Les colonnes à bulles sont largement utilisées dans les domaines du génie chimique et biologique, grâce à leur configuration simple, exempte de toute partie mobile. Néanmoins, leur extrapolation aux échelles industrielles engendre des modifications de l’hydrodynamique globale (vitesse du liquide, taille des bulles) qui sont encore difficile à prédire avec les outils numériques disponibles.La thèse a pour objectif d’établir une base de données sur l’évolution radiale et axiale de l’hydrodynamique locale (taux de vide, taille de bulles, vitesse liquide), dans différentes tailles de colonnes allant de 0.15 à 3 m de diamètre, pour des vitesses superficielles gaz comprises entre 3 et 35 cm/s, générant des taux de vide atteignant les 35%. Les mesures de taux de vide local, de vitesse de bulles et de la taille verticale des bulles sont réalisées à l’aide d’une sonde optique 1C. De plus, une nouvelle méthode pour mesurer la taille horizontale des bulles à fort taux de vide et en écoulement fortement multidirectionnel est proposée dans cette thèse. Cette méthode est basée sur la corrélation croisée spatiale de signaux provenant de deux sondes optiques placées parallèlement à la même élévation, et à une distance l’une de l’autre devant nécessairement être plus faibles que les bulles les plus petites présentes dans l’écoulement. Les mesures de taille de bulles sont validées en les comparant à un traitement d’images par endoscopie. Pour des vitesses superficielles de gaz supérieures à 9 cm/s, un bon accord est trouvé entre les trois méthodes (sonde optique 1C, corrélation croisée et endoscopie). La taille des bulles augmente légèrement lorsque la vitesse superficielle gaz augmente, par contre elle n’est pas impactée de manière significative par le diamètre des colonnes. Une plus grande ségrégation radiale est tout de même visible dans les plus grandes colonnes testées.Un modèle 1D radial développé pour un écoulement invariant le long de l’axe de la colonne est utilisé pour tester différents formalismes de forces de trainée, utilisant les données expérimentales de taille moyenne de bulles. Les simulations montrent que pour prédire correctement le flux gazeux expérimental, il est nécessaire d’introduire un « swarm factor » (Simonnet et al, 2008) diminuant le coefficient de trainée à fort taux de vide. De plus, des simulations 3D URANS avec Fluent® sont réalisées avec la loi de trainée validée par le modèle 1D précédemment cité. Un bon accord est observé entre les valeurs expérimentales et simulées des profils radiaux de taux de vide et de vitesse liquide, pour des diamètres de colonne allant de 0.4 m à 3 m, et pour des vitesses superficielle gaz de 3 à 35 cm/s. / Bubble columns reactors are widely used in chemical and biological engineering due to its simple configuration without mobile parts. However, the scale-up prediction of a bubble columns reactors is still a challenging process, due to the lack reliable experimental data and models.The present work aims to construct detailed database of the radial and axial evolution of local hydrodynamics properties (gas hold-up, bubble size and velocity, liquid velocity) acquired in several bubble columns in a scale factor of 20 (from 0.15 to 3 m in diameter), for a superficial gas velocity from 3 to 35 cm/s, yielding gas hold-ups up to 35 %. Measurements of local gas hold-up, bubble velocity and bubble vertical size are performed by a 1C mono-fiber optical probe. Moreover, a novel method to measure mean horizontal diameter of bubbles at high void fraction and in a multi-directional flow is proposed. This method is based in the spatial-cross correlation of signal of two optical probes placed parallel side by side, at a given distance from each other, at the same elevation in the column. The validation of the bubble size measurements are performed through a comparison of the results with an endoscopic imaging method. For superficial gas velocities higher than 9 cm/s, a good agreement is found between the three methods (1C mono-fiber optical probe, cross-correlation and endoscopic imaging). A slight increase is registered with the increase of the superficial gas velocity, however there is no significant variation with the column diameter.A 1-D radial model of a bubbly flow (Ueyama and Miyauchi, 1979) developed for a invariant flow along the column axis, is used to benchmark several classic formalisms of the drag force, using experimental average bubble size. Results show that to correctly predict the experimental gas flowrate, it is necessary to use a Swarm factor (Simonnet et al, 2008) that reduces the drag coefficient for high gas hold-up values. Moreover, Fluent® 3D URANS simulations are performed using the previously validated drag force formalism. A good agreement is found between experimental and simulated radial profiles of gas holdup and liquid velocity for column diameters ranging from 0.4 m up to 3 m in diameter in a range of superficial gas velocities from 3 cm/s to 35 cm/s.

