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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.
581

PPP em tempo real com estimativa das correções dos relógios dos satélites no contexto de rede GNSS

Marques, Haroldo Antonio [UNESP] 26 April 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:30:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-04-26Bitstream added on 2014-06-13T20:40:33Z : No. of bitstreams: 1 marques_ha_dr_prud.pdf: 2254240 bytes, checksum: 4a444b57aeb7b0a9588734345c28c149 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dentre os diversos métodos possíveis de posicionamento GNSS, encontra-se atualmente em evidência aqueles que proporcionam posicionamento em tempo real (ou próximo do tempo real) com acurácia ao nível centimétrico ou decimétrico. Nesse caso, destaca-se o PPP em tempo real, o qual requer a disponibilização de órbitas precisas em tempo real, bem como as correções ou erros dos relógios dos satélites. Atualmente, é possível utilizar as efemérides preditas denominadas IGU, as quais são disponibilizadas pelo IGS, porém, as correções dos relógios dos satélites contidas nessas efemérides não apresentam acurácia suficiente (3 ns @ 0,9 m) para obtenção de resultados com qualidade centimétrica no PPP. Logo, é necessário pesquisar e desenvolver metodologias adequadas para estimar as correções dos relógios dos satélites com melhor qualidade para aplicação no PPP em tempo real. A estimativa das correções dos relógios dos satélites pode ser realizada com base numa rede de estações GNSS de referência. Nesta tese, a metodologia adotada para estimar estas correções consiste em realizar o ajustamento dos dados no modo PPP para uma rede de estações GNSS. Dessa forma, todos os efeitos sistemáticos envolvidos com os sinais dos satélites GNSS devem ser modelados adequadamente para cada estação da rede, realizando-se assim a estratégia denominada de PPP em rede. Uma vez estimadas as correções dos relógios dos satélites em tempo real, estas devem ser enviadas ao usuário, o qual as utilizará para aplicação... / Among several possible methods of GNSS positioning, it is currently in evidence those that provide real time positioning (or near real time) with accuracy near to decimeter or centimeter level. In this case, we highlight the real time PPP method, which requires the availability of real time precise orbits and corrections or errors of the satellites clocks. Currently, it is possible to use the predicted IGU ephemerides which are made available by the IGS centers. However, the satellites clocks corrections available in the IGU do not present enough accuracy (3 ns @ 0.9 m) to accomplish real time PPP with the level of centimeter accuracy. Therefore, it is necessary to research and develop appropriate methodologies for estimating the satellite clock corrections in real time with better quality for real time PPP aplication. The estimation of satellite clock corrections can be performed based on a GNSS network of reference. In this PhD thesis, the methodology used to estimate these corrections is based on the adjustment of data in the PPP mode for stations of a GNSS network. Thus, all systematic effects involved with the GNSS satellite signals must... (Complete abstract click electronic access below)
582

Improving web accessibility for colour vision deficiency (CVD) users : A response time study / Förbättrad webbtillgänglighet för användare med defekt färgseende : En studie med mätning i responstid

Edmark, Gunillah January 2018 (has links)
The digital world is acquiring more space in today’s society. With this being said, it is important to keep the web content interpretable for everyone, despite any kind of disability. This study focuses on colour vision deficiency and how to implement a real-time colour correction instantly in the web browser, without any additional assistive technologies needed. Two almost identical webpages have been developed for this project, with the difference being that one is with a colour correction function and one without, who then are measured in page-loading time to see if there is any greater loss of performance when executing the colour conversion.
583

