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This paper proposes the geometry-based polylinal routing method as a solution for motion planning in object sorting exercises in manufacturing processes. This algorithm is based on geometric properties that arise from the interaction among objects within the configuration space. The method proposed in this paper, during its experimental phase, successfully generated smooth routes with a processing time ranging from 62.5-125 ms on a computer equipped with an AMD Ryzen 7 2700X Eight-Core 3.70 GHz processor and 16 GB of RAM. When compared to the RRT algorithm, it exhibits a higher efficiency of 38% to 48%, resulting in a reduction in iterative processes and a shorter response time. Therefore, the proposed method presents a viable solution for addressing motion planning scenarios in object sorting exercises. [ABSTRACT FROM AUTHOR]

A suitable design of manufacturing facilities can increase the efficiency of a company's internal operations by optimizing material handling and flow costs. This paper addresses the facility layout planning problem (FLP), modeled as a quadratic allocation problem (QAP), applied to a company dedicated to the production of liquors. The problem was solved using the Computerized Relative Allocation of Facilities Technique that belongs to the heuristic algorithms, which allowed us to determine the best allocation of the departments, considering the distances traveled and the material flow costs. Subsequently, a simulation was carried out to evaluate the new distribution given the company's daily activities, considering the variability of loading and unloading times. The simulation results suggest that, if the new layout is implemented, material flow costs and times would be reduced by 13.22 % and 4.28 %, respectively. [ABSTRACT FROM AUTHOR]

This paper presents the modelling and simulation of a complex system applying the hierarchical coloured Petri nets method to represent the failure and repair processes, as well as obtaining statistical data indicating its performance. The simulation was performed on the model of a mechanical system characterized by the FAMAE SG 542-1 war rifle, commonly used in the Chilean Army, through the CPN Tools and Python software representing how components perform of operation of this weapon. This behaviour is recorded through both software, obtaining the simulation data so that it will be possible to predict the condition of a component and the system in the future to generate corresponding action plans. [ABSTRACT FROM AUTHOR]

This paper presents a comparison of some simulation tools for photovoltaic systems. The analysis was made considering four criteria: historical citations, accessibility, user friendliness and simulation. Each criterion includes aspects which have a score assignation. Finally, a weighing was made to define the computational tool with more advantages. The simulation software with more advantages for photovoltaic system simulation are PVSyst and PV*SOL. Both its interface and the information given in the simulation, made them very complete tools for the analysis of the energy production in this kind of systems. Simulation software are needed for the analysis of the operation of photovoltaic systems. Among the most used are: PVSyst, PV*SOL, SAM and RETScreen. The evaluation of these tools allowed to identify that PV*SOL is the software with more advantages and strengths. [ABSTRACT FROM AUTHOR]

This paper will analyze the concepts that result from the combination of interactive narrative and graphic realism in video games. Their review is important due to the presence of software such as video game engines, that have been available to developers and enthusiasts since 1998. Many are free, simple to use and with resources for learning as video tutorials. However, it was found that studies about the graphic and narrative balance in video games are scarce. This paper reviews theoretical documentation, statements of professionals linked to the industry, and examples of interactive narrative aimed at entertainment in fiction genres and from real events. As a conclusion, only the narrative or only realism does not activate a better global experience in video games adding visual and interaction factors to that balance, each with a different factors. Each with a different weight but necessary according to the theme and objectives of its creators. [ABSTRACT FROM AUTHOR]

This paper presents a teaching system for Higher Education Institutions in careers such as logistics, supply chain, internal logistics and related fields, through the understanding of mathematical procedures oriented to simulation. Presenting a case study of material requirements planning (MRP) that provides a production and supply schedule, according to the sales forecasts of a Distribution Centre (CEDIS): The production standards and delivery times of the suppliers, which respond to the What, how much and When to supply. (Velasco Flores, 2017): MRP is a set of techniques that uses bill of materials data, inventory data and the master production plan to calculate material requirements. It suggests releasing material replenishment orders and rescheduling open orders, based on the time lag. (APICS, 2019): The MRP I mathematical procedure presented in this research is based on two fundamental aspects: 1. It refers to finished products. 2. This system is carried out according to the needs of each item (independent demands and product structure): MRP I is based on the calculation of the net needs of the articles and components, introducing a factor not considered in the traditional methods of stock management, which ultimately leads to modulate the time, with due planning with respect to its use, to subsequently simulate it in a software. [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]

