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Publications

Publications by CEGI

2019

Capacitated Vehicle Routing Problem with Heterogeneous Fixed Proprietary Fleet and Outsourcing Delivery—A Clustering-Based Approach

Authors
Bertoluci, R; Ramos, AG; Lopes, M; Bastos, J;

Publication
Springer Proceedings in Mathematics and Statistics

Abstract
This paper describes a solution method that was created with the objective of obtaining a more efficient finished goods distribution process for a food industry company. The finished goods distribution process involves the use of the companys own fleet to serve a specific group of customers, and the use of outsourcing transportation services that can make direct and transshipment customer deliveries. The complexity of the problem is due to the need to decide which customers should be served by each of the outsourcing transportation services, direct or transshipment, and to find cost efficient solutions for the multiple vehicle routing problems created. First, an original clustering method consisting of a logical division of the customer orders using a delivery ratio based on the transportation unit cost, distance and order weight, is used to define customer clusters by service type. Then, an exact method based on a mixed integer programming model, is used to obtain optimal vehicle routing solutions, for each cluster created. The solution method for the company real instances, proved able to reach the initial proposed objectives and obtain promising results that suggest an average reduction of 34% for the operational costs, when compared to the current distribution model of the company. © 2019, Springer Nature Switzerland AG.

2019

Multiple vehicle synchronisation in a full truck-load pickup and delivery problem: A case-study in the biomass supply chain

Authors
Soares, R; Marques, A; Amorim, P; Rasinmaki, J;

Publication
EUROPEAN JOURNAL OF OPERATIONAL RESEARCH

Abstract
The search for higher efficiency in transportation planning processes in real life applications is challenging. The synchronisation of different vehicles performing interrelated operations can enforce a better use of vehicle fleets and decrease travelled distances and non-productive times, leading to a reduction of logistics costs. In this work, the full truck-load pickup and delivery problem with multiple vehicle synchronisation (FT-PDP-mVS) is presented. This problem is motivated by a real-life application in the biomass supply chain "hot-system", where it is necessary to simultaneously perform chipping and transportation operations at the forest roadside. The FT-PDP-mVS consists in determining the integrated routes for three distinct types of vehicles, which need to perform interrelated operations with minimum logistics costs. We extend existing studies in synchronisation of multiple routes by acknowledging several synchronisation aspects, such as operations and movement synchronisation. A novel mixed integer programming model (MIP) is presented, along with valid inequalities to tighten the formulation. A solution method approach is developed based on the fix-and-optimise principles under a variable neighbourhood decomposition search. Results of its application to 19 instances based on a real-world case-study demonstrate its performance. For a baseline instance, the synchronisation aspects tackled in this problem allowed for significant gains when compared to the company's current planning approach. Furthermore, the proposed approach can enhance planning and decision making processes by providing valuable insights about the impact of key parameters of biomass logistics over the routing results.

2019

Assessment and optimization of sustainable forest wood supply chains - A systematic literature review

Authors
Santos, A; Carvalho, A; Barbosa Povoa, AP; Marques, A; Amorim, P;

Publication
FOREST POLICY AND ECONOMICS

Abstract
When it was first introduced, the concept of sustainability in the forestry sector had a narrow focus on sustainable wood production. Since then, this concept has evolved and it now considers now the three sustainability dimensions (economic, environmental and social) of the whole forest wood supply chain. The main objective of this study is then to review assessment and optimization studies that consider the forest wood supply chain and at least one of the sustainability dimensions. To accomplish this goal, a total number of 188 papers, published in English-speaking peer-reviewed journals from 1995 to 2017, were reviewed. These papers have been classified according to the sustainability dimensions explored, the stakeholder's involvement, the modeling approaches applied, the supply chain decision levels treated, the uncertainty inclusion, and case study analyzed. Most of the studies reviewed (84.6%) considered only two sustainability dimensions: economic (31.9%), environmental (13.8%), or a combination of both (38.8%). The first study including the three sustainability dimensions was published in 2005. Most of the studies reviewed (64.9%) focus on the bioenergy industry in Europe and North America, due to the growing interest in using biomass to substitute fossil fuels in energy production. The final part of the paper presents the identified specific features of sustainable forest wood supply chains and discusses a future research agenda in the area.

2019

QUALITY ASSURANCE OF DOCTORAL EDUCATION IN PORTUGAL: A RETROSPECTIVE OF THE FIRST ACCREDITATION CYCLE

Authors
Migueis, V; Cardoso, S; Rosa, MJ; Cabral, JS;

Publication
EDULEARN19: 11TH INTERNATIONAL CONFERENCE ON EDUCATION AND NEW LEARNING TECHNOLOGIES

Abstract
In the last decades, the assurance of doctoral education's quality and their respective external quality assurance (QA) systems have been on the agenda of many European countries. Portugal is no exception, with doctoral education being envisaged by the national study programmes' accreditation system. This study aims to discuss both the forms assumed by the QA of doctoral education within the scope of a tightly regulated system, such as the Portuguese one, as well as the effects or impact of such a system in this education level. In trying to explore this impact, particular attention is given to the accreditation results (full accreditation, conditional accreditation and non-accreditation) of the doctoral programmes according to their scientific area and higher education sector (public and private). Overall it is possible to conclude that the Portuguese QA system has been contributing to the reorganisation of doctoral education, both by excluding programmes that do not meet a set of minimum quality criteria and by promoting the enhancement of the remaining programmes, through the enforcement of improvement measures. This reorganisation seems to differently affect doctoral programmes from distinct scientific areas as well as from private and public institutions.

2019

With Whom Transport Operators Should Partner? An Urban Mobility and Services Geolocation Data Analysis

Authors
Ferreira, MC; Dias, TG; e Cunha, JF;

Publication
Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, LNICST

Abstract
Automated Fare Collection (AFC) systems produce a large amount of very detailed data, which analysis may be very useful to authorities and transport planners to define future service delivery strategies. Such analysis can be further improved by relating to other data sources, such as points-of-interest (POI) data. As a result public transport operators are able to identify the city service providers with whom it would be more interesting to establish partnerships and propose joint value propositions benefiting both service providers. The objective of such partnerships is to attract new customers and retain those that already exist by providing combined offers, discounts or loyalty schemes. The potential of such analysis is demonstrated by using data related to the city of Porto, Portugal. This study relies on two different data sources: AFC system data and points-of interest data. Urban mobility data is used to identify mobility patterns of different segments of passengers and points-of-interest data is used to analyse the type of services that are likely to concentrate around public transport stations. The results allowed to identify the potential city services to establish partnerships according to the mobility profiles of passengers and the concentration levels of services around public transport stations. © 2019, ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering.

2019

Usability Evaluation of a Public Transport Mobile Ticketing Solution

Authors
de Amorim, DM; Dias, TG; Ferreira, MC;

Publication
HUMAN SYSTEMS ENGINEERING AND DESIGN, IHSED2018

Abstract
Many public transport mobile ticket solutions have arisen but new technologies can face difficulties when launched for a number of reasons that are directly addressed by usability evaluation - a central process in developing usable, hence useful high quality systems with which humans can interact. This paper presents a usability testing performed in context of use of a recently developed public transport mobile ticketing solution for the Metropolitan Area of Porto, Portugal. The objective was to determine if the application is easy to use and navigate for the average user and to generate valuable suggestions for making the app more user-friendly and tasks such as using public transport services and understanding fares quicker and less complicated. Along with problems detected, a list of recommendations by order of importance for improving usability aspects of the mobile application was provided. This study aims to inform developers about usability practices for making mobile ticketing solutions easier to use and stimulate its wider adoption.

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