A nonlinear controller based on saturation functions with variable parameters to stabilize an AUV

Campos, E.,Monroy, J.,Abundis, H.,Chemori, A.,Creuze, V.,Torres, J. The Society of Naval Architects of Korea 2019 International Journal of Naval Architecture and Oc Vol.11 No.1

This paper deals with a nonlinear controller based on saturation functions with variable parameters for set-point regulation and trajectory tracking control of an Autonomous Underwater Vehicle (AUV). In many cases, saturation functions with constant parameters are used to limit the input signals generated by a classical PD (Proportional-Derivative) controller to avoid damaging the actuators; however this abrupt bounded harms the performance of the controller. We, therefore, propose to replace the conventional saturation function, with constant parameters, by a saturation function with variable parameters to limit the signals of a PD controller, which is the base of the nonlinear PD with gravitational/buoyancy compensation and the nonlinear PD + controllers that we propose in this paper. Consequently, the mathematical model is obtained, considering the featuring operation of the underwater vehicle LIRMIA 2, to do the stability analysis of the closed-loop system with the proposed nonlinear controllers using the Lyapunov arguments. The experimental results show the performance of an AUV (LIRMIA 2) for the depth control problems in the case of set-point regulation and trajectory tracking control.

Contributions of visual and proprioceptive information to travelled distance estimation during changing sensory congruencies

Campos, Jennifer L.,Butler, John S.,Bü,lthoff, Heinrich H. Springer-Verlag 2014 Experimental brain research Vol.232 No.10

Convergence of a linearly transformed particle method for aggregation equations

Campos Pinto, Martin,Carrillo, José,A.,Charles, Fré,dé,rique,Choi, Young-Pil Springer Berlin Heidelberg 2018 Numerische Mathematik Vol.139 No.4

<P>We study a linearly transformed particle method for the aggregation equation with smooth or singular interaction forces. For the smooth interaction forces, we provide convergence estimates in [FORMULA OMISSION] and [FORMULA OMISSION] norms depending on the regularity of the initial data. Moreover, we give convergence estimates in bounded Lipschitz distance for measure valued solutions. For singular interaction forces, we establish the convergence of the error between the approximated and exact flows up to the existence time of the solutions in [FORMULA OMISSION] norm.</P>

Genetic Parameters for Linear Type Traits and Milk, Fat, and Protein Production in Holstein Cows in Brazil

Campos, Rafael Viegas,Cobuci, Jaime Araujo,Kern, Elisandra Lurdes,Costa, Claudio Napolis,McManus, Concepta Margaret Asian Australasian Association of Animal Productio 2015 Animal Bioscience Vol.28 No.4

The objective of this study was to estimate genetic and phenotypic parameters for linear type traits, as well as milk yield (MY), fat yield (FY) and protein yield (PY) in 18,831 Holstein cows reared in 495 herds in Brazil. Restricted maximum likelihood with a bivariate model was used for estimation genetic parameters, including fixed effects of herd-year of classification, period of classification, classifier and stage of lactation for linear type traits and herd-year of calving, season of calving and lactation order effects for production traits. The age of cow at calving was fitted as a covariate (with linear and quadratic terms), common to both models. Heritability estimates varied from 0.09 to 0.38 for linear type traits and from 0.17 to 0.24 for production traits, indicating sufficient genetic variability to achieve genetic gain through selection. In general, estimates of genetic correlations between type and production traits were low, except for udder texture and angularity that showed positive genetic correlations (>0.29) with MY, FY, and PY. Udder depth had the highest negative genetic correlation (-0.30) with production traits. Selection for final score, commonly used by farmers as a practical selection tool to improve type traits, does not lead to significant improvements in production traits, thus the use of selection indices that consider both sets of traits (production and type) seems to be the most adequate to carry out genetic selection of animals in the Brazilian herd.