Introduction- This paper presents the results of a research project. The objective was the creation of a model and simulation of the cocoa production chain in Colombia. It was funded by the Universidad Nacional Abierta y a Distancia. Objective- The purpose of this paper is to present a simulation model of the cocoa production chain in Colombia. Methodology- For the approach to this research, authors such as Absalón Machado --who offers a theoretical framework to present the understanding of agri-food systems--, were taken into account. A systemic perspective was also implemented for the research. In fact, it was modelled using system dynamics, which is based on the notion of feedback, delays in time, the idea of accumulation and reason for change, typical of differential and integral calculation. In this way, field work was carried out in terms of direct observation of international cocoa crops and processing plants. Results- A mathematical model that recreates the behavior of the cocoa production chain was obtained and was adjusted to the behavior of the chain for the time horizon studied. The model can be used to understand the dynamics of the chain as a whole based on the flows of information and material in the system. Conclusions- It is concluded that the use of system dynamic models, which represent a productive chain, can be used to promote decision-making processes based on simulated experimentation. This allows us to gain an understanding of the dynamics of the productive chain. Furthermore, it is evident that in situ perception of the phenomena to be modelled promotes a better representation of them. [ABSTRACT FROM AUTHOR]

This paper reflects on the importance that the dialectic of hypothesis - conjectures can have, not only for the development of demonstrative thinking in students, but also for the development of stochastic thinking. It argues for curricular reasons, for an approach to teaching based on problem solving, for a way of solving problems that considers simulation as a method of resolution with heuristic content and, finally, for new proposals on mathematics that the citizen of the XXI century will require and that includes the analysis of data in contexts of uncertainty. Consequently, a proposal is presented for the training of pre-service teachers to enable them to deal with such challenges. [ABSTRACT FROM AUTHOR]

Stream processing platforms allow processing and analyzing realtime data. A recognized system for this purpose is the so-called Storm platform, an open-source system for distributed computing, which is a scalable, fast and, fault-tolerant. The Storm platform may be deployed on a large number of processors. However, determining the proper number of processors that are suitable to execute a given Storm based software application is a challenging task, especially if the application is intended to serve a very large user community. One way of solving this is by employing a simulation model that allows the evaluation of its performance under different workload scenarios. In this paper, a simulation model of a Storm application using the DEVS formalism is presented, then, an equivalent model is described using Timed Automata (TA). Throughout a procedure called "Bisimulation", it is checked that both models are effectively equivalent. Finally, the model defined using TA is formally verified evaluating its properties, proving that the simulation model has the same behavior as the real applications. [ABSTRACT FROM AUTHOR]

This paper presents the results of a research project for developing Rusty Roads, a videogame that simulates line follower robots in tridimensional, competitive environments. During the software development process, it was necessary to define the key physical factors that could affect the performance of the robot. A real robot was considered to define real parameters for the simulation, and to define discrete equations for simulating the robot in the Unity framework, comparing their accuracy with that of continuous, exact equations specifically developed for this study. This paper presents the process for obtaining and testing those equations, which were the foundations for the successful development of the simulation layer of the videogame and allowed the subsequent creation of its 3D visualization component. [ABSTRACT FROM AUTHOR]

Given the importance of knowing the mechanical response of the soil as one of the variables to be taken into account in the design of implements and machines capable of preserving the physical qualities of the soil, several constitutive models have been developed that represent the soil as a non-linear material elastic or elastoplastic. The objective of this paper was to analyze the current state of the constitutive models used in the modeling of agricultural soils in order to define which of them is the most adequate to simulate the mechanical response of agricultural soils with clay texture (Oxisol, Inceptisol and Vertisol). Constitutive models that are used in the simulation of the mechanical response of agricultural soils by means of the finite element method are analyzed critically, taking into account the properties and parameters of input, determination of these and their implementation in the softwares for simulation using the finite element method. Finally, it is concluded that the Drucker Prager Extended model as the most adequate to simulate the mechanical response of an Oxisol, prioritizing in this decision its simplicity, convenience when determining its parameters, accuracy in estimating the stress-strain relationship of the soil, and inclusion in most commercial software. [ABSTRACT FROM AUTHOR]

This paper shows a model of a feedback system of a connector assembly line. The feedback is established as a control system, where the result of certain variables such as pending orders to be delivered, are introduced again to the model in order to improve its performance. The dynamic model was developed in the simulation platform of the VensimPle software, student version, with the system dynamics methodology. The main results are that the feedback loops established in the model allow the productive system, inventory levels and production flows of the stations to remain stable; this considering two scenarios: production capacity greater and less than demand. It was demonstrated, when the client's requirement exceeds the productive capacity, pending orders are generated, but the levels of inventories and productive flows remain stable. [ABSTRACT FROM AUTHOR]

