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An Effective Runge-Kutta Optimizer Based on Adaptive Population Size and Search Step Size

Computers, Materials & Continua 2023年第9期76卷 3443-3464页

作者： ala kana Imtiaz Ahmad Department of Computer Engineering College of Engineering and PetroleumKuwait UniversityKuwait CityKuwait

A newly proposed competent population-based optimization algorithm called RUN,which uses the principle of slope variations calculated by applying the Runge Kutta method as the key search mechanism,has gained wider interest in solving optimization ***,in high-dimensional problems,the search capabilities,convergence speed,and runtime of RUN *** work aims at filling this gap by proposing an improved variant of the RUN algorithm called the *** size plays a vital role in both runtime efficiency and optimization effectiveness of metaheuristic *** the original RUN where population size is fixed throughout the search process,Adaptive-RUN automatically adjusts population size according to two population size adaptation techniques,which are linear staircase reduction and iterative halving,during the search process to achieve a good balance between exploration and exploitation *** addition,the proposed methodology employs an adaptive search step size technique to determine a better solution in the early stages of evolution to improve the solution quality,fitness,and convergence speed of the original ***-RUN performance is analyzed over 23 IEEE CEC-2017 benchmark functions for two cases,where the first one applies linear staircase reduction with adaptive search step size(LSRUN),and the second one applies iterative halving with adaptive search step size(HRUN),with the original *** promote green computing,the carbon footprint metric is included in the performance evaluation in addition to runtime and *** results based on the Friedman andWilcoxon tests revealed that Adaptive-RUN can produce high-quality solutions with lower runtime and carbon footprint values as compared to the original RUN and three recent ***,with its higher computation efficiency,Adaptive-RUN is a much more favorable choice as compared to RUN in time stringent applications.

关键词： Optimization Runge Kutta(RUN) metaheuristic algorithm exploration exploitation population size adaptation adaptive search step size

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Improvements of cohesive zone model on artificial compliance and discontinuous force

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Acta Mechanica Sinica 2024年第9期40卷 47-67页

作者： ala Tabiei Li Meng Department of Mechanical and Materials Engineering University of CincinnatiCincinnati OH 45221-0070USA

The cohesive zone model(CZM)has been used widely and successfully in fracture propagation,but some basic problems are still to be *** this paper,artificial compliance and discontinuous force in CZM are ***,theories about the cohesive element(local coordinate system,stiffness matrix,and internal nodal force)are *** local coordinate system is defined to obtain local separation;the stiffness matrix for an eight-node cohesive element is derived from the calculation of strain energy;internal nodal force between the cohesive element and bulk element is obtained from the principle of virtual ***,the reason for artificial compliance is explained by the effective stiffnesses of zero-thickness and finite-thickness cohesive *** on the effective stiffness,artificial compliance can be completely removed by adjusting the stiffness of the finite-thickness cohesive *** conclusion is verified from 1D and 3D ***,three damage evolution methods(monotonically increasing effective separation,damage factor,and both effective separation and damage factor)are *** constant unloading and reloading conditions,the monotonically increasing damage factor method without discontinuous force and healing effect is a better choice than the other two *** proposed improvements are coded in LS-DYNA user-defined material,and a drop weight tear test verifies the improvements.

关键词： Cohesive zone model Stiffness matrix Artificial compliance Damage evolution method Discontinuous force

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Robust Leader-Following Output Regulation of Uncertain Multi-Agent Systems With Time-Varying Delay

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IEEE/CAA Journal of Automatica Sinica 2018年第4期5卷 807-817页

作者： ala Shariati Qing Zhao Automation&Control Research Group Faculty of Electrical and Computer EngineeringKhajeh Nasir Toosi University of TechnologyTehran ***Iran Department of Electrical and Computer Engineering at University of Alberta EdmontonAlberta T6R1Z6Canada

In this paper, the robust analysis and design of leader-following output regulation for multi-agent systems described by general linear models is given in presence of timevarying delay and model uncertainty. To this aim, a new regulation protocol for the closed-loop multi-agent system under a directed graph is proposed. An important specification of the proposed protocol is to guarantee the leader-following output regulation for uncertain multi-agent systems with both stable and unstable agents. Since many signals can be approximated by a combination of the stationary and ramp signals, the presented results work for adequate variety of the leaders. The analysis and design conditions are presented in terms of certain matrix inequalities. The method proposed can be used for both stationary and ramp leaders. Simulation results are presented to show the effectiveness of the proposed method.

