32 research outputs found
Adversarial Authorship Attribution in Open-Source Projects
No full textOpen-source software is open to anyone by design, whether it is a community of developers, hackers or malicious users. Authors of open-source software typically hide their identity through nicknames and avatars. However, they have no protection against authorship attribution techniques that are able to create software author profiles just by analyzing software characteristics. In this paper we present an author imitation attack that allows to deceive current authorship attribution systems and mimic a coding style of a target developer. Withing this context we explore the potential of the existing attribution techniques to be deceived. Our results show that we are able to imitate the coding style of the developers based on the data collected from the popular source code repository, GitHub. To subvert author imitation attack, we propose a novel author obfuscation approach that allows us to hide the coding style of the author. Unlike existing obfuscation tools, this new obfuscation technique uses transformations that preserve code readability. We assess the effectiveness of our attacks on several datasets produced by actual developers from GitHub, and participants of the GoogleCodeJam competition. Throughout our experiments we show that the author hiding can be achieved by making sensible transformations which significantly reduce the likelihood of identifying the author’s style to 0% by current authorship attribution systems
The impact of a young radio galaxy: clues from the cosmic ray electron population
No full textIn the framework of hierarchical structure formation, active galactic nuclei (AGN) feedback shapes the galaxy luminosity function. Low luminosity, galaxy-scale double radio sources are ideal targets to investigate the interplay between AGN feedback and star formation. We use Very Large Array and BIMA millimetre-wave array observations to study the radio continuum emission of NGC 3801 between 1.4 and 112.4 GHz. We find a prominent spectral break at ~10 GHz, where the spectrum steepens as expected from cosmic ray electron (CRe) ageing. Using the equipartition magnetic field and fitting JP models locally, we create a spatially resolved map of the spectral age of the CRe population. The spectral age of τint = 2.0 ± 0.2 Myr agrees within a factor of 2 with the dynamical age of the expanding X-ray emitting shells. The spectral age varies only little across the lobes, requiring an effective mixing process of the CRe such as a convective backflow of magnetized plasma. The jet termination points have a slightly younger CRe spectral age, hinting at in situ CRe re-acceleration. Our findings support the scenario where the supersonically expanding radio lobes heat the interstellar medium (ISM) of NGC 3801 via shock waves, and, as their energy is comparable to the energy of the ISM, are clearly able to influence the galaxy's further evolution
Immigration Detention and Release Decisions in Canada: Development and Preliminary Validation of a Risk Assessment Tool for Frontline Officers
No full textImmigration detention systems face mounting pressure to demonstrate transparent and defensible decision-making practices amid growing ethical concerns. The Canada Border Services Agency (CBSA) has drawn particular scrutiny in this area, largely due to its partnerships with correctional agencies. Critics challenge CBSA's framework for placing noncitizens in these facilities, characterizing its risk assessment processes as opaque and arbitrary. To address these limitations, we developed the Immigration Risk Assessment for Detention (IRAD), an empirically informed tool designed to meet CBSA's multiple decision-making needs—from release on community-based alternatives to detention (ATDs) to security classification level within detention facilities. This dissertation presents research conducted across three co-authored articles, each representing a distinct phase in the IRAD’s development and preliminary validation. First, we surveyed 92 CBSA employees to gather their insights on immigration detention risk assessment. Second, we developed a 30-item numerical IRAD prototype by integrating our survey results with CBSA’s operational guidance and correctional risk assessment research. We then conducted a longitudinal retrospective validation of the IRAD prototype using 301 case files, which provided preliminary support for its use. The IRAD's Danger to Public and Unlikely to Appear domains showed good to excellent interrater reliability, and the latter domain predicted ATD violations with moderate accuracy. Concordance analyses revealed misalignments between client risk and CBSA's purportedly risk-based decisions. The IRAD and CBSA's current security classification tool also showed similar concordance with security classification decisions. Finally, we adapted the IRAD prototype for operational use, creating a 21-item structured professional judgement tool. We then explored the potential operational utility of this tool in a mixed prospective-retrospective pilot with CBSA employees. Though low officer engagement prevented robust evaluation, we found further evidence of misalignment between risk and decisions. A noise audit with client vignettes also revealed inconsistencies among officers during the risk identification, risk analysis, and decision-making processes for ATD determinations. As the IRAD consolidates CBSA's operational resources, our research suggests that decisions are influenced by other factors, which may be extraneous given the inconsistencies identified in our noise audit. The IRAD's streamlined, empirically informed design and preliminary evidential support may therefore help CBSA better align its decisions with risk
Making Sense of Nonsense in Hong Kong
No full textThis paper identifies some of the challenges facing expatriates using an autoethnographic account of situations experienced by the author during her first year of work at a financial services company in Hong Kong. These experiences reveal an erratic business world of apparent nonsense and uncertainty, incomprehensible to an outsider. The challenges facing expatriates stem from the stress and anxiety affecting their work, family and social interactions within the foreign culture. Success in the new environment is dependent on the expatriate's ability to adjust to the new culture. An overview of the current research on the expatriate experience is provided to help the reader make sense of the autoethnographic situations
On Treaty, Virtue, and Plots that Choose Death: Moses Perley's Sporting Sketches
