Software Protection

A computer system's security can be compromised in many ways a denial-of-service attack can make a server inoperable, a worm can destroy a user's private data, or an eavesdrop per can reap financial rewards by inserting himself in the communication link between a customer and her bank through a man-in-the-middle (MITM) attack. What all these scenarios have in common is that the adversary is an untrusted entity that attacks a system from the outside-we assume that the computers under attack are operated by benign and trusted users. But if we remove this assumption, if we allow anyone operating a computer system- from system administrators down to ordinary users-to compromise that system's security, we find ourselves in a scenario that has received comparatively little attention. Methods for protecting against MATE attacks are variously known as anti-tamper techniques, digital asset protection, or, more

Abstract RELATIONSHIPS BETWEEN CUMULATIVE CHILDHOOD ADVERSITY AND SLEEP HEALTH: DOES VIGILANCE FOR THREAT PLAY A ROLE?

Exposure to childhood adversity in the home may be related to poorer sleep, even in samples without sleep disorders or psychiatric illness. Sleep health is a construct that considers dimensions of both nighttime and daytime sleep (i.e., regularity, satisfaction, alertness, timing, efficiency, duration). This study examined the relationship between cumulative childhood adversity (i.e., a sum of different types of adversities) and sleep health, as well as mediators and moderators of this relationship, including vigilance for threat, childhood SES, community adversities, body mass index, and symptoms of depression, anxiety, and PTSD in a sample of 540 healthy undergraduates aged 18-28 years old (50% female; 29% non-white). Online surveys assessed childhood adversity before age 18 and current sleep, mood, vigilance for threat, and health. Survey sleep health was measured using the “RUSATED” scale (Buysse, 2014). A subsample (n=114) completed a laboratory protocol that measured behavioral and physiological vigilance for threat, and a weeklong sleep protocol (actigraphy and daily diaries). Primary analyses examined a second-order latent factor of sleep health that combined survey, actigraphy, and diary measures of the six sleep health dimensions. Supplemental analyses examined the total sleep health score on the RUSATED survey, as well as total scores when RUSATED cut-offs for each sleep dimension were applied to actigraphy and diary data. Structural equation modeling (with bootstrapping for mediation models) and linear regressions were used to examine the relationship between childhood adversity and sleep health. Overall, 52% of the sample reported one or more childhood adversities. Childhood adversity was related to poorer latent sleep health and survey-reported RUSATED sleep health total score after adjustment for sociodemographic, health, and psychosocial covariates. Mediation and moderation hypotheses were largely unsupported, with two exceptions: PTSD partially mediated the relationship between childhood adversity and diary-derived sleep health total score, and low childhood SES moderated the relationship between adversity and survey sleep health total score, but this interaction was not probed as less than 5% of participants reported low SES. The sleep health construct may provide a nuanced way to study sleep patterns and ultimately guide intervention efforts that may mitigate downstream risk of poor health outcomes

Analysis of Ornstein-Uhlenbeck and Laguerre Stochastic Processes

The objective of these lectures is to present Ornstein-Uhlenbeck and related stochastic processes to a wide mathematical audience with a modest preparation in stochastic analysis. The aim of the first part of the lectures (Chapter 1) is to discuss the Ornstein-Uhlenbeck and the Squared Radial Ornstein-Uhlenbeck stochastic diffusion processes, whose infinitesimal generators are, respectively, the Ornstein-Uhlenbeck operator and the Laguerre operator. In the second chapter of these lectures the Ornstein-Uhlenbeck processes governed by -stable rotationally invariant processes are studied. This corresponds to replacing the Laplacian by the fractionnary Laplacian -(-)^/2 in the Ornstein-Uhlenbeck generator L=12-x. More general drift terms b(x) are also considered at the end of Chapter 2.[2mm

Design definition study of a NASA/Navy lift/cruise fan technology V/STOL airplane: Risk assessment addendum to the final report

An assessment of risk, in terms of delivery delays, cost overrun, and performance achievement, associated with the V/STOL technology airplane is presented. The risk is discussed in terms of weight, structure, aerodynamics, propulsion, mechanical drive, and flight controls. The analysis ensures that risks associated with the design and development of the airplane will be eliminated in the course of the program and a useful technology airplane that meets the predicted cost, schedule, and performance can be produced

Upper Bound on the Products of Particle Interactions in Cellular Automata

Particle-like objects are observed to propagate and interact in many spatially extended dynamical systems. For one of the simplest classes of such systems, one-dimensional cellular automata, we establish a rigorous upper bound on the number of distinct products that these interactions can generate. The upper bound is controlled by the structural complexity of the interacting particles---a quantity which is defined here and which measures the amount of spatio-temporal information that a particle stores. Along the way we establish a number of properties of domains and particles that follow from the computational mechanics analysis of cellular automata; thereby elucidating why that approach is of general utility. The upper bound is tested against several relatively complex domain-particle cellular automata and found to be tight.Comment: 17 pages, 12 figures, 3 tables, http://www.santafe.edu/projects/CompMech/papers/ub.html V2: References and accompanying text modified, to comply with legal demands arising from on-going intellectual property litigation among third parties. V3: Accepted for publication in Physica D. References added and other small changes made per referee suggestion

Software protection

A computer system's security can be compromised in many ways—a denial-of-service attack can make a server inoperable, a worm can destroy a user's private data, or an eavesdropper can reap financial rewards by inserting himself in the communication link between a customer and her bank through a man-in-the-middle (MITM) attack. What all these scenarios have in common is that the adversary is an untrusted entity that attacks a system from the outside—we assume that the computers under attack are operated by benign and trusted users. But if we remove this assumption, if we allow anyone operating a computer system—from system administrators down to ordinary users—to compromise that system's security, we find ourselves in a scenario that has received comparatively little attention

Strike point splitting induced by the application of magnetic perturbations on MAST

Divertor strike point splitting induced by resonant magnetic perturbations (RMPs) has been observed on MAST for a variety of RMP configurations in a plasma scenario with Ip=750kA where those configurations all have similar resonant components. Complementary measurements have been obtained with divertor Langmuir probes and an infrared camera. Clear splitting consistently appears in this scenario only in the even configuration of the perturbation coils, similarly to the density pump-out. These results present a challenge for models of plasma response to RMPs.Comment: 9 pages, 4 figures, submitted to the proceedings of the 20th Conference on Plasma Surface Interactions, to be published in the Journal of Nuclear Material