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Publications

Publications by Rui Pedro Rodrigues

2013

Circle covering using medial axis

Authors
Rocha, P; Rodrigues, R; Toledo, FMB; Gomes, AM;

Publication
IFAC Proceedings Volumes (IFAC-PapersOnline)

Abstract
A good representation of a simple polygon, with a desired degree of approximation and complexity, is critical in many applications. This paper presents a method to achieve a complete Circle Covering Representation of a simple polygon, through a topological skeleton, the Medial Axis. The aim is to produce an efficient circle representation of irregular pieces, while considering the approximation error and the resulting complexity, i.e. the number of circles. This will help to address limitations of current approaches to some problems, such as Irregular Placement problems, which will, in turn, provide a positive economic and environmental impact where similar problems arise. © 2013 IFAC.

2014

A physics simulation tool for the container loading problem

Authors
Ramos, AG; Jacob, J; Justo, J; Oliveira, JF; Rodrigues, R; Gomes, AM;

Publication
26th European Modeling and Simulation Symposium, EMSS 2014

Abstract
In the Container Loading Problem literature, the cargo dynamic stability constraint has been evaluated by the percentage of boxes with insufficient lateral support. This metric has been used as a proxy for the real-world dynamic stability constraint and has conditioned the algorithms developed for this problem. It has the advantage of not being expensive from a computation perspective. However, guaranteeing that at least three sides of a box are in contact with another box or with the container wall does not necessarily ensure stability during transportation. In this paper we propose a physics simulation tool based on a physics engine that will be used in the evaluation of the dynamic stability constraint. We compare the results of our physics simulation tool with the state-of-the-art simulation engineering software Abaqus Unified FEA, and conclude that our tool is a promising alternative.

2017

Adaptivity and safety in location-based games

Authors
Jacob, J; Nobrega, R; Coelho, A; Rodrigues, R;

Publication
9th International Conference on Virtual Worlds and Games for Serious Applications, VS-Games 2017, Athens, Greece, September 6-8, 2017

Abstract
Location-based games require, among other things, obtaining or computing information regarding the players' physical activity and real-world context. Additionally, ensuring that the players are assigned challenges that are adequate and safe for the current context (both physical and spatial) is also important, as it can improve both the gaming experience and the outcomes of the exercise. However, the impact adaptivity has in the specific case of location-based exergames still has not been researched in depth. In this paper, we present a location-based exergame capable of adapting its mechanics to the current context. © 2017 IEEE.

2016

Video Annotation for Immersive Journalism using Masking Techniques

Authors
Meira, J; Marques, J; Jacob, J; Nobrega, R; Rodrigues, R; Coelho, A; Augusto de Sousa, AA;

Publication
2016 23RD PORTUGUESE MEETING ON COMPUTER GRAPHICS AND INTERACTION (EPCGI)

Abstract
This paper proposes an interactive annotation technique for 360 degrees videos that allows the use of traditional video editing techniques to add content to immersive videos. Using the case study of immersive journalism the main objective is to diminish the entry barrier for annotating 360 degrees video pieces, by providing a different annotation paradigm and a set of tools for annotation. The spread of virtual reality systems and immersive content has been growing substantially due to technological progress and cost reductions in equipment and software. From all the technologies employed in virtual reality systems, 360 degrees video is one that currently presents unique conditions to be widely used by various industries -especially for communication purposes. From the various areas that can benefit from the usage of virtual reality systems, the communication field is one that requires innovation in the way that narratives are built, especially in virtual reality systems. In the case of immersive journalism, 360 degrees video technology is currently one of the most used mediums by several media outlets. This kind of news content, whose innovative role should be highlighted, is still being studied in the field of journalism, needing a clearly defined set of rules and good practises. In order to improve the introduction of virtual elements in the 360 degrees videos this paper proposes a set of annotation paradigms for 1) Media information display and 2) Narrative and attention focusing. In this paper we present a list of possible techniques that solve the problem of immersive annotation, as well as a description of a prototype that was developed to test these concepts. The prototype implements an annotation technique based on masked videos and the extension of standard subtitle file formats. Finally a fast-track user study was developed to evaluate the acceptance of the visualisation techniques and to refine the set of tools.

2014

Circle covering representation for nesting problems with continuous rotations

Authors
Rocha, P; Rodrigues, R; Gomes, AM; Toledo, FMB; Andretta, M;

Publication
IFAC Proceedings Volumes (IFAC-PapersOnline)

Abstract
This paper analyses distinct methods to represent a polygon through circle covering, which satisfy specific requirements, that impact primarily the feasibility and the quality of the layout of final solution. The trade-off between the quality of the polygonal representation and its derived number of circles is also discussed, showing the impact on the resolution of the problem, in terms of computational efficiency. The approach used to tackle the Nesting problem in strip packing uses a Non-Linear Programming model. Addressing these problems allows to tackle real world problems with continuous rotations. © IFAC.

2015

Two-Phase Approach to the Nesting problem with continuous rotations

Authors
Rocha, P; Rodrigues, R; Miguel Gomes, AM; Toledo, FMB; Andretta, M;

Publication
IFAC PAPERSONLINE

Abstract
This paper presents an approaches. that assists in producing highly compacted Nesting layouts with irregular pieces using free rotations. This approach consists in the selection and compaction of big pieces in a first phase, while in a second phase, places the remaining small pieces between the big pieces, compacting all of them. The effect of several parameters are analyzed, such as minimum length to be achieved in the first phase, attraction of the pieces to the edges of the container, attraction between each pair of pieces, among others. This approach can provide good compaction results, while improving computational cost in some cases, which cart allow to tackle real world problems more effectively mkt efficiently.

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