CESE

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This service promotes the use, by small and medium-sized companies, of innovative solutions based on information systems, communications and electronics.

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    An Advanced Agent-Based Order Planning System for Dynamic Networked Enterprises
    ( 2004) César Toscano ; Jorge Pinho de Sousa ; Américo Azevedo ; António Lucas Soares
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    Cooperative planning in dynamic supply chains
    ( 2005) César Toscano ; Jorge Pinho de Sousa ; Américo Azevedo
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    Dynamic VRP in pharmaceutical distribution - a case study
    ( 2006) José Miguel de Magalhães ; Jorge Pinho de Sousa
    In recent years, the pharmaceutical sector has gone through deep changes, partially due to the ageing of the population and to the increasing of costs in health care services. With margins that are getting lower and lower, the drug distribution problem to pharmacies has become much more important, particularly in large metropolitan areas. As pharmacies demand shorter delivery times, vehicle routing and scheduling problems become harder for distributors. It is recognized that the traditional system based on fixed routes does not fulfil the expectations of pharmacies and may, in some cases, be quite inefficient for distributiors. In this work, a case study has been carried out and a change of the traditional approach is proposed, by adopting a system of variable routes that are dynamically designed, based on orders that are constantly arriving along the day. A dynamic algorithm is therefore proposed, meant to be run several times a day. It has four phases: first, a clustering of th
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    Scheduling in the Textile Industry
    ( 2007) Ana Santos ; José Soeiro Ferreira
    The Textile Industry faces specific and critical scheduling difficulties along with the planning and control of production in the weaving sections. Generally the textiles are produced to order and the whole production must observe the times of delivery agreed with the clients. Therefore it is necessary to allocate the existing looms to the processing of tasks, the fabric types to be produced. The case of one of the largest Portuguese textile companies (manufacturing mainly for exportation) is presented. The situation involves more than 100 looms with different characteristics. The parallel machines scheduling problems are complex due to various reasons such as: specific sets of fabric can only be produced on certain looms, depending on the equipment - a specific warp chain; there are limits on the length of the threads to wind round the cylinders of the looms - setups must be taken into account; a certain loom may used to produce various fabric types, but then its configuration must be changed, another (external) setup occurs due to the replacement of a warp chain, which may take at least 5 hours, and so on. The problems were modelled as Combinatorial Optimisation and several criteria were discussed. Feasible solutions were generated to test all the conditions and restrictions and to facilitate the discussion with the technicians of the company. The optimisation procedure is based on Tabu Search - the procedure will be described. Computational results will also be presente
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    Single machine multi-product capacitated lot sizing with sequence-dependent setups
    ( 2007) Diego Klabjan ; Bernardo Almada-Lobo ; Maria Antónia Carravilla ; José Fernando Oliveira
    In production planning in the glass container industry, machine-dependent setup times and costs are incurred for switch overs from one product to another. The resulting multi-item capacitated lot-sizing problem has sequence-dependent setup times and costs. We present two novel linear mixed-integer programming formulations for this problem, incorporating all the necessary features of setup carryovers. The compact formulation has polynomially many constraints, whereas the stronger formulation uses an exponential number of constraints that can be separated in polynomial time. We also present a five-step heuristic that is effective both in finding a feasible solution (even for tightly capacitated instances) and in producing good solutions to these problems. We report computational experiments.
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    UNDERSTANDING USERS' RESPONSE TO ONTOLOGY BASED SYSTEMS IN THE CONTEXT OF AN ENTERPRISE SPONSORED VIRTUAL COMMUNITY
    ( 2007) Joana Fernandes ; Carla Pereira ; Manuel Fernando Silva ; António Lucas Soares
    This paper aims at presenting the preliminary results of a research work that seeks to understand the users' response to semantic based technologies, in the context o/, enterprise sponsored virtual communities. The research follows a qualitative methodolog}' based on an action research approach. It particlllar~v focuses on the socio-cognitive processes that underlie usel:~' learning and acquisition methods when training and interacting with a new knowledge management approach based on semantically enabled technologies in a collaborative, and sometimes virtual. learning/working environment. The outcomes of this research are expected to provide an assessment frameworkfor a deeper level understanding of the cognition process in what concerns the evolution of individual~~ knowledge. opinions. beliefs. and thoughts abuut untology based systems.
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    High performance collaborative networks: a realistic innovation or just an academic desire?
    ( 2007) Jorge Pinho de Sousa ; Rui Patrício ; Luís Carneiro ; António Lucas Soares ; Adília Isabel Alves ; Ricardo Madureira
    This paper presents the preliminary findings of a research project aiming at the definition of the conditions required for the creation and management of high-performance collaborative business networks in Northern Portugal. Given the industrial context of the region the emergence of such networks would be innovative in itself. The project adopted a multiplecase study research strategy, based on data from 40 semi-structured interviews. The preliminary results of the study include: 1) operational definitions based on an extensive literature review; 2) a conceptual framework for the analysis of high-performance collaborative networks; and 3) recommendations for the creation and on-going management of such networks.
