Records |
Author |
Alvarez-Miranda, E.; Campos-Valdes, C.; Quiroga, M.M.; Moreno-Faguett, M.; Pereira, J. |
Title |
A Multi-Criteria Pen for Drawing Fair Districts: When Democratic and Demographic Fairness Matter |
Type |
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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; |
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Mdpi |
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2227-7390 |
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WOS:000580771600001 |
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UAI @ alexi.delcanto @ |
Serial |
1246 |
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Author |
Campos-Valdes, C.; Alvarez-Miranda, E.; Quiroga, MM; Pereira, J.; Duran, FL. |
Title |
The Impact of Candidates' Profile and Campaign Decisions in Electoral Results: A Data Analytics Approach |
Type |
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Year |
2021 |
Publication |
Mathematics |
Abbreviated Journal |
Mathematics |
Volume  |
9 |
Issue |
8 |
Pages |
902 |
Keywords |
Chilean parliamentary election; candidate profiles; campaign efforts; territorial deployment |
Abstract |
In recent years, a wide range of techniques has been developed to predict electoral results and to measure the influence of different factors in these results. In this paper, we analyze the influence of the political profile of candidates (characterized by personal and political features) and their campaign effort (characterized by electoral expenditure and by territorial deployment strategies retrieved from social networks activity) on the electoral results. This analysis is carried out by using three of the most frequent data analyitcs algorithms in the literature. For our analysis, we consider the 2017 Parliamentary elections in Chile, which are the first elections after a major reform of the electoral system, that encompassed a transition from a binomial to a proportional system, a modification of the districts' structure, an increase in the number of seats, and the requirement of gender parity in the lists of the different coalitions. The obtained results reveal that, regardless of the political coalition, the electoral experience of candidates, in particular in the same seat they are running for (even when the corresponding district is modified), is by large the most influential factor to explain the electoral results. However, the attained results show that the influence of other features, such as campaign expenditures, depends on the political coalition. Additionally, by means of a simulation procedure, we show how different levels of territorial deployment efforts might impact on the results of candidates. This procedure could be used by parties and coalitions when planning their campaign strategies. |
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2227-7390 |
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WOS:000644524000001 |
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UAI @ alexi.delcanto @ |
Serial |
1377 |
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Author |
Alvarez-Miranda, E.; Pereira, J.; Torrez-Meruvia H.; Vila, M. |
Title |
A Hybrid Genetic Algorithm for the Simple Assembly Line Balancing Problem with a Fixed Number of Workstations |
Type |
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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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2227-7390 |
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WOS:000694360700001 |
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UAI @ alexi.delcanto @ |
Serial |
1466 |
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Author |
Melo, I.C.; Queiroz, G.A.; Junior, P.N.A.; de Sousa, T.B.; Yushimito, W.F.; Pereira, J. |
Title |
Sustainable digital transformation in small and medium enterprises (SMEs): A review on performance |
Type |
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Year |
2023 |
Publication |
Heliyon |
Abbreviated Journal |
Heliyon |
Volume  |
9 |
Issue |
3 |
Pages |
e13908 |
Keywords |
Digitalization; Small and medium-sized enterprises (SMEs); Industry 40Triple bottom line (TBL) of sustainability; Sustainable development goals (SDG) |
Abstract |
Small and medium enterprises (SMEs) are responsible for 90% of all business and 50% of employment globally, mostly female jobs. Therefore, measuring SMEs' performance under the digital transformation (DT) through methods that encompass sustainability represents an essential tool for reducing poverty and gender inequality (United Nations Sustainable Development Goals). We aimed to describe and analyze the state-of-art performance evaluations of digital transformation in SMEs, mainly focusing on performance measurement. Also, we aimed to determine whether the tools encompass the three pillars of sustainability (environmental, social, and economic). Through a systematic literature review (SLR), a search on Web of Science (WoS) and Scopus resulted in the acceptance of 74 peer-reviewed papers published until December 2021. Additionally, a bibliometrics investigation was executed. Although there was no time restriction, the oldest paper was published in 2016, indicating that DT is a new research topic with increasing interest. Italy, China, and Finland are the countries that have the most published on the theme. Based on the results, a conceptual framework is proposed. Also, two future research directions are presented and discussed, one for theoretical and another for practical research. Among the theoretical development, it is essential to work on a widely accepted SME definition. Among the practical research, nine directions are identified-e.g., applying big data, sectorial and regional prioritization, cross-temporal investigations etc. Researchers can follow the presented avenues and roads to guide their researchers toward the most relevant topics with the most urgent necessity of investigation. |
