Mobility modeling is a critical step in the ground vehicle acquisition process for military vehicles. Mobility modeling tools, and in particular the NATO Reference Mobility Model (NRMM), have played a critical role in understanding the mission-level capabilities of ground vehicles. This understanding via modeling supports not only developers during early vehicle design but also decision makers in the field previewing the capabilities of ground vehicles in real-world deployments. Due to decades of field testing and operations, mobility modeling for traditional ground vehicles is well-understood; however, mobility modeling tools for evaluating autonomous mobility are sparse. Therefore, this dissertation proposes and derives a Reference Autonomous Mobility Model (RAMM). The RAMM leverages cutting-edge modeling and simulation tools to build a mobility model that serves as the mission-level mobility modeling tool currently lacking in the unmanned ground vehicle (UGV) community, thereby filling the current analysis gap in the autonomous vehicle acquisition cycle. The RAMM is built on (1) a thorough review of theories of verification and validation of simulations, (2) a novel framework for validating simulations of autonomous systems and (3) the mobility modeling framework already established by the NRMM. These building blocks brought to light the need for new, validated modeling and simulation (M&S) tools capable of simulating, at a highidelity, autonomous unmanned ground vehicle operations. This dissertation maps the derivation of the RAMM, starting with a history of verification of simulation models and a literature review of current autonomous mobility modeling methods. In light of these literature reviews, a new framework for V&V of simulations of autonomous systems is proposed, and the requirements for and derivation of the RAMM is presented. This dissertation concludes with an example application of the RAMM for route planning for autonomous UGVs. Once fully developed, the RAMM will serve as an integral part in the design, development, testing and evaluation, and ultimate fielding of autonomous UGVs for military applications.

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Communicative acts constitute organizations as social entities. I build upon the most structured previous analysis of this process, the four flows framework, by introducing a complex systems model of how organization emerges along a continuum, thereby enabling measurement of the growth and decline of partial organizations. I validate my approach using simulated data from two stochastic agent-based models and 30 historical case studies of insurgency. I show that the four flows may be used to assess the historical victor of a conflict, or to track the emergence of an organization from real-time communication network data. My results demonstrate the complex interrelationship of the four flows, and how they relate to social phenomena such as information asymmetry, individual versus group interest, governance, and the development of community structure. I reaffirm the centrality of these flows to the phenomenon of organization, while challenging the minimum requirements for it to begin, by showing that organization spontaneously emerges in a population as a result of markers of affiliation and human cognitive biases. / Doctor of Philosophy / Humans organize collective behavior by communicating. Prior research has shown that all organizations establish the costs and benefits of membership, distinctions from other organizations, enduring protocols, and approaches to short-term coordination. The strength with which organizations define each of these traits emerges on a continuum from a nascent organization to a robust one. My work is the first to place these acts of communication in an engineering model, showing how an organization works as a system to reduce collective uncertainty. I first explore my model in a computer simulation, demonstrating that each of the four processes can be measured. I then quantify the strength of each process in 30 case studies of insurgency, measuring the changing effectiveness of the insurgents and their state opponents at establishing themselves as the governing entity in an area. My technique accurately predicts the outcome of all 30 case studies. Finally, using a second simulation, I demonstrate measures of all four processes in communication records and show that organization may be the result of merely recognizing oneself as part of a group, amid basic patterns in human thinking, rather than evidence of cooperation toward shared objectives.

