Institution
INESC-ID
Nonprofit•Lisbon, 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.
Topics: Field-programmable gate array, Control theory, Adaptive control, Model predictive control, Machine translation
Papers published on a yearly basis
Papers
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TL;DR: This study proposes a new structure for the three-phase DC−AC conversion stage for a grid-connected PV system that consists of two four-leg two-level voltage source inverters that are connected to two PV generators.
Abstract: Voltage source inverters (VSIs) are power converters that are considered essential in grid connected photovoltaic (PV) generators. There are several types of topologies for these converters. However, from the point of view of high-quality AC output voltage, multilevel inverters are considered the most adequate. Under this context, this study proposes a new structure for the three-phase DC−AC conversion stage for a grid-connected PV system. It consists of two four-leg two-level voltage source inverters that are connected to two PV generators. These inverters are associated with two Scott transformers. The secondary windings of the transformer are connected in a way that allows a series connection. Due to this, a multilevel operation will be achieved. The performance of the proposed power conditioning system will be verified through simulation and experimental results.
16 citations
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TL;DR: Investigation of the importance of representing a wide range of economic and physical sources of uncertainty in the modelling of the electricity market, both for investment decision making and descriptive market modelling demonstrates the difference between a deterministic and stochastic solution increases non-linearly when uncertainties across multiple inputs are combined.
15 citations
19 Sep 2012
TL;DR: The main linguistic criteria that were adopted in the classification of ViPEr, the Lexicon-Grammar of European Portuguese verbs, a database with distributional, syntactic and semantic properties of the most frequently occurring verbs are presented.
Abstract: This paper presents the current state of ViPEr, the Lexicon-Grammar of European Portuguese verbs, a database with distributional, syntactic and semantic properties of the most frequently occurring verbs The classification follows the theoretical framework of the Lexicon-Grammar The paper presents the main linguistic criteria that were adopted in the classification of 5052 frequently occurring verbs, which yield 6,059 different constructions or word senses The paper concludes with some preliminary results on the application of ViPEr to texts and plans for future work 1 Introduction The use of reliable, large-coverage language resources is key to the performance of many Natural Language Processing (NLP) systems To our knowledge, while some syntactic descriptions of European Portuguese verbs exist, most have not been made publicly available to the NLP community or just consist in human-oriented dictionaries, not having been built for computational processing (FERNANDES 2008, BORBA 1991; BUSSE 1994) On the other hand, partial linguistic studies have produced throughout the last three decades, with major efforts in the late 90s (OLIVEIRA 1981; NASCIMENTO 1997; RODRIGUES 1997), but little, if any, use was made by the NLP community of such data, and very little effort has been addressed to validate or test those, mostly introspective-sourced, and theoretically-oriented, linguistic descriptions A recent attempt in that direction is that of GOMES (2011), that highlighted the difficulties of the task For this project, a practical approach to the lexicon was adopted For many NLP tasks, but specially for any task where a fine-grained semantic distinction in required of ambiguous lexical forms, being able to identify the meaning of the verb (and of the surrounding elements as well) can be facilitated by the knowledge of the syntactic and semantic constraints the verb imposes on the lexical fulfillment of its argument positions In particular, the number of verb arguments; their structural and distributional type; the prepositions the verb selects to introduce its essential complements; the main shape-changes that these structures can undergo; and other relevant linguistic information; besides its intrinsic linguistic interest, all this data can be put to use to improve parsing strategies, word-sense disambiguation, question-answer systems, computer-assisted language learning systems, among other applications Above all, an inventory of basic word senses and their corresponding structures is necessary, and this is the aim of the ViPEr project This paper presents the current state of the Lexicon-Grammar of European Portuguese verbs The classification of European Portuguese verb constructions is largely based on the methodology presented by M GROSS (1975, 1981, 1996) and his collaborators under the Lexicon-Grammar theoretical framework (see LAMIROY (1998) for an overview) The classification proper is directly inspired in the synthesis of LECLERE (2002) In the following, the main linguistic criteria that were adopted in the classification are presented For lack of space, only the most salient classes and properties are presented The paper concludes with preliminary results from applying this new resource to real texts, and prepares future work
15 citations
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TL;DR: It is shown that the only possible convergence points in the vector case are the constrained local minima, and the main contribution of this paper consists in the extension of the CAM algorithm to vector problems.
15 citations
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13 Sep 2010TL;DR: In this article, a Boolean Satisfiability (SAT)-based algorithm for entailment in propositional circumscription is proposed, which is inspired by ideas commonly used in SAT-based model checking, namely counterexample guided abstraction refinement.
Abstract: Circumscription is a representative example of a nonmonotonic reasoning inference technique. Circumscription has often been studied for first order theories, but its propositional version has also been the subject of extensive research, having been shown equivalent to extended closed world assumption (ECWA). Moreover, entailment in propositional circumscription is a well-known example of a decision problem in the second level of the polynomial hierarchy. This paper proposes a new Boolean Satisfiability (SAT)-based algorithm for entailment in propositional circumscription that explores the relationship of propositional circumscription to minimal models. The new algorithm is inspired by ideas commonly used in SAT-based model checking, namely counterexample guided abstraction refinement. In addition, the new algorithm is refined to compute the theory closure for generalized close world assumption (GCWA). Experimental results show that the new algorithm can solve problem instances that other solutions are unable to solve.
15 citations
Authors
Showing all 967 results
Name | H-index | Papers | Citations |
---|---|---|---|
João Carvalho | 126 | 1278 | 77017 |
Jaime G. Carbonell | 72 | 496 | 31267 |
Chris Dyer | 71 | 240 | 32739 |
Joao P. S. Catalao | 68 | 1039 | 19348 |
Muhammad Bilal | 63 | 720 | 14720 |
Alan W. Black | 61 | 413 | 19215 |
João Paulo Teixeira | 60 | 636 | 19663 |
Bhiksha Raj | 51 | 359 | 13064 |
Joao Marques-Silva | 48 | 289 | 9374 |
Paulo Flores | 48 | 321 | 7617 |
Ana Paiva | 47 | 472 | 9626 |
Miadreza Shafie-khah | 47 | 450 | 8086 |
Susana Cardoso | 44 | 400 | 7068 |
Mark J. Bentum | 42 | 226 | 8347 |
Joaquim Jorge | 41 | 290 | 6366 |