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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

Contribution à l'analyse de performances des Systèmes à Evénements Discrets non linéaires dans l'algèbre (min,+) / Contribution to the performance analysis of nonlinear Discrete Events Systems in (min, +) algebra

Benfekir, Abderrahim 19 December 2013 (has links)
Cette thèse s'inscrit dans le cadre de la théorie des systèmes linéaires dans les dioïdes. Cette théorie concerne la sous-classe des systèmes à événements discrets modélisables par les Graphes d'Événements Temporisés (GET). La dynamique de ces graphes peut être représentée par des équations récurrentes linéaires sur des structures algébriques particulières telles que l'algèbre (max,+) ou l'algèbre (min,+).Ce mémoire est consacré à l'analyse de performances des systèmes dynamiques qui peuvent être modélisés graphiquement par des Graphes d'Événements Temporisés Généralisés (GETG). Ces derniers, contrairement au GET, n'admettent pas une représentation linéaire dans l'algèbre (min,+). Pour pallier à ce problème de non linéarité, nous avons utilisé une approche de modélisation définie sur un dioïde d'opérateurs muni de deux lois internes : loi additive correspondant à l'opération (min), et loi multiplicative équivalente à la loi de composition usuelle. Le modèle d'état obtenu, est utilisé pour évaluer les performances des GETG. Pour cela, nous avons proposé une nouvelle méthode qui a pour but de linéariser le modèle mathématique régissant l'évolution dynamique du modèle graphique, dans le but d'obtenir un modèle (min,+) linéaire. La deuxième partie de cette thèse est consacrée au problème qui consiste à déterminer les ressources à utiliser dans une ligne de production, en vue d'atteindre des performances souhaitée. Ceci est équivalent à déterminer le marquage initial de la partie commande du GETG. / This thesis is part of the theory of linear systems over dioids. This theory concerns the subclass of discrete event dynamic systems modeled by Timed Event Graphs (TEG). The dynamics of these graphs can be represented by linear recurrence equations over specific algebraic structures such as (max,+) algebra or (min,+) algebra.This report is devoted to the performance analysis of dynamic systems which can be represented graphically by Generalized Timed Event Graphs(GTEG). These type of graphs, unlike TEG, do not admit a linear representation in (min,+) algebra. To mitigate the problem of nonlinearity, we used a modeling approach defined on a dioid operators. The obtained state model is used to evaluate the performance of GTEG. For this, we proposed a new method to linearize the mathematical model governing the dynamic evolution of the graphical model in order to obtain a linear model in (min,+) algebra. The second part of this work is devoted to the problem of determining the resources to use in a production line, in order to achieve desired performance. These is equivalent to determining the initial marking of the control part of the GTEG.
52

Towards A Practice Theory of Goal-setting: Assessing the theoretical goal-setting of The Leprosy Mission in Nigeria

Ogbeiwi, Osahon J.I. January 2019 (has links)
Goal-setting is indispensable for effective healthcare management. Yet, literature evidence suggests many organisations worldwide do not know how to formulate ‘SMART’ goals. Evidence of how existing theories work in practice is scarce, and the practices in low-income countries are unknown. Therefore, this research explored how leprosy project goals were formulated to describe the theoretical practice framework of The Leprosy Mission Nigeria (TLMN). Using a case-study design, ten managers were interviewed individually concerning their goal-setting knowledge, experience and perspective; and documented goals of six projects were reviewed. A five-step constructionist thematic data analysis generated eleven theoretical frameworks from the concepts of the emergent core themes of ‘stakeholders’, ‘strategies’ and ‘statements.’ Further theorisation reduced them to one general framework. This revealed TLMN’s goal-setting practice as a four-stage centre-led, top-down, beneficiary-focused and problem-based process. The stages were national preparation, baseline needs-survey, centralised goal formulation and nationalised planning. The outcome was the formulation of assigned, ‘non SMART’ objective statements, which are then used for planning projects. Other theoretical models constructed included a Goal Effects Cycle, ‘SMARTA’ goal attributes and hierarchical criteria for differentiating goal-types. A theory developed from TLMN goal-setting postulates that: ‘Assigned non SMART goal formulation directly results from centralised goal-setting practice and is the predictor of unrealistic project planning.’ Therefore, I propose that goal statements will be ‘SMARTA’ and plans, more realistic and relevant if goal setting is done collaboratively by all stakeholders at all stages of the process. Also, ‘Change-Beneficiary-Indicator-Target-Timeframe’ and ‘Change- Beneficiary-Location-Timeframe’ frameworks are recommended as templates for writing SMART objectives and aims respectively.
53

