24 results on '"Sadek, Ibrahim"'
Search Results
2. IoT-based emergency cardiac death risk rescue alert system
- Author
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Rehman, Shafiq Ul, Sadek, Ibrahim, Huang, Binhua, Manickam, Selvakumar, and Mahmoud, Lamees N.
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- 2024
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3. Optimal scanning control of flexible structures in two-dimensional space
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Sadek, Ibrahim, Abdul-Hamid, Husein, and Scott, Julie
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- 2009
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4. Multimodal machine learning approach for emotion recognition using physiological signals.
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A. Ramadan, Mohamad, Salem, Nancy M., Mahmoud, Lamees N., and Sadek, Ibrahim
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[Display omitted] • Determining whether the multimodality approach can help improve emotion recognition through physiological signals. • Try out different classifiers and identify the optimal model for emotion recognition. • Attempting to improve the emotion detection reliability for both subject-dependent and subject-independent classification. • Conducting a comparison between the deep learning model and the multimodal machine learning model. This study explores a novel approach to emotion recognition through machine learning, addressing the limitations of previous methods. While deep learning has shown promise in this field, it often requires significant computational resources and time. In response, we propose a multimodal approach utilizing Feature-level Fusion (FLF) and Decision-level Fusion (DLF) to enhance performance while reducing complexity. The study focuses on integrating electroencephalogram (EEG), electromyography (EMG), and electrooculogram (EOG) signals. Signal preprocessing involves extracting statistical features, power spectral density (PSD), and incremental entropy analysis. Recursive Feature Elimination (RFE) is employed as a feature selector, facilitating the fusion of different signal features. Three fusion strategies are explored: EEG with EOG, EEG with EMG, and a combination of EEG with EOG and EMG. For classification, the Bagging Classifier and K-Nearest Neighbors Algorithm are chosen. Results demonstrate promising accuracy rates, with 95.7% for arousal, 96.41% for valence in subject-dependent classification, 93.68% for arousal, and 93.23% for valence in subject-independent classification. This approach presents a viable alternative to deep learning methods, offering improved performance with reduced computational burden. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Optimal control of an elastically connected rectangular plate–membrane system
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Kucuk, Ismail and Sadek, Ibrahim
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- 2005
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6. Discrimination of retinal images containing bright lesions using sparse coded features and SVM.
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Sidibé, Désiré, Sadek, Ibrahim, and Mériaudeau, Fabrice
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MEDICAL imaging systems , *FEATURE extraction , *BLOOD vessels , *SUPPORT vector machines , *DIABETIC retinopathy , *DISEASE progression - Abstract
Diabetic Retinopathy (DR) is a chronic progressive disease of the retinal microvasculature which is among the major causes of vision loss in the world. The diagnosis of DR is based on the detection of retinal lesions such as microaneurysms, exudates and drusen in retinal images acquired by a fundus camera. However, bright lesions such as exudates and drusen share similar appearances while being signs of different diseases. Therefore, discriminating between different types of lesions is of interest for improving screening performances. In this paper, we propose to use sparse coding techniques for retinal images classification. In particular, we are interested in discriminating between retinal images containing either exudates or drusen, and normal images free of lesions. Extensive experiments show that dictionary learning techniques can capture strong structures of retinal images and produce discriminant descriptors for classification. In particular, using a linear SVM with the obtained sparse coded features, the proposed method achieves superior performance as compared with the popular Bag-of-Visual-Word approach for image classification. Experiments with a dataset of 828 retinal images collected from various sources show that the proposed approach provides excellent discrimination results for normal, drusen and exudates images. It achieves a sensitivity and a specificity of 96.50% and 97.70% for the normal class; 99.10% and 100% for the drusen class; and 97.40% and 98.20% for the exudates class with a medium size dictionary of 100 atoms. [ABSTRACT FROM AUTHOR]
