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Author Alvarez-Miranda, E.; Pereira, J.
Title (up) A Districting Application with a Quality of Service Objective Type
Year 2022 Publication Mathematics Abbreviated Journal Mathematics
Volume 10 Issue 1 Pages 13
Keywords districtin; glast-mile delivery; hybrid heuristics
Abstract E-commerce sales have led to a considerable increase in the demand for last-mile delivery companies, revealing several problems in their logistics processes. Among these problems, are not meeting delivery deadlines. For example, in Chile, the national consumer service (SERNAC) indicated that in 2018, late deliveries represented 23% of complaints in retail online sales and were the second most common reason for complaints. Some of the causes are incorrectly designed delivery zones because in many cases, these delivery zones do not account for the demographic growth of cities. The result is an imbalanced workload between different zones, which leads to some resources being idle while others fail to meet their workload in satisfactory conditions. The present work proposes a hybrid method for designing delivery zones with an objective based on improving the quality of express delivery services. The proposed method combines a preprocess based on the grouping of demand in areas according to the structure of the territory, a heuristic that generates multiple candidates for the distribution zones, and a mathematical model that combines the different distribution zones generated to obtain a final territorial design. To verify the applicability of the proposed method, a case study is considered based on the real situation of a Chilean courier company with low service fulfillment in its express deliveries. The results obtained from the computational experiments show the applicability of the method, highlighting the validity of the aggregation procedure and improvements in the results obtained using the hybrid method compared to the initial heuristic. The final solution improves the ability to meet the conditions associated with express deliveries, compared with the current situation, by 12 percentage points. The results also allow an indicative sample of the critical service factors of a company to be obtained, identifying the effects of possible changes in demand or service conditions
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2227-7390 ISBN Medium
Area Expedition Conference
Notes WOS:000751158600001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1529
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Author Alvarez-Miranda, E.; Pereira, J.; Torrez-Meruvia H.; Vila, M.
Title (up) A Hybrid Genetic Algorithm for the Simple Assembly Line Balancing Problem with a Fixed Number of Workstations Type
Year 2021 Publication Mathematics Abbreviated Journal Mathematics
Volume 9 Issue 17 Pages 2157
Keywords assembly lines; manufacturing; line balancing; hybrid genetic algorithm
Abstract The assembly line balancing problem is a classical optimisation problem whose objective is to assign each production task to one of the stations on the assembly line so that the total efficiency of the line is maximized. This study proposes a novel hybrid method to solve the simple version of the problem in which the number of stations is fixed, a problem known as SALBP-2. The hybrid differs from previous approaches by encoding individuals of a genetic algorithm as instances of a modified problem that contains only a subset of the solutions to the original formulation. These individuals are decoded to feasible solutions of the original problem during fitness evaluation in which the resolution of the modified problem is conducted using a dynamic programming based approach that uses new bounds to reduce its state space. Computational experiments show the efficiency of the method as it is able to obtain several new best-known solutions for some of the benchmark instances used in the literature for comparison purposes.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2227-7390 ISBN Medium
Area Expedition Conference
Notes WOS:000694360700001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1466
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Author Moreno, S.; Pereira, J.; Yushimito, W.
Title (up) A hybrid K-means and integer programming method for commercial territory design: a case study in meat distribution Type
Year 2020 Publication Annals Of Operations Research Abbreviated Journal Ann. Oper. Res.
Volume 286 Issue 1-2 Pages 87-117
Keywords Territorial design; Clustering; K-means; Integer programming; Case study
Abstract The objective of territorial design for a distribution company is the definition of geographic areas that group customers. These geographic areas, usually called districts or territories, should comply with operational rules while maximizing potential sales and minimizing incurred costs. Consequently, territorial design can be seen as a clustering problem in which clients are geographically grouped according to certain criteria which usually vary according to specific objectives and requirements (e.g. costs, delivery times, workload, number of clients, etc.). In this work, we provide a novel hybrid approach for territorial design by means of combining a K-means-based approach for clustering construction with an optimization framework. The K-means approach incorporates the novelty of using tour length approximation techniques to satisfy the conditions of a pork and poultry distributor based in the region of Valparaiso in Chile. The resulting method proves to be robust in the experiments performed, and the Valparaiso case study shows significant savings when compared to the original solution used by the company.
