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Maximizing the placement of congruent polyhedrain a parallelepiped container
Publication . Gaspar, M. Belbut; Martins-Ferreira, N.
Given multiple identical polyhedral objects and a parallelepiped container, how should one place the objects so
that the largest number fits inside the container? This simple question is important in many applications, yet the answer is elusive. In fact, we know of no published solution for this very general formulation. Still, in many circumstances, further restrictions apply, resulting in a large number of variations requiring different algorithmic strategies. In this presentation we will further formalize the problem, present some of its many variations, and in particular one that applies to the stereolithographic rapid prototyping technology.
Preface of the "Symposium on integrated computational tools for advanced manufacturing"
Publication . Alves, Nuno
The Symposium on Integrated Computational Tools for Advanced Manufacturing, held within 10th International
Conference of Numerical Analysis and Applied Mathematics, Kos, Greece, from September 19 to 25, 2012, is a
relevant forum for the scientific exchange of multidisciplinary issues related to integrated computational tools for advanced manufacturing. The symposium contains eight reviewed papers, covering important research topics, such as multidisciplinary optimization, numerical modelling, computer-aided design, computer-aided engineering and additive manufacturing technologies.
Exploring Pareto scale mixtures
Publication . Felgueiras, Miguel; Santos, Rui
Pareto scale mixtures can be used to obtain distributions with heavier tails. An explanation of this model properties is provided, together with a discussion about the parameters estimation. Finally, a real data application is presented, consisting in the larger earthquakes seismic moment modeling.
Performance Assessment of Turbo-roundabouts in Corridors
Publication . Silva, Ana Bastos; Mariano, Pedro; Silva, João Pedro
There is a widespread agreement in the scientific community that the transformation of a conventional multi-lane roundabout into a turbo-roundabout results in a significant increase of road safety levels. However there is no consensus regarding its effect in terms of capacity, as there are some authors that point towards a small reduction in capacity, namely in the major roads entries. The concept of turbo-roundabout is quite recent and therefore there are only a few studies of its performance, in particular, when applied in a network or in a corridor. In this context, this paper focuses on the evaluation of the performance of the turbo-roundabout solution, when applied in corridor, compared to a normal double-lane roundabout. The analysis was based on two key components: capacity and pollutant emissions. The work was supported by microsimulation techniques using the AIMSUN software, based on a real case study calibrated and validated for this purpose. It was possible to conclude that the turbo-roundabout performance is strongly influenced by the traffic load of the network, severely losing its performance in oversaturation conditions. The performance of the solution was also particularly sensitive to the traffic directional distribution, both in the entries as well as in the corridor. In global terms, it was found that the results for the environmental indicators follow the progress of the capacity indicators.
Optimalmould-part I: Multi-objective optimization to moulds design for injection of polymers
Publication . Ramos, Carina; Carreira, P.; Bártolo, Paulo; Alves, Nuno
The problem of mould design optimisation for polymer injection is a key issue for both mouldmaking and
polymer injection industries. Several computational tools have proposed to address this problem. However they do not cover all aspects related to both mould design and injection moulding process, usually requiring the geometrical configuration of the initial mould solution. This paper presents a novel multi-objective optimisation tool, integrating CAD and CAE tools to optimise mould design parameters and injection moulding process parameters. No initial geometric definition of the mould is required. An industrial case study was considered to validate the proposed approach and the performance of several optimisation algorithms evaluated.