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Publications

2014

RTFM-lang static semantics for systems with mixed criticality

Authors
Lindgren, P; Eriksson, J; Lindner, M; Pereira, D; Pinho, LM;

Publication
Ada User Journal

Abstract
In an embedded system, functions often operate under different requirements. In the extreme, a failing safety critical function may cause collateral damage (and hence consider to be a system failure) while non critical functions affect only the quality of service. Approaches by partitioning the system's functions into sandboxes require virtualization mechanisms by the underlying platform and thus prohibit deployment to the bulk of microcontroller based systems. In this paper we discuss an alternative approach based on static semantic analysis performed directly on the system specification expressed in the form of an object oriented (00) model in the experimental language RTFM-lang. This would allow to (at compile time) to discriminate in between critical and non-critical functions, and assign these (by means of statically checkable typing rules) appropriate access rights. In particular, one can imagine dynamic memory allocations to be allowed only in non-critical functions, while on the other hand, direct interaction with the environment may be restricted to the critical parts. With respect to scheduling, a static task and resource configuration allows e.g. Stack Resource Policy (SRP) based approaches to be deployed. In this paper we discuss how this can be achieved in a mixed critical setting.

2014

Wind and solar integration with plug-in electric vehicles smart charging strategies

Authors
Villar, J; Diaz, CA; Gonzalez, P; Campos, FA;

Publication
International Conference on the European Energy Market, EEM

Abstract
Combining large penetration of Plug-in Electric Vehicles (PEVs) and generation from Renewable Energy Sources (RES) seems a promising solution for energy cost saving and emission reduction. Indeed, RES generation increases instability grid problems due to its intermittency and lack of correlation with final energy usage. But the energy storage of the PEVs connected to the grid, controlled with smart charging and generating strategies, can compensate these uncertainties: energy surplus at low demands and high RES production (strong wind or sunshine) can be returned from PEVs to the grid at larger demand periods, and even provide regulation services. This paper analyses the combined impact of PEVs and RES penetration in the current Spanish power system with a detailed hydro-thermal Unit Commitment (UC) model for energy and reserve. Different charging strategies (from plug-and-charge to V2G with regulation) and wind and solar power penetration are tested with a full year simulation with weekly water management. Simulations show how PEVs smart charging strategies adapt PEVs operation to the existing generation structure, contributing efficiently to higher RES penetration rates, decreasing emissions and system operation costs. © 2014 IEEE.

2014

Evaluation of the Spoilage of Raw Chicken Breast Fillets Using Fourier Transform Infrared Spectroscopy in Tandem with Chemometrics

Authors
Vasconcelos, H; Saraiva, C; de Almeida, JMMM;

Publication
FOOD AND BIOPROCESS TECHNOLOGY

Abstract
The aim of this work was to evaluate the potential of Fourier transform infrared (FTIR) spectroscopy as a rapid and accurate technique to detect and predict the onset of spoilage in fresh chicken breast fillets stored at 3, 8, and 30 A degrees C. Chicken breasts were excised from carcasses at 6 h post-mortem; cut in fillets; packed in air; stored at 3, 8, and 30 A(0)C; and periodically examined for FTIR, pH, microbiological analysis, and sensory assessment of freshness. Partial least squares regression allowed estimations of total viable counts (TVC), lactic acid bacteria (LAB), Pseudomonas spp., Brochothrix thermosphacta, Enterobacteriaceae counts and pH, based on FTIR spectral data. Analysis of an external set of samples allowed the evaluation of the predictability of the method. The correlation coefficients (R-2) for prediction were 0.798, 0.832, 0.789, 0.810, 0.857, and 0.880, and the room mean square error of prediction were 0.789, 0.658, 0.715, 0.701, 0.756 log cfu g(-1) and 0.479 for TVC, LAB, Pseudomonas spp., B. thermosphacta, Enterobacteriaceae, and pH, respectively. The spectroscopic variables that can be linked and used by the models to predict the spoilage/freshness of the samples, pH, and microbial counts were the absorbency values of 375 wave numbers from 1,700 to 950 cm(-1). A principal component analysis led to the conclusion that the wave numbers that ranges from 1,408 to 1,370 cm(-1) and from 1,320 to 1,305 cm(-1) are strongly connected to changes during spoilage. These wave numbers are linked to amides and amines and may be considered potential wave numbers associated with the biochemical changes during spoilage. Discriminant analysis of spectral data was successfully applied to support sensory data and to accurately bound samples freshness. According to the results presented, it is possible to conclude that FTIR spectroscopy can be used as a reliable, accurate, and fast method for real time freshness evaluation of chicken breast fillets during storage.

2014

A Transceiver for E-Textile Body-Area-Networks

Authors
Carvalho, JG; da Silva, JM;

Publication
2014 IEEE INTERNATIONAL SYMPOSIUM ON MEDICAL MEASUREMENTS AND APPLICATIONS (MEMEA)

Abstract
A transceiver for single-line communication among sensor nodes of a body-area network is presented. It is meant to operate on a mesh like network where nodes are interconnected by two conducting-textile lines, which provide both power and communication features. The textile conductors are sewn directly to the garment in order to enhance user's mobility and comfort. For the same reason, a single battery placed in a central processing module is used to supply all sensor nodes. A low-dropout voltage regulator supplied from the transmission-line via a low pass filter ensures in each node the respective 3 V DC power supply. Power-line-communication is performed using a binary phase shift keying modulation process over a non-zero direct current line voltage at a 10 Mbps rate. The transceiver includes also line-fault testing to detect hazards which are likely to occur due to the stress applied to the conductive yarns.

2014

Computing with a full memory: catalytic space

Authors
Buhrman, H; Cleve, R; Koucký, M; Loff, B; Speelman, F;

Publication
Symposium on Theory of Computing, STOC 2014, New York, NY, USA, May 31 - June 03, 2014

Abstract
We define the notion of a catalytic-space computation. This is a computation that has a small amount of clean space available and is equipped with additional auxiliary space, with the caveat that the additional space is initially in an arbitrary, possibly incompressible, state and must be returned to this state when the computation is finished. We show that the extra space can be used in a nontrivial way, to compute uniform TC1-circuits with just a logarithmic amount of clean space. The extra space thus works analogously to a catalyst in a chemical reaction. TC1-circuits can compute for example the determinant of a matrix, which is not known to be computable in logspace. In order to obtain our results we study an algebraic model of computation, a variant of straight-line programs. We employ register machines with input registers x1, : : :, xn and work registers r1, : : :, rm. The instructions available are of the form ri?ri±u×?, with u, ? registers (distinct from ri) or constants. We wish to compute a function f(x1, : : :, xn) through a sequence of such instructions. The working registers have some arbitrary initial value ri = ti, and they may be altered throughout the computation, but by the end all registers must be returned to their initial value ti, except for, say, r1 which must hold t1 + f(x 1, : : :, xn). We show that all of Valiant's class VP, and more, can be computed in this model. This significantly extends the framework and techniques of Ben-Or and Cleve [6]. © 2014 ACM.

2014

Consolidation of qualitative studies in health research

Authors
de Souza, DN; Costa, AP; de Souza, FN; Reis, LP;

Publication
REVISTA DA ESCOLA DE ENFERMAGEM DA USP

Abstract

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