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Publications

2017

Demonstrating that Medical Devices Satisfy User Related Safety Requirements

Authors
Harrison, MD; Masci, P; Campos, JC; Curzon, P;

Publication
SOFTWARE ENGINEERING IN HEALTH CARE, SEHC 2014

Abstract
One way of contributing to a demonstration that a medical device is acceptably safe is to show that the device satisfies a set of requirements known to mitigate hazards. This paper describes experience using formal techniques to model an IV infusion device and to prove that the modelled device captures a set of requirements. The requirements chosen for the study are based on a draft proposal developed by the US Food and Drug Administration (FDA). A major contributor to device related errors are (user) interaction errors. For this reason the chosen models and requirements focus on user interface related issues.

2017

Plain and oscillatory solitons of the cubic complex Ginzburg-Landau equation with nonlinear gradient terms

Authors
Facao, M; Carvalho, MI;

Publication
PHYSICAL REVIEW E

Abstract
In this work, we present parameter regions for the existence of stable plain solitons of the cubic complex Ginzburg-Landau equation (CGLE) with higher-order terms associated with a fourth-order expansion. Using a perturbation approach around the nonlinear Schrdinger equation soliton and a full numerical analysis that solves an ordinary differential equation for the soliton profiles and using the Evans method in the search for unstable eigenvalues, we have found that the minimum equation allowing these stable solitons is the cubic CGLE plus a term known in optics as Raman-delayed response, which is responsible for the redshift of the spectrum. The other favorable term for the occurrence of stable solitons is a term that represents the increase of nonlinear gain with higher frequencies. At the stability boundary, a bifurcation occurs giving rise to stable oscillatory solitons for higher values of the nonlinear gain. These oscillations can have very high amplitudes, with the pulse energy changing more than two orders of magnitude in a period, and they can even exhibit more complex dynamics such as period-doubling.

2017

Making system of systems interoperable - The core components of the arrowhead framework

Authors
Varga, P; Blomstedt, F; Ferreira, LL; Eliasson, J; Johansson, M; Delsing, J; de Soria, IM;

Publication
JOURNAL OF NETWORK AND COMPUTER APPLICATIONS

Abstract
The objective of the Arrowhead Framework is to efficiently support the development, deployment and operation of interconnected, cooperative systems. It is based on the Service Oriented Architecture philosophy. The building elements of the framework are systems that provide and consume services, and cooperate as systems of systems. Some commonly used systems, such as orchestration, authorization or service registry are considered as core. These can be used by any system of systems that follow the guidelines of the Arrowhead Framework. Within the framework, systems - using different information exchange technologies during collaboration - are helped through various approaches. These include the so-called Interoperability Layer, as well as systems and services for translation. Furthermore, one of the main problems of developing such highly interoperable systems is the lack of understanding between various development groups. Adequate development and service documentation methodologies can help to overcome this issue. The design, development and verification methodology for each service, system and system of systems within the Arrowhead Framework supports that these can be implemented, verified, deployed, and run in an interoperable way. This paper presents an overview of the framework together with its core elements - and provides guidelines for the design and deployment of interoperable, Arrowhead-compliant cooperative systems.

2017

Nord Pool Ontology to Enhance Electricity Markets Simulation in MASCEM

Authors
Santos, G; Pinto, T; Praca, I; Vale, Z;

Publication
PROGRESS IN ARTIFICIAL INTELLIGENCE (EPIA 2017)

Abstract
This paper proposes the use of ontologies to enable information and knowledge exchange, to test different electricity market models and to allow players from different systems to interact in common market environments. Multi-agent based software is particularly well fitted to analyse dynamic and adaptive systems with complex interactions among its constituents, such as the complex and dynamic electricity markets. The main drivers are the markets' restructuring and evolution into regional and continental scales, along with the constant changes brought by the increasing necessity for an adequate integration of renewable energy sources. An ontology to represent the concepts related to the Nord Pool Elspot market is proposed. It is validated through a case study considering the simulation of Elspot market. Results show that heterogeneous agents are able to effectively participate in the simulation by using the proposed ontologies to support their communications with the Nord Pool market operator.

2017

Mobile-Based Analysis of Malaria-Infected Thin Blood Smears: Automated Species and Life Cycle Stage Determination

Authors
Rosado, L; da Costa, JMC; Elias, D; Cardoso, JS;

Publication
SENSORS

Abstract
Microscopy examination has been the pillar of malaria diagnosis, being the recommended procedure when its quality can be maintained. However, the need for trained personnel and adequate equipment limits its availability and accessibility in malaria-endemic areas. Rapid, accurate, accessible diagnostic tools are increasingly required, as malaria control programs extend parasite-based diagnosis and the prevalence decreases. This paper presents an image processing and analysis methodology using supervised classification to assess the presence of malaria parasites and determine the species and life cycle stage in Giemsa-stained thin blood smears. The main differentiation factor is the usage of microscopic images exclusively acquired with low cost and accessible tools such as smartphones, a dataset of 566 images manually annotated by an experienced parasilogist being used. Eight different species-stage combinations were considered in this work, with an automatic detection performance ranging from 73.9% to 96.2% in terms of sensitivity and from 92.6% to 99.3% in terms of specificity. These promising results attest to the potential of using this approach as a valid alternative to conventional microscopy examination, with comparable detection performances and acceptable computational times.

2017

Simultaneous Plasmonic Measurement of Refractive Index and Temperature Based on a D-Type Fiber Sensor With Gold Wires

Authors
Santos, DF; Guerreiro, A; Baptista, JM;

Publication
IEEE SENSORS JOURNAL

Abstract
This paper presents an optical fiber sensor, that uses surface plasmon resonance on metallic wires to directly and simultaneously measure both the refractive index and the temperature. The sensor is constituted by gold wires on a D-type fiber engineered, using numerical simulations based on the finite-element method to support plasmon modes with strong dependencies to either one of the measured parameters. In particular, the influence of the temperature on the structure of the plasmon modes results from contributions from the thermooptic effect in the fiber core and sensing layer, and phononelectron scattering along with electron-electron scattering in the metal wire. The performance of the sensor is evaluated in terms of its sensitivity and resolution.

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