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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

Competição morfológica e ilhas de confiabilidade na morfologia derivacional

Quadros, Emanuel Souza de January 2015 (has links)
No domínio da morfologia derivacional, é difícil encontrar padrões de formação de palavras que possam se aplicar a todas as bases que se encaixam em seus contextos de aplicação. Isso equivale a dizer que a produtividade de padrões derivacionais costuma ser limitada. Entre as causas dessa limitação, vemos que formações potenciais são frequentemente bloqueadas por itens lexicais já existentes; em outros casos, elas são suplantadas por expressões formadas por padrões derivacionais concorrentes. Este trabalho dedica-se a explorar tais situações de competição. Iniciamos pelo exame da ideia de produtividade e de como entender as diferenças quantitativas entre padrões rivais quanto a este aspecto. Fazemos, em seguida, uma discussão mais detida da competição morfológica e da noção central de bloqueio, contrapondo às teorias gramaticais de base lexical uma abordagem pragmática deste fenômeno. Por fim, apresentamos o modelo desenvolvido em Albright e Hayes (1999) e em trabalhos posteriores, que explora a ideia de que o grau de confiabilidade do emprego de padrões morfológicos em diferentes contextos fonológicos é um fator determinante da produtividade desses padrões, bem como da competição entre eles. Testamos este modelo utilizando dados dos sufixos -ção e -mento, que se encontram em competição há bastante tempo no português. Estes dados provêm do Dicionário Houaiss 3.0 e de um levantamento de textos de jornais e blogs, coletados com o auxílio de programas computacionais desenvolvivdos para este trabalho. Nossos resultados sugerem que a manutenção da produtividade de -mento ao longo da história, mesmo após -ção ter se tornado o padrão dominante de nominalização, foi escorada pela existência de contextos fonológicos em que -mento atinge um alto grau de confiabilidade. Dada a produtividade da primeira conjugação, foram particularmente importantes os contextos de aplicação de -mento encontrados entre palavras desta classe verbal. Com base nestas generalizações, mostramos como um modelo estatístico é capaz de prever, na maior parte dos casos, a escolha entre estes dois afixos diante de uma nova base verbal. / In the field of derivational morphology, it is hard to find word formation patterns that may be applied to every base satisfying its context of application. This means that the productivity of derivational patterns is often limited. Among the causes of this limitation, we find that potential words are blocked by existing lexical items in many cases; in other cases, they are preempted by expressions formed by rival derivational patterns. This work devotes itself to exploring these instances of competition. We start by exploring the concept of productivity and by investigating how to understand quantitative differences between rival patterns in this respect. We then proceeed to a more detailed discussion of morphological competition and the fundamental notion of blocking, comparing a pragmatic approach to this phenomenon with lexicalist grammatical theories. Finally, we present the model of Albright e Hayes (1999) and later works, which explores the idea that the reliability of morphological patterns in different phonological contexts is a key determinant of the productivity of these patterns and the competition between them. We test this model on data formed by the suffixes -ção and -mento, which have been in competition for a long time in Portuguese. These data come from Dicionário Houaiss 3.0 and from a corpus created from newspapers and blogs with the help of software developed for this research. Our results suggest that the continued productivity of -mento throughout history, even after -ção had become the dominant nominalization pattern in the language, was supported by the existence of phonological contexts in which -mento reaches a high degree of reliability. Given the productivity of the first conjugation, contexts of application of -mento in words of this verbal class have shown to be especially important. We show that a statistical model equipped with these generalizations is able to predict the choice between these affixes in most cases.
62