Address [Moreno, Sebastian; Pereira, Jordi; Yushimito, Wilfredo] Univ Adolfo Ibanez, Fac Engn & Sci, Av Padre Hurtado 750, Vina Del Mar, Chile, Email: sebastian.moreno@uai.cl;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0254-5330 ISBN Medium
Area Expedition Conference
Notes WOS:000511564300005 Approved
Call Number UAI @ eduardo.moreno @ Serial 1105
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Author Pereira, J.; Ritt, M.; Vasquez, O.C.
Title (up) A memetic algorithm for the cost-oriented robotic assembly line balancing problem Type
Year 2018 Publication Computers & Operations Research Abbreviated Journal Comput. Oper. Res.
Volume 99 Issue Pages 249-261
Keywords Line balancing; Cost-oriented line balancing; Robotic assembly line; Hybrid algorithms
Abstract In order to minimize costs, manufacturing companies have been relying on assembly lines for the mass production of commodity goods. Among other issues, the successful operation of an assembly line requires balancing work among the stations of the line in order to maximize its efficiency, a problem known in the literature as the assembly line balancing problem, ALBP. In this work, we consider an ALBP in which task assignment and equipment decisions are jointly considered, a problem that has been denoted as the robotic ALBP. Moreover, we focus on the case in which equipment has different costs, leading to a cost-oriented formulation. In order to solve the problem, which we denote as the cost-oriented robotic assembly line balancing problem, cRALBP, a hybrid metaheuristic is proposed. The metaheuristic embeds results obtained for two special cases of the problem within a genetic algorithm in order to obtain a memetic algorithm, applicable to the general problem. An extensive computational experiment shows the advantages of the hybrid approach and how each of the components of the algorithm contributes to the overall ability of the method to obtain good solutions. (C) 2018 Elsevier Ltd. All rights reserved.
Address [Pereira, Jordi] Univ Adolfo Ibanez, Fac Engn & Sci, Av Padre Hurtado 750,Off C216, Vina Del Mar, Chile, Email: jorge.pereira@uai.cl;
Corporate Author Thesis
Publisher Pergamon-Elsevier Science Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0305-0548 ISBN Medium
Area Expedition Conference
Notes WOS:000442059400019 Approved
Call Number UAI @ eduardo.moreno @ Serial 907
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Author Alvarez-Miranda, E.; Campos-Valdes, C.; Quiroga, M.M.; Moreno-Faguett, M.; Pereira, J.
Title (up) A Multi-Criteria Pen for Drawing Fair Districts: When Democratic and Demographic Fairness Matter Type
Year 2020 Publication Mathematics Abbreviated Journal Mathematics
Volume 8 Issue 9 Pages 27 pp
Keywords multi-criteria optimization; OR applications; malapportionment; districting; electoral system
Abstract Electoral systems are modified by individuals who have incentives to bias the rules for their political advantage (i.e., gerrymandering). To prevent gerrymandering, legislative institutions can rely on mathematical tools to guarantee democratic fairness and territorial contiguity. These tools have been successfully used in the past; however, there is a need to accommodate additional meanings of the term fairness within the electoral systems of modern democracies. In this paper, we present an optimization framework that considers multiple criteria for drawing districts and assigning the number of representatives. Besides some typical districting criteria (malapportionment and contiguity), we introduce novel criteria for ensuring territorial equilibrium and incentives for candidates to deploy their representation efforts fairly during their campaign and period in office. We test the method, which we denote as Multi-criteria Pen, in a recent and a forthcoming reform of the Chilean electoral system. The results show the potential of our tool to improve the current territorial design and offers insights on the motivations, objectives, and deficiencies of both reform plans.
Address [Alvarez-Miranda, Eduardo; Moreno-Faguett, Magas] Univ Talca, Fac Engn, Dept Ind Engn, Campus Curico, Curico 3341717, Chile, Email: ealvarez@utalca.cl;
Corporate Author Thesis
Publisher Mdpi Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2227-7390 ISBN Medium
Area Expedition Conference
Notes WOS:000580771600001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1246
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Author Pereira, J.; Vila, M.
Title (up) A new model for supply chain network design with integrated assembly line balancing decisions Type
Year 2016 Publication International Journal Of Production Research Abbreviated Journal Int. J. Prod. Res.