关键词： Linear matrix inequality(LMI) multi-agent systems robust leader-following output regulation time-varying delay

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DNA Sequence Analysis for Brain Disorder Using Deep Learning and Secure Storage

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Computers, Materials & Continua 2022年第6期71卷 5949-5962页

作者： ala Saleh Alluhaidan Departmemt of Information Systems College of Computer and Information SciencePrincess Nourah Bint Abdulrahman UniversityRiyadh 11671Saudi Arabia

Analysis of brain disorder in the neuroimaging of Magnetic Resonance Imaging(MRI),Positron Emission Tomography(PET),and Computed Tomography(CT)needs to understand the functionalities of the brain and it has been performed using *** learning algorithms have also been applied in genomics data *** brain disorder diseases of Alzheimer,Schizophrenia,and Parkinson are analyzed in this *** main issue in the traditional algorithm is the improper detection of disorders in the neuroimaging *** paper presents a deep learning algorithm for the classification of brain disorder using Deep Belief Network(DBN)and securely storing the image using a Deoxyribonucleic Acid(DNA)Sequence-based Joint Photographic Experts Group(JPEG)Zig Zag Encryption Algorithm(DBNJZZ).In this work,DBNJZZ implements an efficient and effective prediction model for disorders using the open-access datasets of Alzheimer’s Disease Neuroimaging Initiative(Adni),the Center for Biomedical Research Excellence(Cobre),the Open Access Series of Imaging Studies(Oasis),the Function Biomedical Informatics Research Network(Fbirn),a Parkinson’s dataset of 55 patients and 23 subjects with Parkinson’s syndromes(Ntua),and the Parkinson’s Progression Markers Initiative(Ppmi).This algorithm is implemented and tested using performance metric measures of accuracy,Root Mean Square Error(RMSE),Mean Absolute Error(MAE),and Mean Absolute Percentage Error(MAPE).DBNJZZ gives better performance with an accuracy of 99.21%and also surpasses previous methods on other measures.

关键词： DBN Zig zag deep learning MAPE RMSE DNA genomics

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Linear and Nonlinear Formulation of Phase Field Model with Generalized Polynomial Degradation Functions for Brittle Fractures

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Acta Mechanica Solida Sinica 2024年第5期37卷 643-661页

作者： ala Tabiei Li Meng Department of Mechanical and Materials Engineering University of CincinnatiCincinnatiOH45221-0070USA

The classical phase field model has wide applications for brittle materials,but nonlinearity and inelasticity are found in its stress-strain *** degradation function in the classical phase field model makes it a linear formulation of phase field and computationally attractive,but stiffness reduction happens even at low *** this paper,generalized polynomial degradation functions are investigated to solve this *** first derivative of degradation function at zero phase is added as an extra constraint,which renders higher-order polynomial degradation function and nonlinear formulation of phase *** with other degradation functions(like algebraic fraction function,exponential function,and trigonometric function),this polynomial degradation function enables phase in[0,1](should still avoid the first derivative of degradation function at zero phase to be 0),so there is noconvergence *** good and meaningful finding is that,under the same fracture strength,the proposed phase field model has a larger length scale,which means larger element size and better computational *** proposed phase field model is implemented in LS-DYNA user-defined element and user-defined material and solved by the Newton-Raphson method.A tensile test shows that the first derivative of degradation function at zero phase does impact stress-strain *** I,mode II,and mixed-mode examples show the feasibility of the proposed phase field model in simulating brittle fracture.

关键词： Nonlinear formulation Generalized polynomial degradation function Brittle materials Stress-strain curve convergence

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Non-Monotonic Lyapunov-Krasovskii Functional Approach to Stability Analysis and Stabilization of Discrete Time-Delay Systems

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IEEE/CAA Journal of Automatica Sinica 2020年第3期7卷 752-763页

作者： Younes Solgi Alireza Fatehi ala Shariati Advanced Process Automation and Control Research Group Industrial Control Center of ExcellenceFaculty of Electrical EngineeringK.N.Toosi University of TechnologyTehran 16317-14191Iran IEEE

In this paper, a novel non-monotonic Lyapunov-Krasovskii functional approach is proposed to deal with the stability analysis and stabilization problem of linear discrete time-delay systems. This technique is utilized to relax the monotonic requirement of the Lyapunov-Krasovskii theorem. In this regard, the Lyapunov-Krasovskii functional is allowed to increase in a few steps, while being forced to be overall decreasing. As a result, it relays on a larger class of Lyapunov-Krasovskii functionals to provide stability of a state-delay system. To this end, using the non-monotonic Lyapunov-Krasovskii theorem, new sufficient conditions are derived regarding linear matrix inequalities(LMIs)to study the global asymptotic stability of state-delay ***, new stabilization conditions are also proposed for time-delay systems in this article. Both simulation and experimental results on a p H neutralizing process are provided to demonstrate the efficacy of the proposed method.

