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An important part of the structural design process is to decrease the effect of vibration in buildings, particularly those that may be subject to seismic excitation. Although research in the field of structural control has been made since the early 1900s, the complexity and dimensions of civil structures make this problem particularly difficult to solve due to the high demand for control effort and many other associated limitations. This paper analyzes the performance of a novel passive control system that can be used for vibration control in civil structures subjected to base excitation. This control device is called Tuned Inerter Damper (TID), which overcomes the limitation of classic passive devices that are efficient in a narrow frequency band for which they are tuned, a situation that is inconvenient since earthquakes exhibit a very diverse frequency content on most occasions. Besides, this study employs a metaheuristic optimization approach based on the differential evolution method (DE) combined with an elastic time-history dynamic analysis, through which the vibration control focuses on two individual objectives: first, minimizing the maximum horizontal displacement; and second, minimizing the root mean square (RMS) response of displacements. A 12-story building equipped with a novel arrangement of the TID, and subjected to multiple seismic excitations is studied to verify the effectiveness of the device. The results show a significant enhancement in the dynamic response when the arrangement presented in this work is used, and considerably better than an equivalent TMD. Therefore, TID represents a potentially attractive alternative to traditional passive control techniques. [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 proposes an alternative methodology to optimally design an electrical distribution system in a real urban area. A medium voltage (MV) network polygon is extracted from the web page of a distribution company (GIS platform), which serves as a comparison pattern. A redesign of the medium voltage network is made to the extracted polygon. Taking as a premise that it is a new urbanization that needs to be provided with electric power, with all the technical requirements imposed by the regulating entity, good power quality and at minimum cost. To achieve this goal, two mathematical optimization models are used. The methodology begins by delimiting the project area in a geo-referenced manner; in this area 36 possible sites are located where the distribution transformers that will provide electricity to the new urbanization can be placed. The first optimization model determines how many transformers will be installed, by means of a minimization objective function, the constraints of the model are: transformer capacity (KVA) and coverage (number of subscribers connected to the low voltage network of each transformer). Once the number of transformers to be installed and their respective geo-referenced optimal locations are determined, the model is run. The second heuristic optimization model, based on graph theory, calculates the mine spanning tree for the connection of the medium voltage electrical network, thus interconnecting the transformers of the project with the minimum distance, thus optimizing the construction cost. These optimization models are implemented and solved with Matlab and LpSolve software. The topology found with the two proposed models is electrically evaluated by running power flows with CYMEDIST software. Finally, the proposed model is evaluated by comparing the electrical parameters obtained with the electrical parameters of the polygon extracted from the GIS system of the distribution company. [ABSTRACT FROM AUTHOR]

The objective of fringe pattern analysis is to extract modulated experimental information in an image. Among the techniques used in the demodulation process is the Regularized Phase Tracking. In this technique, a functional is proposed which is usually solved with classical minimization methods. This paper presents a minimization method for this technique using the fixed-point technique, which presents a normalized error like classical minimization methods, but with a notable reduction in processing time. [ABSTRACT FROM AUTHOR]

This document presents in detail the mathematical formulation of the second renewable energy auction in Colombia, used for the allocation of long-term energy contracts, which was carried out through a double-sided auction, defined in Resolutions 4-0590 and 4-0591 of 2019 from the UPME. The mixed integer linear programming model developed in this paper solves an optimization problem that seeks the combination of offers that maximizes the benefit of the consumer, subject to operational and economic constraints proposed by regulatory mechanisms. The effectiveness of the algorithm developed in Python was tested by validating it with real data, obtaining the same results published by UPME. [ABSTRACT FROM AUTHOR]

