CIIC - Publicações em Atas de Conferências com Peer Review
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- Discrete Compound Tests and Dorfman’s Methodology in the Presence of MisclassificationPublication . Santos, Rui; Martins, João Paulo; Felgueiras, MiguelCompound tests can be used to save resources for classification or estimation purposes in clinical trials and quality control. Nevertheless, the methodologies that are usually applied are restricted to qualitative group tests. Moreover, when quantitative compound tests are applied the problem is to ascertain whether the amount of some substance of any individual in the group is greater or lower than a prefixed threshold. An overview of the applications of the discrete compound tests highlights the advantages (to save resources) and disadvantages (higher probability of misclassification), and suggests criteria to assess the suitability of applying Dorfman’s methodology.
- Evolution of Artificial Terrains for Video Games Based on AccessibilityPublication . Frade, Miguel; Vega, Francisco Fernandez de; Cotta, CarlosDiverse methods have been developed to generate terrains under constraints to control terrain features, but most of them use strict restrictions. However, there are situations were more flexible restrictions are sufficient, such as ensuring that terrains have enough accessible area, which is an important trait for video games. The Genetic Terrain Program technique, based on genetic programming, was used to automatically evolve Terrain Programs (TPs - which are able to generate terrains procedurally) for the desired accessibility parameters. Results showed that the accessibility parameters have negligible influence on the evolutionary system and that the terminal set has a major role on the terrain look. TPs produced this way are already being used on Chapas video game.
- Exploring Pareto scale mixturesPublication . Felgueiras, Miguel; Santos, RuiPareto 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.
- Hybrid population-based incremental learning to assign terminals to concentratorsPublication . Bernardino, Eugénia Moreira; Bernardino, Anabela Moreira; Sánchez-Pérez, Juan Manuel; Gómez-Pulido, Juan Antonio; Vega-Rodríguez, Miguel AngelIn the last decade, we have seen a significant growth in communication networks. In centralised communication networks, a central computer serves several terminals or workstations. In large networks, some concentrators are used to increase the network efficiency. A collection of terminals is connected to a concentrator and each concentrator is connected to the central computer. In this paper we propose a Hybrid Population-based Incremental Learning (HPBIL) to assign terminals to concentrators. We use this algorithm to determine the minimum cost to form a network by connecting a given collection of terminals to a given collection of concentrators. We show that HPBIL is able to achieve good solutions, improving the results obtained by previous approaches.
- A Hybrid Scatter Search algorithm to assign terminals to concentratorsPublication . Bernardino, Eugénia Moreira; Bernardino, Anabela Moreira; Sánchez-Pérez, Juan Manuel; Gómez-Pulido, Juan Antonio; Vega-Rodríguez, Miguel AngelThe 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.
- Pseudo-convex mixturesPublication . Felgueiras, Miguel; Martins, João; Santos, RuiAllowing weights w∈]−1;1]\{0}, pseudo-convex mixtures increase usual mixtures flexibility. The finite mixtures with negative components are investigated for distribution families closed under minimization. The main purpose is to define these mixtures and to study their properties.
- Quality Management: Concepts and Approaches for Software ProjectsPublication . Gonçalves, Dulce; Varajão, João; Martinho, Ricardo; Cruz, José BulasIn a world of growing competitiveness, “quality” is a main subject. On recent years, there has been a trend towards the improvement of software projects’ quality. This means improving not only the final software products, but especially the quality of leadership and of project management. It is now recognized that the quality of software products and services can be improved if quality management is accomplished according to the unique characteristics and complexity of each project. In this paper we present the main concepts of quality management, as also some approaches of software quality assurance. We then gather them around and, using the Deming’s philosophy, present the Total Quality Management paradigm. We also discuss the rules and standards of Quality Management Systems (ISO 9000 and CMMI), and identify some misfits regarding the specific context of software development.
- Solving the ring arc-loading problem using a hybrid scatter search algorithmPublication . Bernardino, Anabela Moreira; Bernardino, Eugénia Moreira; Sánchez-Pérez, Juan Manuel; Gómez-Pulido, Juan Antonio; Vega-Rodríguez, Miguel AngelResilient Packet Ring (RPR) is a standard that uses Ethernet switching and a dual counter-rotating ring topology to provide SONET-like network resiliency and optimised bandwidth usage, while it delivers multipoint Ethernet/IP services. An important optimisation problem arising in this context is the Weighted Ring Arc Loading Problem (WRALP). That is the design of a direct path for each request in a communication network, in such a way that high load on the arcs will be avoided, where an arc is an edge endowed with a direction. The load of an arc is defined as the total weight of those requests routed through the arc in its direction. WRALP ask for a routing scheme such that the maximum load on the arcs will be minimum. In this paper we study the loading problem without demand splitting and for solving it we propose a Hybrid Scatter Search (HSS) algorithm. 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 WRALP instances, improving the results obtained by previous approaches.