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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.
11

Réaction d'échange alcool / ester : alcoolyse : application aux polymères / Exchange reaction alcohol / ester : alcoholysis : applications to polymers

Touhtouh, Samira 21 April 2011 (has links)
Cette étude porte sur l’élaboration de polymères greffés à base de poly(éthylène alcool vinylique) (EVOH) et de la polycaprolactone (PCL). La réaction de greffage a lieu par la réaction d’alcoolyse entre les groupements ester de la polycaprolactone et les groupements alcools le long des chaînes d’EVOH. L’étude catalytique et cinétique par des études GC/MS très détaillées, facilitées par l’utilisation de réactions modèles avec le 1-dodécyl benzoate et le 2-dodécanol, montre la possibilité de la synthèse par extrusion réactive. L’activité catalytique de 1.5.7-triazabicyclo[4.4.0]dec-5-ene pour la réaction d’alcoolyse sans solvant et pas extrusion réactive a été confirmé. Les conditions de l’extrusion permettant un taux de greffage optimal ont été déterminées et l’effet déterminant de la température a été confirmé. Le taux de greffage peut être obtenu par des analyses 1H-RMN. Ces résultats combinés à la microscopie électronique à balayage et en transmission ont permis de déterminer les caractéristiques optimales des polymères employés afin de former des mélanges nanostructurés. Les mêmes conditions de synthèse appliqués à d’autres matériaux comme le polyméthacrylate de méthyle, acide polylactique et poly(3-hydroxybutyrate-co-3-hydroxyvalérate) ont permis l’élaboration des copolymères greffés pour des applications biomédicales / This study focuses on the development of graft polymers based on poly (ethylene vinyl alcohol) (EVOH) and polycaprolactone (PCL). The grafting reaction takes place by the alcoholysis reaction between ester groups of the polycaprolactone and alcohol groups along the chains of EVOH. The catalytic and kinetic studies by GC / MS highly detailed, facilitated by the use of model reactions with 1-dodecyl benzoate and 2-dodecanol, shows the possibility of synthesis by reactive extrusion. The catalytic activity of triazabicyclo-1.5.7 [4.4.0] dec-5-ene for the alcoholysis reaction without solvent and by reactive extrusion has been confirmed. The extrusion conditions for optimum rate of grafting were determined and the effect of temperature has been confirmed. The rate of grafting can be obtained by 1H-NMR analysis. These results combined with scanning electron microscopy and transmission, have determined the optimum characteristics of polymers to form nanostructured blends. The same synthesis conditions applied to other materials such as polymethylmethacrylate, polylactic acid and poly (3-hydroxybutyrate-co-3-hydroxyvalerate) allowed the preparation of graft copolymers for biomedical applications
12

Ein Beitrag zur Optimierung der Betriebsweise heizungs- und raumlufttechnischer Anlagen

Felsmann, Clemens 10 August 2002 (has links) (PDF)
Im Rahmen der vorliegenden Arbeit wird gezeigt, wie ein Gebäude- und Anlagensimulationsprogramm mit bekannten Optimierungsalgorithmen gekoppelt und zur theoretischen Lösung optimaler Steuer- und Regelprobleme in der Gebäudetechnik eingesetzt werden kann. Theoretische Optimallösungen erlauben im Sinne eines optimalen Vergleichsprozesses die Bewertung praktisch anderweitig umsetzbarer Steuerungs- und Regelungsmechanismen. Die im Hinblick auf ein gewähltes Gütekriterium erforderliche Notwendigkeit zur Verbesserung von vorhandenen Steuerungs- und Regelungsszenarien sowie die theoretisch maximal erreichbaren Extremwerte lassen sich leicht abschätzen.
13