Responses of Guava Plants to Inoculation with Arbuscular Mycorrhizal Fungi in Soil Infested with Meloidogyne enterolobii

Campos, Maryluce Albuquerque Da Silva,Silva, Fabio Sergio Barbosa Da,Yano-Melo, Adriana Mayumi,Melo, Natoniel Franklin De,Pedrosa, Elvira Maria Regis,Maia, Leonor Costa The Korean Society of Plant Pathology 2013 Plant Pathology Journal Vol.29 No.3

In the Northeast of Brazil, expansion of guava crops has been impaired by Meloidogyne enterolobii that causes root galls, leaf fall and plant death. Considering the fact that arbuscular mycorrhizal Fungi (AMF) improve plant growth giving protection against damages by plant pathogens, this work was carried out to select AMF efficient to increase production of guava seedlings and their tolerance to M. enterolobii. Seedlings of guava were inoculated with 200 spores of Gigaspora albida, Glomus etunicatum or Acaulospora longula and 55 days later with 4,000 eggs of M. enterolobii. The interactions between the AMF and M. enterolobii were assessed by measuring leaf number, aerial dry biomass, $CO_2$ evolution and arbuscular and total mycorrhizal colonization. In general, plant growth was improved by the treatments with A. longula or with G. albida. The presence of the nematode decreased arbuscular colonization and increased general enzymatic activity. Higher dehydrogenase activity occurred with the A. longula treatment and $CO_2$ evolution was higher in the control with the nematode. More spores and higher production of glomalin-related soil proteins were observed in the treatment with G. albida. The numbers of galls, egg masses and eggs were reduced in the presence of A. longula. Inoculation with this fungus benefitted plant growth and decreased nematode reproduction.

Multisensory integration in the estimation of walked distances.

Campos, Jennifer L,Butler, John S,B?lthoff, Heinrich H Springer-Verlag 2012 Experimental brain research Vol.218 No.4

<P>When walking through space, both dynamic visual information (optic flow) and body-based information (proprioceptive and vestibular) jointly specify the magnitude of distance travelled. While recent evidence has demonstrated the extent to which each of these cues can be used independently, less is known about how they are integrated when simultaneously present. Many studies have shown that sensory information is integrated using a weighted linear sum, yet little is known about whether this holds true for the integration of visual and body-based cues for travelled distance perception. In this study using Virtual Reality technologies, participants first travelled a predefined distance and subsequently matched this distance by adjusting an egocentric, in-depth target. The visual stimulus consisted of a long hallway and was presented in stereo via a head-mounted display. Body-based cues were provided either by walking in a fully tracked free-walking space (Exp. 1) or by being passively moved in a wheelchair (Exp. 2). Travelled distances were provided either through optic flow alone, body-based cues alone or through both cues combined. In the combined condition, visually specified distances were either congruent (1.0) or incongruent (0.7 or 1.4) with distances specified by body-based cues. Responses reflect a consistent combined effect of both visual and body-based information, with an overall higher influence of body-based cues when walking and a higher influence of visual cues during passive movement. When comparing the results of Experiments 1 and 2, it is clear that both proprioceptive and vestibular cues contribute to travelled distance estimates during walking. These observed results were effectively described using a basic linear weighting model.</P>

A D-Band Subharmonically-Pumped Resistive Mixer Based on a 100 nm MHEMT Technology

Y. Campos-Roca,A. Tessmann,H. Massler,A. Leuther 한국전자통신연구원 2011 ETRI Journal Vol.33 No.5

A D-band subharmonically-pumped resistive mixer has been designed, processed, and experimentally tested. The circuit is based on a 180-degree power divider structure consisting of a Lange coupler followed by a lambda/4 transmission line (at local oscillator (LO) frequency). This monolithic microwave integrated circuit (MMIC) has been realized in coplanar waveguide technology by using an InAlAs/InGaAs-based metamorphic high electron mobility transistor process with 100-nm gate length. The MMIC achieves a measured conversion loss between 12.5 dB and 16 dB in the radio frequency bandwidth from 120 GHz to 150 GHz with 4-dBm LO drive and an intermediate frequency of 100 MHz. The input 1-dB compression point and IIP3 were simulated to be 2 dBm and 13 dBm, respectively.