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    Improving the quality of collaboration requirements for information management through social networks analysis
    ( 2007) Carla Pereira ; António Lucas Soares
    The right choice of the method of organizational analysis to use is a key factor in the process of requirements analysis and specification of an information system. Although a high number of approaches of organizational analysis exist, the choice of the most appropriate option for each concrete case will influence the quality of the results obtained in the analysis of requirements and consequent specification. This paper present a new way for organizational analysis to improve the quality of the requirements of systems that support information management and where collaboration is an important aspect. This is achieved through the application of the social network analysis approach, applied to refine, classify and prioritize the requirements for collaboration and information management in an organization. The paper begins by analysing shortly content management systems and wiki systems as IT platforms for collaboration and information management. After having described the method, a practical case of application of SNetCol method to a R&D institution is presented. The paper finishes by presenting the results of the evaluation of the two particular technological options considered for satisfying the specified requirements are described.
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    Simple Meta-heuristics using the simplex algorithm for non-linear programming
    ( 2007) João Pedro Pedroso
    In this paper we present an extension of the Nelder and Mead simplex algorithm for non-linear programming, which makes is suitable for both unconstrained and constrained optimisation. We then explore several extensions of the method for escaping local optima, and which make it a simple, yet powerful tool for optimisation of nonlinear functions with many local optima. A strategy which proved to be extremely robust was random start local search, with a correct, though unusual, setup. Actually, for some of the benchmarks, this simple meta-heuristic remained as the most e®ective one. The idea is to use a very large simplex at the begin; the initial movements of this simplex are very large, and therefore act as a kind of ¯lter, which naturally drives the search into good areas. We propose two more mechanisms for escaping local optima, which, still being very simple to implement, provide better results for some dif- ¯cult problems.
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    Cutting and packing
    ( 2007) José Fernando Oliveira ; Gerhard Wäscher
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    Critical technologies for the North of Portugal in 2015: the case of ITCE sectors - information technologies, communication and electronics
    ( 2007) Luís Carneiro ; António Carrizo ; Marta Tavares
    The Commission for Coordination and Regional Development of the North of Portugal (CCDR-N) promoted NORTINOV 2015, a project created to define a regional innovation strategy for the North of Portugal based on automotive clusters and Information Technology, Communication and Electronics (ITCE) clusters. Accordingly, it developed a technology forecast for the year 2015 in order to help the North of Portugal cope with the intensifying global competition and rapid technological changes. This paper describes the methodology used to identify critical technologies for the regional economy of the North of Portugal under the project NORTINOV 2015. It involved three main steps: technology identification and study, in which a list of emerging technologies was implemented; refinement of emerging technologies, in which 90 technologies were identified and finally, classification and hierarchisation of technologies, in which 30 technologies were identified as critical for the crafting of regional innovation strategy. In this final step, a workshop involving major stakeholders of the three clusters under study played a major role.
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    Interoperability in Collaborative Networks: An innovative approach for the shoe up-stream business segment
    ( 2007) Claudia Chituc ; César Toscano ; Américo Azevedo
    The development of information and communication technologies determined enterprises to adapt their way of undertaking business, from traditional practices to e-business. In this context, achieving seamless interoperability among heterogeneous entities becomes a critical issue. The goal of this article is to present an innovative two-layered operational infrastructure aiming at achieving seamless interoperability in shoe manufacturing up-stream segment, developed within the scope of CEC-made-shoe European Integrated Project.
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    Ontology Engineering in Virtual Breeding Environments
    ( 2007) Dora Pereira ; António Lucas Soares ; Hugo Miguel Ferreira
    This paper proposes a new method for managing the use of ontologies in the context of a Virtual Breeding Environment. This research work focus is on the dissolution phase of a Virtual Enterprise or Collaborative Network, where ontology segmentation techniques are user to enrich the VBE's ontology library. Firstly, an overview of the process of ontology composition and decomposition is given and the ontology library system adopted described. Then, the ontologies' ranking and classification method is described, explaining a set of metrics inspired in social network approaches. Finally, the results of preliminary tests are discussed.
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    Heuristics for a dynamic rural postman problem
    ( 2007) José Soeiro Ferreira ; António Miguel Gomes ; Luís Miguel Moreira ; José Fernando Oliveira
    This paper presents a very special cutting path determination problem appearing in a high precision tools factory, and provides two new heuristics for its resolution. Particular features of both the cutting process, and of the material to be cut, bring in a set of unusual constraints, when compared with other cutting processes, which confer additional complexity and originality to the problem. In particular, this is a matter of practical and economic relevance, since the solution methods are intended to be implemented in a real-life industrial environment. The concept of dynamic graph is exploited to deal with the arc routing problem under study, which is modelled as a dynamic rural postman problem. The constructive heuristics developed, the “higher up vertex heuristic” (HUV) and the “minimum empty path heuristic” (MEP) are tested with real data sets.