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- 2015
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7. Active control of a smart beam with time delay by Legendre wavelets
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Kucuk, Ismail, Sadek, Ibrahim, and Yilmaz, Yalcin
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ACTIVE noise & vibration control , *WAVELETS (Mathematics) , *ACTUATORS , *PIEZOELECTRIC device industry , *APPROXIMATION theory , *NUMERICAL analysis - Abstract
Abstract: Active vibration control in a flexible beam is investigated by taking into account the time-delay which may occur in voltage controlled piezoelectric actuators. The voltage applied to a piezoelectric patch actuator to suppress the dynamic responses of the beam at a specified terminal time is computed by solving an optimal control problem. The quadratic performance index function consists of related potential energy and kinetic energy at the terminal time as well as control effort as a penalty term. The solution method is based on a combination of spatial modal expansion and direct approximation approaches. The spatial modal expansion approach is used to transfer the optimal control problem of distributed parameter system (DPS) into the optimal control problem of a linear time-invariant lumped parameter system (LPS). A direct state-control parametrization approach is formulated where Legendre wavelets are employed to solve time delayed LPS. The operational matrices of integration and delay are utilized to reduce the solution of linear time-varying delayed systems to the solution of algebraic equations. Illustrative examples are included to demonstrate the applicability and the efficiency of the proposed method and the numerical results indicate the effectiveness of the proposed control mechanism. [Copyright &y& Elsevier]
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- 2012
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8. Optimal vibration control of piezolaminated smart beams by the maximum principle
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Kucuk, Ismail, Sadek, Ibrahim S., Zeini, Eiman, and Adali, Sarp
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MATHEMATICAL optimization , *VIBRATION (Mechanics) , *ACTUATORS , *PIEZOELECTRIC devices , *BERNOULLI-Euler method , *EIGENFUNCTION expansions , *CONTROL theory (Engineering) - Abstract
Abstract: Active control of a vibrating beam using piezoelectric patch actuators is considered. The specific structure to be studied is an Euler–Bernoulli beam with piezoelectric actuators bonded to the top and bottom surfaces of the beam. The equation of motion includes Heaviside functions and their derivatives due to finite size piezo patches which provide the control force to damp out vibrations. Optimal control theory is formulated with the objective function specified as a weighted quadratic functional of the dynamic responses of the beam which is to be minimized at a specified terminal time. The expenditure of the control forces is included in the objective function as a penalty term. The optimal control law is derived using a maximum principle developed by Sadek et al. . The maximum principle involves a Hamiltonian expressed in terms of an adjoint variable with the state and adjoint variables linked by terminal conditions leading to a boundary-initial-terminal value problem. The explicit solution of the problem is developed using eigenfunction expansions of the state and adjoint variables. The numerical results are given to assess the effectiveness and the capabilities of piezo actuation to damp out the vibrations. [Copyright &y& Elsevier]
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- 2011
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9. Coupled Galerkin and parameterization methods for optimal control of discretely connected parallel beams
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Sadek, Ibrahim, Abukhaled, Marwan, and Abualrub, Taher
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GALERKIN methods , *CONTROL theory (Engineering) , *WAVELETS (Mathematics) , *LEGENDRE'S functions , *MATHEMATICAL optimization , *NUMERICAL analysis , *LINEAR differential equations - Abstract
Abstract: Galerkin and wavelet methods for optimal boundary control of a couple of discretely connected parallel beams are proposed. First, the problem with boundary controls is converted into a problem with distributed controls. The problem is, then, reduced by a Galerkin-based approach into determining the optimal control of a linear time-invariant lumped parameter system, which will be solved by a wavelet-based method using Legendre wavelets. The integration-operational matrix and Kronecker product are utilized to significantly simplify the optimization problem into a system of linear equations. A numerical example is presented to demonstrate the applicability and the efficiency of the proposed method. [Copyright &y& Elsevier]
