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This paper presents the current reasons for getting involved in the math class of an eleventh-grade student who states that she has never liked math classes in her previous years. For this reason, it is developed a contextualization e of the student, analyzing and reporting what happened with the math class and her stance when this person is invited to develop a mathematical modeling environment from the socio-critical perspective. This document is part of the results obtained in the master's thesis, which adopts a critical research methodology and an analysis of the discourses of the students who were involved in the created environment. The results found that students have a variety of reasons for getting involved in the math class, in which future, context and intentions of the students are important. [ABSTRACT FROM AUTHOR]

This paper shows that economic theory can be analyzed by means of system dynamics, an intuitive approach that makes it possible to represent graphically the feedback loops between the variables involved in the models. It models Adam Smith's view of growth, according to Robert Heilbroner's highly simplified interpretation, (developed in a more comprehensive and exhaustive way by his teacher, the German sociologist and economist Adolph Lowe) by proposing a computational system for the study of complex models. The paper does not intend to make an original contribution to economic modeling, but to show a tool that allows simulations based on the principles of system dynamics, using specialized software. This tool can be used in teaching to show alternative modeling options to the conventional ones. [ABSTRACT FROM AUTHOR]

Humanity has suffered throughout its history from different types of pandemics caused by deadly infectious diseases. Mathematical models are very useful tools to understand the dynamics of the behavior and propagation of these. Among these models are those known as SIS, SIR and SEIR. This paper presents a brief explanation of the structure of these models and its use in some pandemics. In particular, some SIR-type models without and with delays are analyzed with special interest, as well as their applications to the current pandemic caused by the SARS-CoV-2 virus. To determine the correspondence between some of the models analyzed and the data of Infectious and Recovered from Mexico reported by the World Health Organization (WHO), simulations are presented in three different time periods between the years 2020-2021. In addition, an unpublished SIR-type mathematical model with three delays is proposed as a main contribution. Finally, a discussion is given on the application of numerical algorithms to identify some parameters of mathematical models, such as ordinary least squares. [ABSTRACT FROM AUTHOR]

Multihead weighing processes are considered an important strategy in packaging companies. Multihead weighers are used for dosing a wide range of products, from granules to large products. The packaging process consists of choosing a subset of hoppers in the multihead weigher to form a product package. This paper proposes a set of filling strategies of hoppers to reduce the variability in the weight of the produced packages. The strategies are evaluated through a bi-objective optimization approach which aims to minimize the absolute difference between the target weight and the actual weight of the packages, while trying to maximize the selection of those hoppers with more time in the packaging system. In the bi-objective approach, the considered objectives are dynamically adjusted and managed in each packaging operation. In addition, the mathematical model and the packing algorithm are developed and presented. The results of the process performance parameters are obtained and analyzed to show the effectiveness of the proposed strategies. Also, conditions of minimum variability are identified and those can be used by the packaging industry where multihead weighers are used. [ABSTRACT FROM AUTHOR]

The International Center for Settlement of Investment Disputes (ICSID) is an organization based in Washington, United States belonging to the World Bank, whose objective is the support to resolve conflicts between States. Three South American countries, Bolivia, Ecuador and Venezuela, at certain times have decided to leave this organism. This paper aims to determine the best strategy to follow for these countries to make the most convenient decision about to leave or not this organization. The solution of this problem is done by applying neutrosophic games. Game Theory is used to solve conflict situations among different parties. In this paper, neutrosophic games are non-cooperative, in normal form, two players and zero sum games. In addition, evaluations are carried out with linguistic terms associated with neutrosophic sets, where indeterminacy is part of the calculations and this is the reason for including neutrosophic sets in modeling this problem. Obviously, in a dispute there is uncertainty and also lack of information, contradictions among the parties, inconsistencies, and other phenomena which justify the use of neutrosophy. [ABSTRACT FROM AUTHOR]

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]

This paper shows up a work developed in the county of Benguela, Republic of Angola. As case matter, it was considering the Statistical Applied discipline that it is imparting in ISCED of Benguela. To determine the present state of their empiric teachinglearning process (interviews, pedagogic tests) and statistical methods they used. This paper pretend to show how to carry out the quantitative study, applying statistical tools one variable and multivariate as the Analysis of Main Components for Categorical Data, which allowed to verify the indicators (variables) that more weight had in the valuations emitted by the students in the instruments. [ABSTRACT FROM AUTHOR]