This dissertation investigates the evacuees' behavior under hurricane evacuation conditions and develops an agent-based travel demand model system for hurricane evacuation simulation using these behavioral findings. The dissertation econometrically models several important evacuation decisions including evacuate-stay, accommodation type choice, evacuation destination choice, evacuation mode choice, departure time choice, and vehicle usage choice. In addition, it explicitly considers the pre-evacuation preparation activities using activity-based approach. The models are then integrated into a two-module agent-based travel demand model system. The dissertation first develops the evacuate-stay choice model using the random-coefficient binary logit specification. It uses heterogeneous mean of the random parameter across households to capture shadow evacuation. It is found that the likelihood of evacuation for households that do not receive any evacuation notice decreases as their distance to coast increase on average. The distance sensitivity factor, or DSF, is introduced to construct the different scenarios of geographical extent of shadow evacuation. The dissertation then conducts statistical analysis of the vehicle usage choice. It identifies the contributing factors to households' choice of the number of vehicles used for evacuation and develop predictive models of this choice that explicitly consider the constraint imposed by the number of vehicles owned by the household. This constraint is not accommodated by ordered response models. Data comes from a post-storm survey for Hurricane Ivan. The two models developed are variants of the regular Poisson regression model: the Poisson model with exposure and right-censored Poisson regression. The right-censored Poisson model is preferred due to its inherent capabilities, better fit to the data, and superior predictive power. The multivariable model and individual variable analyses are used to investigate seven hypotheses. Households traveling longer distances or evacuating later are more likely to use fewer vehicles. Households with prior hurricane experience, greater numbers of household members between 18 and 80, and pet owners are more likely to use a greater number of vehicles. Income and distance from the coast are insignificant in the multivariable models, although their individual effects have statistically significant linear relationship. However, the Poisson based models are non-linear. The method for using the right-censored Poisson model for producing the desired share of vehicle usage is also provided for the purpose of generating individual predictions for simulation. The dissertation then presents a descriptive analysis of and econometric models for households' pre-evacuation activities based on behavioral intention data collected for Miami Beach, Florida. The descriptive analysis shows that shopping - particularly food, gasoline, medicine, and cash withdrawal - accounts for the majority of preparation activities, highlighting the importance of maintaining a supply of these items. More than 90% of the tours are conducted by driving, emphasizing the need to incorporate pre-evacuation activity travel into simulation studies. Households perform their preparation activities early in a temporally concentrated manner and generally make the tours during daylight. Households with college graduates, larger households, and households who drive their own vehicles are more likely to engage in activities that require travel. The number of household members older than 64 has a negative impact upon engaging in out-of-home activities. An action day choice model for the first tour suggests that households are more likely to buy medicine early but are more likely to pick up friends/relatives late. Households evacuating late are more likely to conduct their activities late. Households with multiple tours tend to make their first tour early. About 10% of households chain their single activity chains with their ultimate evacuation trips. The outcomes of this paper can be used in demand generation for traffic simulations. The dissertation finally uses the behavioral findings and develops an agent-based travel demand model system for hurricane evacuation simulation, which is capable of generating the comprehensive household activity-travel plans. The system implements econometric and statistical models that represent travel and decision-making behavior throughout the evacuation process. The system considers six typical evacuation decisions: evacuate-stay, accommodation type choice, evacuation destination choice, mode choice, vehicle usage choice and departure time choice. It explicitly captures the shadow evacuation population. In addition, the model system captures the pre-evacuation preparation activities using an activity-based approach. A demonstration study that predicts activity-travel patterns using model parameters estimated for the Miami-Dade area is discussed. The simulation results clearly indicate the model system produced the distribution of choice patterns that is consistent with sample observations and existing literature. The model system also identifies the proportion of the shadow evacuation population and their geographical extent. About 23% of the population outside the designated evacuation zone would evacuate. The shadow evacuation demand is mainly located within 3.1 miles (5 km) of the coastline. The output demand of the model system works with agent-based traffic simulation tools and conventional trip-based simulation tools. The agent-based travel demand model system is capable of generating activity plans that works with agent-based traffic simulation tools and conventional trip-based simulation tools. It will facilitate the hurricane evacuation management. / Ph. D.

This thesis provides insight into quantitative accuracy assessment of the modeling and simulation of power electronic converters. Verification, Validation, and Uncertainty quantification (VVandUQ) provides a means to quantify the disagreement between computational simulation results and experimental results in order to have quantitative comparisons instead of qualitative comparisons. Due to the broad applications of modeling and simulation in power electronics, VVandUQ is used to evaluate the credibility of modeling and simulation results. The topic of VVandUQ needs to be studied exclusively for power electronic converters. To carry out this work, the formal procedure for VVandUQ of power electronic converters is presented. The definition of the fundamental words in the proposed framework is also provided. The accuracy of the switching model of a three-phase Voltage Source Inverter (VSI) is quantitatively assessed following the proposed procedure. Accordingly, this thesis describes the hardware design and development of the switching model of the three-phase VSI. / Master of Science