From Timed Models to Timed Implementations

De Wulf, Martin 20 December 2006 (has links)
<p align="justify">Computer Science is currently facing a grand challenge : finding good design practices for embedded systems. Embedded systems are essentially computers interacting with some physical process. You could find one in a braking systems or in a nuclear power plant for example. They present several design difficulties : first they are reactive systems, interacting indefinitely with their environment. Second,they must satisfy real-time constraints specifying when they should respond, and not only how. Finally, their environment is often deeply continuous, presenting complex dynamics. The formal models of choice for specifying such systems are timed and hybrid automata for which model checking is pretty well studied.</p> <p align="justify">In a first part of this thesis, we study a complete design approach, including verification and code generation, for timed automata. We have to define a new semantics for timed automata, the AASAP semantics, that preserves the decidability properties for model checking and at the same time is implementable. Our notion of implementability is completely novel, and relies on the simulation of a semantics that is obviously implementable on a real platform. We wrote tools for the analysis and code generation and exemplify them on a case study about the well known Philips Audio Control Protocol.</p> <p align="justify">In a second part of this thesis, we study the problem of controller synthesis for an environment specified as a hybrid automaton. We give a new solution for discrete controllers having only an imperfect information about the state of the system. In the process, we defined a new algorithm, based on the monotonicity of the controllable predecessors operator, for efficiently finding a controller and we show some promising applications on a classical problem : the universality test for finite automata.
54

Robustness in timed automata : analysis, synthesis, implementation / Robustesse dans les automates temporisés : analyse, synthèse, implémentation