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2405-8440 |
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WOS:000968115200001 |
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UAI @ alexi.delcanto @ |
Serial |
1782 |
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Author |
Alvarez-Miranda, E.; Pereira, J. |
Title |
A Districting Application with a Quality of Service Objective |
Type |
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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. |
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2227-7390 |
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Notes |
WOS:000751158600001 |
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UAI @ alexi.delcanto @ |
Serial |
1529 |
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Author |
Yuraszeck, F.; Mejia, G.; Pereira, J.; Vila, M. |
Title |
A Novel Constraint Programming Decomposition Approach for the Total Flow Time Fixed Group Shop Scheduling Problem |
Type |
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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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2227-7390 |
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Notes |
WOS:000756126100001 |
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UAI @ alexi.delcanto @ |
Serial |
1549 |
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Author |
Melo, I.C.; Alves, P.N.; Queiroz, G.A.; Yushimito, W.; Pereira, J. |
Title |
Do We Consider Sustainability When We Measure Small and Medium Enterprises' (SMEs') Performance Passing through Digital Transformation? |
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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. |
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2071-1050 |
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WOS:000958416000001 |
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UAI @ alexi.delcanto @ |
Serial |
1770 |
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Author |
Opazo, D.; Moreno, S.; Alvarez-Miranda, E.; Pereira, J. |
Title |
Analysis of First-Year University Student Dropout through Machine Learning Models: A Comparison between Universities |
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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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2227-7390 |
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UAI @ alexi.delcanto @ |
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1463 |
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Author |
Averbakh, I.; Pereira, J. |
Title |
Lateness Minimization in Pairwise Connectivity Restoration Problems |
Type |
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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; |
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Informs |
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English |
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1091-9856 |
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WOS:000449096000008 |
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UAI @ eduardo.moreno @ |
Serial |
924 |
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Author |
Cohen, Y.M.; Keskinocak, P.; Pereira, J. |
Title |
A note on the flowtime network restoration problem |
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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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2472-5854 |
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WOS:000617722200001 |
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UAI @ alexi.delcanto @ |
Serial |
1343 |
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Author |
Pereira, J.; Vila, M. |
Title |
A new model for supply chain network design with integrated assembly line balancing decisions |
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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 |
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Taylor & Francis Ltd |
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English |
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0020-7543 |
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WOS:000373632300009 |
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UAI @ eduardo.moreno @ |
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608 |
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Author |
Mejia, G.; Pereira, J. |
Title |
Multiobjective scheduling algorithm for flexible manufacturing systems with Petri nets |
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Year |
2020 |
Publication |
Journal Of Manufacturing Systems |
Abbreviated Journal |
J. Manuf. Syst. |
Volume  |
54 |
Issue |
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Pages |
272-284 |
Keywords |
Machine scheduling; Multi-objective optimization; Petri nets |
Abstract |