A comprehensive evaluation of roll and yaw stability of tractor/semitrailers with single and dual trailers in city and highway conditions is conducted. Commercial vehicles fundamentally behave differently in city driving conditions than at high speeds during highway driving conditions. In order to closely examine each, this study offers two distinct evaluations of commercial vehicles: 1) low-speed driving in tight turns, representative of city driving; and 2) high-speed lane change and evasive maneuvers, typical of highway driving. Specifically, for city driving, the geometric parameters of the roadway in places where tight turns occur—such as in roundabouts—are closely examined in a simulation study in order to evaluate the elements that could cause large vehicle body lean (or high rollover index), besides the truck elements that have most often been studied. Two roundabout geometries, 140-ft single-lane and a 180-ft double-lane, are examined for various truck load conditions and configurations. The vehicle configurations that are considered are a straight 4x2 truck, a tractor with a 53-ft semi-trailer (commonly known as WB-67), and two trucks in double-trailer configurations. Five potential factors are identified and thoroughly studied: circulatory roadway cross-section, roundabout tilt, truck configurations, truck apron geometry, and truck load condition. The results of the study indicate that when the rear axles of the trailer encounter the truck apron in the roundabout, the climbing and disembarking action can cause wheel unloading on the opposite side, therefore significantly increasing the risk of rollover. Interestingly, in contrast to most high-speed rollovers that happen with fully-loaded trailers, at low speeds, the highest risks are associated with lightly loaded or unloaded trucks. For high-speed driving conditions, typical of highway driving, a semi-truck with a double 28-ft trailer configuration is considered, mainly due to its increasing use on U.S. roads. The effect of active safety systems for commercial vehicles, namely Roll Stability Control (RSC) for trailers and Electronic Stability Control (ESC) for the tractor, is closely examined in a test study. Various trailer loading possibilities are evaluated for different combinations of ESC/RSC on the tractor and trailer, respectively. The results of the study indicate that 1) RSC systems reduce the risk of high-speed rollovers in both front and rear trailers, 2) the combination of ESC (on tractor) and RSC (on trailer) reduce the risk of rollover and jackknifing, and 3) RSC systems perform less effectively when the rear trailer is empty. / PHD

The typical preparation plant producing coal for the utility market targets a relative separation density in the plant of around 1.60 whereas plants generating metallurgical coal use relative cut point density values approaching 1.50. In some cases, achieving the specified coal quality requires operating at lower cut point values, which results in a significant loss of valuable coal. In these situations, a middlings stream can be produced using a secondary separator or a three-product unit, which would allow crushing of the middlings for liberation purposes and re-introduction into the plant feed. In this manner, higher quality coal can be produced while maximizing plant yield. A detailed laboratory analysis was conducted to study the liberation characteristics resulting from the crushing of middlings at different top sizes. The experimental data were later used as input for modeling and simulation of plant flowsheet in LIMN. Simulations were run for several regrinding cases. The results of the current study investigating the economic benefits of middlings liberation and re-treatment are presented and discussed in this thesis. Improvement up to 6% in plant yield with 16-21% reduction in ash and 14-18% sulfur reductions can be achieved by crushing the +1/2 inch middlings to a ½-inch top size.

La modélisation et la spécification de systèmes distribués nécessitent une adaptation des modèles logiques utilisés pour leur représentation. Les notions<br />d'emplacements et de ressources jouent notamment un rôle centrale dans la représentation de ces systèmes.<br /><br />On propose tout d'abord à la proposition d'une première logique, la logique linéaire distribuée et mobile (DMLL) qui intègre les notions de distribution et de mobilité. On propose également une sémantique à la Kripke et un calcul des séquents supportant l'élimination des coupures pour cette logique.<br /><br />Cette première étude a mis en avant le rôle centrale de la sémantique pour la modélisation de systèmes distribués. On propose alors la structure des arbres de ressources, des arbres dont les noeuds possèdent des labels et contiennent des ressources appartenant à<br />monoïde partiel de ressources et BI-Loc, une logique pour raisonner sur ces arbres, un langage permettant de modifier les arbres et son axiomatisation correcte et complète sous forme de triplets de Hoare. Concernant BI-Loc, on détermine des conditions suffisantes pour décider de la satisfaction et de la validité par model-checking et on développe une méthode de preuves fondée sur les tableaux sémantiques correcte et complète.<br /><br />On montre comment on peut raisonner sur les tas de pointeurs grâce aux arbres de ressources. Enfin, on détermine comment le modèle des arbres partiel peut être utilisé pour représenter et spécifier les données<br />semi-structurées et raisonner sur la transformation de ce type de données.

