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Publications

2019

Improving and modeling the performance of a Publish-Subscribe message broker

Authors
Rocha, R; Maia, C; Ferreira, LL; Varga, P;

Publication
45TH ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY (IECON 2019)

Abstract
The Event Handler - a publish-subscribe broker implemented over REST/HTTP(S) - is an auxiliary system of the Arrowhead framework for IoT applications. During this work we found that the existing implementation of the Event Handler suffers from serious performance issues. This paper describes the reengineering effort that ultimately enabled it to reach much more acceptable levels of performance, by using appropriate software configurations and design patterns. Additionally, we also illustrate how this enhanced version of the Event Handler can be modeled using Petri nets, to depict the performance impact of different thread pool configurations and CPU core availability. The main objective of this modeling process is to enable the estimation of the system's performance to guarantee the required quality of service.

2019

Flexible on Demand Transport Services (FDTS): The future of mobility systems

Authors
Barreto, L; Amaral, A; Baltazar, S;

Publication
2019 IEEE INTERNATIONAL CONFERENCE ON ENGINEERING, TECHNOLOGY AND INNOVATION (ICE/ITMC)

Abstract
Mobility is an essential part of modern society and of the actual panorama of mobility and accessibility, including Public Transportation Systems (PTS), needs to be rethink and adapted, regarding the social and technological evolutions, enhancing a healthier, environmentally sustainable, economic viable and equitable transportation for all the population. This paper describes the actual mobility attributes, through mentioning diverse case studies, and technological features/requirements towards presenting a solution to achieve the redefinition of mobility systems, i.e. allowing to enhance integrated mobility options, from the Public Transport (PT) modes through the soft modes enclosure, supported by a technological system that could manage and support the efficient use of such mobility options - that is designated as Flexible on Demand Transport Services (FDTS). The involvement and commitment of all the stakeholders in the mobility process as well as the municipal support, and the policy makers in general is essential to fully adopt the mobility framework dynamics and implement the future mobility of the intermodal system and of the MaaS integration.

2019

Localization Based on Natural Features Detector for Steep Slope Vineyards

Authors
Mendes, JM; dos Santos, FN; Ferraz, NA; do Couto, PM; dos Santos, RM;

Publication
JOURNAL OF INTELLIGENT & ROBOTIC SYSTEMS

Abstract
Placing ground robots to work in steep slope vineyards is a complex challenge. The Global Positioning System (GPS) signal is not always available and accurate. A reliable localization approach to detect natural features for this environment is required. This paper presents an improved version of a visual detector for Vineyards Trunks and Masts (ViTruDe) and, a robot able to cope pruning actions in steep slope vineyards (AgRob V16). In addition, it presents an augmented data-set for other localization and mapping algorithm benchmarks. ViTruDe accuracy is higher than 95% under our experiments. Under a simulated runtime test, the accuracy lies between 27% - 96% depending on ViTrude parametrization. This approach can feed a localization system to solve a GPS signal absence. The ViTruDe detector also considers economic constraints and allows to develop cost-effective robots. The augmented training and datasets are publicly available for future research work.

2019

Real-Time Scheduling of Demand Response Options Considering the Volatility of Wind Power Generation

Authors
Talari, S; Shafie Khah, M; Chen, Y; Wei, W; Gaspar, PD; Catalao, JP;

Publication
IEEE TRANSACTIONS ON SUSTAINABLE ENERGY

Abstract
In this paper, a new methodology to unleash the potential of demand response (DR) in real-time is presented. Customers may tend to apply their DR potential in the real-time market in addition to their scheduled potential in the day-ahead stage. Thus, the proposed method facilitates balancing the real-time market via DR aggregators. It can be vital, once the stochastic variables of the network such as production of wind power generators do not follow the forecasted production in real-time and have some distortions. Two-stage stochastic programming is employed to schedule some DR options in both day-ahead and real-time markets. DR options in real-time are scheduled based on possible scenarios that reflect the behaviors of wind power generation and are generated through Monte-Carlo simulation method. The merits of the method are demonstrated in a 6-bus case study and in the IEEE RTS-96, which shows a notable reduction in total operation cost.

2019

Exploring Social Validation on A Collaborative Curation Platform

Authors
Pimentel, AP; Schneider, D; Oliveira, L; de Souza, J; Correia, A; Motta, C;

Publication
PROCEEDINGS OF THE 2019 IEEE 23RD INTERNATIONAL CONFERENCE ON COMPUTER SUPPORTED COOPERATIVE WORK IN DESIGN (CSCWD)

Abstract
In recent years, social curation technology has been successfully promoted as a means of addressing the problem of involving citizens with news content. Sites like Facebook, Reddit and Storify, just to name a few, allow their users to discuss, comment, share, identify and review news content from various sources. A key goal of this paper is to analyze the process of social validation in the context of Acropolis, a social computing platform that allows citizens to build and share their own narratives about complex or long-term news stories. The sense of social validation determines an increase in self-esteem, self-confidence, and instant happiness, when conveniently engendered in virtual environments.

2019

FUNCTIONAL METAMATERIALS FOR OPTICAL SENSING OF HYDROGEN

Authors
Guerreiro, A; Apolinario, A; Lopes, A; Hierro Rodriguez, A; Aguilar, G; Baptista, JM; Silva, NA; Frazao, O; Quiterio, P; Jorge, P; Rodrigues, P; Moraes, SS; Silva, S; Ferreira, TD; Santos, JL; Araujo, JP;

Publication
FOURTH INTERNATIONAL CONFERENCE ON APPLICATIONS OF OPTICS AND PHOTONICS

Abstract
We present the design, fabrication and optical characterization of functional metamaterials for optical sensing of Hydrogen based on inexpensive self-assembly processes of metallic nanowires integrated in nanoporous alumina templates([37-42]). The optical properties of these materials strongly depend on the environmental concentration or partial pressure of hydrogen and can be used to develop fully optical sensors that reduce the danger of explosion. Optical metamaterials are artificial media, usually combining metallic and dielectric sub-wavelength structures, that exhibit optical properties that cannot be found in naturally occurring materials. Among these, functional metamaterials offer the added possibility of altering or controlling these properties externally after fabrication, in our case by contact with a hydrogen rich atmosphere. This dependency can be used to design([43-45]) and develop optical sensors that respond to this gas or to chemical compounds that contain or release hydrogen. In this paper we present some designs for hydrogen functional metamaterials and discuss the main parameters relevant in the optimization of their response.

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