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Publicações

2014

Automated Image Analysis of Lung Branching Morphogenesis from Microscopic Images of Fetal Rat Explants

Autores
Rodrigues, PL; Rodrigues, NF; Duque, D; Granja, S; Correia Pinto, J; Vilaca, JL;

Publicação
COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE

Abstract
Background. Regulating mechanisms of branching morphogenesis of fetal lung rat explants have been an essential tool for molecular research. This work presents a new methodology to accurately quantify the epithelial, outer contour, and peripheral airway buds of lung explants during cellular development from microscopic images. Methods. The outer contour was defined using an adaptive and multiscale threshold algorithm whose level was automatically calculated based on an entropy maximization criterion. The inner lung epithelium was defined by a clustering procedure that groups small image regions according to the minimum description length principle and local statistical properties. Finally, the number of peripheral buds was counted as the skeleton branched ends from a skeletonized image of the lung inner epithelia. Results. The time for lung branching morphometric analysis was reduced in 98% in contrast to the manual method. Best results were obtained in the first two days of cellular development, with lesser standard deviations. Nonsignificant differences were found between the automatic and manual results in all culture days. Conclusions. The proposed method introduces a series of advantages related to its intuitive use and accuracy, making the technique suitable to images with different lighting characteristics and allowing a reliable comparison between different researchers.

2014

Efficient state-based CRDTs by decomposition

Autores
Almeida, PS; Shoker, A; Baquero, C;

Publicação
PaPEC@EuroSys

Abstract
Eventual consistency is a relaxed consistency model used in large-scale distributed systems that seek better availability when consistency can be delayed. CRDTs are distributed data types that make eventual consistency of a distributed object possible and non ad-hoc. Specifically, state-based CRDTs achieve this through shipping the entire replica state that is, eventually, merged to other replicas ensuring conver- gence. This imposes a large communication overhead when the replica size or the number of replicas gets larger. In this work, we introduce a decomposable version of state-based CRDTs, called Delta State-based CRDTs (d-CRDT). A d-CRDT is viewed as a join of multiple fine-grained CRDTs of the same type, called deltas (d). The deltas are produced by applying d-mutators, on a replica state, which are mod- ified versions of the original CRDT mutators. This makes it possible to ship small deltas (or batches) instead of ship- ping the entire state. The challenges are to make the join of deltas equivalent to the join of the entire object in clas- sical state-based CRDTs, and to find a way to derive the d-mutators. We address this challenge in this work, and we explore the minimal requirements that a communication al- gorithm must offer according to the guarantees provided by the underlying messaging middleware. Copyright © 2007 by the Association for Computing Machinery, Inc.

2014

Generating attribute grammar-based bidirectional transformations from rewrite rules

Autores
Martins, P; Saraiva, J; Fernandes, JP; Wyk, EV;

Publicação
PEPM

Abstract
Higher order attribute grammars provide a convenient means for specifying uni-directional transformations, but they provide no direct support for bidirectional transformations. In this paper we show how rewrite rules (with non-linear right hand sides) that specify a forward/get transformation can be inverted to specify a partial backward/put transformation. These inverted rewrite rules can then be extended with additional rules based on characteristics of the source language grammar and forward transformations to create, under certain circumstances, a total backward transformation. Finally, these rules are used to generate attribute grammar specifications implementing both transformations. Categories and Subject Descriptors D.3.3 [Programming Languages]: Data Types and Structures, Recursion; F.3.2 [Logics and Meanings of Programs]: Semantics of Programming Languages- Algebraic approaches to semantics; I.1.1 [Symbolic and Algebraic Manipulation]: Expressions and Their Representation.

2014

Conflict Resolution and its Context

Autores
Carneiro, D; Novais, P; Neves, J;

Publicação
Law, Governance and Technology Series

Abstract

2014

Are HOV/eco-lanes a sustainable option to reducing emissions in a medium-sized European city?

Autores
Fontes, T; Fernandes, P; Rodrigues, H; Bandeira, JM; Pereira, SR; Khattak, AJ; Coelho, MC;

Publicação
TRANSPORTATION RESEARCH PART A-POLICY AND PRACTICE

Abstract
Innovative traffic management measures are needed to reduce transportation-related emissions. While in Europe, road lane management has focused mainly on introduction of bus lanes, the conversion to High Occupancy Vehicles (HOV) and eco-lanes (lanes dedicated to vehicles running on alternative fuels) has not been studied comprehensively. The objectives of this research are to: (1) Develop an integrated microscopic modeling platform calibrated with real world data to assess both traffic and emissions impacts of future Traffic Management Strategies (TMS) in an urban area; (2) Evaluate the introduction of HOV/eco-lanes in three different types of roads, freeway, arterial and urban routes, in an European medium-sized city and its effects in terms of emissions and traffic performance. The methodology consists of three distinct phases: (a) Traffic and road inventory data collection; (b) Traffic and emissions simulation using an integrated platform of microscopic simulation; and (c) Evaluation of scenarios. For the baseline scenario, the statistical analysis shows valid results. The results show that HOV and eco-lanes in a medium European city are feasible, and when the Average Occupancy of Vehicles (AOV) increases, on freeways, the majority of vehicles can reduce their travel time (2%) with a positive impact in terms of total emissions (-38% NOx, -39% HC, -43% CO and -37% CO2). On urban and arterial corridors, the reduction in emissions could be achieved only if the AOV increases from 1.50 to 1.70 passengers/vehicle. Total emissions of the corridor with an AOV of 1.70 passengers/vehicle can be reduced up to 35-36% for the urban route while the values can be reduced by 36-39% for the arterial road. With the introduction of Hybrid Electric Vehicles (HEV) and Electric Vehicles (EV) it is possible to reduce emissions, although the introduction of eco-lanes did not show significant reductions in emissions. When both policies are simulated together, an emissions improvement is observed for the arterial route and for two of the scenarios.

2014

Automatic modeling of pectus excavatum corrective prosthesis using artificial neural networks

Autores
Rodrigues, PL; Rodrigues, NF; Pinho, ACM; Fonseca, JC; Correia Pinto, J; Vilaca, JL;

Publicação
MEDICAL ENGINEERING & PHYSICS

Abstract
Pectus excavatum is the most common deformity of the thorax. Pre-operative diagnosis usually includes Computed Tomography (CT) to successfully employ a thoracic prosthesis for anterior chest wall remodeling. Aiming at the elimination of radiation exposure, this paper presents a novel methodology for the replacement of CT by a 3D laser scanner (radiation-free) for prosthesis modeling. The complete elimination of CT is based on an accurate determination of ribs position and prosthesis placement region through skin surface points. The developed solution resorts to a normalized and combined outcome of an artificial neural network (ANN) set. Each ANN model was trained with data vectors from 165 male patients and using soft tissue thicknesses (STT) comprising information from the skin and rib cage (automatically determined by image processing algorithms). Tests revealed that ribs position for prosthesis placement and modeling can be estimated with an average error of 5.0 +/- 3.6 mm. One also showed that the ANN performance can be improved by introducing a manually determined initial STT value in the ANN normalization procedure (average error of 2.82 +/- 0.76 mm). Such error range is well below current prosthesis manual modeling (approximately 11 mm), which can provide a valuable and radiation-free procedure for prosthesis personalization.

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