The Parametric Identification Of A Stationary Process

In the problems of identification it is supposed that the process has at least one measurable input size and at least one measurable output size. The identification of a process has three stages: the obtaining of a registration of process measurable sizes; the choice of a proper mathematical model for the process; the extract of the parameter values of the mathematical models from registered data. The parametric identification problem is an optimization problem, in which the best combination of values for the model parameters set is searched. In the paper is presented the parametric identification of a water flow process in a laboratory stand. The identification had the following dims: detailed understanding of how the stand works, finding a new illustrative experiment for the stand, the application of advanced techniques of automat control, and the development of a project of new stand, meant to allow a large variety of experiments

TAMIZAJE DE WEDELOLACTONA EN REPRESENTANTES PERUANOS DE ECLIPTINAE Y HELIANTHINAE (HELIANTHEAE, ASTERACEAE) Y MÉTODO PREPARATIVO APLICADO EN Eclipta prostrata (L.) L.

Se analiza varias especies de Ecliptinae y Helianthinae (Asteraceae) del Perú  en busca de wedelolactona, resultando ausente en todos los casos analizados, excepto en Eclipta prostrata (L.) L. una especie invasora común en muchos lugares de altitudes bajas en el Perú. El contenido de este compuesto fenólico en diferentes recolecciones de Eclipta prostrata muestra valores que van del 1.2 hasta el 2.7 por ciento. Consiguientemente se ha desarrollado método preparativo para wedelolactona a partir de Eclipta que permite obtener un producto de alta pureza pero con bajo porcentaje de recuperación respecto al contenido real.Palabras Clave: Ecliptinae, Eclipta prostrata, wedelolactona, cromatografía.ABSTRACTSeveral species of Ecliptinae and Helianthinae (Asteraceae) from Peru are analyzed in search of wedelolactone, being absent in all the analyzed cases, except in Eclipta prostrata (L.) L. a common weed in many low places of Peru. The content of this phenolic compound in different collections of Eclipta prostrata shows values ranging from 1.2 to 2.7 percent. Accordingly, a preparative method has been developed for wedelolactone from Eclipta, which allows to obtain a high purity product but with a low percentage of recovery from the actual content.Keywords: Ecliptinae, Eclipta prostrata, wedelolactone, chromatography

A Diferent Approach In The Parameters' Identification Of A JFET Using Genetic Algorithms

The genetic algorithms are developing in three directions: the genetic algorithms theory, the genetic algorithms programming and the study of the problems that can be solved with genetic algorithms. In this paper it is presented a study on the identification of the parameters of a JFET (Junction Field Effect Transistor). The problem is very exciting because the JFET has two mathematical models: an empirical one, and an analytic one, both of the models being nonlinear in parameters. In a parametric identification problem, it is minimized the distance between an experimental data set and an analytical function, which represent the mathematical model of the studied phenomenon. Basically, a genetic algorithm can maximize a fitness function, which is a positive defined function whose maximum is searched. However, genetic algorithms can also solve minimum problems, on condition that to the minimum problem can be applied an algebraic transform or a rank based transform in a maximum problem

A New Method Of Gene Coding For A Genetic Algorithm Designed For Parametric Optimization

In a parametric optimization problem the genes code the real parameters of the fitness function. There are two coding techniques known under the names of: binary coded genes and real coded genes. The comparison between these two is a controversial subject since the first papers about parametric optimization have appeared. An objective analysis regarding the advantages and disadvantages of the two coding techniques is difficult to be done while different format information is compared. The present paper suggests a gene coding technique that uses the same format for both binary coded genes and for the real coded genes. After unifying the real parameters representation, the next criterion is going to be applied: the differences between the two techniques are statistically measured by the effect of the genetic operators over some random generated fellows

FACTORS INFLUENCING THE DEFICIT OF SOCIAL SECURITY SYSTEMS

This paper analyses a number of factors that affect the deficit of social security funds. For the statistical analysis, we used a data panel covering ten countries in Central and Eastern Europe. The variables analysed were: migration, unemployment and dependency ratio of the elderly. All states analysed are characterised by a similar pattern in terms of social security systems’ configuration. The pension system, as basic component of the social security system, is of the PAYG type, being vulnerable to demographic changes.Also, all these countries have experienced the transition from socialist to the capitalist system, facing socio-economic and demographic problems such as unemployment, migration or population aging. The results show that all thesefactors influence the volume of the deficit of social security funds