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Publicações

2013

COMPRESSIVE SENSING FOR INCOHERENT IMAGING SYSTEMS WITH OPTICAL CONSTRAINTS

Autores
Renna, F; Rodrigues, MRD; Chen, MH; Calderbank, R; Carin, L;

Publicação
2013 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING (ICASSP)

Abstract
We consider the problem of linear projection design for incoherent optical imaging systems. We propose a computationally efficient method to obtain effective measurement kernels that satisfy the physical constraints imposed by an optical system, starting first from arbitrary kernels, including those that satisfy a less demanding power constraint. Performance is measured in terms of mutual information between the source input and the projection measurement, as well as reconstruction error for real world images. A clear improvement in the quality of image reconstructions is shown with respect to both random and adaptive projection designs in the literature.

2013

Batched Evaluation of Linear Tabled Logic Programs

Autores
Areias, M; Rocha, R;

Publicação
COMPUTER SCIENCE AND INFORMATION SYSTEMS

Abstract
Logic Programming languages, such as Prolog, provide a high-level, declarative approach to programming. Despite the power, flexibility and good performance that Prolog systems have achieved, some deficiencies in Prolog's evaluation strategy - SLD resolution - limit the potential of the logic programming paradigm. Tabled evaluation is a recognized and powerful technique that overcomes SLD's susceptibility in dealing with recursion and redundant sub-computations. In a tabled evaluation, there are several points where we may have to choose between different tabling operations. The decision on which operation to perform is determined by the scheduling algorithm. The two most successful tabling scheduling algorithms are local scheduling and batched scheduling. In previous work, we have developed a framework, on top of the Yap Prolog system, that supports the combination of different linear tabling strategies for local scheduling. In this work, we propose the extension of our framework to support batched scheduling. In particular, we are interested in the two most successful linear tabling strategies, the DRA and DRE strategies. To the best of our knowledge, no other Prolog system supports both strategies simultaneously for batched scheduling. Our experimental results show that the combination of the DRA and DRE strategies can effectively reduce the execution time for batched evaluation.

2013

DEDIS: distributed exact deduplication for primary storage infrastructures

Autores
Paulo, J; Pereira, J;

Publicação
SoCC

Abstract
Deduplication is now widely accepted as an efficient technique for reducing storage costs at the expense of some processing overhead, being increasingly sought in primary storage systems [7, 8] and cloud computing infrastructures holding Virtual Machine (VM) volumes [2, 1, 5]. Besides a large number of duplicates that can be found across static VM images [3], dynamic general purpose data from VM volumes allows space savings from 58% up to 80% if deduplicated in a cluster-wide fashion [1, 4]. However, some of these volumes persist latency sensitive data which limits the overhead that can be incurred in I/O operations. Therefore, this problem must be addressed by a cluster-wide distributed deduplication system for such primary storage volumes.

2013

Vehicle to Grid Decentralized Dispatch Control Using Consensus Algorithm with Constraints

Autores
Lucas, A; Chang, S;

Publicação
Smart Grid and Renewable Energy

Abstract

2013

A multi-energy modelling, simulation and optimization environment for urban energy infrastructure planning

Autores
Page, J; Basciotti, D; Pol, O; Fidalgo, JN; Couto, M; Aron, R; Chiche, A; Foumie, L;

Publicação
Proceedings of BS 2013: 13th Conference of the International Building Performance Simulation Association

Abstract
Tins paper presents a multi-energy modelling environment developed to simulate and optimize urban energy strategies, with a focus on urban energy infrastructure planning. A multi-scale approach is applied for modelling urban energy networks, considered as the backbone of urban energy infrastructure. This is complemented by the modelling of energy demand (to consider the costs and impacts of demand-side measures. The model is also linked to a set of optimization techniques in order to provide answers to urban energy infrastructure planning issues. Two case study applications follow the presentation of the chosen modelling principles to illustrate the type of answers that can be provided by the proposed modelling and optimization approach. Copyright © 2011 by IPAC'11/EPS-AG.

2013

Strain-Temperature Discrimination Using Multimode Interference in Tapered Fiber

Autores
Andre, RM; Biazoli, CR; Silva, SO; Marques, MB; Cordeiro, CMB; Frazao, O;

Publicação
IEEE PHOTONICS TECHNOLOGY LETTERS

Abstract
Tapering single-mode-multimode-single-mode structures to enhance sensitivity is proposed and experimentally demonstrated. 50-mm-long coreless multimode fiber sections are spliced between single-mode fibers (SMFs) and tapered. They are characterized in strain, and an increase in strain sensitivity is obtained with taper diameter reduction. Sensitivities as high as -23.69 pm/mu epsilon for the 15-mu m taper are attained. Temperature sensitivities also depend on taper diameter. A combination of two different diameter tapered SMF MMF-SMF structures, with cross-sensitivity to strain and temperature, is proposed as a sensing system for the simultaneous measurement of strain and temperature with resolutions of +/-5.6 mu epsilon and +/-1.6 degrees C, respectively. A good condition number of 3.16 is achieved with this sensing structure.

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