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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

Reproductive performance of Holstein cows treated with prostaglandin F2a, gonadotropin releasing hormone, and recombinant bovine Somatotropin

Pickin, Charles Benjamin 14 October 2004 (has links)
The objective of this study was to examine the effects of presynchronization and recombinant bovine somatotropin (rbST) on conception rates following a timed insemination (TAI) protocol in lactating dairy cows. A further objective included the evaluation of the efficacy of the Early Conception Factor (ECF) test kit. Recombinant bST may offer some benefit when used in conjunction with estrus synchronization and TAI. Presynchronization treatment consisted of two injections of PGF2α given 14 d apart, with the second dose administered 14 d prior to the initiation of a TAI protocol. A total of 216 lactating Holstein cows were presynchronized with PGF2α and then received GnRH (100μg) at 67 ± 7 d post partum (PP), administration of PGF2α (25 mg) 7 d later, another GnRH (100μg) administration 2 d after PGF2α, and were inseminated 8-18h later (OvSynch). First service conception rate (CR) was determined by rectal palpation at 42 ± 7 d after artificial insemination (AI). Treated cows (n=113) received rbST 67 ± 7 d PP whereas control cows (n = 113) were presynchronized without rbST. The cycling status of all cows was determined by paired milk P4 levels at 53 and 67 ± 7 d PP. No differences (P > 0.10) in conception rate were observed between control and rbST treated cows (44.7 and 40.7% respectively), nor was there any interaction of cyclicity and rbST. Milk samples were collected 7 d following AI for use in ECF test kit evaluation. Samples were stored at -20ºC (n=216) and at 5ºC (n=113) until assayed. Test results for frozen and refrigerated samples were compared to conception rates determined by rectal palpation at 42 ± 7 d after AI. The rate of false positive and negative results for frozen milk samples were 36.1 and 14.8% respectively, and 40.7 and 7.1% for refrigerated milk samples. Treatment with rbST at the time of the first GnRH injection of an OvSynch protocol did not significantly alter first service conception rates. Additionally, an acceptable 92.9% accuracy of the ECF test for the detection of open cows 7 d after AI using milk samples stored at 5ºC was obtained. / Master of Science
12

Sistema transmissor CMOS de Radar UWB por varredura eletrônica com arranjo de antenas Vivaldi. / Conceptual model of a CMOS UWB Radar transmitter by electronic scanning with Vivaldi array antenna.

Oliveira, Alexandre Maniçoba de 21 November 2012 (has links)
O objetivo deste trabalho é desenvolver um modelo conceitual de um sistema transmissor de pulsos eletromagnéticos de banda ultra-larga, capaz de realizar o controle da formação do feixe irradiado de forma totalmente eletrônica. Para isso, é proposto um sistema formado por quatro canais iguais e independentes, sendo que cada um é formado por um controlador de atraso programável, com o qual se pode ajustar a defasagem temporal entre os pulsos de cada canal, um gerador de pulso, capaz de sintetizar a quinta derivada do pulso Gaussiano a partir de uma nova proposta de topologia, e um arranjo de antenas do tipo planar de abertura exponencial conhecida como antena Vivaldi. O sistema proposto é apoiado por modelos matemáticos e simulações elétricas post-layout com variação dos parâmetros por Monte Carlo com os programas LTSpice 4 e Microwind 2.6, utilizando as regras de processo padrão CMOS 180nm e eletromagnética tridimensional com o uso do programa CST Microwave 2011. Os resultados obtidos nas simulações, comparados com propostas anteriores, indicam que realmente houve o controle da formação do feixe irradiado cujo lóbulo principal teve uma magnitude média de 11dBi com uma largura angular do feixe de 33º x 38º e possibilidade de variar os ângulos azimutal e de elevação de -15º a 9º e -18º a 6º, respectivamente, para uma frequência central de 6GHz. O pulso utilizado para estimular as antenas foi o pulso Gaussiano em sua quinta ordem de derivação, que teve como resultados médios de simulação uma amplitude de 90mVpp, uma largura de pulso de 370ps a uma taxa de repetição de 100MHz e uma frequência central de 6GHz. / This work aims to develop a conceptual model of the new Ultra Wide-band fifth-order derivative Gaussian pulse transmitter with Vivaldi antenna array for beamforming using the technique of timed-array. It is proposed a system formed by four equal and independent channels, each of which is formed by a programmable delay controller in which one can adjust the delay time between pulses of each channel, a pulse generator, capable to synthesize the fifth derivative of a Gaussian pulse using a new topology, and a planar Vivaldi antenna. The proposed system was supported by mathematical models and post-layout electrical simulations with parameters variation by Monte Carlo in programs LTSpice 4 and MicroWind 2.6 using the CMOS 180nm Standard process rules and using three-dimensional electromagnetic program CST Microwave 2011. The simulation results indicated that there was indeed control on the beam formation irradiated whose main lobe has an average magnitude of 11dBi with an angular width of the beam 33 x 38 (degrees square) and possibility of varying the angles of azimuth and elevation from -15 to 9 degrees and -18 to 6 degrees, respectively, at a center frequency of 6GHz. The pulse used to stimulate the antennas was the fifth order Gaussian one, which had the average results of a simulation 90mVpp amplitude, a pulse width 370ps to a 100MHz repetition rate and a center frequency of 6 GHz..
13

