780 research outputs found
ODISEES: Ontology-Driven Interactive Search Environment for Earth Sciences
This paper discusses the Ontology-driven Interactive Search Environment for Earth Sciences (ODISEES) project currently being developed to aid researchers attempting to find usable data among an overabundance of closely related data. ODISEES' ontological structure relies on a modular, adaptable concept modeling approach, which allows the domain to be modeled more or less as it is without worrying about terminology or external requirements. In the model, variables are individually assigned semantic content based on the characteristics of the measurements they represent, allowing intuitive discovery and comparison of data without requiring the user to sift through large numbers of data sets and variables to find the desired information
High-Sensitivity Measurement of 3He-4He Isotopic Ratios for Ultracold Neutron Experiments
Research efforts ranging from studies of solid helium to searches for a
neutron electric dipole moment require isotopically purified helium with a
ratio of 3He to 4He at levels below that which can be measured using
traditional mass spectroscopy techniques. We demonstrate an approach to such a
measurement using accelerator mass spectroscopy, reaching the 10e-14 level of
sensitivity, several orders of magnitude more sensitive than other techniques.
Measurements of 3He/4He in samples relevant to the measurement of the neutron
lifetime indicate the need for substantial corrections. We also argue that
there is a clear path forward to sensitivity increases of at least another
order of magnitude.Comment: 11 pages, 10 figure
V2368 Oph: An eclipsing and double-lined spectroscopic binary used as a photometric comparison star for U Oph
The A-type star HR 6412 = V2368 Oph was used by several investigators as a
photometric comparison star for the known eclipsing binary U Oph but was found
to be variable by three independent groups, including us. By analysing series
of new spectral and photometric observations and a critical compilation of
available radial velocities, we were able to find the correct period of light
and radial-velocity variations and demonstrate that the object is an eclipsing
and double-lined spectroscopic binary moving in a highly eccentric orbit. We
derived a linear ephemeris T min.I = HJD (2454294.67 +/- 0.01) + (38.32712 +/-
0.00004)d x E and estimated preliminary basic physical properties of the
binary. The dereddened UBV magnitudes and effective temperatures of the primary
and secondary, based on our light- and velocity-curve solutions, led to
distance estimates that agree with the Hipparcos distance within the errors. We
find that the mass ratio must be close to one, but the limited number and
wavelength range of our current spectra does not allow a truly precise
determination of the binary masses. Nevertheless, our results show convincingly
that both binary components are evolved away from the main sequence, which
makes this system astrophysically very important. There are only a few
similarly evolved A-type stars among known eclipsing binaries. Future
systematic observations and careful analyses can provide very stringent tests
for the stellar evolutionary theory.Comment: 10 pages, 7 figs, in press 2011 A&
AI ATAC 1: An Evaluation of Prominent Commercial Malware Detectors
This work presents an evaluation of six prominent commercial endpoint malware
detectors, a network malware detector, and a file-conviction algorithm from a
cyber technology vendor. The evaluation was administered as the first of the
Artificial Intelligence Applications to Autonomous Cybersecurity (AI ATAC)
prize challenges, funded by / completed in service of the US Navy. The
experiment employed 100K files (50/50% benign/malicious) with a stratified
distribution of file types, including ~1K zero-day program executables
(increasing experiment size two orders of magnitude over previous work). We
present an evaluation process of delivering a file to a fresh virtual machine
donning the detection technology, waiting 90s to allow static detection, then
executing the file and waiting another period for dynamic detection; this
allows greater fidelity in the observational data than previous experiments, in
particular, resource and time-to-detection statistics. To execute all 800K
trials (100K files 8 tools), a software framework is designed to
choreographed the experiment into a completely automated, time-synced, and
reproducible workflow with substantial parallelization. A cost-benefit model
was configured to integrate the tools' recall, precision, time to detection,
and resource requirements into a single comparable quantity by simulating costs
of use. This provides a ranking methodology for cyber competitions and a lens
through which to reason about the varied statistical viewpoints of the results.
