A Generic Annotation Inference Algorithm for the Safety Certification of Automatically Generated Code

Code generators for realistic application domains are not directly verifiable in practice. In the certifiable code generation approach the generator is extended to generate logical annotations (i.e., pre- and postconditions and loop invariants) along with the programs, allowing fully automated program proofs of different safety properties. However, this requires access to the generator sources, and remains difficult to implement and maintain because the annotations are cross-cutting concerns, both on the object-level (i.e., in the generated code) and on the meta-level (i.e., in the generator). Here we describe a new generic post-generation annotation inference algorithm that circumvents these problems. We exploit the fact that the output of a code generator is highly idiomatic, so that patterns can be used to describe all code constructs that require annotations. The patterns are specific to the idioms of the targeted code generator and to the safety property to be shown, but the algorithm itself remains generic. It is based on a pattern matcher used to identify instances of the idioms and build a property-specific abstracted control flow graph, and a graph traversal that follows the paths from the use nodes backwards to all corresponding definitions, annotating the statements along these paths. This core is instantiated for two generators and successfully applied to automatically certify initialization safety for a range of generated programs

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Low energy proton irradiated solar cells using sun simulato

Race, diversity and criminal justice in Canada:a view from the UK

ABSTRACT This article examines the way in which those employed in the Canadia

Charged Particle Radiation Damage in Semiconductors, I- Experimental Proton Irradiation of Solar Cells

Proton irradiation of solar cell

Deriving Safety Cases for the Formal Safety Certification of Automatically Generated Code

We present an approach to systematically derive safety cases for automatically generated code from information collected during a formal, Hoare-style safety certification of the code. This safety case makes explicit the formal and informal reasoning principles, and reveals the top-level assumptions and external dependencies that must be taken into account; however, the evidence still comes from the formal safety proofs. It uses a generic goal-based argument that is instantiated with respect to the certified safety property (i.e., safety claims) and the program. This will be combined with a complementary safety case that argues the safety of the framework itself, in particular the correctness of the Hoare rules with respect to the safety property and the trustworthiness of the certification system and its individual components

The Lick AGN Monitoring Project: Velocity-Delay Maps from the Maximum-Entropy Method for Arp 151

We present velocity-delay maps for optical H I, He I, and He II recombination lines in Arp 151, recovered by fitting a reverberation model to spectrophotometric monitoring data using the maximum-entropy method. H I response is detected over the range 0-15 days, with the response confined within the virial envelope. The Balmer-line maps have similar morphologies but exhibit radial stratification, with progressively longer delays for Hgamma to Hbeta to Halpha. The He I and He II response is confined within 1-2 days. There is a deficit of prompt response in the Balmer-line cores but strong prompt response in the red wings. Comparison with simple models identifies two classes that reproduce these features: freefalling gas, and a half-illuminated disk with a hotspot at small radius on the receding lune. Symmetrically illuminated models with gas orbiting in an inclined disk or an isotropic distribution of randomly inclined circular orbits can reproduce the virial structure but not the observed asymmetry. Radial outflows are also largely ruled out by the observed asymmetry. A warped-disk geometry provides a physically plausible mechanism for the asymmetric illumination and hotspot features. Simple estimates show that a disk in the broad-line region of Arp 151 could be unstable to warping induced by radiation pressure. Our results demonstrate the potential power of detailed modeling combined with monitoring campaigns at higher cadence to characterize the gas kinematics and physical processes that give rise to the broad emission lines in active galactic nuclei.Comment: 7 pages, 5 figures, accepted for publication in the Astrophysical Journal Letter

Biases in the Quasar Mass-Luminosity Plane

We find that the recently reported departure from the Eddington luminosity limit for the highest quasar black hole masses at a given redshift is an artifact due to biases in black hole mass measurements. This sub-Eddington boundary (with non-unity slope) in the quasar mass-luminosity plane was initially reported by Steinhardt & Elvis (2010a) using the FWHM-based black hole mass catalogue of Shen et al. (2008). However, the significance of the boundary is reduced when the FWHM-based mass-scaling relationship is recalibrated following Wang et al. (2009) and using the most updated reverberation mapping estimates of black hole masses. Furthermore, this boundary is not seen using mass estimates based on the line dispersion of the same quasars' MgII emission lines. Thus, the initial report of a sub-Eddington boundary with non-unity slope was due to biases in estimating masses using the FWHM of a fit of one or two Gaussians to quasar MgII emission lines. We provide evidence that using the line dispersion of the MgII line produces less biased black hole mass estimates.Comment: 11 pages, 10 figures, Accepted for publication in MNRA

Beyond Basic Needs: Social Support and Structure for Successful Offender Reentry

Barriers to successful reentry have long been identified as impeding an offender’s ability to successfully reenter society upon release from incarceration. As a result, research has long examined what shared obstacles the majority of offenders often face upon reentering society. Much of the research identifies factors such as poor education, obtaining/maintaining employment, stable housing, and transportation as common barriers to successful reentry. By using in-depth interviews with ex-offenders deemed as successful that were conducted by two respective non-profit agencies, the present study explores what significant requirements, if any, successful offenders perceive to need and/or have experienced as lacking while attempting to successfully reenter society. Findings from this study highlight that many of the research- identified needs are not major barriers because they are often provided for by various non-profit agencies. Furthermore, successful ex-offenders overwhelmingly identify poor social support as a major barrier that oftentimes remains neglected in government and non-profit organizational programming