Caring More About EQ Than IQ : Automatic Equalizing of Audio Signals

Axelson-Fisk, Magnus January 2018 (has links)
In this bachelor thesis, the possiblity to correct for room acousticsbased on frequency analysis is studied. A software to calculate transferfunctions online was constructed and tested. This was done using a ver-sion of the Maximum Length Sequence method, which is a method thatrequires long sequences for rooms with long reverberation. During theproject, it was noted that zero padding the sequences improved the ac-curacy greatly, it was also noted that the length of the zero pad aectedthe results. The software was tested both in computer simulations andin practice. While testing in practice, it was noted that the system haslimitations on which rooms it would work in. All testsignals were recordedand afterwards, compared to the original recording. The constructed soft-ware showed, that it is possible to correct for unknown transfer functionsusing only frequency analysis, to some extent. Further, it does correct forthe room's transfer function, but it is dicult to say if it this is valid forall rooms and transfer functions.
584

Oprava nevalidních stromů vůči regulárním stromovým gramatikám / Correction of Invalid Trees with Respect to Regular Tree Grammars

Svoboda, Martin January 2015 (has links)
XML documents and related technologies represent one of the most widespread ways how data on the Web are maintained and interchanged. Unfortunately, many of the real-world documents contain various types of consistency issues that prevent their successful automated processing. In this thesis we focus on the problem of the structural invalidity and its correction. In particular, having one potentially invalid XML document modeled as a tree, and a schema in DTD or XML Schema languages modeled as a regular tree grammar, our goal is to find all the minimal corrections of this tree. The model we proposed builds on top of the recursively nested structures of correction multigraphs, where the shortest paths are being found. For this purpose we formally introduce three correction strategies with different pruning optimizations applied. According to the experiments we performed, the refinement correction strategy not only significantly outperforms all the other existing approaches, but also guarantees important characteristics the others cannot. Powered by TCPDF (www.tcpdf.org)
585

Bayesian stochastic blockmodels for community detection in networks and community-structured covariance selection

Peng, Lijun 08 April 2016 (has links)
Networks have been widely used to describe interactions among objects in diverse fields. Given the interest in explaining a network by its structure, much attention has been drawn to finding clusters of nodes with dense connections within clusters but sparse connections between clusters. Such clusters are called communities, and identifying such clusters is known as community detection. Here, to perform community detection, I focus on stochastic blockmodels (SBM), a class of statistically-based generative models. I present a flexible SBM that represents different types of data as well as node attributes under a Bayesian framework. The proposed models explicitly capture community behavior by guaranteeing that connections are denser within communities than between communities. First, I present a degree-corrected SBM based on a logistic regression formulation to model binary networks. To fit the model, I obtain posterior samples via Gibbs sampling based on Polya-Gamma latent variables. I conduct inference based on a novel, canonically mapped centroid estimator that formally addresses label non-identifiability and captures representative community assignments. Next, to accommodate large-scale datasets, I further extend the degree-corrected SBM to a broader family of generalized linear models with group correction terms. To conduct exact inference efficiently, I develop an iteratively-reweighted least squares procedure that implicitly updates sufficient statistics on the network to obtain maximum a posteriori (MAP) estimators. I demonstrate the proposed model and estimation on simulated benchmark networks and various real-world datasets. Finally, I develop a Bayesian SBM for community-structured covariance selection. Here, I assume that the data at each node are Gaussian and a latent network where two nodes are not connected if their observations are conditionally independent given observations of other nodes. Under the context of biological and social applications, I expect that this latent network shows a block dependency structure that represents community behavior. Thus, to identify the latent network and detect communities, I propose a hierarchical prior in two levels: a spike-and-slab prior on off-diagonal entries of the concentration matrix for variable selection and a degree-corrected SBM to capture community behavior. I develop an efficient routine based on ridge regularization and MAP estimation to conduct inference.
586

Méthodologie d'évaluation des impacts cliniques et dosimétriques d'un changement de procédure en radiothérapie : Aspect - Radio physique et médical / Methodology to assess the clinical and dosimetric impacts resulting from the change of a calculation algorithm in radiotherapy : Radiological Medical Physics

