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

Copyright of Técnica Industrial: Revista Cuatrimestral de Ingeniería, Industria e Innovación is the property of Fundacion Tecnica Industrial and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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

In this work, butanol production by fermentation using a cyclic vacuum and multi fed-batch operations was evaluated through a process simulation strategy. The saccharification of the substrate, corn stover, was simulated in an integrated reactor with fermentation and in situ product recovery. Optimizations were carried out to achieve as objectives the maximum economic potential and the minimum electricity requirements of the heat-pump system needed for energy integration. Multi-objective optimizations were performed in MATLAB®. It was found that a cyclic vacuum was not required to achieve the maximum economic potential and that a multi-fed batch operating strategy is enough to obtain the maximum economic potential. Using these strategies, the electricity requirements were decreased by 5% and the economic potential was increased by 9% (~4 MM USD/year) when compared to a fed-batch reactor with in situ recovery using only one feed. [ABSTRACT FROM AUTHOR]

Introduction: The design of spread footings over a lime-treated soil is studied as an important topic in geotechnical and environmental engineering. With the emergence and use of algorithms, it is possible to solve optimization problems in engineering, leading, for example, to decreased amounts of materials, time, energy, and work. Objective: This research aims to optimize the CO2 emission and cost of building spread footings over a treated soil with hydrated lime using the modified simulated annealing algorithm (MSAA). Method: The parameters for shear strength (cohesion and friction angle) was calculated of a silty soil of the Guabirotuba geological formation of Curitiba (Brazil) stabilized with different lime contents (3, 5, 7 and 9%) at different curing times (30, 90, and 180 days). Then with these parameters, the geometry of the spread footings was optimized with MSAA minimizing the cost and CO2 emissions of their construction. For the design constraint of the structures the ultimate bearing capacity of the soil was used as criteria, the settlements produced by the service load, and the base safety factor Results: The results show that most of the problems converge to the same solution for costs and CO2 emissions without depending on curing time and lime content used, due to the solutions being restricted primarily by the maximum permissible settlements. Conclusions: With the increase in lime content, the cohesion of the mixtures increased for all curing times studied ant the friction angle had no major variations in relation to the amount of lime administered or to the curing time employed. Costs and carbon dioxide emissions for spread footing construction converge to the same results. In this sense, 9% lime can be avoided, and small percentages of lime (i.e. 3-5%) are appropriated to ground improvement and reduce the costs of this procedure. On the other hand, the MSAA can be designated as a robust algorithm due to having achieved almost equal results and, in some cases, better results compared with other algorithms to solve problems reported in the literature. [ABSTRACT FROM AUTHOR]

The work presented the multiobjective optimization of a cyclic cold work and aging treatment of an AISI 1045 steel. As a first step, regression models, for relating the technological variables and the micro-hardness parameters (i.e., the hardness increment and penetration), were fitted from an experimental study. The optimization was carried out by using an a posteriori approach, through the simple multiobjective cross entropy method. From the obtained solutions, the best option was chosen depending on the desired predefined conditions, analyzing several cases as possible practical situations. The work showed the effectiveness of the metaheuristic-based multiobjective optimization for selecting the best working parameters in the cyclic cold work and aging treatment, in order to obtain the most convenient microhardness profile. [ABSTRACT FROM AUTHOR]

Nowadays, autonomous systems that incorporate renewable energy sources and energy storage systems play a fundamental role as a solution to energy supply problems. These systems are a good alternative, mainly in remote areas of the electricity network such as islands. This paper analyzes the cost of battery life, operation and maintenance costs and the uncertainty costs associated with renewable energy agents for an autonomous microgrid developed on Dong-fushan Island in China, all in order to obtain the adequate parameters for the optimum operation of the same, without forgetting the characteristics of useful life in specific lead-acid batteries. It is intended, through the non-dominant algorithm of genetic classification (NSGA II), to achieve maximization of the aforementioned variables: useful life of the batteries, and the reduction of the generation cost, proposing a multi-objective optimization. In addition to the above, the costs of uncertainty associated with renewable wind energy are included. [ABSTRACT FROM AUTHOR]