Adjuvant therapy with 1% alendronate gel for experimental periodontitis treatment in rats

de Campos Kajimoto, Natalia,de Paiva Buischi, Yvonne,Loomer, Peter Michael,Bromage, Timothy G.,Ervolino, Edilson,Fucini, Stephen Enrico,Pola, Natalia Marcumini,Pirovani, Beatriz Ommati,Morabito, Maria Korean Academy of Periodontology 2021 Journal of Periodontal & Implant Science Vol.51 No.-

Purpose: The aim of this study was to evaluate the effects of locally delivered 1% alendronate (ALN) gel used as an adjunct to non-invasive periodontal therapy. Methods: Ligature-induced periodontitis was performed in 96 rats. The ligature was tied in the cervical area of the mandibular left first molar. The animals were randomly divided into 4 groups: 1) NT, no treatment; 2) SRP, scaling and root planning; 3) SRP/PLA, SRP followed by filling the periodontal pocket with placebo gel (PLA); and 4) SRP/ALN, SRP followed by filling the periodontal pockets with 1% ALN gel. Histomorphometric (percentage of bone in the furcation region [PBF]) and immunohistochemical (receptor activator of nuclear factor-κB ligand, osteoprotegerin, and tartrate-resistant acid phosphatase) analyses were performed. Data were statistically analyzed, with the threshold of statistical significance set at P≤0.05. Results: The SRP, SRP/PLA, and SRP/ALN groups presented a higher PBF than the NT group (P≤0.01) at 7, 15, and 30 days. The SRP/ALN group presented a higher PBF than the SRP/PLA group in all experimental periods, as well as a higher PBF than the SRP group at 15 and 30 days. No differences were observed in the immunohistochemical analyses (P>0.05 for all). Conclusions: Locally delivered 1% ALN gel used as an adjunct to SRP enhanced bone regeneration in the furcation region in a rat model of experimental periodontitis.

Temporal Variation in Size-Class and Tempo-Spatial Variation in Proportion of Reproductive Fronds of Amphiroa vanbosseae (Corallinales, Rhodophyta) in the Southwestern Gulf of California, Mexico

Rivera-Campos, Rocio U.,Riosmena-Rodriguez, Rafael The Korean Society of Phycology 2003 ALGAE Vol.18 No.1

Montmorillonite clay intercalated with nanoparticles for hydrogen storage

Fabiola Campos,Luis de la Torre,Manuel Román,A. García,A. Aguilar Elguézabal 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.5

According to the expectations around the world concerning future of energy sources, hydrogen will be in a few years the most important energy carrier for stationary and mobile applications. Hydrogen storage is the bottleneck on the race to commercialize technologies based on the use of hydrogen, and specifically for mobile applications, the research goal for 2010 is to develop a device with at least 6% w/w of storage capacity. Highly porous carbon-based materials are among the most promising materials, with Carbon Molecular Sieves CMS) and Carbon Nanotubes (CNT) the most studied. In both cases materials are structured in such a way that hydrogen must diffuse along channels (micropores) where walls represent a restriction for the adsorption/desorption cycle. In this study, an alternative material is prepared by separation of clay layers with silica nanoparticles of diameter around 12 nm. The hydrogen storage capacity increased from 0.12 for untreated clay to 0.40% w/w for nanoassembled clay, measured at 77 K and atmospheric pressure, and according to intercalated clay characterization, almost all the surface available on the clay was exposed for adsorption. According to the expectations around the world concerning future of energy sources, hydrogen will be in a few years the most important energy carrier for stationary and mobile applications. Hydrogen storage is the bottleneck on the race to commercialize technologies based on the use of hydrogen, and specifically for mobile applications, the research goal for 2010 is to develop a device with at least 6% w/w of storage capacity. Highly porous carbon-based materials are among the most promising materials, with Carbon Molecular Sieves CMS) and Carbon Nanotubes (CNT) the most studied. In both cases materials are structured in such a way that hydrogen must diffuse along channels (micropores) where walls represent a restriction for the adsorption/desorption cycle. In this study, an alternative material is prepared by separation of clay layers with silica nanoparticles of diameter around 12 nm. The hydrogen storage capacity increased from 0.12 for untreated clay to 0.40% w/w for nanoassembled clay, measured at 77 K and atmospheric pressure, and according to intercalated clay characterization, almost all the surface available on the clay was exposed for adsorption.