6,949 research outputs found
Enabling electronic prognostics using thermal data
Prognostics is a process of assessing the extent of deviation or degradation
of a product from its expected normal operating condition, and then, based on
continuous monitoring, predicting the future reliability of the product. By
being able to determine when a product will fail, procedures can be developed
to provide advanced warning of failures, optimize maintenance, reduce life
cycle costs, and improve the design, qualification and logistical support of
fielded and future systems. In the case of electronics, the reliability is
often influenced by thermal loads, in the form of steady-state temperatures,
power cycles, temperature gradients, ramp rates, and dwell times. If one can
continuously monitor the thermal loads, in-situ, this data can be used in
conjunction with precursor reasoning algorithms and stress-and-damage models to
enable prognostics. This paper discusses approaches to enable electronic
prognostics and provides a case study of prognostics using thermal data.Comment: Submitted on behalf of TIMA Editions
(http://irevues.inist.fr/tima-editions
Food Insecurity Rates Rise Steeply with Recession
Children's HealthWatch finds that the prevalence of food insecurity in a five-city sample of low-income families with young children increased from 18.5 percent to 22.6 percent between 2007 and 2008. This is the largest year-to-year change seen in the dataset since 2001. The increase is an indication of the economic hardships facing low-income families with young children. This data suggests that we are likely to see significant increases in food insecurity when the U.S. Department of Agriculture issues its own statistics for 2008 in late fall
A circular model for song motor control in Serinus canaria
Song production in songbirds is controlled by a network of nuclei distributed across several brain regions, which drives respiratory and vocal motor systems to generate sound. We built a model for birdsong production, whose variables are the average activities of different neural populations within these nuclei of the song system. We focus on the predictions of respiratory patterns of song, because these can be easily measured and therefore provide a validation for the model. We test the hypothesis that it is possible to construct a model in which (1) the activity of an expiratory related (ER) neural population fits the observed pressure patterns used by canaries during singing, and (2) a higher forebrain neural population, HVC, is sparsely active, simultaneously with significant motor instances of the pressure patterns. We show that in order to achieve these two requirements, the ER neural population needs to receive two inputs: a direct one, and its copy after being processed by other areas of the song system. The model is capable of reproducing the measured respiratory patterns and makes specific predictions on the timing of HVC activity during their production. These results suggest that vocal production is controlled by a circular network rather than by a simple top-down architecture.Fil: Alonso, Rodrigo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física. Laboratorio de Sistemas Dinámicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Trevisan, Marcos Alberto. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física. Laboratorio de Sistemas Dinámicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Amador, Ana. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física. Laboratorio de Sistemas Dinámicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Goller, Franz. University Of Utah. Department Of Biology; Estados UnidosFil: Mindlin, Bernardo Gabriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física. Laboratorio de Sistemas Dinámicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Wage Earners’ Priority in Bankruptcy: Application to Welfare Fund Payments
This paper describes a study on how cyber security experts assess the importance of three variables related to the probability of successful remote code execution attacks – presence of: (i) non-executable memory, (ii) access and (iii) exploits for High or Medium vulnerabilities as defined by the Common Vulnerability Scoring System. The rest of the relevant variables were fixed by the environment of a cyber defense exercise where the respondents participated. The questionnaire was fully completed by fifteen experts. These experts perceived access as the most important variable and availability of exploits for High vulnerabilities as more important than Medium vulnerabilities. Non-executable memory was not seen as significant, however, presumably due to lack of address space layout randomization and canaries in the network architecture of the cyber defense exercise scenario.QC 20140908</p
The Extreme Microlensing Event OGLE-2007-BLG-224: Terrestrial Parallax Observation of a Thick-Disk Brown Dwarf
Parallax is the most fundamental technique to measure distances to
astronomical objects. Although terrestrial parallax was pioneered over 2000
years ago by Hipparchus (ca. 140 BCE) to measure the distance to the Moon, the
baseline of the Earth is so small that terrestrial parallax can generally only
be applied to objects in the Solar System. However, there exists a class of
extreme gravitational microlensing events in which the effects of terrestrial
parallax can be readily detected and so permit the measurement of the distance,
mass, and transverse velocity of the lens. Here we report observations of the
first such extreme microlensing event OGLE-2007-BLG-224, from which we infer
that the lens is a brown dwarf of mass M=0.056 +- 0.004 Msun, with a distance
of 525 +- 40 pc and a transverse velocity of 113 +- 21 km/s. The velocity
places the lens in the thick disk, making this the lowest-mass thick-disk brown
dwarf detected so far. Follow-up observations may allow one to observe the
light from the brown dwarf itself, thus serving as an important constraint for
evolutionary models of these objects and potentially opening a new window on
sub-stellar objects. The low a priori probability of detecting a thick-disk
brown dwarf in this event, when combined with additional evidence from other
observations, suggests that old substellar objects may be more common than
previously assumed.Comment: ApJ Letters, in press, 15 pages including 2 figure
Shining Light On Shadow Stacks
Control-Flow Hijacking attacks are the dominant attack vector against C/C++
programs. Control-Flow Integrity (CFI) solutions mitigate these attacks on the
forward edge,i.e., indirect calls through function pointers and virtual calls.
Protecting the backward edge is left to stack canaries, which are easily
bypassed through information leaks. Shadow Stacks are a fully precise mechanism
for protecting backwards edges, and should be deployed with CFI mitigations. We
present a comprehensive analysis of all possible shadow stack mechanisms along
three axes: performance, compatibility, and security. For performance
comparisons we use SPEC CPU2006, while security and compatibility are
qualitatively analyzed. Based on our study, we renew calls for a shadow stack
design that leverages a dedicated register, resulting in low performance
overhead, and minimal memory overhead, but sacrifices compatibility. We present
case studies of our implementation of such a design, Shadesmar, on Phoronix and
Apache to demonstrate the feasibility of dedicating a general purpose register
to a security monitor on modern architectures, and the deployability of
Shadesmar. Our comprehensive analysis, including detailed case studies for our
novel design, allows compiler designers and practitioners to select the correct
shadow stack design for different usage scenarios.Comment: To Appear in IEEE Security and Privacy 201
Patterns of genetic diversity in three plant lineages endemic to the Cape Verde Islands
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. The file attached is the published version of the article
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