Execution time distributions in embedded safety-critical systems using extreme value theory

Several techniques have been proposed to upper-bound the worst-case execution time behaviour of programs in the domain of critical real-time embedded systems. These computing systems have strong requirements regarding the guarantees that the longest execution time a program can take is bounded. Some of those techniques use extreme value theory (EVT) as their main prediction method. In this paper, EVT is used to estimate a high quantile for different types of execution time distributions observed for a set of representative programs for the analysis of automotive applications. A major challenge appears when the dataset seems to be heavy tailed, because this contradicts the previous assumption of embedded safety-critical systems. A methodology based on the coefficient of variation is introduced for a threshold selection algorithm to determine the point above which the distribution can be considered generalised Pareto distribution. This methodology also provides an estimation of the extreme value index and high quantile estimates. We have applied these methods to execution time observations collected from the execution of 16 representative automotive benchmarks to predict an upper-bound to the maximum execution time of this program. Several comparisons with alternative approaches are discussed.The research leading to these results has received funding from the European Community’s Seventh Framework Programme [FP7/2007-2013] under the PROXIMA Project (grant agreement 611085). This study was also partially supported by the Spanish Ministry of Science and Innovation under grants MTM2012-31118 (2013-2015) and TIN2015-65316-P. Jaume Abella is partially supported by the Ministry of Economy and Competitiveness under Ramon y Cajal postdoctoral fellowship number RYC-2013- 14717.Peer ReviewedPostprint (author's final draft

A PESA-AGB study

This study uses a MCDA tool to analyse and improve Spanish airports performance and efficiency. Thus, a holistic study using MACBETH (with PESA-AGB) is used. This study has never been applied before in Spanish airports. Firstly, a literature review related to this study keywords is conducted, as well as about benchmarking concept applied specifically to airports. Secondly, several methodologies in used to benchmark airports are reviewed and compared. Thirdly, airport performance and efficiency issues are addressed and described. Finally, the MCDA-MACBETH (with PESA-AGB) tool is applied to 4 Spanish airports. Spanish airports belonging to AENA transported 263,753,406 passengers in 2018 with an increase compared to 2017 of 5.8%. General data enables to conclude that Spanish air transportation system is growing annually and hence there is the need to improve airports performance and efficiency, also to maintain the high levels of quality to address the growing demand. Spanish air transportation system is growing annually and is it upmost important to maintain high levels of quality to address such demand. Through this study, performance and efficiency improvements are seek within several airport key areas such as Safety and Security, Quality Service, Productivity and Effectiveness, Financial and Environment. As far as known, this study has never been applied before in Spanish airports.info:eu-repo/semantics/publishedVersio

Measurement-Based Worst-Case Execution Time Estimation Using the Coefficient of Variation

Extreme Value Theory (EVT) has been historically used in domains such as finance and hydrology to model worst-case events (e.g., major stock market incidences). EVT takes as input a sample of the distribution of the variable to model and fits the tail of that sample to either the Generalised Extreme Value (GEV) or the Generalised Pareto Distribution (GPD). Recently, EVT has become popular in real-time systems to derive worst-case execution time (WCET) estimates of programs. However, the application of EVT is not straightforward and requires a detailed analysis of, and customisation for, the particular problem at hand. In this article, we tailor the application of EVT to timing analysis. To that end, (1) we analyse the response time of different hardware resources (e.g., cache memories) and identify those that may lead to radically different types of execution time distributions. (2) We show that one of these distributions, known as mixture distribution, causes problems in the use of EVT. In particular, mixture distributions challenge not only properly selecting GEV/GPD parameters (i.e., location, scale and shape) but also determining the size of the sample to ensure that enough tail values are passed to EVT and that only tail values are used by EVT to fit GEV/GPD. Failing to select these parameters has a negative impact on the quality of the derived WCET estimates. We tackle these problems, by (3) proposing Measurement-Based Probabilistic Timing Analysis using the Coefficient of Variation (MBPTA-CV), a new mixture-distribution aware, WCET-suited MBPTA method that builds on recent EVT developments in other fields (e.g., finance) to automatically select the distribution parameters that best fit the maxima of the observed execution times. Our results on a simulation environment and a real board show that MBPTA-CV produces high-quality WCET estimates.The research leading to these results has received funding from the European Community’s FP7 [FP7/2007- 2013] under the PROXIMA Project (www.proxima-project.eu), grant 611085. This work has also been par- tially supported by the Spanish Ministry of Science and Innovation under grant TIN2015-65316-P and the HiPEAC Network of Excellence. Jaume Abella was partially supported by the Ministry of Economy and Competitiveness under Ramon y Cajal postdoctoral fellowship RYC-2013-14717.Peer ReviewedPostprint (author's final draft

