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Publications

2015

A Clear Picture of Lens Laws - Functional Pearl

Authors
Fischer, S; Hu, Z; Pacheco, H;

Publication
Mathematics of Program Construction - 12th International Conference, MPC 2015, Königswinter, Germany, June 29 - July 1, 2015. Proceedings

Abstract
A lens is an optical device which refracts light. Properly adjusted, it can be used to project sharp images of objects onto a screen— a principle underlying photography as well as human vision. Striving for clarity, we shift our focus to lenses as abstractions for bidirectional programming. By means of standard mathematical terminology as well as intuitive properties of bidirectional programs, we observe different ways to characterize lenses and show exactly how their laws interact. Like proper adjustment of optical lenses is essential for taking clear pictures, proper organization of lens laws is essential for forming a clear picture of different lens classes. Incidentally, the process of understanding bidirectional lenses clearly is quite similar to the process of taking a good picture. By showing that it is exactly the backward computation which defines lenses of a certain standard class, we provide an unusual perspective, as contemporary research tends to focus on the forward computation. © Springer International Publishing Switzerland 2015

2015

Thread-aware logic programming for data-driven parallel programs

Authors
Cruz, F; Rocha, R; Goldstein, SC;

Publication
CEUR Workshop Proceedings

Abstract
Declarative programming in the style of functional and logic programming has been hailed as an alternative parallel programming style where computer programs are automatically parallelized without programmer control. Although this approach removes many pitfalls of explicit parallel programming, it hides important information about the underlying parallel architecture that could be used to improve the scalability and efficiency of programs. In this paper, we present a novel programming model that allows the programmer to reason about thread state in data-driven declarative programs. This abstraction has been implemented on top of Linear Meld, a linear logic programming language that is designed for writing graphbased programs. Wepresent several programs that show theflavorofour new programming model, including graph algorithms and a machine learning algorithm. Our goal is to show thatitis possible to take advantage of architectural details without losing the key advantages of logic programming.

2015

<i>Tempus</i>: Dynamic Interface in Biocyber Body

Authors
Barradas, T; Coelho, J; Tavares, M;

Publication
7TH INTERNATIONAL CONFERENCE ON DIGITAL ARTS (ARTECH 2015)

Abstract

2015

Spatio-angular minimum-variance tomographic controller for multi-object adaptive-optics systems

Authors
Correia, CM; Jackson, K; Veran, JP; Andersen, D; Lardiere, O; Bradley, C;

Publication
APPLIED OPTICS

Abstract
Multi-object astronomical adaptive optics (MOAO) is now a mature wide-field observation mode to enlarge the adaptive-optics-corrected field in a few specific locations over tens of arcminutes. The work-scope provided by open-loop tomography and pupil conjugation is amenable to a spatio-angular linear-quadratic-Gaussian (SA-LQG) formulation aiming to provide enhanced correction across the field with improved performance over static reconstruction methods and less stringent computational complexity scaling laws. Starting from our previous work [J. Opt. Soc. Am. A 31, 101 (2014)], we use stochastic time-progression models coupled to approximate sparse measurement operators to outline a suitable SA-LQG formulation capable of delivering near optimal correction. Under the spatio-angular framework the wavefronts are never explicitly estimated in the volume, providing considerable computational savings on 10-m-class telescopes and beyond. We find that for Raven, a 10-m-class MOAO system with two science channels, the SA-LQG improves the limiting magnitude by two stellar magnitudes when both the Strehl ratio and the ensquared energy are used as figures of merit. The sky coverage is therefore improved by a factor of similar to 5. (C) 2015 Optical Society of America

2015

An information system for the cutting stock problem with optimization of retail materials in stock

Authors
Mendes, J; Fernandes, P; Pereira, CS;

Publication
2015 10th Iberian Conference on Information Systems and Technologies, CISTI 2015

Abstract
Considering the new paradigm in the industry, where clients request small amounts of a growing range of products, the times of crisis and the fierce competition for businesses survival, it is crucial for Organizations to be able to reduce the waste of raw materials. In the manufacturing industry, the waste of materials could be minimized with the introduction of decision support systems in the process. In this paper we propose an information system that enables the optimization of purchases and consumption of materials, promoting waste reduction and boosting profitability. © 2015 AISTI.

2015

Fabry-Perot cavity based on silica tube for strain sensing at high temperatures

Authors
Ferreira, MS; Roriz, P; Bierlich, J; Kobelke, J; Wondraczek, K; Aichele, C; Schuster, K; Santos, JL; Frazao, O;

Publication
OPTICS EXPRESS

Abstract
In this work, a Fabry-Perot cavity based on a new silica tube design is proposed. The tube presents a cladding with a thickness of similar to 14 mu m and a hollow core. The presence of four small rods, of similar to 20 mu m diameter each, placed in diametrically opposite positions ensure the mechanical stability of the tube. The cavity, formed by splicing a section of the silica tube between two sections of single mode fiber, is characterized in strain and temperature (from room temperature to 900 degrees C). When the sensor is exposed to high temperatures, there is a change in the response to strain. The influence of the thermal annealing is investigated in order to improve the sensing head performance. (C)2015 Optical Society of America

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