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Publications

2016

Central Medialness Adaptive Strategy for 3D Lung Nodule Segmentation in Thoracic CT Images

Authors
Goncalves, L; Novo, J; Campilho, A;

Publication
IMAGE ANALYSIS AND RECOGNITION (ICIAR 2016)

Abstract
In this paper, a Hessian-based strategy, based on the central medialness adaptive principle, was adapted and proposed in a multiscale approach for the 3D segmentation of pulmonary nodules in chest CT scans. This proposal is compared with another well stated Hessian based strategy of the literature, for nodule extraction, in order to demonstrate its accuracy. Several scans from the Lung Image Database Consortium and Image Database Resource Initiative (LIDC-IDRI) database were employed in the test and validation procedure. The scans include a large and heterogeneous set of 569 solid and mostly solid nodules with a large variability in the nodule characteristics and image conditions. The results demonstrated that the proposal offers correct results, similar to the performance of the radiologists, providing accurate nodule segmentations that perform the desirable scenario for a posterior analysis and the eventual lung cancer diagnosis.

2016

Novel Linear Analog-Adder Using a-IGZO TFTs

Authors
Bahubalindruni, PG; Tavares, VG; Fortunato, E; Martins, R; Barquinha, P;

Publication
2016 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS (ISCAS)

Abstract
A novel linear analog adder is proposed only with n-type enhancement IGZO TFTs that computes summation of four voltage signals. However, this design can be easily extended to perform summation of higher number of signals, just by adding a single TFT for each additional signal in the input block. The circuit needs few number of transistors, only a single power supply irrespective of the number of voltage signals to be added, and offers good accuracy over a reasonable range of input values. The circuit was fabricated on glass substrate with the annealing temperature not exceeding 200 degrees C. The circuit performance is characterized from measurements under normal ambient at room temperature, with a power supply voltage of 12 V and a load of approximate to 4pF. The designed circuit has shown a linearity error of 2.3% (until input signal peak to peak value is 2 V), a power consumption of 78 mu W and a bandwidth of approximate to 115 kHz, under the worst case condition (when it is adding four signals with the same frequency). In this test setup, it has been noticed that the second harmonic is 32 dB below the fundamental frequency component. This circuit could offer an economic alternative to the conventional approaches, being an important contribution to increase the functionality of large area flexible electronics.

2016

Automatic Lumen Detection on Longitudinal Ultrasound B-Mode Images of the Carotid Using Phase Symmetry

Authors
Rouco, J; Azevedo, E; Campilho, A;

Publication
SENSORS

Abstract
This article describes a method that improves the performance of previous approaches for the automatic detection of the common carotid artery (CCA) lumen centerline on longitudinal B-mode ultrasound images. We propose to detect several lumen centerline candidates using local symmetry analysis based on local phase information of dark structures at an appropriate scale. These candidates are analyzed with selection mechanisms that use symmetry, contrast or intensity features in combination with position-based heuristics. Several experimental results are provided to evaluate the robustness and performance of the proposed method in comparison with previous approaches. These results lead to the conclusion that our proposal is robust to noise, lumen artifacts, contrast variations and that is able to deal with the presence of CCA-like structures, significantly improving the performance of our previous approach, from [GRAPHICS] of correct detections to [GRAPHICS] in a set of 200 images.

2016

EmbodiMentor: a science fiction prototype to embody different perspectives using augmented reality

Authors
Morgado, Leonel; Gütl, Christian; Stahlal, Aletha;

Publication
Proceedings of the 7th International Conference on Software Development and Technologies for Enhancing Accessibility and Fighting Info-exclusion, DSAI 2016, Vila Real, Portugal, December 1-3, 2016

Abstract
This paper describes the EmbodiMentor, an interaction concept and metaphor that aims to enable users to embody a different person or character's perspective, specify or modify his/her/its emotional elements and conditioning elements, and experience the resulting changes. Its use case scenario is the education and training of foreign languages and intercultural communication skills, were contextualization and first person experiences in common settings are key for practical skill acquisitions. It was born as the microscience-fiction prototype "Frances can't sleep. She crawls out of bed and with her EmbodiMentor runs through a range of a client's emotional states, pitching to each one. She then falls asleep." The application of the science fiction prototyping concept has been proven a strong approach to develop and investigate innovative applications of emerging technologies. © 2016 ACM.

2016

Optimization-Based Control of Constrained Nonlinear Systems with Continuous-Time Models: Adaptive Time-Grid Refinement Algorithms

Authors
Fontes, FACC; Paiva, LT;

Publication
NUMERICAL COMPUTATIONS: THEORY AND ALGORITHMS (NUMTA-2016)

Abstract
We address optimal control problems for nonlinear systems with pathwise state-constraints. These are challenging nonlinear problems for which the number of discretization points is a major factor determining the computational time. Also, the location of these points has a major impact in the accuracy of the solutions. We propose an algorithm that iteratively finds an adequate time-grid to satisfy some predefined error estimate on the obtained trajectories, which is guided by information on the adjoint multipliers. The obtained results show a highly favorable comparison against the traditional equidistant spaced time grid methods, including the ones using discrete time models. This way, continuous time plant models can be directly used. The discretization procedure can be automated and there is no need to select a priori the adequate time step. Even if the optimization procedure is forced to stop in an early stage, as might be the case in real time problems, we can still obtain a meaningful solution, although it might be a less accurate one. The extension of the procedure to a Model Predictive Control (MPC) context is proposed here. By defining a time dependent accuracy threshold, we can generate solutions that are more accurate in the initial parts of the receding horizon, which are the most relevant for MPC.

2016

QoS-as-a-Service in the Local Cloud

Authors
Ferreira, LL; Albano, M; Delsing, J;

Publication
2016 IEEE 21ST INTERNATIONAL CONFERENCE ON EMERGING TECHNOLOGIES AND FACTORY AUTOMATION (ETFA)

Abstract
This paper presents an architecture that supports Quality of Service (QoS) in an Arrowhead-compliant System of Systems (SoS). The Arrowhead Framework supports local cloud functionalities for automation applications, provided by means of a Service Oriented Architecture (SOA), by offering a number of services that ease application development. On such applications the QoS guarantees are required for service fruition, and are themselves requested as services from the framework. To fulfil this objective we start by describing the Arrowhead architecture and the components needed to dynamically in run-time negotiate a system configuration that guarantees the QoS requirements between application services.

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