关键词： Linear matrix inequality(LMI) non-monotonic Lyapunov-Krasovskii functional(NMLKF) pH neutralization plant stabilization state-delay system time-delay system

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A numerical implementation of the length-scale independent phase field method

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Acta Mechanica Sinica 2021年第1期37卷 92-104,I0003页

作者： Wenlong Zhang ala Tabiei Donald French Department of Civil Engineering University of CincinnatiCincinnatiOH45220USA Department of Mathematics University of CincinnatiCincinnatiOH45220USA

The phase field method for fracture integrates the Griffith theory and damage mechanics approach to predict crack initiation and propagation within one *** replaced the discrete representation of crack by diffusive damage and solved it based on a minimization of the global energy storage *** a result,no crack tracking topology is needed,and complex crack shapes can be captures without user ***,it is also reported to have an inconsistency between the predicted fracture toughness and the material ***,a novel energetic degradation function was proposed in literature to handle this *** research does some further modifications to the global energy storage functional so that Newton's method can be directly used to solve the energy *** the new energy form,direct implementation of the length-scale independent phase field method into finite element packages like LS-DYNA becomes *** paper presents the framework and details of implementing the length-scale independent phase field method into LS-DYNA through a user-defined element and material *** numerical examples are presented to compare with the experiment crack *** importantly,this paper is one of the first ones to quantitatively predict accurate force response compared to *** examples verify the accuracy of the new energy form and implementation.

关键词： Phase field method Length-scale independency Newton’s method LS-DYNA

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A 3-D Visco-Hyperelastic Constitutive Model for Rubber with Damage for Finite Element Simulation

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Computer Modeling in Engineering & Sciences 2015年第5期105卷 25-45页

作者： ala Tabiei Suraush Khambati School of Advance Structures College of Engineering and Applied SciencesUniversity of CincinnatiOH 45221-0071USA

A constitutive model to describe the behavior of rubber from low to high strain rates is *** loading,the primary hyperelastic behavior is characterized by the six parameter Ogden’s strain-energy potential of the third *** rate-dependence is captured by the nonlinear second order BKZ model using another five parameters,having two relaxation *** unloading,a single parameter model has been presented to define Hysteresis or continuous damage,while Ogden’s two term model has been used to capture Mullin’s effect or discontinuous ***,the Feng-Hallquist failure surface dictates the ultimate failure for element *** proposed model can accurately predict the response of rubber using a limited set of experimental *** model has been validated here for the case of rubber but can be extended to a wide range of polymers.

关键词： hyperelasticity viscoelasticity hysteresis Mullin’s effect rubber constitutive

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Novel Non-monotonic Lyapunov-Krasovskii Based Stability Analysis and Stabilization of Discrete State-delay System

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International Journal of Automation and computing 2020年第5期17卷 713-732页

作者： Younes Solgi Alireza Fatehi ala Shariati APAC Research Group Industrial Control Center of ExcellenceFaculty of Electrical EngineeringK.N.Toosi University of TechnologyTehran ***Iran

This paper proposes a novel less-conservative non-monotonic Lyapunov-Krasovskii stability approach for stability analysis of discrete time-delay *** this method,monotonically decreasing requirements of the Lyapunov-Krasovskii method are replaced with non-monotonic *** Lyapunov-Krasovskii functional is allowed to increase in some steps,but the overall trend should be *** model of practical systems used for stability analysis usually contain ***,firstly a non-monotonic stability condition is derived for certain discrete time-delay systems,then robust non-monotonic stability conditions are proposed for uncertain ***,a novel stabilization algorithm is derived based on the introduced non-monotonic stability *** Lyapunov-Krasovskii functional and the controller are obtained by solving a set of linear matrix inequalities(LMI)or iterative LMI based nonlinear *** proposed theorems are first evaluated by some numerical examples,and then by simulation and implementation on the pH neutralizing process plant.

关键词： Lyapunov-Krasovskii functional discrete state-delay systems non-monotonic Lyapunov function robust stability stabilization

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AC Conductivity and Dielectric Relaxation Behavior of Sol-gel Ba_xSr_(1-x)TiO_3 Thin Films

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Journal of Materials Science & Technology 2011年第9期27卷 802-808页

作者： ala eddin A. Saif P. Poopalan Microfabrication Cleanroom School of Microelectronic Engineering University Malaysia Perlis (UniMAP)

BaxSr1-xTiO3 sol-gel thin films with x--0.5, 0.7 and 0.8 have been fabricated as AI/BST/Pt capacitor. The AC conductivity and dielectric properties over a frequency rang of 10 Hz and I MHz have been studied in order to explore the ion dynamics and relaxation mechanisms in the films. The frequency dependent conductivity plots show three regions of conduction processes. Dielectric results show that ε＇ at low frequencies increases as Sr content decreases, whereas at high frequencies, it shows opposite variation, which is attributed to the dipole dynamics. The electric modulus plots reveal the relaxation peaks which are not observed in the ε＂ plots and the contribution of the grains, grain boundaries and electrode to the relaxation mechanisms.

关键词： Barium strontium titanate (BST) thin film AC conductivity Dielectric relaxation Electric modulus

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