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Institution

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 IssueDOI
TL;DR: In this article, a cross-coupling of two relaxation oscillators was proposed to reduce the phase-noise and quadrature error of RC-oscillators.
Abstract: Relaxation RC-oscillators are notorious for their poor phase-noise performance. However, there are reasons to expect a phase-noise reduction in quadrature oscillators obtained by cross-coupling two relaxation oscillators. We present measurements on 5 GHz oscillators, which show that in RC-oscillators the coupling reduces both the phase-noise and quadrature error, whereas in LC-oscillators the coupling reduces the quadrature error, but increases the phase-noise. A comparison using standard figures of merit indicates that quadrature RC-oscillators may be a viable alternative to LC-oscillators when area and cost are to be minimized. Copyright © 2009 John Wiley & Sons, Ltd.

25 citations

Journal ArticleDOI
TL;DR: In this article, the authors describe the development of an adaptive control law based on the exact feedback linearization and Lyapunov adaptation of the process dynamics applied to a solar furnace.

25 citations

Proceedings Article
01 Jan 2007
TL;DR: This paper presents the initial conceptual design of an authoring tool for the emergent narrative agent architecture FAtiMA that powers the virtual bullying drama FearNot!.
Abstract: In this paper we present the initial conceptual design of an authoring tool for the emergent narrative agent architecture FAtiMA that powers the virtual bullying drama FearNot!. We explain that the process of authoring emergent narrative to a large part consists of designing a planning domain for a virtual character planner and explain the difficulties this task poses to the non-technical author. After reviewing existing authoring tools and evaluating them in terms of their applicability to FAtiMA, we introduce a novel concept of approaching the authoring task, in which the author is playing through example story lines that are used to gradually increase the knowledge and intelligence of a virtual character. This concept is extended by a mixed initiative feature, which allows the author to cooperate with the character planners while providing the example stories. Finally we concretize our idea and explain our intended implementation of it within the FearNot! Framework. We believe that our design, although being specified with a particular architecture (FAtiMA) in mind, may provide some interesting ideas to others, who are trying to solve the authoring problem for interactive storytelling sys-

25 citations

Journal ArticleDOI
TL;DR: Results show that visual changes should be kept to a minimum; touch points should be shifted upward and to the opposite side of the hand used to type; single touch keyboards perform better than multi-touch; and omitting keys below a certain time threshold minimizes accidental insertions.
Abstract: Touch screen interfaces are increasingly more popular. However, they lack haptic feedback, making it harder to perform certain tasks, such as text entry, where users have to constantly select one of many small targets. This problem particularly affects older users, whose deteriorating physical and cognitive conditions, combined with their unfamiliarity with technology, can discourage them from using touch devices. The goal of this work was to thoroughly understand older adults touch typing behavior, in order to develop text-entry solutions more appropriate to their needs, which will enhance their typing performance. On a first phase, a baseline QWERTY keyboard and five different variants were developed that mostly used a text prediction algorithm to suggest the most probable keys or words. These keyboards were evaluated on a baseline study with 20 younger adults in order to find the most promising ones, which were then used in a study with 20 older adults. The older adults study revealed more about their typing behavior and therefore created four new variants to be used in a simulation study. Results show that visual changes should be kept to a minimum; touch points should be shifted upward and to the opposite side of the hand used to type; single touch keyboards perform better than multi-touch; and omitting keys below a certain time threshold minimizes accidental insertions.

25 citations

Proceedings ArticleDOI
01 Sep 2008
TL;DR: The present study provides the first analytical model of multi-version concurrency control, currently very popular among mainstream commercial and open source database systems thanks to its ability to well cope with read intensive workloads.
Abstract: In this article we present a performance model for multi-version concurrency control (MVCC). This type of concurrency control is currently very popular among mainstream commercial and open source database systems thanks to its ability to well cope with read intensive workloads, as in the case of transaction profiles proper of Web applications. To build the model we had to tackle the intrinsic higher complexity of MVCC when compared to traditional concurrency control mechanisms (i.e. 2-phase-locking and optimistic ones), such as the joint use of locks and aborts to resolve direct conflicts among write accesses to the same data item, and the management of multiple data versions. We validate our analytical model via an extensive simulation study, considering both uniform and skewed data accesses, as well as differentiated transaction profiles. To the best of our knowledge, the present study provides the first analytical model of MVCC.

25 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