Denis Borenstein

Mass customization: Literature review and research directions

Abstract Mass customization relates to the ability to provide individually designed products and services to every customer through high process flexibility and integration. Mass customization has been identified as a competitive strategy by an increasing number of companies. This paper surveys the literature on mass customization. Enablers to mass customization and their impact on the development of production systems are discussed in length. Approaches to implementing mass customization are compiled and classified. Future research directions are outlined.

Towards a practical method to validate decision support systems

Abstract Validation is important to the decision-making success and to the continued use of a Decision Support System (DSS). Without proper validation, DSSs may cause costly errors. However, little is known about available effective methods to validate such computer-based systems. In this paper a new method to validate DSS is presented. The approach combines several validation methods developed to validate Operations Research/Management Science (OR/MS) models and expert systems validation frameworks to define a practical guidance for the validation stage of the DSS development. A case study illustrates the effectiveness of the developed method.

Real-time vehicle rerouting problems with time windows

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 of operating, service cancellation and route disruption costs. A Lagrangian relaxation based-heuristic is developed, which includes an insertion based-algorithm to obtain a feasible solution for the primal problem. A dynamic programming based algorithm solves heuristically the shortest path problems with resource constraints that result from the Lagrangian relaxation. Computational experiments show that the developed Lagrangian heuristic performs very well.

A framework to support customer-company interaction in mass customization environments

In the new and emerging mass customization (MC) strategy, where companies and clients cooperate either to design or to assemble a customized product or service, there exists a great need for a mechanism to manage and control information flow among the collaborative business units. The aim of this paper is to present the design and implementation of an information system framework for agile interactions between companies and customers in an MC environment. The underlying philosophy of this framework is to combine Internet-based technology and object-oriented programming (OOP), and offer smart tools that allow customers to interact rapidly and responsively with MC production systems.

A DSS for integrated distribution of empty and full containers

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 model operates in stages, first prioritizing and adjusting full containers demands considering available empty containers supplies, and then statically optimizing costs. Transportation routes are registered and dynamically controlled, cyclically, for a given time horizon. The DSS is flexible, allowing several parameters to be configured. Experimental examples using randomly generated parameters were conducted to evaluate the effectiveness of the system.

A decision support system for the single-depot vehicle rescheduling problem

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 the vehicle rescheduling problem (VRSP) is to minimize operation and delay costs, while serving the passengers/cargo on the disrupted trip and completing all remaining trips that include the disrupted one. We report on a prototype decision support system (DSS) that recommends solutions for the single-depot rescheduling as well as vehicle scheduling (VSP) problems, since VRSP is closely related to VSP. The system was designed for human schedulers to obtain optimal vehicle assignments and reassignments. An experimental study, using randomly generated data, shows the efficiency of the developed algorithm. A real world problem, which involves the solid waste collection operational planning for a Brazilian city, is selected as the case study to illustrate the effectiveness of the developed DSS.

A fuzzy-Bayesian model for supplier selection

The selection supplier problem has received a lot of attention from academics in recent years. Several models were developed in the literature, combining consolidated operations research and artificial intelligence methods and techniques. However, the tools presented in the literature neglected learning and adaptation, since this decision making process is approached as a static one rather than a highly dynamic process. Delays, lack of capacity, quality related issues are common examples of dynamic aspects that have a direct impact on long-term relationships with suppliers. This paper presents a novel method based on the integration of influence diagram and fuzzy logic to rank and evaluate suppliers. The model was developed to support managers in exploring the strengths and weaknesses of each alternative, to assist the setting of priorities between conflicting criteria, to study the sensitivity of the behavior of alternatives to changes in underlying decision situations, and finally to identify a preferred course of action. To be effective, the computational implementation of the method was embedded into an information system that includes several functionalities such as supply chain simulation and suppliers databases. A case study in the biodiesel supply chain illustrates the effectiveness of the developed method.

Decision Support System for Product Configuration in Mass Customization Environments

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 support system for facilitating design and customer collaboration in the process of selecting product configuration in MC environments. The system integrates object-oriented programming, multiattribute decision analysis, and integer linear programming to support product/service customization where customer choice is managed by the relative relevance of a set of attributes as well as a set of component combinations offered by the company, and restrained by a set of technical, aesthetical, and financial constraints defined interactively by designers and customers. The integration of these models results in the representation of the MC business process taking into account simultaneously the technical, explicit, and objective view taken by designers and the customer’s view based on intentions and perceptions. Using the system, the customer can define rules and provide information that can be used to represent tacit knowledge which is incorporated in an integer linear programming (ILP) model that optimizes the utility of a specific customer. As a result, the computer system is capable of implementing in an explicit, dynamic, and flexible way the cognitive process that characterizes the product configuration in MC strategy. The DSS can be considered as a concurrent engineering environment for MC production systems. A simple case study is presented that demonstrate how the program is utilized and the type of output it provides.

Measuring the efficiency of Brazilian post office stores using data envelopment analysis

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 with different intensities, currently having their performance evaluated by a single economical factor: revenues over expenses. We propose a performance evaluation method based on data envelopment analysis (DEA), a linear programming technique that makes it possible to include other factors beyond the simplistic, purely economical approach. The objectives of this paper are to define which factors can be used to evaluate the units; to define sets of similar units that develop the same functions, differing only in the intensity of resource usage; to generate, through the technique, the results of the evaluation process obtained from the quantitative factors defined, providing a sensitivity analysis, and to provide useful information to help managers in their decision‐making process.

A directed acyclic graph representation of routing manufacturing flexibility

Abstract This paper describes a graph-based model for representing routing flexibility in manufacturing systems. Routing flexibility is represented using direct acyclic graphs which enumerate all possible manufacturing operation sequences that can be applied to a certain part. Such a representation enables efficient planning of operations and machines according to different factors such as complexity of manipulation of the parts and current factory conditions. The routing representation is obtained through an interactive approach in which an expert human designer defines the specifications of a part and, using a software package developed by the author, constructs the routing models. The routing flexibility was embedded within a simulation model, offering a powerful analysis tool of flexible automation, both evaluating and measuring the effects of flexibility upon a manufacturing systems behaviour. An example illustrates the applicability and potentiality of the flexibility model developed.