Ces dernières années, l’émergence des nouvelles technologies tels que la miniaturisation des composants, les dispositifs de communication sans fils, l’augmentation de la taille de stockage et les capacités de calcul, a permis la conception de systèmes multi-agents coopératifs de plus en plus complexes. L’un des plus grands axes de recherche dans cette thématique concerne la commande en formation de flottes de véhicules autonomes. Un grand nombre d’applications et de missions, civiles et militaires, telles que l’exploration, la surveillance, et la maintenance, ont alors été développées et réalisées dans des milieux variés (terre, air, eau). Durant l’exécution de ces tâches, les véhicules doivent interagir avec leur environnement et entre eux pour se coordonner. Les outils de communication disponibles disposent souvent d’une portée limitée. La préservation de la connexion au sein du groupe devient alors un des objectifs à satisfaire pour que la tâche puisse être accomplie avec succès. Une des possibilités pour garantir cette contrainte est le déplacement en formation permettant de préserver les distances et la structure géométrique du groupe. Il est toutefois nécessaire de disposer d’outils et de méthodes d’analyse et de commande de ces types de systèmes afin d’exploiter au maximum leurs potentiels. Cette thèse s’inscrit dans cette direction de recherche en présentant une synthèse et une analyse des systèmes dynamiques multi-agents et plus particulièrement la commande en formation de véhicules autonomes. Les lois de commande développées dans la littérature pour la commande en formation permettent d’accomplir un grand nombre de missions avec un niveau de performance élevé. Toutefois, si un défaut/défaillant apparaît dans la formation, ces lois de commandes peuvent s’avérer très limitées, engendrant un comportement instable du système. Le développement de commandes tolérantes aux défauts devient alors primordial pour maintenir les performances de commande en présence de défauts. Cette problématique sera traitée dans ce mémoire de thèse et concernera le développement et la conception de commandes en formation tolérantes au défaut dévolu à une flotte de véhicules autonomes suivant différente configuration/structuration / In recent years, the emergence of new technologies such as miniaturization of components, wireless communication devices, increased storage size and computing capabilities have allowed the design of increasingly complex cooperative multi-agent systems. One of the main research axes in this topic concerns the formation control of fleets of autonomous vehicles. Many applications and missions, civilian and military, such as exploration, surveillance, and maintenance, were developed and carried out in various environments. During the execution of these tasks, the vehicles must interact with their environment and among themselves to coordinate. The available communication tools are often limited in scope. The preservation of the connection within the group then becomes one of the objectives to be satisfied in order to carry out the task successfully. One of the possibilities to guarantee this constraint is the training displacement, which makes it possible to preserve the distances and the geometrical structure of the group. However, it is necessary to have tools and methods for analyzing and controlling these types of systems in order to make the most of their potential. This thesis is part of this research direction by presenting a synthesis and analysis of multi-agent dynamical systems and more particularly the formation control of autonomous vehicles. The control laws developed in the literature for formation control allow to carry out a large number of missions with a high level of performance. However, if a fault/failure occurs in the training, these control laws can be very limited, resulting in unstable system behavior. The development of fault tolerant controls becomes paramount to maintaining control performance in the presence of faults. This problem will be dealt with in more detail in this thesis and will concern the development and design of Fault tolerant controls devolved to a fleet of autonomous vehicles according to different configuration/structuring

This research addresses fleet-sizing for reusable containers that are used for protection, transportation, and storage of parts between a component plant and assembly plant. These reusable containers are often expensive and occupy a large amount of storage space when empty and full. Having a large container fleet comes with higher acquisition, maintenance, and storage costs, but decreases production down time caused by the lack of containers needed for storage. A quantitative model of these trade-offs will permit decision makers to maintain desired production levels at minimum cost. In this dissertation, the relationship between container fleet size and production down time caused by container shortages is researched. Utilizing both theoretical and empirical approaches, two analytical models that include relevant operational parameters and stochastic components are developed. The first is a container fleet sizing model, and the second model estimates production stoppages as a function of container fleet size. The formulas are shown to be accurate and provide decision makers with the tools to better plan and manage specific applications. The formulas also provide general insight into the factors that affect container fleet size and production stoppage due to container shortages. / Graduation date: 2012

