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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Microscopic Assessment Of Transportation Emissions On Limited Access Highways

Abou-Senna, Hatem 01 January 2012 (has links)
On-road vehicles are a major source of transportation carbon dioxide (CO2) greenhouse gas emissions in all the developed countries, and in many of the developing countries in the world. Similarly, several criteria air pollutants are associated with transportation, e.g., carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM). The need to accurately quantify transportation-related emissions from vehicles is essential. Transportation agencies and researchers in the past have estimated emissions using one average speed and volume on a long stretch of roadway. With MOVES, there is an opportunity for higher precision and accuracy. Integrating a microscopic traffic simulation model (such as VISSIM) with MOVES allows one to obtain precise and accurate emissions estimates. The new United States Environmental Protection Agency (USEPA) mobile source emissions model, MOVES2010a (MOVES) can estimate vehicle emissions on a second-by-second basis creating the opportunity to develop new software ―VIMIS 1.0‖ (VISSIM/MOVES Integration Software) to facilitate the integration process. This research presents a microscopic examination of five key transportation parameters (traffic volume, speed, truck percentage, road grade and temperature) on a 10-mile stretch of Interstate 4 (I- 4) test bed prototype; an urban limited access highway corridor in Orlando, Florida. iv The analysis was conducted utilizing VIMIS 1.0 and using an advanced custom design technique; D-Optimality and I-Optimality criteria, to identify active factors and to ensure precision in estimating the regression coefficients as well as the response variable. The analysis of the experiment identified the optimal settings of the key factors and resulted in the development of Micro-TEM (Microscopic Transportation Emissions MetaModel). The main purpose of Micro-TEM is to serve as a substitute model for predicting transportation emissions on limited access highways in lieu of running simulations using a traffic model and integrating the results in an emissions model to an acceptable degree of accuracy. Furthermore, significant emission rate reductions were observed from the experiment on the modeled corridor especially for speeds between 55 and 60 mph while maintaining up to 80% and 90% of the freeway‘s capacity. However, vehicle activity characterization in terms of speed was shown to have a significant impact on the emission estimation approach. Four different approaches were further examined to capture the environmental impacts of vehicular operations on the modeled test bed prototype. First, (at the most basic level), emissions were estimated for the entire 10-mile section ―by hand‖ using one average traffic volume and average speed. Then, three advanced levels of detail were studied using VISSIM/MOVES to analyze smaller links: average speeds and volumes (AVG), second-bysecond link driving schedules (LDS), and second-by-second operating mode distributions (OPMODE). This research analyzed how the various approaches affect predicted emissions of CO, NOx, PM and CO2. v The results demonstrated that obtaining accurate and comprehensive operating mode distributions on a second-by-second basis improves emission estimates. Specifically, emission rates were found to be highly sensitive to stop-and-go traffic and the associated driving cycles of acceleration, deceleration, frequent braking/coasting and idling. Using the AVG or LDS approach may overestimate or underestimate emissions, respectively, compared to an operating mode distribution approach. Additionally, model applications and mitigation scenarios were examined on the modeled corridor to evaluate the environmental impacts in terms of vehicular emissions and at the same time validate the developed model ―Micro-TEM‖. Mitigation scenarios included the future implementation of managed lanes (ML) along with the general use lanes (GUL) on the I-4 corridor, the currently implemented variable speed limits (VSL) scenario as well as a hypothetical restricted truck lane (RTL) scenario. Results of the mitigation scenarios showed an overall speed improvement on the corridor which resulted in overall reduction in emissions and emission rates when compared to the existing condition (EX) scenario and specifically on link by link basis for the RTL scenario. The proposed emission rate estimation process also can be extended to gridded emissions for ozone modeling, or to localized air quality dispersion modeling, where temporal and spatial resolution of emissions is essential to predict the concentration of pollutants near roadways
52

