Distributed LQG control of a water delivery canal with feedforward from measured consumptions

This work addresses the design of distributed LQG controllers for water delivery canals that include feedforward from local farmer water consumptions. The proposed architecture consists of a network of local control agents, each connected to one of the canal pools and sharing information with their neighbors in order to act in a coordinated way. In order to improve performance, the measurement of the outflows from each pool is used as a feedforward signal. Although the feedforward action is local. It propagates due to the coordinates procedure. The paper presents the distributed LQG algorithm with feedforward and experimental results in a large scale pilot water delivery canal

Fault Tolerant Reconfigurable Control of a Water Delivery Canal - Actuators Faults

This work addresses the problem of designing fault tolerant controllers for a water delivery canal that tackle actuators faults. The type of faults considered consists of blocking of one of the gates. The detection of the fault is made by comparing the gate position command with the actual (measured) gate position. Both centralized and distributed controllers are made for local upstream water level control. Centralized controllers are multivariable LQG-LTR controllers that use a model of the system with all the available manipulated inputs (gate positions) and all the available outputs (pool levels). Initially, three gates and three pools are controlled. After the fault detection, the controller is reconfigured to use the only two still operating gates and the corresponding two pool water levels. Distributed control uses local (SISO) LQG-LTR controllers that negotiate with their neighbors in order to be coordinated. When a fault occurs, this negotiation takes place only among the controllers connected to the actuators that are not in a fault state. Experimental results obtained in a pilot canal are presented

Mecanismos de asimilación de hierro en Photobacterium damselae: similitudes y particularidades

La especie Photobacterium damselae está subdividida en 2 subespecies: damselae (PDP) y piscicida (PDP). PDP es el agente causal de la fotobacteriosis en peces, mientras que PDD afecta a gran variedad de animales marinos, y es un patógeno oportunista para humanos. Ambas subespecies poseen diversos mecanismos de asimilación de hierro. Así, ambas comparten los mecanismos de utilización del grupo hemo como fuente de hierro. Los genes que codifican estos sistemas son prácticamente idénticos en las dos subespecies. Además, parecen compartir otro sistema basado en la utilización de citrato endógeno. Por otra parte, PDD y PDP poseen sistemas específicos de asimilación de hierro basados en la síntesis de sideróforos. En PDP el único sideróforo identificado es la piscibactina, cuya síntesis está codificada en un plásmido movilizable. Este sideróforo juega un papel crucial en la virulencia de las cepas que lo poseen. PDD no posee piscibactina. En esta subspecie existe una gran diversidad intraespecífica en cuanto a los mecanismos de asimilación de hierro. En algunas cepas se ha demostrado la producción de vibrioferrina, un sideróforo común en algunas especies de Vibrio, codificado en una isla genómica. Sin embargo, en otras cepas de PDD el único sistema presente parece ser la producción de citrato endógeno y en otro grupo de cepas el mecanismo concreto es desconocido. Por tanto, a pesar de su elevada proximidad genética, las dos subspecies de P. damselae poseen una gran diversidad en cuanto a sus mecanismos de asimilación de hierro, lo que probablemente contribuye a que puedan colonizar diferentes hábitats y hospedadores. Algunos de estos sistemas pueden también ser aprovechados como dianas para el desarrollo de nuevos tratamientos para combatir las infecciones causadas por estas dos bacterias.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Using GIS to Predict Corn Yields in Colombia

Crop yield prediction can play an important role in developing the agriculture sector in Colombia. Remote sensing and GIS have proven to be an effective mechanism for this purpose in developed economies. This project created a proof-of-concept application for the Colombian Ministry of Agriculture and other related governmental institutions. The project used existing methodologies including the classification of satellite imagery, interpolation of climate data into continuous surfaces, the extraction of Normalized Difference Vegetation Index, and the computation of multiple linear regressions. ESRI ArcGIS provided the interface, software, tools and functions to build the application, and to integrate and automate the application‟s functionalities. Cloud coverage in the imagery and the lack of specialized data affected the accuracy of the crop yields estimates. Nevertheless, the application predicts corn yields with an estimated accuracy of 71% when cloud coverage is minimal. The application can use both Landsat and Spot preprocessed images, and in less than six minutes yield predictions for areas inside Cordoba, a major corn producing state in Colombia

Control of a water delivery canal with cooperative distributed MPC

This article addresses the problem of controlling pool levels in a water delivery canal using a novel cooperative distributed MPC control algorithm that incorporates stability constraints. According to a distributed control strategy, a local control agent is associated to all canal gates (actuators). In order to achieve cooperative action, each control agent computes the corresponding gate position (manipulated variable) by performing the minimization of a cost function that considers not only its local control objectives, but also the ones of their immediate neighbors. For this purpose, a MPC algorithm with stability constraints is used (SIORHC). At the beginning of each sampling interval, local control agents exchange information with their neighbors and adjust their decision in an iterative way. The resulting distributed MPC is denoted D-SIORHC and yields a stable closed-loop. Experimental results are provided to show the influence of the controller configuration parameters on the resulting performance