Sistema transmissor CMOS de Radar UWB por varredura eletrônica com arranjo de antenas Vivaldi. / Conceptual model of a CMOS UWB Radar transmitter by electronic scanning with Vivaldi array antenna.

Alexandre Maniçoba de Oliveira 21 November 2012 (has links)
O objetivo deste trabalho é desenvolver um modelo conceitual de um sistema transmissor de pulsos eletromagnéticos de banda ultra-larga, capaz de realizar o controle da formação do feixe irradiado de forma totalmente eletrônica. Para isso, é proposto um sistema formado por quatro canais iguais e independentes, sendo que cada um é formado por um controlador de atraso programável, com o qual se pode ajustar a defasagem temporal entre os pulsos de cada canal, um gerador de pulso, capaz de sintetizar a quinta derivada do pulso Gaussiano a partir de uma nova proposta de topologia, e um arranjo de antenas do tipo planar de abertura exponencial conhecida como antena Vivaldi. O sistema proposto é apoiado por modelos matemáticos e simulações elétricas post-layout com variação dos parâmetros por Monte Carlo com os programas LTSpice 4 e Microwind 2.6, utilizando as regras de processo padrão CMOS 180nm e eletromagnética tridimensional com o uso do programa CST Microwave 2011. Os resultados obtidos nas simulações, comparados com propostas anteriores, indicam que realmente houve o controle da formação do feixe irradiado cujo lóbulo principal teve uma magnitude média de 11dBi com uma largura angular do feixe de 33º x 38º e possibilidade de variar os ângulos azimutal e de elevação de -15º a 9º e -18º a 6º, respectivamente, para uma frequência central de 6GHz. O pulso utilizado para estimular as antenas foi o pulso Gaussiano em sua quinta ordem de derivação, que teve como resultados médios de simulação uma amplitude de 90mVpp, uma largura de pulso de 370ps a uma taxa de repetição de 100MHz e uma frequência central de 6GHz. / This work aims to develop a conceptual model of the new Ultra Wide-band fifth-order derivative Gaussian pulse transmitter with Vivaldi antenna array for beamforming using the technique of timed-array. It is proposed a system formed by four equal and independent channels, each of which is formed by a programmable delay controller in which one can adjust the delay time between pulses of each channel, a pulse generator, capable to synthesize the fifth derivative of a Gaussian pulse using a new topology, and a planar Vivaldi antenna. The proposed system was supported by mathematical models and post-layout electrical simulations with parameters variation by Monte Carlo in programs LTSpice 4 and MicroWind 2.6 using the CMOS 180nm Standard process rules and using three-dimensional electromagnetic program CST Microwave 2011. The simulation results indicated that there was indeed control on the beam formation irradiated whose main lobe has an average magnitude of 11dBi with an angular width of the beam 33 x 38 (degrees square) and possibility of varying the angles of azimuth and elevation from -15 to 9 degrees and -18 to 6 degrees, respectively, at a center frequency of 6GHz. The pulse used to stimulate the antennas was the fifth order Gaussian one, which had the average results of a simulation 90mVpp amplitude, a pulse width 370ps to a 100MHz repetition rate and a center frequency of 6 GHz..
14