The work presents research results obtained by the authors in the solution of optimal selection of renewable energy equipment task to meet the needs of a territory and each one of its parts from the offers available in the market and of the availability of energy resources in the territory. It is carried out a study of the existent research works, linked to the selection of energy installations, starting from those the antecedents settle down. A systemic analysis of the task is made, the conceptual mathematical model for the task, it complexity and the decomposition outline were determined for conditions close to the those that are present in the municipality of Ganda, Benguela province, Angola, taken as Study Case. [ABSTRACT FROM AUTHOR]

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

This paper reports the use of an orthogonal array for multi-objective optimization of the submerged arc welding process of JIS 3116 steel, by usingthe genetic algorithm based-method. Three process parameters were selected as independent variables: arc voltage, current intensity and welding speed. In addition, the geometric parameters of the welded joint were considered as constraints of the optimization problem. Two objective functions were selected: the deposition rate and dilution. Finally, the obtained outcomes were arranged in graphical form (Pareto's front) and analyzed to make the proper decision for different process preferences, allowing the comparison with the parameters used before the optimization task. [ABSTRACT FROM AUTHOR]

In this paper we study the Tranport Network Design Problem (TNDP). It consists in finding the ideal combination of routes and frequencies that allow the decision maker to balance the interests of the users and the transit operators, which are opposite. The TNDP uses as input a graph, with their transportation costs (in this case time), and the demands associated to each pair of nodes. Our proposed approach to solve the TNDP is based on a Variable Neighborhood Search (VNS) metaheuristic. VNS has been used to solve different kinds of combinatorial optimization problems and it consists in searching competitive solutions by iterative changes of the neighborhood. The VNS is tested first for the case study designed by Mandl, which consists in 15 nodes and 21 arcs, and a symmetric demand matrix. Posteriorly the VNS was tested for other 11 instances of (15, 30 and 45 nodes). In the first place, the model was run for that original case to compare it with other authors who worked this problem in the past. Then, we tested the VNS approach for a changing demand model in 3 moments of the day (Morning, afternoon and night) to prove the positive results obtained in the first exercise and give a greater scope to the problem solution. [ABSTRACT FROM AUTHOR]

This paper presents a model for the integrated Transmission and Generation Expansion Planning (TGEP). The main contribution of this paper lays in the use of the WTLR indexes (Weighted Transmission Loading Relief) for identifying new expansion candidates (lines and generators). The WTLR indexes are given as function of the distribution power factors and allow measuring the severity of overloads in normal conditions and under contingency (N-1 criterion). The applicability of the proposed model was tested in the IEEE RTS 24 bus power system. The TGEP was solved by means of the NSGA-II (Non-dominated Sorting Genetic Algorithm II) with the aim of minimizing costs and maximizing system security. The inclusion of generators as expansion alternatives reduces the number of necessary transmission lines in the expansion plan, especially when security criteria are taken into account. [ABSTRACT FROM AUTHOR]

Microgrids are a revolutionary concept to face some problems of the big and centralized power systems. Although emerging concept promises to offer numerous benefits, also presents new challenges in control and operation. One of the most important challenges is to make optimal power management into the microgrid. This power management must ensure maximum use of available resources; at same time it must reduce environmental contamination. Based on Multi-Objective Genetic Algorithm MOGA, this paper presents one strategy to make optimal power management in a grid-connected microgrid. The strategy runs over two conflictive objectives: to reduce microgrid operational cost and greenhouse emissions. Simulation results show benefits using the MOGA strategy, in comparison with a strategy of full importation from main grid. In this manner, the proposed strategy is a good option to build the optimizer kernel of energy management system EMS in microgrids. [ABSTRACT FROM AUTHOR]

The arc routing problem with a variable starting/ending position (Open Capacitated Arc Routing Problem - OCARP), in its classic version, pursues the best strategy to serve a set of customers located in the network arcs using vehicles. Compared to the Capacitated Arc Routing Problem (CARP), the OCARP lacks of constrains that guarantee that each vehicle ought to start and end the tour at a given vertex (also known as a depot). The aim of this paper is to propose a heuristic to find an efficient frontier for the main objective functions: minimize the number of vehicles and the total cost. Additionally, a hybrid algorithm that complements the genetic algorithm with artificial intelligence operator is proposed. [ABSTRACT FROM AUTHOR]