Density and partition based clustering on massive threshold bounded data sets

Kannamareddy, Aruna Sai January 1900 (has links)
Master of Science / Department of Computing and Information Sciences / William H. Hsu / The project explores the possibility of increasing efficiency in the clusters formed out of massive data sets which are formed using threshold blocking algorithm. Clusters thus formed are denser and qualitative. Clusters that are formed out of individual clustering algorithms alone, do not necessarily eliminate outliers and the clusters generated can be complex, or improperly distributed over the data set. The threshold blocking algorithm, a current research paper from Michael Higgins of Statistics Department on other hand, in comparison with existing algorithms performs better in forming the dense and distinctive units with predefined threshold. Developing a hybridized algorithm by implementing the existing clustering algorithms to re-cluster these units thus formed is part of this project. Clustering on the seeds thus formed from threshold blocking Algorithm, eases the task of clustering to the existing algorithm by eliminating the overhead of worrying about the outliers. Also, the clusters thus generated are more representative of the whole. Also, since the threshold blocking algorithm is proven to be fast and efficient, we now can predict a lot more decisions from large data sets in less time. Predicting the similar songs from Million Song Data Set using such a hybridized algorithm is considered as the data set for the evaluation of this goal.
63

Hierarchical and partitioning based hybridized blocking model

Annakula, Chandravyas January 1900 (has links)
Master of Science / Department of Computing and Information Sciences / William H. Hsu / (Higgins, Savje, & Sekhon, 2016) Provides us with a sampling blocking algorithm that enables large and complex experiments to run in polynomial time without sacrificing the precision of estimates on a covariate dataset. The goal of this project is to run the different clustering algorithms on top of clusters formed from above mentioned blocking algorithm and analyze the performance and compatibility of the clustering algorithms. We first start with applying the blocking algorithm on a covariate dataset and once the clusters are formed, we then apply our clustering algorithm HAC (Hierarchical Agglomerative Clustering) or PAM (Partitioning Around Medoids) on the seeds of the clusters. This will help us to generate more similar clusters. We compare our performance and precision of our hybridized clustering techniques with the pure clustering techniques to identify a suitable hybridized blocking model.
64

Sensory transmission in peripheral neurons : effects of K+ channel blockers and autacoids

Spigelman, Igor January 1988 (has links)
Sensory transmission was studied in trigeminal root ganglia (TRG) of guinea pigs, using intracellular recording techniques. One approach was to examine in detail the effects of applications of different K⁺-channel blockers on the membrane voltage responses and outward currents of TRG neurons, in order to better understand the fundamental processes that affect their excitabilities and repetitive spike discharge. The second approach was to examine several endogenous substances for their effects on the excitabilities of TRG neurons. In addition, a strategy was developed for electrophysiological recording from neurons in human sympathetic ganglia. Successful investigations of these neurons revealed properties similar to certain reported characteristics of sympathetic neurons in experimental animals, including high (~29 MΩ input resistances, pharmacological sensitivity of spikes to the specific Na⁺-channel blocker tetrodotoxin (TTX, 1 µM) and to selective K⁺-channel blockers -- 4-aminopyridine (4-AP, 1 mM) and tetraethylammonium (TEA, 10 mM). The investigations demonstrated the potential value of these in vitro preparations for studies of the human condition. The investigations in TRG neurons demonstrated that bath applications of TEA (0.1-10 mM) and 4-AP (0.05-5 mM) or Cs⁺ applied internally from the recording electrode, produced an increase in input resistance and a decrease threshold for spike generation in all neurons. Also, applications of 4-AP increased subthreshold oscillations of the membrane potential and enhanced the repetitive spike firing evoked by intracellular injections of current pulses, or elicited spontaneous firing. In contrast, TEA or Cs⁺ applications blocked the oscillations and the spike afterhyperpolarizations (AHPs) without exaggerating repetitive discharge. These investigations suggestedthat several pharmacologically distinct K -currents contribute to the control of excitability in TRG neurons. Comparison of combined actions of 4-AP and TEA with those of Cs⁺, suggested that other ions in addition to K⁺ may contribute to postspike events. Single electrode voltage-clamp analyses revealed transient outward currents that were evoked at the termination of hyperpolarizing voltage commands from holding potentials near -40 mV. The activation was rapid (<5ms) and inactivation (T≃19 ms) complete at potentials within the activation range (-40 to -75 mV). During combined application of TTX (1 µM) and TEA (10 mM), fast activating, sustained currents (>1 s) were evoked by depolarizing commands from holding potentials near -70 mV. These currents were blocked completely by the additional applications of 4-AP (5 mM). Applications of TEA (0.1 mM to 10 mM) produced dose-dependent reductions of the transient outward currents. Applications of Cs⁺ also blocked the currents. However, administrations of 4-AP (0.05 to 5 mM) only slightly reduced these currents and high doses of muscarinic agonists had no effect. The high sensitivity to TEA, and not to 4-AP, suggest a fundamental distinction from similar currents observed previously in other neurons of vertebrates and invertebrates, and hence this transient outward current in TRG neurons, is termed I(T)- The kinetics of I(T) suggest its involvement in the spike AHPs. Therefore, blockade of I(T) by TEA may interfere indirectly with the re-activation of voltage-dependent Na⁺-channels, leading to decreases in repetitive discharge ability. The TEA-insensitive sustained outward current presumably has an inhibiting influence on repetitive discharge. Conditions that interfere with this current, such as blockade of K⁺-channels by 4-AP without a significant blockade of I(T), strongly favour the generation of repetitive discharge in TRG neurons. The investigations using electrical stimulation of axons revealed that changes in the resting potential could inhibit the invasion of spikes into the perikarya, or facilitate the generation of ectopic spike discharges. Applications of 4-AP (1 mM) facilitated the perikaryal invasion of spikes evoked by axonal stimulation, and also resulted in the appearance of fast (~10 ms) depolarizations that reached spike threshold in the absence of applied stimuli. These investigations provided direct evidence that the perikarya of sensory neurons are capable of spike generation, and suggest that this behavior may occur in normal or pathophysiological conditions. The most notable effects of autacoids were those of substance P and histamine, whereas bradykinin did not affect neuronal membrane properties. Applications of substance P in micromolar doses evoked large (up to 45 mV), reversible depolarizations in the majority of neurons, whereas histamine applications produced similar depolarizations only in a small portion of the TRG neurons. Increases in the repetitive discharge abilities of neurons were evident during substance P-induced depolarizations. Studies on the ionic mechanism of substance P action revealed that the peptide-applications resulted in activation of inward currents as well as blockade of outward currents. In addition, it was shown that Na⁺ and Mg²⁺ were involved in the mechanism of action. These findings represent the first demonstration of the profound actions of substance P on the perikaryal membranes of sensory neurons in mammals. The excitatory actions of this endogenous peptide also give rise to the possibility of physiological actions of substance P at multiple sites in the trigeminal system. / Medicine, Faculty of / Anesthesiology, Pharmacology and Therapeutics, Department of / Graduate
65

