Let V be an n-dimensional vector space over the field of q elements. By a geometric t-[q^n, k, λ] design we mean a collection D of k-dimensional subspaces of V, called blocks, such that every t-dimensional subspace T of V appears in exactly λ blocks in D. A large set, LS [N] [t, k, q^n], of geometric designs is a collection on N disjoint t-[q^n, k, λ] designs that partitions [V K], the collection of k-dimensional subspaces of V. In this work we construct non-isomorphic large sets using methods based on incidence structures known as the Kramer-Mesner matrices. These structures are induced by particular group actions on the collection of subspaces of the vector space V. Subsequently, we discuss and use computational techniques for solving certain linear problems of the form AX = B, where A is a large integral matrix and X is a {0,1} solution. These techniques involve (i) lattice basis-reduction, including variants of the LLL algorithm, and (ii) linear programming. Inspiration came from the 2013 work of Braun, Kohnert, Ostergard, and Wassermann, [17], who produced the first nontrivial large set of geometric designs with t ≥ 2. Bal Khadka and Michael Epstein provided the know-how for using the LLL and linear programming algorithms that we implemented to construct the large sets. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

O presente trabalho versa sobre o controle da atividade do árbitro. Parte-se da premissa de que o papel desempenhado pelo árbitro na condução do processo - denominado atividade do árbitro em contraposição ao resultado dessa atividade: a resposta jurisdicional - está sujeito a desvios. A assunção dessa função pode ser viciada, já que o exercício da arbitragem somente é admitido dentro de determinados limites e condicionado ao consentimento das partes. Da mesma forma, as providências adotadas pelo árbitro no curso do processo podem apresentar inconsistências em relação às disposições legais e contratuais a elas aplicáveis. Diante disso, investiga-se de que forma tais desvios podem ser controlados, estudando-se, para tanto, (i) os órgãos responsáveis por tal controle, (ii) o momento em que tal controle pode ocorrer, (iii) os mecanismos pelos quais tal controle é admitido, e (iv) os vícios na atividade que ensejam controle. / This paper addresses the control of arbitrators role in developing arbitration. It assumes that the role of the arbitrator in developing arbitration what contrasts with the role in deciding the case is subject to irregularities. The assumption of the arbitrators function can be irregular, as arbitration is authorized only within certain limits and conditions and if the parties agree with it. Besides, the steps taken in developing the arbitration might violate legal and contractual rules applied to it. Given that, this paper deals with how such irregularities can be controlled, analyzing (i) the courts responsible for such control, (ii) the moment when this control is allowed (iii) its legal remedies, and (iv) which irregularities authorize control.

A história de domesticação da cana-de-açúcar (Saccharum spp.) é atípica. As variedades modernas derivam de um processo que inclui hibridações entre a espécie domesticada S. officinarum e a silvestre S. spontaneum, sucessivos retrocruzamentos, no sentido de recuperar o genoma de S. officinarum e a seleção de progênies superiores. Além disso, as genealogias contemplam cruzamentos entre genótipos e eventualmente espécies, todos com elevado grau de ploidia e número de cromossomos distintos, assim como aneuploidias. Frente ao exposto, este trabalho teve como objetivos estabelecer o número de cromossomos e avaliar o comportamento meiótico da cultivar IACSP93-3046, bem como, identificar as associações cromossômicas em meiose I dos genótipos IACSP93-3046, IACSP95-3018 e de um representante de S. officinarum, Caiana Fita, pela marcação dos centrômeros usando FISH. O número de cromossomos da cultivar IACSP93-3046 foi determinado a partir de preparações do meristema radicular, pré-tratado com 8-hidroxiquinolina (0,03%, 4h), e corado pelo método de Feulgen. As células metafásicas foram analisadas sob microscopia óptica, preferencialmente intactas e com o mínimo de sobreposição de cromossomos. Para a análise do comportamento meiótico