Strategies for protecting intellectual property when using CUDA applications on graphics processing units

Recent advances in the massively parallel computational abilities of graphical processing units (GPUs) have increased their use for general purpose computation, as companies look to take advantage of big data processing techniques. This has given rise to the potential for malicious software targeting GPUs, which is of interest to forensic investigators examining the operation of software. The ability to carry out reverse-engineering of software is of great importance within the security and forensics elds, particularly when investigating malicious software or carrying out forensic analysis following a successful security breach. Due to the complexity of the Nvidia CUDA (Compute Uni ed Device Architecture) framework, it is not clear how best to approach the reverse engineering of a piece of CUDA software. We carry out a review of the di erent binary output formats which may be encountered from the CUDA compiler, and their implications on reverse engineering. We then demonstrate the process of carrying out disassembly of an example CUDA application, to establish the various techniques available to forensic investigators carrying out black-box disassembly and reverse engineering of CUDA binaries. We show that the Nvidia compiler, using default settings, leaks useful information. Finally, we demonstrate techniques to better protect intellectual property in CUDA algorithm implementations from reverse engineering

Tests of the Gravitational Inverse-Square Law below the Dark-Energy Length Scale

We conducted three torsion-balance experiments to test the gravitational inverse-square law at separations between 9.53 mm and 55 micrometers, probing distances less than the dark-energy length scale $\lambda_{\rm d}=\sqrt[4]{\hbar c/\rho_{\rm d}}\approx 85 \mu$m. We find with 95% confidence that the inverse-square law holds ($|\alpha| \leq 1$) down to a length scale $\lambda = 56 \mu$m and that an extra dimension must have a size $R \leq 44 \mu$m.Comment: 4 pages, 6 figure

Black hole evolution by spectral methods

Current methods of evolving a spacetime containing one or more black holes are plagued by instabilities that prohibit long-term evolution. Some of these instabilities may be due to the numerical method used, traditionally finite differencing. In this paper, we explore the use of a pseudospectral collocation (PSC) method for the evolution of a spherically symmetric black hole spacetime in one dimension using a hyperbolic formulation of Einstein's equations. We demonstrate that our PSC method is able to evolve a spherically symmetric black hole spacetime forever without enforcing constraints, even if we add dynamics via a Klein-Gordon scalar field. We find that, in contrast to finite-differencing methods, black hole excision is a trivial operation using PSC applied to a hyperbolic formulation of Einstein's equations. We discuss the extension of this method to three spatial dimensions.Comment: 20 pages, 17 figures, submitted to PR

The Thermal Evolution of Ices in the Environments of Newly Formed Stars: The CO_2 Diagnostic

Archival data from the Infrared Spectrometer of the Spitzer Space Telescope are used to study the 15 μm absorption feature of solid CO_2 toward 28 young stellar objects (YSOs) of approximately solar mass. Fits to the absorption profile using laboratory spectra enable categorization according to the degree of thermal processing of the ice matrix that contains the CO_2. The majority of YSOs in our sample (20 out of 28) are found to be consistent with a combination of polar (H_2O-rich) and nonpolar (CO-rich) ices at low temperature; the remainder exhibit profile structure consistent with partial crystallization as the result of significant heating. Ice-phase column densities of CO_2 are determined and compared with those of other species. Lines of sight with crystallization signatures in their spectra are found to be systematically deficient in solid-phase CO, as expected if CO is being sublimated in regions where the ices are heated to crystallization temperatures. Significant variation is found in the CO2 abundance with respect to both H_2O (the dominant ice constituent) and total dust column (quantified by the extinction, AV ). YSOs in our sample display typically higher CO_2 concentrations (independent of evidence for thermal processing) in comparison to quiescent regions of the prototypical cold molecular cloud. This suggests that enhanced CO_2 production is driven by photochemical reactions in proximity to some YSOs, and that photoprocessing and thermal processing may occur independently

Structural and Functional Studies of GDP-6-Deoxy-Talose and GDP-Rhamnose Biosynthetic Enzymes

GDP-6-deoxy-D-talose and its 4-epimer GDP-D-rhamnose are unusual sugars found on the cell surface of certain Gram-negative bacteria. GDP-6-deoxy-talose and GDP-rhamnose are produced by enzymes called GTS and RMD, respectively. These sugars are produced from the same common intermediate and are 4\u27-epimers of each other, which provides an interesting paradigm to study the stereo-selective reduction of unusual sugars. We have determined a novel X-ray crystallographic structure of RMD from Pseudomonas aeruginosa that contains its cosubstrate NADPH within the active site. A superposition of our RMD structure with a previously-determined one gives clear insight into the mechanism of hydride transfer from the cofactor during catalysis. We also report progress toward the structural analysis of GTS and functional analyses of both enzymes. Characterization of GTS and RMD will allow for an understanding of how bacteria utilize these sugars and may give insight into the pathogenicity of certain Gram-negative bacteria. Furthermore, an understanding of the production of unusual sugars can allow for the derivitization of existing antibiotics in an effort to combat bacterial resistance via a process called glycodiversification

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Fusion Research Cente

Estimated National and Regional Impact of COVID-19 on Elective Case Volume in Aesthetic Plastic Surgery.

BACKGROUND:In efforts to help alleviate the strain placed on healthcare during the COVID-19 pandemic, The American Society of Plastic Surgery (ASPS) recommended suspending elective procedures on March 19, 2020. When this suspension was enacted, it was unknown when cases would resume. OBJECTIVES:This analysis aims to estimate the regional economic impact of the pandemic specifically with regards to elective, aesthetic surgical procedures. As knowledge regarding the effects of the pandemic has grown, the authors then evaluated the accuracy of our projected estimates when compared to actual events. METHODS:Using the ASPS 2018 Plastic Surgery Statistics Report, regional case volume and surgeons\u27 fees were obtained for the top five aesthetic procedures. Models developed by the Institute for Health Metrics and Evaluation (IHME) were used to estimate the anticipated duration of suspension by using the date that no ventilators would be required to for COVID-19 patients. This duration was used to calculate the volume of cases that would not occur. RESULTS:These estimates predict up to 1.3 billion fewer dollars will be collected in surgeons\u27 fees, representing a 20% loss compared to 2018. The South Atlantic region is predicted to have the greatest number of OR days lost; However, the Mountain and Pacific regions are estimated to have the greatest loss in case volume and surgeons\u27 fees. CONCLUSIONS:The cumulative impact of the pandemic on life, society, and the economy is tremendous. This analysis may help guide surgeons\u27 responses during and after the crisis

From one solution of a 3-satisfiability formula to a solution cluster: Frozen variables and entropy

A solution to a 3-satisfiability (3-SAT) formula can be expanded into a cluster, all other solutions of which are reachable from this one through a sequence of single-spin flips. Some variables in the solution cluster are frozen to the same spin values by one of two different mechanisms: frozen-core formation and long-range frustrations. While frozen cores are identified by a local whitening algorithm, long-range frustrations are very difficult to trace, and they make an entropic belief-propagation (BP) algorithm fail to converge. For BP to reach a fixed point the spin values of a tiny fraction of variables (chosen according to the whitening algorithm) are externally fixed during the iteration. From the calculated entropy values, we infer that, for a large random 3-SAT formula with constraint density close to the satisfiability threshold, the solutions obtained by the survey-propagation or the walksat algorithm belong neither to the most dominating clusters of the formula nor to the most abundant clusters. This work indicates that a single solution cluster of a random 3-SAT formula may have further community structures.Comment: 13 pages, 6 figures. Final version as published in PR