Background. One of the reasons to study infectious diseases is to increase their control and eradication. Mathematical models could be a powerful tool to achieve that end, which allows for optimization of limited resources, and conduct more effective measures; these models are made to predict and increase understanding of the studied phenomenon. The aim of this paper is to conduct simulations using the stochastic model known as Susceptible, Infected, Recovered (SIR), and introduce them in the curricula of students, epizootiological analyses, and decision-making. Methods. Virtually the entrance of ten migrating birds with respiratory processes was simulated on bird rearing farms averaging 5000 free-range poultry from different types. The R0 was determined depending on the incidence. Results. Simulation was run with a low communicability index (1.8 %), that is, 1.8 out of every 100 birds get sick, after interacting with other 5 birds each, at random, for 10 days. In the absence of intervention, there would be a spike of sick animals at 20 days, surpassing 3000 birds. A basic reproductive number greater than the unit (R0=1.14) was observed, thus qualifying as an epidemic outbreak. Conclusions. A number of simulations were made using the stochastic model with a sustainable analytical tool based on an R-free program. The need to integrate the epizootiology, epidemiology, and mathematic was demonstrated, suggesting that appropriate training should be provided by competent professionals. [ABSTRACT FROM AUTHOR]

Trucks became essential for the freight transportation systems' functioning and the enterprises considered several variables in their operations. One variable was the mileage, where fluctuations were observed with assignable causes to the enterprises in several occasions and it decreased over the time. This paper's objective was to forecast one North Benz truck's possible monthly mileage in a 33 truck fleet for the 2021 year. The truck's possible monthly mileage variation was attenuated using the moving average technique. It was obtained a mathematical model of the monthly mileage's moving average according to the truck age, the mileage's typical deviation and the mileage's relative error. The model was applied to forecast the North Benz truck fleet's performance at the enterprise. It contributed to facilitate the enterprise's decision taking on the transportation offer and incomeses. [ABSTRACT FROM AUTHOR]

In this paper, a non-linear multivariable mathematical model of a pump storage hydroelectric power plant, developed in Matlab-Simulink, is used to evaluate the performance of a Proportional Integral Derivative (pseudo derivative) controller with anti-windup, where the integral and derivative actions are of fractional order. This control is robust, maintaining its performance in the case of direct response and in the case of cross coupling response. Similarly, the advantage of using a filter to reduce the cross-coupling interaction of this system is shown. The effect of this filter, of fractional order, on the performance of the system, is shown by reducing the integral of the squared error. [ABSTRACT FROM AUTHOR]

This paper proposes the design of an IMC-PID controller with a fractional order filter (IMC-FPID) for the effective control of water distribution in a main irrigation canal pool. From real-time data and applying the system identification procedure a dynamic mathematical model of this process is obtained, which is represented by a first-order transfer function with a time delay. Based on the model obtained an IMC-PID controller with a fractional order filter was designed that behaves effectively. The simulation results compare the performance of the proposed controller with a conventional IMC-PID controller. In this comparison, the performance index of the integral of absolute error (IAE) was used. The results obtained show that the proposed controller provides lower values of this index and consequently outperforms the conventional IMCPID controller in terms of performance and accuracy. [ABSTRACT FROM AUTHOR]

This paper presents an application of the direct displacement-based design (DDBD) to a reinforced concrete frame-wall system (structures that utilize both frames and walls to resist earthquake actions in parallel). Firstly, the mathematical model is presented alongside a description of the methodology applied to determine the design displacement profile and strength proportion between walls and frames. Knowledge of the displacement profile and some recommendations for the combination of frame and wall damping components enables representation of the structure as an equivalent single-degree of freedom (SDOF) system. Secondly, the DDBD method is used to analyze and design a 12-storey building in which the displacements, storeydrifts, base shears, as well as the wall and frame strengths are determined. Then, some guidelines are presented to design the reinforced concrete structures, specifically those related to the stiffness used for the strength distribution and capacity design. Finally, a nonlinear time-history analysis is implemented in RUAUMOKO 2D, using three records from the Maule earthquake which are consistent with the displacement spectrum contained in the Chilean seismic code requirements (Supreme Decree N° 61). These analyzes demonstrate that the DDBD method provides a robust estimation of the displacement demands expected during a seismic event. [ABSTRACT FROM AUTHOR]