A concept that has gained attention in the last years is the existance of cognitive biases and their influence in decision making and behaviour of human beings. Teams in the operating room are formed by different medical specialities with varied levels of experience, everyone has a role and every one can make decisions that have an impact in the patient. This decision making process might be based in previous experience, clinical reasoning, and context; the need to make a rapid diagnosis and treatment in some situations makes the anesthesiologist especially vulnerable to cognitive bias. We present different types of cognitive bias that might be present in the operating room for example the attention bias in which a relevant stimulus like the airway management could make the hemodynamic aspect go unnoticed. The goal of this paper is to aware anesthesiologists in particular about this cognitive biases, their presence in the decision making process in the operating room and to share a couple of ways to prevent them. [ABSTRACT FROM AUTHOR]

The Job Shop scheduling problem has been extensively studied in the last decades due to its importance and computational complexity. However, a large part of the papers address the static and deterministic version of the problem. This work presents an integration of a simulation model with an optimization method in order to solve the dynamic job shop scheduling problem. The proposed model integration is accomplished using out-of-process components, through the ActiveX Automation technology and the Visual Basic for Application, in which a simple Genetic Algorithm runs as a free-standing application. Results of the proposed method were compared with some common dispatching rules and showed that the proposed approach the scheduling problem efficiently. Moreover, the solutions generated by GA are less sensitive to variations in demand, which is quite significant in such environments. [ABSTRACT FROM AUTHOR]

Although cases of Christian stigmatization have become rare, general interest in this unusual physical phenomenon endures. Yet, a study of the cases of Madeleine Lebouc and Yvonne-Aimée de Jésus has revealed that their stigmata proceed either from self-mutilation or fraud. However, that's not the main point. Research into this peculiar form of relationship between a subject and his body proves to be quite rewarding, mainly because the phenomenon is sustained by a mystic relation to Jesus. Based on Freud's and Lacan's theories and on clinical elements, the present paper describes the two main functions of stigmata for these subjects, i.e. the processing of uncontrollable jouissance assigned to the body itself and the development of a process of representation that enables the subject to accept it and to deal with it. [ABSTRACT FROM AUTHOR]

This paper analyzes the vehicular mobility in 3 specific points of the municipalities of Riohacha and Maicao, La Guajira Colombia. Variables of vehicular flow such as queue arrival times, density, permanence, infractions and other implicit ones were used. Observation and description processes are carried out over four continuous months in critical hours; the flow variables that affected the selected points, causes and effects were identified and described, which are represented using influence diagrams. The whole process was simulated, using high performance software such as PTV Vissim 8 and Vensim PLE. It is recognized that the vehicular mobility in the studied points, the congested genres due to the high frequency of vehicles that transit and that the current traffic regulations are something that don't help enough to improve the flow. In addition to infractions, accidents and situations of intolerance, toxicity is generated in the environment by the emission of CO2 by vehicles waiting at each critical point, matters to which authorities still do not pay attention. [ABSTRACT FROM AUTHOR]

This research paper presents a proposal for the implementation of experimental and simulation activities, based on the principles of active learning methodology, for teaching and learning the factors that modify the rate of reaction. This strategy was applied to tenth graders from San Lorenzo Secondary School, located in the town of Suaza, in Huila department (Colombia). For this purpose, two groups are taken, one of which integrates the development of the activities through the practical work and another one, which does so using the "Virtual LabCin" chemical kinetic experiments simulator. The proposal integrates the application of a previous ideas test, the development of interaction-demonstration workshops, and the implementation of the final test. According to the results, a temporal confrontation analysis (before, during and after) is run. This analysis determines that the didactic proposed not only allows establishing a positive and favorable impact on the performance and acquisition of knowledge of the concepts addressed, but also provides the development of intellectual and procedural capacities, which stimulate proposition, confrontation, communication and the development of ideas. [ABSTRACT FROM AUTHOR]

