2018
Autores
Branco, MC; Delgado, C; Marques, C;
Publicação
REVIEW OF MANAGERIAL SCIENCE
Abstract
This study investigates the sustainability reporting practices of companies based in the Nordic and the Mediterranean European countries for the period 2013-2015. Its purpose is to analyse to what extent, if any, are there differences in these practices. It seeks to capture the influence of national institutions and firm specific characteristics in sustainability reporting. Non-parametric statistics are used to analyse some factors which influence disclosure, namely country, industry affiliation, type of property, listing status and size. In accordance with the theoretical frame used, that of the varieties of capitalism approach, findings suggest that in general companies from Mediterranean European countries present higher levels of engagement with the Global Reporting Initiative.
2018
Autores
Sousa, JP; Ferreira, BM; Cruz, NA;
Publicação
2018 IEEE/OES AUTONOMOUS UNDERWATER VEHICLE WORKSHOP (AUV)
Abstract
Unmanned Underwater Vehicles (UUVs), such as Autonomous Underwater Vehicles (AUVs) and Remotely Operated Vehicles (ROVs) are versatile tools, suitable for many activities in different fields, and have seen an increase in usage, making them an area of interest in the study of robotics. The performance of any underwater vehicle in any given task is deeply affected by the precision of its localization system. The main challenge in underwater localization is the significant attenuation of any Radio Frequency (RF) signal underwater, which prevents the use of many common location methods such as the Global Positioning System (GPS). Many methods have been studied for the localization of UUVs, including the use of acoustic beacons. One of these methods is the use of a single moving beacon to obtain acoustic ranges, as opposed to a stationary single beacon, which restricts the UUV's trajectory or multiple beacons, involving more hardware, complicating missions' logistics and increasing costs. In this paper, a guidance algorithm based on the Fisher Information Matrix is proposed for an Autonomous Surface Vehicle to serve as a beacon vehicle and aid in the navigation of a UUV. The approach performances are assessed by means of simulations of the complete system under realistic conditions.
2018
Autores
Ferreira-Santos, D; Rodrigues, PP;
Publicação
International Journal of Data Science and Analytics
Abstract
2018
Autores
Royuela, S; Pinho, LM; Quinones, E;
Publicação
PROCEEDINGS OF THE 2018 DESIGN, AUTOMATION & TEST IN EUROPE CONFERENCE & EXHIBITION (DATE)
Abstract
The use of parallel heterogeneous embedded architectures is needed to implement the level of performance required in advanced safety-critical systems. Hence, there is a demand for using high level parallel programming models capable of efficiently exploiting the performance opportunities. In this paper, we evaluate the incorporation of OpenMP, a parallel programming model used in HPC, into Ada, a language spread in safety-critical domains. We demonstrate that the execution model of OpenMP is compatible with the recently proposed Ada tasklet model, meant to exploit fine-grain structured parallelism. Moreover, we show the compatibility of the OpenMP and tasklet models, enabling the use of OpenMP directives in Ada to further exploit unstructured parallelism and heterogeneous computation. Finally, we state the safety properties of OpenMP and analyze the interoperability between the OpenMP and Ada runtimes. Overall, we conclude that OpenMP can be effectively incorporated into Ada without jeopardizing its safety properties.
2018
Autores
Carneiro, I; Carvalho, S; Henrique, R; Oliveira, LM; Tuchin, VV;
Publicação
BIOPHOTONICS: PHOTONIC SOLUTIONS FOR BETTER HEALTH CARE VI
Abstract
Knowledge of the optical properties of tissues is necessary, since they change from tissue to tissue and can differ between normal and pathological conditions. These properties are used in light transport models with various areas of application. In general, tissues have significantly high scattering coefficient when compared to the absorption coefficient and such difference usually increases with decreasing wavelength. The study of the wavelength dependence of the optical properties has been already made for several animal and human tissues, but extensive research is still needed in this field. Considering that most of the Biophotonics techniques used in research and clinical practice use visible to NIR light, we have estimated the optical properties of colorectal muscle (muscularis propria) between 400 and 1000 nm. The samples used were collected from patients undergoing resection surgery for colorectal carcinoma. The estimated scattering coefficient for colorectal muscle decreases exponentially with wavelength from 122 cm(-1) at 400 nm to 95 cm(-1) at 650 nm and to 91 cm(-1) at 1000 nm. The absorption coefficient shows a wavelength dependence according to the behavior seen for other tissues, since it decreases from 8 cm(-1) at 400 nm to 2.6 cm(-1) at 650 nm and to 1.3 cm(-1) at 1000 nm. The estimated optical properties differ from the ones that we have previously obtained for normal and pathological colorectal mucosa. The data obtained in this study covers an extended spectral range and it can be used for planning optical clearing treatments for some wavelengths of interest.
2018
Autores
Almeida, JB; Barbosa, M; Barthe, G; Pacheco, H; Pereira, V; Portela, B;
Publicação
IEEE 31ST COMPUTER SECURITY FOUNDATIONS SYMPOSIUM (CSF 2018)
Abstract
We give a language-based security treatment of domain-specific languages and compilers for secure multi-party computation, a cryptographic paradigm that. enables collaborative computation over encrypted data. Computations are specified in a core imperative language, as if they were intended to be executed by a trusted-third party, and formally verified against. an information-flow policy modelling (an upper bound to) their leakage. This allows non-experts to assess the impact of performance driven authorized disclosure of intermediate values. Specifications are then compiled to multi-party protocols. We formalize protocol security using (distributed) probabilistic information-flow and prove security-preserving compilation: protocols only leak what. is allowed by the source policy. The proof exploits a natural but previously missing correspondence between simulation-based cryptographic proofs and (composable) probabilistic non-interference. Finally, we extend our framework to justify leakage cancelling, a domain-specific optimization that allows to first write an efficient specification that fails to meet the allowed leakage upper-bound, and then apply a probabilistic preprocessing that brings leakage to the acceptable range.
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