Exploration of variations of unrestricted blocking for description logics

Khodadadi, Mohammad January 2015 (has links)
Description logics are a family of logics that provide formalisms for representing and reasoning about knowledge, based on describing concepts, in a structured and formally well-understood way. They provide the logical foundation for the web ontology language (OWL), which increased awareness of them recently. The most popular techniques for decision procedures for description logics are tableau reasoning methods, which have a long tradition and are well established in automated reasoning. This thesis investigates the possibility of finding a general and optimised blocking mechanism for description logics with the finite model property. It suggests that, while the high branching factor for unrestricted blocking reduces its performance, suitable control of the application of the blocking rule can make the performance acceptable while preserving termination. This claim is supported by experiments that compare the performance of two sample controlled versions of unrestricted blocking. In order to show the generality and power of controlled versions of unrestricted blocking, it is shown how some of the mainstream and most successful standard blocking mechanisms can be approximated as restricted forms of unrestricted blocking. These approximations have the advantage of always being sound compared to their standard versions, which are known to be sound only for some logics. Here, a variation of unrestricted blocking which can ensure strong termination is also introduced. This is done through introducing a new rule that uses the inequality expressions introduced by the blocking rule. The weak termination property of unrestricted blocking is one of its weak points which by this variant of blocking can be addressed. The work presented in this thesis should be of value to people who are working on generalising different aspects of reasoning methods. As blocking plays a critical role in termination of tableau provers, exploration of different variations of unrestricted blocking introduced here may be also of interest for the artificial intelligence researcher.
66

Improvement of interconnection networks for clusters: direct-indirect hybrid topology and HoL-blocking reduction routing

