This thesis presents a means for representing and computing beliefs in the form of arbitrary probability density functions with a guarantee for the ongoing validity of such beliefs over indefinte time frames. The foremost aspect of this proposal is the introduction of a general, theoretical, solution to the guaranteed state estimation problem from within the recursive Bayesian estimation framework. The solution presented here determines the minimum space required, at each stage of the estimation process, to represent the belief with limited, or no, loss of information. Beyond this purely theoretical aspect, a number of numerical techniques, capable of determining the required space and performing the appropriate spatial reconfiguration, whilst also computing and representing the belief functions, are developed. This includes a new, hybrid particle-element approach to recursive Bayesian estimation. The advantage of spatial reconfiguration as presented here is that it ensures that the belief functions consider all plausible states of the target system, without altering the recursive Bayesian estimation equations used to form those beliefs. Furthermore, spatial reconfiguration as proposed in this dissertation enhances the estimation process since it allows computational resources to be concentrated on only those states considered plausible. Autonomous maritime search and rescue is used as a focus application throughout this dissertation since the searching-and-tracking requirements of the problem involve uncertainty, the use of arbitrary belief functions and dynamic target systems. Nevertheless, the theoretical development in this dissertation has been kept general and independent of an application, and as such the theory and techniques presented here may be applied to any problem involving dynamic Bayesian beliefs. A number of numerical experiments and simulations show the efficacy of the proposed spatially reconfigurable representations, not only in ensuring the validity of the belief functions over indefinite time frames, but also in reducing computation time and improving the accuracy of function approximation. Improvements of an order of magnitude were achieved when compared with traditional, spatially static representations.

This thesis presents a means for representing and computing beliefs in the form of arbitrary probability density functions with a guarantee for the ongoing validity of such beliefs over indefinte time frames. The foremost aspect of this proposal is the introduction of a general, theoretical, solution to the guaranteed state estimation problem from within the recursive Bayesian estimation framework. The solution presented here determines the minimum space required, at each stage of the estimation process, to represent the belief with limited, or no, loss of information. Beyond this purely theoretical aspect, a number of numerical techniques, capable of determining the required space and performing the appropriate spatial reconfiguration, whilst also computing and representing the belief functions, are developed. This includes a new, hybrid particle-element approach to recursive Bayesian estimation. The advantage of spatial reconfiguration as presented here is that it ensures that the belief functions consider all plausible states of the target system, without altering the recursive Bayesian estimation equations used to form those beliefs. Furthermore, spatial reconfiguration as proposed in this dissertation enhances the estimation process since it allows computational resources to be concentrated on only those states considered plausible. Autonomous maritime search and rescue is used as a focus application throughout this dissertation since the searching-and-tracking requirements of the problem involve uncertainty, the use of arbitrary belief functions and dynamic target systems. Nevertheless, the theoretical development in this dissertation has been kept general and independent of an application, and as such the theory and techniques presented here may be applied to any problem involving dynamic Bayesian beliefs. A number of numerical experiments and simulations show the efficacy of the proposed spatially reconfigurable representations, not only in ensuring the validity of the belief functions over indefinite time frames, but also in reducing computation time and improving the accuracy of function approximation. Improvements of an order of magnitude were achieved when compared with traditional, spatially static representations.

When simulating complex flows, there are some physical situations that exhibit large fluctuations in particle density such as: planetary reentry, ablation due to arcing, rocket exhaust plumes, etc. When simulating these events, a high level of physical accuracy can be achieved with kinetic methods otherwise known as particle methods. However, this high level of physical accuracy requires large amounts of computation time. If the simulated flow is in collisional equilibrium, then less computationally intensive continuum methods, otherwise known as fluid methods, can be utilized. Hybrid Particle-Continuum (HPC) codes attempt to blend particle and fluid solutions in order to reduce computation time for transitional flows that exhibit both continuum and rarefied flow in a single domain. This thesis details the development of an HPC code in OpenFoam for Cal Poly's Aerospace Engineering department. The primary benchmark for the solver, named hybridFoam, was to simulate a 1D sod-shock simulation. This primary goal was achieved and a collection of test simulations were conducted to map out the solvers current capabilities and identify where future development efforts should focus.

