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Publicações

2017

Products go Green: Worst-Case Energy Consumption in Software Product Lines

Autores
Couto, M; Borba, P; Cunha, J; Fernandes, JP; Pereira, R; Saraiva, J;

Publicação
21ST INTERNATIONAL SYSTEMS & SOFTWARE PRODUCT LINE CONFERENCE (SPLC 2017), VOL 1

Abstract
The optimization of software to be (more) energy efficient is becoming a major concern for the software industry. Although several techniques have been presented to measure energy consumption for software, none has addressed software product lines (SPLs). Thus, to measure energy consumption of a SPL, the products must be generated and measured individually, which is too costly. In this paper, we present a technique and a prototype tool to statically estimate the worst case energy consumption for SPL. The goal is to provide developers with techniques and tools to reason about the energy consumption of all products in a SPL, without having to produce, run and measure the energy in all of them. Our technique combines static program analysis techniques and worst case execution time prediction with energy consumption analysis. This technique analyzes all products in a feature-sensitive manner, that is, a feature used in several products is analyzed only once, while the energy consumption is estimated once per product. We implemented our technique in a tool called Serapis. We did a preliminary evaluation using a product line for image processing implemented in C. Our experiments considered 7 products from such line and our initial results show that the tool was able to estimate the worst-case energy consumption with a mean error percentage of 9.4% and standard deviation of 6.2% when compared with the energy measured when running the products.

2017

A diffusion-based connectivity map of the GPi for optimised stereotactic targeting in DBS

Autores
da Silva, NM; Ahmadi, SA; Tafula, SN; Silva Cunha, JPS; Botzel, K; Vollmar, C; Rozanski, VE;

Publicação
NEUROIMAGE

Abstract
Background: The GPi (globus pallidus internus) is an important target nucleus for Deep Brain Stimulation (DBS) in medically refractory movement disorders, in particular dystonia and Parkinson's disease. Beneficial clinical outcome critically depends on precise electrode localization. Recent evidence indicates that not only neurons, but also axonal fibre tracts contribute to promoting the clinical effect. Thus, stereotactic planning should, in the future, also take the individual course of fibre tracts into account. Objective: The aim of this project is to explore the GPi connectivity profile and provide a connectivity based parcellation of the GPi. Methods: Diffusion MRI sequences were performed in sixteen healthy, right-handed subjects. Connectivity-based parcellation of the GPi was performed applying two independent methods: 1) a hypothesis-driven, seed-to-target approach based on anatomic priors set as connectivity targets and 2) a purely data-driven approach based on k-means clustering of the GPi. Results: Applying the hypothesis-driven approach, we obtained five major parcellation clusters, displaying connectivity to the prefrontal cortex, the brainstem, the GPe (globus pallidus externus), the putamen and the thalamus. Parcellation clusters obtained by both methods were similar in their connectivity profile. With the data-driven approach, we obtained three major parcellation clusters. Inter individual variability was comparable with results obtained in thalamic parcellation. Conclusion: The three parcellation clusters obtained by the purely data-driven method might reflect GPi subdivision into a sensorimotor, associative and limbic portion. Clinical and physiological studies indicate greatest clinical DBS benefit for electrodes placed in the postero-ventro-lateral GPi, the region displaying connectivity to the thalamus in our study and generally attributed to the sensorimotor system. Clinical studies relating DBS electrode positions to our GPi connectivity map would be needed to complement our findings.

2017

Segmentation of the Rectus Abdominis Muscle Anterior Fascia for the Analysis of Deep Inferior Epigastric Perforators

Autores
Araújo, RJ; Oliveira, HP;

Publicação
PATTERN RECOGNITION AND IMAGE ANALYSIS (IBPRIA 2017)

Abstract
The segmentation of the anterior fascia of the rectus abdominis muscle is an important step towards the analysis of abdominal vasculature. It may advance Computer Aided Detection tools that support the activity of clinicians who study vessels for breast reconstruction using the Deep Inferior Epigastric Perforator flap. In this paper, we propose a two-fold methodology to detect the anterior fascia in Computerized Tomographic Angiography volumes. First, a slice-wise thresholding is applied and followed by a post-processing phase. Finally, an interpolation framework is used to obtain a final smooth fascia detection. We evaluated our method in 20 different volumes, by calculating the mean Euclidean distance to manual annotations, achieving subvoxel error.

2017

Prediction of Breast Deformities: A Step Forward for Planning Aesthetic Results After Breast Surgery

Autores
Bessa, S; Zolfagharnasab, H; Pereira, E; Oliveira, HP;

Publicação
PATTERN RECOGNITION AND IMAGE ANALYSIS (IBPRIA 2017)

Abstract
The development of a three-dimensional (3D) planing tool for breast cancer surgery requires the existence of proper deformable models of the breast, with parameters that can be manipulated to obtain the desired shape. However, modelling breast is a challenging task due to the lack of physical landmarks that remain unchanged after deformation. In this paper, the fitting of a 3D point cloud of the breast to a parametric model suitable for surgery planning is investigated. Regression techniques were used to learn breast deformation functions from exemplar data, resulting in comprehensive models easy to manipulate by surgeons. New breast shapes are modelled by varying the type and degree of deformation of three common deformations: ptosis, turn and top-shape.

2017

Six-Leg Single-Phase Multilevel Rectifier Inverter: PWM Strategies and Control

Autores
de Freitas, NB; Jacobina, CB; Maia, ACN; Melo, VFMB;

Publicação
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS

Abstract
This paper discusses a rectifier inverter composed of two three-leg converters with equal and unequal dc-links voltages connected in series. The operation with equal dc-links voltages divides equally the voltages in each converter. On the other hand, the operation with unequal dc-links voltages increases the number of voltage levels and contributes to reduce harmonic distortion and power losses. Space-vector and level-shifted techniques are discussed. The balance of separated dc sources using redundant voltage vectors is addressed in this paper. A closed-loop controller is used to control the average value of the dc voltages. Simulation results compare power losses and harmonic distortion of three-leg and six-leg topologies. Experimental results are provided to validate the feasibility of the system.

2017

Assessing the Gene Regulatory Landscape in 1,188 Human Tumors

Autores
Calabrese, C; Lehmann, K; Urban, L; Liu, F; Erkek, S; Fonseca, N; Kahles, A; Kilpinen-Barrett, LH; Markowski, J; Waszak, S; Korbel, J; Zhang, Z; Brazma, A; Raetsch, G; Schwarz, R; Stegle, O; PCAWG-3,;

Publicação

Abstract
Cancer is characterised by somatic genetic variation, but the effect of the majority of non-coding somatic variants and the interface with the germline genome are still unknown. We analysed the whole genome and RNA-seq data from 1,188 human cancer patients as provided by the Pan-cancer Analysis of Whole Genomes (PCAWG) project to map cis expression quantitative trait loci of somatic and germline variation and to uncover the causes of allele-specific expression patterns in human cancers. The availability of the first large-scale dataset with both whole genome and gene expression data enabled us to uncover the effects of the non-coding variation on cancer. In addition to confirming known regulatory effects, we identified novel associations between somatic variation and expression dysregulation, in particular in distal regulatory elements. Finally, we uncovered links between somatic mutational signatures and gene expression changes, including TERT and LMO2, and we explained the inherited risk factors in APOBEC-related mutational processes. This work represents the first large-scale assessment of the effects of both germline and somatic genetic variation on gene expression in cancer and creates a valuable resource cataloguing these effects.

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