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Publications

2017

Fusion-Based Variational Image Dehazing

Authors
Galdran, A; Vazquez Corral, J; Pardo, D; Bertalmio, M;

Publication
IEEE SIGNAL PROCESSING LETTERS

Abstract
We propose a novel image-dehazing technique based on the minimization of two energy functionals and a fusion scheme to combine the output of both optimizations. The proposed fusion-based variational image-dehazing (FVID) method is a spatially varying image enhancement process that first minimizes a previously proposed variational formulation that maximizes contrast and saturation on the hazy input. The iterates produced by this minimization are kept, and a second energy that shrinks faster intensity values of well-contrasted regions is minimized, allowing to generate a set of difference-of-saturation (DiffSat) maps by observing the shrinking rate. The iterates produced in the first minimization are then fused with these DiffSat maps to produce a haze-free version of the degraded input. The FVID method does not rely on a physical model from which to estimate a depth map, nor it needs a training stage on a database of human-labeled examples. Experimental results on a wide set of hazy images demonstrate that FVID better preserves the image structure on nearby regions that are less affected by fog, and it is successfully compared with other current methods in the task of removing haze degradation from faraway regions.

2017

Data mining techniques for the grouping of certified wines from the sub-regions of the demarcated region of Vinho Verde [Técnicas de data mining para agrupamento dos vinhos certificados das sub-regiões da região demarcada dos Vinhos Verdes]

Authors
Souza Roza, R; Brazdil, P; Reis, JL; Cerdeira, A; Martins, P; Felgueiras, O;

Publication
Atas da Conferencia da Associacao Portuguesa de Sistemas de Informacao

Abstract
The combination of information obtained from data mining technique from physicochemical and organoleptic data analysis allowed similarities between the wines of the nine sub-regions in the Demarcated Region of Vinho Verde. Through clustering techniques, four clusters were identified, each characterized by its centroid. The measure of information gain, together with supervised rule-based learning, was used to find the differentiating characteristics. This study allowed the interconnection of the characteristics of the wines of these sub-regions, which can improve the decision making on the profiles of these same wines.

2017

A cable-driven robot for architectural constructions: a visual-guided approach for motion control and path-planning

Authors
Pinto, AM; Moreira, E; Lima, J; Sousa, JP; Costa, P;

Publication
AUTONOMOUS ROBOTS

Abstract
Cable-driven robots have received some attention by the scientific community and, recently, by the industry because they can transport hazardous materials with a high level of safeness which is often required by construction sites. In this context, this research presents an extension of a cable-driven robot called SPIDERobot, that was developed for automated construction of architectural projects. The proposed robot is formed by a rotating claw and a set of four cables, enabling four degrees of freedom. In addition, this paper proposes a new Vision-Guided Path-Planning System (V-GPP) that provides a visual interpretation of the scene: the position of the robot, the target and obstacles location; and optimizes the trajectory of the robot. Moreover, it determines a collision-free trajectory in 3D that takes into account the obstacles and the interaction of the cables with the scene. A set of experiments make possible to validate the contribution of V-GPP to the SPIDERobot while operating in realistic working conditions, as well as, to evaluate the interaction between the V-GPP and the motion controlling system. The results demonstrated that the proposed robot is able to construct architectural structures and to avoid collisions with obstacles in their working environment. The V-GPP system localizes the robot with a precision of 0.006 m, detects the targets and successfully generates a path that takes into account the displacement of cables. Therefore, the results demonstrate that the SPIDERobot can be scaled up to real working conditions.

2017

Detecting Journalistic Relevance on Social Media: A two-case study using automatic surrogate features

Authors
Figueira, A; Guimarães, N;

Publication
Proceedings of the 2017 IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining 2017, Sydney, Australia, July 31 - August 03, 2017

Abstract
The expansion of social networks has contributed to the propagation of information relevant to general audiences. However, this is small percentage compared to all the data shared in such online platforms, which also includes private/personal information, simple chat messages and the recent called ‘fake news’. In this paper, we make an exploratory analysis on two social networks to extract features that are indicators of relevant information in social network messages. Our goal is to build accurate machine learning models that are capable of detecting what is journalistically relevant. We conducted two experiments on CrowdFlower to build a solid ground truth for the models, by comparing the number of evaluations per post against the number of posts classified. The results show evidence that increasing the number of samples will result in a better performance on the relevancy classification task, even when relaxing in the number of evaluations per post. In addition, results show that there are significant correlations between the relevance of a post and its interest and whether is meaningfully for the majority of people. Finally, we achieve approximately 80% accuracy in the task of relevance detection using a small set of learning algorithms. © 2017 Copyright is held by the owner/author(s).

2017

Towards a middleware for mobile edge-cloud applications

Authors
Rodrigues, J; Marques, ERB; Lopes, LMB; Silva, FMA;

Publication
Proceedings of the 2nd Workshop on Middleware for Edge Clouds & Cloudlets, MECC@Middleware 2017, Las Vegas, NV, USA, December 11 - 15, 2017

Abstract
In the last decade, technological advances and improved manufacturing processes have significantly dropped the price tag of mobile devices such as smartphones and tablets whilst augmenting their storage and computational capabilities. Their ubiquity fostered research on mobile edge-clouds, formed by sets of such devices in close proximity, with the goal of mastering their global computational and storage resources. The development of crowdsourcing applications that take advantage of such edge-clouds is, however, hampered by the complexity of network formation and maintenance, the intrinsic instability of wireless links and the heterogeneity of the hardware and operating systems in the devices. In this paper we present a middleware to deal with this complexity, providing a building block upon which crowd-sourcing applications may be built.We motivate the development of the middleware through a discussion of real-world applications, and present the middleware's architecture along with the associated components and current development status. The middleware takes form as a Java API for Android devices that allows for the establishment of links using heterogeneous communication technologies (e.g., Wifi-Direct, Bluetooth), and the combination of these links to form a logical edge-cloud network. On top of this functionality, services for edge computation, storage, and streaming are also being developed. © 2017 Association for Computing Machinery.

2017

Energy Consumption Measurement of C/C++ Programs Using Clang Tooling

Authors
Santos, M; Saraiva, J; Porkoláb, Z; Krupp, D;

Publication
Proceedings of the Sixth Workshop on Software Quality Analysis, Monitoring, Improvement, and Applications, Belgrade, Serbia, September 11-13, 2017.

Abstract
The green computing has an important role in today's software technology. Either speaking about small IoT devices or large cloud servers, there is a generic requirement of minimizing energy consumption. For this purpose, we usually first have to identify which parts of the system is responsible for the critical energy peaks. In this paper we suggest a new method to measure the energy consumption based on Low Level Virtual Machine (LLVM)/Clang tooling. The method has been tested on 2 open source systems and the output is visualized via the well-known Kcachegrind tool. © Copyright 2017 by the paper's authors.

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