8,095 research outputs found
Arguing Machines: Human Supervision of Black Box AI Systems That Make Life-Critical Decisions
We consider the paradigm of a black box AI system that makes life-critical
decisions. We propose an "arguing machines" framework that pairs the primary AI
system with a secondary one that is independently trained to perform the same
task. We show that disagreement between the two systems, without any knowledge
of underlying system design or operation, is sufficient to arbitrarily improve
the accuracy of the overall decision pipeline given human supervision over
disagreements. We demonstrate this system in two applications: (1) an
illustrative example of image classification and (2) on large-scale real-world
semi-autonomous driving data. For the first application, we apply this
framework to image classification achieving a reduction from 8.0% to 2.8% top-5
error on ImageNet. For the second application, we apply this framework to Tesla
Autopilot and demonstrate the ability to predict 90.4% of system disengagements
that were labeled by human annotators as challenging and needing human
supervision
The Impact of Type Ia Supernovae in Quiescent Galaxies: I. Formation of the Multiphase Interstellar medium
A cool phase of the interstellar medium has been observed in many giant
elliptical galaxies, but its origin remains unclear. We propose that uneven
heating from Type Ia supernovae (SNe Ia), together with radiative cooling, can
lead to the formation of the cool phase. The basic idea is that since SNe Ia
explode randomly, gas parcels which are not directly heated by SN shocks will
cool, forming multiphase gas. We run a series of idealized high-resolution
numerical simulations, and find that cool gas develops even when the overall
SNe heating rate exceeds the cooling rate by a factor as large as 1.4.
We also find that the time for multiphase gas development depends on the gas
temperature. When the medium has a temperature K, the cool
phase forms within one cooling time \tc; however, the cool phase formation is
delayed to a few times \tc\ for higher temperatures. The main reason for the
delay is turbulent mixing. Cool gas formed this way would naturally have a
metallicity lower than that of the hot medium. For constant , there is
more turbulent mixing for higher temperature gas. We note that this mechanism
of producing cool gas cannot be captured in cosmological simulations, which
usually fail to resolve individual SN remnants.Comment: 16 pages, 11 figures, published by ApJ. This work is part of the
SMAUG project, see more information at
https://www.simonsfoundation.org/flatiron/center-for-computational-astrophysics/galaxy-formation/smaug/papersplash
The Quantum McKay Correspondence for polyhedral singularities
Let G be a polyhedral group, namely a finite subgroup of SO(3). Nakamura's
G-Hilbert scheme provides a preferred Calabi-Yau resolution Y of the polyhedral
singularity C^3/G. The classical McKay correspondence describes the classical
geometry of Y in terms of the representation theory of G. In this paper we
describe the quantum geometry of Y in terms of R, an ADE root system associated
to G. Namely, we give an explicit formula for the Gromov-Witten partition
function of Y as a product over the positive roots of R. In terms of counts of
BPS states (Gopakumar-Vafa invariants), our result can be stated as a
correspondence: each positive root of R corresponds to one half of a genus zero
BPS state. As an application, we use the crepant resolution conjecture to
provide a full prediction for the orbifold Gromov-Witten invariants of [C^3/G].Comment: Introduction rewritten. Issue regarding non-uniqueness of conifold
resolution clarified. Version to appear in Inventione
Supernova Feedback and the Hot Gas Filling Fraction of the Interstellar Medium
Supernovae (SN), the most energetic stellar feedback mechanism, are crucial
for regulating the interstellar medium (ISM) and launching galactic winds. We
explore how supernova remnants (SNRs) create a multiphase medium by performing
3D hydrodynamical simulations at various SN rates, , and ISM average
densities, . The evolution of a SNR in a self-consistently generated
three-phase ISM is qualitatively different from that in a uniform or a
two-phase warm/cold medium. By travelling faster and further in the low-density
hot phase, the domain of a SNR increases by . Varying and
, we find that a steady state can only be achieved when the hot gas volume
fraction . Above that level, overlapping
SNRs render connecting topology of the hot gas, and the ISM is subjected to
thermal runaway. Photoelectric heating (PEH) has a surprisingly strong impact
on . For \bar{n}\gtrsim 3 \cm-3 , a reasonable PEH rate is
able to suppress the thermal runaway. Overall, we determine the critical SN
rate for the onset of thermal runaway to be S_{\rm{crit}} = 200
(\bar{n}/1\cm-3)^k (E_{\rm{SN}}/10^{51}\erg)^{-1} \kpc^{-3} \myr-1, where for and > 1\cm-3 , respectively. We present a
fitting formula of the ISM pressure , ), which can be used as an
effective equation of state in cosmological simulations. Despite the 5 orders
of magnitude span of , the average Mach number varies little:
for the hot, warm
and cold phases, respectively.Comment: 57 pages, 16 figures, 3 tables. ApJ accepte
Gromov-Witten invariants of blow-ups along submanifolds with convex normal bundles
Given a submanifold Z inside X, let Y be the blow-up of X along Z. When the
normal bundle of Z in X is convex with a minor assumption, we prove that
genus-zero GW-invariants of Y with cohomology insertions from X, are identical
to GW-invariants of X. Under the same hypothesis, a vanishing theorem is also
proved. An example to which these two theorems apply is when the normal bundle
is generated by global sections. These two main theorems do not hold for
arbitrary blow-ups, and counter-examples are included.Comment: 34 page
VISUAL GROUP IN ONLINE COMMUNICATION AND COLLABORATION FACILITY MEETING OR WEBINAR
In a normal work mode, most of a company’s employees will be in an office. If those individuals would like to join a big event (such as an all-hands meeting) as a team or as a group, they are able to gather together in a telepresence (TP) room. Today, as a result of the coronavirus disease 2019 (COVID-19), many people have chosen a hybrid work mode. Under such a mode, it is not easy for all of a team’s members to gather together in the same TP room since, for example, some of the team members may work from home and other of the team members may work in an office. To address the challenge that was described above, techniques are presented herein that provide a means under which people may join a meeting or a webinar, as a visual group, from different locations in a hybrid work mode. Aspects of the presented techniques eliminate dependence on any devices
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