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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.
101

Oscilace mechanických systémů s implicitními konstitutivními vztahy / Oscillations in mechanical systems with implicit constitutive relations.

Babováková, Jana January 2012 (has links)
We study a system of differential-algebraic equations, describing motions of a mass-spring-dashpot oscillator by three different forms of implicit constitu- tive relations. For some problems with fully implicit but linear constitutive laws for combined force, we find conditions for solution stability. Assuming monotone relationship between the displacement, velocity and the respective forces, we prove global existence of the solutions. For a linear spring and a dashpot with maximal monotone relationship between the damping force and the velocity, we prove the global existence and uniqueness result. We also solve this problem numerically for Coulomb-like damping term.
102

Scalable System-Wide Traffic Flow Predictions Using Graph Partitioning and Recurrent Neural Networks

Reginbald Ivarsson, Jón January 2018 (has links)
Traffic flow predictions are an important part of an Intelligent Transportation System as the ability to forecast accurately the traffic conditions in a transportation system allows for proactive rather than reactive traffic control. Providing accurate real-time traffic predictions is a challenging problem because of the nonlinear and stochastic features of traffic flow. An increasingly widespread deployment of traffic sensors in a growing transportation system produces greater volume of traffic flow data. This results in problems concerning fast, reliable and scalable traffic predictions.The thesis explores the feasibility of increasing the scalability of real-time traffic predictions by partitioning the transportation system into smaller subsections. This is done by using data collected by Trafikverket from traffic sensors in Stockholm and Gothenburg to construct a traffic sensor graph of the transportation system. In addition, three graph partitioning algorithms are designed to divide the traffic sensor graph according to vehicle travel time. Finally, the produced transportation system partitions are used to train multi-layered long shortterm memory recurrent neural networks for traffic density predictions. Four different types of models are produced and evaluated based on root mean squared error, training time and prediction time, i.e. transportation system model, partitioned transportation models, single sensor models, and overlapping partition models.Results of the thesis show that partitioning a transportation system is a viable solution to produce traffic prediction models as the average prediction accuracy for each traffic sensor across the different types of prediction models are comparable. This solution tackles scalability issues that are caused by increased deployment of traffic sensors to the transportation system. This is done by reducing the number of traffic sensors each prediction model is responsible for which results in less complex models with less amount of input data. A more decentralized and effective solution can be achieved since the models can be distributed to the edge of the transportation system, i.e. near the physical location of the traffic sensors, reducing prediction and response time of the models. / Prognoser för trafikflödet är en viktig del av ett intelligent transportsystem, eftersom möjligheten att prognostisera exakt trafiken i ett transportsystem möjliggör proaktiv snarare än reaktiv trafikstyrning. Att tillhandahålla noggrann trafikprognosen i realtid är ett utmanande problem på grund av de olinjära och stokastiska egenskaperna hos trafikflödet. En alltmer utbredd använding av trafiksensorer i ett växande transportsystem ger större volym av trafikflödesdata. Detta leder till problem med snabba, pålitliga och skalbara trafikprognoser.Avhandlingen undersöker möjligheten att öka skalbarheten hos realtidsprognoser genom att dela transportsystemet i mindre underavsnitt. Detta görs genom att använda data som samlats in av Trafikverket från trafiksensorer i Stockholm och Göteborg för att konstruera en trafiksensor graf för transportsystemet. Dessutom är tre grafpartitioneringsalgoritmer utformade för att dela upp trafiksensor grafen enligt fordonets körtid. Slutligen används de producerade transportsystempartitionerna för att träna multi-layered long short memory neurala nät för förspänning av trafiktäthet. Fyra olika typer av modeller producerades och utvärderades baserat på rotvärdes kvadratfel, träningstid och prediktionstid, d.v.s. transportsystemmodell, partitionerade transportmodeller, enkla sensormodeller och överlappande partitionsmodeller.Resultat av avhandlingen visar att partitionering av ett transportsystem är en genomförbar lösning för att producera trafikprognosmodeller, eftersom den genomsnittliga prognoser noggrannheten för varje trafiksensor över de olika typerna av prediktionsmodeller är jämförbar. Denna lösning tar itu med skalbarhetsproblem som orsakas av ökad användning av trafiksensorer till transportsystemet. Detta görs genom att minska antal trafiksensorer varje trafikprognosmodell är ansvarig för. Det resulterar i mindre komplexa modeller med mindre mängd inmatningsdata. En mer decentraliserad och effektiv lösning kan uppnås eftersom modellerna kan distribueras till transportsystemets kant, d.v.s. nära trafiksensorns fysiska läge, vilket minskar prognosoch responstid för modellerna.
103