utilizou-se a técnica de esmagamento, e as células foram coradas com carmim propiônico. Foram observadas as fases meióticas desde a metáfase I até a telófase II, bem como as tétrades. O pareamento cromossômico em meiose I foi analisado usando a técnica de hibridização in situ fluorescente (FISH). Para tanto, preparações dos genótipos IACSP93-3046, IACSP95-3018 e Caiana Fita foram realizadas pelo gotejamento de uma suspensão de células em diacinese. As sondas foram obtidas por PCR a partir da amplificação da região centromérica de cana-de-açúcar, marcadas com digoxigenina-11-dUTP, por nick translation, e detectadas com anti-digoxigenina-rodamina. As lâminas foram montadas em DAPI-Vectashield e analisadas sob microscopia de fluorescência. O número diplóide 2n = 112 foi observado para a cultivar IACSP93-3046, sendo caracterizado pela primeira vez neste estudo. A microsporogênese de IACSP93-3046 apresentou elevado percentual de irregularidades (68%). De modo geral, as anormalidades foram relativas à segregação dos cromossomos, e incluíram migração precoce para os polos em metáfase I e II, cromossomos retardatários em anáfase (I e II) e em telófase (I e II), cromossomos perdidos em prófase II, e micronúcleos nas tétrades. A análise dos sítios de hibridização permitiu comprovar que os cromossomos se associam predominantemente como bivalentes em IACSP93-3046, IACSP95-3018 e Caiana Fita. As irregularidades na segregação dos cromossomos conduzem a micrósporos aneuploides, como constatado em IACSP93-3046. Sugere-se que a assincronia do processo meiótico entre os genomas que compõem a cana-de-açúcar tem papel relevante na geração dessas irregularidades. / The history of the sugarcane domestication (Saccharum spp.) is atypical. Modern varieties are derived from a hybridization process between the domestic species S. officinarum and the wild species S. spontaneum, successive backcrossings to recover the genome of S. officinarum, and the selection of superior progenies. The genealogies include crossings among genotypes, and possibly Saccharum species, all with a high degree of ploidy and different numbers of chromosomes, as well as aneuploidies. The study aimed to establish the number of chromosomes and evaluate the meiotic behavior of cultivar IACSP93-3046, and identify chromosomal associations in meiosis I of genotypes IACSP93-3046, IACSP95-3018 and Caiana Fita (a representative of S. officinarum) by labeling centromeres using fluorescence in situ hybridization (FISH). The number of chromosomes in cultivar IACSP93-3046 was determined from the root meristem preparations, pretreated with 8-hydroxiquinoline and stained by the Feulgen method. Metaphasic cells, preferably intact and with minimum chromosome overlap, were analyzed under an optical microscope. Meiotic behavior was examined from the preparations by using squashing method and stained with propionic carmine. Meiotic phases were observed from metaphase I to telophase II, and tetrad stages. Chromosomal pairing in meiosis I was analyzed by using the FISH technique. The slides of genotypes IACSP93-3046, IACSP95-3018 and Caiana Fita were produced by dropping a suspension of meiocytes in diakinesis. The probes were obtained by PCR, with amplification of the centromere region, and labeled with digoxigenin-11-dUTP, by nick translation, and detected with anti-digoxigenin-rhodamine. The slides were mounted in DAPI-Vectashield and analyzed under a fluorescence microscope. The diploid number 2n = 112 was observed for cultivar IACSP93-3046 and characterized in this study for the first time. Microsporogenesis of IACSP93-3046 presented a high irregularity percentage regarding chromosome segregation, especially precocious migration to poles in metaphase I and II, laggard chromosomes in anaphase and telophase I and II, lost chromosomes in prophase II, and micronuclei in the tetrad stages. The analysis from the hybridization sites proved that the chromosomal pairing occurred predominantly as bivalents in IACSP93-3046, IACSP95-3018 and Caiana Fita. Chromosomal segregation irregularities led to aneuploid microspores, as confirmed in IACSP93-3046, suggesting the asynchrony in the meiotic process between the sugarcane genomes play an important role in producing these irregularities.

