372,982 research outputs found
The Cure: Making a game of gene selection for breast cancer survival prediction
Motivation: Molecular signatures for predicting breast cancer prognosis could
greatly improve care through personalization of treatment. Computational
analyses of genome-wide expression datasets have identified such signatures,
but these signatures leave much to be desired in terms of accuracy,
reproducibility and biological interpretability. Methods that take advantage of
structured prior knowledge (e.g. protein interaction networks) show promise in
helping to define better signatures but most knowledge remains unstructured.
Crowdsourcing via scientific discovery games is an emerging methodology that
has the potential to tap into human intelligence at scales and in modes
previously unheard of. Here, we developed and evaluated a game called The Cure
on the task of gene selection for breast cancer survival prediction. Our
central hypothesis was that knowledge linking expression patterns of specific
genes to breast cancer outcomes could be captured from game players. We
envisioned capturing knowledge both from the players prior experience and from
their ability to interpret text related to candidate genes presented to them in
the context of the game.
Results: Between its launch in Sept. 2012 and Sept. 2013, The Cure attracted
more than 1,000 registered players who collectively played nearly 10,000 games.
Gene sets assembled through aggregation of the collected data clearly
demonstrated the accumulation of relevant expert knowledge. In terms of
predictive accuracy, these gene sets provided comparable performance to gene
sets generated using other methods including those used in commercial tests.
The Cure is available at http://genegames.org/cure
Photometric Redshifts of Quasars
We demonstrate that the design of the Sloan Digital Sky Survey (SDSS) filter
system and the quality of the SDSS imaging data are sufficient for determining
accurate and precise photometric redshifts (``photo-z''s) of quasars. Using a
sample of 2625 quasars, we show that photo-z determination is even possible for
z<=2.2 despite the lack of a strong continuum break that robust photo-z
techniques normally require. We find that, using our empirical method on our
sample of objects known to be quasars, approximately 70% of the photometric
redshifts are correct to within delta z = 0.2; the fraction of correct
photometric redshifts is even better for z>3. The accuracy of quasar
photometric redshifts does not appear to be dependent upon magnitude to nearly
21st magnitude in i'. Careful calibration of the color-redshift relation to
21st magnitude may allow for the discovery of on the order of 10^6 quasars
candidates in addition to the 10^5 quasars that the SDSS will confirm
spectroscopically. We discuss the efficient selection of quasar candidates from
imaging data for use with the photometric redshift technique and the potential
scientific uses of a large sample of quasar candidates with photometric
redshifts.Comment: 29 pages, 8 figures, submitted to A
Autonomous System-Level Fault Diagnosis in Satellites Using Housekeeping Telemetry
To continue the growing success of scientific discovery through deep space exploration, missions need to be able to be able to travel further and operate more efficiently than ever before. To ensure resilience in this capability, on-board autonomous fault mitigation methods must be developed and matured. To this end, we present a system for cross-subsystem fault diagnosis of satellites using spacecraft telemetry. Our system leverages a combination of Kalman Filters, Autoencoders, and Causality algorithms. We test our system for accuracy against three data sets of varying complexity levels, along with baseline testing. Additionally, we perform an ablation study to evaluate on-board tractability
Using Artificial Intelligence to aid Scientific Discovery of Climate Tipping Points
We propose a hybrid Artificial Intelligence (AI) climate modeling approach
that enables climate modelers in scientific discovery using a climate-targeted
simulation methodology based on a novel combination of deep neural networks and
mathematical methods for modeling dynamical systems. The simulations are
grounded by a neuro-symbolic language that both enables question answering of
what is learned by the AI methods and provides a means of explainability. We
describe how this methodology can be applied to the discovery of climate
tipping points and, in particular, the collapse of the Atlantic Meridional
Overturning Circulation (AMOC). We show how this methodology is able to predict
AMOC collapse with a high degree of accuracy using a surrogate climate model
for ocean interaction. We also show preliminary results of neuro-symbolic
method performance when translating between natural language questions and
symbolically learned representations. Our AI methodology shows promising early
results, potentially enabling faster climate tipping point related research
that would otherwise be computationally infeasible.Comment: This is the preprint of work presented at the 2022 AAAI Fall
Symposium Series, Third Symposium on Knowledge-Guided ML, November 202
On the Completeness of Reflex Astrometry on Extrasolar Planets near the Sensitivity Limit
We provide a preliminary estimate of the performance of reflex astrometry on
Earth-like planets in the habitable zones of nearby stars. In Monte Carlo
experiments, we analyze large samples of astrometric data sets with low to
moderate signal-to-noise ratios. We treat the idealized case of a single planet
orbiting a single star, and assume there are no non-Keplerian complications or
uncertainties. The real case can only be more difficult. We use periodograms
for discovery and least-squares fits for estimating the Keplerian parameters.
We find a completeness for detection compatible with estimates in the
literature. We find mass estimation by least squares to be biased, as has been
found for noisy radial-velocity data sets; this bias degrades the completeness
of accurate mass estimation. When we compare the true planetary position with
the position predicted from the fitted orbital parameters, at future times, we
find low completeness for an accuracy goal of 0.3 times the semimajor axis of
the planet, even with no delay following the end of astrometric observations.
Our findings suggest that the recommendation of the ExoPlanet Task Force
(Lunine et al. 2008) for "the capability to measure convincingly wobble
semi-amplitudes down to 0.2 as integrated over the mission lifetime," may
not be satisfied by an instrument characterized by the noise floor of the Space
Interferometry Mission, as. An important,
unsolved, strategic challenge for the exoplanetary science program is figuring
out how to predict the future position of an Earth-like planet with accuracy
sufficient to ensure the efficiency and success of the science operations for
follow-on spectroscopy, which would search for biologically significant
molecules in the atmosphere.Comment: v2: 16 pages, 4 figures; ApJ accepte
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