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

Gaussian random field-based log odds occupancy mapping

This paper focuses on mapping problem with known robot pose in static environments and proposes a Gaussian random field-based log odds occupancy mapping (GRF-LOOM). In this method, occupancy probability is regarded as an unknown parameter and the dependence between parameters are considered. Given measurements and the dependence, the parameters of not only observed space but also unobserved space can be predicted. The occupancy probabilities in log odds form are regarded as a GRF. This mapping task can be solved by the well-known prediction equation in Gaussian processes, which involves an inverse problem. Instead of the prediction equation, a new recursive algorithm is also proposed to avoid the inverse problem. Finally, the proposed method is evaluated in simulations

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

High-energy diets and Diabetes Mellitus: a threat for male fertility

A sobrevivência do ser humano reside numa fertilidade saudável, no entanto, nos últimos anos tem-se observado um declínio na fertilidade masculina. Este problema tem particular incidência nas sociedades modernas, e a curto prazo estará presente nos países em desenvolvimento. Factores externos associados ao estilo de vida, tais como maus hábitos alimentares, particularmente a ingestão excessiva de dietas de alta energia, têm contribuído para o aumento de doenças metabólicas, nomeadamente a obesidade e a diabetes mellitus (DM). Na verdade, a combinação de factores como: mudanças na composição de alimentos; aumento do consumo de dietas de alta energia; consumo de alimentos com altos níveis de açúcar e gorduras saturadas de elevada palatibilidade; o sedentarismo e a falta de atividade física são a principal causa para o incremento destas patologias. A obesidade e a DM são problemas de saúde pública nos países desenvolvidos e a sua incidência tem vindo a aumentar rapidamente entre os homens em idade reprodutiva, contribuindo para o surgimento da subfertilidade e infertilidade nesses indivíduos. A desregulação metabólica e endócrina associada a estes estadios patológicos compromete a função reprodutora masculina, uma vez que o eixo hipotálamo-hipófise-testículo, também conhecido como eixo reprodutivo, é sensível a alterações metabólicas. O tecido testicular é composto por uma população heterogénea de células somáticas e germinativas. As células germinativas estão dependentes do apoio nutricional fornecido pelas células de Sertoli, e distúrbios metabólicos podem perturbar essa cooperação metabólica. O metabolismo das células testiculares, em particular o das células de Sertoli, apresenta características únicas, uma vez que estas células são capazes de metabolizar vários substratos (e.g.: glucose, ácidos gordos, corpos cetónicos). As células de Sertoli metabolizam preferencialmente a glucose, sendo que a maioria desta é convertida a lactato, e não oxidada através do ciclo de Krebs. Os mecanismos que regulam o metabolismo das células de Sertoli são essenciais para a espermatogénese, e este processo metabólico é controlado por vários fatores, entre eles a insulina e as hormonas esteróides sexuais. Doenças metabólicas, como a DM, apresentam na sua origem resistência à insulina e/ou ausência de insulina, bem como uma incapacidade de as células responderem de forma eficiente à estimulação por esta hormona. Dada a importância da insulina no metabolismo da glucose e o facto de as células de Sertoli expressam receptores específicos para esta hormona, avaliámos o comportamento metabólico das células de Sertoli em situações de privação de insulina. Nestas condições, as células de Sertoli alteram o seu metabolismo glicolítico, diminuíndo a taxa de produção de lactato através da modulação da expressão de proteínas associadas à produção e exportação de lactato, sugerindo que são afectadas na sua actividade metabólica em condições patológicas associadas à desregulação da insulina, como é o caso da DM. No entanto, a DM induz uma desregulação endócrina generalizada. Uma consequência directa da DM na função testicular é a inibição da síntese de testosterona (T). Neste trabalho, demonstramos que os esteróides sexuais, particularmente a testosterona (e o seu metabolito 5α-di-hidrotestosterona) e o 17β-estradiol (E2), modulam o metabolismo glicolítico das células de Sertoli, favorecendo o consumo de glucose, sem contudo promoverem a síntese de lactato. De facto, a produção de lactato, que é o principal substrato para o desenvolvimento das células germinativas, encontrava-se diminuída pela acção androgénica, o que poderá resultar num comprometimento da cooperação metabólica testicular. Quanto mais severo é o estado de progressão da DM, maior é a redução dos níveis da T. Desta forma, estudámos os efeitos da desregulação dos níveis da T induzidos por diferentes estadios da DM, pré-diabetes e diabetes mellitus tipo 2 no metabolismo glicolítico das células de Sertoli. Os resultados mostraram que quanto mais avançado é o estado da doença, mais a via glicolítica está comprometida, verificando-se igualmente uma alteração mais acentuada na maquinaria celular associada