<p>De svenska sjöoperativa helikoptersystemen såg sitt ljus för första gången på 1950-talet. Sedan denna pionjärålder har dessa system varit en del av den svenska marina krigföringen. Men vilken påverkan har de i realiteten haft på denna krigföring och hur har den svenska taktiken påverkats av helikoptersystemen?  Syftet med denna uppsats är att är utröna detta genom att belysa tre årtionden som har varit av stor vikt för det svenska marinflyget: 1960-talet, 1980-talet samt 2000-talet.</p><p>För att lättare påvisa vilken effekt dessa system har haft på den svenska marina krigföringen så utgår denna uppsats ur den teori som inom krigsvetenskapen kallas för kombinerad bekämpning. Denna teori behandlar de fenomen och fördelar som uppstår då flera vapensystem och/eller vapenslag kombineras för att uppnå en synergieffekt på slagfältet. Vinsten med denna synergieffekt är att befälhavaren lättare kan behålla initiativet och har fler valmöjligheter vid bekämpandet av en fiende. De egna sidans styrka skall i största möjliga mån ställas mot fiendens svagheter. </p><p> Uppsatsen visar på att under de specifika årtiondena har de sjöoperativa helikoptersystemen haft en stor betydelse för den svenska marina krigföringen och då framförallt inom området ubåtsjakt. Resultatet av studien visar vidare på att den påverkan som dessa system har haft på krigföringen varierar mellan de olika årtiondena med 1980-talet som de årtionde där påverkan har varit som störst. Tongivande för uppsatsen har varit den ubåtsjakt som bedrivits under de specifika årtiondena men den studie som genomförts i uppsatsen har även belyst andra områden som de sjöoperativa helikoptrarna har påverkat såsom transport, havsövervakning och ytmålspaning. Dock har påverkan här visat sig vara mindre än inom området ubåtsjakt.</p> / <p>The purpose of this study is to examine to what extent the Royal Swedish Navy Fleet Air Arm (RSNFAA), and more specifically the helicopters assigned to this weapons branch, has effected Swedish naval warfare tactics during three separate decades: namely the 1960´s 1980´s and 2000´s.  </p><p>The study takes its starting point in the theories that war science referrers to as combined arms.</p><p>The characteristics of the combined arms theory are to combine different weapon systems and weapon branches to conquer the enemy by attacking his weak spots. By combining weapon systems the commander in question will minimize his own weaknesses on the battlefield and therefore gain the upper hand on the enemy. </p><p>This theory gives a good theoretical view when analyzing which impact the Sea based operations- helicopters (SBO) have had during the specific decades that are being examined due to its ability to be applied on both land and naval forces.</p><p>Literature on the combined arms theory as well as historical documents over these three decades constitutes the main sources which have been used to carry out the study.</p><p>The result of the study shows that the implementing SBO-helicopters in the Swedish naval warfare tactics have had a major effect and more specifically in the AntiSubmarine Warfare (ASuW) area.</p>

De svenska sjöoperativa helikoptersystemen såg sitt ljus för första gången på 1950-talet. Sedan denna pionjärålder har dessa system varit en del av den svenska marina krigföringen. Men vilken påverkan har de i realiteten haft på denna krigföring och hur har den svenska taktiken påverkats av helikoptersystemen?  Syftet med denna uppsats är att är utröna detta genom att belysa tre årtionden som har varit av stor vikt för det svenska marinflyget: 1960-talet, 1980-talet samt 2000-talet. För att lättare påvisa vilken effekt dessa system har haft på den svenska marina krigföringen så utgår denna uppsats ur den teori som inom krigsvetenskapen kallas för kombinerad bekämpning. Denna teori behandlar de fenomen och fördelar som uppstår då flera vapensystem och/eller vapenslag kombineras för att uppnå en synergieffekt på slagfältet. Vinsten med denna synergieffekt är att befälhavaren lättare kan behålla initiativet och har fler valmöjligheter vid bekämpandet av en fiende. De egna sidans styrka skall i största möjliga mån ställas mot fiendens svagheter.   Uppsatsen visar på att under de specifika årtiondena har de sjöoperativa helikoptersystemen haft en stor betydelse för den svenska marina krigföringen och då framförallt inom området ubåtsjakt. Resultatet av studien visar vidare på att den påverkan som dessa system har haft på krigföringen varierar mellan de olika årtiondena med 1980-talet som de årtionde där påverkan har varit som störst. Tongivande för uppsatsen har varit den ubåtsjakt som bedrivits under de specifika årtiondena men den studie som genomförts i uppsatsen har även belyst andra områden som de sjöoperativa helikoptrarna har påverkat såsom transport, havsövervakning och ytmålspaning. Dock har påverkan här visat sig vara mindre än inom området ubåtsjakt. / The purpose of this study is to examine to what extent the Royal Swedish Navy Fleet Air Arm (RSNFAA), and more specifically the helicopters assigned to this weapons branch, has effected Swedish naval warfare tactics during three separate decades: namely the 1960´s 1980´s and 2000´s.   The study takes its starting point in the theories that war science referrers to as combined arms. The characteristics of the combined arms theory are to combine different weapon systems and weapon branches to conquer the enemy by attacking his weak spots. By combining weapon systems the commander in question will minimize his own weaknesses on the battlefield and therefore gain the upper hand on the enemy.  This theory gives a good theoretical view when analyzing which impact the Sea based operations- helicopters (SBO) have had during the specific decades that are being examined due to its ability to be applied on both land and naval forces. Literature on the combined arms theory as well as historical documents over these three decades constitutes the main sources which have been used to carry out the study. The result of the study shows that the implementing SBO-helicopters in the Swedish naval warfare tactics have had a major effect and more specifically in the AntiSubmarine Warfare (ASuW) area.

