3135083 documents found, page 313172 of 313509

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Evaluation of an automatic dry eye test using MCDM methods and rank correlation

Barral,DiegoPeteiro; Beatriz Remeseiro López; Méndez,Rebeca; Penedo,ManuelG.

Dry eye is an increasingly common disease in modern society which affects a wide range of population and has a negative impact on their daily activities, such as working with computers or driving. It can be diagnosed through an automatic clinical test for tear film lipid layer classification based on color and texture analysis. Up to now, researchers have mainly focused on the improvement of the image analysis ...

Date: 2017   |   Origin: INESC TEC

Phase-sensitive Optical Time Domain Reflectometer Assisted by First-order Raman...

Martins,HF; Martin Lopez,S; Corredera,P; Filograno,ML; Orlando Frazão; Gonzalez Herraez,M

In this study, the authors present an experimental and theoretical description of the use of first order Raman amplification to improve the performance of a Phase-sensitive optical time domain reflectometer (phi OTDR) when used for vibration measurements over very long distances. A special emphasis is given to the noise which is carefully characterized and minimized along the setup. A semiconductor optical ampl...

Date: 2014   |   Origin: INESC TEC

Mapping seaweed beds using multispectral imagery retrieved by unmanned aerial v...

Azevedo,I; Adão,T; Pádua,L; Borges,D; Gonçalves,J; Sousa Pinto,I; Sousa,J; Emanuel Peres Correia

Date: 2019   |   Origin: INESC TEC

Incremental scenario representations for autonomous driving using geometric pol...

Miguel Riem Oliveira; Santos,V; Sappa,AD; Dias,P; António Paulo Moreira

When an autonomous vehicle is traveling through some scenario it receives a continuous stream of sensor data. This sensor data arrives in an asynchronous fashion and often contains overlapping or redundant information. Thus, it is not trivial how a representation of the environment observed by the vehicle can be created and updated over time. This paper presents a novel methodology to compute an incremental 3D ...

Date: 2016   |   Origin: INESC TEC

Advanced voltage control for smart microgrids using distributed energy resources

Olival,PC; André Guimarães Madureira; Manuel Matos

Large scale integration of distributed generation (DG), particularly based on variable renewable energy sources (RES), in low voltage (LV) distribution networks brings significant challenges to operation. This paper presents a new methodology for mitigating voltage problems in LV networks, in a future scenario with high integration of distributed energy resources (DER), taking advantage of these resources based...

Date: 2017   |   Origin: INESC TEC

Experimental and analytical approach on the Trombe wall thermal performance par...

Briga Sa,A; José Boaventura; Lanzinha,JC; Paiva,A

An analytical and experimental analysis on the Trombe wall thermal performance was carried out for different conditions of ventilation openings and occlusion device operation. Experimental results allowed to determine temperature fluctuation, heat flux, heat delay and air velocity at the ventilation openings. A calculation methodology was applied to estimate the heat gains and losses through the system using ex...

Date: 2017   |   Origin: INESC TEC

Simplified back-propagation for fibre nonlinearity compensation employing multi...

Luís Manuel Pessoa; Henrique Salgado; Darwazeh,I

In this paper we investigate the efficacy of applying the coupled field back-propagation algorithm as a post-compensation method for nonlinearity mitigation in a coherently detected fibre optic long-haul system using multi-band orthogonal frequency division multiplexed signals. Specifically, we analyze the impact of varying the band-spacing and the number of bands. We find that its efficacy is higher for largel...

Date: 2013   |   Origin: INESC TEC

E-commerce: A brief historical and conceptual approach

Meira,D; Magalhaes,L; Pereira,F; Emanuel Peres Correia

Despite being a recent phenomenon and being in constant evolution, e-commerce (EC) is already embedded in current society. However, difficulties in establishing a universally accepted definition have resulted in a multiplicity of meanings that sometimes merge with the e-business (EB) concept. This article presents a brief historical and conceptual evolution of EC and some of its most significant aspects. Copyri...

Date: 2014   |   Origin: INESC TEC

Model inference for spreadsheets

Jácome Costa Cunha; Erwig,M; Jorge Cunha Mendes; João Alexandre Saraiva

Many errors in spreadsheet formulas can be avoided if spreadsheets are built automatically from higher-level models that can encode and enforce consistency constraints in the generated spreadsheets. Employing this strategy for legacy spreadsheets is difficult, because the model has to be reverse engineered from an existing spreadsheet and existing data must be transferred into the new model-generated spreadshee...

Date: 2016   |   Origin: INESC TEC

Spatial considerations of an area restriction model for identifying harvest blo...

Kašpar,J; Perez,GFE; Adelaide Cerveira; Marušák,R

In the past few decades, ecological and environmental issues have dominated the forest industry worldwide, but economic aspects have been much less studied in this dynamic period. However, a sustainable and efficient forest biomass supply is critical for socio-economic development in many regions, particularly in rural areas. Nature protection efforts have contributed to reduced harvesting quotas, which have re...

Date: 2016   |   Origin: INESC TEC

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