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Copyright of Formación Universitaria is the property of Centro de Informacion Tecnologica (CIT) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Góndola, Enseñanza y Aprendizaje de las Ciencias is the property of Gondola, Ensenanza y Aprendizaje de las Ciencias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Uni-Pluri/Versidad is the property of Universidad de Antioquia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Social Review (2695-9755) is the property of Eagora Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present research study aims to develop a novel methodology for estimating the VKT (Vehicle Kilometers Traveled) indicator and the energy consumption according to road transport type. Calculations are made for the Province of Loja (Ecuador) for the year 2014 by using an OLADE (Latin American Energy Organization) energy balance method. This is combined with a model similar to the Hardy Cross hydraulic flow systems solution with linear equations. The transportation system is represented as an energy balance and the inputs are: total fleet and vehicle type, specific average consumption for each vehicle type, and global fuel sales. The results show that there is a 2% variation between calculated consumed energy and total dispatched energy. The total energy used is 1,123,198 BEP, of which 24.65% is for passenger transport and 66.18% for cargo transport. It is concluded that the proposed methodology is appropriate, applicable nation-wide, and replicable in other provinces. [ABSTRACT FROM AUTHOR]

Copyright of Formación Universitaria is the property of Centro de Informacion Tecnologica (CIT) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Nicolaita de Estudios Económicos is the property of Universidad Michoacana de San Nicolas de Hidalgo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tennessee Eastman plant (TEP) involves very complex process with presence of non linearity, for that it is necessary the control of important variables. In this paper a TEP model is developed. Gray box models are selected to model the process. Gray box models have advantages with respect to classic model techniques, these techniques are knowledge models and empirical models. First, models are obtained employing mass and energy balances, defining parameters and making supposed. Then, from process data and employing MatLab® software, empirical models are obtained. The combination of all models constitutes the gray box final model and the general objective of this paper. [ABSTRACT FROM AUTHOR]

In this paper, an iterative algorithm is constructed to improve the solution of a system of linear equations, of the form Ax = b, when it is solved using the Gauss-Jordan method and by using finite arithmetic. Understanding the functioning of the algorithm, showing its scope and analyzing how it is deduced, is achieved through the concept of matrix norm, together with some of its properties. The concept of the condition number of a matrix is introduced, and are found bounds for it by using the matrix norms. Finally, it is explained the iterative algorithm of the Refinement, showing the power of this one, when it is solved a system of linear equations ill conditioned. [ABSTRACT FROM AUTHOR]

The objective of the article is to present a proposal for the restructuring of the interurban transportation system of travellers by road in Aragón, based on a previous diagnosis. Several sources of information and spatial analysis methods are used. The difficulty of providing a quality transport service in regions of low population density and settlements dispersion is noted and the inefficiencies of the current system of linear concessions are identified. A new system of zonal concessions is proposed, which allows for greater coordination and integrates general and school transportation. The proposal is valued economically and compared with the plans of the regional administration. [ABSTRACT FROM AUTHOR]

Objective. Determine the progeny difference expected (DEP) for the weaning weight adjusted to 205 days (PD) in crossbreed Brahman females born in 2016 as selection criteria for future breeders. Materials and methods. It is analyzed 3467 records generated between 1983 and 2016 in the Napo farm (San Vicente, Manabí, Ecuador). The statistical model included the random effect of the father and as fixed effects: breed composition, sex and year of birth. The variance analysis was performed using the GLM procedure of the SAS statistical package. The components of the variance between and within the father to calculate the heritability (h²) of the PD and the breeding values, the MTDFRELM software was used, applying the animal model, through the evaluation system of the Best Linear Unbiased Predictor (BLUP). Results. It was found that the PD average for the 349 females born in 2016 was 173.67±34.23 kg. A highly significant difference (p=0.01) was found for the random and fixed effects. The h² for PD was 0.13±0.04. The DEP fluctuated between -6.13 and +5.58 kg with a range between the breeding values of 11.71 kg and an accuracy between 0.50 and 0.72. Conclusion. The low h² found for PD shows the high influence of non-genetic factors; it is necessary to identify the best crossbreed that adapts to the livestock in order to obtain high performance products in the PD. [ABSTRACT FROM AUTHOR]

The article lists doctoral theses of mathematics that were presented in Spain in year 2018 on several topics including light field distribution within Synechocystis Sp. Pcc 6803 culture, linear systems and random differential equations.