MIGRATION FROM VAX TO MODERN ALPHA COMPUTERS

Nötzel, Klaus R. 10 1900 (has links)
International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / Deutsche Telekom has been operating different communication satellites for several years. The Satellite Control Center (SCC) of Deutsche Telekom is located near Usingen, about 50 km northwest of Frankfurt/Main. The system has been under operation since the launch of the first flight model DFS in June 1989. The entire computer system was based on Digital Equipment Corporation (DEC) VAX type computers. The maintenance costs of these old Complex Instruction Sets Computers (CISC) were increased significantly during the last years. Due to the high operational costs Deutsche Telekom decided to exchange the operational computer system. Present-day information technology world uses more and more powerful Reduced Instruction Set Computers (RISC). These new designs allow operational costs to be reduced appreciably. The VAX type computers will be replaced by DEC Alpha AXP Computers. This paper describes the transition process from CISC to RISC computers in an operational realtime environment.
14

Let’s get the Conversation Started on the new DEC Recommended Practices

Trivette, Carol M. 01 January 2014 (has links)
No description available.
15

DEC Recommended Practices: Building the Capacity of Families

Trivette, Carol M. 01 January 2014 (has links)
No description available.
16

The DEC Recommended Practices and Young Abused Children with Disabilities

Corr, Catherine, Trivette, Carol M., Santo, Rosa Milagros, Connor, Susan 01 February 2016 (has links)
No description available.
17

TaxiWorld: Developing and Evaluating Solution Methods for Multi-Agent Planning Domains

January 2011 (has links)
abstract: TaxiWorld is a Matlab simulation of a city with a fleet of taxis which operate within it, with the goal of transporting passengers to their destinations. The size of the city, as well as the number of available taxis and the frequency and general locations of fare appearances can all be set on a scenario-by-scenario basis. The taxis must attempt to service the fares as quickly as possible, by picking each one up and carrying it to its drop-off location. The TaxiWorld scenario is formally modeled using both Decentralized Partially-Observable Markov Decision Processes (Dec-POMDPs) and Multi-agent Markov Decision Processes (MMDPs). The purpose of developing formal models is to learn how to build and use formal Markov models, such as can be given to planners to solve for optimal policies in problem domains. However, finding optimal solutions for Dec-POMDPs is NEXP-Complete, so an empirical algorithm was also developed as an improvement to the method already in use on the simulator, and the methods were compared in identical scenarios to determine which is more effective. The empirical method is of course not optimal - rather, it attempts to simply account for some of the most important factors to achieve an acceptable level of effectiveness while still retaining a reasonable level of computational complexity for online solving. / Dissertation/Thesis / M.S. Computer Science 2011
18

Defeitos de esmalte em dentes dec?duos: preval?ncia e fatores associados. / Enamel defects in the primary teeth: prevalence and associated factors

