254 research outputs found

    BootBandit: A macOS bootloader attack

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    Historically, the boot phase on personal computers left systems in a relatively vulnerable state. Because traditional antivirus software runs within the operating system, the boot environment is difficult to protect from malware. Examples of attacks against bootloaders include so‐called “evil maid” attacks, in which an intruder physically obtains a boot disk to install malicious software for obtaining the password used to encrypt a disk. The password then must be stored and retrieved again through physical access. In this paper, we discuss an attack that borrows concepts from the evil maid. We assume exploitation can be used to infect a bootloader on a system running macOS remotely to install code to steal the user\u27s password. We explore the ability to create a communication channel between the bootloader and the operating system to remotely steal the password for a disk protected by FileVault 2. On a macOS system, this attack has additional implications due to “password forwarding” technology, in which a user\u27s account password also serves as the FileVault password, enabling an additional attack surface through privilege escalation

    Contracting Out of the Culture Wars: How the Law Should Enforce and Communities of Faith Should Encourage More Enduring Marital Commitments

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    This article attempts to transcend the “culture wars” as they are played out in the family law arena by drawing on postmodern values, such as individualism and neutrality, to allow individuals who so desire to choose to emphasize more traditional or communitarian values, such as interdependence and attachment. This article argues, then, as others have, that the role of contract in marriage should be extended for those who choose to agree to additional terms. Here, the argument goes a step further, however, by positing an active, positive role for communities of faith to play in a marriage regime of expanded contract. Specifically, this article argues that communities of faith should not only be allowed but, in fact, should be encouraged to define the types of commitments they wish to bless as marriage. This article first lays out some of the background for understanding changes in marriage and divorce in America, including views on what marriage is and should be as well as developments in society’s conceptions of morality and the role of law. It is in this context that this paper presents some of the major legal and non-legal attempts that have been made to strengthen marital commitments. After giving an overview of what others have already written on how expanding the role of contract might be used in this effort, this article builds on successful non-legal approaches used by communities of faith by introducing the idea that such communities also should participate in developing marriage contracts. The rest of this article defends this proposition, both explaining why communities of faith might desire to be involved in such a project as well as attempting to answer critics, especially those concerned about furthering their particular vision for the family in America – whether more progressive or traditional

    Method of Exact Solutions Code Verification of a Superelastic Constitutive Model in a Commercial Finite Element Solver

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    The superelastic constitutive model implemented in the commercial finite element code ABAQUS is verified using the method of exact solutions (MES). An analytical solution for uniaxial strain is first developed under a set of simplifying assumptions including von Mises-like transformation surfaces, symmetric transformation behavior, and monotonic loading. Numerical simulations are then performed, and simulation predictions are compared to the exact analytical solutions. Results reveal the superelasticity model agrees with the analytical solution to within one ten-thousandth of a percent (0.0001%) or less for stress and strain quantities of interest when using displacement-driven boundary conditions. Full derivation of the analytical solution is provided in an Appendix, and simulation input files and post-processing scripts are provided as supplemental material.Comment: 23 pages, 4 figure