Contribucions a l'estudi dels grafs i digrafs propers als de Moore

Conde Colom, Josep 06 March 2013 (has links)
El principal objectiu d'aquesta tesi és el de contribuir a l'estudi de l'existència i classificació dels grafs i digrafs que puguin admetre el màxim nombre de vèrtexs sota determinades condicions donats el grau i el diàmetre. Aquest estudi consta de tres parts ben diferenciades, una sobre digrafs i dos sobre grafs. En el treball relacionat amb els digrafs demostrem que els digrafs quasi de Moore de diàmetre k = 3 i qualsevol grau no existeixen. Així mateix provem la no existència dels digrafs quasi de Moore de diàmetre 4 i qualsevol grau assumint la irreductibilitat en Q[x] de certs polinomis. En quan als grafs ens hem centrat en l'existència dels de grau d, diàmetre 2 i defecte 2, anomenats (d,2,2)-grafs i assumint la irreductibilitat en Q[x] de certs polinomis provem que no existeixen per a cap grau. A més provem que no existeixen per a graus entre 4 i 50. Finalment estudiem els grafs radials de Moore de grau d i radi k. Proposem diferents mesures per classificar-los d'acord a la proximitat de les seves propietats a les d'un graf de Moore i ordenem segons aquestes mesures tots els grafs radials de Moore en els casos (d,k) = {(3,2), (3,3), (4,2)}. / El principal objetivo de esta tesis es el de contribuir al estudio de la existencia y clasificación de los grafos y digrafos que puedan admitir el máximo número de vértices bajo determinadas condiciones dados el grado y el diámetro. Este estudio consta de tres partes bien diferenciadas, una sobre digrafos y dos sobre grafos. En el trabajo relacionado con los digrafos demostramos que los digrafos casi de Moore de diámetro k = 3 y cualquier grado no existen. Asimismo probamos la no existencia de los digrafos casi de Moore de diámetro 4 y cualquier grado suponiendo la irreducibilidad en Q[x] de ciertos polinomios. En cuanto a los grafos nos hemos centrado en la existencia de los de grado d, diámetro 2 y defecto 2, llamados (d,2,2)-grafos y suponiendo la irreducibilidad en Q[x] de ciertos polinomios probamos que no existen para ningún grado. Además probamos que no existen para grados entre 4 y 50. Finalmente estudiamos los grafos radiales de Moore de grado d y radio k. Proponemos diferentes medidas para clasificarlos de acuerdo a la proximidad de sus propiedades a las de un grafo de Moore y ordenamos según estas medidas todos los grafos radiales de Moore en los casos (d, k) = {(3,2), (3,3), (4,2)}. / The main goal of this thesis is to contribute to the study of the existence and classification of graphs and digraphs that can achieve the maximum number of vertices under certain conditions given the degree and the diameter. This study consists of three differenciated parts, one on digraphs and two on graphs. The work on digraphs focuses on almost Moore digraphs. We prove that they do not exist for diameter 3 and any degree. Besides, we prove the non-existence of almost Moore digraphs of diameter 4 assuming the irreducibility in Q[x] of certain polynomials. Concerning graphs, we discuss the existence of graphs of degree d, diameter 2 and defect 2. Assuming the irreducibility in Q[x] of certain polynomials we prove their non existence. We also show they do not exist for degrees between 4 and 50. Finally we study radial Moore graphs of degree d and radius k. We propose different measures for classifying them in terms of their proximity to extremal properties of a Moore graph. By means of our measures, we are able to enumerate all radial Moore graphs for the cases (d, k) = {(3.2), (3.3), (4.2)}.
104

The influence of the Russian novel on French writers and thinkers with particular reference to Tolstoy and Dostoevsky