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- 2010
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10. Optimal boundary control of dynamics responses of piezo actuating micro-beams
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Sadek, Ibrahim, Kucuk, Ismail, Zeini, Eiman, and Adali, Sarp
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MATHEMATICAL optimization , *BEAM dynamics , *ACTUATORS , *TITANATES , *LEAD , *ZIRCON , *BANDWIDTHS - Abstract
Abstract: Optimal control theory is formulated and applied to damp out the vibrations of micro-beams where the control action is implemented using piezoceramic actuators. The use of piezoceramic actuators such as PZT in vibration control is preferable because of their large bandwidth, their mechanical simplicity and their mechanical power to produce controlling forces. The objective function is specified as a weighted quadratic functional of the dynamic responses of the micro-beam which is to be minimized at a specified terminal time using continuous piezoelectric actuators. The expenditure of the control forces is included in the objective function as a penalty term. The optimal control law for the micro-beam is derived using a maximum principle developed by Sloss et al. [J.M. Sloss, J.C. Bruch Jr., I.S. Sadek, S. Adali, Maximum principle for optimal boundary control of vibrating structures with applications to beams, Dynamics and Control: An International Journal 8 (1998) 355–375; J.M. Sloss, I.S. Sadek, J.C. Bruch Jr., S. Adali, Optimal control of structural dynamic systems in one space dimension using a maximum principle, Journal of Vibration and Control 11 (2005) 245–261] for one-dimensional structures where the control functions appear in the boundary conditions in the form of moments. The derived maximum principle involves a Hamiltonian expressed in terms of an adjoint variable as well as admissible control functions. The state and adjoint variables are linked by terminal conditions leading to a boundary-initial-terminal value problem. The explicit solution of the problem is developed for the micro-beam using eigenfunction expansions of the state and adjoint variables. The numerical results are given to assess the effectiveness and the capabilities of piezo actuation by means of moments to damp out the vibration of the micro-beam with a minimum level of voltage applied on the piezo actuators. [Copyright &y& Elsevier]
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- 2009
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11. A numerical approach to an optimal boundary control of the viscous Burgers’ equation
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Kucuk, Ismail and Sadek, Ibrahim
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BURGERS' equation , *NUMERICAL solutions to boundary value problems , *MATHEMATICAL optimization , *CONTROL theory (Engineering) , *VISCOSITY , *FOURIER series , *MATHEMATICAL programming , *COMPUTER simulation , *RUNGE-Kutta formulas - Abstract
Abstract: The dynamics of the forced Burgers’ equation subject to Dirichlet boundary conditions using boundary control is analyzed with the objective of minimizing the distance between the final state function and target profile along with the energy of the control. An efficient method is suggested to solve the optimal boundary control of the Burgers’ equation. The solution method involves the transformation of the original problem into one with homogeneous boundary conditions. This modifies the problem from one in which there are boundary controls to one in which there are distributed controls. The Modal space technique is applied on the distributed controls of the forced Burgers’ equation to generate a low-dimensional dynamical systems. The time-variant controls are approximated by a finite term of the Fourier series whose coefficients and frequencies giving optimal solutions are to be determined, thereby converting the optimal control problem into mathematical programming problem. The approximate solution space based on the control parameterization is obtained by using the Runge–Kutta method. Numerical simulations for the boundary controls are presented for various target functions to assess the efficiency of the proposed method. [Copyright &y& Elsevier]
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- 2009
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12. A comparison of three heart rate detection algorithms over ballistocardiogram signals.