The expected rise in aviation demand requires the reduction of the environmental impacts that impede this desired growth, such as fuel burn, emissions, and airport noise. A number of current technology programs attempt to identify, evaluate, and select the environmental technology solutions for the coming decades. Fleet-level evaluation will be essential to deciding between various technology options because it provides a system-level assessment that clarifies the effect of operational and policy variables. Fleet-level modeling in general, introduces various complexities, and detailed fleet-level models require significant time and computing resources to execute. With a large number of potential technology options available for assessment, a full detailed analysis of the technology space is infeasible. Therefore, a simplified fleet-level environmental evaluation methodology is required to select scenarios to carry forward for detailed modeling. Capabilities such as the Global and Regional Environmental Aviation Tradeoff (GREAT) tool, have achieved rapid simplified fleet-level analysis for fuel burn and emissions, but currently lack a satisfactory generic framework to evaluate fleet-level noise. The primary objective of this research is to formulate and implement a generic fleet-level noise methodology that allows decision makers to analyze the fleet-level impact of many technology scenarios on the quantity of noise, and also its distribution about certain airport types. This information can be leveraged to provide screening assessments of technology impacts earlier in the decision-making process, reserving more sophisticated modeling techniques for the most promising scenarios. The capability gaps identified are addressed by the development of a rapid generic fleet-level noise model that captures basic airport noise contour shape and contour area, a categorization of airports with respect to their operational and infrastructure characteristics, and the development of shape metrics that enable rapid classification and comparison of contour shapes. Once the capability gaps were addressed, the resultant System-Wide Assessment of Noise (SWAN) methodology was implemented via use cases to demonstrate the application of the methodology, examining the introduction of a set of possible near-term (N+1) future technologies into the forecast. While these examples are simplified and notional, they demonstrate the types of analyses and investigations that can be performed with the SWAN methodology, providing answers regarding the impact of technologies on contour shapes. The development, verification, validation, and demonstration of these capabilities complete a framework for evaluating fleet-level noise at the screening-level that retains the ability to capture and effectively discuss shape information beyond the capability of current screening-level noise evaluation techniques. By developing a rapid generic fleet-level noise model, a set of Generic Airports, and metrics that objectively quantify and describe shape, decision-makers can access greater levels of information, including the critical facet of contour shape in fleet-level airport noise.

