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Publications

2022

Ensemble Metropolis Light Transport

Authors
Bashford Rogers, T; Santos, LP; Marnerides, D; Debattista, K;

Publication
ACM TRANSACTIONS ON GRAPHICS

Abstract
This article proposes a Markov Chain Monte Carlo (MCMC) rendering algorithm based on a family of guided transition kernels. The kernels exploit properties of ensembles of light transport paths, which are distributed according to the lighting in the scene, and utilize this information to make informed decisions for guiding local path sampling. Critically, our approach does not require caching distributions in world space, saving time and memory, yet it is able to make guided sampling decisions based on whole paths. We show how this can be implemented efficiently by organizing the paths in each ensemble and designing transition kernels for MCMC rendering based on a carefully chosen subset of paths from the ensemble. This algorithm is easy to parallelize and leads to improvements in variance when rendering a variety of scenes.

2022

Literature Review on Artificial Intelligence Methods for Glaucoma Screening, Segmentation, and Classification

Authors
Camara, J; Neto, A; Pires, IM; Villasana, MV; Zdravevski, E; Cunha, A;

Publication
JOURNAL OF IMAGING

Abstract
Artificial intelligence techniques are now being applied in different medical solutions ranging from disease screening to activity recognition and computer-aided diagnosis. The combination of computer science methods and medical knowledge facilitates and improves the accuracy of the different processes and tools. Inspired by these advances, this paper performs a literature review focused on state-of-the-art glaucoma screening, segmentation, and classification based on images of the papilla and excavation using deep learning techniques. These techniques have been shown to have high sensitivity and specificity in glaucoma screening based on papilla and excavation images. The automatic segmentation of the contours of the optic disc and the excavation then allows the identification and assessment of the glaucomatous disease's progression. As a result, we verified whether deep learning techniques may be helpful in performing accurate and low-cost measurements related to glaucoma, which may promote patient empowerment and help medical doctors better monitor patients.

2022

Photo2Video: Semantic-Aware Deep Learning-Based Video Generation from Still Content

Authors
Viana, P; Andrade, MT; Carvalho, P; Vilaca, L; Teixeira, IN; Costa, T; Jonker, P;

Publication
JOURNAL OF IMAGING

Abstract
Applying machine learning (ML), and especially deep learning, to understand visual content is becoming common practice in many application areas. However, little attention has been given to its use within the multimedia creative domain. It is true that ML is already popular for content creation, but the progress achieved so far addresses essentially textual content or the identification and selection of specific types of content. A wealth of possibilities are yet to be explored by bringing the use of ML into the multimedia creative process, allowing the knowledge inferred by the former to influence automatically how new multimedia content is created. The work presented in this article provides contributions in three distinct ways towards this goal: firstly, it proposes a methodology to re-train popular neural network models in identifying new thematic concepts in static visual content and attaching meaningful annotations to the detected regions of interest; secondly, it presents varied visual digital effects and corresponding tools that can be automatically called upon to apply such effects in a previously analyzed photo; thirdly, it defines a complete automated creative workflow, from the acquisition of a photograph and corresponding contextual data, through the ML region-based annotation, to the automatic application of digital effects and generation of a semantically aware multimedia story driven by the previously derived situational and visual contextual data. Additionally, it presents a variant of this automated workflow by offering to the user the possibility of manipulating the automatic annotations in an assisted manner. The final aim is to transform a static digital photo into a short video clip, taking into account the information acquired. The final result strongly contrasts with current standard approaches of creating random movements, by implementing an intelligent content- and context-aware video.

2022

Acting emotions: physiological correlates of emotional valence and arousal dynamics in theatre

Authors
Aly, L; Bota, P; Godinho, L; Bernardes, G; Silva, H;

Publication
IMX 2022 - Proceedings of the 2022 ACM International Conference on Interactive Media Experiences

Abstract
Professional theatre actors are highly specialized in controlling their own expressive behaviour and non-verbal emotional expressiveness, so they are of particular interest in fields of study such as affective computing. We present Acting Emotions, an experimental protocol to investigate the physiological correlates of emotional valence and arousal within professional theatre actors. Ultimately, our protocol examines the physiological agreement of valence and arousal amongst several actors. Our main contribution lies in the open selection of the emotional set by the participants, based on a set of four categorical emotions, which are self-assessed at the end of each experiment. The experiment protocol was validated by analyzing the inter-rater agreement (> 0.261 arousal, > 0.560 valence), the continuous annotation trajectories, and comparing the box plots for different emotion categories. Results show that the participants successfully induced the expected emotion set to a significant statistical level of distinct valence and arousal distributions. © 2022 Owner/Author.

2022

Design and Experimental Tests of a Buoyancy Change Module for Autonomous Underwater Vehicles

Authors
Carneiro, JF; Pinto, JB; de Almeida, FG; Cruz, NA;

Publication
ACTUATORS

Abstract
Ocean exploration is of major importance for several reasons, including energy and mineral resource retrieval, sovereignty, and environmental concerns. The use of autonomous underwater vehicles (AUV) has thus been receiving increased attention from the scientific community. In this context, it has been shown that the use of buoyancy change modules (BCMs) can significantly improve the energy efficiency of an AUV. However, the literature regarding the detailed design of these modules is scarce. This paper contributes to this field by describing the development of an electromechanical buoyancy change module prototype to be incorporated into an existing AUV. A detailed description of the constraints and compromises existing in the design of the device components is presented. In addition, the mechanical design of the hull based on FEM simulations is described in detail. The prototype is experimentally tested in a shallow pool where its full functionality is shown. The paper also presents preliminary experimental values of the power consumption of the device and compares them with the ones provided by existing models in the literature.

2022

EPISA Platform: A Technical Infrastructure to Support Linked Data in Archival Management

Authors
Nunes, S; Silva, T; Martins, C; Peixoto, R;

Publication
Proceedings of the 26th International Conference on Theory and Practice of Digital Libraries - Workshops and Doctoral Consortium, Padua, Italy, September 20, 2022.

Abstract
In this paper we describe the EPISA Platform, a technical infrastructure designed and developed to support archival records management and access using linked data technologies. The EPISA Platform follows a client-server paradigm, with a central component, the EPISA Server, responsible for storage, reasoning, authorization, and search; and a frontend component, the EPISA ArchClient, responsible for user interaction. The EPISA Server uses Apache Jena Fuseki for storage and reasoning, and Apache Solr for search. The EPISA ArchClient is a web application implemented using PHP Laravel and standard web technologies. The platform follows a modular architecture, based on Docker containers. We describe the technical details of the platform and the main user interaction workflows, highlighting the abstractions developed to integrate linked data in the archival management process. The EPISA Platform has been successfully used to support research and development of linked data use in the archival domain in the context of the EPISA project. © 2022 Copyright for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0)

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