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Sadek, Ibrahim and Abdulrazak, Bessam
- Subjects
HEART beat ,DISCRETE wavelet transforms ,SLEEP positions ,FIBER Bragg gratings ,WAVELET transforms ,OPTICAL fiber detectors ,SITTING position ,PHOTOPLETHYSMOGRAPHY - Abstract
Heart rate (HR) detection from ballistocardiogram (BCG) signals is challenging because the signal morphology can vary between and within-subjects. Also, it differs from one sensor to another. Hence, it is essential to evaluate HR detection algorithms across several datasets and under different experimental setups. In this paper, we studied the potential of three HR detection algorithms across four independent BCG datasets. The three algorithms were as follows: the multiresolution analysis of the maximal overlap discrete wavelet transform (MODWT-MRA), continuous wavelet transform (CWT), and template matching (TM). The four datasets were obtained using a microbend fiber optic sensor, a fiber Bragg grating sensor, electromechanical films, and load cells, respectively. The datasets were gathered from: a) 10 patients during a polysomnography study, b) 50 subjects in a sitting position, c) 10 subjects in a sleeping position, and d) 40 subjects in a sleeping position. Overall, CWT with derivative of Gaussian provided superior results compared with the MODWT-MRA, CWT (frequency B-spline), and CWT (Shannon). That said, a BCG template was constructed from DataSet1. Then, it was used for HR detection in the other datasets. The TM method achieved satisfactory results for DataSet2 and DataSet3, but it did not detect the HR of two subjects in DataSet4. The proposed methods were implemented on a Raspberry Pi. As a result, the average time required to analyze a 30-second BCG signal was less than one second for all methods. Yet, the MODWT-MRA had the highest performance with an average time of 0.04 s. [ABSTRACT FROM AUTHOR]
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- 2021
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13. A computational method for solving optimal control of a system of parallel beams using Legendre wavelets
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Sadek, Ibrahim, Abualrub, Taher, and Abukhaled, Marwan
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PROBLEM solving , *WAVELETS (Mathematics) , *HARMONIC analysis (Mathematics) , *BOUNDARY value problems - Abstract
Abstract: The optimal control of transverse vibration of two Euler–Bernoulli beams coupled in parallel by discrete springs is considered. An index of performance is formulated which consists of a modified energy functional of two coupled structures at a specified time and penalty functions involving the point control forces. The minimization of the performance index over these forces is subject to the equation of motion governing the structural vibrations, the imposed initial condition as well as the boundary conditions. By use of the modal space technique, the optimal control of distributed parameter systems is simplified into the optimal control of a linear time-invariant lumped-parameter systems. A computationally attractive method based on Legendre wavelets in time domain for solving the optimal control of the lumped parameter systems for any finite interval is proposed. Legendre wavelet integral operational matrix and the properties of a Kronecker product are used to find the approximated optimal trajectory and optimal law of the linear systems with respect to a quadratic cost function by only solving a linear system of algebraic equations. This method provides a straightforward and convenient approach for digital computation. A numerical example is provided to demonstrate the applicability and effectiveness of the proposed method. [Copyright &y& Elsevier]
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- 2007
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14. An efficient computational method for the optimal control problem for the Burgers equation
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Kucuk, Ismail and Sadek, Ibrahim
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NAVIER-Stokes equations , *TURBULENCE , *BOUNDARY value problems , *SYSTEMS engineering - Abstract
Abstract: Pointwise control of the viscous Burgers equation in one spatial dimension is studied with the objective of minimizing the distance between the final state function and target profile along with the energy of the control. An efficient computational method is proposed for solving such problems, which is based on special orthonormal functions that satisfy the associated boundary conditions. Employing these orthonormal functions as a basis of a modal expansion method, the solution space is limited to the smallest lower subspace that is sufficient to describe the original problem. Consequently, the Burgers equation is reduced to a set of a minimal number of ordinary nonlinear differential equations. Thus, by the modal expansion method, the optimal control of a distributed parameter system described by the Burgers equation is converted to the optimal control of lumped parameter dynamical systems in finite dimension. The time-variant control is approximated by a finite term of the Fourier series whose unknown coefficients and frequencies giving an optimal solution are sought, thereby converting the optimal control problem into a mathematical programming problem. The solution space obtained is based on control parameterization by using the Runge–Kutta method. The efficiency of the proposed method is examined using a numerical example for various target functions. [Copyright &y& Elsevier]
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- 2006
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15. Deflection control of elastically restrained laminated frames under deterministic and uncertain loads using induced strain actuators
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Adali, Sarp, Sadek, Ibrahim S., Bruch, John C., Sloss, James M., and Cagdas, Izzet U.
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AUTOMATIC control systems , *ACTUATORS , *STRAINS & stresses (Mechanics) , *BENDING moment - Abstract
Abstract: Optimal induced strain actuator sizes for an L-shaped laminated frame are determined under deterministic and uncertain loads with the objective of minimizing the tip deflection. The bending moments generated by the induced strain actuators control the deflection in order to minimize the maximum deflection. The frame is elastically restrained at the tip point and is subjected to a tip load which is specified for the deterministic case and lies in an uncertainty domain in the uncertain case. The specific uncertain loading studied in the present paper involves a load of given magnitude but of unknown direction which should be determined to induce the highest tip deflection caused by the least favorable loading. The effects of the elastic restraints and actuator locations on the deflection behaviour are investigated. It is shown that the optimal actuator size depends on the magnitude of the moments provided by the actuators. Moreover, it is observed that a deterministic design under an uncertain load leads to excessive deflections indicating the necessity of a robust design. [Copyright &y& Elsevier]
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- 2006
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16. Optimization of composite plates with piezoelectric stiffener-actuators under in-plane compressive loads
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Adali, Sarp, Sadek, Ibrahim S., Bruch, John C., and Sloss, James M.
