Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 22 for “"discrete system"”.
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The Transient Response of Flat Plates Using the Finite Element Method
In the finite element method a discrete system is derived to approximate a continuum. A discretizing method is justified for this investigation by comparing the dynamic analysis of a discrete system with that of a plate continuum using the variational calculus. The transient response of the former …
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The role of smoothing effect in some dispersive equations
… dispersive equations. Second, we exploit a discrete version of the smoothing effect to study a discrete system of particles and how to approximate it by a continuous dispersive equation. Third, we use an anisotropic version of the smoothing effect to establish the local well-posedness theory …
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The spectral conforming model and its applications
… of the eigenvalues of the underlying continuous system corresponding to the low spectrum. The new discrete model, namely the spectral conforming model, is developed to predict the eigenvalues of continuous systems in both the low and high spectra. The spectral conforming models are developed …
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BIFURCATION AND CHAOS OF NONLINEAR VIBRO-IMPACT SYSTEMS
<p>Vibro-impact systems are extensively used in engineering and physics field, such as impact damper, particle accelerator, etc. These systems are most basic elements of many real world applications such as cars and aircrafts. Such vibro-impact systems possess both the continuous characteristics as …
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Continuous-time multivariable system identification
… identification of continuous-time multivariable systems. Direct methods of identification, i.e. identifying a continuous-time model directly from samples of input-output data, are considered briefly. Of primary consideration is the indirect method of identification, which can be considered as a …
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Methodologies for Broadband Electromagnetic Modeling of on-Chip Semiconductor Substrate Noise
… it maintains the transpose property between the discrete curl operators for electric and magnetic fields. This is a key ingredient for the implementation of a global discrete system that is energy conserving, consistent with the modeled continuous problem; hence any subgridding induced, late time …
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System Identification of a Cantilever Beam with Interferometer Measurement Using Adaptive Filters
… commonly used in high-precision motion control systems, is rarely adopted in experimental vibration analysis because its installation and mounting is invasive to dynamical systems. However, metrology systems that already utilize laser interferometry, such as profilometry in semiconductor …
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Cycle-to-cycle control of reconfigurable die sheet metal forming
… questions. The first is, "Can a multivariable discrete system control theory be used to model a sheet metal shape control process?" The second question is, "Does such a "cycle to cycle control system provide a significant improvement over the present industry standard control methods". To …
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Wave motion in finite and infinite media using the Thin-Layer Method
… of general solutions and frequency spectra for discrete homogeneous full-spaces, which are obtained in closed-form with the aid of a finite difference scheme. Then, we determine the optimal combination of the consistent and lumped mass matrices by introducing tuning factors into the discrete …
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Unified Multilevel Adaptive Finite Element Methods for Elliptic Problems
… constant of proportionality, (ii) solves the discrete system to the accuracy of the discretization error, (iii) is able to achieve the optimal order of convergence of the discretization error in the presence of singularities. Numerical experiments confirm this for linear, quadratic and cubic …
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Nonlinear waves in systems with PT/CP - symmetric potentials
… nonlinear lattice dynamical models is the discrete nonlinear Schrödinger (DNLS) equation [1]. Particularly, the discrete system and lattice solitons are the main objects of investigation in this work. In this thesis, we consider a chain of dimers, that is modelled by linearly coupled DNLS …
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Multi-electrode stimulation and measurement patterns versus prior information of fast 3D EIT
… boundary voltage measurements, the resulted discrete system is heavily underdetermined and ill-conditioned. Therefore, a sensible step to overcome this problem is to collect as many measurements as the number of the finite elements composing the medium. From one hand, this is not practically …
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Development of cochlear models with high computational efficiency by using spatial and parametric transformations
… and direct elimination for solving the discrete system of equations. Performance: The performance is evaluated using two developed simulative criteria for each of the four transformations. For the increased dissipation transformation, we investigate individual deviation measures as part …
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Discrete Modeling and Sliding Mode Control of Piezoelectric Actuators
… wide applications in various nano-positioning systems. However, existence of various effects in PEAs, such as hysteresis and creep, as well as dynamics can seriously degrade the PEA performance or even lead to instability. This raises a great need to model and control PEAs for improved …
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Contributions to the dynamics of helicopters with active rotor controls
… helicopter with a Higher Harmonic Control (HHC) system for vibration reduction. The analysis includes the rigid body dynamics of the helicopter and blade flexibility. The gain matrix is assumed to be fixed and computed off-line. The discrete elements of the HHC control loop are rigorously …
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Manual and Automated Measurement of the Chemical Oxygen Demand (COD) of Wastewaters
… A twofold requirement for an automated COD. system is outlined. Experiments with a commercial continuous flow system showed it to be unsuitable for the both requirements. Work with a hybrid part dioscrete, part continuous flow system is described. Some useful informations was gained but the …
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Spiky strings and the AdS/CFT correspondence
… “large” spikes may be used in order to extract a discrete system of degrees of freedom from string theory, which can then be matched with the degrees of freedom of the dual gauge theory operators, and how “small” spikes are in fact very similar to the Giant Magnons living in R × S2.
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Discrete Wave Propagation In Quadratically Nonlinear Media
Discrete models are used in describing various microscopic phenomena in many branches of science, ranging from biology through chemistry to physics. Arrays of evanescently coupled, equally spaced, identical waveguides are prime examples of optical structures in which discrete dynamics can be easily …
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Finite Element Modeling Driven by Health Care and Aerospace Applications
… finite element method can reduce a continuous system to a discrete idealization that can be solved in the same manner as a discrete system, provided the continuum is discretized into a finite number of simple geometric shapes (e.g., triangles in two dimensions or tetrahedrons in three …
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