Volume 54 Issue 9 Pages 2653-2669
Keywords decomposition; mixed integer linear programming; supply chain design; line balancing; SALBP-1
Abstract Supply chain network design aims at the integration of the different actors of a supply chain within a single framework in order to optimise the total profit of the system. In this paper, we consider the integration of line balancing issues within the tactical decisions of the supply chain, and we offer a novel model and a solution approach for the problem. The new approach decomposes the problem into multiple line balancing problems and a mixed integer linear model, which is easier to solve than the previously available non-linear mixed integer formulation. The results show that the new method is able to solve previously studied models within a fraction of the reported running times, and also allows us to solve larger instances than those reported in earlier works. Finally, we also provide some analysis on the influence of the cost structure, the demand and the structure of the assembly process on the final configuration of the assemblies and the distribution network.
Address [Pereira, Jordi] Univ Adolfo Ibanez, Fac Sci & Engn, Vina Del Mar, Chile, Email: jorge.pereira@uai.cl
Corporate Author Thesis
Publisher Taylor & Francis Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-7543 ISBN Medium
Area Expedition Conference
Notes WOS:000373632300009 Approved
Call Number UAI @ eduardo.moreno @ Serial 608
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Author Pereira, J.; Ritt, M
Title (up) A note on “Algorithms for the Calzedonia workload allocation problem” Type
Year 2022 Publication Journal of the Operational Research Society Abbreviated Journal J. Oper. Res. Soc.
Volume 73 Issue 6 Pages 1420-1422
Keywords Assembly line balancing; worker allocation; dynamic programming
Abstract Battarra et al. recently proposed a novel assembly line balancing problem with applications to the apparel industry, where the tasks are performed in a fixed order. To solve the problem, one has to assign workers and tasks to the workstations with the objective of maximising the throughput of the assembly line. In this paper, we provide dynamic programming formulations for the general problem and some special cases. We then use these formulations to develop an exact solution approach that optimally solves the instances in Battarra et al. within seconds.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0160-5682 ISBN Medium
Area Expedition Conference
Notes WOS:000627308200001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1351
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Author Cohen, Y.M.; Keskinocak, P.; Pereira, J.
Title (up) A note on the flowtime network restoration problem Type
Year 2021 Publication IISE Transactions Abbreviated Journal IISE Trans.
Volume 53 Issue 12 Pages 1351-1352
Keywords Scheduling; network construction planning; emergency restoration operations; deliveryman problem; traveling repairman problem
Abstract The flowtime network restoration problem was introduced by Averbakh and Pereira (2012) who presented a Minimum Spanning Tree heuristic, two local search procedures, and an exact branch-and-bound algorithm. This note corrects the computational results in Averbakh and Pereira (2012).
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2472-5854 ISBN Medium
Area Expedition Conference
Notes WOS:000617722200001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1343
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Author Yuraszeck, F.; Mejia, G.; Pereira, J.; Vila, M.
Title (up) A Novel Constraint Programming Decomposition Approach for the Total Flow Time Fixed Group Shop Scheduling Problem Type
Year 2022 Publication Mathematics Abbreviated Journal Mathematics
Volume 10 Issue 3 Pages 329
Keywords scheduling; fixed group shop; group shop; constraint programming
Abstract This work addresses a particular case of the group shop scheduling problem (GSSP) which will be denoted as the fixed group shop scheduling problem (FGSSP). In a FGSSP, job operations are divided into stages and each stage has a set of machines associated to it which are not shared with the other stages. All jobs go through all the stages in a specific order, where the operations of the job at each stage need to be finished before the job advances to the following stage, but operations within a stage can be performed in any order. This setting is common in companies such as leaf spring manufacturers and other automotive companies. To solve the problem, we propose a novel heuristic procedure that combines a decomposition approach with a constraint programming (CP) solver and a restart mechanism both to avoid local optima and to diversify the search. The performance of our approach was tested on instances derived from other scheduling problems that the FGSSP subsumes, considering both the cases with and without anticipatory sequence-dependent setup times. The results of the proposed algorithm are compared with off-the-shelf CP and mixed integer linear programming (MILP) methods as well as with the lower bounds derived from the study of the problem. The experiments show that the proposed heuristic algorithm outperforms the other methods, specially on large-size instances with improvements of over 10% on average.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2227-7390 ISBN Medium
Area Expedition Conference
Notes WOS:000756126100001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1549
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Author Sandoval, G.; Alvarez-Miranda, E.; Pereira, J.; Rios-Mercado, R.Z.; Diaz, J.A.
Title (up) A novel districting design approach for on-time last-mile delivery: An application on an express postal company Type
Year 2022 Publication Omega-International Journal Of Management Science Abbreviated Journal Omega-Int. J. Manage. Sci.