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MATHEMATICAL optimization , *EXPERIMENTAL design , *ELECTRIC fields , *ELECTROMAGNETIC fields - Abstract
Abstract: Stiffeners which are used to strengthen a plate can be constructed of piezoceramic materials and subsequently used as piezo actuators to improve the load carrying capacity of the plate. In the present study, a fibre composite plate with initial imperfections and under in-plane compressive loads is studied with a view towards minimizing its deflection using the piezo actuators and the fibre orientations. Piezoceramic stiffeners are bonded symmetrically on the top and bottom of the plate and deployed as actuators. Two cases of electric fields, namely, the in-phase and out-of-phase voltages are applied to the actuators. The presence of initial deflections leads to deformation under the in-plane compressive loads which should be less than the critical buckling load. Two cases of initial imperfections are considered, and the first one is the deterministic initial deflections which are known a priori and as such they are given as input parameters for the problem. In the second case the initial deflections are uncertain and they have to be obtained according to a given criterion. In the present study they are determined to produce the least favourable initial deflection (largest deflection) at a given point and the solution is obtained by convex modelling. The effect of the actuators, the ply angles and the voltage are studied and their effects on the transverse deflection are investigated. A performance index involving the L 2 norm of the deflections is minimized using the piezo effect and as well as the ply angles the optimal values of which are determined for various problem parameters. [Copyright &y& Elsevier]
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- 2005
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17. Legendre wavelet operational matrix of derivative for optimal control in a convective–diffusive fluid problem.
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Abualrub, Taher and Sadek, Ibrahim
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LEGENDRE'S functions , *WAVELETS (Mathematics) , *OPERATIONS research , *OPTIMAL control theory , *CONVECTIVE flow , *PROBLEM solving - Abstract
Abstract: We consider the problem of controlling the model of one-dimensional fluid flow through a soil packed tube in which a contaminant is initially distributed. A fluid is pumped through a tube to remove the contaminant. The control problem is to determine the optimal convective velocity due to the fluid being pumped by minimizing a given performance criterion. The performance criterion is chosen to be a combination of the total contaminant at the final time and the cost of the control. The set of orthogonal Fourier trigonometry series is used as a basis function of the Galerkin procedure to lump the distributed parameter system. A Legendre wavelet operational matrix of derivative is used to approximate the control and modal state variables. The main characteristics of this technique is that it reduces these problems to those of solving a system of algebraic equations, thus greatly simplifying the problem. The effectiveness of the proposed approach is illustrated numerically and the results are quite satisfactory. [Copyright &y& Elsevier]
- Published
- 2014
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18. Optimal control of a distributed parameter system with applications to beam vibrations using piezoelectric actuators.
