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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.
61

Le miel en Égypte Ancienne : histoire et fonctions d'un produit précieux / The Honey in Ancient Egypt : history and Functions of a valuable Product.

Lafont, Julie 08 December 2018 (has links)
Cette thèse de Doctorat, intitulée « Le miel en Égypte ancienne. Économie et fonction d’un produit précieux », a pour principal objectif d’identifier les différents domaines dans lesquels le miel intervenait dans la société égyptienne antique. Elle évalue notamment l’état des connaissances des Anciens Égyptiens en matière d’apiculture : les techniques employées depuis la récolte jusqu’à la mise en pot, le choix des zones géographiques de production, la typologie des miels.Elle vise également à révéler l’existence d’une économie spécifique à cette denrée enconsidérant notamment sa distribution, sa valeur marchande au cours de l’histoirepharaonique ainsi que la portée des échanges avec les cultures voisines.Enfin, elle interroge les textes afin de définir les divers usages du miel : alimentaire, au moyen des scènes de « pâtisserie » et des nombreuses listes d’offrandes ; médical, grâce aux papyri médico-magiques ; rituel, à travers l’étude des inscriptions de tombes et de temples. / Entitled "Honey in Ancient Egypt. Economy and Functions according to a valuable product", this PhD thesis main objective is to identify the various areas where the honey had a role in ancient Egyptian society. This study assesses specifically the state of knowledge of the ancient Egyptians in terms of beekeeping techniques from harvest to potting, as well as the selection of adapted geographical areas of production and the existing classification of each type of honey.My PhD thesis aims at showing the existence of a specific economy for this commodity and especially its distribution, its market value during the Pharaonic history and the scope of exchanges with neighbouring cultures.Finally, this research examines texts to define the various daily uses of honey : food, consisting in scenes of "pastry", many lists of offerings, etc. ; medical, thanks to medical-magical papyri ; ritual, through the study of inscriptions of tombs and temples.
62

Utilização da simulação a eventos discretos para o gerenciamento do almoxarifado de materiais utilizados numa indústria automotiva /

Santana, Wagner Augusto Lemos de. January 2018 (has links)
Orientador: Fernando Augusto Silva Marins / Coorientador: Aneirson Francisco da Silva / Banca: Dimas Campos de Aguiar / Banca: Rosinei Batista Ribeiro / Resumo: Os processos de recebimento, conferência, armazenagem, separação de pedidos, montagem de kits, distribuição de materiais e inventário são processos vitais dentro dos almoxarifados e interferem diretamente na efetividade da Cadeia de Suprimentos (Supply Chain - SC). Como esses processos sofrem várias interferências, devido a outros processos da SC, como compra de materiais, planejamento, programação e abastecimento da produção, tornam-se comuns situações como excessos de materiais, baixa acuracidade dos estoques, dificuldade de localização, falhas no atendimento dos pedidos e montagem de kits, entre outros. Pensando nestas dificuldades gerenciais, busca-se, nesta dissertação, utilizar uma pesquisa de natureza aplicada, com objetivos empíricos e descritivos e análise quantitativa para desenvolver uma ferramenta gerencial, com base em um modelo de simulação a eventos discretos, como apoio às decisões sobre os recursos necessários para execução de forma efetiva dos processos citados. O objeto de estudo foi um almoxarifado de produtos estampados de uma empresa multinacional no setor automotivo. Onde a criação de um modelo conceitual e aplicação da simulação foram os objetivos. Adotou-se a técnica IDEF-SIM para a modelagem conceitual do problema e foi utilizado o software ProModel® para se obter uma racionalização na aplicação dos recursos necessários para que o almoxarifado tenha um melhor desempenho, frente a vários cenários possíveis de ocorrer. Identificou-se, após a simulação,... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The processes of receiving, conferring, storing, sorting orders, assembling kits, distributing materials and inventory are vital processes within warehouses and directly interfere with the effectiveness of the Supply Chain (SC). As these processes suffer several interferences, due to other SC processes, such as material purchase, planning, scheduling and production supply, situations such as material excesses, low inventory accuracy, difficulty in locating, ordering and assembling kits, among others. In this dissertation, we intend to use a research of an applied nature, with empirical and descriptive objectives and quantitative analysis to develop a managerial tool, based on a simulation model to discrete events, as support to the decisions about the necessary resources to effectively execute the cited cases. The object of study was a warehouse of stamped products of a multinational company in the automotive sector. Where the creation of a conceptual model and application of the simulation were the objectives. The IDEF-SIM technique was adopted for the conceptual modeling of the problem and ProModel® software was used to obtain a rationalization in the application of the necessary resources so that the warehouse performs better, against several possible scenarios to occur. It was found after the simulation that one of the main problems in the operation of the warehouse was related to the unbalanced arrival of the items that form the kits, another one related to the excessive... (Complete abstract click electronic access below) / Mestre
63