Cette thèse s’intéresse principalement à la réalisation de nouvelles encres électrophorétiques pour les applications de type papier électronique couleur. Une méthode simple et peu contraignante basée sur la polymérisation en dispersion a été développée, permettant de réaliser de manière contrôlée et en milieu peu polaire des particules de polymère chargeables positivement ou négativement. Puis, grâce à ce nouvel outil, des particules électrophorétiques hybrides ont été synthétisées à partir de pigments inorganiques et caractérisées sous champ électrique. Enfin une nouvelle solution pour aller vers des dispositifs couleur a été proposée et la fabrication d’un démonstrateur test a été abordée. / The effective sharing of information is a key parameter in our actual society. Electronic paper based on the controlled motion of electrophoretic particles appears thus promising since it combines the advantages of the usual paper (flexibility, reflective display) and the capacity to refresh information on the same support like the more common LCD or OLED technologies. Electrophoretic inks are composed of coloured charged particles which migrate under an electrical field between two electrodes. Depending of the position of the particles on the front plane, the colour on the screen can be tuned. The design of electrophoretic particles based on pigment or dyed polymer and their integration in electronic devices were successfully achieved during the last decade but are still limited to a two colour-electrophoretic system. Up to date the majority of these particles were synthesized in aqueous media and the electrophoretic mobility was achieved by a ionic stabilizer or by a polyelectrolyte surfactant. Moreover the final electrophoretic particles incorporated in the electronic devices have to be dispersed in an organic media (paraffin oil) in order to achieve the desired stability of the display and thus leads to a large variety of problems during the phase exchange process.In this work our goals were to rationalize and improve the ink synthesis as well as to design electrophoretic inks with the full colour panel in order to realize the next generation of electrophoretic displays. We performed the particle synthesis by using an organic dispersion technique in aliphatic hydrocarbon solvents leading to chargeable electrophoretic particles with a good size control over a large range (from 75nm to 20µm) and a good stability. In order to obtain the full color panel, the encapsulation of several inorganic pigments was achieved by using the same technique and the electrophoretic behaviour of the resulting inks was characterized in a cell specially designed for electrophoretic measurements in organic media.

Au cours de ces travaux de thèse, la synthèse et le comportement électrophorétiquede particules hybrides dispersées en présence d'un nouveau contrôleur de charge, latridodécylamine, en milieu électrophorétique (non-polaire), ont été étudiés pour des applicationsde type papier électronique. Dans le but de contrôler et comprendre les interactions présentesdans ce système, la tridodécylamine a tout d'abord été examinée seule dans le milieu souhaité.Il a été observé que ce tensioactif, solubilisé dans un milieu type huile paraffine, a uneconcentration micellaire critique approximative de 250 mM et apporte des charges dans lemilieu. Ensuite, la synthèse par polymérisation en dispersion ou par voie sol gel a permisd'obtenir des particules inorganiques, polymères ou hybrides type framboise, stables en milieunon-polaire. Leur comportement électrophorétique en présence du nouveau contrôleur decharge a été élucidé. En outre, il a été montré que des interactions acido-basiques avec lesgroupements hydroxyles des pigments inorganiques et le tensioactif donnent des particuleshybrides chargées négativement. Celles-ci ont par la suite été intégrées dans une encreélectrophorétique et testées dans un dispositif prototype innovant, le contrôle del'électrophorèse étant géré via un polymère ferroélectrique. / In this work, the synthesis and the electrophoretic behavior of hybrid particlesdispersed in apolar media, in the presence of a new charge control agent, the tridodecylamine,have been investigated for electronic paper applications. In order to control and to understandinteractions present in the system, the tridodecyamine was studied in the apolar medium. It hasbeen observed that this surfactant, solubilized in a non-polar medium, has a critical micelleconcentration of approximately 250mM and creates charges in the medium. Then, the synthesisby polymerisation in dispersion or by using a sol-gel process gave rise to the creation ofinorganic, polymeric or raspberry type hybrid particles, stable in non-polar media. Theirelectrophoretic behavior in the presence of tridodecylamine was elucidated. Acid-baseinteractions between hydroxyl groups from inorganic material surfaces and surfactant led to thecreation of negatively charged hybrid particles. These particles were integrated into anelectrophoretic ink and tested into an innovative electrophoretic device where theelectrophoresis is monitored via a ferroelectric polymer.