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Kucuk, Ismail, Sadek, Ibrahim, and Yilmaz, Yalcin
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DISTRIBUTED parameter systems , *OPTIMAL control theory , *PIEZOELECTRIC actuators , *PROBLEM solving , *GALERKIN methods , *VARIATIONAL approach (Mathematics) - Abstract
Abstract: This paper addresses the issue of the active vibration control of the transverse modes in a flexible elastic systems. The control is implemented by discrete sets of piezoelectric actuators that apply the optimal forces. The performance index is a time-dependent quadratic functional of state variables and their time derivatives, and control forces which are determined by minimizing the objective functional subject to a penalty term on the control functions. A combination of Galerkin and variational approaches are employed to determine the control forces in the time domain explicitly in terms of coupled amplitudes and velocities. The effectiveness of the proposed method is demonstrated by applying it to a physical problem controlled by piezoelectric patch actuators. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
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19. Active vibration control of an elastically connected double-string continuous system
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Kucuk, Ismail and Sadek, Ibrahim
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FUNCTIONAL analysis , *FUNCTIONAL equations , *INTEGRAL equations , *AUTOMATIC control systems - Abstract
Abstract: The paper deals with the optimal control of a distributed host structure consisting of two elastically connected complex continuous double-string system and subjected to certain excitation load. Investigation of the behavior of such system is of great theoretical and practical importance. A technique is proposed to actively damp out the undesired vibrations in the structures by a combination of applied actuators and displacement feedback gains. Two performance measures, involving energies at the terminal time as well as applied and feedback control efforts, are introduced. The optimality conditions of the applied actuators are derived by using the method of eigenfunction expansion and calculus of variations. The feedback parameters are numerically determined from the solution of a minimization problem. The proposed approach is illustrated by a numerical example involving a system which consists of two strings subjected to a continuous load. [Copyright &y& Elsevier]
- Published
- 2007
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20. Optimal sizing of piezo-actuators for minimum-deflection design of frames under uncertain loads
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Adali, Sarp, Sadek, Ibrahim S., Bruch, John C., Sloss, James M., and Cagdas, Izzet U.
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AUTOMATIC control systems , *AUTOMATIC gain control , *AUTOMATIC timers , *AUTOMATION - Abstract
Abstract: Optimal piezo-actuator sizes and locations for a frame structure under bending load uncertainty are determined with the objective of minimizing the deflection under worst case of loading. The bending moments generated by the piezo-actuators are used for deflection control, i.e., to minimize the maximum deflection. The frame is subjected to a tip load which lies in an uncertainty domain with regard to its magnitude and direction. The specific uncertain loading studied in the present paper involves a load of given magnitude but of unknown direction, which should be determined to produce the highest deflection. The worst case of loading depends on the size and location of the actuators leading to a nested problem of optimization (design) and anti-optimization (uncertainty problem). Results are given for deterministic and uncertain loading conditions. [Copyright &y& Elsevier]
- Published
- 2007
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21. Modeling, Simulation and Applied Optimization
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Sadek, Ibrahim, Kucuk, Ismail, El-Tarhuni, Mohamed, Anabtawi, Mahmoud, and Abdalla, Jamal A.
- Published
- 2006
- Full Text
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22. Modeling, simulation and applied optimization
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El-Keib, Abdurrahim and Sadek, Ibrahim
- Published
- 2008
- Full Text
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23. Modeling, simulation, and applied optimization
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El-Tarhuni, Mohamed, Abdalla, Jamal A., Sadek, Ibrahim, Kucuk, Ismail, Anabtawi, Mahmoud, and Al-Jarrah, Mohammad
- Published
- 2011
- Full Text
- View/download PDF
24. Integral equation approach for piezo patch vibration control of beams with various types of damping
- Author
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Kayacık, Özcan, Bruch, John C., Sloss, James M., Adali, Sarp, and Sadek, Ibrahim S.
- Subjects
- *
AUTOMATIC control systems , *ENGINEERING instruments , *DIFFERENTIAL equations , *LINEAR systems , *INTEGRAL equations - Abstract
Abstract: The Euler–Bernoulli model of transverse vibrations of a cantilever beam is extended to include viscous and Kelvin–Voigt (strain rate) damping to study active vibration control under damping. The controls are of feedback type with displacement and velocity feedback controls provided by full length or patch piezoelectric actuators and sensors bonded to the top and the bottom of the beam. The resulting partial differential equation which contains discontinuities in a differential equation setting due to patch actuators is solved by formulating the problem in an integral equation setting which eliminates the singularities. The solution is reduced to the solution of a linear system of equations by using an orthonormal set of the eigenfunctions of the freely vibrating beam which provide an accurate approximation to the controlled vibration case. Control effectiveness is investigated in terms of changes in the damped natural frequencies for different gains, damping coefficients, and patch locations. The effect of the displacement and velocity feedback controls and problem parameters on the real and complex parts of the fundamental, second and third order frequencies is discussed with a view towards establishing the damped and oscillatory behaviour of the piezo controlled beams. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
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