3135083 documents found, page 313160 of 313509
Temperature-independent torsion sensor based on "figure-of-eight" fiber loop mi...
Silva,RM; Ribeiro,ABL; Orlando FrazãoAn interrogation sensor system combining the "figure-of-eight" fiber loop mirror using a single directional 3×3 fiber optic coupler was proposed. One fiber loop mirror was formed by inserting a length of high birefringent optical fiber at the input ports of the 3×3 coupler. Splicing the output ports of the 3×3 coupler between them created the other fiber loop mirror. The introduction of this second loop gave ri...
Recycling old screen-printed electrodes with newly designed plastic antibodies ...
Queiros,RB; Guedes,A; Paulo Vicente Marques; Noronha,JP; Sales,MGFUsing low cost portable devices that enable a single analytical step for screening environmental contaminants is today a demanding issue. This concept is here tried out by recycling screen-printed electrodes that were to be disposed of and by choosing as sensory element a low cost material offering specific response for an environmental contaminant. Microcystins (MCs) were used as target analyte, for being dang...
Fiber Cavity Ring Down and Gain Amplification Effect
Susana Oliveira Silva; Magalhaes,R; Ana Perez Herrera,RA; Lopez Amo,M; Manuel Joaquim Marques; Orlando FrazãoThe effect of an erbium-doped fiber amplifier (EDFA) placed inside the fiber ring of a cavity ring down (CRD) configuration is studied. The limitations and advantages of this configuration are discussed, and the study of the ring-down time as a function of the current applied and gain to the EDFA is also presented. In this case, the power fluctuations in the output signal are strongly dependent on the cavity ri...
Sizing and siting static synchronous compensator devices in the Portuguese tran...
Pedro Pereira Barbeiro; Carlos Moreira; Keko,H; Henrique Silva Teixeira; Rosado,N; Moreira,J; Rodrigues,RThis study presents a methodology for siting and sizing static synchronous compensator (STATCOM) devices in the Portuguese transmission system in order to improve system security following severe grid faults. Security issues arise since the Portuguese transmission system incorporates significant levels of wind generation without fault ride through and reactive current injection capabilities during grid faults. ...
Assessing the evolution of school performance and value-added: trends over four...
Portela,MC; Ana Camanho; Keshvari,AThis paper explores the changes in value added (VA) of a sample of schools for cohorts of students finishing secondary education between 2005 and 2008. VA estimates are based on distance measures obtained from DEA models. These measures are computed for each pupil in each school, and evaluate the distance between the school frontier in a given year and a pooled frontier comprising all schools analysed. The scho...
On scaling dynamic programming problems with a multithreaded tabling, Prolog sy...
Miguel Gonçalves Areias; Ricardo RochaTabling is a powerful implementation technique that improves the declarativeness and expressiveness of traditional Prolog systems in dealing with recursion and redundant computations. It can be viewed as a natural tool to implement dynamic programming problems, where a general recursive strategy divides a problem in simple sub-problems that are often the same. When tabling is combined with multithreading, we ha...
Kalman filter-based yaw angle estimation by fusing inertial and magnetic sensin...
Neto,P; Mendes,N; António Paulo MoreiraPurpose - The purpose of this paper is to achieve reliable estimation of yaw angles by fusing data from low-cost inertial and magnetic sensing. Design/methodology/approach - In this paper, yaw angle is estimated by fusing inertial and magnetic sensing from a digital compass and a gyroscope, respectively. A Kalman filter estimates the error produced by the gyroscope. Findings - Drift effect produced by the gyros...
Management Driven Hybrid Multicast Framework for Content Aware Networks
Iorga,R; Borcoci,E; Miruta,R; António Pinto; Carneiro,G; Calcada,TThe need for better adaptation of networks to transported flows has led to research on new approaches such as content aware networks and network aware applications. In parallel, recent developments of multimedia and content oriented services and applications such as IPTV, video streaming, video on demand, and Internet TV reinforced interest in multicast technologies. IP multicast has not been widely deployed du...
InGaZnO TFT behavioral model for IC design
Bahubalindrun,P; Vítor Grade Tavares; Barquinha,P; de Oliveira,PG; Martins,R; Fortunato,EThis paper presents a behavioral model for amorphous indium-gallium-zinc oxide thin-film transistor using artificial neural network (ANN) based equivalent circuit (EC) approach to predict static and dynamic behavior of the device. In addition, TFT parasitic capacitances (C-GS and C-GD) characterization through measurements is also reported. In the proposed model, an EC is derived from the device structure, in t...
Couillard: Parallel programming via coarse-grained Data-flow Compilation
Marzulo,LAJ; Alves,TAO; Franca,FMG; Vítor Santos CostaData-flow is a natural approach to parallelism. However, describing dependencies and control between fine-grained data-flow tasks can be complex and present unwanted overheads. TALM (TALM is an Architecture and Language for Multi-threading) introduces a user-defined coarse-grained parallel data-flow model, where programmers identify code blocks, called super-instructions, to be run in parallel and connect them ...