Model based analysis of time-aware web services interactions

Ponge, Julien Nicolas, Computer Science & Engineering, Faculty of Engineering, UNSW January 2009 (has links)
Web services are increasingly gaining acceptance as a framework for facilitating application-to-application interactions within and across enterprises. It is commonly accepted that a service description should include not only the interface, but also the business protocol supported by the service. The present work focuses on the formalization of the important category of protocols that include time-related constraints (called timed protocols), and the impact of time on compatibility and replaceability analysis. We formalized the following timing constraints: CInvoke constraints define time windows of availability while MInvoke constraints define expirations deadlines. We extended techniques for compatibility and replaceability analysis between timed protocols by using a semantic-preserving mapping between timed protocols and timed automata, leading to the novel class of protocol timed automata (PTA). Specifically, PTA exhibit silent transitions that cannot be removed in general, yet they are closed under complementation, making every type of compatibility or replaceability analysis decidable. Finally, we implemented our approach in the context of a larger project called ServiceMosaic, a model-driven framework for web service life-cycle management.
15

Model Checking Parameterized Timed Systems

Mahata, Pritha January 2005 (has links)
<p>In recent years, there has been much advancement in the area of verification of infinite-state systems. A system can have an infinite state-space due to unbounded data structures such as counters, clocks, stacks, queues, etc. It may also be infinite-state due to parameterization, i.e., the possibility of having an arbitrary number of components in the system. For parameterized systems, we are interested in checking correctness of all the instances in one verification step. </p><p>In this thesis, we consider systems which contain both sources of infiniteness, namely: (a) real-valued clocks and (b) parameterization. More precisely, we consider two models: (a) the timed Petri net (TPN) model, which is an extension of the classical Petri net model; and (b) the timed network (TN) model in which an arbitrary number of timed automata run in parallel. </p><p>We consider verification of safety properties for timed Petri nets using forward analysis. Since forward analysis is necessarily incomplete, we provide a semi-algorithm augmented with an acceleration technique in order to make it terminate more often on practical examples. Then we consider a number of problems which are generalisations of the corresponding ones for timed automata and Petri nets. For instance, we consider zenoness where we check the existence of an infinite computation with a finite duration. We also consider two variants of boundedness problem: syntactic boundedness in which both live and dead tokens are considered and semantic boundedness where only live tokens are considered. We show that the former problem is decidable while the latter is not. Finally, we show undecidability of LTL model checking both for dense and discrete timed Petri nets. </p><p>Next we consider timed networks. We show undecidability of safety properties in case each component is equipped with two or more clocks. This result contrasts previous decidability result for the case where each component has a single clock. Also ,we show that the problem is decidable when clocks range over the discrete time domain. This decidability result holds when the processes have any finite number of clocks. Furthermore, we outline the border between decidability and undecidability of safety for TNs by considering several syntactic and semantic variants.</p>
16