Copyright of Revista Tecno Lógicas is the property of Instituto Tecnologico Metropolitano and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To be able to resolve tomographic inversion problems in travel time, it is necessary the construction of distance matrices containing information of survey array geometry, the discretized domain shape and the distance traveled by rays in each area elements that compose it. Domain considered are generally rectangular for ease of geometric resolution. In this work is circular due to the need to carry out investigation in columns of this shape. Distance matrices are used to solve the linear system, which leads to the determination of velocity values in each element of the domain. Taking in mind discretization, there are several possibilities for the construction of arrays of pixels: may those be defined in one quadrant and obtaining the rest by symmetry; build arrays using any size pixels independent of the quadrant, and finally construct distance matrices with square pixels. Each option will provide access to new research possibilities. In this work an original procedure was developed for the construction of matrices with elements of the last type. The procedure was validated with simulated data using the damped least squares solution (DLSS) method, which demonstrated the efficiency of the algorithm. [ABSTRACT FROM AUTHOR]

When you want to show if there is a statistical association or differences between categorical variables, it is recommended to use the Χ² test. This nonparametric test is one of the most used in clinical research; it contrasts nominal or ordinal qualitative variables that are observed in clinical practice. This test calculates the p value that determines whether differences between groups are real or due to chance. The Χ² test is the basis other tests to analyze qualitative ordinal variables as Χ² for linear trend, which compares three groups with two outcomes or McNemar test which contrasts two related samples (a before and afterward comparison) or Mantel-Haenszel Χ², which controls for potential confounding variables. When using small samples, where the expected is less than 5, Fisher's exact test should be used. These tests are the most widely used in the medical literature, however, do not give us the magnitude or the direction of the event and a proper interpretation that requires clinical judgment is needed. [ABSTRACT FROM AUTHOR]

The influence of training structure on the formation of equivalence relations and equivalence-equivalence relations was assessed. Three groups learned conditional relations using different training structures: Many to One, One to Many and Linear Series. The results showed a training structure effect on the percentage of correct responses in the equivalence relations test. However, this effect was not observed on the test of equivalence-equivalence relations. These results show that training structure has effects on the formation of equivalence relations, but it has no influence on equivalence-equivalence relations. These findings are analyzed according to the requirements for the formation of equivalence-equivalence relations. [ABSTRACT FROM AUTHOR]

This paper describes a solution method to the problem of processing n jobs on m non-related parallel machines. It is a linear and combinatorial generalized allocation problem that considered a sequencedependent setup time and dynamic job entry. A genetic algorithm with integer coding and random generation of population, parent selection, crossover and mutation is proposed. There are two descendants per generation that are compared against the worst existing element to enter to population. After a number of generations that is proportional to the product of nxm the solution is generated. The jobs are sequenced on each machine by due date and computational times are acceptable. It is concluded that the proposed genetic algorithm is an effective and efficient solution that focuses on reducing processing time and on meeting deadlines. [ABSTRACT FROM AUTHOR]

Copyright of Revista Cubana de Ciencias Informáticas is the property of Universidad de las Ciencias Informaticas (UCI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Cubana de Ciencias Informáticas is the property of Universidad de las Ciencias Informaticas (UCI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Enl@ce: Revista Venezolana de Información, Tecnología y Conocimiento is the property of Universidad del Zulia, Laboratorio de Investigacion y Sistemas de Informacion and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study describes two iterative structural analysis procedures under a linear system within a first-order theory that permits the approximate and exact study of flat frames and space frames with independent displacements without having to solve any system of equations. The approximate system provides sufficiently accurate results in few iterations, and the error can be estimated at any time. The exact procedure uses two simple, practical application tables that can be manually implemented in software. The tables provide deformed meshes with fewer operations than those required by matrix algebra. [ABSTRACT FROM AUTHOR]

Positive systems are systems in which the state variables are always positive or non negative in value. In this review paper, we describe such systems through the establishment of its main structural properties and the exposure of some of its applications. [ABSTRACT FROM AUTHOR]

Within this report we are describing the treatment made to the Gross-Pittaevsky equation, which describes the behavior of Bose-Einstien condensates, in order to be normalized and nondimensionalized. We show that the condensate solutions are those normalized functions for which the energy functional minimices. In order to solve the problem the equation is discretized by means of a gradient flow (GFDN) which, under certain circumstances, is energy diminishing and therefore appropriate to find ground and first excited states under proper initial conditions. To discretize completely the GFDN two algorithms known as Backward Euler sine-pseudospectral method (BESP) and Backward/Forward Euler sine-pseudospectral method (BFSP) are proposed. In the framework of this methods the spacial derivatives of the wave function can be written in terms of sine transforms which make easier the solution of the linear system appearing when the iteration is carried out. Finally we report the results obtained by the simulations of condensates and we find some properties of the dependence of the wave function and its response to different potentials with respect to the condensate interaction parameter. [ABSTRACT FROM AUTHOR]

Copyright of Revista Cubana de Ciencias Informáticas is the property of Universidad de las Ciencias Informaticas (UCI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)