Introduction-- A mathematical model for flexible electrical loads and energy storage system scheduling is presented in this paper, leveraged by the hourly rates according to resolution CREG 015/2018 and analyzed at the residential sector in the context of new demand curves resulting from measures against the COVID-19 pandemic. Objectives-- Three mathematical optimization models are proposed, aiming to find the lowest billing cost for the end-user through flexible load characteristics and seeking optimization through mixed-integer linear programming models. Methodology-- For the calculation of hourly rates, the mathematical formulation described in resolution CREG 015 is implemented and hourly rates are obtained in three different levels following a logic similar to the demand response schemes called Time of Use. Results-- The results obtained show that a demand response program with hourly rates effectively introduces an economic incentive during the evaluated period, through the possibility of modifying consumption patterns that reduce the payment of the electricity bill. Conclusions-- The proposed model of energy demand through scheduling selected flexible loads model and the opportunity to use the energy stored in electric vehicles generates economic benefits for the user by minimizing the cost of energy during the teleworking period in COVID-19 pandemic. [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]

After a large-scale blackout power system restoration must be accomplished as soon as possible. For this, the generation must be initially restored, then, the transmission system, and finally the load pick up must be completed. To obtain a faster restoration process, it is necessary to establish start-up methodologies for generating units that first start those units that provide black start, and then take the starting power to other generation units without this characteristic, by means of a feasible transmission route. This paper presents a review of different methodologies of optimal generation start-up for power system restoration reported in the scientific literature taking into account the integration of non-conventional renewable energy sources. Within this review it is highlighted that heuristic methods, despite of being effective, are not used in real-time operation due to their high computational cost. [ABSTRACT FROM AUTHOR]

Proper management of projects has become an element of vital importance for the solution to problems of society. In this context, there are two main objectives to be solved: the construction of project plans which may comply with the constraints of the problem and the optimization in terms of cost and time of those plans. To this end, all activities of project must be organized in such way that the constraints related to the precedence among them and the availability of renewable and non-renewable resources at each instant of time are met. The aim of this paper is to present an Estimation of Distribution Algorithm (EDA), which incorporates the handling of the constraints in the probabilistic model, for the construction of optimal or quasi-optimal project plans. For the validation of the algorithm, authors used both the PSPLib database repository for the development of the scheduling research and the databases of projects of the Repository for Research in Project Management, University of Infomatic Sciences. [ABSTRACT FROM AUTHOR]

The agave is a source nontimber species, which can be used for the extraction of cellulose. Work has been done reporting papermaking fibers from six species of agaves: A. lechuguilla, A. angustifolia, A. tequilana, A. American., A. mapisaga and A. salmiana using different methods for extraction fiber. Their results indicate that A. mapisaga and A. salmiana were the species that showed better characteristics for the possible development of paper. In this paper we sought to create a new value added to the waste leaves Agaváceas agribusiness processing of pulque, from A. salmiana B. Otto ex Salm. Pulp was obtained by two methods: alkaline pulping method known as Organosolv. Characteristics and efficiencies of the processes under an optimization study were evaluated. As a result, it is concluded that optimal and reproducible for cellulose pulp by alkaline pulping A.salmiana conditions were: [NaOH] 12%; 24 hours; [Na2CO3] 2.5% and [Na2SO4] 0.2%. In contrast to the acid pulping optimum conditions they were: 60% H2O; 6 hours; [CH3COOH] and 80% [HCl] 0.5%. On the basis of response analysis "more better performance" in the ANOVA, we found that for the alkaline pulping, the factor having the greatest impact on the process is time and the factor that has lower incidence [Na2CO3]; on the other hand, for acid pulping the factor having the greatest contribution it is [CH3COOH] and the lowest incidence is the stirring rate. In the alkaline pulping confirmatory experiments yield 39.69% cellulose pulp A.salmianawas obtained whereas for organosolv pulping yield 71.57% was obtained. [ABSTRACT FROM AUTHOR]

This paper analyze the most significant studies done globally of the efficiency measurement on higher education institutions (IES in Spanish), which for this purpose use Data Envelopment Analysis. Within each study the characteristics considered are: selected model, model guidance, inputs and outputs, main findings, conclusions and the use of a complementary method. Models and characteristics studied in the papers are statistically analyzed, highlighting patterns used by most authors. Results are expected to be useful to provide a basis for future research on how to assess the efficiency measurement and productivity indices through this methodology. As a conclusion, DEA has been extensively used to measure the efficiency of education globally, 254 input variables were identified and divided into four categories and 230 output variables were identified and grouped into three categories for analysis. [ABSTRACT FROM AUTHOR]

