hardness of the Co-Ni-Fe nanocoatings was closely related to the obtained morphology.

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