no. 15 (2016)

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    Algoritmo genético para sintonización de pid basado en la integral del error absoluto
    (Universidad de Cuenca, 2018-05) Pillajo, Carlos; Bonilla, Paul; Hincapié, Roberto
    Despite the rapid development in systems of process control, the PID controller (Proportional-Integral-Derivative) is the most widely used in the industry, because its simple and robust features are enough to work in a variety of processes. However, it is properly tuned complex gains PID, because the processes are nonlinear systems, or stationary, so that its characteristics change over time. The tuning process is not trivial, since it largely depends on the process to be controlled, and there is no method that is appropriate for all applications. Given this adaptive control systems, where the controller performs a self-tuning arise. Are designed very sophisticated about classical PID strategies, these techniques have artificial intelligence. In this paper a genetic algorithm capable of tuning PID controllers based on the criterion of the integral absolute error (IAE), the algorithm is simulated and compared with matlab tools designed for this purpose..
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    Análisis de la composición corporal en estudiantes de la Carrera de Cultura Física de la Universidad de Cuenca 2015
    (Universidad de Cuenca, 2016-05) Brito, Vicente; Contreras, Teodoro; Barreto, Jorge
    The purpose of this study was to define the anthropometric profile and parameters related to body composition of a group of university students. The methodology / standards proposed by Carter and Faulkner and approved by the International Society for the Advancement of the kineanthropometry (ISAK) were performed as basic anthropometric examination. In total 12 anthropometric variables were considered weight, height, 5-fold (subscapularis, triceps, abdominal, suprailiac, medial leg), 3 diameters (radial biestiloideo, biepicondylar of the humerus and femur biepicondylar) and 2 perimeters (contracted medial arm and leg). The results for males were: Age 23.05 ±4.07 years; Weight 72.88 ±7.20 kg; Size 168.02 ±6.67 cm, and with an Ideal Weight of 63.22 ±7.41 kg; and the results for women were: Age 23.82 ±3.17 years; Weight 57.95 ±8.61 kg; and Size 158.09 ±7.51 cm, Ideal Weight of 54.30 ±7.59. It can be concluded that the somatotype predominant among males was the endo-mesomorphic with median values of Endomorphic =3.16, mesomorphic= 5.03 and for ectomorphic =2.17, while among women the meso endomorphic was the predominan type with values of 5.04 for endomorphic, 4.50 for mesomorphic and 1.51 for ectomorphic.
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    Comparación de modelos termodinámicos en el análisis topológico de mezclas
    (Universidad de Cuenca, 2016-05) Forero, Héctor; Caballero, Ashley; García, Blanca; Castro, Agustín; Gómez, Alvaro; Pisarenko, Yuri; Cardona, Carlos
    The objective of this paper is to introduce and propose a thermodynamic model appropriate for predicting the properties of the propanoate methyl – propionic acid – methanol – water mixture, resulting from the esterification of propionic acid. For this purpose, a topological analysis is carried out from phase equilibrium calculation and azeotropy evaluation, considering three thermodynamic models and mixing rules (PCSAFT, PRWS and PSRK). Based on the performed analysis, it was found that the predictive model Soave Redlich Kwong, is the most appropriate for the studied mixture since it predicts the azeotropes that are reported in practice. In addition, the conceptual analysis of the trajectories of process shown in the residue curves was performed and a process trajectory for obtaining the products in a distillation tower according to the required design considerations was established.
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    Factores de riesgo asociados a alergia alimentaria: una revisión de estudios en niños y adolescentes
    (Universidad de Cuenca, 2016-05) García, Ana; Córdova, Diana; Zuñiga, Gabriela
    Abstract: Food allergy is an adverse reaction caused by immunological mechanisms that affects most often to 5% of children and 3% - 4% of adults. In the scientific literature have been implicated genetic, socio-demographic, pre and post-natal, nutritional and environmental risk factors reporting variable and inconsistent results. In this context, this article makes a literature review about probable factors associated with the development of food allergy, for which we considered those publications from maximum 10 years ago, which helps to clarify the findings until now. According to this review, factors such as heredity of atopy, atopic diseases, age, gender, maternal age and exposure to cigarette were considered as high association to the development of food allergy because there is a wide and consistent association in several studies. While factors such as ethnicity, socioeconomic status, gestational age, type of delivery, birth weight, breastfeeding, age of introduction of solid foods, vitamin D intake in maternal diet, type of formula, contact with animals, day care attendance, number of older brothers and geographical areas have been considered as low association since research shows to be inconsistent or isolated.
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    Simulación de los procesos psicrométricos
    (Universidad de Cuenca, 2016-05) Cardoso, Gustavo; Puzhi, Milton; Zhinín, Saúl
    The physical processes of water evaporation and condensation and the corresponding reverse processes, establish mechanisms of addition and/or removal of moisture, causing changes in different ecological, housing and industrial systems. Multiple air conditioning processes are needed in the industry, these have been modeled mathematically as unit operations of humidification, dehumidification and drying, in turn, they depend on several psychrometric parameters such as temperature, relative humidity, absolute humidity, pressure, etc. Its calculation by equations is more or less complex; graphic solutions are more convenient, but less precise; software and simulation packages in psychrometry are scarce. This paper develops the creation of a computerized model based on an algorithmic tool that can reduce complexity and improve the accuracy of these calculations, useful both for industrial and teaching applications. This software is based on the ®Java language to simulate cases and calculation methods of humidification, dehumidification, drying and mixtures of air based on psychrometric equations. The software can be used for a wide range of temperatures and at different altitudes above sea level. The validation of the model has been performed in Ecuador´s environmental conditions. Results showed good correlation between the results obtained via manual computation and those obtained using the model.