Faria, Patr?cia Corr?a de January 2011 (has links)
Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-01-23T16:14:44Z No. of bitstreams: 5 patricia.pdf: 1377961 bytes, checksum: 55ce7c1439d8b1123461e7f1f40d7a17 (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-02-10T10:38:49Z (GMT) No. of bitstreams: 5 patricia.pdf: 1377961 bytes, checksum: 55ce7c1439d8b1123461e7f1f40d7a17 (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) / Made available in DSpace on 2015-02-10T10:38:49Z (GMT). No. of bitstreams: 5 patricia.pdf: 1377961 bytes, checksum: 55ce7c1439d8b1123461e7f1f40d7a17 (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2109 bytes, checksum: aa477231e840f304454a16eb85a9235f (MD5) Previous issue date: 2013 / Os estudos sobre o desenvolvimento de defeitos de esmalte e a associa??o com as condi??es natais e p?s-natais ainda s?o escassos. Assim, este estudo teve como objetivo avaliar a preval?ncia de defeitos de esmalte em dentes dec?duos e verificar se prematuridade, peso ao nascimento e vari?veis sociodemogr?ficas podem estar associados a tais defeitos. Foi realizado um estudo transversal com 381 crian?as com idade entre 3 e 5 anos. Os dados foram coletados atrav?s de exame cl?nico e entrevistas com os pais durante Campanha Nacional de Vacina??o. O diagn?stico dos defeitos de esmalte foi realizado utilizando-se o Developmental Defects of Enamel Index (DDE Index). Atrav?s de entrevista foram coletadas informa??es sobre aspectos sociodemogr?ficos, gesta??o, peso ao nascimento, prematuridade da crian?a e amamenta??o. A an?lise dos dados foi realizada utilizando-se o programa SPSS for Windows 17.0 e incluiu a distribui??o de frequ?ncia, testes qui-quadrado e Exato de Fisher e regress?o de Poisson. A preval?ncia de defeito de esmalte foi de 29,9% e a opacidade demarcada foi o tipo de defeito mais frequente. Crian?as com peso muito baixo ao nascimento apresentam mais chance de desenvolver defeitos de esmalte [RP (IC95%) = 2,7 (1,66-4,61)]. A prematuridade e as vari?veis sociodemogr?ficas n?o foram fatores associados aos defeitos de esmalte. Crian?as com peso muito baixo ao nascimento apresentaram maior preval?ncia de defeitos de esmalte nos dentes dec?duos. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Odontologia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2011. / ABSTRACT Studies regarding the development of enamel defects and association with natal and postnatal conditions are scarce. Thus, the aim of this study was to evaluate the prevalence of enamel defects in primary teeth and determine whether prematurity, birth weight and sociodemographic variables may be associated with such defects. This was a cross-sectional study with 381 children aged between 3 and 5 years. Data were collected through clinical examination and interviews with parents during the National Immunization Day. The diagnosis of enamel defects was performed using the Development Defects of Enamel Index (DDE Index). During interviews, information were collected on sociodemographic aspects, pregnancy, birth weight, child prematurity and breastfeeding. Statistical analysis was performed using the SPSS software for Windows 17.0 and involved descriptive analysis, the Fisher?s test, qui-square test and Poisson regression. The prevalence of enamel defects was 29.9% and demarcated opacity was the most frequent type of defect. Children with low birth weight presented greater prevalence of enamel defects [PR (CI 95%) = 2,7 (1.66-4.61)]. Prematurity and the sociodemographic variables were not factors associated with enamel defects. In this study, children with very low birth weight had higher prevalence of enamel defects in deciduous teeth.
19

Valida??o de um m?todo auxiliar de diagn?stico como preditivo da presen?a de c?rie de dentina em dentes dec?duos

Carvalho, Guilherme Moura de 19 May 2006 (has links)
Made available in DSpace on 2014-12-17T15:31:00Z (GMT). No. of bitstreams: 1 GuilhermeMC.pdf: 675094 bytes, checksum: 480716331db06f40e13bac10b74ea070 (MD5) Previous issue date: 2006-05-19 / Esse estudo se prop?s a avaliar um m?todo auxiliar de diagn?stico (DIAGNOdent?) na predi??o de c?rie de dentina em dentes dec?duos, atrav?s de valida??o histol?gica e de microdureza. Verificando poss?veis diferen?as entre os valores obtidos atrav?s do m?todo auxiliar, al?m de determinar um ponto de corte para parada de remo??o de tecido cariado. A amostra do estudo foi de 15 crian?as que apresentaram 21 cavidades de c?rie, tratadas e analisadas desde antes da realiza??o da restaura??o at? quando da exodontia do elemento dent?rio. Os esp?cimes foram analisados atrav?s do DIAGNOdent? antes da abertura das cavidades, ap?s a remo??o do tecido cariado e depois da reabertura das cavidades que se deu ap?s a exodontia dos elementos dent?rios. Posteriormente, receberam preparo metalogr?fico para realiza??o de testes de microdureza e microscopia ?ptica que serviram como forma de valida??o para as mensura??es obtidas pela fluoresc?ncia a laser. Houve diferen?a significativa entre os valores DIAGNOdent? encontrados antes da abertura da cavidade e os demais (p < 0,0001). Havendo correla??o significativa (r = 0,432 ; p = 0,019) apenas para as aferi??es obtidas antes da abertura das cavidades e quando do t?rmino da remo??o do tecido cariado. Para a microdureza, as m?dias axiais foram significativamente maiores que as pulpares, existindo correla??o entre a microdureza pulpar e os valores do DIAGNOdent? ap?s a reabertura (r = - 0,472 ; p = 0,002). Valores de 15,38% para a sensibilidade, 100% para a especificidade, 100% para o valor preditivo positivo e 71,79% para o valor preditivo negativo, foram obtidos quando se utilizou um ponto de corte de 30 para fluoresc?ncia a laser, tendo como padr?o-ouro a microdureza pulpar. Partindo da m?dia dos valores de fluoresc?ncia a laser obtidos ap?s a remo??o do tecido cariado e acrescentando-se um desvio-padr?o a esta, o m?todo indicou o valor de 19 como ponto de corte para cessar a remo??o de dentina. Concluiu-se que, nas condi??es analisadas, o m?todo auxiliar de diagn?stico (DIAGNOdent?) ? um m?todo acurado na predi??o de c?rie de dentina em dentes dec?duos. Al?m disso, o m?todo comprovou que o padr?o usual de remo??o de dentina garante a remo??o do tecido cariado
20