Peñaranda Cebrián, Roberto 03 March 2018 (has links)
Nowadays, clusters of computers are used to solve computation intensive problems. These clusters take advantage of a large number of computing nodes to provide a high degree of parallelization. Interconnection networks are used to connect all these computing nodes. The interconnection network should be able to efficiently handle the traffic generated by this large number of nodes. Interconnection networks have different design parameters that define the behavior of the network. Two of them are the topology and the routing algorithm. The topology of a interconnection network defines how the different network elements are connected, while the routing algorithm determines the path that a packet must take from the source to the destination node. The most commonly used topologies typically follow a regular structure and can be classified into direct and indirect topologies, depending on how the different network elements are interconnected. On the other hand, routing algorithms can also be classified into two categories: deterministic and adaptive algorithms. To evaluate interconnection networks, metrics such as latency or network productivity are often used. Throughput refers to the traffic that the network is capable of accepting the network per time unit. On the other hand, latency is the time that a packet requires to reach its destination. This time can be divided into two parts. The first part is the time taken by the packet to reach its destination in the absence of network traffic. The second part is due to network congestion created by existing traffic. One of the effects of congestion is the so-called Head-of-Line blocking, where the packet at the head of a queue blocks, causing the remaining queued packets can not advance, although they could advance if they were at the head of the queue. Nowadays, there are other important factors to consider when interconnection networks are designed, such as cost and fault tolerance. On the one hand, a high performance is desirable, but without a disproportionate increase in cost. On the other hand, the fact of increasing the size of the network implies an increase in the network components, thus the probability of occurrence of a failure is higher. For this reason, having some fault tolerance mechanism is vital in current interconnection networks of large machines. Putting all in a nutshell, a good performance-cost ratio is required in the network, with a high level of fault-tolerance. This thesis focuses on two main objectives. The first objective is to combine the advantages of the direct and indirect topologies to create a new family of topologies with the best of both worlds. The main goal is the design of the new family of topologies capable of interconnecting a large number of nodes being able to get very good performance with a low cost hardware. The family of topologies proposed, that will be referred to as k-ary n-direct s-indirect, has a n dimensional structure where the k different nodes of a given dimension are interconnected by a small indirect topology of s stages. We will also focus on designing a deterministic and an adaptive routing algorithm for the family of topologies proposed. Finally we will focus on analyzing the fault tolerance in the proposed family of topologies. For this, the existing fault tolerance mechanism for similar topologies will be studied and a mechanism able to exploit the features of this new family will be designed. The second objective is to develop routing algorithms specially deigned to reduce the pernicious effect of Head-of-Line blocking, which may shoot up in systems with a high number of computing nodes. To avoid this effect, routing algorithms able of efficiently classifying the packets in the different available virtual channels are designed, thus preventing that the occurrence of a hot node (Hot-Spot) could saturate the network and affect the remaining network traffic. / Hoy en día, los clústers de computadores son usados para solucionar grandes problemas. Estos clústers aprovechan la gran cantidad de nodos de computación para ofrecer un alto grado de paralelización. Para conectar todos estos nodos de computación, se utilizan redes de interconexión de altas prestaciones capaces de manejar de forma eficiente el tráfico generado. Estas redes tienen diferentes parámetros de diseño que definen su comportamiento, de los cuales podríamos destacar dos: la topología y el algoritmo de encaminamiento. La topología de una red de interconexión define como se conectan sus componentes, mientras que el algoritmo de encaminamiento determina la ruta que un paquete debe tomar desde su origen hasta su destino. Las topologías más utilizadas suelen seguir una estructura regular y pueden ser clasificadas en directas e indirectas, dependiendo de cómo estén interconectados los diferentes elementos de la red. Por otro lado, los algoritmos de encaminamiento también pueden clasificarse en dos categorías: deterministas y adaptativos. Para evaluar estas redes se suelen utilizar medidas tales como la latencia o la productividad de la red. La productividad mide el tráfico que es capaz de aceptar la red por unidad de tiempo. La latencia mide el tiempo que utiliza un paquete para alcanzar su destino. Este tiempo se puede dividir en dos partes. La primera corresponde al tiempo utilizado por el paquete en alcanzar a su destino en ausencia de tráfico en la red. La segunda sería la debida a la congestión de la red creada por el tráfico existente. Uno de los efectos de la congestión es el denominado Head-of-Line blocking, donde el paquete que encabeza una cola se queda bloqueado, por lo que el resto de paquetes de la cola no pueden avanzar, aunque pudieran hacerlo si ellos encabezaran dicha cola. Otros factores a tomar en cuenta son el coste y la tolerancia a fallos. Las prestaciones deben mantenerse conforme aumentamos el tamaño de la red, pero sin un aumento prohibitivo en el coste. Además, el hecho de aumentar el