Sankur, Ocan 24 May 2013 (has links)
Les automates temporisés sont un formalisme qui permet de modéliser, vérifier, et synthétiser des systèmes temps-réels. Ils sont dotés d’une sémantique abstraite et mathé- matique, qui permet de formaliser et résoudre plusieurs problèmes de vérification et de synthèse. Cependant, les automates temporisés sont utilisés pour concevoir des modèles, plutôt que décrire des systèmes temps-réels entiers. Ainsi, une fois la phase de conception terminée, il reste à déterminer si les comportements du modèle correspondent à ceux d’un vrai système. Une étape importante de l’implémentation consiste à s’assurer de la robustesse du système. On considère une notion de robustesse sur les automates tem- porisés qui exige que les comportements soient préservés quand le modèle est sujet à des perturbations bornées. Dans cette thèse, plusieurs approches sont étudiées : Dans l’analyse de robustesse, on se demande si un automate temporisés donné préserve ses com- portements sous divers types de perturbations, et on cherche à calculer un majorant sur les perturbations tolérées. La synthèse robuste s’intéresse au calcul d’une loi de contrôle (ou une stratégie) qui guide le système, et tolère des perturbations d’une magnitude calculable. Enfin, dans l’implémentation robuste, on s’intéresse à transformer automatiquement un modèle donné pour le rendre robuste, tout en préservant ses comportements. Plusieurs modèles de perturbations sont considérés : erreurs de mesure de temps (élargissement de gardes), élimination des comportements limites (contraction de gardes), et la restriction du domaine du temps aux valeurs discrètes. On formalise également les problèmes de synthèse robuste comme des jeux entre le contrôleur et un environnement qui perturbe systèmatiquement tout délai choisi par une quantité bornée. Ces problèmes sont étudiés pour les automates temporisés, ainsi que leurs extensions- les jeux temporisés, et les automates et jeux temporisés pondérés. Plusieurs algorithmes d’analyse de robustesse parametrée contre l’élargissement de gardes et la contraction de gardes sont proposés. Deux variantes de la sémantique de jeu pour le problème de synthèse robuste sont également étudiées pour les automates temporisés et leurs extensions. Un logiciel d’analyse de robustesse contre la contraction de gardes, ainsi que des résultats expérimentaux sont présentés. Le problème de l’implémentation robuste est étudié dans deux contextes différents. Tous les algorithmes calculent également un majorant sur les perturbations que le modèle donné est capable de tolérer. / Timed automata are a formalism to model, verify, and synthesize real-time systems. They have the advantage of having an abstract mathematical semantics, which allow formalizing and solving several verification and synthesis problems. However, timed automata are intended to design models, rather than completely describe real systems. Therefore, once the design phase is over, it remains to check whether the behavior of an actual implementation corresponds to that of the timed automaton model. An important step before implementing a system design is ensuring its robustness. This thesis considers a notion of robustness that asks whether the behavior of a given timed automaton is preserved, or can be made so, when it is subject to small perturbations. Several approaches are considered: Robustness analysis seeks to decide whether a given timed automaton tolerates perturbations, and in that case to compute the (maximum) amount of tolerated perturbations. In robust synthesis, a given system needs to be controlled by a law (or strategy) which tolerates perturbations upto some computable amount. In robust implementation, one seeks to automatically transform a given timed automaton model so that it tolerates perturbations by construction. Several perturbation models are considered, ranging from introducing error in time measures (guard enlargement), forbidding behaviors that are too close to boundaries (guard shrinking), and restricting the time domain to a discrete sampling. We also formalize robust synthesis problems as games, where the control law plays against the environment which can systematically perturb the chosen moves, by some bounded amount. These problems are studied on timed automata and their variants, namely, timed games, and weighted timed automata and games. Algorithms for the parameterized robustness analysis against guard enlargements, and guard shrinkings are presented. The robust synthesis problem is studied for two variants of the game semantics, for timed automata, games, and their weighted extensions. A software tool for robustness analysis against guard shrinkings is presented, and experimental results are discussed. The robust implementation problem is also studied in two different settings. In all algorithms, an upper bound on perturbations that the given timed automaton tolerates can be computed.
55

Presynchronizing injections of prostaglandin F[subscript]2alpha[subscript] or prostaglandin F[subscript]2alpha[ subscript + Gonadotropin-releasing hormone before a fixed time artificial insemination CO-Synch + CIDR program in suckled beef cows

