25,253 research outputs found

    COST Action IC 1402 ArVI: Runtime Verification Beyond Monitoring -- Activity Report of Working Group 1

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    This report presents the activities of the first working group of the COST Action ArVI, Runtime Verification beyond Monitoring. The report aims to provide an overview of some of the major core aspects involved in Runtime Verification. Runtime Verification is the field of research dedicated to the analysis of system executions. It is often seen as a discipline that studies how a system run satisfies or violates correctness properties. The report exposes a taxonomy of Runtime Verification (RV) presenting the terminology involved with the main concepts of the field. The report also develops the concept of instrumentation, the various ways to instrument systems, and the fundamental role of instrumentation in designing an RV framework. We also discuss how RV interplays with other verification techniques such as model-checking, deductive verification, model learning, testing, and runtime assertion checking. Finally, we propose challenges in monitoring quantitative and statistical data beyond detecting property violation

    Experimenting with independent and-parallel prolog using standard prolog

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    This paper presents an approximation to the study of parallel systems using sequential tools. The Independent And-parallelism in Prolog is an example of parallel processing paradigm in the framework of logic programming, and implementations like <fc-Prolog uncover the potential performance of parallel processing. But this potential can also be explored using only sequential systems. Being the spirit of this paper to show how this can be done with a standard system, only standard Prolog will be used in the implementations included. Such implementations include tests for parallelism in And-Prolog, a correctnesschecking meta-interpreter of <fc-Prolog and a simulator of parallel execution for <fc-Prolog

    Checking-in on Network Functions

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    When programming network functions, changes within a packet tend to have consequences---side effects which must be accounted for by network programmers or administrators via arbitrary logic and an innate understanding of dependencies. Examples of this include updating checksums when a packet's contents has been modified or adjusting a payload length field of a IPv6 header if another header is added or updated within a packet. While static-typing captures interface specifications and how packet contents should behave, it does not enforce precise invariants around runtime dependencies like the examples above. Instead, during the design phase of network functions, programmers should be given an easier way to specify checks up front, all without having to account for and keep track of these consequences at each and every step during the development cycle. In keeping with this view, we present a unique approach for adding and generating both static checks and dynamic contracts for specifying and checking packet processing operations. We develop our technique within an existing framework called NetBricks and demonstrate how our approach simplifies and checks common dependent packet and header processing logic that other systems take for granted, all without adding much overhead during development.Comment: ANRW 2019 ~ https://irtf.org/anrw/2019/program.htm

    What Did Slaves Wear? Textile Regimes In The French Caribbean

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    This study of the dress of enslaved men and women in the French Antilles is based on a critical examination of written and pictorial sources. Analyzing work clothes, by law masters’ responsibility, and festive apparel, which slaves themselves procured, the article focuses on the possibilities and limits of subordinate populations’ innovation in material culture. With comparisons to sartorial practices of enslaved people and other groups in the Caribbean and in the larger world, the paper addresses issues in the history of consumption and of the Atlantic basin in the seventeenth and eighteenth centuries, arguing that both standardization and diversification were fundamental features of early modern globalization

    Separation kernel robustness testing : the xtratum case study

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    With time and space partitioned architectures becoming increasingly appealing to the European space sector, the dependability of separation kernel technology is a key factor to its applicability in European Space Agency projects. This paper explores the potential of the data type fault model, which injects faults through the Application Program Interface, in separation kernel robustness testing. This fault injection methodology has been tailored to investigate its relevance in uncovering vulnerabilities within separation kernels and potentially contributing towards fault removal campaigns within this domain. This is demonstrated through a robustness testing case study of the XtratuM separation kernel for SPARC LEON3 processors. The robustness campaign exposed a number of vulnerabilities in XtratuM, exhibiting the potential benefits of using such a methodology for the robustness assessment of separation kernels.peer-reviewe

    Black Holes on FIRE: Stellar Feedback Limits Early Feeding of Galactic Nuclei

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    We introduce massive black holes (BHs) in the Feedback In Realistic Environments project and perform high-resolution cosmological hydrodynamic simulations of quasar-mass halos (Mhalo(z=2)1012.5MM_{\rm halo}(z=2) \approx 10^{12.5}\,\rm{M}_{\odot}) down to z=1z=1. These simulations model stellar feedback by supernovae, stellar winds, and radiation, and BH growth using a gravitational torque-based prescription tied to resolved properties of galactic nuclei. We do not include BH feedback. We show that early BH growth occurs through short (1\lesssim 1\,Myr) accretion episodes that can reach or even exceed the Eddington rate. In this regime, BH growth is limited by bursty stellar feedback continuously evacuating gas from galactic nuclei, and BHs remain under-massive relative to the local MBHM_{\rm BH}-MbulgeM_{\rm bulge} relation. BH growth is more efficient at later times, when the nuclear stellar potential retains a significant gas reservoir, star formation becomes less bursty, and galaxies settle into a more ordered state, with BHs rapidly converging onto the scaling relation when the host reaches Mbulge1010MM_{\rm bulge} \sim 10^{10}\,\rm{M}_{\odot}. Our results are not sensitive to the details of the accretion model so long as BH growth is tied to the gas content within 100\sim 100\,pc of the BH. Our simulations imply that bursty stellar feedback has strong implications for BH and AGN demographics, especially in the early Universe and for low-mass galaxies.Comment: 5 pages, 3 figures, submitted to MNRA

    Developments Under the Freedom of Information Act—1979

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