Denis Borenstein

• Phd, Management Science
• Professor (Full) at Federal University of Rio Grande do Sul

This paper explores the complex logistics of ship routing and scheduling for fertilizer companies in Brazil, considering the challenges posed by a dynamic international trade landscape affected by factors such as the COVID-19 pandemic and geopolitical conflicts. It expands previous research by incorporating cargo allocation to the heterogeneous fle...

Private banking is one of the most profitable services offered by financial institutions in Brazil. In this service, a client should consider the suitability of a range of banking product, during his or her life based on dynamic objectives. It is a very complex service that involves regulation from governmental agencies, financial institutions’ int...

This work considers the strategic Supply Chain Network Design (SCND) problem, which is to define the number and location of facilities, and the flow of products among them to fulfilling a long-term deterministic demand. A two-phase heuristic approach was specially developed to solve large scale problems in reasonable time, extending a previous algo...

This paper provides a customized optimization approach for the long-term audit staff scheduling problem of aviation approved training organizations (ATO) in Brazil. We formulate the problem as a set covering problem by considering both auditors’ assignments and ATO’s arrangements to minimize the total cost of staff traveling. However, the developed...

Irregular demand in retail is characterized by stock keeping units (SKUs) that present high intermittency, and simultaneously, high erraticness (classified as lumpy demand) or low erraticness (classified as intermittent demand), following the classification of Syntetos, Boylan, and Croston (2005). These SKUs are basically defined by periods of zero...

This paper presents an embracing quantitative inbreeding analyses in the Brazilian higher education system (HES). Several studies were conducted about academic inbreeding in several countries with contradictory results on its effect in research productivity, indicating how controversial this issue is. This is the first comprehensive research based...

This paper addresses the multi‐objective maritime cargo routing and scheduling problem, in which the delivery of bulk products from pickup to delivery ports is served by a heterogeneous fleet of vessels. A mixed integer linear programming (MILP) model is formulated to simultaneously minimize total operation costs, the scheduling makespan, and delay...

Forecasting is one of the fundamental inputs to support planning decisions in retail chains. Frequently, forecasting systems in retail are based on Gaussian models, which may be highly unrealistic when considering daily retail data. In addition, the majority of these systems rely on point forecasts, limiting their practical use in retailing decisio...

This study was motivated by the high costs incurred by an energy company for repairable spare parts for faulty mission-critical items, particularly with those that operate until failure. The objective of this paper is to develop and apply a method for repairable spare part inventory management of run-to-failure equipment. To achieve a robust method...

This study presents a mixed-integer linear programming (MILP) model and a solution method for a maritime cargo routing and shipping problem faced by a chemical company in Brazil. This problem is associated with the operational planning of multiple raw materials, collected from European ports and delivered to Brazilian ones to supply mixing producti...

Lotka’s law is a power law for the frequency of scholarly publications. We show that Lotka’s law cannot be dismissed after considering a massive sample of the number of publications of Brazilian researchers in journals listed on the SCImago Journal Rank and the Journal Citation Reports. For the SCImago Journal Rank, we found a power law with the Pa...

This paper presents an optimization approach for the bus scheduling problem in transit systems, considering the loss in ridership. This research work is motivated by the considerable loss in the demand for bus transportation in Brazil in the last few decades. The main objective of the optimization approach is to allow transit operators to adjust th...

ABSTRACT In the context of a heterogeneous fleet, the single-depot Vehicle Scheduling Problem is known as the Vehicle Type Scheduling Problem (VTSP). In this paper, we extend a VTSP model proposed in the literature to enable timetabling flexibility. Two strategies were developed to promote flexibility: aggregated trips and time windows. The former...

In this article, our goal is to introduce a statistical process control charts approach (SPC) to monitor the rebalancing process of index tracking (IT) portfolios. SPC methods derive from statistics and engineering as tools to control production process. We use exponentially weighted moving average (EWMA) control charts to monitor IT portfolios bas...

This paper introduces an optimization approach for solving the sawing stock problem in a sawmill in Brazil using the cant sawing pattern, in which lateral and central pieces are cut from the log surface. As this problem has been proved NP-hard and involves some nonlinearities due to the circular geometry of this pattern, we developed a solution met...

p>Uno de los pilares importantes del Sistema Financiero Ecuatoriano es el constituido por las Cooperativas de Ahorro y Crédito, debido a su amplio crecimiento obtenido en los últimos años y la gran cantidad de clientes que han logrado atraer. El objetivo principal de este estudio, es realizar un análisis sobre la Eficiencia Técnica de 18 Cooperativ...