This paper presents and analyzes a flipped classroom proposal for teaching production programming technics, with the aim of increasing the interest, collaboration and satisfaction of the students in comparison with traditional teaching. A real size production plant problem is presented to the students in order to make decisions on tactical level and operative level. To make the decisions, the concepts linked to the different tools are supplied to the students, with the support of software applications. These incorporate smart technics applied to each step of the planning process. The effectiveness of the tools in the key indicators of production area are validated calculating indicator values that could be used as student grades criteria. The qualitative evaluation of preliminary tests shows that the use of this kind of educational model improves motivation, professor-student interaction and academic performance. [ABSTRACT FROM AUTHOR]

This paper studies the adoption of simple rules of thumb for scheduling surgeries in a health care institution with limited availability of specialized personnel. Discrete events systems simulation is used with the goal of identify the one that is the most appropriate to be used to improve opportunity and operating room theatres utilization. It is also studied the use of dedicated operating blocks, that are used only to allocate most demanded surgeries, and it is demonstrated that this strategy might be able to improve systems performance when combined with an appropriate dispatching rule. Results suggest that this is because, compared to the current situation, the effect of pressures on the negotiation with the outsourced personnel is reduced. [ABSTRACT FROM AUTHOR]

With the simulation and optimization of a manufacturing system, the input parameters are sought to obtain the best performance of the system, considering in many cases a single objective or measure of performance. However, many decisions involve multiple criteria, usually in conflict. Currently, companies are required to improve their profitability as well as to reduce their impact on the environment and use energy rationally. In this paper, the wood products manufacturing process of a small company was studied to determine redesign alternatives, with simultaneous economic and environmental criteria. A simulation model of the system was built, which was validated and verified, and an optimization model for it in which two objectives were combined in a single function, incorporating in it the preferences of the decision makers with respect to each criterion. Results expose that combining both criteria it is possible to achieve substantial improvements in the benefit, at the same time that generating less emissions than if only the economic objective were pursued. It is concluded that simulation and optimization combining both criteria can improve economic-environmental performance in wood manufacturing systems, even in small companies. [ABSTRACT FROM AUTHOR]

There are many tools to model the business processes of a supply chain (SC). However, they have a high degree of complexity that makes difficult the concatenation between conceptualization, structuring, and design. Colored Petri-Nets (CPN) is a powerful tool for modeling and specification of complex systems; however, these are still in a stage of development. This paper presents a methodology that integrates the capabilities of modeling, simulation, and analysis of the business processes of a SC with the purpose of reducing the complexity of modeling and analyzing results. The results obtained explain the levels of utilization of the resources; likewise, through the properties of the CPN, the behavior of the textile SC as a whole could be known. [ABSTRACT FROM AUTHOR]

This paper proposes a methodology for the analysis of power quality in industrial electrical installations. Initially, a multipoint measurement is performed, then the phenomena that most affect the industry are identified and analyzed, then the system is modelled and adjusted to the real behavior, and some solutions are proposed and simulated. Subsequently, a case study is selected and the power quality study is carried out on the basis of the proposed methodology and according to the parameters of the NTC 5001 standard. Finally, the advantages of using multipoint measurement and modeling in power quality studies are established. [ABSTRACT FROM AUTHOR]

The cell and photovoltaic module is typically represented by an equivalent circuit. The correct equivalent circuit modeling is nowadays an essential tool for designers and planners, for studies and optimizes energy in photovoltaic systems. However, the extraction of the equivalent circuit parameters is still a difficult task and typically requires experimental data and calculation procedures, generally not available for the user. This paper presents a new methodology, which enables the exact calculation of the parameters and electrical quantities, simple diode model with five parameters, obtained from the data provided by manufacturers in the data sheets of photovoltaic modules. Finally is showed the validity and accuracy of the proposed methodology, comparing experimental data and curves obtained by the manufacturer of a commercial module, with those obtained by the proposed mathematical model is checked. [ABSTRACT FROM AUTHOR]

Chronic pain is considered one that persists for more than three months. The treatment of pain is complicated even more when the health professional has a second thought about a possible malingering. This is a deliberate attempt to simulate a disease or disability, exaggerating the symptomatology, with the aim of obtaining a benefit, which is usually of an economic type. This paper depicts the case of a patient treated for chronic pain in a pain unit, which is suspected of obtaining an economic benefit due to permanent disability. After the evaluation, a malingering process is ruled out and a cognitive-behavioral treatment is started. We describe the evaluation that allows to rule out the suspicion of malingering, the cognitive-behavioral treatment with the choice of scientifically endorsed techniques for the treatment of chronic pain and the results obtained. [ABSTRACT FROM AUTHOR]