Hill, Scott L. January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Jeffrey S. Stevenson / We hypothesized that pregnancy outcomes may be improved by inducing luteal regression, ovulation, or both before a control CO-Synch + CIDR program (100 mcg GnRH i.m. [GnRH-1] and insertion of a progesterone-impregnated intravaginal controlled internal drug release [CIDR] insert on d -10, 25 mg PGF2alpha (PG) i.m. and CIDR insert removal on d -3, and 100 mcg GnRH i.m. [GnRH-2] and timed AI [TAI] on d 0) in suckled beef cows. This hypothesis was tested in 2 experiments, in which cows were treated with either PG or PG + GnRH before initiating a control CO-Synch + CIDR program to increase the proportion of cows starting the program in a low (< 1 ng/mL; Exp. 1) or high (≥ 1 ng/mL; Exp. 2) progesterone status, respectively. Blood was collected before each injection for later progesterone analyses. In Exp. 1, cows at 9 locations (n = 1,537) were assigned to either: (1) control or (2) PrePG (same as control with a PG injection on d -13). The PrePG cows had larger (P < 0.05) follicles on d -10 and more (P < 0.05) ovulated after GnRH-1 than controls (60.6 vs. 36.5%). Incidence of estrus between d -3 and 0 was greater (P < 0.05) for treated multiparous cows than multiparous controls and treated and control primiparous cows (74.1 vs. 64.3, 58.6, and 59.1%, respectively). In Exp. 2, cows at 4 locations (n = 803) were assigned to: (1) control (same as Exp. 1) or (2) PrePGG (same as control with PG injection on d -20 and GnRH injection on d -17. Cows with BCS > 5.0 or ≥ 70 d postpartum at TAI were more (P < 0.05) likely to become pregnant than thinner cows or those with fewer days postpartum. Treated cows in both experiments were more (P < 0.05) likely than controls to have luteolysis after initial PG injections and reduced (P < 0.05) serum progesterone. In both experiments, pregnancy rates at d 35 did not differ between treatment and control; however, cows classified as anestrous before d -10, but with elevated progesterone on d -10, had increased (P < 0.05) pregnancy outcomes than remaining anestrous cows with low progesterone concentrations. In summary, luteal regression and ovulation were enhanced by treatments before the 7 d CO-Synch + CIDR program; however, pregnancy per TAI was not improved.
56

Taxa de prenhez em vacas Nelore pós-parto, submetidas ou não a aplicação de eCG 2 dias antes e/ou 14 dias após a IATF / Pregnancy rate in portpartum Nelore cows treated or not with eCG 2 days before and/or 14 days after TAI

Lemes, Amanda Prudêncio 02 October 2012 (has links)
O presente trabalho foi delineado com o intuito de identificar os efeitos da inclusão da Gonadotrofina Coriônica Equina (eCG) antes e após a IA em vacas de corte submetidas a protocolos de IATF e conduzido na Fazenda Rancho 60, pertencente ao Grupo Agropecuária Fazenda Brasil (Barra do Garças, MT, Brasil). Para tanto, 901 vacas Nelores multíparas com média de 44 dias pós-parto foram sincronizadas, inseminadas em tempo fixo utilizando-se três touros (Aberdeen Angus) e nove inseminadores. Além disso, as vacas foram monitoradas por exames ultrassonográficos e/ou colheitas de sangue até os 30 dias após a IA. Taxas de sincronização, prenhez aos 30 e 60 dias foram mensuradas e as amostras de sangue foram avaliadas quanto à concentração de progesterona sérica. Foram avaliados os efeitos da inclusão de 300 UI de gonadotrofina coriônica equina (eCG) 2 dias antes e/ou 14 dias depois da IA e posteriormente avaliou-se também a influência do grupo genético e sexo dos bezerros no desempenho reprodutivo. Em suma, o tratamento com eCG após a IA não melhorou a fertilidade em vacas Nelore pós-parto, entretanto pode-se observar um incremento nas taxas de ovulação, prenhez aos 60 dias e aumento nas concentrações séricas de P4 nos animais que receberam eCG no D8. Quanto à influência da progênie na fertilidade das mães conclui-se que pode haver uma relação entre o sexo e raça dos bezerros na concentração circulante de P4 das progenitoras, entretanto estas variáveis não influenciaram na fertilidade da vaca submetida à IATF no período pós-parto. / The present work was designed to identify the effects of a treatment with equine chorionic gonadotropin (eCG) before and post-AI in beef cows submitted to TAI protocols. The experiment was conducted at Rancho 60 Farm, belonging to Grupo Agropecuaria Fazenda Brasil (Barra do Garças, MT, Brazil). For this, 901 multiparous Nellore cows with 44 days post-partum were synchronized, inseminated at fixed time using semen of three bulls (Angus). In addition, cows were monitored by ovarian ultrasonography and/or blood sampling until 30 days post AI. Ovulation rate, and pregnancy rates at 30 and 60 days were evaluated and blood samples were analyzed for serum progesterone concentration. The effects of treatment with 300 IU of eCG 2 days before and/or 14 days after AI were evaluated, as well as the influence of the breed and gender of their calves in the reproductive performance. In general, treatment with eCG after AI did not improve fertility in post-partum Nelore cows, however, it was detected an improvement in ovulation rate and pregnancy rate at 60 days and an increase in serum progesterone concentrations in cows that received eCG at Day 8. There was no effect of gender and breed of calves on fertility of the dams; however these variables influenced circulating progesterone post AI.
57