Hemmings, Frederick William John January 1949 (has links)
No description available.
105

Reciprocity : where art meets the community : action research in response to artistic encounters and relationships

Filardo, Giuseppe January 2009 (has links)
This practice-led research project examines some of the factors and issues facing artists working in the public domain who wish to engage with the community as audience. Using the methodology of action research, the three major creative projects in this study use art as a socio-political tool with the aim of providing an effective vehicle for broadening awareness, understanding forms of social protest and increasing tolerance for diversity. The three projects: Floodline November 7, 2004, Look in, Look out, and The Urban Terrorist Project, dealt with issues of marginalisation of communities, audiences and graffiti artists respectively. The artist/researcher is outlined as both creator and collaborator in the work. Processes included ephemeral elements, such as temporary installation and performance, as well as interactive elements that encouraged direct audience involvement as part of the work. In addition to the roles of creator and collaborator, both of which included audience as well as artist, the presence of an outside entity was evident. Whether local, legal authorities or prevailing attitudes, outside entities had an unavoidable impact on the processes and outcomes of the work. Each project elicited a range of responses from their respective audiences; however, the overarching concept of reciprocity was seen to be the crucial factor in conception, artistic methods and outcomes.
106

Ramseyovské výsledky pro uspořádané hypergrafy / Ramsey-type results for ordered hypergraphs

Balko, Martin January 2016 (has links)
Ramsey-type results for ordered hypergraphs Martin Balko Abstract We introduce ordered Ramsey numbers, which are an analogue of Ramsey numbers for graphs with a linear ordering on their vertices. We study the growth rate of ordered Ramsey numbers of ordered graphs with respect to the number of vertices. We find ordered match- ings whose ordered Ramsey numbers grow superpolynomially. We show that ordered Ramsey numbers of ordered graphs with bounded degeneracy and interval chromatic number are at most polynomial. We prove that ordered Ramsey numbers are at most polynomial for ordered graphs with bounded bandwidth. We find 3-regular graphs that have superlinear ordered Ramsey numbers, regardless of the ordering. The last two results solve problems of Conlon, Fox, Lee, and Sudakov. We derive the exact formula for ordered Ramsey numbers of mono- tone cycles and use it to obtain the exact formula for geometric Ramsey numbers of cycles that were introduced by Károlyi et al. We refute a conjecture of Peters and Szekeres about a strengthening of the fa- mous Erd˝os-Szekeres conjecture to ordered hypergraphs. We obtain the exact formula for the minimum number of crossings in simple x-monotone drawings of complete graphs and provide a combinatorial characterization of these drawings in terms of colorings of ordered...
107

Kombinatorické otázky v geometrii / Combinatorial problems in geometry

Kynčl, Jan January 2013 (has links)
No description available.
108

Aplikace metod strojového učení na dolování znalosti z dat

Kraus, Jan January 2014 (has links)
The diploma thesis deals with the area of data mining applied to large collections of textual data. Specifically the thesis is focused on sentiment analysis based on the user's subjective verbal assessment in natural language. The first part of the diploma thesis introduces the reader to basic terms of machine learning and data mining applied particularly to large textual data collections. Following is the description of textual data preprocessing methods and principles of machine learning algorithms. In the practical part of this thesis there are experiments designed and subsequently executed using the SPSS Modeler tool. The experimental part is focused especially on identification of significant attributes and recongnition of relationships between them. The emphasis is put especially on thorough interpretation of the results obtained.
109

Características dos doadores de medula óssea e seu impacto no desfecho dos pacientes submetidos a transplante alogênico no Hospital de Clinicas de Porto Alegre