The operational and safety effects of heavy duty vehicles platooning

Alzahrani, Ahmed 01 January 2019 (has links)
Abstract Although researchers have studied the effects of platooning, most of the work done so far has focused on fuel consumption. There are a few studies that have targeted the impact of platooning on the highway operations and safety. This thesis focuses on the impact of heavy-duty vehicles (HDVs) platooning on highway characteristics. Specifically, this study aims at evaluating the effects of platooning of HDVs on capacity, safety, and CO2 emissions. This study is based on a hypothetical model that was created using the VISSIM software. VISSIM is a powerful simulation software designed to mimic the field traffic flow conditions. For model validity, the model outputs were compared with recommended values from guidelines such as the Highway Capacity Manual (HCM) (Transportation Research Board, 2016). VISSIM was used to obtain the simulation results regarding capacity. However, in addition to VISSIM, two other software packages were used to obtain outputs that cannot be assessed in VISSIM. MOVES and SSAM are two simulation software packages that were used for emission and safety metrics, respectively. Both software packages depended on input from VISSIM for analysis. It was found that with the presence of HDVs in the model, the capacity, the emission of CO2, and the safety of the roadway would improve positively. A capacity of 4200 PCE/h/ln could be achieved when there are enough HDVs in platoons. Furthermore, more than 3% of the traffic flow emission of CO2 reduction is possible when 100% of the HDVs used in the model are in platoons. In addition to that, a reduction of more than 75% of the total number of conflicts might be obtained. Furthermore, with the analysis of the full factorial method and the Design of Experiment (DOE) conducted by using Excel and Minitab respectively, it was possible to investigate the impact of the platoons’ factors on the highway parameters. Most of these factors affect the parameters significantly. However, the change in the desired speed was found to insignificantly affect the highway parameters, due to the high penetration rate. Keywords: VISSIM, MOVES, SSAM, COM-interface, HDVs, Platooning, Number of Conflicts
53

GPU component-based neighborhood search for Euclidean graph minimization problems / Méthodes GPU de recherche par voisinage pour les problèmes de minimisation de graphes Euclidiens

Qiao, Wenbao 22 September 2018 (has links)
Dans cette thèse, nous proposons des solutions parrallèles basées sur le systèmes actuel GPU (graphics processing unit) pour deux problèmes de minimisation de graphe Euclidien, à savoir le problème de forêt/arbre couvrant minimum Euclidien (EMSF / EMST) et le problème du voyageur commerce (TSP). Les solutions proposées résolvent également aussi le problème d'une paire bichromatique la plus proche (BCP), et suivent la technique de ``contrôle décentralisé, du parallélisme des données et des mémoires partagées par GPU".Nous proposons une technique de recherche dans le voisinage le plus proche de dimension K Euclidienne basée sur les approches classiques de NNS d’Elias qui divisent l’espace Euclidien en cellules congruentes et ne se chevauchant pas, où la taille des points de chaque cellule est délimitée. Nous proposons aussi une technique d'élagage pour obtenir le NNS à base de composants afin de trouver le point de sortie le plus proche de l'ensemble de points de requête de Q dans la complexité temporelle linéaire séquentielle lorsque les données sont uniformément réparties. Ces techniques sont utilisées conjointement avec deux GPU algorithmes proposés pour arbre traversement, à savoir la recherche en largeur bidirectionnelle GPU et la liste chaînée dynamique distribuée, afin d'adresser le BCP. Basé sur la solution BCP, un algorithme parallèle Divide and Conquer est implémenté pour construire EMSF et EMST totalement côté GPU. Le TSP est adressé avec différents algorithmes de recherche locaux parallèles 2-opt, dans lesquels nous proposons une méthodologie ``évaluation multiple K-opt, mouvements multiples K-opt" afin d’exécuter simultanément, sans interférence, des processus massifs 2-/3-opt mouvements qui se retrouvent globalement sur le même circuit TSP pour de nombreux bords. Cette méthodologie est expliquée en détail pour montrer comment nous obtenons un calcul haute performance à la fois du côté du GPU et CPU. Nous testons les solutions proposées et rapportons des résultats de comparaison expérimentale par rapport aux algorithmes de pointe. / In this thesis, we propose parallel solutions based on current graphics processing unit (GPU) system for two Euclidean graph minimization problems, namely the Euclidean minimum spanning forest/tree (EMSF/EMST) and the travelling salesman problem (TSP). The proposed solutions also solve the bichromatic closest pair (BCP) problem, and follow technique of ``decentralized control, data parallelism, GPU shared memories".We propose a Euclidean K-dimensional nearest neighbourhood search (NNS) technique based on classical Elias' NNS approaches that divide the Euclidean space into congruent and non-overlapping cells where size of points in each cell is bounded. We propose a pruning technique to obtain component-based NNS to find a query point set Q's closest outgoing point within sequential linear time complexity when the data is uniformly distributed. These techniques are used together with two proposed GPU tree traversal algorithms, namely the GPU two-direction Breadth-first search and distributed dynamic linked list, to address the BCP. Based on the BCP solution, a divide and conquer parallel algorithm is implemented for building EMSF and EMST totally on GPU side. The TSP is addressed with different parallel 2-opt local search algorithms, in which we propose a ``multiple K-opt evaluation, multiple K-opt moves" methodology in order to simultaneously execute, without interference, massive 2-/3-opt moves that are globally found on the same TSP tour for many edges. This methodology is explained in details to show how we obtain high performance computing both on GPU and CPU side. We test the proposed solutions and report experimental comparison results against the state-of-the-art algorithms.
54