Using a database of potential, possible, or probable predatory scholarly open-access journals, the objective of this research is to study the penetration of predatory publications in the Brazilian academic system and the profile of authors in a cross-section empirical study. Based on a massive amount of publications from Brazilian researchers of al...

The multiple-depot vehicle type rescheduling problem (MDVTRSP) is a dynamic extension of the classic multiple-depot vehicle scheduling problem (MDVSP), where a heterogeneous fleet is considered. The MDVTRSP consists of finding a new schedule given that a severe disruption occurred in previously scheduled trips very quickly, simultaneously minimizin...

In this paper, we propose an integer linear programming (ILP) aiming at optimizing timetabling generation and the Vehicle Type Scheduling Problem (VTSP), based on a time-space network (TSN). The model was defined as Vehicle Type Scheduling Problem with Sequential Changes of timetable (VTSP- SCT). Additionally, we developed a new methodology to inse...

Neste artigo, propõe-se um novo modelo de Programação Linear Inteira, baseado em uma rede tempo-espaço, que integra os problemas de geração da tabela de horários e o escalonamento de veículos com frota heterogênea. Um diferencial dessa abordagem consiste na consideração da demanda para a redefinição da tabela de horários e para o escalonamento dos...

In this paper, we discuss the index tracking strategy using mathematical programming. First, we use a non-linear programming formulation for the index tracking problem, considering a limited number of assets. Since the problem is difficult to be solved in reasonable time by commercial mathematical packages, we apply a hybrid solution approach, comb...

En función del Programa Prometeo, del cual formó parte el Grupo de Investigación Empresarial (GIE) y la Carrera de Administración de Empresas de la Facultad de Ciencias Económicas y Administrativas de la Universidad de Cuenca, conjuntamente con la Dirección de Investigación de la Universidad de Cuenca (DIUC), se llevó a cabo el proyecto de Investig...

El gobierno ecuatoriano se ha propuesto introducir de forma masiva en el mercado nacional, el uso de las cocinas de inducción, ello en reemplazo de la cocina GLP (Gas Licuado de Petróleo). Sin embargo en la elección de la cocina de inducción o GLP, por parte del ciudadano, además de los factores económicos intervienen también criterios o factores q...

Decision-making processes in private banking must comply with standards for risk management and transparency enforced by banking regulations. Therefore, investors must be supported throughout a risk-informed decision process. This paper contributes to the literature by presenting a hybrid integrated framework that considers personal features of the...

In this paper, we compare risk measures regarding performance of optimal portfolio strategies. We consider eleven risk measures from different classes. In particular, we propose a formulation that generates from any loss measure, a deviation based on the dispersion of results worse than it, which leads to very interesting risk measures. We consider...

Student selection is a complex decision-making process, in which several criteria need to be considered simultaneously. In this paper, we address this problem for a Brazilian university that has created an interdisciplinary degree in which several intermediate selection processes are required during the course, defining the final title degree. The...

We propose a simple heuristic method for the strategic Supply Chain Network Design (SCND) problem of a Brazilian tire company with four layers, multi-product in a single-period. Although several solution methods have been developed to solve this problem, mainly based on heuristic techniques, they have serious limitations in the number of warehouses...

This paper presents two different mathematical formulations for the Supply Chain Network Design of a company responsible for producing and distributing multi-commodity products. Investments in a new manufacturing plant required the readjustment of the company’s logistics project, with a necessary re-structuring of the raw materials and finished pro...

We assemble a massive sample of 180,000 CVs of Brazilian academic researchers of all disciplines from the Lattes platform. From the CVs we gather information on key variables related to the researchers and their publications. We find males are more productive in terms of quantity of publications, but the effect of gender in terms of research impact...

Scientific production has been the focus of many discussions, particularly regarding the issue of scientific productivity. This study analyzes the profile and publications of academics (PhDs) working in the field of management in Brazil and their respective scientific publications, in order to identify the factors that explain this particular aspec...

Using sectorial indices of the Brazilian market, we compare the portfolio optimization approach known as risk parity with minimum variance and equally weighted approaches. We apply various estimators for the covariance matrix to each portfolio strategy, since portfolio variance is considered as risk measure. Empirical results demonstrate that the r...

This paper describes an integrated decision analysis method to support the managing board to define a restructuring plan for a small oil refinery in south Brazil. The refinery is facing an extreme crisis situation due to the obsolescence of its production plant. The decision approach proposed in this paper consists of four phases. Initially, potent...

In this paper, we propose a hybrid fuzzy decision making approach, combining elements of fuzzy-ELECTRE and Fuzzy-TOPSIS, towards a new ranking procedure. The main objective of FETOPSIS is to offer rankings with good alternative discriminatory power to decision makers (DMs). This research work was motivated by a real case study in which multiple att...