Este trabalho trata do problema das vibrações induzidas em estruturas de concreto de pontes ferroviárias, produzidas pela passagem da composição de um TUE (Trem Unidade Elétrico) típico. Partiu-se de um modelo do veículo com nove graus de liberdade, referentes aos deslocamentos verticais e rotações em torno dos eixos longitudinal e transversal, introduzindo-se os graus de liberdade de deslocamentos transversais horizontais e rotações em torno do eixo vertical. Foram calculados os carregamentos provenientes do trem modelado sobre tabuleiro rígido indeslocável, considerando as irregularidades geométricas apresentadas nos trilhos e nas rodas, sendo diferenciada para cada linha de trilho. Estes carregamentos foram condensados estaticamente e aplicados em um modelo estrutural simplificado (unifilar) de uma ponte de seção celular, visando a identificar a resposta dinâmica proveniente das irregularidades geométricas. Finalmente, avalia-se a amplificação dinâmica, a qual é comparada com o valor do coeficiente de impacto prescrito na norma brasileira para projeto de pontes ferroviárias. / This dissertation discusses the problem of induced vibrations in concrete structures of railway bridges, produced by the passing of a typical composition of electric urban trains. It started from a vehicle model with nine degree-of-freedom, related to vertical displacements and rotations around the longitudinal and transverse axes, introducing the degrees-of-freedom of horizontal transverse displacements and rotations around the vertical axis. The trains loads applied to the bridge deck were evaluated, assuming initially a rigid structure under the board, considering the geometric irregularities present in rails and wheels and different for each rail line. These loads were statically reduced to the vehicle center of mass and applied to a simplified bridge structural model, aiming at identifying the dynamic response due to geometric irregularities. Finally the dynamic amplification is evaluated and compared to the value of the impact coefficient prescribed by the Brazilian Standards for design of railway bridges.

The Earth's equatorial ionosphere most often shows the occurrence of large plasma density and velocity fluctuations with a broad range of scale sizes and amplitudes. These night time ionospheric irregularities in the F-region are commonly referred to as equatorial spread F (ESF) or plasma bubbles (EPBs). This dissertation focuses on analysis of ground-based optical and radar measurements to investigate the development and dynamics of ESF, which can significantly disrupt radio communication and GPS navigation systems. OI (630.0 nm) airglow image data were obtained by the Utah State University all-sky CCD camera, primarily during the equinox period, from three different longitudinal sectors under similar solar flux conditions: Christmas Island in the Central Pacific Ocean, Ascension Island in South Atlantic, and Brasilia and Cariri in Brazil. Well-defined magnetic field-aligned depletions were observed from each of these sites enabling detailed measurements of their morphology and dynamics. These data have also been used to investigate day-to-day and longitudinal variations in the evolution and distribution of the plasma bubbles, and their nocturnal zonal drift velocities. In particular, comparative optical measurements at different longitudinal sectors illustrated interesting findings. During the post midnight period, the data from Christmas Island consistently showed nearly constant eastward bubble velocity at a much higher value (~80 m/s) than expected, while data from Ascension Island exhibited a most unusual shear motion of the bubble structure, up to 55 m/s, on one occasion with westward drift at low latitude and eastward at higher latitudes, evident within the field of view of the camera. In addition, long-term radar observations during 1996-2006 from Jicamarca, Peru have been used to study the climatology of post-sunset ESF irregularities. Results showed that the spread F onset times did not change much with solar flux and that their onset heights increased linearly from solar minimum to solar maximum. On average, radar plume onset occurred earlier with increasing solar flux, and plume onset and peak altitudes increased with solar activity. The F-region upward drift velocities that precede spread F onset increased from solar minimum to solar maximum, and were approximately proportional to the maximum prereversal drift peak velocities.

No description available.