Introduction This paper presents a proposal to apply the meta-heuristic Optimization Based on Variable Meshes (VMO) to the discreet problem of the Traveler Seller (TSP); This model explores the search space to Objective from a population of solutions called mesh that expands and contracts in order to find good quality solutions. In this context, the expansion operator is modified in such a way that it is applicable in a discrete domain, making combinations among the solutions in order to obtain new nodes. Another element that is modified is the clearing operator, which is responsible for maintaining the diversity of the mesh in each interaction. Methodology. A study of VMO model parameters is summarized in this paper, using a set of TSP instances with different characteristics; In addition, it can be observed that the proposal of this work obtains competitive results when compared with other international reference algorithms mentioned in the state of the art. The work is structured as follows: Section 1 describes the fundamental aspects of the TSP study problem. Then, in the second, the general functioning of VMO is explained, in the third one, each of the expansion and contraction operators is defined for the study problem. Later in the fourth section a study of the parameters of the proposal and an experimental comparative analysis with the results obtained with other algorithms mentioned in the state of the art is made. Conclusions Other operators of generation of new nodes were applied in the expansion process, where a combination of solutions is made in order to comply with the restrictions imposed by the problem. [ABSTRACT FROM AUTHOR]

This paper presents, from an introductory point of view and oriented to non-experts in network theory, the fundamentals of graphs and networks that allow projecting information about cultural networks in a formal context. It also describes some of the most common measures and tools to design quantitative mechanisms for the subsequent analysis of these networks. This article does not pretend to be a complete course or tutorial on network theory, for that the reader can refer to any of the references listed at the end, but rather it is an introduction oriented to go through, in a single document, some of the details that are considered more important and that are usually leTh out of the initial explanations on the subject. [ABSTRACT FROM AUTHOR]

The effect of non-pharmacological interventions to contain the spread of SARS-CoV-2 have caused negative impacts, especially in education. Re-opening schools and universities is regarded as a high risk scenario. This paper seeks to understand, with the help of mathematical modeling, possible mechanisms through which the virus could spread in an academic environment and to quantify contagions attributable to participating in academic activities. To simulate the dynamics of contagion at the University, an agent-based mathematical model that incorporated stochastic differential equations was built using academic data for the University's 2020-2 semester. The model suggests that hybrid-attendance combined with epidemiological surveillance can produce very safe operating conditions without significantly contributing towards more COVID infections in the city of Bogotá. [ABSTRACT FROM AUTHOR]

In this paper, a multi objective optimization of asymmetric spur gear transmission is carried out using the modified Nondominated Sorting Genetic Algorithm II (NSGA II). To achieve this goal, three pairs optimization problem are formulated: minimum tooth stress and minimum transmission volume, minimum tooth stress and maximum coating factor, minimum transmission volume and maximum robustness index. Constraints considered include wheel tooth thickness, correction coefficient, and constant center distance. The optimization procedure used provides functions to find the parameters that minimize or maximize the objective functions respecting the restrictions. As results, optimal values are obtained for the robustness index and tooth stress, demonstrating the validity of the procedure used for its easy adaptation to complex mathematical models. [ABSTRACT FROM AUTHOR]

This paper proposes and solves a mathematical model to predict the behavior of precipitation in the city of Tunja. For this, pluviometric information was subjected to fitting tests to probability distribution functions, finding the Gumbel function as the optimal one. Then, by means of mathematical treatments that use this distribution and applying the multiple linear regression method, the relationship between intensity, duration and frequency of precipitation (IDF) was determined. With the established model, the IDF curves were plotted for different return periods, depending on the duration of the precipitation event. The previous procedure was applied to the data of four stations that affect the basin that crosses the city of Tunja, generating fundamental information for the decision making in the design of engineering works and in the prevention of disasters. [ABSTRACT FROM AUTHOR]

Mathematical Model of a Series-Parallel (SP) photovoltaic (PV) generator represents each module through an equivalent electrical circuit denominated single diode model, this model has associated a nonlinear equation system that describes the electrical behavior of SP generator. This paper presents a solution of this system using optimization methods widely using: Trust Region Dogleg and Particle swarm optimization (PSO) for solving the electrical model of PV generator operating under homogeneous or non-homogeneous conditions, changing the number of submodules and shading pattern. It has been made simulations about generators composed by 3 and 15 series submodules, operating under different partial shading conditions. Between the implemented methods, Trust Region Dogleg show a better performance than other methods, with 2 and 14 times less computation time than the reference method and PSO, respectively, and a RMSE equal or 50% lower than PSO. [ABSTRACT FROM AUTHOR]

