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Publications

2017

A Hazard Analysis Method for Systematic Identification of Safety Requirements for User Interface Software in Medical Devices

Authors
Masci, P; Zhang, Y; Jones, PL; Campos, JC;

Publication
Software Engineering and Formal Methods - 15th International Conference, SEFM 2017, Trento, Italy, September 4-8, 2017, Proceedings

Abstract
Formal methods technologies have the potential to verify the usability and safety of user interface (UI) software design in medical devices, enabling significant reductions in use errors and consequential safety incidents with such devices. This however depends on comprehensive and verifiable safety requirements to leverage these techniques for detecting and preventing flaws in UI software that can induce use errors. This paper presents a hazard analysis method that extends Leveson’s System Theoretic Process Analysis (STPA) with a comprehensive set of causal factor categories, so as to provide developers with clear guidelines for systematic identification of use-related hazards associated with medical devices, their causes embedded in UI software design, and safety requirements for mitigating such hazards. The method is evaluated with a case study on the Gantry-2 radiation therapy system, which demonstrates that (1) as compared to standard STPA, our method allowed us to identify more UI software design issues likely to cause use-related hazards; and (2) the identified UI software design issues facilitated the definition of precise, verifiable safety requirements for UI software, which could be readily formalized in verification tools such as Prototype Verification System (PVS). © Springer International Publishing AG (outside the US) 2017.

2017

State feedback control for DC-photovoltaic systems

Authors
Fernandes, D; Almeida, R; Guedes, T; Sguarezi Filho, A; Costa, F;

Publication
Electric Power Systems Research

Abstract

2017

Inferência Estatística - Problemas resolvidos e propostos com aplicações em R

Authors
Fernanda Figueiredo; Adelaide Figueiredo; Alexandra Ramos; Paulo Teles;

Publication

Abstract

2017

Spacial Aliasing Artefact Detection on T1-Weighted MRI Images

Authors
Teixeira, JF; Oliveira, HP;

Publication
PATTERN RECOGNITION AND IMAGE ANALYSIS (IBPRIA 2017)

Abstract
Magnetic Resonance Imaging (MRI) exams suffer from undesirable structure replicating and overlapping effects on certain acquisition settings. These are called Spatial Aliasing Artefacts (SAA) and their presence interferes with the segmentation of other anatomical structures. This paper addresses the segmentation of the SAA in T1-weighted MRI image sets, in order to effectively remove their influence over the legitimately positioned body structures. The proposed method comprises an initial thresholding, employing the Triangle method, an aggregation of neighboring voxels through Region Growing. Further refinement of the objects contour is obtained with Convex Hull and a Minimum Path algorithm applied to two orthogonal planes (Sagittal and Axial). Some experiments concerning the extension of the pipeline used are reported and the results seem promising. The average contour distance concerning the Ground Truth (GT) rounds 2.5mm and area metrics point out average overlaps above 64% with the GT. Some issues concerning the fusion between the output from the two planes are to be perfected. Nevertheless, the results seems sufficient to neutralize the influence of SAA and expedite the downstream anatomical segmentation tasks.

2017

Autonomous Quadrotor for accurate positioning

Authors
Moraes, L; Carmo, LC; Campos, RF; Jucá, MA; Moreira, LS; Carvalho, JP; Texeira, AM; Silveira, DD; Coelho, TVN; Luis, A; Marcato, M; Dos Santos, AB;

Publication
IEEE Aerospace and Electronic Systems Magazine

Abstract
Surveillance missions in vast, difficult access environments are responsible for logistic difficulties in comparison to using an in loco monitoring team. For this and many other reasons, solutions with robotic platforms such as unmanned aerial vehicles (UAVs), present economic advantages. © 1986-2012 IEEE.

2017

The Analogue Quantum Mechanical of Plasmonic Atoms

Authors
Alves, RA; Silva, NA; Costa, JC; Gomes, M; Guerreiro, A;

Publication
THIRD INTERNATIONAL CONFERENCE ON APPLICATIONS OF OPTICS AND PHOTONICS

Abstract
Localized plasmons in metallic nanostructures present strong analogies with Quantum Mechanical problems of particles trapped in potential wells. In this paper we take this analogy further using the Madelung Formalism of Quantum Mechanics to express the fluid equations describing the charge density of the conduction electrons and corresponding interaction with light in terms of an effective generalized Non-linear Schrodinger equations. Within this context, it is possible to develop the analogy of a plasmonic atom and molecule that exhibits Rabi oscillations, Stark effect, among other Quantum Mechanical effects.

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