利益議價行為與決策--以動態博奕分析全民健保法制定過程 / Bargaining behavior--A game-theoretic analysis in the National Health Care Law-making

王志宏, Wang, Vincent C.H. Unknown Date (has links)
本文主要運用博奕理論,分析全民健保法中各涉入者的議價行為,包括政黨及利益團體兩個層次之互動。主要探討下列問題:1、瞭解議價行為之動態賽局結構。2、參與者如何運用策略及其資源,以達到其偏好的理想點。3、如何透過議價來調節分歧的利益,規避社會衝突。4、如何透過理性的計算,如移動、反制、反反制的過程,達柏雷圖邊界。 第一章說明研究範圍與方法,及本文研究架構等。 第二章為理論基礎,先對傳統博奕理論提出修正,再介紹本文所採用之移動理論。 第三章說明本研究範圍內之行為者的立場、偏好等,並採二階賽局之觀點對兩層次之行為者的互動做一分析。 第四章把健保法立法過程依重要事件分為三段,分別運用賽局結 構分析其議價過程與結果。 第五章在針對第四章之均衡結果提出更進一步之分析,以康多賽贏家、中間選民定理、空間理論等來分析議題之社會選擇結果。 第六章提出研究限制和檢討,及本文結論。 / In the thesis , the author use game theory to analysis thebargaining behavior of the actors,including political parties and interest groups,in the Nationl Health Care Law-making. The purpose of this thesis contains four points.First of all,to figure out the structure of bargaining game.Second,how does the actors use their strategies and resourse to reach their ideal point.Third,how does the bargaining goes to come to an agreement, and avoid social conflict.forth and last,how can the rational actors use their strategies like move,counter-move,even counter counter-move to reach Pareto frontier.
55