Volume 113 Issue Pages 102687
Keywords Districting; Last-mile delivery; Postal delivery; Supply chain management; Heuristics
Abstract Last-mile logistics corresponds to the last leg of the supply chain, i.e., the delivery of goods to final cus-tomers, and they comprise the core activities of postal and courier companies. Because of their role in the supply chain, last-mile operations are critical for the perception of customers regarding the perfor-mance of the whole logistic process. In this sense, the sustained growth of e-commerce, which has been abruptly catalyzed by the irruption of the COVID-19 pandemic, has hanged the habits of customers and overtaxed the operational side of delivery companies, hindering their viability and forcing their adap-tation to the novel conditions. Many of these habits will remain after we overcome the sanitary crisis, which will permanently reshape the structure and emphasis of postal supply chains, demanding compa-nies to implement organizational and operational changes to adapt to these new challenges. In this work we address a last-mile logistic design problem faced by a courier and delivery company in Chile, although the same problem is likely to arise in the last-mile delivery operation of other postal companies, in particular in the operation of express delivery services. The operational structure of the company is based on the division of an urban area into smaller territories (districts) and the outsourcing of the delivery operation of each territory to a last-mile contractor. Because of the increasing volume of postal traffic and a decreasing performance of the service, in particular for the case of express deliveries, the company is forced to redesign its current territorial arrangement. Such redesign results in a novel optimization problem that resembles a classical districting problem with the additional quality of service requirements. This novel problem is first formulated as a mathematical programming model and then a specially tailored heuristic is designed for solving it. The proposed approach is tested on instances from the real-life case study, and the obtained results show significant improvements in terms of the percent-age of on-time deliveries achieved by the proposed solution when compared to the current districting design of the company. By performing a sensitivity analysis considering different levels of demand, we show that the proposed approach is effective in providing districting designs capable of enduring signifi-cant increases in the demand for express postal services.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0305-0483 ISBN Medium
Area Expedition Conference
Notes WOS:000809666900001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1605
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Author Pereira, J.; Alvarez-Miranda, E.
Title (up) An exact approach for the robust assembly line balancing problem Type
Year 2018 Publication Omega-International Journal Of Management Science Abbreviated Journal Omega-Int. J. Manage. Sci.
Volume 78 Issue Pages 85-98
Keywords Line balancing; Robust optimization; Lower bounds; Branch-and-bound
Abstract This work studies an assembly line balancing problem with uncertainty on the task times. In order to deal with the uncertainty, a robust formulation to handle changes in the operation times is put forward. In order to solve the problem, several lower bounds, dominance rules and an enumeration procedure are proposed. These methods are tested in a computational experiment using different instances derived from the literature and then compared to similar previous approaches. The results of the experiment show that the method is able to solve larger instances in shorter running times. Furthermore, the cost of protecting a solution against uncertainty is also investigated. The results highlight that protecting an assembly line against moderate levels of uncertainty can be achieved at the expense of small quantities of additional resources (stations). (C) 2017 Elsevier Ltd. All rights reserved.
Address [Pereira, Jordi] Univ Adolfo Ibanez, Fac Engn & Sci, Av Pedro Hurtado 750,Off A-215, Vina Del Mar, Chile, Email: jorge.pereira@uai.cl
Corporate Author Thesis
Publisher Pergamon-Elsevier Science Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0305-0483 ISBN Medium
Area Expedition Conference
Notes WOS:000433266700007 Approved
Call Number UAI @ eduardo.moreno @ Serial 872
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Author Opazo, D.; Moreno, S.; Alvarez-Miranda, E.; Pereira, J.
Title (up) Analysis of First-Year University Student Dropout through Machine Learning Models: A Comparison between Universities Type
Year 2021 Publication Mathematics Abbreviated Journal Mathematics
Volume 20 Issue 9 Pages 2599
Keywords machine learning; first-year student dropout; universities
Abstract Student dropout, defined as the abandonment of a high education program before obtaining the degree without reincorporation, is a problem that affects every higher education institution in the world. This study uses machine learning models over two Chilean universities to predict first-year engineering student dropout over enrolled students, and to analyze the variables that affect the probability of dropout. The results show that instead of combining the datasets into a single dataset, it is better to apply a model per university. Moreover, among the eight machine learning models tested over the datasets, gradient-boosting decision trees reports the best model. Further analyses of the interpretative models show that a higher score in almost any entrance university test decreases the probability of dropout, the most important variable being the mathematical test. One exception is the language test, where a higher score increases the probability of dropout.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2227-7390 ISBN Medium
Area Expedition Conference
Notes Approved
Call Number UAI @ alexi.delcanto @ Serial 1463
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Author Alvarez-Miranda, E.; Pereira, J.; Vila, M.