This paper evaluate the Mexican pension model supported by the law of the Mexican Social Security Institute (IMSS) of 1997, the study review the theoretical aspects of the pension model. The principal aspects of the retirement condition are analysis by a set of scenarios with a deterministic and stochastic approach, the variables uncertainty are modelated with a stochastic process, the analysis use the Monte Carlo simulation with the projection of thirty years. The evaluation shows the Mexican pension model satisfies the ideas of Modigliani in the life cycle theory and the precepts of the Overlapping Generations Model. One of the relevant result is that the pension model partially are self-sufficiency by the population, since an important part of the workers cannot save enough incomes to support their minimum pension and hold the liability to the State. Workers with a higher income who achieve savings that can guarantee a pension higher than a minimum wage should reduce the standard of living to adapt it to the level of income in the retirement phase that corresponds to approximately a fifth of the income that was had at the retirement time. [ABSTRACT FROM AUTHOR]

The primary objective of this paper is to show the methodology assessment to construct artificial stock markets, determining: first, a Colombian price generator model; second, modifying the cellular automaton model developed by Fan in 2009; third, building a rational automaton model, adapting the Alexander Filters methodology. The models are compared using their consensus (volume of Buyers, Holders, and Sellers). This research determines that rational agent-based modeling allows a less predictive behavior and a greater impact on the information use, similar to the Efficient Market Hypothesis; moreover, there is no convergence between rational and behavioral artificial stock markets. Therefore, we propose a rational-behavioral model abreast price estimation algorithm as a future research proposal. [ABSTRACT FROM AUTHOR]

This study deals with the development of a forensic version (EGS-F) of the Posttraumatic Stress Disorder (PTSD) Symptom Severity Scale according to DSM-5 criteria. The aim of this paper is intended to assess the symptoms severity of this mental disorder, as well as to detect probable malingering and symptom exaggeration among victims of gender violence in a forensic context. The sample consisted of 526 victims of sexual or family violence who sought therapy and 74 victims of the same kind who filed a complaint in court. Symptom severity was higher in victims assessed in the forensic context than in victims assessed in the clinical context. Items designed to detect probable malingering adequately discriminated between the two groups (t = 7.3, g = 0.97). A cut-off point of 2 in the subscale of malingering is appropriate to correctly classify the 74% of probable malingerers. This scale is useful for forensic assessment in victims of PTSD. [ABSTRACT FROM AUTHOR]

The dissociative identity disorder (DID) can be considered a rare disorder because of its seemingly low prevalence. However, in recent years it points to the possible underdiagnosis because its complexity and confusion at the time of differential diagnosis. On the other hand, the malingering of mental psychopathology can have a major socio-economic and legal impact, particularly important in this type of disorder, given the inability it generates and its complex diagnostic. This paper refers the case of a patient admitted to the short-term hospitalization unit of Dr. Rodríguez Lafora Hospital (Madrid) with depressive symptoms. Then the patient seemed to become a TID case. The evaluation consisted of a psychological history and the application of the Structured Inventory of Malingered Symptoms (SIMS) and the Millon Clinical Multiaxial Inventory (MCMI-II). The results showed an altered personality profile as well as likely malingered symptoms, what prevented us from a DID diagnosis. In view of the results, possible implications of this case for the clinical setting are discussed. [ABSTRACT FROM AUTHOR]

The article describes the design and implementation of the control system of the didactic thermal exchange plant - pit000, located in the center of electricity and industrial automation, ceai - sena, as an investigative contribution to the needs of the institutions of education and of companies, sugar mills, petrochemical and paper mills, among others. The control system is based on a cascade strategy temperature-flow, implemented through the use of instrumentation and industrial control technology, which includes intelligent flow and temperature transmitters, programmable logic controllers and control valves with smart positioner. The design method of the control system included the development of diagrams (p & id) and strategy blocks, the definition of conditions of operation of the process, the modeling of control loops by means of transfer functions, the design of the flow and temperature controllers, the determination of the tuning parameters making use of of matlab and the final implementation of the control system. The results of the research, which are associated with the implementation of the control system, are considered satisfactory, because they are validated with the simulation and test of the control strategy in the presence of operation, as well as the control strategy complied with the purpose of improving the behavior of temperature output of the product in the process. [ABSTRACT FROM AUTHOR]