In this work, we focus on general multi-objective scheduling problems that can be modeled using a Petri net framework. Due to their generality, Petri nets are a useful abstraction that captures multiple characteristics of real-life processes. To provide a general solution procedure for the abstraction, we propose three alternative approaches using an indirect scheme to represent the solution: (1) a genetic algorithm that combines two objectives through a weighted fitness function, (2) a non dominated sorting genetic algorithm (NSGA-II) that explicitly addresses the multi-objective nature of the problem and (3) a multi-objective local search approach that simultaneously explores multiple candidate solutions. These algorithms are tested in an extensive computational experiment showing the applicability of this general framework to obtain quality solutions. |
Address |
[Mejia, Gonzalo] Univ La Sabana, Fac Engn, Campus Puente del Comun, Chia, Colombia, Email: gonzalo.mejia@unisabana.edu.co; |
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Elsevier Sci Ltd |
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English |
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0278-6125 |
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WOS:000521511500021 |
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UAI @ eduardo.moreno @ |
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1154 |
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Author |
Pereira, J. |
Title |
Modelling and solving a cost-oriented resource-constrained multi-model assembly line balancing problem |
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2018 |
Publication |
International Journal Of Production Research |
Abbreviated Journal |
Int. J. Prod. Res. |
Volume  |
56 |
Issue |
11 |
Pages |
3994-4016 |
Keywords |
assembly line balancing; combinatorial optimisation; lower bound; heuristics; estimation of distribution algorithm |
Abstract |
A line balancing problem considers the assignment of operations to workstations in an assembly line. While assembly lines are usually associated to mass production of standardised goods, their advantages have led to their widespread use whenever a product-oriented production system is applicable and the benefits of the labour division and specialisation are significant, even when some of its characteristics may deviate from classical assembly lines. In this work, we study a line balancing problem found in the textile industry in which the line must be balanced for multiple types of goods taking into account resource requirements. In order to solve the problem, a hybrid method that combines classical methods for line balancing with an Estimation of Distribution Algorithm is proposed. Computational experiments show that the new procedure improves upon the state of the art when compared using a benchmark set derived from the literature, as well as when compared using data from the manufacturer that originated this research work. |
Address |
[Pereira, Jordi] Univ Adolfo Ibanez, Fac Engn & Sci, Vina Del Mar, Chile, Email: jorge.pereira@uai.cl |
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Taylor & Francis Ltd |
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0020-7543 |
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WOS:000438403800013 |
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UAI @ eduardo.moreno @ |
Serial |
889 |
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Author |
Alvarez-Miranda, E.; Chace, S.; Pereira, J. |
Title |
Assembly line balancing with parallel workstations |
Type |
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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 |
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Publisher |
Taylor & Francis Ltd |
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Language |
English |
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Edition |
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ISSN |
0020-7543 |
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Notes |
WOS:000569837900001 |
Approved |
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Call Number |
UAI @ alexi.delcanto @ |
Serial |
1243 |
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Author |
Alvarez-Miranda, E.; Pereira, J.; Vargas, C.; Vila, M. |
Title |
Variable-depth local search heuristic for assembly line balancing problems |
Type |
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Year |
2022 |
Publication |
International Journal Of Production Research |
Abbreviated Journal |
Int. J. Prod. Res. |
Volume  |
61 |
Issue |
9 |
Pages |
3103-3121 |
Keywords |
Assembly lines; Manufacturing; simple assembly line balancing; local search; variable-depth local search |
Abstract |
Assembly lines are production flow systems wherein activities are organised around a line consisting of various workstations through which the product flows. At each station, the product is assembled through a subset of operations. The assembly line balancing problem (ALBP) consists of allocating operations between stations to maximise the system efficiency. In this study, a variable-depth local search algorithm is proposed for solving simple assembly line balancing problems (SALBPs), which are the most widely studied versions of the ALBP. Although the state-of-the-art techniques for solving the SALBP consist of exact enumeration-based methods or heuristics, this paper proposes a local search-based heuristic using variable-length sequences that allow the solution space to be efficiently explored. The proposed algorithm improves the best solution known for multiple instances reported in the literature, indicating that its efficiency is comparable to those of the state-of-the-art method for solving the SALBP. Moreover, the characteristics of the instances for which the proposed procedure provides a better solution than previously reported construction procedures are investigated. |
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ISSN |
0020-7543 |