Title (up) Analysis of the simple assembly line balancing problem complexity Type
Year 2023 Publication Computers & Operations Research Abbreviated Journal Comput. Oper. Res.
Volume 159 Issue Pages 106323
Keywords Manufacturing; Assembly line balancing; Packing; Precedence constraints; Instance sets
Abstract The simple assembly line balancing problem (SALBP) involves the determination of the assignment of elementary assembly operations to the workstations of the assembly line for the manufacture of a final product, with the objective of maximising assembly efficiency. In addition to its practicality, the SALBP can be considered as an extension of the bin packing problem (BPP) to account for the precedence relations between items. These constraints introduce an ordering component to the problem, which increases the complexity of SALBP resolution. However, previous studies indicated that precedence constraints do not play an important role in the capacity of state-of-the-art procedures to solve benchmark instances to optimality. In this study, we analysed the influences of different features of an SALBP instance on the performance of state-of-the-art solution methods for the abovementioned problem. First, we provide an alternative proof of complexity for the SALBP that uses precedence constraints to demonstrate its non-deterministic polynomial time (NP)-complete status, followed by a new set of benchmark instances directed towards an empirical analysis of the different features of SALBP instances. The experimental results revealed that the packing features of the SALBP are a major source of the perceived difficulty for any instance; however, precedence constraints play a role in the performance of these solution procedures. Specifically, the number of precedence constraints plays an important role in the results obtained from state-of-the-art methods. In addition to the analysis, certain issues that were identified in the publicly available implementations of the state-of-the-art method for resolving this problem were addressed in this study.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0305-0548 ISBN Medium
Area Expedition Conference
Notes WOS:001033536100001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1849
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Author Alvarez-Miranda, E.; Chace, S.; Pereira, J.
Title (up) Assembly line balancing with parallel workstations Type
Year 2021 Publication International Journal Of Production Research Abbreviated Journal Int. J. Prod. Res.
Volume 59 Issue 21 Pages 6486-6506
Keywords Line balancing; parallel stations; dynamic programming; hybrid metaheuristic; matheuristic
Abstract The simple assembly line balancing problem (SALBP) considers work division among different workstations of a serially arranged assembly process to maximise its efficiency under workload (cumulative) and technological (precedence) constraints. In this work, we consider a variant of the SALBP which allows parallel workstations. To study the effect of parallel stations, we propose a new problem (the parallel station assembly line balancing problem or PSALBP) in which the objective is to minimise the number of parallel stations required to obtain the maximum theoretical efficiency of the assembly process. We study the complexity of the problem and identify a polynomially solvable case. This result is then used as a building block for the development of a heuristic solution procedure. Finally, we carry out a computational experiment to identify the characteristics of assembly lines that may benefit from station paralleling and to evaluate the performance of the proposed heuristic.
Address [alvarez-Miranda, Eduardo] Univ Talca, Fac Engn, Dept Ind Engn, Curico, Chile, Email: jorge.pereira@uai.cl
Corporate Author Thesis
Publisher Taylor & Francis Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-7543 ISBN Medium
Area Expedition Conference
Notes WOS:000569837900001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1243
Permanent link to this record
 

 
Author Alvarez-Miranda, E.; Pereira, J.
Title (up) Designing and constructing networks under uncertainty in the construction stage: Definition and exact algorithmic approach Type
Year 2017 Publication Computers & Operations Research Abbreviated Journal Comput. Oper. Res.
Volume 81 Issue Pages 178-191
Keywords Network design; Network construction; Two-stage robust optimization; Exact algorithms
Abstract The present work proposes a novel Network Optimization problem whose core is to combine both network design and network construction scheduling under uncertainty into a single two-stage robust optimization model. The first-stage decisions correspond to those of a classical network design problem, while the second-stage decisions correspond to those of a network construction scheduling problem (NCS) under uncertainty. The resulting problem, which we will refer to as the Two-Stage Robust Network Design and Construction Problem (2SRNDC), aims at providing a modeling framework in which the design decision not only depends on the design costs (e.g., distances) but also on the corresponding construction plan (e.g., time to provide service to costumers). We provide motivations, mixed integer programming formulations, and an exact algorithm for the 2SRNDC. Experimental results on a large set of instances show the effectiveness of the model in providing robust solutions, and the capability of the proposed algorithm to provide good solutions in reasonable running times. (C) 2017 Elsevier Ltd. All rights reserved.
