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Publications

Publications by SEM

2014

Benchmarking dos serviços dos hospitais portugueses: uma aplicação de data envelopment analysis

Authors
Castro, RAS; Portela, CS; Camanho, AS;

Publication
Investigação operacional em ação: casos de aplicação

Abstract

2014

Models for capacitated lot-sizing problem with backlogging, setup carryover and crossover

Authors
Belo Filho, MAF; Toledo, FMB; Almada Lobo, B;

Publication
JOURNAL OF THE OPERATIONAL RESEARCH SOCIETY

Abstract
Setup operations are significant in some production environments. It is mandatory that their production plans consider some features, as setup state conservation across periods through setup carryover and crossover. The modelling of setup crossover allows more flexible decisions and is essential for problems with long setup times. This paper proposes two models for the capacitated lot-sizing problem with backlogging and setup carryover and crossover. The first is in line with other models from the literature, whereas the second considers a disaggregated setup variable, which tracks the starting and completion times of the setup operation. This innovative approach permits a more compact formulation. Computational results show that the proposed models have outperformed other state-of-the-art formulation.

2014

A performance estimation framework for complex manufacturing systems

Authors
Almeida, A; Azevedo, A;

Publication
FAIM 2014 - Proceedings of the 24th International Conference on Flexible Automation and Intelligent Manufacturing: Capturing Competitive Advantage via Advanced Manufacturing and Enterprise Transformation

Abstract
To cope with today market challenges and guarantee adequate competitive performances, companies have been decreasing their products life cycles, as well as increasing the number of product varieties and respective services available on their portfolio. Consequently, it has been observed an increasing in complexity in all domains, from product and process development, factory and production planning to factory operation and management. This reality implies that organizations should be able to compile and analyze, in a more agile way, the immense quantity of data generated, as well as apply the suitable tools that, based on this knowledge, will supports stakeholders to take decision envisioning future performance scenarios. Aiming to pursuing this vision was developed a proactive performance management framework, composed by a performance thinking methodology and a performance estimation engine. While the methodology developed is an extension of the Systems Dynamics approach for complex systems' performance management, on the other hand, the performance estimation engine is an innovative IT solution responsible by capturing lagging indicators, as well as estimate future performance behaviors. As main outcome of this research work, it was demonstrated that following a systematic and formal approach, it is possible to identify the feedback loops and respective endogenous and exogenous variables responsible by hindering the systems behavior, in terms of a specific KPI. Moreover, based on this enhanced understanding about manufacturing systems behavior, it was proved to be possible to estimate with high levels of confidence not only the present but also future performance behavior. From the combination of both qualitative and quantitative approaches, it was explored an enhanced learning machine algorithm capable to specify the curve of behavior, characteristic from a specific manufacturing system, and thus estimate future behaviors based on a set of leading indicators. In order to achieve these objectives, both Neural Networks and Unscented Kalman Filter for nonlinear estimation were applied. Important results and conclusions were extracted from an application case performed within a real automotive plant, which demonstrated the feasibility of this research towards a more proactive management approach.

2014

Reference model for collaborative manufacturing of customised products: applications in the fashion industry

Authors
Carneiro, L; Shamsuzzoha, AHM; Almeida, R; Azevedo, A; Fornasiero, R; Ferreira, PS;

Publication
PRODUCTION PLANNING & CONTROL

Abstract
In the recent years, it has been confirmed both by theory and by practice that organisational models need to include networking strategies to cope with the current competitive environment. Different collaboration levels can characterise supply chains, virtual organisations (VO) and business communities; however, managing different networking scenarios is extremely important to allow SMEs to respond to market opportunities, ensuring a quick response, unique products with competitive prices and high product quality. This paper proposes an innovative methodological approach to support collaboration amongst SMEs for customised product design and manufacturing based on the VO concept. The work is based on mapping the methodology with the most important processes characterising the life of a VO and defining the operative practices to be performed within this type of network. This paper presents two case studies in the fashion industry, where the proposed approach for network management was tested and analysed.

2013

Predictive production planning in an integrated pulp and paper mill

Authors
Figueira, G; Furlan, M; Almada Lobo, B;

Publication
IFAC Proceedings Volumes (IFAC-PapersOnline)

Abstract
Disturbance Management is a major issue in process industries like the pulp and paper (P&P) industry. In this paper, a case study in an integrated P&P mill is examined. Production plans for the whole mill need not only to be optimized concerning company's indicators, but also to be robust so that disturbances can be avoided. We present a simulation-optimization approach that generates plans, correctly weighting their quality (regarding various indicators) and robustness. A discrete-event simulation model replicates the dynamics of implementation and adaptation of production plans in practice. The simulation model gives then feedback to optimization, in order to enhance the analytical model, which is thus able to generate robust plans. © IFAC.

2013

Business process monitoring and management in virtual enterprise through interactive user interface layer

Authors
Shamsuzzoha, A; Ferreira, F; Azevedo, A; Faria, J; Helo, P;

Publication
Lecture Notes in Mechanical Engineering

Abstract
This research provides mechanisms that facilitate to monitor and manage of Virtual Enterprise (VE) collaborative business processes in an efficient and effective way. First, it shows a self-contained process monitoring tool specification that contains the following main functionalities: events capturing from a workflow engine, business activity monitoring, process analytics and monitoring rules definition and evaluation. An interactive user interface layer in the form of dashboard is then highlighted within the scope of this research with the objective to monitor the VE operational processes. The dashboard will be the integration platform for a set of components that allow the establishment and operation of VE successfully. This platform enables a seamless integration of business processes and provides an endto-end ICT solution among the VE member organizations. The work presented in this paper is developed within the scope of the European Commission NMP priority of the Seventh RTD Framework Programme for the ADVENTURE (ADaptive Virtual ENterprise ManufacTURing Environment) project. © Springer International Publishing Switzerland 2013.

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