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Notes |
WOS:000800928700001 |
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Call Number |
UAI @ alexi.delcanto @ |
Serial |
1578 |
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Author |
Pereira, J. |
Title |
The robust (minmax regret) single machine scheduling with interval processing times and total weighted completion time objective |
Type |
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Year |
2016 |
Publication |
Computers & Operations Research |
Abbreviated Journal |
Comput. Oper. Res. |
Volume  |
66 |
Issue |
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Pages |
141-152 |
Keywords |
Scheduling; Single machine; Uncertainty; Robust optimization; Branch-and-bound |
Abstract |
Single machine scheduling is a classical optimization problem that depicts multiple real life systems in which a single resource (the machine) represents the whole system or the bottleneck operation of the system. In this paper we consider the problem under a weighted completion time performance metric in which the processing time of the tasks to perform (the jobs) are uncertain, but can only take values from closed intervals. The objective is then to find a solution that minimizes the maximum absolute regret for any possible realization of the processing times. We present an exact branch-and-bound method to solve the problem, and conduct a computational experiment to ascertain the possibilities and limitations of the proposed method. The results show that the algorithm is able to optimally solve instances of moderate size (25-40 jobs depending on the characteristics of the instance). (c) 2015 Elsevier Ltd. All rights reserved. |
Address |
[Pereira, Jordi] Univ Adolfo Ibanez, Fac Sci & Engn, Vina Del Mar, Chile, Email: jorge.pereira@uai.cl |
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Publisher |
Pergamon-Elsevier Science Ltd |
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English |
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ISSN |
0305-0548 |
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Notes |
WOS:000366779900013 |
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Call Number |
UAI @ eduardo.moreno @ |
Serial |
558 |
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Author |
Pereira, J.; Ritt, M |
Title |
A note on “Algorithms for the Calzedonia workload allocation problem” |
Type |
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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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ISSN |
0160-5682 |
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Notes |
WOS:000627308200001 |
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Call Number |
UAI @ alexi.delcanto @ |
Serial |
1351 |
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Author |
Osorio-Valenzuela, L.; Pereira, J.; Quezada, F.; Vasquez, O.C. |
Title |
Minimizing the number of machines with limited workload capacity for scheduling jobs with interval constraints |
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Year |
2019 |
Publication |
Applied Mathematical Modelling |
Abbreviated Journal |
Appl. Math. Model. |
Volume  |
74 |
Issue |
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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; |
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Publisher |
Elsevier Science Inc |
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English |
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ISSN |
0307-904x |
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Notes |
WOS:000474317800031 |
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Call Number |
UAI @ eduardo.moreno @ |
Serial |
1013 |
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Author |
Pereira, J.; Alvarez-Miranda, E. |
Title |
An exact approach for the robust assembly line balancing problem |
Type |
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Year |
2018 |
Publication |
Omega-International Journal Of Management Science |
Abbreviated Journal |
Omega-Int. J. Manage. Sci. |
Volume  |
78 |
Issue |
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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 |
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Pergamon-Elsevier Science Ltd |
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English |
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ISSN |
0305-0483 |
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Notes |
WOS:000433266700007 |
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Call Number |
UAI @ eduardo.moreno @ |
Serial |
872 |
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Author |
Alvarez-Miranda, E.; Pereira, J. |
Title |
Designing and constructing networks under uncertainty in the construction stage: Definition and exact algorithmic approach |
Type |
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Year |
2017 |
Publication |
Computers & Operations Research |
Abbreviated Journal |
Comput. Oper. Res. |
Volume  |
81 |
Issue |
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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 |
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Pergamon-Elsevier Science Ltd |
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English |
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ISSN |
0305-0548 |
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Notes |
WOS:000394079400015 |
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Call Number |
UAI @ eduardo.moreno @ |
Serial |
706 |
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