2023
Autores
Da Silveira, RIM; Torres Júnior, N; Teixeira, R; Simões, AC;
Publicação
Exacta
Abstract
2023
Autores
Lau, N; Reis, LP; Simões, D; Kasaei, M; Abreu, M; Silva, T; Resende, F;
Publicação
CoRR
Abstract
2023
Autores
Klimentova, X; Biro, P; Viana, A; Costa, V; Pedroso, JP;
Publicação
EUROPEAN JOURNAL OF OPERATIONAL RESEARCH
Abstract
Kidney exchange programs (KEPs) represent an additional possibility of transplant for patients suffering from end-stage kidney disease. If a patient has a willing living donor with whom the patient is not compatible, the pair recipient-donor can join a pool of incompatible pairs and, if compatibility between recipient and donor in two or more pairs exists, organs can be exchanged between them. The problem can be modelled as an integer program that in general aims at finding the pairs that should be selected for transplant such that maximum number of transplants is performed. In this paper, we consider that for each recipient there may exist a preference order over the organs that he/she can receive, since a recipient may be compatible with several donors but the level of compatibility with the recipient might vary for different donors. Under this setting, the aim is to find the maximum cardinality stable exchange, a solution where no blocking cycle exists, i.e., there is no cycle such that all recipients prefer the donor in that cycle rather than that in the exchange. For this purpose we propose four novel integer programming models based on the well-known edge and cycle formulations, and also on the position-indexed formulation. These formulations are adjusted for both finding stable and strongly stable exchanges under strict preferences and for the case when ties in preferences may exist. Further-more, we study a situation when the stability requirement can be relaxed by addressing the trade-off between maximum cardinality versus number of blocking cycles allowed in a solution. The effectiveness of the proposed models is assessed through extensive computational experiments on a wide set of in-stances. Results show that the cycle-edge and position-indexed formulations outperform the other two formulations. Another important practical outcome is that targeting strongly stable solutions has a much higher negative impact on the number of transplants (with an average reduction of up to 20% for the bigger instances), when compared to stable solutions.
2023
Autores
Gonçalves, G; Melo, M; Monteiro, P; Coelho, H; Bessa, M;
Publicação
COMPUTERS & GRAPHICS-UK
Abstract
Immersive Virtual Reality (IVR) provides a platform where the real world can be replicated to a point where users can act and react in the virtual world as they would in reality. However, rendering visual stimuli is computationally heavy. Thus, optimizations must be done to take advantage of computational systems by studying our perception of reality. This study investigated parameters related to light rendering (Global Illumination, Ambient Occlusion, Screen Space Reflections (SSR) and Direct Shadows) in real-time in a virtual replica of a real place using IVR. Participants experienced both virtual and real rooms with only one flashlight and changed the quality settings of the considered parameters so that their sense of reality would be the closest to the one they felt when they experienced the real room. Participants were given a budget to drive them to prioritize what parameters, and their level of quality, are the most important for their sense of reality. Results indicated that participants considered Global Illumination the most important factor, closely followed by Direct Shadows. Ambient Occlusion and Reflections (Screen Space Reflections) were the less prioritized parameters. We conclude that in a lighting setting where only dynamic lights are used, Global Illumination and Direct Shadows should be prioritized over SSR Reflections and Ambient Occlusion when computational power is limited.
2023
Autores
Salles, B; Cunha, J;
Publicação
2023 IEEE SYMPOSIUM ON VISUAL LANGUAGES AND HUMAN-CENTRIC COMPUTING, VL/HCC
Abstract
The architectural style of microservices has received much attention from both business and academia and converting a monolithic application into a microservice-based one has become a regular practice. However, companies struggle with migrating their existing monolithic applications to microservices and software engineers frequently face challenges due to a lack of awareness of alternative migration methodologies, making the migration process even harder. In this paper, we present a framework to help software engineers during the migration process by addressing gaps in understanding various migration tools and approaches, allowing for easy comparison between multiple options. Our tool combines multiple existing approaches into one platform, allowing a comprehensive visualization of migration proposals and comparing different options offered by already existing approaches.
2023
Autores
Toledo, R; Filho, JR; Marchisotti, G; Castro, H; Alves, C; Putnik, G;
Publicação
International Journal for Quality Research
Abstract
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