à produção de lactato em células em cultura com níveis de T associados à diabetes mellitus tipo 2. Curiosamente, as células de Sertoli em cultura em condições de T similares ao observado no estado de diabetes mellitus tipo 2 mostram que são capazes de adoptar mecanismos que promovem o uso de substratos alternativos, como é o caso do glicogénio. Ao nível do testículo, evidenciou-se que o estado de pré-diabetes induzido pelo consumo de dietas de alta energia também altera o metabolismo glicolítico. Nestas condições, a via glicolítica está favorecida devido ao aumento da expressão e actividade de proteínas essenciais que intervêm nessa via metabólica. Também a expressão de proteínas associadas à produção de lactato está aumentada, o que parece contribuir para o aumento observado no lactato testicular. No entanto, e apesar da adaptação metabólica evidenciada, os parâmetros reprodutivos são seriamente afectados, o que pode resultar do favorecimento de um ambiente testicular oxidativo. De facto, nessas condições observou-se uma diminuição significativa da expressão de proteínas envolvidas tanto na manutenção da biogénese mitocondrial, como na activação do sistema de defesa contra as espécies reactivas de oxigénio. O potencial antioxidante testicular diminuído, assim como, a alteração na respiração mitocondrial testicular contribuíram igualmente para uma deficiente capacidade bioenergética e um aumento do ambiente oxidativo. Já em estadios mais avançados da DM, como é o caso da diabetes mellitus tipo 2, observou-se que o metabolismo glicolítico testicular é seriamente comprometido. A actividade da lactato desidrogenase está severamente diminuída, contribuindo para uma diminuição do conteúdo em lactato neste tecido. Porém, nestas condições destaca-se a adaptação verificada no metabolismo testicular, que promoveu um aumento do conteúdo de glicogénio nos testículos. Estes resultados indicam que a diabetes mellitus tipo 2 induz uma reprogramação metabólica testicular, promovendo vias metabólicas alternativas. No entanto, os parâmetros espermáticos dos indivíduos que sofriam desta condição estavam comprometidos, visto que a motilidade e viabilidade dos espermatozóides estavam acentuadamente diminuídas e o número de espermatozóides com anomalias na morfologia era elevado. Em conclusão, este trabalho demonstra que as doenças metabólicas, particularmente a DM, podem contribuir para uma diminuição do potencial reprodutivo masculino induzindo alterações profundas no metabolismo celular do testículo, e em particular no metabolismo das células de Sertoli. O processo da espermatogénese é complexo e, do ponto de vista fisiológico, o metabolismo glicolítico é essencial para o sucesso deste evento celular. A regulação do metabolismo da glucose nas células de Sertoli é alvo de vários factores, e tanto nos estadios iniciais da DM, como nos estadios mais avançados, sofre alterações, sendo que são mais pronunciadas em estadios avançados da doença. De facto, verificou-se que em estadios iniciais da DM o metabolismo testicular tende a adaptar-se de modo a assegurar a produção de lactato para as células germinativas em desenvolvimento. Todavia com a progressão da doença, a produção desse metabolito energético é seriamente comprometida. De facto, estas alterações metabólicas progressivas estão ainda associadas a uma diminuição dos parâmetros espermáticos, que seguramente serão responsáveis pelo declínio da saúde reprodutiva masculina.The survival of the human being lies in a healthy fertility, however, in last decades it has been observed a decline in male fertility. This problem has a particular focus in modern societies, but in the near future will be present in developing countries. External factors associated with lifestyle, such as erroneous eating habits, particularly the excessive intake of high energy diets, have contributed to the increase of metabolic diseases, including obesity and diabetes mellitus (DM). Indeed, the combination of factors such as: changes in the composition of foods, increased consumption of high-energy diets, consumption of foods with high levels of sugar and saturated fats, sedentary lifestyle and the lack of physical activity are the main cause for the increase of this pathology. Obesity and DM are public health problems in developed countries and its incidence has been increasing rapidly among men of reproductive age, contributing to the emergence of subfertility and infertility in these individuals. The metabolic and hormonal dysregulation associated with these pathological stages compromises the male reproductive function, since the hypothalamus-pituitary gonadal axis, also known as reproductive axis, is sensitive to the subtle metabolic disturbances. Testicular tissue consists of a heterogeneous population of somatic and germ cells, where germ cells are dependent on the nutritional support provided by Sertoli cells and any metabolic disorder may alter this metabolic cooperation. Metabolism of testicular cells, in particular of Sertoli cells, present some unique features. Sertoli cells are able to metabolize various substrates (e.g.: glucose, fatty acids, ketone bodies), preferentially metabolizing glucose, being the majority