Inventory Routing Investigations

Song, Jin-Hwa 08 July 2004 (has links)
The elimination of distribution inefficiencies, occurring due to the timing of customers' orders is an important reason for companies to introduce vendor managed inventory programs. By managing their customers' inventories, suppliers may be able to reduce demand variability and therefore distribution costs. We develop technology to measure the effectiveness of distribution strategies. We develop a methodology that allows the computation of tight lower bounds on the total mileage required to satisfy customer demand over a period of time. As a result, companies will be able to gain insight into the effectiveness of their distribution strategy. This technology can also be used to suggest desirable delivery patterns and to analyze tactical and strategic decisions. Secondly, we study the inventory routing problem with continuous moves (IRP-CM). The typical inventory routing problem deals with the repeated distribution of a single product, from a single facility, with an unlimited supply, to a set of customers that can all be reached with out-and-back trips. Unfortunately, this is not always the reality. We introduce the IRP-CM to study two important real-life complexities: limited product availabilities at facilities and customers that cannot be served using out-and-back tours. We need to design delivery tours spanning several days, covering huge geographic areas, and involving product pickups at different facilities. We develop a heuristic and an optimization algorithm to construct distribution plans. The heuristic is an innovative randomized greedy algorithm, which includes linear programming based postprocessing technology. To solve the IRP-CM to optimality, we give a time-discretized integer programming model and develop a branch-and-cut algorithm. As instances of time-discretized models tend to be large we discuss several possibilities for reducing the problem size. We introduce a set of valid inequalities, called delivery cover inequalities, in order to tighten the bounds given by the LP relaxation of the time-discretized model. We also introduce branching schemes exploiting the underlying structure of the IRP-CM. An extensive computational study demonstrates the effectiveness of the optimization algorithm. Finally, we present an integrated approach using heuristics and optimization algorithms providing effective and efficient technology for solving inventory problems with continuous moves.
56

Therapeutic Foster Parents' Perspectives of the Efficacy of Preservice Training

Grant, Mirae Jean 01 January 2015 (has links)
Preservice training programs offered in a city in the Pacific Northwest have not been assessed to determine whether they adequately prepare therapeutic foster parents (TFPs). This phenomenological study identified factors that influenced the impact of preservice training on parents' preparation to manage their foster children's behavior, foster parent attrition, and multiple moves of the foster children. Chamberlain, Rork, McNeil, and Christenson's work linking training programs with the success of foster children was used to frame this study. Data were generated from semistructured interviews of 12 certified local TFPs who had completed preservice training and had at least one child placed in their home for at least a weekend. NVivo 10 qualitative analysis software was used to manage the data, which were analyzed via an inductive process. Findings indicated that TFPs felt the training was effective and the information provided was useful in real life situations. Suggestions for improvement included adding additional examples of behavioral issues and personal stories from trainers and facilitating increased interaction among foster parents. TFPs reported that their intrinsic motivations for fostering had more impact on decisions to continue with foster children in their home than did the preservice training. The project generated from the study was a policy recommendation addressed to program stakeholders that could have a significant social impact in developing training to better address behavioral challenges, prevent multiple moves, and promote cultural sensitivity while reinforcing parents' motivation for fostering.
57

Разработка принципов построения схем зубофрезерного станка с безгитарным приводом : магистерская диссертация / Working out principles of hobbing machines schemes design with gear free drive

