Rui Borges Lopes

Location-arc routing problem: Heuristic approaches and test instances

Location-routing is a branch of locational analysis that takes into account distribution aspects. The location-arc routing problem (LARP) considers scenarios where the demand is on the edges rather than being on the nodes of a network (usually a road network is assumed). Examples of such scenarios include locating facilities for postal delivery, garbage collection, road maintenance, winter gritting and street sweeping. This paper presents some heuristic approaches to tackle the LARP, as well as some proposals for benchmark instances (and corresponding results). New constructive and improvement methods are presented and used within different metaheuristic frameworks. Test instances were obtained from the capacitated arc routing problem (CARP) literature and adapted to address the LARP.

A simple and effective evolutionary algorithm for the capacitated location-routing problem

This paper proposes a hybrid genetic algorithm (GA) to solve the capacitated location-routing problem. The proposed algorithm follows the standard GA framework using local search procedures in the mutation phase. Computational evaluation was carried out on three sets of benchmark instances from the literature. Results show that, although relatively simple, the proposed algorithm is effective, providing competitive results for benchmark instances within reasonable computing time. New chromosome representation and crossover operator for location-routing problems.New evolutionary algorithm for solving the capacitated location-routing problem.The proposed algorithm is able to obtain high quality results in short run times.

Application of Lean Manufacturing Tools in the Food and Beverage Industries

Recent years have shown an increasing use of lean manufacturing (LM) principles and tools in several industrial sectors. Already a well-established management philosophy, it has shown numerous successful applications even outside production environments. This work presents the application of some LM tools, and the corresponding shift in philosophy, in two Portuguese companies of the food and beverage industries. Main implementation issues are presented and discussed; followed by the results obtained from the application of LM tools in the production system of these companies. Significant gains are obtained in both companies and, more importantly, it instills a continuous improvement culture and increases production flexibility while reducing lead times.

Information Visualization in Facility Location and Vehicle Routing Decisions

Facility location and vehicle routing are amongst the most important logistic decisions in today’s organizations. These aspects are intertwined and, in some cases, should be addressed in an integrated way (giving rise to the location-routing approach). A decision support tool that can make easier the visualization (and editing) of information regarding these problems is becoming increasingly important as: it enables to further understand the problem at hand; and, at the same time, it fosters better communication of the decisions in a way easier to understand by the general public. This paper presents some concepts for information visualization on the problems arisen by the aforementioned decisions, which have been incorporated in a decision support tool and tested using usability evaluation methods.

Covering-Based Rural Road Network Methodology for Hilly Regions of Developing Countries: Application in Nepal

AbstractThis work provides a practical approach for the definition of rural road networks in hilly regions of developing countries. The proposed methodology enables the determination of obligatory ...

LORE, A Decision Support Tool for Location, Routing and Location-Routing Problems

LOcation Routing Exploration (LORE) is a decision support tool for addressing location, routing and location-routing problems. In this paper the LORE tool will be presented, and its main characteristics addressed. Among the main features of the tool is the ability to support a variety of problems currently being studied in the location and routing literature (due to the proposed data structure), and the graphical user interface (GUI). The data structure will be presented being provided an explanation on how it can support related problems. The GUI main goal is not only to aid the solution-finding process but also to foster greater insight into the problem(s) at hand. To that extent, the GUI, developed to fit the target user’s profile and intended tasks, is presented, namely data input and visualization features.

Visually Supporting Location and Routing Decisions in Tourist Trip Planning: An Exploratory Approach

This paper presents a new web-based tool which allows the visualization of real online data combined with other relevant information for supporting tourist trip planning decisions. The main decisions intended supporting concern location, namely place to stay, and routing, which sites to visit and the best sequence to visit them. As they are interconnected, location and routing should be addressed simultaneously. The integrated view has been addressed in the literature from a modeling and solution approach perspective, however, lack of comprehensive visualization solutions to help the decision-making process may hinder their real-world applicability. Although this work focuses on a specific application, the tool presented herein can support other real-world location-routing applications (e.g. in logistics). It enables interactive visualizations and navigation in web browsers, and provides functionalities considered important in the context of tourist trip planning. Focus group and usability evaluation were used throughout the development of the tool for collecting information and testing visualizations and interactions.

A Tool for Visually Exploring Multi-objective Mixed-Integer Optimization Models

Multi-objective optimization models have been increasingly used as optimal decisions are searched in settings considering several conflicting objectives. In these cases compromises must be made and often a large number of non-dominated optimal solutions exist. From these solutions decision-makers must find the preferred one. This is a difficult task both from a computational and cognitive point of views, as it requires several solutions to be obtained and compared. An interactive visualization tool for fully understanding the best trade-offs is therefore becoming increasingly important. This paper proposes visualization solutions, implemented in a tool, for aiding decision-makers in finding the preferred solution in multi-objective optimization problems.