    Circadian Activity Rhythms for Mothers with an Infant in ICU

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    Circadian rhythms influence sleep and wakefulness. Circadian activity rhythms (CAR) are altered in individuals with dementia or seasonal affective disorder. To date, studies exploring CAR and sleep in postpartum women are rare. The purpose of this report is to describe relationships between CAR, sleep disturbance, and fatigue among 72 first-time mothers during their second week postpartum while their newborn remain hospitalized in intensive care unit. Seventy-two mothers were included in this secondary data analysis sample from three separate studies. Participants completed the general sleep disturbance scale (GSDS), numerical rating scale for fatigue, and a sleep diary. The objective sleep data included total sleep time (TST), wake after sleep onset (WASO), and CAR determined by the circadian quotient (amplitude/mesor) averaged from at least 48-h of wrist actigraphy monitoring. The TST of mothers who self-reported as poor sleepers was 354 min (SEM = 21.9), with a mean WASO of 19.5% (SEM = 2.8). The overall sleep quality measured by the GSDS was clinically, significantly disrupted (M = 5.5, SD = 1.2). The mean score for morning fatigue was 5.8 (SD = 2.0), indicating moderate fatigue severity. The CAR was 0.62 (SEM = 0.04), indicating poor synchronization. The self-reported good sleepers (GSDS < 3) had better CAR (M = 0.71, SEM = 0.02) than poor sleepers (GSDS > 3) (t[70] = 2.0, p < 0.05). A higher circadian equation was associated with higher TST (r = 0.83, p < 0.001), less WASO (r = −0.50, p < 0.001), lower self-reported sleep disturbance scores (r = −0.35, p = 0.01), and less morning fatigue (r = −0.26). Findings indicate that mothers with a hospitalized infant have both nocturnal sleep problems and disturbed circadian activity rhythms. Factors responsible for these sleep and rhythm disturbances, the adverse effects on mother's physical and mental well-being, and mother–infant relationship require further study

    Imaging thermal conductivity with nanoscale resolution using a scanning spin probe

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    The ability to probe nanoscale heat flow in a material is often limited by lack of spatial resolution. Here, we use a diamond-nanocrystal-hosted nitrogen-vacancy centre attached to the apex of a silicon thermal tip as a local temperature sensor. We apply an electrical current to heat up the tip and rely on the nitrogen vacancy to monitor the thermal changes the tip experiences as it is brought into contact with surfaces of varying thermal conductivity. By combining atomic force and confocal microscopy, we image phantom microstructures with nanoscale resolution, and attain excellent agreement between the thermal conductivity and topographic maps. The small mass and high thermal conductivity of the diamond host make the time response of our technique short, which we demonstrate by monitoring the tip temperature upon application of a heat pulse. Our approach promises multiple applications, from the investigation of phonon dynamics in nanostructures to the characterization of heterogeneous phase transitions and chemical reactions in various solid-state systems

    Imaging thermal conductivity with nanoscale resolution using a scanning spin probe

    Get PDF
    The ability to probe nanoscale heat flow in a material is often limited by lack of spatial resolution. Here, we use a diamond-nanocrystal-hosted nitrogen-vacancy centre attached to the apex of a silicon thermal tip as a local temperature sensor. We apply an electrical current to heat up the tip and rely on the nitrogen vacancy to monitor the thermal changes the tip experiences as it is brought into contact with surfaces of varying thermal conductivity. By combining atomic force and confocal microscopy, we image phantom microstructures with nanoscale resolution, and attain excellent agreement between the thermal conductivity and topographic maps. The small mass and high thermal conductivity of the diamond host make the time response of our technique short, which we demonstrate by monitoring the tip temperature upon application of a heat pulse. Our approach promises multiple applications, from the investigation of phonon dynamics in nanostructures to the characterization of heterogeneous phase transitions and chemical reactions in various solid-state systems

    Managing plagiarism in programming assignments with blended assessment and randomisation.

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    Plagiarism is a common concern for coursework in many situations, particularly where electronic solutions can be provided e.g. computer programs, and leads to unreliability of assessment. Written exams are often used to try to deal with this, and to increase reliability, but at the expense of validity. One solution, outlined in this paper, is to randomise the work that is set for students so that it is very unlikely that any two students will be working on exactly the same problem set. This also helps to address the issue of students trying to outsource their work by paying external people to complete their assignments for them. We examine the effectiveness of this approach and others (including blended assessment) by analysing the spread of similarity scores across four different introductory programming assignments to find the natural similarity i.e. the level of similarity that could reasonably occur without plagiarism. The results of the study indicate that divergent assessment (having more than one possible solution) as opposed to convergent assessment (only one solution) is the dominant factor in natural similarity. A key area for further work is to apply the analysis to a larger sample of programming assignments to better understand the impact of different features of the assignment design on natural similarity and hence the detection of plagiarism
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