This paper presents the results of a research project entitled "Simas Y FreeStyler: La Representacion Del Conocimiento Como Medio Para La Gestion Del Aprendizaje Autónomo "funded by the UNAD and UDI. It is assumed that the creation of learning communities among researchers, educators and students, supported by digital environments is an alternative for improving the quality of education and ensure the inclusion of IT. This paper presents the results of a descriptive research exercise which incorporates tools for the representation and evaluation in solving case studie by group of tenth grade students. The results show that there are effects of these tools on students' abilities to solve challenges commonly faced otherwise. It was noticed the Value that social networks can have when forming learning communities. [ABSTRACT FROM AUTHOR]

Designing and implementing collaboration strategies in supply chains contribute to global and local improvements of its members. This paper studies the impact of information sharing in a dyadic supply chain (one supplier and one manufacturer), each one with several available resources to schedule production orders. Various scheduling rules are proposed under dynamic environment that considers available information for decision-making. These methods are analyzed using discrete-event simulation models. An extended experimental study is carried out on a great number of well-known instances from the literature. Some intuitive statements are verified through the experiments about the importance of information sharing within the whole supply chain. One great contribution of this paper is the quantification of these benefits. Also, the experiments show other results that are not so much intuitive. For instance, this paper shows that there is no significant statistical difference between the best scheduling strategies for each collaboration scenario. This is mainly due to the fact that it is not always easy to know how and what type of information must be considered to be shared for the decision making process. [ABSTRACT FROM AUTHOR]

This paper presents the joint implementation of the simulation of operations and lines of balance, as tools that help to improve the efficiency in construction project planning, where the integration of these tools has been scarce in the national and international field. This paper expounds the simulation results of the activities associated with the construction works of structure, assembly and casting of walls and slab, in a multi-story building. The construction system is modeled, according to the way it is done by the company, and with the help of the lines of balance, generating two alternative scenarios in order to compare the times and the average costs of project completion. The first scenario takes advantage of the slack found in the current system in relation to the time of initiation of activities, without changing the amount of human resources and equipment. In second scenario, the amount of human resources is slightly increased, and the amount of forms for walls and slab increases by 25%. From the results, companies have a methodology for planning and selecting the appropriate scenario, according to their convenience. [ABSTRACT FROM AUTHOR]

In this paper the MADA mathematical model is presented for the optimal management of aquifer exploitation. The model is built by embedding the AQÜIMPE model for simulation of ground water aquifers into a linear programming algorithm. MADA is used to evaluate exploitation in «Cuenca Sur de la Habana» aquifer, following a given water use plan (PUA). It is shown in the paper that PUA distribution of well abstractions is not considering possible saline intrusion in the aquifer and to that end a solution is presented. [ABSTRACT FROM AUTHOR]

This paper describes the operational cycle of a workers' compensation insurer in Colombia. It explains the basic characteristics of complexity which are presented in systems like occupational risk, and proposes the use of system dynamics as an alternative to model those characteristics. The paper uses the causal loop diagrams to present the basic structure of the operational cycle model. We concluded that the operational cycle has important feedback cycles, time delays, and nonlinear relations that affect the understanding of the real system. Thus, the use of system thinking and formal simulation models are useful tools to understand and improve decisions in real systems. [ABSTRACT FROM AUTHOR]

Following Bobenrieth (2004) who establishes the importance that the commodity storage model has acquired in a growing number of theoretical and empirical papers, this article contributes with a study of the sensitivity of the estimated parameters and the implications that a more accurate method to estimate the harvest process's distribution would have, especially in the case when the size of the sample is increasing. Deaton and Laroque (1995, 1996) conclude that the commodity price model with rational expectations and competitive storage is unable to explain the high degree of autocorrelation of prices when the production process is independent and identically distributed (i.i.d.). Furthermore, the article written by Cafiero et al. (2009) concludes that when the accuracy of the estimation is improved by using a finer grid, the storage model explains the autocorrelation of prices in five of the thirteen commodities considered by Deaton and Laroque (1995, 1996). Additionally, if the model also considers the presence of a positive marginal cost of storage, Gustafson (1958) argues that the levels of autocorrelation in prices are explained for seven commodities. This paper estimates the storage model considering the Gauss-Hermite quadrature for the discretization of the distribution that characterizes the harvest, following the estimating methodology model of Cafiero et al. (2009) for annual data of real prices of sugar, in different time periods. The paper concludes that the use of Gauss-Hermite quadrature produces no significant changes in the magnitudes of the estimated parameters and the conclusion of Cafiero et al. (2009) for the model's ability to explain the autocorrelation of prices and profits is maintained, in all periods considered. [ABSTRACT FROM AUTHOR]