Address [Alvarez-Miranda, Eduardo] Univ Talca, Dept Ind Engn, Curico, Chile, Email: ealvarez@utalca.cl
Corporate Author Thesis
Publisher Pergamon-Elsevier Science Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0305-0548 ISBN Medium
Area Expedition Conference
Notes WOS:000394079400015 Approved
Call Number UAI @ eduardo.moreno @ Serial 706
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Author Melo, I.C.; Alves, P.N.; Queiroz, G.A.; Yushimito, W.; Pereira, J.
Title (up) Do We Consider Sustainability When We Measure Small and Medium Enterprises' (SMEs') Performance Passing through Digital Transformation? Type
Year 2023 Publication Sustainability Abbreviated Journal Sustainability
Volume 15 Issue 6 Pages 4917
Keywords digitalization; small- and medium-sized enterprises (SMEs); Industry 4; 0; topic modeling; latent dirichlet allocation (LDA); triple bottom line of sustainability
Abstract Small-medium enterprises (SMEs) represent 90% of business globally. Digital Transformation (DT) affects SMEs differently from larger companies because although SMEs have more flexibility and agility for adapting to new circumstances, they also have more limited resources and specialization capabilities. Thus, it is fundamental to measure SMEs' performance considering different perspectives. Here, we describe and analyze the state-of-the-art of DT in SMEs, focusing on performance measurement. We center on whether the tools used by SMEs encompass the triple bottom line of sustainability (i.e., environmental, social, and economic aspects). To do so, in December 2021, we performed a comprehensive systematic literature review (SLR) on the Web of Science and Scopus. In addition, we also explored a novel approach for SLR: topic modeling with a machine learning technique (Latent Dirichlet Allocation). The differences and interchangeability of both methods are discussed. The findings show that sustainability is treated as a separate topic in the literature. The social and environmental aspects are the most neglected. This paper contributes to sustainable development goals (SDGs) 1, 5, 8, 9, 10, and 12. A conceptual framework and future research directions are proposed. Thus, this paper is also valuable for policymakers and SMEs switching their production paradigm toward sustainability and DT.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2071-1050 ISBN Medium
Area Expedition Conference
Notes WOS:000958416000001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1770
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Author Pereira, J.; Ritt, M.
Title (up) Exact and heuristic methods for a workload allocation problem with chain precedence constraints Type
Year 2023 Publication European Journal Of Operational Research Abbreviated Journal Eur. J. Oper. Res.
Volume 309 Issue 1 Pages 387-398
Keywords Manufacturing; Assembly line balancing; Worker allocation; Dynamic programming; Branch and bound
Abstract Industrial manufacturing is often organized in assembly lines where a product is assembled on a se-quence of stations, each of which executes some of the assembly tasks. A line is balanced if the maximum total execution time of any station is minimal. Commonly, the task execution order is constrained by precedences, and task execution times are independent of the station performing the task. Here, we con -sider a recent variation, called the “(Calzedonia) Workload Allocation Problem” (WAP), where the prece-dences form a chain, and the execution time of a task depends on the worker executing it. This problem was recently proposed by Battarra et al. (2020) and it is a special case of the Assembly Line Worker As-signment and Balancing Problem Miralles et al. (2007) where precedence relations are arbitrary. In this paper we consider the computational complexity of the problem and prove its NP-hardness. To solve the problem, we provide different lower bounds and exact and heuristic procedures. The performance of the proposed methods is tested on previously proposed instances and on new, larger instances with the same characteristics. The results show that the proposed methods can solve instances with up to about 40 0 0 tasks and 29 workers, doubling the size of the instances that previously could be solved to optimality.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0377-2217 ISBN Medium
Area Expedition Conference
Notes WOS:000970067900001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1794
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Author Ritt, M.; Pereira, J.
Title (up) Heuristic and exact algorithms for minimum-weight non-spanning arborescences Type
Year 2020 Publication European Journal Of Operational Research Abbreviated Journal Eur. J. Oper. Res.
