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 26 for “"Density evolution"”.
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Modeling dislocation density evolution in continuum crystal plasticity
… of geometrically necessary dislocation (GND) density in continuum formulations through plastic strain gradients, a single crystal plasticity model based on dislocation density state variables is developed. The density state variables evolve from initial conditions according to equations based …
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A density evolution analysis of turbo product codes
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.
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Diffusion-driven flows due to an obstruction layer
… that impermeable obstructions have on the density evolution of a stratified fluid is developed theoretically and demonstrated experimentally. With the use of two different types of obstruction layers, the theory is shown to accurately predict the density evolution.
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On the construction of some capacity-approaching coding schemes
… bound. The second scheme is based on low-density parity-check (LDPC) codes. We first demonstrate that we can translate threshold values of an LDPC code between channels accurately using a simple mapping. We develop some models for density evolution from this observation, namely …
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On performance analysis and implementation issues of iterative decoding for graph based codes
… mechanism. Among these long codes are low-density parity-check (LDPC) code and product code, which render brilliant performance. In this work, iterative decoding algorithms for LDPC code and product code are studied in the context of belief propagation. A large part of this work concerns …
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Development and preliminary numerical investigations of a dislocation density-based finite-strain rate-dependent elastoplasticity constitutive model
… numerical investigations of a dislocation density-based finite-strain rate-dependent elastoplasticity constitutive model Finite-strain elastoplasticity constitutive models suitable for process-scale simulation are typically developed from empirical observations of phenomena of interest. …
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Modeling Collective Behavior of Dislocations in Crystalline Materials
… work deals with the kinematics of dislocation density evolution. An explicit Galerkin/least-squares formulation is introduced for the quasilinear evolution equation, which leads to a symmetric and well-conditioned system of equations with constant coefficients, making it attractive for …
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The quark-hadron transition and hot hadronic matter in the early universe
Various calculations· of the evolution of the hadron gas in the early universe are carried out. To determine the starting point for the evolution equations a phase transition between the quark-gluon plasma phase and the hadron gas phase is constructed. A simple calculation leads to an estimate of …
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Modelling of dislocation-mobility-controlled brittle-to-ductile transition
… deformation with constant dislocation density and a plastic strain rate proportional to the dislocation velocity. The constitutive model derivation is given along with the numerical results for several loading rates. The constant-dislocation-density material is capable of predicting the …
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Mesoscopic lattice Boltzmann nemato-dynamics.
… two coupled LBE schemes, the standard momentum density distribution and a new link angle distribution. To achieve evolution, the link angle distribution undergoes a Bhatnagar-Gross-Krook (BGK) collision step and advects (propagates) in unit time with the momentum densities. Anisotropy is …
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Investigation of mechanical behavior of Alloy 709 for advanced fast reactor applications
… fraction, active dislocation types and their density evolution, all as a function of temperature, was revealed. These techniques functioned to form a complete picture of the development of the Alloy 709 microstructure during deformation and the subsequent changes in deformation behavior due to …
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Design and modelling of ultra-high strength steels: nanoprecipitation and plasticity
… precipitation, grain size and dislocation density evolution. It was observed that the addition of silicon reduces the rate of martensite recovery, owing to the reduced cross-slip in the ferrite lattice. A plasticity model based on irreversible thermodynamics and EBSD characterisation was …
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Importance sampling for LDPC codes and turbo-coded CDMA
Low-density parity-check (LDPC) codes have shown capacity-approaching performance with soft iterative decoding algorithms. Simulating LDPC codes at very low error rates normally takes an unacceptably long time. We consider importance sampling (IS) schemes for the error rate estimation of LDPC …
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Polarization VLBI monitoring of BL lacertae - kinematics, faraday effects and intermediate scale structure
… in both total intensity and polarized flux density. A number of superluminal knots are identified in the jet with speeds Sc, comparable to those found in previous studies of this source. It has been noted in past observations that the electric vectors of knots in the jets of BL Lac objects …
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High Speed Turbo Tcm Ofdm For Uwb And Powerline System
… error protection. Results have been confirmed by density evolution. The effect of impulsive noise on TTCM coded OFDM system is also evaluated. A modified iterative bit MAP decoder is provided for channels with impulsive noise with different impulsivity.
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Unreliable and resource-constrained decoding
… on iterative message-passing decoders for low-density parity check (LDPC) codes is studied. Concentration of decoding performance around its average is shown to hold. Density evolution equations for noisy decoders are derived. Decoding thresholds degrade smoothly as decoder noise increases, and …
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Attacks on medical data and centralized social platforms: PU learning and graphical inference
Embargo set by: Seth Robbins for item 121048 Lift date: 2024-01-12T22:35:30Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system
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Dynamics of deep-submarine explosive eruptions
… magma with the ambient seawater and explore the density and spatial evolution of the subsequent flow that forms. In chapter 2, we consider the initial mixing and rise of an explosive eruption in a quiescent ambient environment via a series of numerical integral models and find that a submarine …
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On The Design Of Physical Layer Rateless Codes
… concatenating LT codes with high-rate outer low-density parity-check (LDPC) codes. Although these codes were originally developed for binary erasure channel (BEC), due to their rateless feature, they are being investigated and designed for their use in noisy channels. It is known that LT codes …
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Mass transfer and chemical interactions in subduction zones
… investigates the phase equilibria, melting, and density evolution of mélange rocks that formed by mixing and fluid-rock interactions. Results show that melting of mélanges is unlikely to occur along slab-tops at pressures ≤ 2.5 GPa. Accordingly, diapirism into the hotter mantle wedge would be …
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