No full textIt remains somehow contrary to the mythology that Canadian academics have built up around Moses Perley over the course of the past 180 years to say that he believed the elimination of Waponahki people from this land was in his own interest—and yet he clearly did, and not only because this is how settler colonialism works, but because he says as much in his own writings. This article situates Moses Perley’s sporting sketches, first published in the London Sporting Review in the 1830s and 1840s, within the related contexts of self-interest and of what colonial literary historians since Howard Mumford Jones have discussed as “promotion literature.” The author models and advocates for a process of reading the literatures of this land through the Peace and Friendship Treaty relationship—a reading strategy that can draw each of us into the work of restoring our collective treaty order.Il est en quelque sorte contraire à la mythologie que les universitaires canadiens ont construite autour de Moses Perley au cours des 180 dernières années de dire qu'il croyait que l'élimination du peuple Waponahki de cette terre était dans son intérêt personnel – et pourtant c'était clairement le cas, non seulement parce que c'est ainsi que fonctionne le colonialisme de peuplement, mais aussi parce qu’il l’affirme dans ses propres écrits. Cet article situe les esquisses sportives de Moses Perley, publiées pour la première fois dans la London Sporting Review dans les années 1830 et 1840, dans les contextes connexes de l’intérêt personnel et de ce que les historiens de la littérature coloniale, depuis Howard Mumford Jones, ont appelé la « littérature de promotion ». L'auteur modélise et préconise un processus de lecture des littératures de ce pays à travers la relation du traité de paix et d'amitié – une stratégie de lecture qui peut entraîner chacun d’entre nous dans le travail de restauration de l’ordre de notre traité collectif
ALMA and Herschel observations of the prototype dusty and polluted white dwarf G29-38
No full textJF gratefully acknowledges the support of the STFC via an Ernest Rutherford Fellowship. AB acknowledges the support of the ANR-2010 BLAN-0505-01 (EXOZODI). MCW and OP are grateful for the support of the European Union through ERC grant number 279973.ALMA Cycle 0 and Herschel PACS observations are reported for the prototype, nearest, and brightest example of a dusty and polluted white dwarf, G29-38. These long-wavelength programmes attempted to detect an outlying, parent population of bodies at 1–100 au, from which originates the disrupted planetesimal debris that is observed within 0.01 au and which exhibits LIR/L* = 0.039. No associated emission sources were detected in any of the data down to LIR/L* ∼ 10−4, generally ruling out cold dust masses greater than 1024–1025 g for reasonable grain sizes and properties in orbital regions corresponding to evolved versions of both asteroid and Kuiper belt analogues. Overall, these null detections are consistent with models of long-term collisional evolution in planetesimal discs, and the source regions for the disrupted parent bodies at stars like G29-38 may only be salient in exceptional circumstances, such as a recent instability. A larger sample of polluted white dwarfs, targeted with the full ALMA array, has the potential to unambiguously identify the parent source(s) of their planetary debris.Peer reviewe
The long-wavelength view of GG Tau A: rocks in the ring world
No full textWe present the first detection of GG Tau A at centimetre wavelengths, made with the Arcminute Microkelvin Imager Large Array at a frequency of 16 GHz (λ = 1.8 cm). The source is detected at >6 σrms with an integrated flux density of S16GHz = 249 ± 45 µJy. We use these new centimetre-wave data, in conjunction with additional measurements compiled from the literature, to investigate the long-wavelength tail of the dust emission from this unusual protoplanetary system. We use an MCMC-based method to determine maximum likelihood parameters for a simple parametric spectral model and consider the opacity and mass of the dust contributing to the microwave emission. We derive a dust mass of Md ~ 0.1 Msun, constrain the dimensions of the emitting region and find that the opacity index at λ > 7 mm is less than unity, implying a contribution to the dust population from grains exceeding ~4 cm in size. We suggest that this indicates coagulation within the GG Tau A system has proceeded to the point where dust grains have grown to the size of small rocks with dimensions of a few centimetres. Considering the relatively young age of the GG Tau association in combination with the low derived disc mass, we suggest that this system may provide a useful test case for rapid core accretion planet formation models
Spectral ageing in the lobes of FR-II radio galaxies: new methods of analysis for broad-band radio data
No full textThe broad-bandwidth capabilities of next generation telescopes such as the Jansky Very Large Array (JVLA) mean that the spectrum of any given source varies significantly within the bandwidth of any given observation. Detailed spectral analysis taking this variation into account is set to become standard practice when dealing with any new broad-band radio observations; it is therefore vital that methods are developed to handle this new type of data. In this paper, we present the Broadband Radio Astronomy ToolS (brats) software package and, use it to carry out detailed analysis of JVLA observations of three powerful radio galaxies. We compare two of the most widely used models of spectral ageing, the Kardashev–Pacholczyk and Jaffe–Perola models and also results of the more complex, but potentially more realistic, Tribble model. We find that the Tribble model provides both a good fit to observations as well as providing a physically realistic description of the source. We present the first high-resolution spectral maps of our sources and find that the best-fitting injection indices across all models take higher values than have previously been assumed. We present characteristic hotspot advance speeds and make comparison to those derived from dynamical ages, confirming the previously known discrepancy in speed remains present when determined at high spectral resolutions. We show that some previously common assumptions made in determining spectral ages with narrow-band radio telescopes may not always hold and strongly suggest that these are accounted for in future investigations
Fifth annual report: Union County Mosquito Extermination Commission
No full textA yearly series of reports from the Union County Mosquito Extermination Commission. The reports cover finances, inspections, drainage, oiling, and salt marsh, inland, and educational work regarding the extermination and control of mosquitoes in the different towns and districts of Union County, New Jersey
