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ON SIMPLE BUT HARD RANDOM INSTANCES OF PROPOSITIONAL THEORIES AND LOGIC PROGRAMSNamasivayam, Gayathri 01 January 2011 (has links)
In the last decade, Answer Set Programming (ASP) and Satisfiability (SAT) have been used to solve combinatorial search problems and practical applications in which they arise. In each of these formalisms, a tool called a solver is used to solve problems. A solver takes as input a specification of the problem – a logic program in the case of ASP, and a CNF theory for SAT – and produces as output a solution to the problem. Designing fast solvers is important for the success of this general-purpose approach to solving search problems. Classes of instances that pose challenges to solvers can help in this task.
In this dissertation we create challenging yet simple benchmarks for existing solvers in ASP and SAT.We do so by providing models of simple logic programs as well as models of simple CNF theories. We then randomly generate logic programs as well as CNF theories from these models. Our experimental results show that computing answer sets of random logic programs as well as models of random CNF theories with carefully chosen parameters is hard for existing solvers.
We generate random logic programs with 2-literals, and our experiments show that it is hard for ASP solvers to obtain answer sets of purely negative and constraint-free programs, indicating the importance of these programs in the development of ASP solvers. An easy-hard-easy pattern emerges as we compute the average number of choice points generated by ASP solvers on randomly generated 2-literal programs with an increasing number of rules. We provide an explanation for the emergence of this pattern in these programs. We also theoretically study the probability of existence of an answer set for sparse and dense 2-literal programs.
We consider simple classes of mixed Horn formulas with purely positive 2- literal clauses and purely negated Horn clauses. First we consider a class of mixed Horn formulas wherein each formula has m 2-literal clauses and k-literal negated Horn clauses. We show that formulas that are generated from the phase transition region of this class are hard for complete SAT solvers. The second class of Mixed Horn Formulas we consider are obtained from completion of a certain class of random logic programs. We show the appearance of an easy-hard-easy pattern as we generate formulas from this class with increasing numbers of clauses, and that the formulas generated in the hard region can be used as benchmarks for testing incomplete SAT solvers.
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The Regulation of Neuronal Excitability and Nociception by Tonic GABAergic InhibitionBonin, Robert 23 July 2013 (has links)
The mammalian central nervous system maintains a delicate balance between neuronal excitation and inhibition. Conventional synaptic inhibition is mediated through the transient activity of postsynaptic γ-aminobutyric acid (GABA) at type A GABA (GABAA) receptors. A subset of GABAA receptors is also located outside of inhibitory synapses. These extrasynaptic receptors generate a tonic inhibitory conductance in response to low concentrations of extracellular GABA. Tonic inhibition broadly suppresses neuronal activity and regulates many vital processes such as sleep, consciousness and memory formation.
This thesis examines the physiological effects of tonic inhibition at the cellular level and in the behaving animal. This thesis also explores whether gabapentin, a commonly used sedative, anxiolytic, and analgesic drug, enhances tonic GABAergic inhibition. I hypothesize that: (1) tonic GABAA receptor activity reduces the intrinsic excitability of neurons; (2) the activity of tonically active GABAA receptors in spinal pain pathways attenuates nociception; and (3) tonic inhibition can be upregulated by gabapentin.
The results show that a tonic inhibitory current generated by α5 subunit-containing GABAA (α5GABAA) receptors reduces the excitability of hippocampal pyramidal neurons excitability by increasing the rheobase, but does not change the gain of action potential firing. A similar shunting inhibition is present in spinal cord lamina II neurons that is generated by δ subunit-containing GABAA receptors. The activity of these receptors in spinal nociceptive pathways reduces acute thermal nociception and may constrain central sensitization in a behavioural model of persistent pain. Finally, gabapentin increases a tonic inhibitory current in cultured hippocampal neurons independent from changes in the expression of α5GABAA receptors or in the concentration of GABAA receptor ligands.
The results of this thesis demonstrate that tonically active GABAA receptors play an important role in the regulation of neuronal activity and nociception, and that tonic inhibition represents a novel target of therapeutic drugs.