In 2001, Fishburn, Tanenbaum, and Trenk published a pair of papers that introduced the notions of linear and weak discrepancy of a partially ordered set or poset. Linear discrepancy for a poset is the least k such that for any ordering of the points in the poset there is a pair of incomparable points at least distance k away in the ordering. Weak discrepancy is similar to linear discrepancy except that the distance is observed over weak labelings (i.e. two points can have the same label if they are incomparable, but order is still preserved). My thesis gives a variety of results pertaining to these properties and other forms of discrepancy in posets. The first chapter of my thesis partially answers a question of Fishburn, Tanenbaum, and Trenk that was to characterize those posets with linear discrepancy two. It makes the characterization for those posets with width two and references the paper where the full characterization is given. The second chapter introduces the notion of t-discrepancy which is similar to weak discrepancy except only the weak labelings with at most t copies of any label are considered. This chapter shows that determining a poset's t-discrepancy is NP-Complete. It also gives the t-discrepancy for the disjoint sum of chains and provides a polynomial time algorithm for determining t-discrepancy of semiorders. The third chapter presents another notion of discrepancy namely total discrepancy which minimizes the average distance between incomparable elements. This chapter proves that finding this value can be done in polynomial time unlike linear discrepancy and t-discrepancy. The final chapter answers another question of Fishburn, Tanenbaum, and Trenk that asked to characterize those posets that have equal linear and weak discrepancies. Though determining the answer of whether the weak discrepancy and linear discrepancy of a poset are equal is an NP-Complete problem, the set of minimal posets that have this property are given. At the end of the thesis I discuss two other open problems not mentioned in the previous chapters that relate to linear discrepancy. The first asks if there is a link between a poset's dimension and its linear discrepancy. The second refers to approximating linear discrepancy and possible ways to do it.

La ricerca si propone di approfondire il tema delle “irregolarità” nelle procedure di adozione internazionale. Questa espressione è utilizzata dalla normativa nazionale di settore, con particolare riferimento all’attività degli enti autorizzati allo svolgimento delle procedure di adozione di minori stranieri. Con questo elaborato si è cercato di ricostruire una nozione di “irregolarità” più ampia di quella presente nella legislazione vigente, privilegiando un approccio interdisciplinare. Lo scritto si apre con una prospettiva storica delle “irregolarità”, ovvero della morfologia che esse hanno assunto nel corso del tempo, in relazione alla disciplina vigente nel nostro Paese a partire dagli anni Sessanta del secolo scorso. Il cuore dell’elaborato è dato dalla presentazione delle “irregolarità”, comprendenti sia alcune illiceità di natura penale ed amministrativa che le criticità della prassi. Chiude l’indagine l’illustrazione di alcune buone pratiche di prevenzione delle “irregolarità” nelle procedure di adozione internazionale e di proposte de iure condendo della disciplina vigente. Particolare attenzione è stata posta al tema della riforma dei delitti in materia di adozione, disposizioni rimaste sostanzialmente disapplicate dagli anni Ottanta ad oggi. / The research aims to delve into “irregularities” in the procedures of the International adoption. The previous mentioned phrase is used in the National specific provisions in reference to activities carried out by accredited bodies, entitled to apply adoption procedures of foreign minors. The thesis is an attempt to reconstruct a broader notion of “irregularity” than those one in the legislation in force, favoring an interdisciplinary approach. Firstly, the dissertation offers an historical perspective on “irregularities”, or rather upon the morphology which they have assumed for years, referring to the discipline which has been in force in Italy since the Sixties of the Twentieth Century. The gist of the thesis is the presentation of such “irregularities”, including both some criminal, administrative, unlawfulness and criticality in standard procedures. Finally, the research presents some good practices in order to prevent such “irregularities” in the International adoption procedures, as well as some de iure condendo proposals of the legislation in force. A specific attention has been paid to the matter of the reform of crimes of adoption, or rather disposals that basically has ceased to be applied since Eighties in the Twentieth Century.