Submitted by Pedro Henrique Pereira (pedro.pereirasp@gmail.com) on 2018-06-26T14:21:28Z No. of bitstreams: 1 DissertaçãoPedroHenriquePereira_VersãoFinal.pdf: 4177619 bytes, checksum: 063cd34385c56ed5081e839a845767b5 (MD5) / Approved for entry into archive by Cristina Alexandra de Godoy null (cristina@adm.feis.unesp.br) on 2018-06-26T17:55:12Z (GMT) No. of bitstreams: 1 pereira_ph_me_ilha.pdf: 4177619 bytes, checksum: 063cd34385c56ed5081e839a845767b5 (MD5) / Made available in DSpace on 2018-06-26T17:55:12Z (GMT). No. of bitstreams: 1 pereira_ph_me_ilha.pdf: 4177619 bytes, checksum: 063cd34385c56ed5081e839a845767b5 (MD5) Previous issue date: 2018-04-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho propõe-se um método que envolve diferentes técnicas de processamento digital de imagem para a correção automática de cartão de respostas utilizados em avaliações de múltipla- escolha, vestibulares, concursos ou processos de seleção. O método tem como base um modelo de referência onde são identificados os seguintes elementos do cartão: campos de marcação das opções, número de opção de cada questão e uma imagem de marcação para identificar as extremidades da folha. No trabalho foi aplicada a técnica de Correlação Cruzada Normalizada para identificação da imagem na extremidade da folha. A Transformada de Hough foi utilizada para identificação das áreas onde se realiza a marcação das opções. Para identificar qual a questão que foi marcada utilizou-se a contagem de pixel. Foram realizados testes com 1.154 gabaritos contendo 40 questões, preenchidos no vestibular de uma faculdade particular. O tempo médio para correção de cada cartão foi de 1,39 segundos. A precisão do método foi avaliada utilizando-se 5% dos cartões digitalizados e processados. Basicamente, a avaliação foi realizada conferindo-se visualmente cada cartão e comparando os resultados com os gerados pela correção automática. O índice de acerto com as amostras utilizadas foi de 100%, o que comprova a eficiência do método proposto. / This work proposes a method that involves different techniques of digital image processing for automatic correction of card responses used in multiple-choice evaluations, “vestibular”, contests or selection processes. The method is based on a reference model where the following elements of the card are identified: marking fields of the options, the option number of each question and a marking image to identify the edges of the sheet. In this work, the Normalized Cross-Correlation technique was applied to identify the image at the leaf end. The Hough Transform was used to identify the areas where the options are marked. To identify which question was selected, the pixel count was used. We performed tests with 1.154 templates containing 40 questions that were completed in the entrance examination of a private college. The average time to correct each card was 1.39 seconds. Samples were collected on 5% of the scanned and processed cards by the method to verify their accuracy. The total sampled was visually checked with the results presented by the application of the method and it was verified the percentage of 100% of correct answers in the reading of the markings. / CAPES: 515/2017

Orientador: Jozué Vieira Filho / Resumo: Neste trabalho propõe-se um método que envolve diferentes técnicas de processamento digital de imagem para a correção automática de cartão de respostas utilizados em avaliações de múltipla- escolha, vestibulares, concursos ou processos de seleção. O método tem como base um modelo de referência onde são identificados os seguintes elementos do cartão: campos de marcação das opções, número de opção de cada questão e uma imagem de marcação para identificar as extremidades da folha. No trabalho foi aplicada a técnica de Correlação Cruzada Normalizada para identificação da imagem na extremidade da folha. A Transformada de Hough foi utilizada para identificação das áreas onde se realiza a marcação das opções. Para identificar qual a questão que foi marcada utilizou-se a contagem de pixel. Foram realizados testes com 1.154 gabaritos contendo 40 questões, preenchidos no vestibular de uma faculdade particular. O tempo médio para correção de cada cartão foi de 1,39 segundos. A precisão do método foi avaliada utilizando-se 5% dos cartões digitalizados e processados. Basicamente, a avaliação foi realizada conferindo-se visualmente cada cartão e comparando os resultados com os gerados pela correção automática. O índice de acerto com as amostras utilizadas foi de 100%, o que comprova a eficiência do método proposto. / Abstract: This work proposes a method that involves different techniques of digital image processing for automatic correction of card responses used in multiple-choice evaluations, “vestibular”, contests