87 research outputs found
Dinámica de la inflación: Un análisis econométrico del ajuste heterodoxo mexicano
This paper examines the recent inflationary process in the Mexican economy using two complementary approaches that avoid (some-what) the restrictions imposed by structural models. The first approach applies a vector autoagresive process, while the second applies multivariate cointegration.
Reliable fault-tolerant model predictive control of drinking water transport networks
This paper proposes a reliable fault-tolerant model predictive control applied to drinking water transport networks. After a fault has occurred, the predictive controller should be redesigned to cope with the fault effect. Before starting to apply the fault-tolerant control strategy, it should be evaluated whether the predictive controller will be able to continue operating after the fault appearance. This is done by means of a structural analysis to determine loss of controllability after the fault complemented with feasibility analysis of the optimization problem related to the predictive controller design, so as to consider the fault effect in actuator constraints. Moreover, by evaluating the admissibility of the different actuator-fault configurations, critical actuators regarding fault tolerance can be identified considering structural, feasibility, performance and reliability analyses. On the other hand, the proposed approach allows a degradation analysis of the system to be performed. As a result of these analyses, the predictive controller design can be modified by adapting constraints such that the best achievable performance with some pre-established level of reliability will be achieved. The proposed approach is tested on the Barcelona drinking water transport network.Postprint (author's final draft
Fear of the unknown: Inlfuenza vaccination
Influenza is a major cause of morbidity and mortality; current estimates by the World Health Organization (WHO) are 3 to 5 million cases and 250,000 to 500,000 deaths worldwide every year. Most deaths associated with it occur among people age 65 or older, as well as among persons suffering a chronic debilitating disease regardless of age. The recent 2009 pandemic served to foster interest in this disease. An inactivated virus vaccine has been available since the late 1940´s but it only began to be used extensively when the influenza virus antigenic variability was taken into account.
Aside from such variability, influenza viruses are capable of infecting a wide variety of vertebrates, including many avian species, both wild and domestic, thus it is essential to monitor the antigenic characteristics of influenza virus strains currently circulating, and so the vaccine formula has
to be evaluated and modiied accordingly every yea
Model-based Fault-tolerant Control to Guarantee the Performance of a Hybrid Wind-Diesel Power System in a Microgrid Configuration
AbstractThis paper presents a comparison of two different adaptive control schemes for improving the performance of a hybrid wind-diesel power system in an islanded microgrid configuration against the baseline controller, IEEE type 1 automatic voltage regulator (AVR). The first scheme uses a model reference adaptive controller (MRAC) with a proportional-integral-derivative (PID) controller tuned by a genetic algorithm (GA) to control the speed of the diesel engine (DE) for regulating the frequency of the power system and uses a classical MRAC for controlling the voltage amplitude of the synchronous machine (SM). The second scheme uses a MRAC with a PID controller tuned by a GA to control the speed of the DE, and a MRAC with an artificial neural network (ANN) and a PID controller tuned by a GA for controlling the voltage amplitude of the SM. Different operating conditions of the microgrid and fault scenarios in the diesel engine generator (DEG) were tested: 1) decrease in the performance of the diesel engine actuator (40% and 80%), 2) sudden connection of 0.5 MW load, and 3) a 3-phase fault with duration of 0.5seconds. Dynamic models of the microgrid components are presented in detail and the proposed microgrid and its fault-tolerant control (FTC) are implemented and tested in the Simpower Systems of MATLAB/Simulink® simulation environment. The simulation results showed that the use of ANNs in combination with model-based adaptive controllers improves the FTC system performance in comparison with the baseline controller
Leak signature space: an original representation for robust leak location in water distribution networks
In this paper, an original model-based scheme for leak location using pressure sensors in water distribution networks is introduced. The proposed approach is based on a new representation called the Leak Signature Space (LSS) that associates a specific signature to each leak location being minimally affected by leak magnitude. The LSS considers a linear model approximation of the relation between pressure residuals and leaks that is projected onto a selected hyperplane. This new approach allows to infer the location of a given leak by comparing the position of its signature with other leak signatures. Moreover, two ways of improving the method's robustness are proposed. First, by associating a domain of influence to each signature and second, through a time horizon analysis. The efficiency of the method is highlighted by means of a real network using several scenarios involving different number of sensors and considering the presence of noise in the measurements.Postprint (published version
Novel Therapies in Clinical Development for Advanced Disease