This paper presents a multivariate UPD estimator, family member [A,U,T] with parameters p and s, which allows to calculate simultaneously parameters of Weibull K and C at a point Pe from the measured values of these variables in several sampling points. During the 3D estimation, the spatial relationship between the data and the associated values of elevation and roughness of the terrain is taken into account; with the estimated results, a model of wind energy resources is developed, given by a 3D mesh where to each node is associated the values of K and C. Finally, a method of combinatory optimization is described to find the values of p and s such that the mesh model is feasible and optimal for the given data. [ABSTRACT FROM AUTHOR]

This paper presents the procedure of tuning and simulation of an adaptive predictive control strategy to control the longitudinal and latero-directional movements of a unmanned aerial vehicle (UAV), using the Matlab ® - Simulink® platform. Uses the mathematical model of a UAV which are initially performed simulations of the system in open loop, identification is carried on online, and predictive control and PID controllers algorithms are implemented with the parameters obtained, to control the angle of pitch, roll and yaw. Control strategies used presented a good performance and manage to stabilize the aircraft properly. Finally, they are presented and analyzed the results of the performance of the system with predictive control and PID control using metrics of the integral of the error and of the work of the manipulated variable. [ABSTRACT FROM AUTHOR]

Software Development Life Cycle (SDLC) models guide trough the development or maintenance of software products. Currently we can find several SDLC models applied in different contexts. A well-known SDLC is the waterfall model, which its stages are performed in a sequential order. With the aim of gaining more knowledge about a waterfall-like SDLC model, in this paper we report the findings of a controlled experiment that studies the quality and efficiency of a waterfall-like SDLC model applied by solo and pair programmers. The studied SDLC model is contrasted with an iterative-like SDLC model defined as 'ad-hoc' that is used as a control group. Concerning the quality, our results suggest that any of these two SDLC models yield similar defect detection rates. Regarding the efficiency, results suggest that a waterfall-like SDLC model significantly requires less number of builds to complete the programming assignments. We did not observe significant differences between pair and solos programmers. Even though the criticism arose around the waterfall SDLC model, our results suggest that under certain contexts a waterfall-like SDLC model can yield beneficial effects, as the one observed concerning efficiency. [ABSTRACT FROM AUTHOR]

Optimizing biomass drying to improve combustion processes is one of the main tools available to small and medium agroindustrial producers in rural areas of Colombia to be competitive. For this reason, the development of experimental studies becomes a priority to improve the competitiveness of the rural sector in Colombia. In this way this paper shows the development of the experimental study of drying kinetic of panelera's sugar cane bagasse, as well as its contrast with mathematical models used for the prediction of the drying kinetics. The results obtained can be useful as a reference for the effective design of sugarcane bagasse drying systems. [ABSTRACT FROM AUTHOR]

The present paper presents a study of the rheological parameters influence of lateritic hydromixtures with the energetic parameters of the pumping systems, which guarantee productivity when obtaining nickel sulphide. Experimental studies such as X-ray diffraction techniques, X-ray fluorescence and particle size analysis were carried out to model apparent viscosity, initial shear stress, mass consistency index and flow index. The above, based on the following factors: temperature, solids content, chemical and granulometric composition. The results showed that the lateritic suspensions behaved as non-Newtonian fluids with plasticity, due to their character of polydispersed materials, with a predominance of fine granulometry (particles less than 0.045 mm), which explains their rheological behavior, adjustable to the Bulkley - Herschel model at temperature values of 28 to 90 °C and solids concentration of 37 to 48 % (w/w). It is concluded that the use of a mathematical model that relates the rheological parameters of the lateritic pulp and the energy parameters of the pumping system contributes to energyefficiency of the pulp feeding in the acid leaching process. [ABSTRACT FROM AUTHOR]