or selection processes. The method is based on a reference model where the following elements of the card are identified: marking fields of the options, the option number of each question and a marking image to identify the edges of the sheet. In this work, the Normalized Cross-Correlation technique was applied to identify the image at the leaf end. The Hough Transform was used to identify the areas where the options are marked. To identify which question was selected, the pixel count was used. We performed tests with 1.154 templates containing 40 questions that were completed in the entrance examination of a private college. The average time to correct each card was 1.39 seconds. Samples were collected on 5% of the scanned and processed cards by the method to verify their accuracy. The total sampled was visually checked with the results presented by the application of the method and it was verified the percentage of 100% of correct answers in the reading of the markings. / Mestre

Made available in DSpace on 2014-06-11T19:22:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-06-15Bitstream added on 2014-06-13T19:08:03Z : No. of bitstreams: 1 martinhon_g_me_ilha.pdf: 1559279 bytes, checksum: 7e975933281fbe9aec5c7a3556631af8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A estimação do tempo de atraso entre dois sinais de ultra-som é uma tarefa muito comum e importante em diversas aplicações, como em sistemas de posicionamento para medição de distâncias, medidores de espessura em ensaios não-destrutivos, células de medição de propriedades de materiais, entre outros. Em algumas aplicações há necessidade de elevada acurácia e precisão na determinação do tempo de atraso, que dependem de diversos parâmetros do transdutor, de sua excitação e do meio em que a onda se propaga, além do método de estimação e representação numérica. Neste trabalho são avaliados três estimadores de tempo de atraso, com implementações em ponto-fixo e ponto-flutuante: correlação cruzada com interpolação parabólica, transformada de Hilbert da correlação e envoltória do sinal analítico. Os estimadores são avaliados em MATLAB, em ponto-flutuante, com sinais sintetizados e com sinais reais obtidos em laboratório, e em ponto-fixo, usando um processador digital de sinais TMS320VC5416, da Texas Instruments. São explorados parâmetros como freqüência central do transdutor, freqüência de amostragem, largura de banda, relação sinal-ruído e atenuação do meio. O desempenho dos métodos é comparado por meio dos erros médios e desvios-padrão das medidas / Time-delay estimation between two ultrasonic signals is a very common and important task in several applications, such as distance measurement in positioning systems, thickness measurement in nondestructive testing, measurement cells of materials properties, among others. Some applications require high accuracy and precision on the determination of the time-delay, which depend on several transducer parameters, excitation and medium of propagation, as well as the estimation method and numerical representation. In this work, three time-delay estimators are evaluated, with fixed- and floating-point implementations: cross-correlation with parabolic interpolation, Hilbert transform of correlation and analytic signal envelope. The estimators are evaluated in MATLAB with floating-point representation, using synthesized signals and real signals acquired in laboratory, and in fixed-point using a Texas Instruments TMS320VC5416 digital signal processor. Parameters as transducer central frequency, sampling frequency, bandwidth, signal-to-noise ratio and medium attenuation are considered. The performances of the methods are compared by means of errors (or bias) and standard deviations

an Internal Navigational System and a Global Navigational Satellite System (GNSS). In navigational warfare the GNSS can be jammed, therefore are a third navigational system is needed. The system that has been tried in this thesis is camera based navigation. Through a video camera and a sensor reference the position is determined. This thesis will process the matching between the sensor reference and the video image. Two methods have been implemented: normalized cross correlation and position determination through a homography. Normalized cross correlation creates a correlation matrix. The other method uses point correspondences between the images to determine a homography between the images. And through the homography obtain a position. The more point correspondences the better the position determination will be. The results have been quite good. The methods have got the right position when the Euler angles of the UAV have been known. Normalized cross correlation has been the best method of the tested methods.