This paper discusses the implementation and evaluation of a heuristic based on Tabu Search to optimize a supply chain network. To this end, a single-source model proposed by Farias & Borenstein (2012) was implemented. The problem was solved by adapting the Lee & Kwon method (2010), exchanging distribution centers (DCs) and arcs to find the lowest c...

Fuzzy-TOPSIS is one of the most widely applied methods for solving multi-attribute decision making problems. However, an analysis of academic and real-life applications of this method has pointed out that the final alternative scores are very close, with little dispersion among them, making it difficult for the decision makers' to choice/ranking th...

The multiple-depot vehicle-type scheduling problem (MDVTSP) is an extension of the classic multiple-depot vehicle scheduling problem (MDVSP), where heterogeneous fleet is considered. Although several mathematical formulations and solution methods have been developed for the MDVSP, the MDVTSP is still relatively unexplored. Large instances of the MD...

In this paper, a fast heuristic approach is proposed for solving the multiple depot vehicle scheduling problem (MDVSP), a well-known NP-hard problem. The heuristic is based on a two stage procedure. The first one applies two state space reduction procedures towards reducing the problem complexity. One procedure is based on the solutions of the sing...

This paper presents a comprehensive review on methods for real-time schedule recovery in transportation services. The survey concentrates on published research on recovery of planned schedules in the occurrence of one or several severe disruptions such as vehicle breakdowns, accidents, and delays. Only vehicle assignment and rescheduling are review...

Currently the logistical problems are relying quite significantly on Operational Research in order to achieve greater efficiency in their operations. Among the problems related to the vehicles scheduling in a logistics system, the Multiple Depot Vehicle Scheduling Problem (MDVSP) has been addressed in several studies. The MDVSP presupposes the exis...

Resumo Este trabalho tem por objetivo apresentar e discutir características dos modelos que tratam a Mobilidade Urbana e o Transporte Público em uma perspectiva mundial. A pesquisa bibliográfica foi realizada em importantes periódicos internacionais priorizando a aplicação da Pesquisa Operacional nos campos operacional, tático e estratégico para so...

Index tracking is a passive investment strategy, which aims at generating portfolios to reproduce a specific market index’s performance. This article proposes a model for a index tracking problem with control on the number of assets in the portfolio, which corresponds to a restriction in transaction costs. The model is applied to Ibovespa (sample:...

Este artigo teórico objetiva apresentar e discutir características de modelos matemáticos de otimização do projeto da cadeia de suprimentos global, a fim de sugerir perspectivas de pesquisas futuras. A pesquisa bibliográfica foi realizada nos mais importantes periódicos internacionais de pesquisa operacional, compreendendo, predominantemente, artig...

Resumo Index tracking e uma estratégia de investimento passiva, com objetivo de formar portfólios para reprodução do desempenho de um ındice do mercado. Esse ar-tigo apresenta uma proposta de modelagem de otimização de index tracking com controle do número de ativos na carteira, correspondentè a restriç ao de custos de transaç ao. O modeló e aplica...

Higher education in Brazil has experienced a rapid expansion since the 1990s as a consequence of the government’s pliability in launching new programs and educational institutions. This expansion was mainly driven by the private sector. Despite this expansion, Brazil has not yet achieved the enrollment goal expected in the National Education Plan l...

RESUMO Nos últimos anos o Brasil tem experimentado uma me-lhora de índices socioeconômicos e, simultaneamente, um problemático aumento da criminalidade urbana, seja contra a pessoa ou patrimônio, em especial com relação aos crimes de oportunidade. A aparente contradição desafia a comumente alegada correlação entre distribui-ção de riqueza e vários...

Os modelos de média-variância de otimização de carteira apresentam questionamentos em relação ao seu efetivo desempenho devido ao chamado erro de estimação. Em conseqüência, a otimização estocástica vêm aumentando sua importância devido à possibilidade da inclusão da incerteza na estimativa dos parâmetros. Neste estudo foi avaliado o desempenho do...

Porto Alegre / RS – Brasil Resumo Neste artigo são desenvolvidas duas modelagens matemáticas para o Projeto de Rede da Cadeia de Suprimentos de uma indústria responsável pela produção e distribuição multi-commodity. O investimento em uma nova fábrica exigiu a readequação do projeto logístico da empresa, implicando na readequação dos fluxos de matér...

The analysis and implementation of mass customization (MC) systems has received growing consideration by researchers and practitioners since the late 1980s. In this paper we update the literature review on MC presented in a previous paper (Da Silveira, G., Borenstein, D., Fogliatto, F.S., 2001. Mass customization: literature review and research dir...