of it converted to lactate and not oxidized via Krebs’ cycle. The mechanisms that regulate the metabolism of Sertoli cells are essential for spermatogenesis and this metabolic process is regulated by several factors, among which insulin and sexual steroid hormones play an important role. Metabolic diseases, such as DM, present in its origin insulin resistance and/or absence, as well as an inability of cells to efficiently respond to insulin stimulation. Given the relevance of this hormone on glucose metabolism and the fact that Sertoli cells express the specific receptors for insulin, we evaluated the metabolic behavior of Sertoli cells under insulin deprivation conditions. In these circumstances, Sertoli cells altered their glycolytic metabolism, decreasing the rate of lactate production through the modulation of the expression of proteins associated with the production and export of lactate. This suggests that Sertoli cells are affected in their metabolic activity under specific pathological conditions associated with insulin deregulation, such is the case of DM. DM induces a generalized endocrine disruption. A direct consequence of DM on testicular function is the inhibition of the synthesis of testosterone (T) and the more severe is the state of DM, the greater the reduction in levels of T. In this work, we showed that the sex steroids, particularly testosterone (and its non aromatizable metabolite 5-dihydrotestosterone) and 17β-estradiol, modulate the glycolytic metabolism of Sertoli cells, favoring the increase of glucose consumption, although the production of lactate is not promoted. In fact, lactate production, which is the primary substrate of developing germ cells, is diminished by the androgenic action. We further studied the effects of T deficiency induced by different stages of DM, pre-diabetes and type 2 diabetes mellitus, in the glycolytic metabolism of Sertoli cells. Our results showed that the more advanced is the state of the disease, the more the glycolytic pathway is compromised. Interestingly, Sertoli cells cultured under T conditions similar to those of type 2 diabetes mellitus stage are able to adopt alternative mechanisms that promote the use of alternative substrates, such as glycogen. At testicular level, it was evidenced that the pre-diabetic state induced by high-energy diets consumption also alters the glycolytic metabolism. Under these conditions, the glycolytic pathway is favored, given the increased expression and activity of essential proteins involved in this metabolic pathway. The expression of proteins associated with the production of lactate is also increased, which may have contributed to the increase in the testicular lactate content. However, and despite the metabolic adaptation observed, the reproductive parameters were affected, which may result from the favoring of a high oxidative environment. In fact, in those conditions, we observed a significant decrease in the expression of proteins involved not only in the maintenance of mitochondrial biogenesis, as in the activation of the reactive oxygen species defense system. The decreased testicular antioxidant potential, as well as the altered mitochondrial respiratory function contributed to a deficient bioenergetic capacity and augmented oxidative environment. In more advanced states of disease, as is the case of type 2 diabetes mellitus, testicular glycolytic metabolism was seriously compromised. Lactate dehydrogenase activity was severely diminished contributing to lower testicular content of lactate. Moreover, in those conditions there seems to be an adaptation of the testicular metabolism, reflected in the content of glycogen in the testes, which was increased. These results implied a testicular metabolic reprogramming under type 2 diabetes mellitus conditions, which promoted alternative metabolic pathways. However, the sperm parameters of the individuals with type 2 diabetes mellitus were seriously compromised, since motility and viability were substancially decreased and the number of sperm with abnormal morphology was increased. In conclusion, this study showed that metabolic diseases, particularly DM, contribute to a decrease in male reproductive potential by promoting profound alterations in testicular cellular metabolism, and particularly in the metabolism of Sertoli cells. Spermatogenesis is a complex process and the glycolytic metabolism is pivotal for the success of this cellular event. Glucose metabolism in Sertoli cells is targeted by numerous regulatory factors and both the initial and the advanced stages of DM the metabolism of glucose is altered in these cells. Furthermore, the more pronounced effects were observed in the most advanced stages of DM. In fact, we observed that, in the prodromal stage of DM, testicular metabolism tends to adapt in order to ensure an adequate production of lactate for developing germ cells. However, in more advanced stages of that disease, lactate production is seriously compromised. Moreover, these metabolic changes were associated with a decline in the reproductive parameters, that may lead to infertility, and that surely will be accountable for the decline in male reproductive health