Com mais de metade de sua produção exportada e participação de aproximadamente um terço do mercado mundial, atualmente o Brasil é o maior exportador de açúcar e, portanto, espera-se que os preços do mercado físico do açúcar no Brasil apresentem algum grau de relacionamento os preços internacionais desta commodity, que são representados pelas cotações dos contratos futuros das bolsas de Nova Iorque (NYBOT) e de Londres (LIFFE) – primeiros vencimentos. No presente estudo são analisadas as relações entre os logaritmos das médias semanais dos preços domésticos de açúcar, representados pelo preço do Estado de São Paulo, principal produtor nacional, e preços internacionais convertidos em moeda brasileira. Utilizando os critérios de Akaike e Schwarz, foi determinado o número de defasagens auto-regressivas necessárias para ajustar modelos com a finalidade de testar a existência de raiz unitária, cujos resultados apontam para a estacionariedade das séries em torno de uma tendência determinista. A partir dos resíduos obtidos na estimação de modelos univariados auto-regressivos para cada variável, foram obtidas as funções de correlação cruzada (FCC) para cada par de variáveis usado no teste de causalidade. Os resultados das FCCs apontam tanto a existência de relação contemporânea significativa, como causalidade dos preços das bolsas internacionais para os preços domésticos do açúcar, sendo mais expressiva a relação causal das cotações dos contratos futuros da bolsa de Nova Iorque para os preços do mercado físico do açúcar no Brasil. Com base nesses resultados, foram especificados modelos que tinham como finalidade analisar o processo de transmissão de preços entre os mercados doméstico e internacional. Para evitar multicolinearidade, optou-se pela não inclusão de defasagens da variável dependente como explicativas nestes modelos e, para contornar problemas associados à correlação de resíduos nas equações ajustadas, as variáveis foram filtradas conforme a metodologia de Cochrane-Orcutt, fundamentando-se nos resultados da função de autocorrelação dos resíduos dos modelos ajustados de forma iterativa. As elasticidades obtidas nas funções de transmissão de preços indicam que os valores passados das cotações da NYBOT são referência para a formação de preço do mercado doméstico de açúcar, e que a influência contemporânea entre os preços das bolsas internacionais e o preço doméstico é pequena. Como a participação do Brasil no mercado internacional de açúcar é elevada, espera-se que de alguma maneira aspectos relativos ao mercado doméstico brasileiro dessa commodity afetem os preços internacionais. Dessa forma, buscou-se analisar o impacto que a produção brasileira de açúcar, a qual define o potencial de exportação dessa commodity pelo Brasil, tem sobre a formação do preço no mercado internacional. Para isso foi ajustada uma função utilizando como representativo do preço de açúcar no mercado internacional a média das cotações do contrato futuro de açúcar na bolsa de Nova Iorque no ano-safra internacional, isto é, entre setembro de um ano a agosto do subseqüente. Como variáveis explicativas foram considerados: o estoque inicial de cada ano-safra, a produção de açúcar do Brasil e a produção de açúcar dos demais países do mundo, também por ano-safra. Os resultados apontam que o direcionamento de mais matéria-prima para a produção de açúcar, considerando as baixas taxas de crescimento do consumo desse produto no mercado interno, tem efeito negativo e significativo no nível de preço a vigorar no mercado internacional. Isto poderia comprometer a rentabilidade do setor, não só porque os preços do açúcar exportado cairiam, mas também porque os menores preços do mercado internacional estariam afetando os recebidos pelo açúcar comercializado no mercado interno. / With more than a half of its production exported and about 30% of market share in the world sugar market, nowadays Brazil is the world’s leading exporter of sugar. So, it’s expected that the sugar physical prices in the State of São Paulo (CEPEA), Brazil´s leading production region, have any sort of relation with the international prices of this commodity. These international prices are represented by the nearby quotes of the sugar contracts at New York Board of Trade (NYBOT) and at London International Financial Futures and Options Exchange (LIFFE), both multiplied by the Brazilian currency exchange rate. The present study analyses the relations between the logarithms of the domestic and international weekly means of sugar prices. The number of auto-regressive lags necessaries to ajust models was determined by Akaike and Scharwz criterions, which objective was to test the existence of unit root. The results pointed to stationary series around deterministic trends. Through the residual data of auto-regressive univariated models that were estimated to each of the variables, it was obtained the cross correlation function (CCF) to each pair of variables to which the causality was tested. The CCF results indicated a significative contemporany relation between the variables and also causality from the international quotes to State of São Paulo domestic prices, mainly from NYBOT. Based on these results, it was obtained the number of lags of the explicative variable to specify the transmission price models between domestic and international sugar prices. To prevent multicolinearity, it was opted to not include lags of dependent variable as explicative variables, and, to skirt problems related to the correlation in the residual data in the adjusted equations, the variables were filtered by the Cochrane-Orcutt methodology, following the indicatives of the autocorrelation function (ACF) of the residual data from adjusted models in an interactive form. The elasticities obtained in the price transmission functions indicated that the past values of NYBOT quotes are reference to CEPEA prices, and that the contemporany influence between domestic and international prices is small. Considering that Brazilian share in the sugar international market is expressive, it’s expected that aspects related to Brazilian domestic market should cause any affect in the international prices level. So, to analyze the impact that Brazilian production of sugar, which defines the potential of exportation of this commodity for Brazil, has on the formation of the price in the international market, it was adjusted a function that uses as representative of the sugar price in the international market the mean of NYBOT nearby quotes between September to August (of the subsequent year). The variables international beginning stocks, Brazilian sugar production and rest of the world sugar production, all of them measured in the international sugar-marketing year, were considered as explicative ones. The results pointed that an increase in the Brazilian sugar cane production (in order to produce sugar), considering the low rates of the consumption evolution in the Brazilian domestic market, would have a negative and significant effect in the international sugar prices level. This event would affect the yield of sugar sector, not only because the sugar international price would decrease, but also because the lower prices in the international market would reduce the Brazilian domestic prices.

