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INESC-ID

NonprofitLisbon, Portugal
About: INESC-ID is a nonprofit organization based out in Lisbon, Portugal. It is known for research contribution in the topics: Field-programmable gate array & Control theory. The organization has 932 authors who have published 2618 publications receiving 37658 citations.


Papers
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Journal ArticleDOI
TL;DR: Two different tools, both based on Boolean satisfiability (SAT), for solving Linux upgradeability problems are described, both of which can provide optimal solutions for many of the instances, but a few challenges remain.
Abstract: Managing the software complexity of package-based systems can be regarded as one of the main challenges in software architectures. Upgrades are required on a short time basis and systems are expected to be reliable and consistent after that. For each package in the system, a set of dependencies and a set of conflicts have to be taken into account. Although this problem is computationally hard to solve, efficient tools are required. In the best scenario, the solutions provided should also be optimal in order to better fulfill users requirements and expectations. This paper describes two different tools, both based on Boolean satisfiability (SAT), for solving Linux upgradeability problems. The problem instances used in the evaluation of these tools were mainly obtained from real environments, and are subject to two different lexicographic optimization criteria. The developed tools can provide optimal solutions for many of the instances, but a few challenges remain. Moreover, it is our understanding that this problem has many similarities with other configuration problems, and therefore the same techniques can be used in other domains.

21 citations

Proceedings ArticleDOI
01 Feb 2016
TL;DR: In this article, a droop-passivity based controller for the grid-connected single-phase voltage-source inverter (SPVSI) is proposed, in which an effective harmonic compensation scheme along with a proper active and reactive power sharing algorithm are performed by a well-designed reference waveform generation process.
Abstract: A comprehensive dynamic model based on Direct-Quadrature (DQ) rotating frame is proposed in this paper that is used along with a capability curve (CC) based on the active and reactive power to control a grid-connected single-phase voltage-source inverter (SPVSI). With the proposed dynamic model, a droop-passivity based controller can be designed for the grid-connected inverter in the presence of nonlinear loads. Stability analysis of the proposed control technique is also discussed in the paper as well as design principles. Moreover, an accurate performance area of SPVSI active and reactive power in dynamic transitions is achieved using the CC. Furthermore, an effective harmonic compensation scheme along with a proper active and reactive power sharing algorithm are performed by a well-designed reference waveform generation process. Performance of the grid-connected SPVSI, under the proposed controller, is thoroughly evaluated in the Matlab/Simulink environment.

20 citations

Journal ArticleDOI
TL;DR: This work proposes the use of a fault-tolerant converter based on the quasi-Z-source inverter (qZSI), which results in three-phase balanced AC currents with reduced total harmonic distortion even in faulty condition.
Abstract: The requirement of three-phase inverters with high reliability capability is considered important in several applications. Most of the adopted fault-tolerant solutions use classical three-phase voltage source inverters (VSI) with redundant controlled power devices or modified control strategies for acceptably degraded performance in the event of a failure yielding the loss of devices. This work proposes the use of a fault-tolerant converter based on the quasi-Z-source inverter (qZSI). This inverter presents important features such as boost capability and not requires dead time circuits. These features associated to the proposed topology results in a converter with high reliability and fault-tolerant capability. The proposed topology is designed to allow the reconfiguration of the converter after a power switch failure, using only two legs in the faulty mode. Additionally, this topology avoids extra inductors, capacitors and active power switches for the fault-tolerant condition. A current controller associated to a vectorial voltage modulator is used to control the proposed topology, which results in three-phase balanced AC currents with reduced total harmonic distortion even in faulty condition. The performance of this solution is confirmed through experimental results obtained from a laboratory prototype.

20 citations

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a new topology for a DC-DC converter with bipolar output and high voltage gain, which was designed with the aim to use only one active power switch.
Abstract: This paper introduces a new topology for a DC-DC converter with bipolar output and high voltage gain. The topology was designed with the aim to use only one active power switch. Besides the bipolar multiport output and high voltage gain this converter has another important feature, namely, it has a continuous input current. Due to the self-balancing bipolar outputs, the proposed topology is suitable for bipolar DC microgrids. Indeed, the topology balancing capability can achieve the two symmetrical voltage poles of bipolar DC microgrids. Furthermore, it is possible to create a midpoint in the output of the converter that can be directly connected to the ground of the DC power supply, avoiding common-mode leakage currents in critical applications such as transformerless grid-connect PV systems. The operating principle of the proposed topology will be supported by mathematical analysis. To validate and verify the characteristics of the presented topology, several experimental results are shown.

20 citations

Book ChapterDOI
01 Jan 2019
TL;DR: This paper created four distinct classifiers, trained using a supervised approach, each one considering a group of features extracted from four different sources: user name and screen name, user description, content of the tweets, and profile picture, and a final classifier that combines the prediction of each one of the four previous individual classifiers achieves the best performance.
Abstract: Twitter provides a simple way for users to express feelings, ideas and opinions, makes the user generated content and associated metadata, available to the community, and provides easy-to-use web and application programming interfaces to access data. The user profile information is important for many studies, but essential information, such as gender and age, is not provided when accessing a Twitter account. However, clues about the user profile, such as the age and gender, behaviors, and preferences, can be extracted from other content provided by the user. The main focus of this paper is to infer the gender of the user from unstructured information, including the username, screen name, description and picture, or by the user generated content. We have performed experiments using an English labelled dataset containing 6.5 M tweets from 65 K users, and a Portuguese labelled dataset containing 5.8 M tweets from 58 K users. We have created four distinct classifiers, trained using a supervised approach, each one considering a group of features extracted from four different sources: user name and screen name, user description, content of the tweets, and profile picture. Features related with the activity, such as number of following and number of followers, were discarded, since these features were found not indicative of gender. A final classifier that combines the prediction of each one of the four previous individual classifiers achieves the best performance, corresponding to 93.2% accuracy for English and 96.9% accuracy for Portuguese data.

20 citations


Authors

Showing all 967 results

NameH-indexPapersCitations
João Carvalho126127877017
Jaime G. Carbonell7249631267
Chris Dyer7124032739
Joao P. S. Catalao68103919348
Muhammad Bilal6372014720
Alan W. Black6141319215
João Paulo Teixeira6063619663
Bhiksha Raj5135913064
Joao Marques-Silva482899374
Paulo Flores483217617
Ana Paiva474729626
Miadreza Shafie-khah474508086
Susana Cardoso444007068
Mark J. Bentum422268347
Joaquim Jorge412906366
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202311
202252
202196
2020131
2019133
2018126