The first part of this thesis relies on stated and revealed preference survey results across a sample of U.S. households to first ascertain vehicle acquisition, disposal, and use patterns, and then simulate these for a synthetic population over time. Results include predictions of future U.S. household-fleet composition, use, and greenhouse gas (GHG) emissions under nine different scenarios, including variations in fuel and plug-in-electric-vehicle (PHEV) prices, new-vehicle feebate policies, and land-use-density settings. The adoption and widespread use of plug-in vehicles will depend on thoughtful marketing, competitive pricing, government incentives, reliable driving-range reports, and adequate charging infrastructure. This work highlights the impacts of various directions consumers may head with such vehicles. For example, twenty-five-year simulations at gas prices at $7 per gallon resulted in the highest market share predictions (16.30%) for PHEVs, HEVs, and Smart Cars (combined) — and the greatest GHG-emissions reductions. Predictions under the two feebate policy scenarios suggest shifts toward fuel-efficient vehicles, but with vehicle miles traveled (VMT) rising slightly (by 0.96% and 1.42%), thanks to lower driving costs. The stricter of the two feebate policies – coupled with gasoline at $5 per gallon – resulted in the highest market share (16.37%) for PHEVs, HEVs, and Smart Cars, but not as much GHG emissions reduction as the $7 gas price scenario. Total VMT values under the two feebate scenarios and low-PHEV-pricing scenarios were higher than those under the trend scenario (by 0.56%, 0.96%, and 1.42%, respectively), but only the low-PHEV-pricing scenario delivered higher overall GHG emission estimates (just 0.23% more than trend) in year 2035. The high-density scenario (where job and household densities were quadrupled) resulted in the lowest total vehicle ownership levels, along with below-trend VMT and emissions rates. Finally, the scenario involving a $7,500 rebate on all PHEVs still predicted lower PHEV market share than the $7 gas price scenario (i.e., 2.85% rather than 3.78%). The second part of this thesis relies on data from the U.S. Consumer Expenditure Survey (CEX) to estimate the welfare impacts of carbon taxes and household-level capping of emissions (with carbon-credit trading allowed). A translog utility framework was calibrated and then used to anticipate household expenditures across nine consumer goods categories, including vehicle usage and vehicle expenses. An input-output model was used to estimate the impact of carbon pricing on goods prices, and a vehicle choice model determined vehicle type preferences, along with each household’s effective travel costs. Behaviors were predicted under two carbon tax scenarios ($50 per ton and $100 per ton of CO2-equivalents) and four cap-and-trade scenarios (10-ton and 15-ton cap per person per year with trading allowed at $50 per ton and $100 per ton carbon price). Results suggest that low-income households respond the most under a $100-per-ton tax but increase GHG emissions under cap-and-trade scenarios, thanks to increased income via sale of their carbon credits. High-income households respond the most across all the scenarios under a 10-ton cap (per household member, per year) and trading at $100 per ton scenario. Highest overall emission reduction (47.2%) was estimated to be under $100 per ton carbon tax. High welfare loss was predicted for all households (to the order of 20% of household income) under both the policies. Results suggest that a carbon tax will be regressive (in terms of taxes paid per dollar of expenditure), but a tax-revenue redistribution can be used to offset this regressivity. In the absence of substitution opportunities (within each of the nine expenditure categories), these results represent highly conservative (worst-case) results, but they illuminate the behavioral response trends while providing a rigorous framework for future work. / text

The objectives of this study are to measure the non-methane volatile organic carbon (NMVOC&#039 / s) emissions from passenger cars in Turkey having gasoline engines, to determine emission factors of these vehicles for BTEX compounds and comparison of emission factors obtained in this study with the emission factors of the other countries. This study was conducted in two parts: The first part was to determine the categories of passenger cars widely used in Turkey, and also to determine the average carbon monoxide (CO) and hydrocarbon (HC) emissions at idle condition for these car types based on the exhaust emission measurements of Ankara &Ccedil / evre Koruma Vakfi (AN&Ccedil / EVA). The second part of the study was to analyze the gas composition of exhaust gasses at different road conditions for BTEX components by using gas chromatography. The results of the study have shown that the cars named under &lsquo / &lsquo / Tofas&rsquo / &rsquo / constitute 31.5% and &lsquo / &lsquo / Fiat&rsquo / &rsquo / 13.1% of the total cars in Turkey and they are manufactured by the same company. Therefore, studies have been performed with &lsquo / &lsquo / Tofas/Fiat&rsquo / &rsquo / cars. The highest emission factors among hydrocarbons investigated in this study were found for toluene and m-xylene. Generally, as driving speed increases the emissions of HC&rsquo / s are found to decrease in concentration. It was interesting to note that the highest emissions occur at 30 km/hr speed which is the mostly used speed in crowded streets and busy intersections. Therefore, it was concluded that it is very important to take measures for emissions in the city traffic. Cold start emissions were also found to be higher than the hot start emissions.

This dissertation consists of two self-contained studies. The first study, in the domain of stochastic inventory theory, addresses the structure of optimal ordering policies in a periodic review setting. We take multiple sources of a single product to imply an ordering cost function that is nondecreasing, piecewise linear, and convex. Our main contribution is a proof of the optimality of a finite generalized base stock policy under an average cost criterion. Our inventory model is formulated as a Markov decision process with complete observations. Orders are delivered immediately. Excess demand is fully backlogged, and the function describing holding and backlogging costs is convex. All parameters are stationary, and the random demands are independent and identically distributed across periods. The (known) distribution function is subject to mild assumptions along with the holding and backlogging cost function. Our proof uses a vanishing discount approach. We extend our results from a continuous environment to the case where demands and order quantities are integral. The second study is in the area of capacity planning. Our overarching contribution is a relatively simple and fast solution approach for the fleet composition problem faced by a retail distribution firm, focusing on the context of a major beverage distributor. Vehicles to be included in the fleet may be of multiple sizes; we assume that spot transportation capacity will be available to supplement the fleet as needed. We aim to balance the fixed costs of the fleet against exposure to high variable costs due to reliance on spot capacity. We propose a two-stage stochastic linear programming model with fixed recourse. The demand on a particular day in the planning horizon is described by the total quantity to be delivered and the total number of customers to visit. Thus, daily demand throughout the entire planning period is captured by a bivariate probability distribution. We present an algorithm that efficiently generates a "definitive" collection of bases of the recourse program, facilitating rapid computation of the expected cost of a prospective fleet and its gradient. The equivalent convex program may then be solved by a standard gradient projection algorithm.