COMPARISON OF CONCEPTION RATES IN BEEF CATTLE INSEMINATED WITH EITHER SEXEDULTRA™ SEX-SORTED SEMEN OR CONVENTIONAL SEMEN IN FIXED-TIME ARTIFICIAL INSEMINATION (FTAI) PROTOCOLS

Crites, Benjamin R. 01 January 2017 (has links)
Estrous synchronization and artificial insemination (ESAI) are reproductive technologies that cattlemen can use to improve the reproductive performance of their herds. Controlling the gender ratio of the calf-crop can also improve the opportunity for increased revenue and profit. Producers are able to shift and/or control the gender ratio of their calf crop by incorporating sex-sorted semen into their AI programs. However, decreased conception rates to AI have been previously observed when sex-sorted semen was used in comparison to conventional semen of the same sires. The objective of the first study was to determine if conception rates will differ in females inseminated with conventional semen or SexedULTRA™ sex-sorted semen when estrus is synchronized using an industry-standard, 7-d CO-Synch + Controlled Internal Drug Release (CIDR) protocol for fixed-time artificial insemination (FTAI). The objective of the second study was to determine if conception rate to FTAI differs between SexedULTRA™ sex-sorted and conventional semen when yearling beef heifers are synchronized using a 14-d controlled internal drug release (CIDR) - PGF2α (PGF) protocol modified to optimize the control of ovulation and timing of insemination.
58

Global Thermospheric Response to Geomagnetic Storms

Suresh, Padmashri 01 May 2016 (has links)
Geomagnetic storms deposit energy and momentum into the Earth’s magnetosphere which in turn energizes the terrestrial atmosphere through Joule heating and particle precipitation. This storm energy predominantly converges at altitudes of 100 to 150 km, corresponding to the lower thermospheric region, which is then globally redistributed throughout the thermosphere. It is essential that we understand the times and magnitudes of this energy to understand the terrestrial atmospheric response to geomagnetic storms. However, our current knowledge is mostly limited to the studies of orbital altitudes of the thermosphere. We aim to fill this gap by conducting a statistical study of lower thermospheric response to geomagnetic storms. We use neutral temperature data from SABER (Sounding of the Atmosphere Using Broadband Emission Radiometry) instrument onboard the TIMED (Thermosphere, Ionosphere, and Mesosphere Energy Dynamics) satellite for this study. We devise a procedure to extract the storm response from SABER temperature measurements and deduce the magnitudes and times of the global storm energy redistribution in the 100 to 120 km altitude of the thermosphere. We use methods of inferential and descriptive statistics to investigate the lower thermospheric response for 145 storm intervals that occurred between 2002 and 2010. We also investigate the performance of the state-ofart physics and empirical models in replicating the lower thermosphere during geomagnetic storms.
59