Les prochaines générations de terminaux mobiles devront être capables, de façon autonome, de déterminer au fil des déplacements de l'utilisateur, les standards de communication les plus adaptés pour garantir un niveau de qualité de service satisfaisant pour les applications en cours de fonctionnement. Ces systèmes proposeront de plus une gamme étendue de standards de communication et une offre diversifiée d'applications. Pour intégrer toutes ces fonctionnalités en respectant les contraintes fortes en termes de coût, de consommation et de surface associées à ces systèmes, de nouvelles architectures composées d'un ensemble de ressources hétérogènes et flexibles devront être dimensionnées. Pour correctement dimensionner de telles architectures en respectant des délais de conception de plus en plus courts, des évolutions vont devoir être envisagées afin d'améliorer la productivité des architectes systèmes. La tendance constatée consiste à favoriser la définition de modèles permettant d'évaluer très tôt dans le processus de conception les performances pouvant être obtenues pour différentes solutions d'implantation envisageables. Ces modèles doivent être définis avec un niveau de description permettant une évaluation efficace de l'espace de conception. Le niveau transactionnel intégrant des propriétés temporelles apparaît actuellement comme une solution intéressante pour répondre à ce nouveau besoin. Cependant l'absence de méthodes claires et précises pour la définition de modèles à ce niveau d'abstraction ne facilite pas encore son adoption dans le domaine industriel. Les travaux de recherche présentés dans cette thèse visent donc à tirer parti des possibilités offertes par le concept de modélisation transactionnelle (TLM) pour réaliser le dimensionnement des futurs terminaux mobiles. Notre travail a porté sur la proposition d'une démarche devant guider l'architecte système jusqu'à la définition précise des ressources matérielles et logicielles satisfaisant aux exigences imposées par ces systèmes. Cette démarche repose sur un ensemble d'étapes pour la création de modèles exécutables de niveau transactionnel. L'originalité de ces travaux réside dans la possibilité de pouvoir représenter au sein d'un même modèle de niveau transactionnel les propriétés fonctionnelles et non fonctionnelles d'un système à dimensionner. Un modèle d'exécution générique a été proposé de manière à faciliter la définition d'instances de modèles décrivant les différentes solutions architecturales à évaluer. L'environnement de modélisation proposé par l'outil CoFluent Studio a été utilisé pour capturer ces modèles afin de générer les modèles SystemC associés. En utilisant l'environnement de simulation proposé par cet outil, il est alors possible d'exécuter le modèle obtenu afin d'observer les performances de l'architecture analysée en appliquant différents types de paramétrage possibles. Pour limiter les temps de simulation nécessaires à l'obtention de résultats, une technique de calcul des propriétés non fonctionnelles a aussi été proposée. Elle permet de diminuer le nombre de transactions devant être initiées lors de la simulation du modèle SystemC ce qui entraine une réduction significative des temps de simulation. L'intérêt de nos travaux a été illustré à travers deux expérimentations. La première concernait le dimensionnement des ressources nécessaires à la mise en œuvre des traitements de la couche physique du futur standard de communication LTE. Les modèles obtenus offrent la possibilité d'évaluer les puissances de calcul et les ressources de mémorisation requises par différentes solutions architecturales et ce selon les différents paramétrages possibles de la couche physique. La deuxième expérimentation a été menée dans le cadre du dimensionnement d'un terminal mobile représentatif des nouveaux besoins applicatifs évoqués. Le travail de modélisation effectué a permis de définir dans un premier temps une description exécutable de niveau transactionnel du système permettant d'observer son comportement en fonction des nombreux scénarios de fonctionnement envisageables. Ce modèle a ensuite été utilisé pour dimensionner les ressources nécessaires à la réalisation de la fonction de décodage canal associée aux deux standards de communication supportés.

Les contraintes sont un moyen générique de représenter les règles qui gouvernent notre monde. Étant donné un ensemble de contraintes, une question centrale est de savoir s'il existe une possibilité de toutes les satisfaire simultanément. Cette problématique est au cœur de la programmation par contraintes, un paradigme puissant pour résoudre efficacement des problèmes qui apparaissent dans de nombreux domaines de l'activité humaine. Initialement dédiée, dans les années 1980, à la résolution de problèmes d'intelligence artificielle à variables entières, c'est dans les années 1990 que la programmation par contraintes a été employée à la résolution de problèmes à variables réelles. Cependant, les problèmes mixtes —utilisant à la fois variables entières et réelles— n'ont été que très peu considérés jusqu'ici par la programmation par contraintes. Dans cette thèse, nous nous plaçons du point de vue de la résolution de problèmes continus. Nous proposons et mettons en oeuvre différentes améliorations de ce cadre de résolution : • Intégration de la notion de recherche rigoureuse d'optimum au cadre classique de résolution sans objectif, afin de modéliser et résoudre un problème de conception en robotique ; • Collaboration de deux solveurs, l'un discret l'autre continu, plus efficace que chacun des outils pour résoudre les problèmes utilisant contraintes continues et contraintes discrètes ; • Comparaison des différentes modélisations et filtrages possibles de la contrainte globale discrète alldifferent, permettant de l'utiliser dans un solveur dédié au continu ; • Spécialisation des techniques de filtrage basées sur l'arithmétique des intervalles, augmentant la puissance de filtrage des contraintes arithmétiques discrètes et mixtes.