This paper assesses the possible impact of the new communication technologies on the operative performance of a generic supply chain. A simulation study has been accomplished in order to conceptualize the integration process that could take place in the supply chain, and to measure improvements in supply chain speed and flexibility as a consequence of a faster and shared information flow. The paper presents results for a system dynamics simulation model, whose basic structure was built from the beer game (Sterman 1984). The results show orders of magnitude of the improvements in terms of operational and financial metrics. [ABSTRACT FROM AUTHOR]

The objective of this paper is to show a methodology that allows finding the optimal behavior of a system, given a measure of effectiveness and a set of controllable variables. In the paper simulation techniques are combined with experimental design to produce a response surface, and after an optimization method is applied. A case study in the Cuban sugar industry is described. [ABSTRACT FROM AUTHOR]

In this paper a study of the production of liquefied petroleum gas is carried out in the Stabilization Unit refinery "Hermanos Díaz". Implementation of this process was conducted in the simulator Aspen Hysys 8.0 with the aim of developing a simulation that would increase the efficiency of this plant. Different alternatives are evaluated using the simulator tool Databook, as were the analysis of the temperature and pressure and its influence on the flow of the compounds of interest in the separators; the number of trays and the feed tray to the distillation column and its influence on the energy of the condenser and reboiler. It was determined that at 44°C and 160 kPa in the separator D-120 and at 34,5 °C and 738.8 kPa in the separator D-109 ensures good performance of the process. In addition it was found that with 50 trays and a feed tray 27 in the distillation tower T-104 guarantee lower consumption of energy (1,4*10 7 kJ/kmol and 1,5*107 kJ/kmol for the condenser and reboiler respectively). It was shown that an increased flow of unstabilized light naphtha fed to the plant, leads to increased efficiency of the unit. The simulation of the process led to raise the efficiency of the plant because the flow of liquefied petroleum gas increased in 11.79% to quality established. [ABSTRACT FROM AUTHOR]

Introduction. This paper introduces a proposal to improve the time of attention for patients, by means of the Lean Manufacturing methodology, in a gyneco-obstetrics emergency unit located in Bogotá, in which the patients have to wait for a long time and this fact goes against law 237, 2008, produced by the Colombian Senate. Objective. Develop an improvement proposal for the attention time, by the use of the Lean Manufacturing methodology, in the gyneco-obstetrics emergency unit of the ABC Clinic. Materials and methods. A field work was developed during six months, in which, by the use of Lean Manufacturing tools such as the value stream mapping and the spaghetti diagram and a study of times on a representative sample of patients, the areas and processes that do not add value to those patients were identified and, then, action plans to improve the attention times were generated. Results. The applicability of the proposal was assessed by means of simulations based on the Arena software, demonstrating improvements in the attention times of up to 56%. Conclusion. This project demonstrates the applicability of Lean Manufacturing and its main tools in clinics or hospital in Bogotá, contributing to establish what processes must be improved or eliminated in order to reduce the attention time for the patients. [ABSTRACT FROM AUTHOR]

The aim of this paper is to assess economic and biologic feasibility of different feed categories in swine prefattening and fattening. Equally important is to quantify the contribution of nutrients, digestible energy, and raw proteins based on conventional raw materials (corn and soybean), as well as non-conventional ones (parted rice, fat and sun flower meal). A composition analysis was made, and rations for pigs were simulated in the above-mentioned stages. According to the standard supplies, the protein levels found in the single-type feed were either excessive or deficient at times, in relation to the animal requirements. The costs of production were subsequently increased, and nutritional unbalances were observed, making feed rations costlier than the feeds made for the stages under the study, using non-conventional raw materials. [ABSTRACT FROM AUTHOR]

A productive system that shows shortcomings in its management of storage and material process can be represented with System Dynamics methodology, involving critical variables and generating sensitivity analysis according to different decision alternatives, which seek to improve their current productivity. This paper presents the results of researching work proposed for a small business which exposes lower total productivity levels and, through a simulation model can analyze different proposed decisions for improvement. [ABSTRACT FROM AUTHOR]