The financial system, which has been investigated by various researchers, is a rather complicated environment. Most research has only been concerned with quantitative factors (technical indexes), though qualitative factors (e.g., political situation, social conditions, international events, government policies, among others) play a critical role in...

The aim of the present paper is to characterize and analyze the emergence of the biodiesel industry in Brazil, and provide an assessment of the extent to which the goals established by the National Biodiesel Production and Usage Program have been reached. In relation to the goal of including biodiesel within the Brazilian energy matrix, the program...

Risks are factors of uncertainty that affect human activity on various levels. Manage them is a key issue for the success of projects that may occur. In the field of software development, an area that has inherently a high degree of uncertainty and where there is participation of various professionals involved, manage risk variables has become a ne...

This paper presents an agent-based simulation framework for supply chain (SC) planning, introducing the notion of normative agent. The analysis of the relevant literature shows that most research works carried out in this area aim to handle specific problems and contexts. Although some methodologies and more generic solutions have been proposed, th...

The regulation of specialist medical appointments represents one of the problematic areas of the Brazilian Public Health System. In this regulation process, 2 issues stand out: 1) which patients should have the highest attendance priority, and 2) which service suppliers can best resolve the specific health problem of a patient? Based on the conside...

Regulation can play an important role in effectively managing systemic risk while providing accountability to all affected governments. IMF points out weak governance structures as one of the main causes for financial/economical crisis. However, research in this area is still limited. One of the reasons is the inherent complexity of the public sect...

A DSS integrating empty and full containers transshipment operations is presented, addressing the typically unbalanced export/import containers trading problem. The problem is modeled as a network, where nodes represent customers, leasing companies, harbors and warehouses, while arcs represent transportation routes. The underlying mathematical mode...

When a public transit vehicle breaks down on a scheduled trip, one or more vehicles need to be rescheduled to serve that trip and other service trips originally scheduled for the disabled vehicle. In this paper, the vehicle rescheduling problem (VRSP) is investiaged to consider operating costs, schedule disruption costs, and trip cancellation costs...

This paper introduces and studies real-time vehicle rerouting problems with time windows, applicable to delivery and/or pickup services that undergo service disruptions due to vehicle breakdowns. In such problems, one or more vehicles need to be rerouted, in real-time, to perform uninitiated services, with the objective to minimize a weighted sum o...

This article proposes a method to collect and structure data in order to model the behavior of agents in an agent-based simulation model. This model aims to study the regulatory governance of the Brazilian financial system. In this article, the regulatory governance is understood as a phenomenon that results from several interactions and transactio...

This paper considers a truck scheduling problem in the context of solid waste collection in the City of Porto Alegre, Brazil. The problem consists of designing “good” daily truck schedules over a set of previously defined collection trips, on which the trucks collect solid waste in fixed routes and empty loads in one of several operational recyclin...

Este artigo apresenta um modelo de rede integrado combinando realocação de contêineres vazios e operações de transbordo de contêineres cheios e vazios, visando auxiliar gestores no tratamento do desequilíbrio normalmente existente entre quantidades de contêineres de exportação e de importação. Na rede, os nós representam clientes, companhias de lea...

This paper presents an integrated network model combining empty containers assignment, and empty and full containers transhipment operations, aiming to help managers to deal with the typically unbalanced trading export and import containers. In the network, nodes represent customers, leasing companies, harbors and warehouses; while arcs represent t...

Abstract This paper considers a truck schedule recovery problem in the context of solid waste collection in the city of Porto Alegre, Brazil. When a truck on a scheduled trip breaks down, a backup truck needs to be selected to serve the cargo on that trip and other trucks might be rescheduled in order to gain the minimum operating and delay costs....

When a bus on a scheduled trip breaks down, one or more buses need to be rescheduled to serve the customers on that trip with minimum operating and delay costs. The problem of reassigning buses in real-time to this cut trip, as well as to other scheduled trips with given starting and ending times, is referred to as the bus rescheduling problem (BRP...

The objective of this chapter is to describe DSS experiences in South America. The chapter describes the conception, modeling, and implementation of two DSSs. The first was designed to be applied for the operational planning of solid-waste collection. To develop the computer system, a combination of quantitative techniques was used: simulation of d...

When a bus on a scheduled trip breaks down, one or more buses need to be rescheduled to serve the customers on that trip with minimum operating and delay costs. The problem of reassigning buses in real-time to this cut trip, as well as to other scheduled trips with given starting and ending times, is referred to as the bus rescheduling problem (BRP...