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Optimierung der Hupkraftverteilung eines airbagintegrierten Automobillenkrades mit Hilfe einer Parameterstudie / Horn force optimization of a airbag integrated automotive steering wheel with a parameter analysisPietsch, Karsten 12 May 2011 (has links) (PDF)
Die Hupkraftverteilung eines airbagintegrierten Automobillenkrades wird mit Hilfe einer Parameterstudie in MathCAD so optimiert, das an jeder Krafteinleitungsposition die Hupe mit einer geforderten Mindestkraft betätigt werden kann.
Nach der Modellierung in MathCAD der zugehörigen Geometrie und der Dimensionierung der Federlagerung ist das zugehörige mechanische Ersatzmodell mit Hilfe einer Parameterstudie verändert worden, so dass die Hupkraftforderung erfüllt wird.
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Evidence of Reopened Microfractures in Production Data of Hydraulically Fractured Shale Gas WellsApiwathanasorn, Sippakorn 2012 August 1900 (has links)
Frequently a discrepancy is found between the stimulated shale volume (SSV) estimated from production data and the SSV expected from injected water and proppant volume. One possible explanation is the presence of a fracture network, often termed fracture complexity, that may have been opened or reopened during the hydraulic fracturing operation.
The main objective of this work is to investigate the role of fracture complexity in resolving the apparent SSV discrepancy and to illustrate whether the presence of reopened natural fracture network can be observed in pressure and production data of shale gas wells producing from two shale formations with different well and reservoir properties.
Homogeneous, dual porosity and triple porosity models are investigated. Sensitivity runs based on typical parameters of the Barnett and the Horn River shale are performed. Then the field data from the two shales are matched.
Homogeneous models for the two shale formations indicate effective infinite conductivity fractures in the Barnett well and only moderate conductivity fractures in the Horn River shale. Dual porosity models can support effectively infinite conductivity fractures in both shale formations.
Dual porosity models indicate that the behavior of the Barnett and Horn River shale formations are different. Even though both shales exhibit apparent bilinear flow behavior the flow behaviors during this trend are different. Evidence of this difference comes from comparing the storativity ratio observed in each case to the storativity ratio estimated from injected fluid volumes during hydraulic fracturing. In the Barnett shale case similar storativity ratios suggest fracture complexity can account for the dual porosity behavior. In the Horn River case, the model based storativity ratio is too large to represent only fluids from hydraulic fracturing and suggests presence of existing shale formation microfractures.
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The Calvary C.A.R.E. Group Ministry an expression of meta-church theory in psychological support groups /Clayton, Kevin Wayne. January 1993 (has links)
Thesis (D. Min.)--Mid-America Baptist Theological Seminary, 1993. / Includes bibliographical references (leaves 212-219).
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Changes in the spinal cord and peripheral innervation in an animal model of arthritisAlmarestani, Lina M. G. January 1900 (has links)
Thesis (Ph.D.). / Written for the Dept. of Pharmacology and Therapeutics. Title from title page of PDF (viewed 2009/06/05). Includes bibliographical references.
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The politics of urban regeneration the case of the Golden Horn, Istanbul /Bezmez, Dikmen. January 2008 (has links)
Thesis (Ph. D.)--State University of New York at Binghamton, Department of Sociology, 2008. / Includes bibliographical references.