Background: Atherosclerosis is an important cause of stroke. Ultrasound offers the convenience of real-time and detailed assessment of carotid plaque features as well as arterial wall thickening and composition. Evaluation of these features is important for determining patients’ risk of suffering vascular events and also contributes to selecting the best treatment strategy. Methods: Using ultrasound data analysis we have determined plaque features in the bifurcation and internal carotid artery (ICA), including: surface plaque irregularities, calcification, echogenicity (grey scale median-GSM) and other textural plaque features (Juxtaluminal black area, entropy, coarseness). In addition, intima media thickens (IMT) and its grey scale median (IM-GSM) was measured in common carotid artery (CCA). Using Cone Beam CT (CBCT) we have quantified calcification volume of the carotid plaques extracted after carotid endarterectomy procedure. For the meta-analysis we have used comprehensive meta-analysis software version 3. Study I: We have included 39 patients and we compared carotid plaque features of the contralateral arteries with those located ipsilateral to symptomatic side and arteries of asymptomatic patients. Study II: The accuracy of US to detect atherosclerosis calcification was assessed against CBCT in 88 patients. Study III: Based on the previous vascular events in coronary, carotid and lower extremity arterial system, 87 patients were divided into three groups: asymptomatic, symptoms in one vascular system and symptoms in more that one vascular system. IMT, IM-GSM and plaque features were compared between groups. Study IV: We have meta-analyzed ten cohort prospective studies evaluating carotid plaque echogenicity for cerebrovascular symptoms prediction. Results: Study I. Plaques of the contralateral to symptomatic arteries had similar features to those in symptomatic and more vulnerable than asymptomatic arteries. Study II. Carotid ultrasound was accurate in detecting calcification volumes of ≥8mm3 with very high sensitivity but it was less accurate in detecting lower calcification volumes (<8mm3). Carotid calcification was not different between symptomatic and asymptomatic patients. Study III. Echogenicity of the intima-media complex (IM-GSM), but not its thickness (IMT), was significantly decreased with increasing number of arterial systems affected by atherosclerosis. IM-GSM was lower in patients with prior myocardial infarction and stroke. Study IV. Carotid plaque echogenicity evaluated by US could predict future cerebrovascular events in patients with asymptomatic, relative risk RR 2.72 (95% CI, 1.86 to 3.96), and recurrent symptoms in symptomatic patients, RR 2.97 (95% CI, 1.85-4.78). Conclusion: Plaques located in the contralateral to symptomatic arteries have similar features as symptomatic side and more vulnerable than asymptomatic arteries. Carotid ultrasound could accurately detect larger but not smaller carotid plaque calcification volumes (<8 mm3). Low IM- GSM could identify patients with multi-system atherosclerosis disease, suggesting a better marker for determining systemic atherosclerosis disease burden compared to conventional IMT. Finally, carotid plaque echogenicity predicts future cerebrovascular events in patients with symptomatic and asymptomatic carotid stenosis.

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No. of bitstreams: 1 pereira_vas_dr_prud.pdf: 34672414 bytes, checksum: f357f584172b46b5d27f842642bd82f7 (MD5) Previous issue date: 2018-09-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dentre os métodos de posicionamento GNSS (Global Navigation Satellite System) utilizados pela aviação no suporte das fases de aproximação e pouso preciso de aeronaves, destacam-se o SBAS (Satellite-Based Augmentation System) e o GBAS (Ground-Based Augmentation System). O GBAS tem a capacidade de corrigir a maioria dos erros envolvidos na pseudodistância a partir do DGNSS (Differential GNSS), desde que a camada ionosférica apresente um comportamento não perturbado na região do aeroporto. Entretanto, dependendo do fluxo de ionização solar, da atividade geomagnética, do ciclo de manchas solares, do ângulo zenital do Sol e da localização geográfica, a ionosfera pode sofrer fortes perturbações, proporcionando uma ameaça à integridade do GBAS, uma vez que podem ser diferentes os efeitos ionosféricos em pequenas distâncias. Assim, investigações dos erros sistemáticos devido à camada ionosférica no GBAS tem sido objeto de estudos há alguns anos. Nesse sentido, modelos de risco ionosférico, que visam determinar a máxima decorrelação ionosférica espacial existente entre a estação GBAS e a aeronave que se aproxima num aeroporto, foram desenvolvidos ou avaliados, principalmente para o hemisfério norte, mais precisamente para o território norte-americano, onde se destaca o CONUS (Conterminous United States) Threat Model. Nessa área o comportamento