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

Copyright of Ingeniería (0121-750X) is the property of Ingenieria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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

This 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]

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

This paper presents a methodology for optimal relocation of transformers in distribution systems. The problem is formulated as an optimization model of multiobjective non-linear integer type, which considers investment and operating costs, and the benefit of the concept of assets to be recognized by usage charges as stipulated in Resolution CREG 097 of 2008. The model is solved using the multiobjective optimization algorithm NSGA II. To check the validity of the methodology, a real distribution system belonging to an electric utility in Colombia is used, which takes into account both single and three phase distribution transformers. The results compared with respect to the case without considering the relocation of distribution transformers, reflect the importance of this methodology and its benefits to the distribution companies, and serves as a support tool for compliance with the standards set by regulatory bodies that define the appropriate chargeability of distribution transformers. [ABSTRACT FROM AUTHOR]

This paper proposes a methodology based on decentralized operation and coordination of large power systems, obtaining the system's optimization in a simplified way, and reducing time consumption. The optimal search of generator voltage, tap changer and compensation, is accomplished by using an evolutionary technique, and considering the problem as a multi-objective optimization case. In this paper, both the decomposition network and the optimization problem are applied to two study cases (39 and 190 buses). Global optimal operation is attained, preserving the voltage stability and the exchanges among areas, with minimal operational information, simplicity in the equivalents and time consuming reduction. Results are similar to those obtained by a centralized optimization strategy. [ABSTRACT FROM AUTHOR]

Soil losses resulting from human activity have negative impacts in terms of loss of productivity and therefore income. In that sense, there is an overcost associated with the increased use of fertilizers as a result of the decrease of nutrients and organic carbon accumulation. The main objective of this paper is to develop a methodological tool to assess the optimal land use from an environmental and economic point of view. To observe potential variations of soil loss and potential economic benefits in the Negro river watershed, the Revised Universal Soil Loss Equation (RUSLE) methodology and economic valuation of market prices was used coupled with Geographic Information Systems (GIS) tool (ArcGIS 9.3). The obtained results with the GIS model are processed using multi-criteria evaluation techniques. Results show that land use in 2007, even though it represents greater economic benefit for farmers and peasants in the short term, it is not an economical and environmental optimal allocation in the long-term. [ABSTRACT FROM AUTHOR]

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

The scheduling problem is one of the most widely treated problems in literature; however, it is an NP hard complex problem. Also, when more than one objective is involved, this problem becomes one of the most complex ones in the field of operations research. A bio-objective model is then emerged for the Job-Shop Scheduling, including makespan and mean flow time. For solving the model a proposal which includes the use of Simulated Annealing (SA) metaheuristic and Pareto Approach. This model is evaluated in three problems described in literature with the following sizes: 6x6, 10x5 and 10x10. Results of the model are compared to other metaheuristics and it has been found that this model shows good results in the three problems evaluated. [ABSTRACT FROM AUTHOR]

This paper presents a methodology to solve the problem of distribution system planning, using a multi-objective optimization technique. In the proposed model the location and design of new elements and the upgrading of existing elements are considered. In the problem approach, investment and operation costs and network reliability are included in the objective function. This research topic is relevant to the electricity distribution companies, as it allows for new tools that bring the problem to real situations, such as considering multiple objectives, which has a positive impact on the finances and on operation of the system. In the model solution, an elitist non-dominated sorting algorithm (NSGA-II) is used, and to verify its efficiency a case of specialized literature is used, which corresponds to a distribution network of an electrical system. [ABSTRACT FROM AUTHOR]