Dengue is a viral infection transmitted by the female Aedes aegypti mosquito that lives in all tropical and subtropical regions of the planet. In Cali, Colombia, despite the controls that health officials say they are doing, this year, there have been more than 9,000 cases of dengue, of which some have been serious and others have become lethal. For the case of dengue virus transmission, mathematical models to simulate the dynamics of the infected population, either human or mosquito or both, allow a good understanding of the dynamics of the virus, so they are a good tool for monitoring and controlling the disease. However, for this tool to be really useful in a specific case, the models must be tailored to the particular characteristics of the region where you want to use them. In this paper, we present the fitting of two mathematical models to the urban area of Cali, Colombia. Initially, based on the natural behavior of the Aedes aegypti mosquito in a region as the area of interest, we estimate some of the parameters of the models, taking into account the existing literature on this topic. Subsequently, we estimate the others parameters as the (non-linear) least squares solution that best fits the output of the models to the data of reported cases of dengue, according to the Municipal Secretary of Cali, in 2010. [ABSTRACT FROM AUTHOR]

This paper presents a methodology for the determination of the coefficients of the mathematical expression of each of the characteristic curves resulting from the placement of rotodynamic pumps in series, starting from knowing the curves of one of them. The proposed methodology is based on the direct relationship that exists between the areas under the curves (polynomials) of a pump and the one corresponding to the case in question (n pumps in series). For this reason, the procedure has been called the Area Method. The aim of this procedure is to determine the coefficients of the characteristic curves resulting from the combination of rotodynamic pumps in series, as well as to provide a tool for knowing the method of obtaining of such characteristic coefficients. [ABSTRACT FROM AUTHOR]

Crushing mathematical modeling using particles population balance method is a fundamental tool for process analysis, optimization and design. This paper deals with the evaluation of the fracture events and process in cone and rolls crushers. For that proposes, is taken as reference Whiten (1972) structural model modifying fragmentation distribution function. This function was replaced by Austin and Luckie (1972) expression. For model development, was created an algorithm using Matlab 13a like determining resource of fractures parameters. Model estimated error for evaluated crushers established the viability of its use for modelling and simulation, particularly for rolls crushers that even before were simulated by simple fragmentation models. Classification and fragmentation distribution functions obtained, describe the events and process fracture essentials that take place in both crushers. [ABSTRACT FROM AUTHOR]

Actually, customer satisfaction is considereda critical success factor for organizations. Determine the level of service and meeting the expectations of customers has been studied for many researchers and entrepreneurs. To this end they have created and used various tools, some more accurate than others, but there are still shortcomings, none takes into account all available information and knowledge. This paper proposes a new procedure that will allow to measure with the employment of compensatory fuzzy logic the level of customer service through the modeling of predicates of the variables behavior (tangible or subjective) involved in the client-provider relation. In addition, shows the results obtained from the application of the procedure in the case study, reaching to determine how true is that the level of service of the company meets customer expectations. [ABSTRACT FROM AUTHOR]

Tourists plan trips based on their personal preferences and the point of interest information at destination. This paper propose the formulation of optimization problem for their multi-day planning sightseeing where the preferences of the tourists on the points of interest and travel time constraints are fuzzy. The soft computing methodology proposed to solve the problem integrates fuzzy optimization methods with a constructive metaheuristic. Computational results on instances from the team orienteering problem benchmarks are analyzed. [ABSTRACT FROM AUTHOR]

This paper presents the results obtained using a mathematical model, to simulate different situations plugging on issuers irrigation systems micoirrigación in the cultivation of guava in two subunits irrigation the UBPC the Tezón in Ciego de Avila province. The model is that the uniformity of the emitter flow is affected by the hydraulic factor, manufacturing and plugging. For the preparation of the experimental data obtained with the implementation of these procedures has been developed a computational tool using an Excel 2007 worksheet that allows quickly and with a wide margin of safety obtain fundamental results of these calculations. The aim of this work is to simulate seals issuers using mathematical modeling in micro irrigation systems. [ABSTRACT FROM AUTHOR]

Blocking Contours are a graphical method. By means of this technique, the gear designer obtains the values of the correction coefficients, which meets the undercutting geometric constraints, contact ratio, interference and teeth pointing. This paper presents a mathematical model that allows non-interactive construction of blocking contour in the field of cylindrical external gears with asymmetric teeth. For this purpose, the equations defining the mentioned restrictions are modified and it is set the sequence in which they should be calculated. This makes possible the analytical use of the limits of blocking contour for establishing the dependence between the geometric parameters of these transmissions, thereby facilitating synthesis work. [ABSTRACT FROM AUTHOR]