Model Checking Parameterized Timed Systems

Mahata, Pritha January 2005 (has links)
In recent years, there has been much advancement in the area of verification of infinite-state systems. A system can have an infinite state-space due to unbounded data structures such as counters, clocks, stacks, queues, etc. It may also be infinite-state due to parameterization, i.e., the possibility of having an arbitrary number of components in the system. For parameterized systems, we are interested in checking correctness of all the instances in one verification step. In this thesis, we consider systems which contain both sources of infiniteness, namely: (a) real-valued clocks and (b) parameterization. More precisely, we consider two models: (a) the timed Petri net (TPN) model, which is an extension of the classical Petri net model; and (b) the timed network (TN) model in which an arbitrary number of timed automata run in parallel. We consider verification of safety properties for timed Petri nets using forward analysis. Since forward analysis is necessarily incomplete, we provide a semi-algorithm augmented with an acceleration technique in order to make it terminate more often on practical examples. Then we consider a number of problems which are generalisations of the corresponding ones for timed automata and Petri nets. For instance, we consider zenoness where we check the existence of an infinite computation with a finite duration. We also consider two variants of boundedness problem: syntactic boundedness in which both live and dead tokens are considered and semantic boundedness where only live tokens are considered. We show that the former problem is decidable while the latter is not. Finally, we show undecidability of LTL model checking both for dense and discrete timed Petri nets. Next we consider timed networks. We show undecidability of safety properties in case each component is equipped with two or more clocks. This result contrasts previous decidability result for the case where each component has a single clock. Also ,we show that the problem is decidable when clocks range over the discrete time domain. This decidability result holds when the processes have any finite number of clocks. Furthermore, we outline the border between decidability and undecidability of safety for TNs by considering several syntactic and semantic variants.
17

Model based analysis of time-aware web services interactions

Ponge, Julien Nicolas, Computer Science & Engineering, Faculty of Engineering, UNSW January 2009 (has links)
Web services are increasingly gaining acceptance as a framework for facilitating application-to-application interactions within and across enterprises. It is commonly accepted that a service description should include not only the interface, but also the business protocol supported by the service. The present work focuses on the formalization of the important category of protocols that include time-related constraints (called timed protocols), and the impact of time on compatibility and replaceability analysis. We formalized the following timing constraints: CInvoke constraints define time windows of availability while MInvoke constraints define expirations deadlines. We extended techniques for compatibility and replaceability analysis between timed protocols by using a semantic-preserving mapping between timed protocols and timed automata, leading to the novel class of protocol timed automata (PTA). Specifically, PTA exhibit silent transitions that cannot be removed in general, yet they are closed under complementation, making every type of compatibility or replaceability analysis decidable. Finally, we implemented our approach in the context of a larger project called ServiceMosaic, a model-driven framework for web service life-cycle management.
18

Timed Refinement for Verification of Real-Time Object Code Programs

Dubasi, Mohana Asha Latha January 2018 (has links)
Real-time systems such as medical devices, surgical robots, and microprocessors are safety- critical applications that have hard timing constraint. The correctness of real-time systems is important as the failure may result in severe consequences such as loss of money, time and human life. These real-time systems have software to control their behavior. Typically, these software have source code which is converted to object code and then executed in safety-critical embedded devices. Therefore, it is important to ensure that both source code and object code are error-free. When dealing with safety-critical systems, formal verification techniques have laid the foundation for ensuring software correctness. Refinement based technique in formal verification can be used for the verification of real- time interrupt-driven object code. This dissertation presents an automated tool that verifies the functional and timing correctness of real-time interrupt-driven object code programs. The tool has been developed in three stages. In the first stage, a novel timed refinement procedure that checks for timing properties has been developed and applied on six case studies. The required model and an abstraction technique were generated manually. The results indicate that the proposed abstraction technique reduces the size of the implementation model by at least four orders of magnitude. In the second stage, the proposed abstraction technique has been automated. This technique has been applied to thirty different case studies. The results indicate that the automated abstraction technique can easily reduce the model size, which would in turn significantly reduce the verification time. In the final stage, two new automated algorithms are proposed which would check the functional properties through safety and liveness. These algorithms were applied to the same thirty case studies. The results indicate that the functional verification can be performed in less than a second for the reduced model. The benefits of automating the verification process for real-time interrupt-driven object code include: 1) the overall size of the implementation model has reduced significantly; 2) the verification is within a reasonable time; 3) can be applied multiple times in the system development process. / Several parts of this dissertation was funded by a grant from the United States Government and the generous support of the American people through the United States Department of State and the United States Agency for International Development (USAID) under the Pakistan – U.S. Science & Technology Cooperation Program. The contents do not necessarily reflect the views of the United States Government.
19