Recent advances in melanoma treatment have supposed a dramatic transformation overcoming the situation that was faced 15 years ago, when advanced melanoma was a fatal disease, with less than five percent of patients being alive after 1 year of diagnosis. However, in spite of the impressive improvement that has been achieved with immunotherapies and targeted therapies that are completely part of the standard landscape for treatment, additional therapeutic advances are still needed. In this chapter, we review those systemic and local treatments which are undergoing clinical development, explaining their mechanisms of action and the already presented either preliminary or final results, most of them in terms of response rate
Robust nonlinear trajectory controllers for a single-rotor UAV with particle swarm optimization tuning
This paper presents the utilization of robust nonlinear control schemes for a single-rotor unmanned aerial vehicle (SR-UAV) mathematical model. The nonlinear dynamics of the vehicle are modeled according to the translational and rotational motions. The general structure is based on a translation controller connected in cascade with a P-PI attitude controller. Three different control approaches (classical PID, Super Twisting, and Adaptive Sliding Mode) are compared for the translation control. The parameters of such controllers are hard to tune by using a trial-and-error procedure, so we use an automated tuning procedure based on the Particle Swarm Optimization (PSO) method. The controllers were simulated in scenarios with wind gust disturbances, and a performance comparison was made between the different controllers with and without optimized gains. The results show a significant improvement in the performance of the PSO-tuned controllers.Peer ReviewedPostprint (published version
Sensor placement for leak location in water distribution networks using the leak signature space
In this paper, a sensor placement approach to improve the leak location in water distribution networks is proposed. The sensor placement problem is formulated as an integer optimization problem where the criterion to minimize is the number of overlapping signature
domains computed from the leak signature space (LSS) representation. A stochastic optimization process is proposed to solve this problem, based on either a Genetic Algorithms (GA) or a Particle Swarm Optimization (PSO) approach. Experiments on two different DMAs are used to evaluate the performance of the resolution methods as well as the effciency achieved in the leak location when using the sensor placement results.Postprint (published version
Optimization of the Distribution and Localization of Wireless Sensor Networks Based on Differential Evolution Approach
Location information for wireless sensor nodes is needed in most of the routing protocols for distributed sensor networks to determine the distance between two particular nodes in order to estimate the energy consumption. Differential evolution obtains a suboptimal solution based on three features included in the objective function: area, energy, and redundancy. The use of obstacles is considered to check how these barriers affect the behavior of the whole solution. The obstacles are considered like new restrictions aside of the typical restrictions of area boundaries and the overlap minimization. At each generation, the best element is tested to check whether the node distribution is able to create a minimum spanning tree and then to arrange the nodes using the smallest distance from the initial position to the suboptimal end position based on the Hungarian algorithm. This work presents results for different scenarios delimited by walls and testing whether it is possible to obtain a suboptimal solution with inner obstacles. Also, a case with an area delimited by a star shape is presented showing that the algorithm is able to fill the whole area, even if such area is delimited for the peaks of the star
El uso de las Fintech por la Generación Millenial en México
The Fintech sector in Mexico has gained great relevance, this sector has shown an important 14% growth during 2019, with 660 companies and the generation of 60,000 job positions. This research aims to analyze the adoption of Fintech by the Millennials generation in the State of San Luis Potosí, Mexico. A convenience sample of 90 people was composed, their age range is between 20 and 50 years. A 30 question instrument related to the knowledge, use and management of Fintech was applied. The study is exploratory and a quantitative-correlational approach is adopted. The results show that Millennials adopt these technologies to a greater extent; one of the determining factors being the affordable cost compared to traditional banking. Respondents exhibit a preference for technological platforms to carry out their financial operations, instead of going to a bank branch.El sector Fintech en México ha cobrado gran relevancia, y muestra de ello ha sido su crecimiento del 14% durante 2019, con 441 empresas y la generación de 60,000 empleos. El objetivo de esta investigación es analizar la adopción de las Fintech por la generación Millenial en el Estado de San Luis Potosí, México. Se conformó una muestra seleccionada a conveniencia de 90 personas, cuyo rango de edad se encuentra entre los 20 y 50 años, y a la cual se le aplicó un instrumento de 30 preguntas relacionadas al conocimiento, uso y manejo de las Fintech. El trabajo es de carácter exploratorio y se adopta un enfoque cuantitativo-correlacional. Los resultados ponen de manifiesto que los Millenials adoptan en mayor medida estas tecnologías, siendo uno de los factores determinantes el costo asequible que ofrecen en comparación con la banca tradicional. Los encuestados manifestaron una preferencia para realizar sus transacciones financieras por medio de plataformas tecnológicas, en lugar de acudir a una sucursal
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