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

Multivariable and distributed LQG control of a water delivery canal

This work addresses the problem of the development of a distributed LQG controller for a water delivery canal. The control structure proposed relies on a set o LQG control agents interconnected through a communication network. Each of these local control agents controls a canal reach made of a pool and the corresponding downstream gate and receives information (output signal and control moves) only from the corresponding canal reach and the ones that are adjacent to it. An algorithm is proposed to achieve coordinated action of the different local control agents. This distributed control structure is compared with centralized multivariable LQG control. Several aspects with incidence on performance are addressed, including the modification of the quadratic cost to ensure a constraint on closed-loop poles, the use of a nonlinear filter to limit noise effects and the impact of a quantization commonly forced in gate position. Experimental results obtained in a pilot canal are presented

Calibração e teste de modelos de controlo automático num canal de adução experimental

O artigo apresenta um canal automático, particularmente vocacionado para o estudo, experimentação e a demonstração de sistemas de controlo automático para canais e dos respectivos algoritmos. Faz-se uma apresentação sumária do controlo automático de canais e do sistema SCADA, instalado para a supervisão e controlo do canal automático. O artigo apresenta também uma aplicação do controlo local por jusante do tipo PI, desenvolvida para o canal automático e instalada no respectivo sistema SCADA. Foi desenvolvida uma interface multiplataforma para sistemas SCADA (IMSCADA). Esta interface permite testar, em contexto real, os modelos e algoritmos desenvolvidos de uma forma amigável, podendo os investigadores utilizar as suas ferramentas habituais de desenvolvimento, como pacotes de cálculo numérico ou linguagens de programação diversas. O artigo faz também a sua respectiva apresentação

KNOWLEDGE REPRESENTATION APPROACH TO CLOSED LOOP CONTROL SYSTEM - A TANK SYSTEM CASE-STUDY

Control engineering problems are dealt within a plethora of methods and approaches depending on the a priori knowledge, the description of the process to control, and the main control goal. Classical control theory is mainly based on properties of numerical models. This paper presents an approach that applies to a class of processes described by numerical and logical relations using inference and a knowledge base system. To attain this goal an ontology for control systems is constructed. The work presented in this paper is based in a three tank system benchmark

Actuator Fault Tolerant LQG Control of a Water Delivery Canal

The problem of reconfiguration of the control system to mitigate the effects of actuator faults in a water delivery canal is addressed in this paper. When a fault in an actuator is detected and isolated, the controller is reconfigured by changing the set of manipulated and process variables and using a different controller, associated to a different plant model, in a hybrid systems framework. In order to prevent instability that may be associated with switching among controllers, a dwell time condition is used. Both centralized and distributed control, a game approach is followed to coordinate the different local controllers. Experimental results are presented

Multi-Platform Controller Interface for SCADA Application

This paper concerns the development of a SCADA-Controller Interface (SCI) application for an open-channel experimental facility. Water delivery canals are complex and spatially distributed systems. The proposed application is to be applied to test control algorithms developed by several research groups with different technical approaches. The proposed interface allows the development of controllers in different environments - C/C++, MATLAB/Simulink and GNU Prolog - and may be easily extended to other environments. The experimental facilities with the used instrumented canal, the programmable logic controller (PLC) network and the SCADA system are also described in this paper. Finally, some software experimental results are presented