Včelaření v České republice na rozcestí / The Beekeepering in The Czech Republic on crossroads

Mohrová, Kateřina January 2016 (has links)
The thesis entitled The Beekeeping in the Czech Republic on Crossroads aims to get in the current issues of beekeeping. It describes the field of beekeeping, one of the oldest human activities in terms of biology, ecology, history, sociology and practical use. The methodology of this thesis is set in the framework of qualitative research and the discipline of social and cultural ecology which is based on multidisciplinary research. During the research a questionnaire construction was used. The research part focuses on the social and generational issues of beekeeping and reveals the motivation of my respondents for keeping bees. Furthermore it interprets the opinion of my respondents on beekeeping organizations in the Czech Republic, their connection with nature and their own outlook for the near future of beekeeping. In the discussion I summarize the results of the interviews with my respondents and in the conclusion I re-evaluate the aimed goals of my thesis and I give suggestions for further research possibilities in this field.
64

Hybrid Station-Keeping Controller Design Leveraging Floquet Mode and Reinforcement Learning Approaches

Andrew Blaine Molnar (9746054) 15 December 2020 (has links)
The general station-keeping problem is a focal topic when considering any spacecraft mission application. Recent missions are increasingly requiring complex trajectories to satisfy mission requirements, necessitating the need for accurate station-keeping controllers. An ideal controller reliably corrects for spacecraft state error, minimizes the required propellant, and is computationally efficient. To that end, this investigation assesses the effectiveness of several controller formulations in the circular restricted three-body model. Particularly, a spacecraft is positioned in a L<sub>1</sub> southern halo orbit within the Sun-Earth Moon Barycenter system. To prevent the spacecraft from departing the vicinity of this reference halo orbit, the Floquet mode station-keeping approach is introduced and evaluated. While this control strategy generally succeeds in the station-keeping objective, a breakdown in performance is observed proportional to increases in state error. Therefore, a new hybrid controller is developed which leverages Floquet mode and reinforcement learning. The hybrid controller is observed to efficiently determine corrective maneuvers that consistently recover the reference orbit for all evaluated scenarios. A comparative analysis of the performance metrics of both control strategies is conducted, highlighting differences in the rates of success and the expected propellant costs. The performance comparison demonstrates a relative improvement in the ability of the hybrid controller to meet the mission objectives, and suggests the applicability of reinforcement learning to the station-keeping problem.
65

Evaluating Vehicle Data Analytics for Assessing Road Infrastructure Functionality