Vérification de propriétés temporisées et hybrides: théorie et applications

Nickovic, Dejan 29 October 2008 (has links) (PDF)
Le développement croissant de systèmes embarqués de consommation, où les composants numériques, analogiques et logiciels sont combinés sur une même puce, résulte en une augmentation de la complexité des processus de conception et de vérification. La validation de tels systèmes analogiques et à signaux-mixtes reste largement basée sur des techniques de simulation, qui sont souvent combinées avec des méthodes d'analyse de nature ad-hoc. Cette thèse est motivée par l'exportation de méthodes formelles basées sur des propriétés, vers leur application à la validation de systèmes analogiques et à signaux mixtes, considérés à leur niveaux d'abstraction continu et temporisé.<br />Etant-donné que la vérification formelle de systèmes continus non-triviaux reste très difficile, nous nous tournons vers une méthode de validation plus légère appelée le monitoring basé sur des propriétés. Nous définissons signal temporal logic STL comme langage de spécification de haut niveau qui permet d'exprimer des propriétés temporelles de signaux continus et temporisés. STL est une extension de la logique de temps-réel metric interval temporal logic MITL, où les signaux continus sont transformés en signaux Booléens avec des prédicats numériques, et les relations temporelles entre ces signaux son exprimées avec les opérateurs temporels habituels dont les propositions atomiques correspondent à ces prédicats. Nous développons deux procédures de monitoring, une offline et une incrémantale, qui permettent de vérifier si les traces de simulations sont correctes par rapport aux propriétés STL. Les deux procédures sont implantées en outil de monitoring analogique AMT. Notre approche de monitoring basé sur des propriétés est appliquée, en utilisant AMT, à deux études de cas réalistes, où nous étudions des propriétés d'une mémoire de type FLASH et d'une interface de mémoire DDR2. <br />Nous considérons aussi le problème de vérification formelle de systèmes temporisés, et développons une traduction modulaire des formules MITL avec les opérateurs futurs et passés, vers des automates temporisés. La construction que nous proposons est basée sur les testeurs temporels, une classe spécifique d'automates avec les entrées et les sorties qui réalisent la fonction séquentielle définie par la sémantique des opérateurs MITL. Nous montrons d'abord comment chaque formule MITL peut être exprimée avec six opérateurs basiques (trois opérateurs passés et trois futurs) et nous proposons une construction de testeurs temporels à partir de ces opérateurs. Les testeurs temporels pour des formules MITL arbitraires sont obtenus en composant ces testeurs élémentaires.<br />Finalement, nous développons une procédure pour la synthèse automatique de contrôleurs à partir des spécifications de haut niveau exprimées avec le fragment borné de metric temporal logic (MTL). Nous proposons une traduction des propriétés spécifiées dans cette logique temporisée vers des automates temporisés déterministes, en supposant la variabilité bornée. Ensuite, nous pouvons appliquer à ces automates les algorithmes habituels de synthèse de sûreté pour construire un contrôleur qui satisfait la spécification par construction.
60

Instrumentation of timed automata for formal verification of timed properties

Hagman, Mikael January 2007 (has links)
<p>Embedded systems are used in many technical products of today. The tendency also points to the fact that they are in many ways becoming more and more complex as technology advances. Systems like advanced avionics, air bags, ABS brakes or any real-time embedded system requires reliability, correctness and timeliness. This puts hard pressure on designers, analyzers and developers. The need for high performance and non failing systems has therefore led to a growing interest in modeling and verification of component-based embedded systems in order to reduce costs and simplify design and development. The solution proposed by the Embedded Systems Lab at Linköping University is the modeling language PRES+, Petri Net based Representation for Embedded Systems.</p><p>PRES+ models are then translated into timed automata, TA, which is used by the UPPAAL verification tool. To be able to verify timing properties the translated TA model must be instrumented with certain timers, called clocks. These clocks must be reset in a manner reflected by the property to be verified.</p><p>This thesis will provide a solution to the problem and also give the reader necessary information in order to understand the theoretical background needed. The thesis will also show the reader the importance of modeling and time verification in the development of embedded systems. A simple example is used to describe and visualize the benefit regarding real-time embedded systems as well as the importance of the ability to verify these systems.</p><p>The conclusion drawn stresses the fact that high development costs, possible gain of human lives and the problems in developing complex systems only emphasize the need for easy to handle and intuitive verification methods.</p>

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