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

Liderazgo y empoderamiento en entornos universitarios

El liderazgo y el empoderamiento ocupan, desde la década de los noventa, un lugar destacado y transversal en la agenda política no solo de la Unión Europea y España, sino también en la política universitaria española. Sin embargo, diferentes informes sobre la posición de las mujeres en la Universidad ponen de manifiesto la persistencia de desigualdades y desequilibrios en el acceso, en la trayectoria profesional y en su presencia en los órganos de representación. En el plano de la realidad, el liderazgo mantiene una estrecha y compleja relación con procesos y realidades afines tales como la concepción del poder y la legitimidad, autoridad y el prestigio con el que se identifica a quien lidera. En esta compleja relación podemos identificar algunos elementos idiosincráticos del proceso de empoderamiento de las mujeres universitarias desde su consideración de ‘recién llegadas’. Los avances, retos, ambigüedades y tensiones que introduce el desarrollo de políticas de igualdad en los entornos universitarios en relación con los proceso de liderazgo y empoderamiento (individual y colectivo) se ejemplifican tomando en consideración los hallazgos arrojados por la investigación desarrollada en la universidad española, en concreto, en las universidades valencianas (Escolano, 2006) y, más recientemente, en la Universidad de Alicante (Rodríguez, González y Albert, 2014)

The direct rebound effect for two income groups : The case of Paraguay

Altres ajuts: Acord transformatiu CRUE-CSICAltres ajuts: Becas Don Carlos Antonio López (BECAL) (106/2017) ; Beatriu de Pinós postdoctoral program of the Government of Catalonia's Secretariat for Universities and Research of the Ministry of Economy and Knowledge.We estimate the direct rebound effect (DRE) for all energy services requiring electricity for their provision in Paraguayan households. Using recent panel data from 2001 to 2017, we estimate the magnitude of the DRE at the province and municipality levels. Because we estimate the DRE through the own-price elasticity of electricity demand, we not only provide the first empirical evidence of the DRE for Paraguay, a developing country, but also update the study of Paraguay's residential electricity demand. Our findings suggest a positive DRE emerges after an improvement in energy efficiency, but the magnitude of the DRE does not completely reduce the resulting energy savings. We find a lower DRE in low-income households, which may be explained by two factors: electricity is not the main source of energy for most low-income households, and most clandestine electricity connections are from low-income households. Paraguay is one of the countries with the highest generation of electricity per capita through hydroelectric plants. However, this electricity supply does not match electricity consumption, especially in low-income households, because of distribution issues in relation to energy sources. We derive from our findings some policy measures to improve the situation

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

Catalogació i millora de vendes d'una llibreria

En aquest projecte s'ha desenvolupat un entorn web per la gestió de productes a la Llibreria Roca de Manresa que permet la venda en línia, a més d'un entorn on els possibles clients poden consultar tot el catàleg d'ofertes que ofereix l'empresa. Així la botiga, a més de poder controlar els seus productes de forma més eficient, els podrà servir a molta més gent un cop l'entorn estigui preparat.En este proyecto se ha desarrollado un entorno web para la gestión de productos en la Librería Roca de Manresa que permite la venta en línea, ademas de un entorno donde los posibles clientes pueden concultar todo el catálogo de ofertas que ofrece la empresa. Así la tienda, además de poder controlar sus productos de forma más eficiente, los podrá servir a mucha más gente una vez el entorno esté preparado

Endurance or sprint interval exercise, & metformin treatment differently modify insulin-induced vasodilation in skeletal muscle arterioles of obese insulin resistant rats

A key contributor to insulin-mediated glucose uptake is insulin-induced vasodilation of skeletal muscle arterioles, which is impared with obesity and Type 2 diabetes (T2D). Abnormalities in the vascular reactivity to insulin can limit perfusion, and delivery of glucose and insulin to muscle tissue. In human patients with T2D, exercise improves insulin sensitivity and glucose uptake T2D. Furthermore, we have previously shown that daily exercise prevents impairments in insulin-induced vasodilation in OLETF rats. However, the efficacy of exercise interventions which utilize different muscle recruitment patterns (i.e. aerobic vs. sprint training) to ameliorate or reverse impairments in microvascular insulin reactivity has not been elucidated. The current ADA standard of care for T2D is treatment with metformin in combination with a diet and exercise program. Therefore, we studied the effects of endurance exercise and interval sprint training with and without metformin on the vasoreactivity to insulin in skeletal muscle arterioles from red and white muscles

The direct rebound effect of electricity energy services in spanish households : evidence from error correction model and system GMM estimates