Chaikh, Abdulhamid 13 March 2012 (has links)
Introduction et objectif : La prescription des traitements en radiothérapie est basée sur l'analyse de la répartition de dose calculée par le TPS. Un changement d'algorithme de calcul doit être précédé d'une analyse dosimétrique complète, afin que les impacts cliniques soient maitrisés. Nous présentons une méthodologie de mise en œuvre d'un nouveau TPS. Matériel et méthodologie : Nous avons utilisé 5 algorithmes de calcul de dose. Nous avons comparé 6 plans de traitement avec des configurations identiques : patient, énergie, balistique. Nous avons comparé 12 localisations tumorales : 5 poumons, 1 œsophage, 1 sein, 3 ORL, 1 encéphales et 1 prostate. Le principe de méthodologie est basé sur deux critères d'analyse : 1.Critère d'analyse dosimétrique : nous avons classé les outils d'analyse en 3 catégories : analyse liée à la dose de traitement, analyse liée à la distribution de dose et analyse liée à la répartition de la dose 2.Critère d'analyse statistique : nous avons considéré que nous avons 5 séries de mesure liée à 5 algorithmes. Nous avons considéré les valeurs dosimétriques calculées par l'ancien algorithme comme valeurs de référence. Le test de comparaison statistique utilisé était un Wilcoxon pour série apparié avec un seuil de signification de 5% et un intervalle de confiance à 95%. Résultats et discussion : Nous avons trouvé des écarts pour tous les paramètres comparés dans cette étude. Ces écarts dépendent de la localisation de la tumeur et de l'algorithme de calcul. La maîtrise statistique des résultats nous permet, d'une part de diagnostiquer et interpréter les écarts dosimétriques observés et d'autre part, de déterminer si les écarts sont significatifs. Conclusion : Nous proposons une méthodologie qui permet de quantifier d'éventuels écarts dosimétriques lors d'un changement d'algorithme. L'analyse statistique permet de s'assurer que les résultats sont significatifs. / Background and purpose The validation of a treatment plan is based on the analysis of dose distributions. The dose distributions are calculated by algorithms implanted in TPS. So, the changing of an algorithm must be preceded by a complete dosimetric analysis in order to provide a method for controlling the clinical impact of this change. We present in this study the methodology used for implementing a new TPS in our clinic. Materials and methods We used five algorithms for dose calculation: Clarkson, PBC, Batho Power Law, modified Batho and EqTAR. We compared six treatment plans with identical configurations: 2 plans without heterogeneity correction and 4 with density correction. We have compared nine tumours locations: 5 lungs, 1 oesophagus, 1 breast, 3head and neck, 1 brain and 1 prostate. We compared the following parameters: monitors units, HDV, isodoses, covering index, index of homogeneity, conformity index, geometric index and gamma index for 2D and 3D. We analyzed the results using a statistical evaluation and the method plot box. Results and discussion The gamma index 3D and histogram gamma generated for a CT slice can be used to compare various algorithms and radiotherapy plans. We found a difference in all parameters compared when the algorithm is changed. For example, we found a 5% difference in monitors units and 7% in dose for the pulmonary cancer case, when we change from PBC to EqTAR .This may leads to an increased of 30% in the complication rate. The statistical evaluation serves as a rapid interpretation and diagnostic of dosimetric differences and allows the determination of the significance of these differences. Conclusion We proposed a methodology that allows the quantification of dosimetric variation during the change of calculation algorithm in radiotherapy. This methodology provides a valuable technique for quantitative comparison of various algorithms and radiotherapy plans
587

Classes de correção de fluxo e resolução de problemas : o olhar dos alunos, professores e assistente técnico pedagógico /