The aim of this work is to analyze individual malt technologies according to their use for beverages storing in Elko limited warehouse, then suggesting optimal alternative in terms of time and cost demands of establishing and running the warehouse. The main factor when choosing optimum in-store technology and service means is the fact, that Elko company stores a high turnover ratio material, which is necessary to complete for almost every order. For this reason, the warehouse either has to have a room sufficiently big for completing orders, or an option of completing the orders right in the store core. Sub-objectives were to prepare the legislative framework of the work, to assess the processes in the enterprise, assess and propose improvements to the stock.

Made available in DSpace on 2016-06-02T19:06:14Z (GMT). No. of bitstreams: 1 6183.pdf: 2878708 bytes, checksum: f9bc336337651cbba67af52d8acb7ec2 (MD5) Previous issue date: 2014-06-10 / Financiadora de Estudos e Projetos / Vehicle fleets are an important component in several applications, moving materials and people. Examples include material handling in warehouses, factories and port terminals, people transportation as in taxi fleets and emergency services, such as medical assistance, fire-fighters and police. Fleet operation is crucial for these applications: it can mean loss of money and commercial partners in case of industry, os loss of lives in case of emergency services. Controlling the fleet to achieve efficient levels of performance is a difficult problem, though, and becomes even harder as the fleet grows. Research in the area has been linking vehicle fleet operation to Multi-Agent Systems, because vehicle fleets are naturally distributed and Multi-agent System is a convenient abstraction to cope with distributed Artificial Intelligence problems. Therefore, it is proposed a Multi-Agent System to control vehicle fleets, focusing on material handling application in warehouses. The proposed system has three types of agents: Vehicle Agent, Loading Point Agent and Storage Point Agent. Agents interact amongst themselves through messages, trying to efficiently realize the material handling in a warehouse. System implementation is done through a simulation of a warehouse operation, built on top of MASON multi-agent system simulation platform. Task assignment strategies is also an important problem, therefore four strategies are shown and tested using the simulation: CNET, Fuzzy, DynCNET and FiTA. To enable comparison among these strategies, a Genetic Algorithm is employed to systematically search good parameters for each strategy. The proposed system, as well as the simulation, are offered as a framework for development of other vehicle fleets controlling multi-agent systems and/or task assignment strategies. / Em várias aplicações, frotas de veículos são um componente importante, transportando materiais e pessoas. Exemplos incluem o manejo de materiais em depósitos, fabricas e terminais portuários, o transporte de pessoas como em frotas de taxis e serviços de emergência, como socorro medico, bombeiros e polícia. A operacao da frota e crucial para essas aplicações: pode significar perda de dinheiro e parceiros comerciais no caso dos exemplos na indústria, ou perda de vidas, no caso de serviços de emergência. Porem, controlar a frota de modo que ela opere eficientemente e um problema difícil, que se torna ainda mais custoso com o aumento da frota. Pesquisas na área tem ligado a operação de frotas de veículos a Sistema Multiagente, notando os fatos de que frotas de veículos são naturalmente distribuídas e que o conceito de Agentes (e, consequentemente, Sistemas Multiagentes) e uma abstração conveniente para lidar com problemas de Inteligencia Artificial de forma distribuída. Com base nisto, e proposto um Sistema Multiagente para controle de frotas de veículos, focando a aplicação dessa frota no manejo de materiais em um depósito. O sistema proposto possui três tipos agentes: Agente de Veículo, Agente de Ponto de Carga e Agente de Ponto de Armazenamento. Os agentes interagem entre si, trocando mensagens a fim de realizar o manejo dos materiais no deposito de forma eficiente. O sistema e implementado na forma de uma simulação de operação de um deposito, construída na plataforma de simulação de sistemas multiagentes MASON. Como a estrategia de associação de tarefas também e um problema importante, quatro estratégias são mostradas e testadas através da simulação: CNET, Fuzzy, DynCNET e FiTA. Para possibilitar comparações entre as estrategias, um Algoritmo Genetico foi utilizado para sistematicamente encontrar bons parâmetros para as quatro estrategias. O sistema proposto, bem como a simulação, são oferecidos como framework para construção de outros sistemas multiagentes para frotas de veículos e/ou estrategias de associação de tarefas.