Verification of Stochastic Timed Automata / Vérification des automates temporisés et stochastiques

Carlier, Pierre 08 December 2017 (has links)
La vérification est maintenant une branche très connue des sciences informatiques. Elle est cruciale lorsque l'on a affaire à des programmes informatiques dans des systèmes automatiques : on veut vérifier si un système donné est correct et s'il satisfait des propriétés nécessaires à son bon fonctionnement. Une façon d'analyser ces systèmes se fait par la modélisation mathématique. La question est alors : peut-on vérifier si le modèle satisfait les propriétés requises ? C'est ce que l'on appelle le problème du model-checking. Plusieurs modèles ont été étudiés dans la littérature. Nous portons notre intérêt sur des modèles qui peuvent mêler des aspects temporels et des aspects probabilistes. Dans cette thèse, nous étudions donc le modèle des automates temporisés et stochastiques (ATS). Les contributions de ce document sont divisées en deux parties. Tout d'abord, nous étudions les problèmes de model-checking qualitatifs et quantitatifs des ATS. Les ATS sont, en particulier, des systèmes probabilistes généraux et avec de tels modèles, on est intéressé par des questions du type : « Une propriété est-elle satisfaite, au sein d'un modèle donné, avec probabilité 1 ? » (qualitatif) ou bien « Peut-on calculer une approximation de la probabilité que le modèle satisfait une propriété donnée ? » (quantitatif).Nous étudions ces questions dans des systèmes probabilistes généraux en utilisant, entre autres, la notion de decisiveness utilisée dans les chaînes de Markov infinie dans le but d'obtenir d'importants résultats qualitatifs et que nous étendons ici dans notre contexte plus général. Nous prouvons plusieurs résultats pour les problèmes de model-checking qualitatifs et quantitatifs de ces systèmes probabilistes, certains d'entre eux étant des extensions de travaux antérieurs sur les chaînes de Markov, d'autres étant nouveaux, et nous montrons comment l'on peut appliquer ces résultats sur des sous-classes des ATS. Nous étudions ensuite la vérification compositionnelle des ATS. En général, un système est le résultat de plusieurs plus petits systèmes fonctionnant ensemble. La vérification compositionnelle permet alors de réduire l'analyse de gros systèmes aux analyses des plus petits systèmes qui le composent. Il est donc crucial d'avoir une bonne structure compositionnelle au sein des modèles mathématiques, et cela manque aux ATS. Dans cette thèse, nous définissons un opérateur de composition pour les ATS. Nous faisons d'abord l'hypothèse que les ATS composés fonctionnent complètement indépendamment l'un de l'autre, c'est-à-dire les ATS ne communiquent pas entre eux. Nous prouvons que notre définition satisfait bien cette hypothèse d'indépendance. Un tel opérateur de composition n'est pas très intéressant puisque, généralement, les systèmes interagissent entre eux. Mais c'est une première étape nécessaire. Nous introduisons donc le nouveau modèle des ATS interactifs (ATSI) qui vont permettre des interactions entre les systèmes. Nous définissons un opérateur de composition dans les ATSI qui va rendre possible des synchronisations entre les systèmes et qui est construit sur la précédente composition dans les ATS. Nous finissons cette thèse par l'identification d'une sous-classe de ATSI dans laquelle tous les résultats qualitatifs et quantitatifs fournis dans cette thèse peuvent être appliqués, et qui est donc accompagnée d'une bonne structure compositionnelle au sein du modèle. / Verification is now a well-known branch in computer science. It is crucial when dealing with computer programs in automatic systems: we want to check if a given system is correct and satisfies some specifications that should be met. One way to analyse those systems is to model them mathematically. The question is then: can we check if the model satisfies the required specifications ? This is called the model-checking problem. Several models have been studied in the literature. We have an interest for models that can mix both timing and randomized aspects. In this thesis we thus study the stochastic timed automaton model (STA). The contributions of this document are twofold. First, we study the qualitative and quantitative model-checking problems of STA. STA are, in particular, general probabilistic systems and with such model, one is thus interested in questions like « Is a property satisfied, within a given model, with probability 1 ? » (qualitative) or « Can we compute an approximation of the probability that the model satisfies a given property ? » (quantitative).We study those questions for general stochastic systems using, amongst other, the notion of decisiveness used in infinite Markov chains in order to get strong qualitative and quantitative results, and that we extend here in or more general context. We prove several results for the qualitative and quantitative model-checking problems of those probabilistic systems, some of them being extensions of previous work on Markov chains, others being new, and we show how it can be applied to subclasses of STA. Then we study the compositional verification in STA. In general, a system is the result of several smaller systems working together. Compositional verification allows then one to reduce the analysis of a big system to the analyses of the smaller systems which compose it. It is then crucial to have a good compositional framework in mathematical models, and this lacks in STA. In this thesis, we define an operator of composition for STA. We first make the assumption that the STA composed run completely independently from each other, i.e. they do not communicate between them. We prove that our definition satisfies indeed this independence assumption. Such an operator of composition is not very interesting as in general, systems do communicate. But it is a necessary first step. We then introduce the new model of interactive STA (ISTA) that will allow for interactions between the systems. We define an operator of composition in ISTA that will make synchronisations possible between the systems and that is built on the previous composition in STA. We end this thesis with the identification of a subclass of ISTA in which all the qualitative and quantitative results provided in this thesis can be applied, and which thus comes with the nice compositional framework defined in the model.
20