The warmth is a subjective phenomenon, fundamental in human relationships. The warmth is contagious, so may be a factor favoring care, but there is no consensus on its definition and domains. Since warmth is a predictor of user satisfaction, it is relevant to use an appropriate way to measure it; however, there have not been found ways to measure it, which motivated this revision. The three-stage procedure of Luiz Pasquali was used to do that, which considers Theoretical, Empirical and Analytical phases. This paper presents the results of the first theoretical phase: behaviors associated with warmth previously identified in the literature. Objectives: To identify behaviors that represent the warmth of the Nurse by reviewing specialized literature, and to operationalize the construct warmth and related variables. Method: Integrative literature review that included the exploration and analysis of the evidence on warmth, which corresponds to the first stage of the research project entitled: Construction and validation of a scale for measuring this warmth in Nursing, which aims to build and validate a scale to measure this phenomenon. This work corresponds to the Theoretical Phase of Pascuali's model. Definition of warmth was revised by using dictionaries and technical articles from various repositories. The descriptors used were "warmth" and "warmth and nursing" in Spanish and English. To define the construct and its variables, the Ethel Bauzer's procedures and Floyd Fowler's method were also considered to supplement the Pascuali's model. Results: Formulation of the construct Warmth in Nursing which includes, 2 domains, 28 verbal variables, 9 nonverbal variables and 93 behaviors. Conclusions: The results of the theoretical phase of the applied model, allowed to formulate the construct domains and variables of Warmth in Nursing. These contributions are of interest for the management of nursing care and teaching, as are directly related to user satisfaction. [ABSTRACT FROM AUTHOR]

This paper presents results of the optimization project to the control loops of the distillation tower No. 2 of the Amtex Company due to the low performance that presents the tower. Toolbox of Matlab® can be obtained the mathematical model that describes the dynamic of plants of temperature and feed flow from the tower and from these models, it comes to tune three control strategies for each loop: PI controllers, PPI controllers with Smith predictor and PI controller with gain scheduling they are tuned using the method of Ziegler-Nicholls. The controllers are implemented in the Control Builder M, programming software of AC800M controller. Finally, it compares the performance of these controllers already applied in the control loops of the real system. [ABSTRACT FROM AUTHOR]

This paper present the wind speed measurements analysis for a weather station located in Barranquilla city, northern in Colombia, by the Institute of Hydrology, Meteorology and Environmental Studies of Colombia (IDEAM), for the years 2012 and 2013, using measures of central tendency,relative and absolute frequency histograms, that allow estimate the most frequently velocity in this zone. From probability density function (pdf) of Weibull calculated from the histograms for the years 2012 and 2013, it was possible to predict the behavior of the wind speed by 2014, incurring small statistical errors in the prediction, which allowed a successful wind resource characterization of the place, enabling the development of models to convert the wind power to electrical energy. [ABSTRACT FROM AUTHOR]

Although Sociology was born with scientific vocation, its current status as a scientific discipline seems not to enjoy good health. Departing from this idea, the purpose of the paper is threefold: first, several arguments for explanations of social phenomena through mechanisms will be reviewed. Such explanations can offer a suitable way to Sociology to be able to develop as an authentic science. Second, the idea that such explanations can be computational programmes created by agent-based modelling will be justified. Finally, it will build new arguments about how such explanations can avoid the ambiguity and the obscurity conceptual that a part of sociology suffers; reduce its theoretical fragmentation and strengthen the multidisciplinary dialogue with the purpose of researching in depth social reality as well as being able to design effective policies against several social problems. [ABSTRACT FROM AUTHOR]

In this paper, the mathematical modeling and simulation of the automatic control of the quintuple effect of evaporation of a sugar mill "El Palmar" in Venezuela is made. The multiple effect consist of 5 evaporators Robert type, with equal characteristics, connected in series. Starting from the desired operating conditions and control requirements: level in each evaporator vessel, cane syrup concentration and pressure in the fifth evaporator vessel using mass balances, balance on solids for each evaporator and energy to the barometric condenser is present at the output of the fifth vessel, the nonlinear model of the process is obtained, resulting in a system of multiple inputs and multiple outputs, with strong interactions between variables. In the design of the system of the automatic process control, we are interested in maintaining the variables that characterize the performance of it and they are regulated in an operating point; we proceed to linearize the model around an equilibrium point, resulting in a new model in terms of the variables variations around an environment from that point. Then, it is processed the model obtained in terms of input and output relations, based on the characterization of it in terms of variables and transfer relationships in the complex frequency domain. Finally, the evaporation process is simulated, establishing the adequacy of the model to the real process. [ABSTRACT FROM AUTHOR]