Movements of a Juvenile Crowned Eagle (\u3cem\u3eHarpyhaliaetus Coronatus\u3c/em\u3e) Tracked by Satellite Telemetry in Central Argentina

Background: A juvenile Crowned Eagle was tagged at its nest with a satellite transmitter. The Crowned Eagle (Harpyhaliaetus coronatus) is one of the most unknown raptor species from the American continent. Their current distribution ranges from central Brazil to central Argentina, with a total population of 350–1500 individuals across this large area, being thus largely fragmented. Results: During the three years of tracking the bird concentrated its movements in a range spanning for 12845 km2, but concentrating mainly in four smaller areas accounting for 3073 km2. The locations were recorded mainly over shrubland habitats (86.5%), whereas other habitats used were different types of mosaics that included cropland and natural vegetation (forest, shrubland or grassland) close to wetlands. Conclusions: The home-range estimated for this individual during the whole period was 12845 km2 (according to 95% fixed kernel). However, the bird concentrated most of its movements in smaller areas (as defined above), that accounted for a total of 3073 km2 (50% fixed kernel). During these three years, most of the locations of the juvenile solitary Crowned Eagle were recorded over shrubland habitats (86.5% of the locations). Understanding in a more detailed way the juvenile ranging behaviour and habitat preferences would be of great importance for the conservation of the Crowned Eagle

Production and high throughput quantification of fucoxanthin and lipids in Tisochrysis lutea using single-cell fluorescence

This work aimed to investigate the accumulation of fucoxanthin and lipids in Tisochrysis lutea during growth (N+) and nitrogen-starvation (N−) and to correlate these products with single-cell emissions using fluorescence-activated cell sorting (FACS). Fucoxanthin content decreased 52.94% from N+ to N− in batch cultivation; increased 40.53% as dilution rate changed from 0.16 to 0.55 d−1 in continuous cultivation. Total lipids (N−) were constant (~250 mg/g), but the abundance of neutral lipids increased from 4.87% to 40.63%. Nile red can stain both polar and neutral lipids. However, in vivo, this differentiation is limited due to an overlapping of signals between 600 and 660 nm, caused by neutral lipids concentrations above 3.48% (W/W). Chlorophyll autofluorescence (720 nm) was reported for the first time as a proxy for fucoxanthin (R2 = 0.90) and polar lipids (R2 = 0.98). FACS can be used in high throughput quantification of pigments and lipids and to select and sort cells with high-fucoxanthin/lipids.publishedVersionPaid Open Acces

Model performance of partial least squares in utilizing the visible spectroscopy data for estimation of algal biomass in a photobioreactor