Probabilistic guarantees in model-checking with Time Petri Nets

Lecart, Manon January 2023 (has links)
With the prevalence of technology and computer systems in today’s society, it is crucial to ensure that the systems we use are secure. The fields that study these issues, cybersecurity and cybersafety, use the formal verification technique of modelchecking. This paper tackles one aspect of the work needed to develop model-checking methods as we try to improve the efficiency and the reliability of model-checking techniques using the Time Petri Net model. Formal methods based on Time Petri Nets are not exempt from the state-explosion problem, and we study here different approaches to circumvent this problem. In particular, we show that limiting the exploration of such a model to runs with integer dates maintains the integrity of the model-checking result. We also show that it is possible to set a limit on the number of runs that can be explored while maintaining the probability that the observation is correct above a certain threshold. / Med tanke på hur vanligt det är med teknik och datorsystem i dagens samhälle är det viktigt att se till att de system vi använder är säkra. De områden som studerar dessa frågor, cybersäkerhet och cybersafety, använder den formella verifieringstekniken modellkontroll. Denna artikel tar upp en aspekt av det arbete som krävs för att utveckla metoder för modellkontroll, eftersom vi försöker förbättra effektiviteten och tillförlitligheten hos metoder för modellkontroll med hjälp av Time Petri Netmodellen. Formella metoder baserade på Time Petri Nets är inte undantagna från problemet med tillståndsexplosion, och vi studerar här olika tillvägagångssätt för att kringgå detta problem. I synnerhet visar vi att om man begränsar utforskningen av en sådan modell till körningar med heltalsdatum bibehålls integriteten hos resultatet av modellkontrollen. Vi visar också att det är möjligt att sätta en gräns för antalet körningar som kan utforskas samtidigt som sannolikheten för att observationen är korrekt hålls över ett visst tröskelvärde.

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