Justin Anthony Mahlberg (9746357) 15 December 2020 (has links)
The Indiana Department of Transportation (INDOT) manages and maintains over 3,000 miles of interstates across the state. Assessing lane marking quality is an important part of agency asset tracking and typically occurs annually. The current process requires agency staff to travel the road and collect representative measurements. This is quite challenging for high volume multi-lane facilities. Furthermore, it does not scale well to the additional 5,200 centerline miles of non-interstate routes. <div><br></div><div>Modern vehicles now have technology on them called “Lane Keep Assist” or LKA, that monitor lane markings and notify the driver if they are deviating from the lane. This thesis evaluates the feasibility of monitoring when the LKA systems can and cannot detect lane markings as an alternative to traditional pavement marking asset management techniques. This information could also provide guidance on what corridors are prepared for level 3 autonomous vehicle travel and which locations need additional attention. </div><div><br></div><div>In this study, a 2019 Subaru Legacy with LKA technology was utilized to detect pavement markings in both directions along Interstates I-64, I-65, I-69, I-70, I-74, I90, I-94 and I-465 in Indiana during the summer of 2020. The data was collected in the right most lane for all interstates except for work zones that required temporary lane changes. The data was collected utilizing two go-pro cameras, one facing the dashboard collecting LKA information and one facing the roadway collecting photos of the user’s experience. Images were taken at 0.5 second frequency and were GPS tagged. Data collection occurred on over 2,500 miles and approximately 280,000 images were analyzed. The data provided outputs of: No Data, Excluded, Both Lanes Not Detected, Right Lane Not Detected, Left Lane Not Detected, and Both Lanes Detected. </div><div><br></div><div>The data was processed and analyzed to create spatial plots signifying locations where markings were detectable and locations where markings were undetected. Overall, across 2,500 miles of travel (right lane only), 77.6% of the pavement markings were classified as both detected. The study found</div><div><br></div><div>• 2.6% the lane miles were not detected on both the left and right side </div><div>• 5.2% the lane miles were not detected on the left side </div><div>• 2.0% the lane miles were not detected on the right side 8 </div><div><br></div><div>Lane changes, inclement weather, and congestion caused 12.5% of the right travel lane miles to be excluded. The methodology utilized in this study provides an opportunity to complement the current methods of evaluating pavement marking quality by transportation agencies. </div><div><br></div><div>The thesis concludes by recommending large scale harvesting of LKA from a variety of vendors so that complete lane coverage during all weather and light conditions can be collected so agencies have an accurate assessment of how their pavement markings perform with modern LKA technology. Not only will this assist in identifying areas in need of pavement marking maintenance, but it will also provide a framework for agencies and vehicle OEM’s to initiate dialog on best practices for marking lines and exchanging information.</div>
66

Keeping record : applying organisational communication in intermediate phase classrooms

Ramcharan, Aneel January 2002 (has links)
A thesis submitted in fulfilment of the Requirements for the degree of MA in Communication Science University of Zululand, 2002 / In this thesis I present my recommendations regarding the role of organisational com¬munication and record keeping in Outcomes-Based Education within the intermediate phase classroom. I reveal that the fundamental switch from the traditional educator-centred teaching to learner-centred teaching in Out-comes Based Education requires that both educators and learners be in command of a range of communication strategies in order to construct meaning in the real-world social contexts. It will also be illustrated that intra-personal, interpersonal and small group involvements are all essential for successful teaching and learning to take place. The importance of verbal as well as nonverbal communication skills are also given due attention. Outcomes-Based Education is based not on knowledge, but on how we think learning takes place. The focus is on the mind of the learner as an knaginer, an inventor, a creator of ideas. What is clearly evident with this approach is the manner in which learners constandv ne¬gotiate, renegotiate and construct their own meaning. The focus is on the individual and not on the group. With this in mind, we need to note that everyone learns differently and we need to assess accordingly. As educators we also need to recognise what learners have learnt and we need to find ways of acknowledging that learning has indeed taken place. Out-comes Based Education requires a cooperative method of teaching which allows for democracy in the classroom. Learners are allowed to contribute freely about their daily ex¬periences. Further to this I examine the forms of communication that learners and educators must be in command of to succeed in OBE. I further recommend tools that can be imple¬mented to successfully manage assessments in OBE classrooms. A flexible database of spread¬sheets will be presented which could be adapted to suit individual schools.
67

Homiletical Squib: “A time to keep silence, and a time to speak” (Eccl 3:7b) Preaching and keeping silent in times of the COVID19-pandemic

Deeg, Alexander 01 October 2020 (has links)
“A time to keep silence, and a time to speak” (Eccl 3:7b) Preaching and keeping silent in times of the COVID19-pandemic
68