Devido à crescente implementação do Controle Preditivo baseado em Modelo (MPC) em outros processos além de refino e plantas petroquímicas, que geralmente possuem múltiplas entradas e saídas, tem-se um aumento na demanda de modelos gerados por identificação de sistemas. Identificar modelos que representem fielmente a dinâmica do processo depende em grande medida das características dos sinais de excitação dos processos. Assim, o foco deste trabalho é realizar um estudo dos sinais típicos usados em identificação de sistemas, PRBS e GBN, em uma abordagem multivariável. O estudo feito neste trabalho parte das características da geração dos sinais individualmente, depois é feita uma análise de correlação cruzada dos sinais de entrada, observando a influência desta sobre os resultados de identificação. Evitar uma alta correlação entre os sinais de entrada permite determinar o efeito de cada entrada sobre a saída no processo de identificação. Um ponto importante no projeto de sinais de identificação de sistemas multivariáveis é a frequência dos mesmos para conseguir excitar os processos nas regiões de frequência de operação normal e assim extrair a maior informação dinâmica possível do processo. As características estudadas são avaliadas por meio de testes em três plantas simuladas diferentes, categorizadas como mal, medianamente e bem condicionadas. Estas implementações foram feitas usando sinais GBN e PRBS de diferentes frequências. Expressões para a caracterização dos sinais de excitação foram avaliadas identificando os processos em malha aberta e malha fechada. Para as plantas mal condicionadas foram implementados sinais compostos por uma parte completamente correlacionada e uma parte não-correlacionada, conhecido como método de dois passos. Finalmente são realizados experimentos de identificação em uma aplicação em tempo real de uma planta piloto de neutralização de pH. Os testes realizados na planta foram feitos visando avaliar os estudos de frequência e correlação em uma aplicaficção real. Os resultados mostram que a condição de sinais completamente descorrelacionados n~ao deve ser cumprida para ter bons resultados nos modelos identificados. Isto permite ter mais exibilidade na geração do conjunto de sinais de excitação. / Due to the Predictive Control based on Model (MPC) rising in other process beyond refining and petrochemical plants, which in general have multiple inputs and outputs, there have been an increase in demand of models generated by system identification. Identify models that accurately represent the dynamics of the process depends largely on the characteristics of the processes excitation signals. Thus, the focus of this work is to perform a study of the typical signals used in identification systems, PRBS and GBN, in a multivariable approach. The study carried out in this work begins on the individual generation characteristics of the signals, and then an analysis is made of input signals cross-correlation, by observing the in uence of this on the identification results. Avoid a high correlation among the input signals allows to determine the effect of each input on the output of the identification process. An important point in the signals design for multivariable system identification is its frequency to get excite the processes in the normal operation frequency regions and thus extract the maximum dynamic information possible of the process. The studied characteristics are evaluated by testing three different simulated plants, categorized as well, medium and ill conditioned. These implementations were made using GBN and PRBS signals of dierent frequencies. Expressions to characterize the excitation signals were evaluated identifying the processes in open and closed-loop. For ill-conditioned plants were implemented signals composed by a fully correlated part and a non-correlated part, known as two-step method. Finally, identification experiments are performed on a real time application in a pilot pH neutralization plant. The tests were made in the plant in order to evaluate the frequency and correlation studies in a real application. The results show that the completely uncorrelated signals condition must not be satisfied to have good results on the identified models, which besides allows greater exibility in the generation of the excitation signals set.