The development of improved numerical methods for computer simulation of high velocity impact dynamics is of importance in a variety of science and engineering fields. The growth of computing capabilities has created a demand for improved parallel algorithms for high velocity impact modeling. In addition, there are selected impact applications where experimentation is very costly, or even impossible (e.g. when certain bioimpact or space debris problems are of interest). This dissertation extends significantly the class of problems where particle-element based impact simulation techniques may be effectively applied in engineering design. This dissertation develops a hybrid particle-finite element method for a general hexahedral mesh. This work included the formulation of a numerical algorithm for the generation of an ellipsoidal particle set for an unstructured hex mesh, and a new interpolation kernel for the density. The discrete model is constructed using thermomechanical Lagrange equations. The formulation is validated via simulation of published impact experiments. / text

The ionospheric environment has become a focal point in the study of earthquake-related anomalies. In particular, both electromagnetic anomalies and particle bursts have been detected in the ionosphere and proposed as potential seismo-related phenomena. This thesis addresses the challenges in distinguishing earthquake-induced electromagnetic anomalies from the complex and variable background of ionospheric signals. Utilizing data from the CSES-01 satellite, this work introduces a robust methodology for characterizing both medium-long and short-duration electromagnetic signals in the ionosphere. A new approach to defining ionospheric EM background is proposed, considering temporal and geographical variations, and a statistically rigorous definition of anomalies is introduced. Additionally, a novel algorithm is developed for the efficient detection of short-duration whistler waves, revealing significant insights into their spatiotemporal distributions. To explore the coupling mechanisms between electromagnetic anomalies and particle bursts, numerical simulations using a hybrid particle-in-cell code were conducted, simulating ionospheric plasma interactions with small amplitude Alfvén waves. The results demonstrate modifications in ion velocity distributions and the emergence of fast ion beams, providing the first estimates of time delays between the impact of the electromagnetic waves and plasma disturbances. This research advances the understanding of seismo-ionospheric coupling, offering valuable tools for the identification of earthquake-related anomalies.

This research presents a Hybrid Particle Swarm Optimization with Bat Algorithm (HPSOBA) based approach to solve Optimal Reactive Power Dispatch (ORPD) problem. The primary objective of this project is minimization of the active power transmission losses by optimally setting the control variables within their limits and at the same time making sure that the equality and inequality constraints are not violated. Particle Swarm Optimization (PSO) and Bat Algorithm (BA) algorithms which are nature-inspired algorithms have become potential options to solving very difficult optimization problems like ORPD. Although PSO requires high computational time, it converges quickly; while BA requires less computational time and has the ability of switching automatically from exploration to exploitation when the optimality is imminent. This research integrated the respective advantages of PSO and BA algorithms to form a hybrid tool denoted as HPSOBA algorithm. HPSOBA combines the fast convergence ability of PSO with the less computation time ability of BA algorithm to get a better optimal solution by incorporating the BA’s frequency into the PSO velocity equation in order to control the pace. The HPSOBA, PSO and BA algorithms were implemented using MATLAB programming language and tested on three (3) benchmark test functions (Griewank, Rastrigin and Schwefel) and on IEEE 30- and 118-bus test systems to solve for ORPD without DG unit. A modified IEEE 30-bus test system was further used to validate the proposed hybrid algorithm to solve for optimal placement of DG unit for active power transmission line loss minimization. By comparison, HPSOBA algorithm results proved to be superior to those of the PSO and BA methods. In order to check if there will be a further improvement on the performance of the HPSOBA, the HPSOBA was further modified by embedding three new modifications to form a modified Hybrid approach denoted as MHPSOBA. This MHPSOBA was validated using IEEE 30-bus test system to solve ORPD problem and the results show that the HPSOBA algorithm outperforms the modified version (MHPSOBA). / Electrical and Mining Engineering / M. Tech. (Electrical Engineering)