Stratégies de maintien à poste pour un satellite géostationnaire à propulsion tout électrique / Station keeping strategies for geostationary satellites equipped with electric propulsion

Gazzino, Clément 25 January 2018 (has links)
Pour mener à bien leur mission, les satellites de télécommunications doivent rester à la verticale d'un même point de la Terre, sur une orbite dite géostationnaire, pour laquelle la période de révolution des satellites sur leur orbite est identique à la période de rotation de la Terre sur elle-même. Cependant, à cause des perturbations orbitales, les satellites tendent à s'en éloigner, et il est alors nécessaire de concevoir des stratégies de commande pour les maintenir dans un voisinage de cette position de référence. Du fait de leur grande valeur de poussée, les systèmes à propulsion chimique ont largement été utilisés, mais aujourd'hui les systèmes à propulsion électrique avec leur grande impulsion spécifique sont des alternatives viables pour réduire la masse d'ergols du satellite, et ainsi le coût au lancement, ou allonger la durée de vie du satellite, ce qui permettrait de limiter l'encombrement dans l'espace. Cependant, l'utilisation d'un tel système propulsif induit des contraintes opérationnelles issues en partie du caractère limité de la puissance électrique disponible à bord. Ces contraintes sont difficiles à prendre en compte dans la transcription du problème de maintien à poste en un problème de contrôle optimal à consommation minimale avec contraintes sur l'état et le contrôle. Ce manuscrit propose deux approches pour résoudre ce problème de commande optimale. La première, basée sur le développement et l'exploitation de conditions nécessaires d'optimalité, consiste à découper le problème initial en trois sous-problèmes pour former une méthode de résolution à trois étapes. La première étape permet de résoudre un problème de maintien à poste expurgé des contraintes opérationnelles, tandis que la deuxième, initialisée par le résultat de la première, produit une solution assurant le respect de ces dernières contraintes. La troisième étape permet d'optimiser la valeur des instants d'allumage et d'extinction des propulseurs dans le cadre du formalisme des systèmes à commutation. La seconde approche, dite " directe ", consiste à paramétrer le profil de commande par une fonction binaire et à le discrétiser sur l'horizon temporel de résolution. Les contraintes opérationnelles sont ainsi facilement transcrites en contraintes linéaires en nombres entiers. Après l'intégration numérique de la dynamique, le problème de contrôle optimal se résume à un problème linéaire en nombres entiers. Après la résolution du problème de maintien à poste sur un horizon court d'une semaine, le problème est résolu sur un horizon long d'un an par résolutions successives sur des horizons courts d'une durée de l'ordre de la semaine. Des contraintes de fin d'horizon court doivent alors être ajoutées afin d'assurer la faisabilité de l'enchaînement des problèmes sur l'horizon court constituant le problème sur l'horizon long. / Geostationary spacecraft have to stay above a fixed point of the Earth, on a so-called geostationary Earth orbit. For this orbit, the orbital period of the spacecraft is equal to the rotation period of the Earth. Because of orbital disturbances, spacecraft drift away their station keeping position. It is therefore mandatory to create control strategies in order to make the spacecraft stay in the vicinity of the station keeping position. Due to their high thrust capabilities, chemical thrusters have been widely used. However nowadays electric propulsion based thrusters with their high specific impulse are viable alternative in order to decrease the spacecraft mass or increase its longevity. The use of such a system induce the necessity to handle operational constraints because of the limited on-board power. These operational constraints are difficult to take into account in the mathematical transcription of the station keeping problem in an optimal control problem with control and state constraints. This thesis proposed two techniques in order to solve this optimal control problem. The first one is based on the computation of first order necessary conditions and consists in decomposing the overall problem in three sub-problems, leading to a three-step decomposition method. The first step solves an optimal control problem without the operational constraints. The second steps enforces these operational constraints thanks to dedicated equivalence schemes and the third one optimises the switching times of the control profile thanks to a method borrowed from the switched systems theory. The second proposed method consists in parametrising the on-off control profile with binary functions. After a time discretisation of the station keeping horizons, the operational constraints are easily recast as linear constraints on integer variables, the dynamics is numerically integrated and the station keeping problem is recast as a mixed integer linear programming problem. After the resolution of the problem over a short time horizon of one week, the station keeping problem is solved over a long time horizon of one year. To this end, the long time horizon is split in shorter horizons over which the problem is successively solved. End-of-cycle constraints have been set up in order to ensure the feasibility of the solution one short horizon after another.
69