We review the empirical literature concerning the magnitude of the direct rebound effect in households, ocusing on econometric studies, and analyze the theoretical and methodological aspects for the estimation of the direct rebound effect. We then estimate the magnitude of the direct rebound effect of households' electricity consumption in Spain. Using panel data from 2007 to 2016 for all the Spanish provinces, we estimate the short- and long-run direct rebound effects. In order to deal with cointegration of variables and to solve potential spurious relationships between them, we use a two-step Error Correction Model. We also estimate the dynamic model through a GMM system. The results indicate a direct rebound effect between 26% and 35% in the short- run and around 36% in the long-run. These findings suggest that, in Spain, energy efficiency policies with the aim of saving electricity consumption are significantly less effective without complementary measures to tackle the direct rebound effect. Moreover, one can expect a greater electricity savings response from households to price changes than to income or weather changes. We find a significant influence of other energy sources that appear to be complementary to electricity consumption according to our estimation

Beta 3 Adrenergic Receptor Activation Rescues Metabolic Dysfunction in Female Estrogen Receptor Alpha-Null Mice

Metabolic disease risk escalates following menopause. The mechanism is not fully known, but likely involves reduced signaling through estrogen receptor alpha (ERα), which is highly expressed in brown and white adipose tissue (BAT and WAT).Objective: Test the hypothesis that uncoupling protein (UCP1) activation mitigates metabolic dysfunction caused by loss of signaling through ERα.Methods: At 8 weeks of age, female ERα knock out (KO) and wild-type mice were housed at 28°C and fed a Western-style high-fat, high sucrose diet (HFD) or a normal low-fat chow diet (NC) for 10 weeks. During the final 2 weeks, they received daily injections of CL 316,256 (CL), a selective β3 adrenergic agonist, or vehicle control (CTRL), creating eight groups: WT-CTRL, WT-CL, KO-CTRL, and KO-CL on HFD or NC; n = 4–10/group.Results: ERαKO demonstrated exacerbated HFD-induced adiposity gain (P < 0.001) and insulin resistance (P = 0.006). CL treatment improved insulin sensitivity (P < 0.05) and normalized ERαKO-induced adiposity increase (P < 0.05). In both genotypes, CL increased resting energy expenditure (P < 0.05) and induced WAT beiging indicated by increased UCP1 protein in both perigonadal (PGAT) and subcutaneous (SQAT) depots. These effects were attenuated under HFD conditions (P < 0.05). In KO, CL reduced HFD energy consumption compared to CTRL (P < 0.05). Remarkably, CL increased WAT ERβ protein levels of both WT and KO (P < 0.001), revealing CL-mediated changes in estrogen signaling may have protective metabolic effects.Conclusion: CL completely restored metabolic dysfunction in ERαKO mice. Thus, UCP1 may be a therapeutic target for treating metabolic dysfunction following loss of estrogen receptor signaling

Double-cell superstructure and vacancy ordering in tensile-strained metallic thin films of P r0.50 C a0.50Co O3 on LaAl O3

The Pr-based cobaltate Pr0.5Ca0.5CoO3 (PCCO) presents in bulk form a singular simultaneous valence and spin-state transition that turns the metallic state into insulator, and displays a large and ultrafast photoresponse in the insulating phase. Epitaxial thin films of PCCO have been grown by deposition on LaAlO3(001) (LAO) substrate, chosen to minimize the mismatch with the film. The films grow epitaxially with two times the substrate periodicity (2a0×2a0×2a0) and the long perovskite axis perpendicular to the surface. We report a reduction of the structural symmetry from Pnma (bulk) to P212121 (film). The P212121 symmetry revealed by synchrotron x ray remains at low temperatures. These PCCO films are metallic, and ferromagnetic below TC=170K, confirming the stabilization of excited Co3+ spin states and the suppression of the concurrent Co spin-state, valence, and metal-insulator transitions. Z-contrast imaging and electron-energy-loss spectroscopy elemental maps reveal long-range ordered oxygen vacancy planes unexpectedly stacking parallel to the interface, in spite of the tensile character of the PCCO/LAO heterostructure. In contrast to the general tendency reported for strained La0.5Sr0.5CoO3-d (LSCO) films, we show that a nominal tensile strain can be also compatible with the presence of alternating O vacancy planes parallel to the interface, instead of perpendicular to it. That occurs thanks to the double cell of the film and the formation of the (1/2, 1/2, 1/2) superstructure studied in this work. These results expand the possibilities of controlling interfacial physical properties via engineering of ordered oxygen-defect structures in strongly correlated oxides

Eficiència energètica i consum de recursos : una estimació de l'efecte rebot a Catalunya

L'efecte rebot és aquell mecanisme a través del qual una millora de l'eficiència energètica no produeix el potencial estalvi d'energia esperat, o inclús pot fer que n'augmenti el consum. Això és degut a que una millora de l'eficiència energètica produeix un abaratiment del cost de proveir el servei energètic, que n'impulsa la demanda. Aquest treball realitza una revisió de la literatura existent sobre efecte rebot directe; analitza els principals aspectes teòrics i metodològics; i finalment estima, a partir de tècniques economètriques, la magnitud de l'efecte rebot directe per als serveis energètics que utilitzen energia elèctrica a les llars a Catalunya