Paz, Alessandra Aparecida January 2015 (has links)
Introdução: O Transplante de Célula Tronco Hematopoiética (TCTH) é um tratamento potencialmente curativo para muitas desordens hematológicas. A disparidade HLA entre doador e receptor é um fator crítico para os resultados do TCTH. No entanto novas evidencias tem demonstrado que outros fatores como a fonte de célula tronco, o tipo de condicionamento e fatores relacionados aos doadores, entre eles o sexo, a idade e o status sorológico para Citomegalovirus (CMV) podem influenciar os desfechos do procedimento. Objetivo: Avaliar as características dos doadores de medula óssea e seu impacto nos desfechos do TCTH em um centro do Sul do Brasil. Métodos: Foram avaliadas retrospectivamente as características dos doadores como sexo, idade, presença de exposição previa ao CMV, incompatibilidade ABO e suas relações com a ocorrência de doença do enxerto contra hospedeiro (DECH) aguda e crônica, a mortalidade relacionada ao transplante (do inglês tumor related mortality – TRM) sobrevida livre de doença (SLD) e sobrevida Global (SG) em todos os pacientes submetidos a TCTH alogênico em um único centro durante o período de 1994 a 2012. Resultados: 347 pacientes foram incluídos na análise. O TCTH aparentado foi significativamente mais freqüente que o não aparentado (81.2 x 18.7), a mediana de idade foi de 34 (1-61) para os receptores e 33 (1-65) para os doadores. Na analise multivariada a presença de DECH agudo (33% vs 47%) p=0,04 e ter doadores mais idosos (>40 anos) foram associados a uma redução de SG em 5 anos (41% vs 52%) p=0,038. Ter um doador acima de 40 anos aumenta significativamente a incidência de DECH aguda (52% vs 65,8%) p=0,03 e crônica (60% vs 43%) p=0,015. O sexo do doador, presença de CMV e incompatibilidade ABO não tiveram influencia nos desfechos. Conclusão: Em um centro único avaliado receber um transplante de CTH de doadores acima de 40 anos aumenta a incidência de DECH aguda e crônica e influencia negativamente na SG. / Background: Hematopoietic Stem cell Transplantation (HSCT) is a curative treatment for many patients with hematological disorders. Donor – recipient genetic disparity, especially involving the HLA systems is a critical factor for HSCT outcome There are increasing evidences, however that other issues as source of stem cell, conditioning regimen, donor gender, age and CMV infection can affect HSCT outcomes. Objective: To study the influence of donor’s characteristics on the HSCT outcomes in a south Brazilian population subjected to allogeneic SCT in a single center. Methods: We retrospectively evaluated donor characteristics such as gender, age, CMV serologic status and ABO compatibility and its relation to the occurrence of acute and chronic graft versus host disease (GVHD), disease free survival (DFS) and overall survival (OS) in all patients submitted to related and unrelated allogeneic HSCT, performed between 1994 and 2012. Results: Overall 347 consecutives HSCT were included in this analysis. Related HSCT was significantly more frequent than unrelated (81.2% x 18.7%); donor and recipient median age were 34 (1- 61) and 33 (1-65), respectively. In the multivariate analyses, presence acute GVHD (33%vs 47%)p=0.04 ,with relative risk and donors older than 40 years old was associated with lower probability of OS in 5 years (41% vs 52%) p=0,038 and higher rate of acute (65.8%vs 52%) p=0.03 and chronic GVHD (43% vs 60%) p=0,015. Donor’s sex, CMV status, ABO incompatibility have not influenced 5-years survival. Conclusions: In a single center population of patients submitted to related and unrelated HSCT in southern Brazil donor older then 40 years of age is a factor negatively influencing HSCT outcome.
110

Sociální sítě a sociální šikana / Social networks and social bullying

KUBÍČEK, Petr January 2014 (has links)
In my thesis I have focused on the issue of social networks and (social) bullying at elementary schools. In the first part of my paper I summarize the theoretical background and provide an overview of findings and opinions published by experts in relation to the issue of bullying and cyber-bullying, while in the second part of my paper I analyze the results of a research performed with the use of an anonymous questionnaire at four (4) elementary schools in the South Bohemia Region (Jihočeský kraj). The schools involved in the research were: two (2) schools with less than 270 pupils in the Prachatice region, one school with more than 270 pupils in the town of Prachatice and one school with more than 270 pupils in the city of České Budějovice. The purpose of the questionnaire investigation was to collect information on the extent in which aggressive behavior and cyber-bullying appear among pupils attending the 5th through 9th grades of the elementary school (age range 11-15). In the final part of the thesis I provide an overview of the results obtained through the research with the use of a BPAQ questionnaire (BussPerry Aggression Questionnaire and aggressive acts).

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