3,602 research outputs found
CVA and FVA to Derivatives Trades Collateralized by Cash
In this article, we combine replication pricing with expectation pricing for
derivative trades that are partially collateralized by cash. The derivatives
are replicated by underlying assets and cash, using repurchasing agreement
(repo) and margining, which incur funding costs. We derive a partial
differential equation (PDE) for the derivatives price, obtain and decompose its
solution into the risk-free value of the derivative plus credit valuation
adjustment (CVA) and funding valuation adjustment (FVA). For most derivatives,
as we shall show, CVAs can be evaluated analytically or semi-analytically,
while FVAs, as well as the derivatives values, will have to be solved
recursively through numerical procedures due to their interdependence. In
numerical demonstrations, continuous and discrete margin revisions are
considered, respectively, for an equity call option and a vanilla interest-rate
swaps.Comment: 29 pages, 4 figure
MiniMax Entropy Network: Learning Category-Invariant Features for Domain Adaptation
How to effectively learn from unlabeled data from the target domain is
crucial for domain adaptation, as it helps reduce the large performance gap due
to domain shift or distribution change. In this paper, we propose an
easy-to-implement method dubbed MiniMax Entropy Networks (MMEN) based on
adversarial learning. Unlike most existing approaches which employ a generator
to deal with domain difference, MMEN focuses on learning the categorical
information from unlabeled target samples with the help of labeled source
samples. Specifically, we set an unfair multi-class classifier named
categorical discriminator, which classifies source samples accurately but be
confused about the categories of target samples. The generator learns a common
subspace that aligns the unlabeled samples based on the target pseudo-labels.
For MMEN, we also provide theoretical explanations to show that the learning of
feature alignment reduces domain mismatch at the category level. Experimental
results on various benchmark datasets demonstrate the effectiveness of our
method over existing state-of-the-art baselines.Comment: 8 pages, 6 figure
Constraints on a decomposed dark fluid with constant adiabatic sound speed by jointing the geometry test and growth rate after Planck data
In this paper, a unified dark fluid with constant adiabatic sound speed is
decomposed into cold dark matter interacting with vacuum energy. Based on
Markov chain Monte Carlo method, we constrain this model by jointing the
geometry and dynamical measurement. The geometry test includes cosmic microwave
background radiation from \textit{Planck}, baryon acoustic oscillation, and
type Ia supernovae; the dynamic measurement is data points which
is obtained from the growth rate via redshift-space distortion, and
is the root-mean-square amplitude of the density contrast
at the comoving Mpc scale. The jointed constraint shows that
= and = . The CMB and matter power spectra are both similar for the
case of mean value and that of . However, the evolutionary
curves of are different. This means that, to some extent, the
data points of the growth rate could break the degeneracy of the dark energy
models.Comment: 11 pages, 5 figures. arXiv admin note: text overlap with
arXiv:1311.341
A CO observation of the galactic methanol masers
Context: We investigated the molecular gas associated with 6.7 GHz methanol
masers throughout the Galaxy using a J=1-0 transition of the CO isotopologues.
Methods:Using the 13.7-meter telescope at the Purple Mountain Observatory
(PMO), we have obtained ^{12}CO and ^{13}CO (1-0) lines for 160 methanol masers
sources from the first to the third Galactic quadrants. We made efforts to
resolve the distance ambiguity by careful comparison with the radio continuum
and HI 21 cm observations.
Results: First, the maser sources show increased ^{13}CO line widths toward
the Galactic center, suggesting that the molecular gas are more turbulent
toward the Galactic center. This trend can be noticeably traced by the ^{13}CO
line width. Second, the ^{12}CO excitation temperature shows a noticeable
correlation with the H_2 column density. A possible explanation consistent with
the collapse model is that the higher surface-density gas is more efficient to
the stellar heating and/or has a higher formation rate of high-mass stars.
Third, comparing the IRDCs, the maser sources on average have significantly
lower H_2 column densities, moderately higher temperatures, and similar line
widths. Fourth, in the mapped regions, 51 ^{13}CO cores have been revealed.
Only 17 coincide with the radio continuum emission (F_{cm}>6 mJy), while a
larger fraction (30 cores) coincide with the infrared emissions. The IR-bright
and radio-bright sources exhibit significantly higher CO excitation
temperatures than the IR-faint and radio-faint sources, respectively.
Conclusions: The 6.7 GHz masers show a moderately low ionization rate but
have a common-existing stellar heating that generates the IR emissions. The
relevant properties can be characterized by the ^{12}CO and ^{13}CO (1-0)
emissions in several aspects as described above.Comment: 38 pages, 13 figures, 4 tables, accepted to Astronomy and
Astrophysic
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