Buranello, Luciana Vanessa de Almeida. January 2007 (has links)
Orientador: Nelson Antonio Pirola / Banca: Dione Lucchesi de Carvalho / Banca: Rita Melissa Lepre / Resumo: O objetivo do presente estudo foi investigar as contribuições que as classes de Correção de Fluxo proporcionaram aos alunos em termos de solução de problemas matemáticos, sob a visão de alunos, professores e ATP. Para tanto foram investigados: alunos egressos das classes de Correção de Fluxo, alunos que freqüentaram apenas classes regulares, professoras que lecionaram no projeto em questão e que hoje trabalham com os alunos egressos e o assistente técnico pedagógico que realizou as capacitações durante o desenvolvimento do projeto. Trata-se de uma amostra por conveniência. Foi possível constatar através de uma análise fenomenológica que o Projeto Correção de Fluxo não conseguiu atingir seus objetivos, ou seja, não promoveu a inclusão dos alunos que dele fizeram parte, pois os mesmos não resolvem problemas básicos envolvendo os números inteiros. Foi possível verificar que a exclusão destes alunos apenas foi adiada na instituição escolar investigada. Tais resultados apontam para a necessidade de melhorias em termos de políticas públicas educacionais, assim como de suas medidas operacionais. / Abstract: The objetive of the present study was investigate the contributions that the classes of Correction of Flow provided to the students in terns of solution of mathematical problems, under the student's vision, teacher and TPA. For so much whe investigated: regressor students of the classes of "Flow Correction", students that just frequented regular classes, teachers that taught in the project in subject and that today work with the egressor students and the pedagogia technical assistant that realized the trainings during the development of the project. It is a sample for convenience. It was possibible to verify through a fenomenologic analysis that the project "Flow correction" didn't get to reach its objectives, that is to say, it didn't promote the student's inclusion that took past of its, because the same ones don't solve basic problems, involving the whole numbers. It was possible to verify that these student's exclusion was just postponed in the investigated school institution. Such results point for the need of improvements in tenns of educational public politics, as wele as for their operational measures. / Mestre
588

Investindo no conflito : a correção pelo outro construindo discordâncias agravadas

Loder, Letícia Ludwig January 2006 (has links)
O presente trabalho tem por objeto de análise seqüências de discordância levadas adiante por correções pelo outro, e seu objetivo é caracterizar a ocorrência de correções pelo outro, sublinhando suas implicações e distinções em relação a outros recursos para discordar. Seguindo a tradição de pesquisa em Análise da Conversa, em que a relação entre correção e discordância tem sido apontada mas não elucidada por completo, cerca de oito horas de registros audiovisuais de interações cotidianas foram geradas, e, nesse corpus, localizadas e reunidas instâncias em que a correção pelo outro levava adiante uma discordância entre os interlocutores. Observou-se que, ocorrendo no início, no meio ou no fim de uma discordância, a correção produz não apenas um questionamento de um item/expressão equivocado no turno do interlocutor, mas centralmente implica o questionamento da apresentação do interlocutor como conhecedor do tópico em debate. Observou-se, ainda, a redução de índices de despreferência por discordância ao longo da seqüência, evidenciando a orientação dos participantes para acentuar progressivamente o debate. Comparando-se com outros recursos para discordar, observou-se que a correção pelo outro intervém mais diretamente no turno do opositor, implica necessariamente anulação da proposta do opositor, permite um monitoramento do ponto em que a discordância foi abandonada (quando é o caso) e, ao implicar a legitimidade do falante sobre o tópico em debate, implica necessariamente a falta de autoridade do interlocutor. Conclui-se, portanto, que a correção pelo outro é um recurso bastante mais agravado do que outros para produzir discordâncias, evidenciando, nas seqüências em que ocorre, a orientação dos participantes para sublinhar a oposição, em lugar de mitigá-la. / This study is aimed at characterizing the occurrence of other-correction in disagreement sequences by focusing on its implication to the sequence and its particularities in relation to other methods for disagreeing. Based on the framework of Conversation Analysis, within which the relationship between other-correction and disagreement has been pointed out, though not yet accounted for in detailed analysis, roughly eight hours of daily interaction were recorded, and instances of other-correction in disagreement sequences were identified. Othercorrections were observed to be implicated in the beginning, middle or end of disagreement sequences, focusing not only on trouble in an item/expression in previous turn, but implying crucially the questioning of the presentation of previous speaker as knowledgeable about the topic. The orientation to preference for disagreement as the sequence progressed was also observed, evidencing participants’ orientation to aggravate the dispute. In comparison to other methods for disagreeing, other-correction was observed to be more directly opposed to previous turn, to imply the opponent’s position as necessarily invalid, to allow the monitoring of moves to abort the sequence (when this is the case), and to necessarily impute lack of authority on the topic to the interlocutor. Other-correction is concluded to be a method engendering much more aggravation than other methods for disagreeing, evidencing the orientation of participants to invest in, rather than mitigate, the opposition.
589