In this paper, the modeling and analysis of one tower Workover Rig belonging to a maintenance facility for oil and gas wells is presented. When performing the maintenance of this tower, it is detected that one of the elements of the structure has some deformation. It was decided not to put it into operation and submit it to research. The modeling of invariants as well as ways of modeling soil structure interaction is discussed. It was necessary to determine the material properties with the performing of test of some samples taken on two components of the tower. The structural behavior of the tower to operating loads are then studied, proving that the effect of the deformed element in the structure is not significant for the stresses to which are subject. [ABSTRACT FROM AUTHOR]

This paper propose an additional plan of production in a Company, including employees in a handicap condition, which will count with different times to execute the different tasks and sometimes incompatible in specific activities. The Model of mixed integer linear programming seeks to maximize production as well as the respective cash flow. The tributary benefits of the Colombian government associated to the inclusion of handicap condition personnel, are considered for the model. The Model is validated with a case study. [ABSTRACT FROM AUTHOR]

Social trust and political trust are, amongst others, key social capital factors. This paper examines the accuracy of their measurement and comparability across different time periods. Multiple-group confirmatory factor analysis (MGCFA) is performed and different levels of measurement invariance (configural, metric and scalar) are tested. Data used are from European Social Survey for the years 2002, 2004, 2006 and 2008, in relation to Spanish citizens. Factor means for social and political trust are compared across time in Spain. Political and social trust show stability across time, except in 2004 with a higher level of political trust and 2006 with a higher level of social trust in Spain. Comparison with traditional composite scores shows the inaccuracy of such measurement for data comparison across time. Finally, consequences of using inaccurate measurements, and methodological recommendations concerning model fit structural equation models are delineated. [ABSTRACT FROM AUTHOR]

In this paper three new algorithms for the random generation of permutations of degree n are shown, two of them for the Symmetric group Sn and one for the Alternating group An, in such a way, that they are mainly carried out by means of the operation of additions mod no mod i, i = n.2. [ABSTRACT FROM AUTHOR]

This paper describes a hypothetical simulation model developed in ProModel ® for a call center inbound calls type. Which includes the choice by users of the service type required as television, phone or internet, or if the service is a home or business level, and the possibility to select from options to request information of the services offered by the company, making a complaint or report of a technical failure in the contracted service. Based on secondary information collected, input distributions are specified for the simulation of the random behavior of the phenomenon and conducting experimental runs under a 2k design. The proposed design allows evaluating different scenarios that include factors associated with the ability of operators such as work experience, education and the type of training, and technical factors such as the number of phone assistance lines. Next, the effects of the studied factors on service rates and abandonment rates and on the average time spent in the system are evaluated, leading to identify system configurations that have higher performance. [ABSTRACT FROM AUTHOR]

This paper addresses an architecture for the conceptual design of remotely operated vehicles (ROV). The proposed architecture is based in an extensive literature review and the experience acquired during 20 years with the development of three ROV systems that where designed for underwater inspection. The ROV is divided into five subsystems: vehicle, surface station, surface/vehicle interface, control system, and software. For each subsystem, functions and tasks are defined, components are listed, interrelations with other subsystems are established, and commonly used alternatives are proposed. The subsystem's division used for the conceptual design process allows one to avoid problems in the advanced stages of the robotic exploration system development. [ABSTRACT FROM AUTHOR]

This paper presents a new multiobjetive mathematical model for optimization of facility layout problem with unequal areas called UA-FLP with fixed dimensions. One of the objectives is the minimization of the material handling cost and the other one is the minimization of the closeness relationships according to factors that are independents of the flows and costs. The validation of the mathematical model was made with problems found in the literature. The result was that the proposed model represents the unequal area facility layout problem with fixed dimensions optimizing the material handling cost and the closeness relationships for small problems and finding good solutions for bigger problems in 10,000 seconds of computer time. [ABSTRACT FROM AUTHOR]