This paper is devoted to the problem of allocating public funds to competing programs, projects or policies. Under a subjective approach, we apply multi-criteria analysis to define the concept of highest social portfolio return. This concept is modeled as the best compromise solution of a 0-1 multi-objective optimization problem. Often powerful metaheuristics are required for solving real size problems, but with many objectives evolutionary algorithms are also inefficient. Such difficulty is overcome using a new method which incorporates decision-maker's preferences to the evolutionary search. We used a model based on a binary fuzzy outranking relation provided by ELECTRE methods for multi-criteria decision making. The proposal is examined through real size problems, in which good solutions are reached; examples illustrating the case of basic research project portfolios and social action program portfolios are shown here. [ABSTRACT FROM AUTHOR]

This paper solves the optimization problem of communication networks by cable using a multi objective algorithm. The mathematical model is solved using a methodology based on the Non-dominated Sorting Algorithm (NSGAII). The mathematical model uses two objective functions, one is the investment costs and the other is an indicator related to the network operation. The problem solution is a Pareto front that consider information about the network design, showing a set of network configuration with minimum cost and minimum requirements of signal levels in the costumer connection nodes. For that, a real life test system is used. [ABSTRACT FROM AUTHOR]

In this paper, is defines a new and effective methodology based on intelligent agents for production sequencing Job Shop Environments; especially for small and medium enterprises in the metal mechanics sector, where these techniques have not been employed , due to the high resistance to change. This work is developed in two phases. In the first one, the different techniques used are defined. In the second step, statistical tests are executed in order to determine the approximation percentage solutions' to the optimal or sub optimal solution. This work's results show that the intelligent agents techniques don't produce an optimal result every single time; but in few seconds, these techniques, can find sub optimal solutions with an approximation of 97.81% and 90.43%, to the optimal or sub optimal solution, in the variables total time process and total idle time, respectively. This contrasts with the little effectiveness of traditional techniques. [ABSTRACT FROM AUTHOR]

Multicast plays an important role in supporting a new generation of applications. At present and for different reasons, technical and non-technical, multicast IP hasn't yet been totally adopted for Internet. During recent years, an active area of research is that of implementing this kind of traffic in the application layer where the multicast functionality isn't a responsibility of the routers but that of the hosts, which we know as Multicast Overlay Networks (MON). In this article, routing in an MON is put forward as a multiobjective optimization problem (MOP) where two functions are optimized: 1) the total end to end delay of the multicast tree and 2) the maximum link utilization. The simultaneous optimization of these two functions is an NP-Complete problem and to solve this we suggest using Multiobjective Evolutionary Algorithms (MOEA), specifically NSGA-II. [ABSTRACT FROM AUTHOR]

This work deals with the combination problem of generating and optimizing technologically feasible assembly sequences and process planning involving tools and work places. The assembly sequences and related technological decisions are obtained from a 3D model of the assembled parts based on mating conditions along with a set of technological criteria, which allows automatically analyzing and generating the sequences. The generated assembly sequences are pre-processed and optimized for the assembly Process Planning using Genetic Algorithms. This approach integrates the geometric and technological information of the assembly process, which allows reducing the number of elements and sequences to be processed with the consequent processing time and cost reduction. [ABSTRACT FROM AUTHOR]

In this paper, we develop a fuzzy analytical model, which solves a multiobjective problem in multicast transmission with static trees over GMPLS networks. A model proponed by Donoso [4] was used. The multiobjective problem is solved through metaheuristic wit h evolutionary algorithms, in this case SPEA2 solving a NP-Hard problem in polynomial time. Additionally, a Fuzzy Evolutionary Algorithm based on SPEA2 is implemented. Finally, the comparison between FSPEA2 and SPEA2 is realized and we are giving some conclusions. [ABSTRACT FROM AUTHOR]

In this paper, an analysis of evolutionary algorithms for multi objective optimization, Non-dominated Sorting Genetic Algorithm (NSGA-II) and Strength Pareto Evolutionary Algorithm (SPEA-II) is presented. For this analysis, is taken as reference an optimization problem in a multicast data network, which has as objective functions the hop count and transmission delay. The algorithms performance is compared in tree different networks. Moreover, the model for two of this topologies using GAMS tool is resolved and results are compared with the NSGA-II and SPEA-II algorithms proposed. Problem results show the algorithms performance in their solution. [ABSTRACT FROM AUTHOR]

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