This paper presents an optimization procedure for identifying the minimum cost of water pipe networks considering a table of commercial diameters. To this end, a real-coding Genetic Algorithm (GA) with the use of a simulated binary and convex crossover and mutation per variable; as well as a dynamic penalty strategy was developed. A computer program to solve the hydraulic model based on the Newton-Raphson method was developed for calculating the head loss using Hazen-Williams (HW) and Colebrook correlations. By analyzing a benchmark pipe network example, it is shown that different results are obtained by the HW and Colebrook correlations. Moreover, when simulating the best HW pipe network configuration with the Colebrook correlation, some constraints of the design are violated, indicating that the Colebrook formulation is more adequate to be used in conjunction with the GA due to the randomness of the GA with respect to the Reynolds numbers. [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]

The flow shop scheduling is a classic problem of production scheduling. The first scientific publications on production scheduling appeared more than half a century ago. However, many authors have recognized a gap between the specialized literature and the real environment problems. In this paper, the flow shop is modeled taking into account preparation time machines, setup-time between two jobs, precedence between jobs, the possibility to skip stages and as objective function minimizing the total processing time or make span. At this moment, there are no computational methods that can solve this problem taking into account all the mentioned elements. The Reinforcement Learning approach known as Q-Learning was adapted to use it in the solution of this problem. Finally, the algorithm was tested with problems of different levels of complexity in order to obtain satisfactory results in terms of solutions quality. [ABSTRACT FROM AUTHOR]

A container terminal is a source of dissimilar math problems and computational nature thus. In particular stacking of containers on the yard of a maritime terminal is one of the most important operations, mainly due to bottlenecks that arise therein, with the respective defaults efficiency indicators. Container stacking is divided into operations of loading, unloading and premarshalling. When these activities are performed operators and managers must determine the exact positions for containers, download or reposition making efficient use of available storage space, reducing unproductive movements and transportation costs, etc. The purpose of this paper is to review and describe objective functions found in the literature on optimization problems that arise during the stacking of containers operations. The analyzed objective functions are grouped into two basic classes: minimize unproductive movements yard cranes and minimize cost of transportation of containers during stacking. Finally, we discuss different items that could be considered as further research lines for mathematical modeling in container stacking optimization problems. [ABSTRACT FROM AUTHOR]

The aim of this paper is to propose a procedure to create escape vectors specifically developed to perform an orthogonal projection from an Ax≤b type polyhedron's edge to its interior. The proposed procedure can be implemented in interior-point methods for solving linear programming problems since in these methods various strategies are used to avoid reaching the borders of the polyhedron. A projection procedure was developed to the polyhedron's interior starting from three scenarios and it was used on a context case demonstrating its applicability. The results show that the projection carried out in the iteration in which the escape is done not only allows abandoning from a suboptimal solution but it also kept the same objective function value. Therefore, it can be concluded that interior-point methods do not need to avoid the frontier or to adjust values, as it occurs in other applications. [ABSTRACT FROM AUTHOR]

This paper presents a study done to find an interior point in the feasible region of linear programming problems is an aspect that should be solved in the initial stage of the implementation of the interior point algorithms used to optimize them. Consequently, it is proposed a methodology that starts with a formulation that does not require adding surplus or slack variables. It only includes an additional variable to generate a polyhedron in a new expanded space and with simple projections finds an interior point in the same polyhedron. It is demonstrated that the optimal solution of the extended linear programming problem allows obtaining a feasible point of the original problem or concluding that it has no feasible solutions. [ABSTRACT FROM AUTHOR]