An empirical analysis of the relationship between food inflation and passenger vehicle purchases in South Africa

Tshiakambila, Eric Kateta 02 1900 (has links)
Food inflation in South Africa has been viewed as an important source of underlying inflationary pressures in the economy due to its persistence beyond that of other commodities. Although several studies found food to be one of the factors that influence purchase decisions, there still appears to be an absence of research that directly links food inflation to consumers’ decisions, especially when financing the purchase of new passenger vehicles in South Africa. In this regard, this study investigated whether the increase in the prices of food products has a significant effect on passenger vehicle purchases in South Africa. Leaning on the literature that argues that economic factors do not play much of a role in passenger vehicle purchase decisions in South Africa, it was hypothesised that there is no supported relationship between food inflation and passenger vehicle purchases in South Africa. Using secondary time series data, the Pearson correlation test revealed a negative but insignificant relationship between food inflation and vehicle purchases in South Africa. The ordinary least squares estimate of the purchase function, taking into account several economic factors that influence passenger vehicle purchase decisions in the literature, showed that disposable income of households along with vehicle purchases of the previous period are to be considered as main determinants of vehicle purchases in South Africa. In addition, it was also revealed that new vehicle prices are also a significant determinant of vehicle purchases. The Johansen cointegration test revealed that the variables in the vehicle purchase function were cointegrated in the long run. The vector error correction model showed a long-run relationship, albeit insignificant, between food inflation and vehicle purchases and no relationship between the two variables in the short run. The Granger causality test revealed that food inflation and vehicle purchases are independent from each other, meaning that no causal effect was found between the variables, regardless of the direction of the test. This study concluded that economic factors such as interest rate and fuel price have an insignificant influence on passenger vehicle purchases in South Africa. In the same line, the impact of food inflation on passenger vehicle purchases in South Africa was found to be insignificant, therefore, the conclusion was drawn that the increase in the prices of food products will not play a considerable role in consumers’ decisions regarding passenger vehicle purchase in South Africa. / Business Management / M. Com. (Business Management)
590

Hodnocení transfekce nukleových kyselin v in vitro podmínkách. / IN VITRO assays for investigating nucleic acid delivery.

Mihaličoková, Dajana January 2018 (has links)
Charles University, Faculty of Pharmacy in Hradec Králové, Department of Biochemical Sciences University of Vienna, Faculty center for Pharmacy, Department of Pharmaceutical Chemistry, Laboratory of MacroMolecular Cancer Therapeutics Candidate: Dajana Mihaličoková Supervisor (Charles University): PharmDr. Anna Jirkovská, Ph.D. Supervisor (University of Vienna): Univ.Prof. Dipl. Ing. Dr. Manfred Ogris Co-supervisor (University of Vienna): Dr. Haider Sami, Ph.D. Title of diploma thesis: In vitro assays for investigating nucleic acid assay Keywords: transfection, splice correction, BCA assay, polyplexes One of the most important tasks of biochemical research is to find out the right way how to cure cancer, genetic disorders and other illnesses which are still not curable. Towards this, gene therapy is emerging as a potential treatment owing to its ability to deliver genetic material inside the cell. Reporer gene based transfection process can be used to study gene expression. Transfection is mediated by vectors, either of viral or non-viral origin. Non-viral vectors offer several advantages over the viral counterparts like easier to synthesize, relatively cheap and the most important is their non-immunogenicity. Cationic polymers based on polyethylenimine form complexes with plasmid DNA reffered to as...

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