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    The geometry of nesting problems: A tutorial
    ( 2008) José Fernando Oliveira ; Julia A. Bennel
    Cutting and packing problems involving irregular shapes is an important problem variant with a wide variety of industrial applications. Despite its relevance to industry, research publications are relatively low when compared to other cutting and packing problems. One explanation offered is the perceived difficulty and substantial time investment of developing a geometric tool box to assess computer generated solutions. In this paper we set out to provide a tutorial covering the core geometric methodologies currently employed by researchers in cutting and packing of irregular shapes. The paper is not designed to be an exhaustive survey of the literature but instead will draw on the literature to illustrate the theory and implementation of the approaches. We aim to provide a sufficiently instructive description to equip new and current researchers in the area to select the most appropriate methodology for their needs.
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    Hierarchical Clustering of Time-Series Data Streams
    ( 2008) João Pedro Pedroso ; Pedro Pereira Rodrigues ; João Gama
    This paper presents and analyzes an incremental system for clustering streaming time series. The Online Divisive-Agglomerative Clustering (ODAC) system continuously maintains a tree-like hierarchy of clusters that evolves with data. ODAC uses a top-down strategy. The splitting criterion is a correlation-based dissimilarity measure among time series, splitting each node by the farthest pair of streams, which defines the diameter of the cluster. In stationary environments expanding the structure leads to a decrease in the diameters of the clusters. The system uses a merge operator, which agglomerates two sibling clusters, in order to react to changes in the correlation structure between time series. The split and merge operators are triggered in response to changes in the diameters of existing clusters. The system is designed to process thousands of data streams that flow at high-rate. The main features of the system include update time and memory consumption that do not depend on the number of examples in the stream. Moreover, the time and memory required to process an example decreases whenever the cluster structure expands. Experimental results on artificial and real data assess the processing qualities of the system, suggesting competitive performance on clustering streaming time series, exploring also its ability to deal with concept drift.
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    Fast solutions for UC problems by a new metaheuristic approach
    ( 2008) Ana Viana ; Jorge Pinho de Sousa ; Manuel Matos
    Due to its combinatorial nature, the Unit Commitment problem has for long been an important research challenge, with several optimization techniques, from exact to heuristic methods, having been proposed to deal with it. In line with one current trend of research, metaheuristic approaches have been studied and some interesting results have already been achieved and published. However, a successful utilization of these methodologies in practice, when embedded in Energy Management Systems, is still constrained by the reluctance of industrial partners in using techniques whose performance highly depends on a correct parameter tuning. Therefore, the application of metaheuristics to the Unit Commitment problem does still justify further research. In this paper we propose a new search strategy, for Local Search based metaheuristics, that tries to overcome this issue. The approach has been tested in a set of instances, leading to very good results in terms of solution cost, when compared either to the classical Lagrangian Relaxation or to other metaheuristics. It also drastically reduced the computation times. Furthermore, the approach proved to be robust, always leading to good results independently of the metaheuristic parameters used.
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    Simulation-based optimization for steel stacking
    ( 2008) Rui Jorge Rei ; João Pedro Pedroso ; Mikio Kubo
    In many sectors of industry, manufacturers possess warehouses where finished goods are stored, awaiting to fulfill a client order. We present a situation where these items are characterized by release and due dates, i.e. warehouse arrival for storage and client delivery, respectively. The warehouse has a number of positions available, where items can be placed on top of each other, forming stacks. For item manipulation, there is a single a stacking crane, able to carry one item at a time. When in a given stack an item at the top is due at a date later than some item below it, it must be relocated to another stack, so that the item below can be delivered. In this problem the objective is to minimize the number of movements made by the crane.
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    Defining the regional innovation strategy for the year 2015: the case of the ITCE clusters in the North of Portugal
    ( 2008) Catarina Selada ; António Carrizo ; Luís Carneiro
    This paper describes the methodology and the definition of the regional innovation strategy, based on the Information Technology, Communications and Electronics (ITCE) clusters, for the North of Portugal under the project NORTINOV 2015, which was promoted by the commission for the coordination and regional development of the north of Portugal (CCDR-N) under the NORTINOV programme. Three strategic lines were proposed to achieve a regional innovation strategy for the ICTE cluster for the year 2015: the strategic line, in order to create conditions for the development of innovative clusters, the sustainability line, in order to facilitate the interaction with other clusters, and the structural line, in order to position the North region as a world-class region.