Formation dynamique d'équipes dans les DEC-POMDPS ouverts à base de méthodes Monte-Carlo / Dynamic team formation in open DEC-POMDPs with Monte-Carlo methods

Cohen, Jonathan 13 June 2019 (has links)
Cette thèse traite du problème où une équipe d'agents coopératifs et autonomes, évoluant dans un environnement stochastique partiellement observable, et œuvrant à la résolution d'une tâche complexe, doit modifier dynamiquement sa composition durant l'exécution de la tâche afin de s'adapter à l'évolution de celle-ci. Il s'agit d'un problème qui n'a été que peu étudié dans le domaine de la planification multi-agents. Pourtant, il existe de nombreuses situations où l'équipe d'agent mobilisée est amenée à changer au fil de l'exécution de la tâche.Nous nous intéressons plus particulièrement au cas où les agents peuvent décider d'eux-même de quitter ou de rejoindre l'équipe opérationnelle. Certaines fois, utiliser peu d'agents peut être bénéfique si les coûts induits par l'utilisation des agents sont trop prohibitifs. Inversement, il peut parfois être utile de faire appel à plus d'agents si la situation empire et que les compétences de certains agents se révèlent être de précieux atouts.Afin de proposer un modèle de décision qui permette de représenter ces situations, nous nous basons sur les processus décisionnels de Markov décentralisés et partiellement observables, un modèle standard utilisé dans le cadre de la planification multi-agents sous incertitude. Nous étendons ce modèle afin de permettre aux agents d'entrer et sortir du système. On parle alors de système ouvert. Nous présentons également deux algorithmes de résolution basés sur les populaires méthodes de recherche arborescente Monte-Carlo. Le premier de ces algorithmes nous permet de construire des politiques jointes séparables via des calculs de meilleures réponses successives, tandis que le second construit des politiques jointes non séparables en évaluant les équipes dans chaque situation via un système de classement Elo. Nous évaluons nos méthodes sur de nouveaux jeux de tests qui permettent de mettre en lumière les caractéristiques des systèmes ouverts. / This thesis addresses the problem where a team of cooperative and autonomous agents, working in a stochastic and partially observable environment towards solving a complex task, needs toe dynamically modify its structure during the process execution, so as to adapt to the evolution of the task. It is a problem that has been seldom studied in the field of multi-agent planning. However, there are many situations where the team of agents is likely to evolve over time.We are particularly interested in the case where the agents can decide for themselves to leave or join the operational team. Sometimes, using few agents can be for the greater good. Conversely, it can sometimes be useful to call on more agents if the situation gets worse and the skills of some agents turn out to be valuable assets.In order to propose a decision model that can represent those situations, we base upon the decentralized and partially observable Markov decision processes, the standard model for planning under uncertainty in decentralized multi-agent settings. We extend this model to allow agents to enter and exit the system. This is what is called agent openness. We then present two planning algorithms based on the popular Monte-Carlo Tree Search methods. The first algorithm builds separable joint policies by computing series of best responses individual policies, while the second algorithm builds non-separable joint policies by ranking the teams in each situation via an Elo rating system. We evaluate our methods on new benchmarks that allow to highlight some interesting features of open systems.

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