Белянцева, И. В., Belyantseva, I. V. January 2017 (has links)
Relevance of this research is conditioned by necessity of increasingmetalworking machines efficiency in modern machinery building. One of the main constructive elements of gear milling machines is mechanical gear train (speed gear train, feed gear train, dividing gear train, differential gear train). The adjustment of all these shaping moves is important objective. Though mechanical gear trains do not provide high tooling precision.That’s why precision can be increased by developing ways of replacing mechanical gear trains by hydraulic and electronic analogs. These ways were poorly considered before. Goal of the work: analyzing of existing principal gear milling machine schemes, analyzing of possible ways of shaping moves electronic adjustment, descrying of various frequent divisor structures. Calculation unevennessof impulses following for divisors, that work in different codes and improving schemes of machines with electric step motor and adjustable electric motor by way of increasing tooling precision. Master’s dissertation consists of 6 chapters: Chapter 1: Modern gear milling machines principal schemes. This chapter describes function of gear trains, structure of cutting moves in gear milling and schemes of existing gear milling machines with mechanical and electronic gear trains. Chapter 2: Analysis of ways and tools of electronic (“Non-gear-train”) adjustment of machine’s shaping moves. This chapter describes ways of coordinating an adjustable electronic motor and electronic step motor, ways of coordinating two adjustable electronic motors. Chapter 3: modern constructions of impulse frequency divisors. Schemes andfunctioning of divisors. This chapter analyze various schemes of frequency divisors, ways of divisor selecting for gear milling machine, calculating the unevenness of impulses, transferring with divisors for various codes. Chapter 4: Improvement of gear milling machines with electric step motor Suggestion of improved kinematic schemes for electric step motor milling machines. Chapter 5: Improvement in schemes of gear milling machines with adjustable electric motor. Suggestion of improved kinematic schemes for adjustable electric motor milling machines. Chapter 6: Work out of technical proposal for gear milling machine with adjustable electric motor. Chapter contains selection of electric motor for chosen kinematic scheme with electronic gear train, kinematic and robustness calculation, comparison of mechanical and electronic gears’ precision. Master’s dissertation consist of 128 pages, containing demonstrational materials, calculations and text description, and 17 graphic documents. / Актуальность темы исследования обусловлена необходимостью повышения эффективности металлорежущих станков в современном машиностроении. Одними из основных конструктивных элементов зубофрезерного станка являются механические гитары (скоростей, подач, деления, дифференциала). Важной задачей является согласовать всеэти формообразующие движения. Но механические гитары не обеспечивают высокой точности обработки. Поэтому были разработаны способы повышения точности путем замены механических гитар гидравлическими и электронными. Ранее эти способы были рассмотрены поверхностно. Цель работы: проведение анализа существующих принципиальных схем зубофрезерных станков, анализ возможных способов электронного согласования формообразующих движений, рассмотрение различных конструкций делителей частоты, расчет неравномерности следования импульсов для делителей, работающих в различных кодах, и совершенствование схем станков с шаговым и регулируемым электроприводами для повышения точности обработки. Магистерская диссертация состоит из 6 глав: Глава 1: Принципиальные схемы современных зубофрезерных станков В главе рассматривается назначение гитар, структура рабочего движения при зубофрезеровании, а также существующие кинематические схемы зубофрезерных станков с механическими и электронными гитарами. Глава 2: Анализ способов и средств электронного («безгитарного») согласования формообразующих движений в станке В главе описываются способы согласования работы регулируемого и шагового приводов, и согласование работы двух регулируемых приводов. Глава 3: Современные конструкции делителей частоты импульсов, их устройство и работа В главе анализируются различные конструкции делителей частоты, также производится выбор делителя, применительно к зубофрезерному станку. Производится расчет неравномерности следования импульсов, передаваемых через делители для различных кодов. Глава 4: Совершенствование зубофрезерных станков с шаговым электроприводом Предлагаются усовершенствованные кинематические схемы станков с шаговыми электроприводами. Глава 5: Совершенствование схем зубофрезерных станков с регулируемыми электроприводами Предлагаются усовершенствованные кинематические схемы станков с регулируемыми электроприводами. Глава 6: Разработка технического предложения зубофрезерного станка с регулируемыми электроприводами В главе выбирается электродвигатель для выбранной кинематической схемы с электронной гитарой, производится кинематический и прочностной расчет и сравниваются по точности механическая и электронная гитары. Магистерская диссертация выполнена на 128 страницах, содержащих демонстрационные материалы, расчеты и описание, и включает 17 графических документов.
58

Domov jako téma českých filosofických prací 20. a 21. století / Home as the topic of Czech philosophical work 20th and 21st century.

PŘEVRÁTILOVÁ, Pavlína January 2018 (has links)
The diplom a thesis deals with home and its concepts in philosophical works. The aim was to grasp and describe home as a philosophical category, using the ideas and theories that we found in the Czech philosophical texts that came out during the 20th and 21st centuries. Through these available information, we have attempted to unify and create a more coherent, interconnected theory, in which we divided home intoseveral basic chapters that are absolutely decisive and decisive for the concept and understanding of home, both past and present.

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