This paper optimizes the cost of deployment of universal data aggregation points (UDAP) for advanced smart metering infrastructure (AMI), considering coverage and capacity. We propose a routing model between UDAPs, based on minimum spanning tree algorithm (MST) to find the minimum number of links in a specific geo-referenced area. Because it is geo-referenced, the location of the UDAP and the topology of the net are real. The search for optimal locations of a set of candidate sites warns the necessity of an optimization algorithm to minimize candidate sites and turn them into active feasible sites in the previous design to the network deployment. Results imply a strong base point for electricity distribution companies to establish the right number of concentrators (UDAP). There are certain applied AMI communication technologies considered, such as: cellular networks (CDMA, GPRS, and LTE) or the IEEE 802.15.4 g standard. The lowest cost based on the optimal resources usage in infrastructure deployment is very important for planning and scalability phases of AMI network. [ABSTRACT FROM AUTHOR]

The aim of this paper was to obtain a dehydrated product by spray drying of orange juice concentrate, with good acceptability, for using as flavoring. With the aid of response surface methodology a 32 factorial model was used for the optimization of the air inlet temperature and maltodextrin content. Maltodextrin DE 12 (juice/support solids w/w ratio of 1:1.5, 1:2.08 and 1:3, respectively) was used as support. Yield, ascorbic acid retention, moisture and rehydration were used as response variables. Yield and ascorbic acid retention were maximized, while moisture and rehydration were minimized to calculate the optimal values. An optimal point was obtained at the air inlet temperature de 155 °C and 74 % w/w maltodextrin content. Using this combination a product with 77 % yield, 3.8 % moisture, 89.6 % ascorbic acid retention, 64 s for rehydration and 10 μm particle mean diameter. The dehydrated product had a good quality for using as flavoring. [ABSTRACT FROM AUTHOR]

Inside the process of optical design, the diffusion phenomenon is usually set apart until the final stage: the study of tolerances. So, its influence is evaluated considering the whole of the system after having designed it taking into account all other parameters. The phenomenon of diffusion is relevant in many optical designs and its influence can determine the final design. So, this procedure, relegating diffusion to stage study, does not means that its influence over the system isn't heavy, but stems from the high computational cost of considering it on earlier stages. But there is a way to include it before the tolerances study stage by using a dual optimization process with an on/off mechanism. Thus the best system configuration is obtained considering the diffusion. In order to reduce the computation time we adjust dynamically the values of the diffuser model control parameters. The number of re-emitters is one of these strategic control parameters, inside this parameter are included two different values, the number of reemitting focus and the number of reemitting rays considered. Varying this value, different degrees of model accuracy can be obtained, allowing to adapt the model accuracy depending on the merit function instantaneous value. In this paper we analyse the use of a diffuser model, varying the parameter of the number of reemitters, and its influence on optical system computer aided design (CAD). We make so by employing a simple system consisting on a light source, a biconvex lens, on which the diffusion model is applied only on the second surface, and a detection display. [ABSTRACT FROM AUTHOR]

This paper proposes the identification parameter for a human migration model among five Colombian regions. For the identification of parameters an optimization approach is employed where we propose two objective functions. The results obtained with the objective functions are statistically analyzed. The methodology for data analysis employs parametric or non-parametric tests depending on the fulfillment of the assumptions of normality and homoscedasticity (equal variance). To adjust the model, two approaches to the objective function are used. The first considers the total number of population and the second uses the number of inhabitants in each region. By carrying out statistical analyzes, a better adjustment model is observed when considering the number of inhabitants in each region. [ABSTRACT FROM AUTHOR]

This paper presents a literature survey of the current state of the art in vehicle relocation problems applied to EMS. Specially, we focus on describing a classification of this kind of problems, main components that should be taken into account for modeling them, key methods used for solving these problems, objectives pursued by the researchers, key performance measures considered in the EMS literature, software used in the development of models, data collection and verification and validation of the models. We also present some of the relocation policies that have been most frequently evaluated and implemented. [ABSTRACT FROM AUTHOR]

This paper presents an optimal budget assignment model for improving quality service in distribution systems. The model consists on a multi objective problem which aims at minimizing maintenance costs in distribution systems while maximizing the reduction of faults rate. This last objective is measured through the SAIFI indicator (System Average Interruption Frequency Index). To solve the proposed model two algorithms were implemented: NSGAII (Non-Dominated Sorting Genetic Algorithm II) and a Memetic Algorithm. Several tests were performed with two real electrical systems of 100 and 200 nodes in the Department of Antioquia in Colombia, showing the applicability of the proposed approach. The optimal Pareto fronts obtained in the problem solution show a set of available options that represent a trade-off between both objectives and provides the system operator with an estimate of how much to invest in maintenance to achieve a desired value of the SAIFI indicator. [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]