This research paper proposes a System Dynamics Model for Entrepreneurship Management, The Emprender Fund, which was constructed by the characterization of the value chain of the process using the tool SIPOC Dynamics Model Management Systems for Entrepreneurship, (Suppliers, Inputs, Process, Outputs and Costumers). A turn to the definition of the problem in structural terms, applied by an adaptation of the Causal Model to establish systemic interdependencies and feedback loops, enabling the construction of the model through the VENSIM tool (Ventana Systems Inc) used conceptually based Forrester Diagram. Also, it was calibrated with real data, performing simulations that determined that the main attributes that characterize the model of Emprender Fund are: the bankruptcy of enterprises, time spent by consultants to evaluate projects, and to a lesser extent, the number of business plans evaluated, since the proposed paradigm identifies both critical points of leverage as a dynamic model such as Entrepreneurship, becoming an important tool for management. [ABSTRACT FROM AUTHOR]

Control Engineering is the first subject taught to students of Electrical Engineering in the discipline of Electric Drive. It is focused on the study of the theory of continuous and discrete control, mainly for speed and position controlled drives. This subject constitutes the basis for the rest of discipline and it is characterized by a strong theoretical content. Simulation tools are very important for teaching this subject. In this paper, we expose an experience developed at the University of Camaguey and already applied in other Cuban and foreign universities. It consists on the creation and implementation of a virtual instrument for simulated and real laboratory practices. Sing it, students can corroborate simulated results and understand the relationships between abstract models and real controlled drive systems on their professional work. This virtual instrument is designed to facilitate the remote access to students, so they can test their results at any time from any computer with connectivity with the real laboratory equipment. To achieve the design goals and diversity of variants in the project presented to students, a simulated transfer function is introduced into the control loop. [ABSTRACT FROM AUTHOR]

In this paper, a simultaneous use of simulation and optimization techniques for the logistic operation planning is presented, specifically aimed to support the decision making processes related with fleet size determination in the supply--distribution process. The study is developed for a Cuban company dedicated to the transportation of goods and warehousing services. The implementation of the proposed tools enabled suggesting the optimal number of trucks to be used, considering minimization of the idle time of trucks and maximization of the customer service level. Experimental results show a significant improvement regarding the lead time reduction and the increment of order fulfillment for the customers of the company. [ABSTRACT FROM AUTHOR]

This paper presents the application of the Kanban methodology and analysis of the effect that this can generate in a manufacturing of distribution transformers. By applying the proposed methodology can be improved production scheduling, with the aim of reducing the amount of product in process is not used, so that inventory is reduced. To analyze the effect of applying the Kanban methodology in the company, the simulation technique was used, for which the current process and proposed to the rules of the Kanban methodology is modeled. From these results that yield modeling, it shows that there is an improvement in production lines where kanban methodology is used. [ABSTRACT FROM AUTHOR]

This paper presents a theoretical study on the multivariable control design for a wet grinding circuit. This design is intended to clarify some concepts and assumptions that are made when operating with the grinding circuits and in turn, is an approximation to the actual operation of a grinding circuit in the preparation of crude in the cement industry, considering what the most important variables of the process. The model from the grinding circuit is simulated to describe the dynamic behavior of two variables: particle size distribution (DTP) and moisture content. Through the dynamics of these variables is possible to discuss various aspects of the process, find the most sensitive variables, the main disturbance of the system and identify important dynamic to find a pairing that is capable of maintaining the system at the desired point of operation. Finally, we design a centralized controller is simulated to see how the behavior of the grinding circuit to sudden changes, both at the point of operation and in the process variables (feed flow of mineral, water flows and percentage of solids). [ABSTRACT FROM AUTHOR]

In this paper, the use of a multilayer perceptron (MLP) artificial neural network (ANN) is proposed to simulate the variation of protein concentration according to the time and also to determine the end and optimal conditions of the biodegradation process of wastewater from meat industry. To reduce the protein concentration, papains from Carica papaya latex have been used at controlled condition of pH (5 and 7) and temperature (25 and 30 °C). Results showed that a reduction of 82 to 91% of protein concentration by the action of papains for 30 to 40 h of process time. Simulations showed that the best condition of the process occurred at pH 5, 30 °C and 35 h, in which a maximum biodegradation of 91% was obtained. [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]

The paper presents a methodology to perform a simplified stochastic analysis of discrete linear structure responses under seismic actions. The structural dynamic response is determined in time domain by means of modal analysis, and the simplified stochastic analysis is performed by means of the Point Estimate Method. Structural system’s mass and stiffness are considered as independent stochastic variables. The development of an application example allows us illustrating the implementation of the proposed methodology. The results obtained with the Monte Carlo Simulation Method allow us to validate the methodology as well as to emphasize its advantages for practical purposes. [ABSTRACT FROM AUTHOR]