9,863 research outputs found
On the standard errors of Oaxaca-type decompositions for inter-industry gender wage differentials
Horrace and Oaxaca (2001) treat the regressors in gender wage gap by industry measures as non-stochastic when computing the corresponding standard errors. However, the non-stochastic regressors assumption is thought to be inappropriate in modern econometrics. In this paper, we derive the correct standard errors for the measures proposed by Horrace and Oaxaca (2001). We then empirically apply the derived correct standard errors in regard to the March 1998 Current Population Survey data adopted in Horrace and Oaxaca (2001), as well as the Manpower Utilization Survey in the Taiwan area conducted by the Census Bureau over the years from 1978 to 2003. The empirical results suggest that the researchers would be better to use the correct standard errors derived in this paper, accompanied by the White correction, to arrive at a more accurate statistical inference.Gender wage gap
Detecting Multipartite Classical States and their Resemblances
We study various types of multipartite states lying near the
quantum-classical boundary. The class of so-called classical states are
precisely those in which each party can perform a projective measurement to
identify a locally held state without disturbing the global state, a task known
as non-disruptive local state identification (NDLID). We introduce a new class
of states called generalized-classical states which allow for NDLID when the
most general quantum measurements are permitted. A simple analytic method as
well as a physical criterion are presented for detecting whether a multipartite
state is classical. To decide whether a state is generalized-classical, we
provide a semi-definite programming algorithm which can be adapted for use in
other unrelated contexts such as signal processing
Cool Core Bias in Sunyaev-Zel'dovich Galaxy Cluster Surveys
Sunyaev-Zeldovich (SZ) surveys find massive clusters of galaxies by measuring
the inverse Compton scattering of cosmic microwave background off of
intra-cluster gas. The cluster selection function from such surveys is expected
to be nearly independent of redshift and cluster astrophysics. In this work, we
estimate the effect on the observed SZ signal of centrally-peaked gas density
profiles (cool cores) and radio emission from the brightest cluster galaxy
(BCG) by creating mock observations of a sample of clusters that span the
observed range of classical cooling rates and radio luminosities. For each
cluster, we make simulated SZ observations by the South Pole Telescope and
characterize the cluster selection function, but note that our results are
broadly applicable to other SZ surveys. We find that the inclusion of a cool
core can cause a change in the measured SPT significance of a cluster between
0.01% - 10% at z > 0.3, increasing with cuspiness of the cool core and angular
size on the sky of the cluster (i.e., decreasing redshift, increasing mass). We
provide quantitative estimates of the bias in the SZ signal as a function of a
gas density cuspiness parameter, redshift, mass, and the 1.4 GHz radio
luminosity of the central AGN. Based on this work, we estimate that, for the
Phoenix cluster (one of the strongest cool cores known), the presence of a cool
core is biasing the SZ significance high by ~ 6%. The ubiquity of radio
galaxies at the centers of cool core clusters will offset the cool core bias to
varying degrees.Comment: 8 pages, 4 figures, accepted to Ap
Completing incomplete cohort fertility schedules
This paper develops a simple age-period-cohort framework in completing incomplete cohort fertility schedules, and makes full use of 1917--2005 U.S. data to obtain robust outcomes. Empirically, we indicate that the period effect is the key to transforming a fertility level into a fertility schedule. Accompanied by the smoothed version of tempo-variance-adjusted total fertility rates proposed in Kohler and Philipov (2001), we approximate the cohort fertility schedules fairly well and the estimates of all distributional parameters can be thereby obtained. Our approach is easy to implement and the data requirement is relatively light, indicating that the proposed method is readily applicable to countries whose data lengths are insufficiently long, and would be helpful for further empirical investigation of the relationship between cohort fertility behavior and other cohort-specific socioeconomic factors.APC model, cohort fertility schedule, fertility forecast
Electrical power dissipation in carbon nanotubes on single crystal quartz and amorphous SiO2
Heat dissipation in electrically biased semiconducting carbon nanotubes
(CNTs) on single crystal quartz and amorphous SiO2 is examined with temperature
profiles obtained by spatially resolved Raman spectroscopy. Despite the
differences in phonon velocities, thermal conductivity and van der Waals
interactions with CNTs, on average, heat dissipation into single crystal quartz
and amorphous SiO2 is found to be similar. Large temperature gradients and
local hot spots often observed underscore the complexity of CNT temperature
profiles and may be accountable for the similarities observed
Metareasoning for Planning Under Uncertainty
The conventional model for online planning under uncertainty assumes that an
agent can stop and plan without incurring costs for the time spent planning.
However, planning time is not free in most real-world settings. For example, an
autonomous drone is subject to nature's forces, like gravity, even while it
thinks, and must either pay a price for counteracting these forces to stay in
place, or grapple with the state change caused by acquiescing to them. Policy
optimization in these settings requires metareasoning---a process that trades
off the cost of planning and the potential policy improvement that can be
achieved. We formalize and analyze the metareasoning problem for Markov
Decision Processes (MDPs). Our work subsumes previously studied special cases
of metareasoning and shows that in the general case, metareasoning is at most
polynomially harder than solving MDPs with any given algorithm that disregards
the cost of thinking. For reasons we discuss, optimal general metareasoning
turns out to be impractical, motivating approximations. We present approximate
metareasoning procedures which rely on special properties of the BRTDP planning
algorithm and explore the effectiveness of our methods on a variety of
problems.Comment: Extended version of IJCAI 2015 pape
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