Les travaux réalisés se situent dans le cadre de CSI en mode passif. Une méthode d’identification de défauts se basant sur les fonctions d’inter-corrélations a été proposée et a donné naissance à deux critères d’identifications. Le premier est un critère visuel, ce critère est basé sur la superposition des enveloppes des fonctions d’inter-corrélation obtenues par transformée de Hilbert pour deux configurations dont l’une est sans défaut et l’autre est avec défaut. Le deuxième critère est numérique, il s’agit de la moyenne des écarts entre deux enveloppes que l’on appelle CEI. Les performances de ces critères ont été testées premièrement sur une plaque en aluminium en conditions libres, en utilisant une source localisée en espace ayant une intensité non contrôlée. Les résultats de la première expérience ont montré certes la sensibilité de ces critères à l’apparition des défauts, mais également une forte sensibilité aux changements de la position de la source, c’est pour cette raison qu’une deuxième expérience utilisant une source localisée non localisée en espace à été effectuée. Les critères proposés ont d’abords été testé en utilisant un signal sinus mono fréquence comme source, et en utilisant un bruit blanc filtré comme source par la suite. Grâce aux critères proposés, le défaut est certes identifié, néanmoins, il reste à trouver un moyen pour le localiser et pour le caractériser. / The work presented is in the domain of SHM. An identification method based on the cross correlations functions between piezoelectric sensors was proposed and gave birth to two criterion of identification. The first is a visual criterion, it is based on the superposition of the envelopes of the cross correlation functions obtained by Hilbert transform for two configurations, the first is a defect free configuration of reference and the other is with defect.The second criterion is numerical; it is the mean of the differences between two envelopes. The performance of these criterions was tested first on an aluminum plate in free edges conditions, using a source located in space; the intensity of this source was not controlled. The results of the first experiment has certainly shown the sensitivity of these criterion to the appearance of defects despite the randomness of the source, but also highly sensitivity to changes in the position of the source was found. In the second experiment a source not localized in space was used, and the plate was in clamped edges conditions. The proposed criterions have been tested using a single frequency sine signal as a source first and using a white noise filtered signal secondly. With the proposed criterion, the defect was certainly identified; however, it remains to find a way to locate and to characterize the defect.

This thesis explores problematics of speaker localization using microphone array. Aim of this thesis is implementation of algorithms for speaker localization and experiments with those algorithms. Calculation of TDOA was done using cross-correlation and hyperbolic method was used to calculate position estimation. Finished microphone array is able to locate speaker within certain variance. Results of this thesis allow reader to make assumptions regarding accuracy of localisation using microphone array and ARM kit with limited performance. Precision of position estimation using microphone array reached several decimeters, but this precision is dependent on distance from microphone array.

Ventrolateral medullary neurons have important roles in cardiorespiratory coordination. A rostral extension of the ventral respiratory column (RVRC), including the retrotrapezoid nucleus (RTN), has neurons responsive to local perturbations of CO2 / pH. Respiratory-modulated firing patterns of RVRC neurons are attributed to influences of more caudal (CVRC) neurons. These circuits remain poorly understood. This study addressed the hypothesis that both local interactions and influences from the CVRC shape rostral neuron discharge patterns and responses. Spike trains from 294 rostral and 490 caudal neurons were recorded with multi-electrode arrays along with phrenic nerve activity in 14 decerebrate, vagotomized cats. Overall, 214 rostral and 398 caudal neurons were respiratory-modulated; 124 and 95, respectively, were cardiac-modulated. Subsets of these neurons were evaluated for responses to sequential, selective, transient stimulation of central and peripheral chemoreceptors and arterial baroreceptors. In 5 experiments, Mayer wave-related oscillations (MWROs) in neuronal firing rates were evoked, enhanced, or reduced following central chemoreceptor stimulation. Overall, 174 of the rostral neurons (59.5%) had short- time scale correlations with other RVRC neurons. Of these, 49 triggered cross-correlograms with RVRC targets yielding 330 offset features indicative of paucisynaptic actions from a total of 2,884 rostral pairs evaluated. Forty-nine of the CVRC neurons (10.0%) were triggers in 142 CVRC-RVRC correlograms - from a total of 8,490 - with offset features indicative of actions on RVRC neurons. Correlation linkage maps support the hypothesis that local circuit mechanisms contribute to the respiratory and cardiac modulation of RVRC neurons and their responses to chemoreceptor and baroreceptor challenges.