da ionosfera é mais estável em comparação com o observado sobre o Brasil, localizado na região ionosférica equatorial e de baixas latitudes, que apresenta a ocorrência da Anomalia de Ionização Equatorial (AIE), bolhas ionosféricas, irregularidades ionosféricas, cintilação ionosférica e Anomalia Magnética do Atlântico Sul (AMAS). A implantação de um GBAS no Brasil, por meio do Departamento de Controle do Espaço Aéreo (DECEA), despertou o interesse de seu uso com segurança. Sendo assim, a pesquisa propôs investigar a aplicabilidade do modelo CONUS de risco ionosférico para GBAS no território brasileiro, utilizando o método dos pares de estações (station-pair method), além de estimar os parâmetros para os principais aeroportos internacionais do Brasil, considerando a variação sazonal, bem como investigar os benefícios quanto ao uso dos sinais GLONASS (Global’naya Navigatsionnaya Sputnikovaya Sistema), Galileo e da portadora L5 do GPS (Global Positioning System) no modelo. Para isso, foram utilizados dados GNSS de várias redes ativas entre os anos de 2000 e 2016, bem como dados do GBAS instalado no aeroporto internacional do Rio de Janeiro/RJ (Galeão). Para a determinação dos parâmetros do modelo de risco e do parâmetro de integridade σvig (vertical ionospheric gradient sigma), esse último utilizado para estimar os níveis de proteção horizontal e vertical da aeronave, foi implementado um sistema denominado MoR_Ion. Os parâmetros do modelo CONUS estimados para o Brasil, utilizando sinais GPS para a combinação de portadoras L1/L2, mostraram que é inviável o uso de um GBAS considerando todo o território nacional. Uma alternativa foi estimativa local e temporal para os aeroportos de interesse. Valores obtidos indicaram que o GBAS pode, provavelmente, ser utilizado nos aeroportos internacionais de São Paulo/SP (Cumbica), Rio de Janeiro/RJ (Galeão), Brasília/DF (Presidente Juscelino Kubitschek) e Recife/PE (Gilberto Freyre) com algumas restrições quanto à estação do ano, hora do dia e elevação dos satélites. Já para o aeroporto internacional de Porto Alegre/RS (Salgado Filho) é o único, entre os analisados, em que nenhuma restrição à instalação do GBAS no local foi identificada a partir do conjunto de dados processados. Resultados empregando os sinais GPS e Galileo, para a combinação L1/L5, apresentaram ser melhores que os da combinação L1/L2. Já em relação ao GLONASS, verificou-se que há uma semelhança com os resultados do GPS. A determinação do σvig em tempo real para cada satélite disponível se apresentou como uma alternativa interessante, uma vez que transmite para a aeronave a real condição ionosférica no momento da aproximação e pouso, ao contrário da atual configuração do GBAS de transmitir um valor fixo de σvig que, teoricamente, contempla todas as possíveis perturbações ionosféricas. Estimativas de níveis de proteção para aproximação no Galeão indicaram que há a possibilidade de se realizar um procedimento CAT-I, utilizando satélites GPS ou GLONASS (combinação L1/L2), desde que sejam aplicadas restrições local-temporais previamente estabelecidas. Verificou-se, também, que a utilização dos satélites GLONASS em concomitância com o GPS possibilita a obtenção de valores que atendem aos limiares para um pouso CAT-III, uma vez que uma maior quantidade de satélites e, consequentemente, uma melhor configuração geométrica, é disponibilizada. Um estudo de caso utilizando o time-step method para a região do aeroporto de São José dos Campos/SP, onde se encontram cinco estações em um raio de 10 km, indicou que gradientes desse método podem ser empregados na estimativa dos valores dos parâmetros. Entretanto, tal método tem pouca semelhança com a arquitetura de uma estação GBAS e uma aeronave que se aproxima e, adicionalmente, não soluciona a decorrelação temporal. Por fim, um método alternativo que pode indicar a realização ou não do pouso consiste no monitoramento das irregularidades ionosféricas em tempo real na região circundante de um determinado aeroporto. Experimento realizado em tempo real, mas utilizando dados GPS e GLONASS de março de 2014 (próximo ao pico do ciclo solar 24), mostrou fortes irregularidades para a região do Galeão, com a frente ionosférica se deslocando de sudoeste a nordeste. Assim, uma medida que pode ser empregada para estimar os níveis de proteção consiste em não utilizar os sinais dos satélites que atravessam tais irregularidades. / Among the methods of GNSS (Global Navigation Satellite System) positioning used by the aviation in the support of the phases of approach and precise landing of aircraft, stand out the SBAS (Satellite-Based Augmentation System) and the GBAS (Ground-Based Augmentation System). GBAS has the ability to correct most of the errors involved in pseudorange from DGNSS (Differential GNSS), provided that the ionospheric layer exhibits undisturbed behavior in the airport region. However, depending on the flow of solar