The main objective of this paper is to analyze the importance of strategic planning applied to Colombian mining. This research was performed the literature review and case studies of countries that have implemented a method that seeks continuous improvement of processes and making sound decisions mining companies based on factors that were not taken into account previously. We selected two investigations, one applied to surface mining and underground mining other, showing significant progress in using strategic planning as a means to an ongoing development. Each case is unique but can be applied anywhere in the world depending on the characteristics of the areas where the project will take place, also emphasizes the current framework of strategic planning and trends that this methodology presents a future in mining Colombia where intervention is necessary to achieve ideological and procedural significant development within the industries of the continent, it shows the lack of new methodologies and best in business investment from the country's mining mining institutions to mining companies. [ABSTRACT FROM AUTHOR]

The challenge of using renewable energy sources means that the production of biofuels and the design of their supply chains, should be pursue environmental and social benefits beyond the purely economic benefit. In this paper are revised some discussions about the impact of biofuels on sustainability and researching in the biofuel supply chains design of first and second generation via mathematical optimization, to analyze how environmental and social concerns have been considered in this problem. Finally, techniques most used optimization were identified and the review found that the concept of sustainability in the design of biofuel supply chains through modeling, is just beginning. [ABSTRACT FROM AUTHOR]

The purpose of this paper was to design a procedure for the scheduling and manufacturing control of a small shoe business located in the city of San Jose de Cucuta. The scheduling was done applying the theory of constraints, together with the operations research, specifically the linear programming technique. The system constraints were identified to develop a mathematical model that determined the optimal quantities of manufacturing, maximizing the throughput (profits, or selling price minus cost of materials)for a certain period. From the mathematical model a procedure for the scheduling and manufacturing control of a small shoe business was made, which was validated by hypothesis testing, comparing real manufacturing data during the period of study with the actual procedure and the planning data from the proposed procedure, obtaining as a result that the procedure designed can achieve a higher throughput, reducing inventory costs and delivery times, managing to meet the demand in full. This procedure could be implemented in small shoe businesses that have the same characteristics of the case study. [ABSTRACT FROM AUTHOR]

Shell and tube heat exchangers are ones the most important equipment in the industry. Their thermodynamic design is based on the global heat transference coefficient and the pressure drop. In 2007 was settled a new thermodynamic property denominated "Entransy", which expresses the capacity of a body to transfer heat. The loss of this capacity is denominated "Entransy Dissipation". For evaluating the ecological impact of thermal machines, Angulo-Brown created in 1991 the "ecological function". In this paper the"entransy dissipation" and the ecological function were combined and a new expression for evaluating the ecological impact of shell and tube heat exchangers was created. A multi-objective optimization of this equipment wasalso realized. The ecological function and the cost wereused as objective functions. For carry out the optimization the method of the Genetic Algorithms was used. [ABSTRACT FROM AUTHOR]

This paper summarizes the contributions of a PhD focused on developing a set of numerical methods for the analysis of periodic diffractive optical devices such as holographic diffractive devices, thin film filters or diffraction gratings. For the rigorous and comprehensive analysis of these devices in optical wavelengths the finite difference time domain (DFDT) method was considered being compared to classical theories. Application of DFDT in optical wavelengths implies a considerable computational cost. Therefore, this method was accelerated for the most common computing platforms: CPU (Central Processing Unit) and GPU (Graphic Processing Unit). [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]

This paper analyzes the effect of different configurations of initial conditions for the optimization algorithm based on particle swarms with vorticity behavior. The proposed algorithm combines the gradient-based search and particle swarm behavior, thus, this algorithm can be affected by the initial conditions for the particles. Finally, a 2D test function is used to observe the characteristics of the algorithm. [ABSTRACT FROM AUTHOR]