This paper presents the model of a virtual drive system of an underwater mobile platform inspired by biomimicry, selecting the subcarangiform mode of fishes as locomotion system which is based on body and caudal fins (BCF). This model uses two-thirds of the body for thrust and one of the most important features is the high maneuverability. The development of the model is based on simulation by designing the 3D model of the prototype using a computer aided design software (CAD), an analysis by considering the direct and inverse kinematics and a navigation control system by implementing the fuzzy logic. The algorithm implemented to solve the inverse kinematics is based on geometric methods considering the workspace and dividing it into subareas in order to analyze position, velocity, acceleration and torque for every joint of the robot fish. Also, a navigation control algorithm was developed using the fuzzy logic as non-linear control method. The results represent an approximation of subacarangiform mode offish behaviours for future physical implementation of an underwater platform inspired by biomimicry. [ABSTRACT FROM AUTHOR]

In the decision making process of the enterprise field, and with the purpose of finding the best solution within a set of possible alternatives under the common problematic of resources shortage, the Methods and Quantitative Techniques have become a major tool. Therefore, the methods and quantitative techniques have become an important tool. Specifically, Linear Programming and in Integers is one of the most widely used mathematic programming technique. The present paper delimits the three-months production optimal plan which increases profit in the manufacturing of supplies in UEB 102, Talabartería THABA Company. Linear Programming and in Integers models are developed, and an analysis of outcomes resulting from the usage of WinQSB is carried out. [ABSTRACT FROM AUTHOR]

This paper presents the mathematical design of a small part of a reference epistemological model which, once concluded, should support the educational organization of a study process comprising: the development of the functional modelling with parameters, elementary differential calculus raison d'être in high school, and the first developments of calculus in several variables at university. Hereto we focus in the moment in which we already hold the derivative as a work tool to show the progressive development, and the relative completion of mathematical praxeologies that are built as progress gains ground in the different levels of functional modelling. This proposal is submitted from an Anthropological Theory of the Didactic scope and represents a small contribution to the didactic purpose of placing the mathematical modelling as an instrument that allows to articulate and give meaning to school mathematics. [ABSTRACT FROM AUTHOR]

Electric arc furnace provides a relatively simple way for melting metals. They are used in the production of highly purified steel, aluminium, copper and other metals. However, they are considered the more damaging load for the power system. It is very important, therefore, to count on arc furnace models for determining with high degree of accuracy the performance of this type of load. In this way, it would be possible to assess the impact in terms of power quality indices for the power system to which they might be connected. When using electric arc furnace models in practice, a key issue is the calibration of the parameters of the model. In this paper, we show a procedure for calibrating all the parameters of an AC electric arc furnace model using real measurements of voltages and currents. It uses a multilayer neural network as an emulator of the electric arc furnace model. The neural network is trained using data obtained from the simulation of the electric arc furnace model implemented in Matlab®-Simulink®. Once the network is trained, the parameters of interest are obtained by solving an inverse problem. Results obtained show a maximum percentage error of 4.1 % for the rms value of the current involved in the electrical arc. [ABSTRACT FROM AUTHOR]

This paper proposes a decision strategy related to the use of SCOR (Supply Chain Operations Reference Model) metrics in an organization that is a very common tool to conduct exogenous benchmarking by comparing SCOR values of the company with respect to those of the leaders of industry. We propose instead an endogenous or internal benchmarking comparing those SCOR values with optimal ones from the same company associated with a mathematical optimization process of the firm. Starting with the case of indicators associated with suppliers operations, we highlight the usefulness of the endogenous comparison where differences between the optimal and actual SCOR values leads to some gaps which effectively guide some improvement paths. These paths may include the need to review SCOR lower level metrics based on the analysis of the upper SCOR level. Given the focus on optimization, these improvement proposals consider the best use of available resources in the company without additional investment. [ABSTRACT FROM AUTHOR]

In this paper we development a hybrid algorithm of machine learning for the automatic locking of web pages that incite to violence through content snuff. We describe of the current situation of the problem to be solved, and we give to know the selection process of the techniques for the development of the hybrid algorithm. Also, we show the mathematical model and results analysis. [ABSTRACT FROM AUTHOR]

The last stage of classical transport modelling, known as the sequential model of the four steps, estimates the flow pattern of the system. Then, in a post-processing phase all measures of system performance such as the level of service and externalities are estimated. This paper compares the estimated BPR and conical volume-delay with data taken in six multilane roads in Bogota, finding ranges of recommended function parameters values. We concluded that the values traditionally used for these functions are not the best for explaining the congestion that occurs in the environment studied. [ABSTRACT FROM AUTHOR]