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Publications

2013

Real-time and continuous hand gesture spotting: An approach based on artificial neural networks

Authors
Neto, P; Pereira, D; Pires, JN; Moreira, AP;

Publication
ICRA

Abstract

2013

Hardware pipelining of repetitive patterns in processor instruction traces

Authors
Bispo, J; Cardoso, JMP; Monteiro, J;

Publication
Journal of Integrated Circuits and Systems

Abstract
Dynamic partitioning is a promising technique where computations are transparently moved from a General Purpose Processor (GPP) to a coprocessor during application execution. To be effective, the mapping of computations to the coprocessor needs to consider aggressive optimizations. One of the mapping optimizations is loop pipelining, a technique extensively studied and known to allow substantial performance improvements. This paper describes a technique for pipelining Megablocks, a type of runtime loop developed for dynamic partitioning. The technique transforms the body of Mega-blocks into an acyclic dataflow graph which can be fully pipe-lined and is based on the atomic execution of loop iterations. For a set of 9 benchmarks without memory operations, we generated pipelined hardware versions of the loops and esti-mate that the presented loop pipelining technique increases the average speedup of non-pipelined coprocessor accelerated designs from 1.6× to 2.2×. For a larger set of 61 benchmarks which include memory operations, we estimate through simulation a speedup increase from 2.5× to 5.6× with this technique.

2013

Register Transfer Level Workflow for Application and Evaluation of Soft Error Mitigation Techniques

Authors
Sousa, F; Anghinolfi, F; Ferreira, JC;

Publication
16TH EUROMICRO CONFERENCE ON DIGITAL SYSTEM DESIGN (DSD 2013)

Abstract
Digital circuits exposed to environments with high levels of radiation, such as those found in High Energy Physics experiments, are prone to Single Event Upsets. These upsets impact the reliability of the circuit. In order to mitigate the effects of the upsets, several well-known techniques for use with register transfer level (RTL) circuit descriptions have been proposed over the years. They typically have a large impact on circuit size and power consumption. Therefore, they are often applied only to the more critical modules of the system. Additionally, the manual implementation of those techniques has a significant cost in terms of time and design effort, involving both RTL changes and tailoring of the synthesis flow to avoid optimizing away the additional hardware. This paper describes an automated workflow that reduces the time for implementing SEU mitigation techniques, avoids the errors caused by manual alteration of the RTL descriptions, and enables the designer to explore different alternatives quickly. The paper describes the application of the workflow to three digital circuits and discusses the data obtained from the implementation of the different mitigation techniques.

2013

Thermo-Optic Variable Attenuator/Waveplate Based on Waveguides Patterned on Organic-Inorganic Hybrids

Authors
Vicente, CMS; Freitas, C; Marques, PV; Correia, SFH; Lima, PP; Carlos, LD; Andre, PS; Ferreira, RAS;

Publication
2013 15TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON 2013)

Abstract
This work reports a variable attenuator/waveplate based on thermo-optic (TO) effect induced on a waveguide patterned by direct UV-laser writing on films of organic-inorganic di-ureasil hybrids. The waveguide temperature was tuned inducing phase retardation between the transverse electric (TE) and transverse magnetic (TM) modes, resulting in a controllable waveplate. Furthermore, the waveguide TO actuation allows obtaining a variable optical attenuator. The relevant properties, such as attenuation, polarization dependence of the thermal actuation and power consumption will be presented in the NIR (1550 nm). The required electrical power and temperature variation to attain the optical signal extinction and the retardation phase of pi/2 were estimated.

2013

Automatic Decomposition of Safety Integrity Levels: Optimization by Tabu Search

Authors
Azevedo, LS; Parker, D; Walker, M; Papadopoulos, Y; Araujo, RE;

Publication
CARS@SAFECOMP

Abstract

2013

Factors Influencing Purchase Intention of Private Label Products: The Case of Smartphones

Authors
Coelho, DC; Meneses, RFC; Moreira, MRA;

Publication
EXPLORING SERVICES SCIENCE, IESS 2013

Abstract
A growth of the market share of private label brands has been observed in developed countries. This growth was initially confirmed for food and drugstore categories, but it quickly expanded to new product categories, particularly technology products. This study focus on a specific technology segment - the private label brands in smartphones, due to the growth observed in its demand, in recent years. In this context, we analyzed and studied the smartphone market and consumer, and examine the factors influencing purchase intention of private label smartphones. The literature review on private label technological products proved to be scarce, which raised a challenge in exploring the main differences among factors influencing purchase intention for this specific product category. In this study, through the development and application of an analytical model, we test a set of variables that resulted from the literature review, which could potentially influence the purchase intention of smartphones. We applied a questionnaire to a study population, and recorded 339 valid answers. The results were estimated in accordance with the Structural Equation Model. Our analysis highlights the importance given to technology by consumers, as well as price and quality. This study also revealed the importance of private label brands in a market which has as yet been underexplored.

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