Volume 287 Issue 1 Pages 61-75
Keywords Minimum-weight non-spanning arborescence; Heuristic; Iterated Local Search; Branch-and-cut
Abstract We address the problem of finding an arborescence of minimum total edge weight rooted at a given vertex in a directed, edge-weighted graph. If the arborescence must span all vertices the problem is solvable in polynomial time, but the non-spanning version is NP-hard. We propose reduction rules which determine vertices that are required or can be excluded from optimal solutions, a modification of Edmonds algorithm to construct arborescences that span a given set of selected vertices, and embed this procedure into an iterated local search for good vertex selections. Moreover, we propose a cutset-based integer linear programming formulation, provide different linear relaxations to reduce the number of variables in the model and solve the reduced model using a branch-and-cut approach. We give extensive computational results showing that both the heuristic and the exact methods are effective and obtain better solutions on instances from the literature than existing approaches, often in much less time. (C) 2020 Elsevier B.V. All rights reserved.
Address [Ritt, Marcus] Univ Fed Rio Grande do Sul, Inst Informat, Av Bento Goncalves 9500, Porto Alegre, RS, Brazil, Email: marcus.ritt@inf.ufrgs.br;
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0377-2217 ISBN Medium
Area Expedition Conference
Notes WOS:000541072800005 Approved
Call Number UAI @ eduardo.moreno @ Serial 1187
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Author Averbakh, I.; Pereira, J.
Title (up) Lateness Minimization in Pairwise Connectivity Restoration Problems Type
Year 2018 Publication Informs Journal On Computing Abbreviated Journal INFORMS J. Comput.
Volume 30 Issue 3 Pages 522-538
Keywords combinatorial optimization; networks: scheduling; programming: branch and bound; network restoration; network construction; integrated network design and scheduling
Abstract A network is given whose edges need to be constructed (or restored after a disaster). The lengths of edges represent the required construction/restoration times given available resources, and one unit of length of the network can be constructed per unit of time. All points of the network are accessible for construction at any time. For each pair of vertices, a due date is given. It is required to find a construction schedule that minimizes the maximum lateness of all pairs of vertices, where the lateness of a pair is the difference between the time when the pair becomes connected by an already constructed path and the pair's due date. We introduce the problem and analyze its structural properties, present a mixed-integer linear programming formulation, develop a number of lower bounds that are integrated in a branch-and-bound algorithm, and discuss results of computational experiments both for instances based on randomly generated networks and for instances based on 2010 Chilean earthquake data.
Address [Averbakh, Igor] Univ Toronto Scarborough, Dept Management, Toronto, ON M1C 1A4, Canada, Email: averbakh@utsc.uturonto.ca;
Corporate Author Thesis
Publisher Informs Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1091-9856 ISBN Medium
Area Expedition Conference
Notes WOS:000449096000008 Approved
Call Number UAI @ eduardo.moreno @ Serial 924
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Author Osorio-Valenzuela, L.; Pereira, J.; Quezada, F.; Vasquez, O.C.
Title (up) Minimizing the number of machines with limited workload capacity for scheduling jobs with interval constraints Type
Year 2019 Publication Applied Mathematical Modelling Abbreviated Journal Appl. Math. Model.
Volume 74 Issue Pages 512-527
Keywords Scheduling; Parallel machines; Interval and workload constraints; Branch-and-price
Abstract In this paper, we consider a parallel machine scheduling problem in which machines have a limited workload capacity and jobs have deadlines and release dates. The problem is motivated by the operation of energy storage management systems for microgrids under emergency conditions and generalizes some problems that have already been studied in the literature for their theoretical value. In this work, we propose heuristic and exact algorithms to solve the problem. The heuristics are adaptations of classical bin packing heuristics in which additional conditions on the feasibility of a solution are imposed, whereas the exact method is a branch-and-price approach. The results show that the branch-andprice approach is able to optimally solve random instances with up to 250 jobs within a time limit of one hour, while the heuristic procedures provide near optimal solution within reduced running times. Finally, we also provide additional complexity results for a special case of the problem. (C) 2019 Elsevier Inc. All rights reserved.
Address [Osorio-Valenzuela, Luis] Univ Santiago Chile, Elect Engn Dept, Santiago, Chile, Email: luis.osoriov@usach.cl;
Corporate Author Thesis
Publisher Elsevier Science Inc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0307-904x ISBN Medium
Area Expedition Conference
Notes WOS:000474317800031 Approved
Call Number UAI @ eduardo.moreno @ Serial 1013
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