Charged polytropic compact stars

In this work, we analyze the effect of charge in compact stars considering the limit of the maximum amount of charge they can hold. We find that the global balance of the forces allows a huge charge (~ 10^{20} Coulomb) to be present in a neutron star producing a very high electric field (~ 10^{21} V/m). We have studied the particular case of a polytropic equation of state and assumed that the charge distribution is proportional to the mass density. The charged stars have large mass and radius as we should expect due to the effect of the repulsive Coulomb force with the M/R ratio increasing with charge. In the limit of the maximum charge the mass goes up to ~ 10 M_sun which is much higher than the maximum mass allowed for a neutral compact star. However, the local effect of the forces experienced by a single charged particle, makes it to discharge quickly. This creates a global force imbalance and the system collapses to a charged black hole

Cardiovascular tolerance and safety of intravenous lidocaine in the broiler chicken (Gallus gallus domesticus)

Lidocaine, an amide local anesthetic agent, is commonly used in mammals, including humans. There is a general assumption that birds are more sensitive to lidocaine than mammals. Relatively low doses of lidocaine have been suggested to cause toxic effects in birds. While this information appears to be anecdotal, it has been perpetuated in the literature. The overall objective of this thesis research was to determine the tolerance and safety of intravenous lidocaine in broiler chickens. To assess the cardiovascular effects of lidocaine, relative changes on heart rate and mean blood pressure were calculated. Clinically significant cardiovascular effects were defined as relative decrease of heart rate and/or mean blood pressure equal to or greater than 30%. On the first study, doses below the reported toxic dose were assessed. The effects of 2.5, 3.0, 3.5 mg/kg intravenous lidocaine were compared with a control (saline) group. Each dose was used in 2 randomly selected animals. No significant cardiovascular effects were detected; therefore, higher doses were investigated. On a 2nd study, using an up-and-down study design, a total of 11 subjects were evaluated. The up-and-down method is a sequential design with binary response variables within a certain population which allows the determination of an effective dose to 50% of the population (ED50). The ED50 was defined as the dose that would cause clinically insignificant cardiovascular depression to 50% of the population. Using two statistical methods, the ED50 of cardiovascular function was 6.3 mg/kg and 6.22 mg/kg (95% confidence interval, 5.3 – 7.13 mg/kg). The safety of this dose was then tested in a new group of broiler chickens. The dose of 6 mg/kg was administered to 6 animals. No clinically significant cardiovascular effects were detected in any animal. In conclusion, the 3 studies performed for this thesis indicates that the reported toxic dose of lidocaine appears to be erroneous. Furthermore, this thesis determined the highest tolerable dose and its safety in a specific group of broiler chickens. Further studies assessing analgesia and anesthetic effects of lidocaine are necessary, both in chickens and other avian species

Ordenamento da paisagem e conservação do património arqueológico

A conservação sistemática e intransigente dos sítios e solos arqueológicos e um imperativo das nações europeias. Actualmente já não se aceitam as destruições acidentais ou voluntárias do património arqueológico. Nos Estados modernos existem leis e organismos que protegem e gerem os valores arqueológicos. A opinião pública adquiriu uma extrema sensibilidade no que concerne a conservação

Antes de Bracara Augusta

Ao longo de mais de três décadas, primeiro como vogal da Comissão Instaladora da Universidade do Minho depois como Vice-Reitor, Reitor e, finalmente, como Presidente do Conselho Cultural da UM o Professor Lúcio Craveiro da Silva foi um apoiante inabalavel do Salvamento e Estudo de Bracara Augusta. Nos momentos de maior incerteza nunca duvidou do valor do projecto, garantindo a sua continuidade. Esteve sempre presente nas sucessivas conferências, normalmente realizadas no Museu Nogueira da Silva, em que se divulgavam as descobertas arqueológicas. Lia atentamente todos ao artigos sobre a Arqueologia de Braga, publicados quer nos Cadernos de Arqueologia, quer na Revista Forum. Orgulhava-se do contributo decisivo da Universidade do Minho para o estudo e conservação dos vestígios de uma das grandes cidades da Hispania e do Império. No entanto, para o Professor Lucio Craveiro da Silva a dinâmica do Conhecimento era mais importante que o Patrimonio Cultural, como entidade estática. Aliás, na sua perspectiva, Conhecimento e Cultura eram indissociáveis