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Repositório IC-Online

Institution's Scientific Repository

 

IC-Online, the Institutional Repository of Scientific Information of the Polytechnic of Leiria (IPLeiria), is part of the RCAAP Project (Open Access Scientific Repositories of Portugal). Its main objectives are to organise, preserve and disseminate the scientific production of the Polytechnic of Leiria (IPLeiria), helping to increase the visibility and impact of the institution's scientific publications.

The IC-Online Repository includes various types of digital documents, such as articles from national and international scientific journals, papers from congresses and conferences, master's dissertations and doctoral theses, among others.

Email repositorio@ipleiria.pt

Recent Submissions

Asymptotic Analysis of the Method of Fundamental Solutions for Acoustic Wave Propagation
Publication . Valtchev, Svilen S.
The asymptotic behavior of the Method of Fundamental Solutions (MFS) is analyzed, for the numerical solution of acoustic wave propagation problems in 2D and 3D bounded domains. As a consequence, a meshfree method, based on superposition of plane acoustic waves, referred to as the Plane Waves Method (PWM), is developed. Numerical examples are included in order to illustrate the relation between the two methods and the accuracy of the PWM.
2010-09-30Journal article Restricted access Show more
Maximin spreading algorithm
Publication . Pires, E. J. Solteiro; Mendes, Luís; Lopes, António M.; Oliveira, P. B. de Moura; Machado, J. A. Tenreiro; Vaz, João; Rosário, Maria J.
This paper presents a genetic algorithm to optimize uni-objective problems with an infinite number of optimal solutions. The algorithm uses the maximin concept and e-dominance to promote diversity over the admissible space. The proposed algorithm is tested with two well-known functions. The practical results of the algorithm are in good agreement with the optimal solutions of these functions. Moreover, the proposed optimization method is also applied in two practical real-world engineering optimization problems, namely, in radio frequency circuit design and in kinematic optimization of a parallel robot. In all the cases, the algorithm draws a set of optimal solutions. This means that each problem can be solved in several different ways, all with the same maximum performance.
2010-07Conference paper Restricted access Show more
A Hybrid Scatter Search algorithm to assign terminals to concentrators
Publication . Bernardino, Eugénia Moreira; Bernardino, Anabela Moreira; Sánchez-Pérez, Juan Manuel; Gómez-Pulido, Juan Antonio; Vega-Rodríguez, Miguel Angel
The last few years have seen a significant growth in communication networks. With the growth of data traffic, network operators seek network-engineering tools to extract the maximum benefits out of the existing infrastructure. This has suggested a number of new optimisation problems, most of them in the field of combinatorial optimisation. We address here the Terminal Assignment problem. The main objective is to assign a collection of terminals to a collection of concentrators. In this paper, we propose a Hybrid Scatter Search (HSS) algorithm to assign terminals to concentrators. Coupled with the Scatter Search algorithm we use a Tabu Search algorithm to locate the global minimum. We show that HSS is able to achieve feasible solutions to Terminal Assignment instances, improving the results obtained by previous approaches.
2010-07Conference paper Restricted access Show more
Poly(ɛ-caprolactone) and Polyethylene Glycol Diacrylate-based Scaffolds for TMJ Bioengineered Disc Implants
Publication . Francisco, Luís; Moura, Carla; Viana, Tânia; Ângelo, David; Morouço, Pedro; Alves, Nuno
The temporomandibular joint (TMJ), articulation between the mandibular condyle and the temporal bone, is divided into two compartments (superior and inferior) by a fibrocartilaginous disc. The TMJ disc consists on an avascular and non-innervated tissue, with viscoelastic behavior. Mechanically, the TMJ disc experiences tensile, compressive and shear forces. TMJ disc displacement or degeneration could lead to severe intra-articular temporomandibular joint disorders (TMD). Despite the large number of current therapies/treatments, there is limited treatment options for severe intra-articular TMD. A strategy to solve this problem could be the use of an interposal material to substitute the damaged TMJ disc, which will gradually degrade and give rise to new tissue. In this work three options were used and tested, one using a thermoplastic material, poly(ε-caprolactone) (PCL), another using an photopolymerized hydrogel, polyethylene glycol diacrilate (PEGDA) and the third using the combination of the two materials. Obtained results demonstrated that that the combination of different materials could represent a significant advantage in the TMJ disc TE and in the cartilage TE in general.
2017Journal article Open access Show more
An empirical comparison of Canonical Correspondence Analysis and STATICO in the identification of spatio-temporal ecological relationships
Publication . Mendes, Susana; Fernández-Gómez, M. José; Pereira, Mário Jorge; Azeiteiro, Ulisses Miranda; Galindo-Villardón, M. Purificación
The wide-ranging and rapidly evolving nature of ecological studies mean that it is not possible to cover all existing and emerging techniques for analyzing multivariate data. However, two important methods enticed many followers: the Canonical Correspondence Analysis (CCA) and the STATICO analysis. Despite the particular characteristics of each, they have similarities and differences, which when analyzed properly, can, together, provide important complementary results to those that are usually exploited by researchers. If on one hand, the use of CCA is completely generalized and implemented, solving many problems formulated by ecologists, on the other hand, this method has some weaknesses mainly caused by the imposition of the number of variables that is required to be applied (much higher in comparison with samples). Also, the STATICO method has no such restrictions, but requires that the number of variables (species or environment) is the same in each time or space.Yet, the STATICO method presents information that can be more detailed since it allows visualizing the variability within groups (either in time or space). In this study, the data needed for implementing these methods are sketched, as well as the comparison is made showing the advantages and disadvantages of each method. The treated ecological data are a sequence of pairs of ecological tables, where species abundances and environmental variables are measured at different, specified locations, over the course of time.
2012-05Journal article Restricted access Show more