tamaño de la red implica un aumento en el número de elementos de dicha red, aumentando la probabilidad de la aparición de un fallo. Por ello, es vital contar con algún mecanismo de tolerancia a fallos en las redes para los grandes supercomputadores actuales. En otras palabras, es de esperar una buena relación coste-prestaciones con un alto nivel de tolerancia a fallos. Esta tesis tiene dos objetivos principales. El primer objetivo combina las ventajas de las topologías directas e indirectas para crear una nueva familia de topologías con lo mejor de ambas. En concreto, nos centramos en el diseño de una nueva familia de topologías capaz de interconectar una gran cantidad de nodos siendo capaz de obtener muy buenas prestaciones con un bajo coste hardware. La familia de topologías propuesta, que hemos llamado k-ary n-direct s-indirect, tiene una estructura n-dimensional, donde los diferentes k nodos de una dimensión se conectan entre sí mediante una pequeña topología indirecta con s etapas. También diseñaremos un algoritmo de encaminamiento determinista y otro adaptativo para la familia de topologías propuesta. Finalmente, nos centraremos en estudiar la tolerancia a fallos para la familia de topologías propuesta. Para ello se estudiarán los mecanismos de tolerancia a fallos existentes en topologías similares y se diseñará un mecanismo capaz de aprovechar al máximo las características de esta nueva familia. El segundo objetivo consiste en el desarrollo de algoritmos de encaminamiento capaces de evitar el pernicioso efecto Head-of-Line blocking, lo cual puede aumentar rápidamente en sistemas con un gran número de nodos de computación. Para evitar este efecto se diseñarán algoritmos de encaminamiento capaces de clasificar de forma eficiente los paquetes en los diferentes canales virtuales disponibles, evitando así que la aparición de un punto caliente (Hot-Spot) sat / Hui en dia, els clústers de computadors són utilitzats per solucionar grans problemes computacionals. Aquests clústers aprofiten la gran quantitat de nodes de computació per a oferir un alt grau de paral·lelització. Per a connectar tots aquests nodes de computació, s'utilitzen xarxes d'interconnexió d'altes prestacions capaços de manejar de manera eficient el trànsit generat. Aquestes xarxes tenen diferents paràmetres de disseny que defineixen el seu comportament, dels quals podríem destacar dues: la topologia i l'algoritme d'encaminament. La topologia d'una xarxa d'interconnexió ens defineix com es connecten els seus components, mentre que l'algoritme d'encaminament determina la ruta que un paquet ha de prendre des del seu node origen fins al seu node destí. Les topologies més utilitzades solen seguir una estructura regular i poden ser classificades en directes i indirectes, depenent de com estiguen interconnectats els diferents elements de la xarxa. D'altra banda, els algoritmes d'encaminament també poden classificar-se en dues categories: deterministes i adaptatius. Per avaluar estes xarxes es solen utilitzar mesures com ara la latència o la productivitat de la xarxa. La productivitat mesura el trànsit que és capaç d'acceptar la xarxa per unitat de temps. La latència mesura el temps que utilitza un paquet per arribar al seu destí. Aquest temps es pot dividir en dues parts. La primera correspon al temps emprat pel paquet a aconseguir al seu destí en absència de trànsit a la xarxa. La segona part seria la deguda a la congestió de la xarxa creada per el trànsit existent. Un dels efectes de la congestió és l'anomenat Head-of-line blocking, on el paquet que encapçala una cua es queda bloquejat, de manera que la resta de paquets de la cua no poden avançar, encara que poguessen fer-ho si ells encapçalessen la dita cua. Altres factors a tenir en compte són el cost i la tolerància a fallades. Per tant, les prestacions s'han de mantenir d'acord augmentem la mida de la xarxa, però sense un augment prohibitiu en el cost. A més, el fet d'augmentar la mida de la xarxa implica un augment en el número de elements d'aquesta xarxa, de manera que la probabilitat de l'aparició d'una fallada és més gran. Per això, és vital comptar amb algun mecanisme de tolerància a fallades en les xarxes d'interconnexió per als gran supercomputadors actuals. En altres paraules, és d'esperar bona relació cost-prestacions amb una alta tolerància a fallades. Aquesta tesi té dos objectius principals. El primer objectiu combina les avantatges de les topologies directes i indirectes per a crear una nova família de topologies amb el millor dels dos mons. En concret, ens centrem en el disseny de una nova família de topologies capaç d'interconnectar una gran quantitat de nodes sent capaç d'obtenir molt bones prestacions amb un baix cost hardware. La família de topologies proposada, que hem nomenat k-ary n-direct s-indirect, té una estructura n-dimensional, on els diferents k nodes d'una dimensió se connecten entre si mitjançant una petita topologia indirecta amb s etapes. També dissenyarem un algoritme d'encaminament determinista i un altre adaptatiu per a la família de topologies proposta. Finalment, ens centrarem en estudiar la tolerància a fallades per a la família de topologies proposada. Per a això s'estudiaran els mecanismes de tolerància a fallades existents en topologies similars i es dissenyarà un mecanisme capaç d'aprofitar al màxim les característiques d'aquesta nova família. El segon objectiu consisteix en la creació d'algoritmes d'encaminament capaços d'evitar el perniciós efecte Head-of-line blocking que pot créixer ràpidament amb un gran número de nodes de computació. Per a evitar aquest efecte es dissenyaran algoritmes d'encaminament capaços de classificar de forma eficient els paquets en els diferents canals virtuals disponibles, evitant així que l'aparició d'un punt calent ( / Peñaranda Cebrián, R. (2017). Improvement of interconnection networks for clusters: direct-indirect hybrid topology and HoL-blocking reduction routing [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/79550 / TESIS
67