[EN] Spectroscopy technology and statistical methods (Partial Least Squares) have been integrated to develop a model that allows estimating the microalgal biomass in a photobioreactor. The model employing PLS combines the absorption spectrum measurements in the visible range (400-750 nm) with a microalgae cell density in a water sample. First, a calibration model was constructed using a calibration data set, and then, the predictive capacity of the model was determined by cross validation. Finally, an external validation of the predictive performance of the model was carried out with an independent data set. To test the accuracy of the model it was applied to different culture conditions yielding a predictive capacity of 96.7 %. The results achieved are highly satisfactory due to the good lineal adjustment between observed cell densities vs. predicted ones obtained. According to the results obtained, the application of the model is a useful tool for the management and the decision-making process when operating a photobioreactor. Moreover, this model may boost the real-time measurements and may represent a previous step for further technical development in the ¿internet of things¿ applied to the management of the photobioreactor.This research project has been supported by the Spanish Research Foundation (CICYT, projects CTM2011-28595-C02-01 and CTM2011-28595-C02-02), whose support is gratefully acknowledged.Martínez-Guijarro, MR.; Paches Giner, MAV.; Ferrer, J.; Seco Torrecillas, A. (2018). Model performance of partial least squares in utilizing the visible spectroscopy data for estimation of algal biomass in a photobioreactor. Environmental Technology & Innovation. 10:122-131. https://doi.org/10.1016/j.eti.2018.01.005S1221311

Comparison between the Psychopathy Checklist-Revised and the Comprehensive Assessment of Psychopathic Personality in a representative sample of Spanish prison inmates

In the field of psychopathy, there is an ongoing debate about the core traits that define the disorder, and that therefore must be present to some extent in all psychopaths. The main controversy of this debate concerns criminal behaviour, as some researchers consider it a defining trait, while others disagree. Using a representative sample of 204 Spanish convicted inmates incarcerated at the Pereiro de Aguiar Penitentiary in Ourense, Spain, we tested two competing models, the Psychopathy Checklist-Revised (PCL-R), which includes criminal behaviour items, versus the Comprehensive Assessment of Psychopathic Personality (CAPP), which does not. We used two different PCL-R models, one that includes criminal items and another that does not. PCL-R factors, facets, and testlets from both models and CAPP dimensions were correlated and compared. Two different PCL-R cut-off scores, 25 or more and 30 or more, were used for the analysis. Overall, a strong correlation was found between PCL-R and CAPP scores in the whole sample, but as scores increased and inmates became more psychopathic, the correlations weakened. All these data indicate that psychopathy, understood to mean having high scores on the PCL-R and CAPP, is a multidimensional entity, and inmates can develop the disorder and then receive the diagnosis through different dimensions. The CAPP domains showed better correlations when compared with the PCL-R factors from both models, showing that an instrument for the assessment of psychopathy without a criminal dimension is valuable for clinical assessment and research purposes.publishedVersio

Suport a les famílies en la primera infància

En el treball es revisen una sèrie de conceptes i estudis relacionats amb la família, la parentalitat, el context familiar i l’atenció i suport a les famílies, atenent al moment actual i els canvis sociodemogràfics. També es revisen alguns programes existents en el context europeu, en el nostre país i a la nostra comunitat posant de relleu el buit existent quant a l’atenció a la parentalitat de les famílies immerses en contextos vulnerables i que presenta dificultats en l’exercici de la parentalitat i l’atenció als infants. La tesi segueix una metodologia qualitativa, a través de l’estudi de cas. Així, s’analitza un programa socioeducatiu que treballa amb infants entre 0 i 5 anys, i les seves famílies que es troben immerses en contextos vulnerables. L’estudi de cas permet descriure el procés d’implementació, identificar i analitzar les característiques principals en relació al seu funcionament, i relatar la consolidació del program

Sporadic Creutzfeldt-Jakob disease with glial PrPRes nuclear and perinuclear immunoreactivity

Proteinase K-resistant prion protein (PrPRes ) nuclear and perinuclear immunoreactivity in oligodendrocytes of the frontal cortex is found in one case of otherwise typical sporadic Creutzfeldt-Jakob disease (sCJD) type VV2a. The PrP nature of the inclusions is validated with several anti-PrP antibodies directed to amino acids 130-160 (12F10), 109-112 (3F4), 97-102 (8G8) and the octarepeat region (amino acids 59-89: SAF32). Cellular identification and subcellular localization were evaluated with double- and triple-labeling immunofluorescence and confocal microscopy using antibodies against PrP, glial markers, and histone H3. Based on review of the literature and our own experience, this is a very odd situation that deserves further validation in other cases. Keywords: Creutzfeldt-Jakob disease; astrocytes; oligodendrocytes; prion