Optimal Shedding Against Voltage Collapse Based on Genetic Algorithm

The prevalent tendency in power transmission systems is to operate closer and closer to the energy limit, rendering system voltage instability a commonly widespread phenomenon. It is, therefore, necessary that certain remedial corrective controls need be undertaken whenever these systems tend towards failure. In this respect, load shedding stands as a major correction mechanism and such a failure can be prevented and nominal system voltage can be resumed. It is worth noting however that load shedding must be implemented very carefully to ensure the satisfaction of both the customer and the electricity-production company. In this context, our focus of interest is laid on load and machine shedding against voltage collapse as an effective corrective method. It is important to note that such a problem turns out to be commonly defined as an optimization problem under constraints. Using genetic algorithms as resolution methods, the application of the proposed methods was implemented on the 14-node IEEE test network, while considering a number of different case studies.

Mixture density network estimation of continuous variable maximum likelihood using discrete training samples

Mixture density networks (MDNs) can be used to generate posterior density functions of model parameters $$\varvec{\theta }$$ θ given a set of observables $${\mathbf {x}}$$ x . In some applications, training data are available only for discrete values of a continuous parameter $$\varvec{\theta }$$ θ . In such situations, a number of performance-limiting issues arise which can result in biased estimates. We demonstrate the usage of MDNs for parameter estimation, discuss the origins of the biases, and propose a corrective method for each issue.

Actitudes y expectativas respecto a la paternidad y maternidad de los estudiantes de medicina de la Universidad Nacional Jorge Basadre Grohmann de Tacna, 2018

Objetivo: Determinar las actitudes y expectativas respecto a la maternidad o paternidad del estudiante de medicina de una universidad pública de Tacna. Material y métodos: Estudio descriptivo en 253 estudiantes del 1.º al 6.º año de la Escuela de Medicina Humana de la Universidad Nacional Jorge Basadre Grohmann de Tacna. Semilleros del 6.º año aplicaron encuesta anónima de opción múltiple, con consentimiento informado, en noviembre de 2018, con mentoría del docente del curso de Pediatría III. El procesamiento y análisis de datos se realizó con el programa SPSS v.23. Resultados: El 49.2 % de las mujeres sería madre de los 30 a 35 años; el 47.1 % tendría 2 hijos. De los varones, el 41.5 % sería padre de los 30 a 35 años; el 50 % tendría 2 hijos, y el 53.4 % le gustaría que el primer hijo fuera niño. Respecto al trabajo; el 76.1 % de las mujeres no tomarían doble horario para el sustento de su familia, y el 62 % contrataría una empleada; pero el 52.1 % de los varones sí tomaría doble horario de trabajo. No confían en cunas y jardines: un 67.6 % de mujeres y un 68.5 % de varones. Respecto a actitudes frente al matrimonio; el 62 % de mujeres y 67 % de varones se casaría por civil e iglesia, y solo el 18 % de mujeres y 16 % de varones no se casaría. Además; el 62 % de mujeres no se ligaría las trompas, y el 71 % considera que el ser “ama de casa” es igual de satisfactorio que trabajar por un sueldo; el 32 % de los varones no se haría la vasectomía, y el 74 % no usaría el castigo físico como método correctivo para sus hijos. Conclusión: Los estudiantes de medicina de la Universidad Nacional Jorge Basadre Grohmann pospondrían la maternidad o paternidad a edades superiores a 30 años, y limitaría el tamaño de su familia. Ambos sexos aún mantienen ideas conservadoras respecto al matrimonio, y las mujeres conservan la idea de ser amas de casa, además de su profesión. Results: 49.2 % of women, would be a mother at 30 to 35 ear old, 47.1 % would have 2 children. Of the men, 41.5 % would be a father at 30 to 35 year old, 50 % would have 2 children and 53.4 % would like the first child to be a boy. Regarding work, 76.1 % of women would not take double shifts at work to support their family and 62 % would hire an employee; but 52.1 % of the men would take double shifts at works. 67.6 % of women and 68.5 % of men do not trust cribs and gardens. Regarding attitudes towards marriage, 62 % of women and 67 % of men would marry by civil and church and only 18 % of women and 16 % of men would not marry. In addition, 62 % of women would not have their tubes tied and 71 % consider that being a homemaker is just as satisfying as working for a salary; 32 % of the men would not have a vasectomy and 74 % would not use physical punishment as a corrective method for their children.

Simulation of Chaotic Oscillators of Fractional Order

In 1695 the theory of fractional calculus was introduced, but it only developed as a pure mathematical branch. Currently several research groups have focused on the control, the implementation of filters, PID controllers, synchronization, the implementation of circuits of chaotic systems of fractional order, etc. Currently, the number of applications of fractional calculus is increasing rapidly, these mathematical phenomena have allowed us to describe and model a real object more accurately than the classical "integer" methods. Along with the development of the fractional calculation, it was shown that many fractional-order nonlinear dynamic systems behave in a chaotic manner. This is the type of non-linear systems that are addressed in this research topic with the focus on derivatives of arbitrary order, where numerical simulations of chaotic behavior are presented in non-linear, fractional-order autonomous models. The case studies are six chaotic oscillators of fractional order; The systems of Lorenz, Rӧssler, Financiero, Lui, Chen and Lü, whose attractors are obtained by applying the definitions of the Grünwald-Letnikov definitions and the predictive corrective method of Adams-Bashforth-Moulton.

The cognitive impairments and their correction for children with cerebral palsy by intensive neurophysiological rehabilitation system

The aim of the study was to examine the dynamics of cognitive impairments in children and teenagers with cerebral palsy during rehabilitation using Intensive neurophysiological rehabilitation system (INRS). To evaluate the eff ectiveness of cognitive impairments by INRS 174 patients with cerebral palsy were examined, before and after completion of rehabilitation. Main positive eff ects of using INRS for correction of cognitive impairment in children with cerebral palsy consisted in improving the functions of verbal memory, voluntary attention, neurodynamic and operational components of mental operations, improving performance of verbal and nonverbal intelligence. Proven that intensive neurophysiological rehabilitation system is an eff ective corrective method of cognitive impairments in children with cerebral palsy. Key words: cerebral palsy, cognitive impairments, rehabilitation, intensive neurophysiological rehabilitation system.

ANALYZE MACHINE MAINTENANCE COST WITH CORRECTIVE METHOD AND PREVENTIVE METHOD TO INCREASE PRODUCTION RESULT

The object of research is the engine maintenance system that is on the CV. Fajar Offset. The production process is often disrupted by the high amount of damage, which results in maintenance costs. Machines that often experience damage affect the printed product to be produced. The amount of downtime will affect the profits that will have an effect on the swollen maintenance costs of the budget that has been prepared. The purpose of this study is to analyze the cost of machine maintenance with corrective method and preventive method against increase production result. The results showed that machine maintenance was done by corrective method and preventive method proven to have an effect on increase production result.