These statistical and cost-model results provide insights on state of
commercial malware detection
Beyond the Hype: A Real-World Evaluation of the Impact and Cost of Machine Learning-Based Malware Detection
There is a lack of scientific testing of commercially available malware
detectors, especially those that boast accurate classification of
never-before-seen (i.e., zero-day) files using machine learning (ML). The
result is that the efficacy and gaps among the available approaches are opaque,
inhibiting end users from making informed network security decisions and
researchers from targeting gaps in current detectors. In this paper, we present
a scientific evaluation of four market-leading malware detection tools to
assist an organization with two primary questions: (Q1) To what extent do
ML-based tools accurately classify never-before-seen files without sacrificing
detection ability on known files? (Q2) Is it worth purchasing a network-level
malware detector to complement host-based detection? We tested each tool
against 3,536 total files (2,554 or 72% malicious, 982 or 28% benign) including
over 400 zero-day malware, and tested with a variety of file types and
protocols for delivery. We present statistical results on detection time and
accuracy, consider complementary analysis (using multiple tools together), and
provide two novel applications of a recent cost-benefit evaluation procedure by
Iannaconne & Bridges that incorporates all the above metrics into a single
quantifiable cost. While the ML-based tools are more effective at detecting
zero-day files and executables, the signature-based tool may still be an
overall better option. Both network-based tools provide substantial (simulated)
savings when paired with either host tool, yet both show poor detection rates
on protocols other than HTTP or SMTP. Our results show that all four tools have
near-perfect precision but alarmingly low recall, especially on file types
other than executables and office files -- 37% of malware tested, including all
polyglot files, were undetected.Comment: Includes Actionable Takeaways for SOC
High-sensitivity measurement of ^3He−^4He isotopic ratios for ultracold neutron experiments
Research efforts ranging from studies of solid helium to searches for a neutron electric dipole moment require isotopically purified helium with a ratio of ^3He to ^4He at levels below that which can be measured using traditional mass spectroscopy techniques. We demonstrate an approach to such a measurement using accelerator mass spectroscopy, reaching the 10^(−14) level of sensitivity, several orders of magnitude more sensitive than other techniques. Measurements of ^3He/^4He in samples relevant to the measurement of the neutron lifetime indicate the need for substantial corrections. We also argue that there is a clear path forward to sensitivity increases of at least another order of magnitude
Supernova / Acceleration Probe: A Satellite Experiment to Study the Nature of the Dark Energy
The Supernova / Acceleration Probe (SNAP) is a proposed space-based
experiment designed to study the dark energy and alternative explanations of
the acceleration of the Universe's expansion by performing a series of
complementary systematics-controlled measurements. We describe a
self-consistent reference mission design for building a Type Ia supernova
Hubble diagram and for performing a wide-area weak gravitational lensing study.
A 2-m wide-field telescope feeds a focal plane consisting of a 0.7
square-degree imager tiled with equal areas of optical CCDs and near infrared
sensors, and a high-efficiency low-resolution integral field spectrograph. The
SNAP mission will obtain high-signal-to-noise calibrated light-curves and
spectra for several thousand supernovae at redshifts between z=0.1 and 1.7. A
wide-field survey covering one thousand square degrees resolves ~100 galaxies
per square arcminute. If we assume we live in a cosmological-constant-dominated
Universe, the matter density, dark energy density, and flatness of space can
all be measured with SNAP supernova and weak-lensing measurements to a
systematics-limited accuracy of 1%. For a flat universe, the
density-to-pressure ratio of dark energy can be similarly measured to 5% for
the present value w0 and ~0.1 for the time variation w'. The large survey area,
depth, spatial resolution, time-sampling, and nine-band optical to NIR
photometry will support additional independent and/or complementary dark-energy
measurement approaches as well as a broad range of auxiliary science programs.
(Abridged)Comment: 40 pages, 18 figures, submitted to PASP, http://snap.lbl.go
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