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O ensino de trompa: um estudo dos materiais didáticos utilizados no processo de formação do trompistaFeitosa, Radegundis Aranha Tavares 15 March 2013 (has links)
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Previous issue date: 2013-03-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Research on instrumental teaching have gone through significant development in recent
decades, gaining, as a result, considerable importance and legitimacy, especially within the
context of research in music education. Based on this fact, the present work shows the results
of a study on instrumental teaching, contemplating most specifically the teaching of the
French horn in northeastern Brazil. Thus, the research involves horn teachers working in the
Federal University of Paraíba, Federal University of Pernambuco, Federal University of Bahia
and Federal University of Rio Grande do Norte. This dissertation aims at presenting and
analyzing the didactic materials employed by these teachers, reflecting on the main features of
such materials, their uses and applications towards the formation of horn players. The
research methodology included bibliographical studies, documental research, semi-structured
interviews and the empirical experiences consolidated by the author s expertise both as a
performer and a teacher of the instrument at Federal University of Rio Grande do Norte and in
other parts of Brazil. One can easily see from the survey that the main didactic material used
was of European origin, focusing on the European orchestral repertoire and the soloist horn
repertoire. However, teachers use this material, adapting it to their pedagogical purposes,
combining it with Brazilian music. The study demonstrates that teachers have adopted it to
their own guidelines, organizing the material and adapting it in accordance with the
professional profiles and realities of both teachers and students. / Os estudos sobre ensino de instrumento têm se expandido significativamente nas últimas
décadas, ganhando espaço e legitimidade, sobretudo no âmbito das pesquisas em educação
musical. Considerando essa realidade, esta dissertação apresenta resultados de uma pesquisa
acerca do ensino instrumental, contemplando mais especificamente o ensino de trompa no
Nordeste brasileiro. Assim, o universo da pesquisa foi constituído pelos professores de trompa
atuantes na Universidade Federal da Paraíba, Universidade Federal de Pernambuco,
Universidade Federal da Bahia e Universidade Federal do Rio Grande do Norte. A dissertação
tem como objetivo geral apresentar e analisar os materiais didáticos que vem sendo utilizados
pelo professores de trompa na Região, refletindo sobre as características desses materiais,
seus usos e possibilidades de aplicação no processo de formação do trompista. A metodologia
da pesquisa abrangeu estudos bibliográficos, pesquisa documental, entrevistas
semiestruturadas, bem como experiências empíricas consolidadas a partir da atuação do autor
como trompista e professor do instrumento na Universidade Federal do Rio Grande do Norte
e em outras localidades do país. A partir da pesquisa realizada ficou evidente que os
principais materiais didáticos utilizados são de origem europeia e focam o repertório
orquestral europeu e o repertório para trompa solista. Apesar disso, os professores utilizam
estes materiais adequando-os a suas propostas pedagógicas, inserindo cada vez mais o
trabalho com a música brasileira. O trabalho demonstrou que cada professor possui
direcionamentos próprios, organizando os materiais que utilizam, principalmente, em função
da realidade da trajetória profissional de cada um e do perfil dos estudantes de cada contexto
de ensino.
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Concerto for Two Horns in E-flat Major Attributed to Joseph Haydn: A New Arrangement for Wind EnsembleJanuary 2011 (has links)
abstract: A new arrangement of the Concerto for Two Horns in E-flat Major, Hob. VIId/6, attributed by some to Franz Joseph Haydn, is presented here. The arrangement reduces the orchestral portion to ten wind instruments, specifically a double wind quintet, to facilitate performance of the work. A full score and a complete set of parts are included. In support of this new arrangement, a discussion of the early treatment of horns in pairs and the subsequent development of the double horn concerto in the eighteenth century provides historical context for the Concerto for Two Horns in E-flat major. A summary of the controversy concerning the identity of the composer of this concerto is followed by a description of the content and structure of each of its three movements. Some comments on the procedures of the arrangement complete the background information. / Dissertation/Thesis / D.M.A. Music 2011
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Přehled obchodu s exempláři nosorožců / Overview of the trade in specimens of rhinocerosJEŽKOVÁ, Věra January 2015 (has links)
The subject of this thesis was focused on the analysis of international trade with selected specimens of rhino species (trophies, horns, live rhinos, carvings, horn carvings, derivatives) in 2004 - 2013. The trade at the European Union, taking into accounts the position of the Czech Republic, and the global worldwide trade were evaluated in term of importer and exporter and source, purpose and origin of specimens. Evaluation was based on data from the Cites Trade Database which was further processed via contingency tables and graphs. It was found that there was a decrease of import and export in 2013. The most imported specimens were live rhinos in the world (40,5%) and trophies in the European Union, the most exported specimens were trophies in the world (39,4%) and carvings (80,7%) in the European Union. The largest importer was USA in the world (16,6%) and Spain in the European Union (3%). The largest exporter in the world was South Africa (73,9%) and United Kingdom in the European Union (4,6%). The Czech Republic was imported 0,8% of total import and exported 0,2% of total export. Imported specimens came mostly from the wild (62,1%), the country of origin was not completed and were imported mainly as hunting trophies (33,4%). Exported specimens came mostly from the wild (76,3%), the country of origin was not completed (82,2%) and were exported primarily as hunting trophies The results indicate an overall downward trend in the legal trade but also confirm the considerable interest in horns in Asia. Therefore, it is necessary to continue to monitor all transactions.
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