Modeling and Simulation of Lane Keeping Support System Using Hybrid Petri Nets

Padilla, Carmela Angeline C. 08 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / In the past decades, the rapid innovation of technology has greatly affected the automotive industry. However, every innovation has always been paired with safety risks that needs to be quickly addressed. This is where Petri nets (PNs) have come into the picture and have been used to model complex systems for different purposes, such as production management, traffic flow estimation and the introduction of new car features collectively known as, Adaptive Driver Assistance Systems (ADAS). Since most of these systems include both discrete and continuous dynamics, the Hybrid Petri net (HPN) model is an essential tool to model these. The objective of this thesis is to develop, analyze and simulate a lane keeping support system using an HPN model. Chapter 1 includes a brief summary of the specific ADAS used, lane departure warning and lane keeping assist systems and then related work on PNs is mentioned. Chapter 2 provides a background on Petri nets. In chapter 3, we develop a discrete PN model first, then we integrate continuous dynamics to extend it to a HPN model that combines the functionalities of the two independent ADAS systems. Several scenarios are introduced to explain the expected model behavior. Chapter 4 presents the analysis and simulation results obtained on the final model. Chapter 5 provides a summary for the work done and discusses future work.
70

COMPUTER VISION BASED ROBUST LANE DETECTION VIA MULTIPLE MODEL ADAPTIVE ESTIMATION TECHNIQUE

Iman Fakhari (11806169) 07 January 2022 (has links)
The lane-keeping system in autonomous vehicles (AV) or even as a part of the advanced driving assistant system (ADAS) is known as one of the primary options of AVs and ADAS. The developed lane-keeping systems work on either computer vision or deep learning algorithms for their lane detection section. However, even the strongest image processing units or the robust deep learning algorithms for lane detection have inaccuracies during lane detection under certain conditions. The source of these inaccuracies could be rainy or foggy weather, high contrast shades of buildings and objects on-street, or faded lines. Since the lane detection unit of these systems is responsible for controlling the steering, even a momentary loss of lane detection accuracy could result in an accident or failure. As mentioned, different lane detection algorithms have been presented based on computer vision and deep learning during the last few years, and each one has pros and cons. Each model may have a better performance in some situations and fail in others. For example, deep learning-based methods are vulnerable to new samples. In this research, multiple models of lane detection are evaluated and used together to implement a robust lane detection algorithm. The purpose of this research is to develop an estimator-based Multiple Model Adaptive Estimation (MMAE) algorithm on the lane-keeping system to improve the robustness of the lane detection system. To verify the performance of the implemented algorithm, the AirSim simulation environment was used. The test simulation vehicle was equipped with one front camera and one back camera used to implement the proposed algorithm. The front camera images are used for detecting the lane and the offset of the vehicle and center point of the lane. The rear camera, which offered better performance in lane detection, was used as an estimator for calculating the uncertainty of each model. The simulation results showed that combining two implemented models with MMAE performed robustly even in those case studies where one of the models failed. The proposed algorithm was able to detect the failures of either of the models and then switch to another good working model to improve the robustness of the lane detection system. However, the proposed algorithm had some limitations; it can be improved by replacing PID controller with an MPC controller in future studies. In addition, in the presented algorithm, two computer vision-based algorithms were used; however, adding a deep learning-based model could improve the performance of the proposed MMAE. To have a robust deep learning-based model, it is suggested to train the network based on AirSim output images. Otherwise, the network will not work accurately due to the differences in the camera's location, camera configuration, colors, and contrast.

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