ionization, geomagnetic activity, sunspot cycle, zenith angle of the sun and geographic location, the ionosphere can suffer severe disturbances, posing a threat to the integrity of the GBAS, since the ionospheric effects may be different at small distances. Thus, investigations of systematic errors due to the ionospheric layer in GBAS have been the subject of studies for some years. In this sense, ionospheric threat models, which seek to determine the maximum existing spatial ionospheric decorrelation between the GBAS station and the aircraft approaching an airport, have been developed or evaluated, especially for the northern hemisphere, more precisely to the US territory, which highlights the CONUS (Conterminous United States) Threat Model. In this area, the ionosphere behavior is more stable compared to that observed in Brazil, located in the equatorial and low latitude ionospheric region, which presents the occurrence of Equatorial Ionization Anomaly (EIA), ionospheric bubbles, ionospheric irregularities, ionospheric scintillation and South Atlantic Magnetic Anomaly (SAMA). The implementation of a GBAS in Brazil, through the Department of Airspace Control (DECEA), aroused the interest of its use with safety. Therefore, the research proposed to investigate the applicability of the CONUS Threat Model to GBAS in the Brazilian territory, using the station-pair method, besides estimating the parameters for the main international airports of Brazil, considering the seasonal variation, as well as investigating the benefits of using the GLONASS (Global’naya Navigatsionnaya Sputnikovaya System), Galileo and GPS (Global Positioning System) L5 carrier in the model. For this purpose, GNSS data from several active networks were used between 2000 and 2016, as well as data from GBAS installed at Rio de Janeiro International Airport (Galeão). For the determination of the parameters of the threat model and the σvig (vertical ionospheric gradient sigma) integrity parameter, the latter used to estimate the aircraft horizontal and vertical protection levels, a system called MoR_Ion was implemented. The parameters of the CONUS model estimated for Brazil, using GPS signals for the combination of L1/L2 carriers, showed that it is impracticable to use a GBAS considering the entire national territory. An alternative was a local and temporal estimate for the airports of interest. The values obtained indicate that the GBAS can probably be used in the international airports of São Paulo/SP (Cumbica), Rio de Janeiro/RJ (Galeão), Brasília/DF (President Juscelino Kubitschek) and Recife/PE (Gilberto Freyre) with some restrictions on the season, time of day and satellite elevation. At the international airport of Porto Alegre/RS (Salgado Filho) it is the only one, among the analyzed ones, in which no restriction to the installation of the GBAS in the place was identified from the data set processed. Results using the GPS and Galileo signals for the L1/L5 combination were better than the L1/L2 combination. Regarding GLONASS, it was found that there is a similarity with the GPS results. The determination of the real time σvig for each available satellite was presented as an interesting alternative, since it transmits to the aircraft the actual ionospheric condition at the time of approach and landing, unlike the current GBAS configuration of transmitting a fixed value of σvig which theoretically covers all possible ionospheric disturbances. Estimates of protection levels for approach in Galeão indicated that there is the possibility of performing a CAT-I procedure, using GPS or GLONASS satellites (L1/L2 combination), provided that previously established local-temporal restrictions are applied. It was also verified that the use of GLONASS satellites in concomitance with GPS allows obtaining values that meet the thresholds for a CAT-III landing, since a larger number of satellites and, consequently, a better geometric configuration, is made available. A case study using the time-step method for the airport region of São José dos Campos/SP, where five stations are located within a 10 km radius, indicated that gradients of this method can be used to estimate the parameter values. However, this method has little resemblance to the architecture of a GBAS station and an aircraft approaching and additionally does not solve the temporal decorrelation. Finally, an alternative method that may indicate whether or not the landing is carried out is to monitor ionospheric irregularities in real time in the surrounding region of a given airport. A real-time experiment using GPS and GLONASS data from March 2014 (near the peak of the solar cycle 24) showed strong irregularities for the Galeão region, with the ionospheric front moving from southwest to northeast. Thus, one way that can be used to estimate protection levels is to not use satellite signals that cross such irregularities. / FAPESP: 2015/20522-7