When a vehicle on a scheduled trip breaks down, one or more vehicles need to be rescheduled to serve the customers on that trip with minimum operating and delay costs. The problem of reassigning vehicles in real-time to this cut trip as well as to other scheduled trips with given starting and ending times, is referred to as the vehicle rescheduling...

Disruptions in trips can prevent vehicles from executing their schedules as planned. Mechanical failures, accidents, and traffic congestion often hinder a vehicle schedule. When a vehicle on a scheduled trip breaks down, one or more vehicles need to be rescheduled to serve the passengers/cargo (if there are any) on that trip. The main objective of...

This study presents the conception, modeling, and implementation of a decision support system applied to the operational planning of solid waste collection systems, called SCOLDSS. The main functionality of the system is the generation of alternatives to the decision processes concerning: (a) the allocation of separate collection vehicles, as well...

This paper presents the conception, modeling, and implementation of a decision support system applied to the operational planning of solid waste collection systems, called SCOLDSS. The main functionality of the system is the generation of alternatives to the decision processes concerning: (a) the allocation of separate collection vehicles, as well...

O trabalho apresenta a concepção, modelagem e implementação de um sistema de apoio à decisão aplicado ao planejamento operacional da coleta seletiva de resíduos sólidos (SCOLDSS), o qual tem por funcionalidade principal a geração de alternativas ao processo decisório no que se refere à: a) alocação de veículos para a coleta seletiva, bem como deter...

Transações comerciais normalmente envolvem negociação entre vários parceiros comerciais e somente é concluída após todos os parâmetros (tais como, preço, qualidade do produto e prazos de entrega) relativos a negociação terem sido avaliados. Esse processo pode demandar bastante tempo, considerando os cenários de negociação atuais. A Tecnologia da In...

O artigo apresenta a concepção, desenvolvimento e validação de um modelo de simulação de eventos discretos aplicado ao controle da distribuição da coleta seletiva de resíduos sólidos. O trabalho tem por funcionalidade principal à geração de alternativas ao processo decisório no que se refere à determinação da quantidade diária de resíduos sólidos a...

A decision support system (DSS) for modeling and solving the recyclable waste collection operational planning is presented. The computer system has the following objectives: a) to define the vehicles' allocation and routing; b) to determine the quantity of solid waste to be sent to each waste recyclable trial unit; and c) to generate operational sc...

This paper describes a state space representation for sequencing and routing flexibility in manufacturing systems. Routing flexibility is represented using five different stages as follows: (i) Precedence Graph of Operations; (ii) State Transition Graph of Manufacturing Operation Sequences; (iii) State Transition Graph of Manufacturing Operation Ro...

Investments in Information Technology (IT) are in essence strategic decision processes. However, many decision makers, given the complexity of their problems, end up by either reducing them to an approach that is usually monetary to the detriment of those possibly related to strategic benefits associated with IT. This fact is a consequence of the l...

O artigo apresenta um sistema de apoio à decisão aplicado ao planejamento operacional da coleta seletiva de resíduos sólidos (SCOLDSS), o qual tem por funcionalidade principal à geração de alternativas ao processo decisório no que se refere á: (a) alocação de veiculos para a roleta seletiva, bem como o roteiro a ser percorrido pelos mesmos e, (b} a...

Postal companies around the world have been seeking methods to support their operational practices in order to keep or increase their market share. The Brazilian Mail and Telegraph Company (ECT) has a portfolio of products and services to offer to its customers through several similar postal offices all over Brazil. The units use several resources...

O artigo apresenta um sistema de apoio à decisão aplicado ao planejamento operacional da coleta seletiva de resíduos sólidos (SCOLDSS), o qual tem por funcionalidade principal à geração de alternativas ao processo decisório no que se refere á: (a) alocação de veículos para a coleta seletiva, bem como o roteiro a ser percorrido pelos mesmos e, (b) a...

Este artigo descreve uma representação em espaço de estados para a flexibilidade de roteamento em sistemas de manufatura. A flexibilidade de roteamento é representada em três níveis de detalhamento, como segue: (i) grafo de precedências; (ii) grafo de transição de estados para a flexibilidade de seqüência; e (iii) grafo de transição de estados para...

Manufacturing process planning in flexible manufacturing environments requires a highly efficient computerized representation, since the number of different alternatives grows rapidly as the level of flexibility of the manufacturing systems increases. Furthermore, in order to recommend a good manufacturing plan, it is necessary to be capable of gen...

Mass customization (MC) is an emergent concept in industry intended to provide customized products or services through flexible process in high volumes and at reasonably low costs. Product customization is an important strategy for accomplishing customer satisfaction with exclusive products at reasonable prices. This paper proposes a decision suppo...