Continuity properties of a factor of Markov chains

Starting from a Markov chain with a finite alphabet, we consider the chain obtained when all but one symbol are undistinguishable for the practitioner. We study necessary and sufficient conditions for this chain to have continuous transition probabilities with respect to the past

A first look at RISC-V virtualization from an embedded systems perspective

This article describes the first public implementation and evaluation of the latest version of the RISC-V hypervisor extension (H-extension v0.6.1) specification in a Rocket chip core. To perform a meaningful evaluation for modern multi-core embedded and mixedcriticality systems, we have ported Bao, an open-source static partitioning hypervisor, to RISC-V. We have also extended the RISC-V platformlevel interrupt controller (PLIC) to enable direct guest interrupt injection with low and deterministic latency and we have enhanced the timer infrastructure to avoid trap and emulation overheads. Experiments were carried out in FireSim, a cycle-accurate, FPGA-accelerated simulator, and the system was also successfully deployed and tested in a Zynq UltraScale+ MPSoC ZCU104. Our hardware implementation was opensourced and is currently in use by the RISC-V community towards the ratification of the H-extension specification.This work has been supported by FCT - undação para a Ciência e a Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. This work has also been supported by FCT within the PhD Scholarship Project Scope: SFRH/BD/138660/2018

Os efeitos da licença maternidade sobre o salário e o emprego da mulher no Brasil

This paper aims to estimate the effects of maternity leave legislation in women’s wages and employment in Brazil. We analyze the impact of an increase in the leave period, which was raised from 12 weeks to 120 days, as prescribed by the Federal Constitution of 1998. According to the theoretical literature, the effect of the legislation is ambiguous. One should expect that the leave would have negative effects on labor demand to the extent that it raises labor costs. On the other hand, the legislation is expected to increase labor supply and can have positive effects on wages if it avoids that women leave the labor market each time they have a child, therefore increasing the firm-specific human capital of these workers. We use a simple difference-indifferences methodology applied to data from Pesquisa Mensal de Emprego between 1986 and 1991. We compare the changes in wages and employment between the periods before and after the 1988 Constitution of women in fertile ages (our treatment group) with those of two control groups: men at the same ages and women in non-fertile ages. The results show that the leave increase had no significant impact on wages. We also find no signs that the leave increase raised women’s retention in the labor market, even in the case of the more educated female workers. The results also show insignificant impact in women’s employment.licença maternidade, salário da mulher, emprego da mulher

Questões práticas sobre o acordo de não persecução penal

- Divulgação dos SUMÁRIOS das obras recentemente incorporadas ao acervo da Biblioteca Ministro Oscar Saraiva do STJ. Em respeito à Lei de Direitos Autorais, não disponibilizamos a obra na íntegra.- Localização na estante: 343.123(81) C331

Probing Stellar Populations and Interstellar Medium in Early-Type Central Galaxies

In this study, we analyse the characteristics of stellar populations and the interstellar medium (ISM) in 15,107 early-type central galaxies from the SPIDER survey. Using optical spectra from the Sloan Digital Sky Survey (SDSS), we investigate stellar age (Age), metallicity ($Z$), visual extinction ($A_{\rm V}$), and H$\alpha$ equivalent width (EWH$\alpha$) to understand the evolution of the baryonic content in these galaxies. Our analysis explores the relationship between these properties and central velocity dispersion ($\sigma$) and halo mass ($M_{\rm halo}$) for isolated centrals (ICs) and group centrals (GCs). Our results confirm that both ICs and GCs' stellar populations and gas properties are mainly influenced by $\sigma$, with $M_{\rm halo}$ playing a secondary role. Higher $\sigma$ values correspond to older, more metal-rich stellar populations in both ICs and GCs. Moreover, fixed $\sigma$ values we observe younger Ages at higher values of $M_{\rm halo}$, a consistent trend in both ICs and GCs. Furthermore, we investigate the ionisation source of the warm gas and propose a scenario where the properties of ionised gas are shaped by a combination of cooling within the intra-cluster medium (ICM) and feedback from Active Galactic Nuclei (AGN) assuming a Bondi accretion regime. We observe inherent differences between ICs and GCs, suggesting that the ratio between AGN kinetic power and ICM thermal energy influences EWH$\alpha$ in ICs. Meanwhile, gas deposition in GCs appears to involve a more complex interplay beyond a singular AGN-ICM interaction.Comment: 14 pages, 11 figures, accepted for publication in the MNRA

Concerns about Cybersecurity: The Implications of the use of ICT for Citizens and Companies

The widespread use of Information and Communication Technologies - ICT substantially increases the risks related to information security. In fact, due to the increase in the number and type of cyber attacks, Cybersecurity has become a growing concern in today's society. This phenomenon affects not only individual citizens, but also companies and even State entities. Despite the numerous advantages of this "digitalisation" of society, there are several risks, ranging from identity theft, scam emails or phone calls, online fraud, offensive material and child pornography, material promoting racial hatred or religious extremism, access to online services, email account hacking, online banking fraud, cyber extortion or malicious software. In order to determine the impact that cyber attacks have on society it is necessary to understand how people and companies use ICTs, such as social networks, the information they share, their privacy concerns, or the use of electronic services such as online payments or the cloud. This study becomes central not only to try to prevent/minimise risks, showing what has been done in this area, but more importantly, the way forward to try to prevent or minimise possible risks in the future.info:eu-repo/semantics/publishedVersio

ReZone: disarming TrustZone with TEE privilege reduction

In TrustZone-assisted TEEs, the trusted OS has unrestricted access to both secure and normal world memory. Unfortunately, this architectural limitation has opened an aisle of exploration for attackers, which have demonstrated how to leverage a chain of exploits to hijack the trusted OS and gain full control of the system, targeting (i) the rich execution environment (REE), (ii) all trusted applications (TAs), and (iii) the secure monitor. In this paper, we propose REZONE. The main novelty behind REZONE design relies on leveraging TrustZone-agnostic hardware primitives available on commercially off-the-shelf (COTS) platforms to restrict the privileges of the trusted OS. With REZONE, a monolithic TEE is restructured and partitioned into multiple sandboxed domains named zones, which have only access to private resources. We have fully implemented REZONE for the i.MX 8MQuad EVK and integrated it with Android OS and OP-TEE. We extensively evaluated REZONE using microbenchmarks and real-world applications. REZONE can sustain popular applications like DRM-protected video encoding with acceptable performance overheads. We have surveyed 80 CVE vulnerability reports and estimate that REZONE could mitigate 86.84% of them.We thank our shepherd Aastha Mehta and the anonymous reviewers for their comments and suggestions. This work was supported by national funds through Centro ALGORITMI / Universidade do Minho, Instituto Superior Técnico / Universidade de Lisboa, and FCT under project UIDB/50021/2020 and UIDB/00319/2020. David Cerdeira was supported by FCT grant SFRH/BD/146231/2019