Metal oxide nanocrystalline thin films as buffer layers in organic/ hybrid solar cells

Bowers, Norman Mark January 2019 (has links)
>Magister Scientiae - MSc / Without reverting to encapsulation, organic bulk - heterojunction solar cells can be protected from the oxidation of the highly reactive low work function cathode metal electrode, by the deposition of metal oxide buffer layers onto an indium-tin oxide (ITO) substrate. The zinc-oxide (ZnO) or titanium dioxide (TiO2) layer can serve as an electron collecting contact. In such a case the ordering of layer deposition is inverted from the traditional layer sequencing, using an additional effect of the metal oxide layer acting as a hole blocking contact
68

Atmosférické blokování a jeho klimatologie v závislosti na použitých kritériích detekce / Atmospheric blocking and its climatology with respect to used detection criteria

Dragula, Adam January 2021 (has links)
Atmospheric blocking is a synoptic-scale weather phenomenom, which might have significant economic and social impacts on account of a correlation with severe weather features, such as heat waves, persistent drought periods or floods. Several objective detection methods were developed in order to study blocking events. These methods are described and qualitatively discussed in the review part of the thesis. Chosen detection methods were subsequently used for an analysis of basic blocking characteristics over European region. Time evolution of blocking frequency and blocking duration is the key part of results, focusing on possible correlation of these characteristics with the global temperature rise within climate change.
69

Essays on Intellectual Property Rights Protection and Economic Growth / 知的財産権保護と経済成長に関する研究)

Niwa, Sumiko 26 March 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(経済学) / 甲第20875号 / 経博第570号 / 新制||経||284(附属図書館) / 京都大学大学院経済学研究科経済学専攻 / (主査)教授 柴田 章久, 教授 矢野 誠, 准教授 遊喜 一洋 / 学位規則第4条第1項該当 / Doctor of Economics / Kyoto University / DGAM
70

How will the Stimulus Similarity Influence the Effects of the Presentation Types on Learning and Retention?

Zhao, Wanting 04 August 2020 (has links)
No description available.

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