3,812 research outputs found
Totally Corrective Multiclass Boosting with Binary Weak Learners
In this work, we propose a new optimization framework for multiclass boosting
learning. In the literature, AdaBoost.MO and AdaBoost.ECC are the two
successful multiclass boosting algorithms, which can use binary weak learners.
We explicitly derive these two algorithms' Lagrange dual problems based on
their regularized loss functions. We show that the Lagrange dual formulations
enable us to design totally-corrective multiclass algorithms by using the
primal-dual optimization technique. Experiments on benchmark data sets suggest
that our multiclass boosting can achieve a comparable generalization capability
with state-of-the-art, but the convergence speed is much faster than stage-wise
gradient descent boosting. In other words, the new totally corrective
algorithms can maximize the margin more aggressively.Comment: 11 page
Note on Soft Graviton theorem by KLT Relation
Recently, new soft graviton theorem proposed by Cachazo and Strominger has
inspired a lot of works. In this note, we use the KLT-formula to investigate
the theorem. We have shown how the soft behavior of color ordered Yang-Mills
amplitudes can be combined with KLT relation to give the soft behavior of
gravity amplitudes. As a byproduct, we find two nontrivial identities of the
KLT momentum kernel must hold.Comment: 25 page
Faster Mutation Analysis via Equivalence Modulo States
Mutation analysis has many applications, such as asserting the quality of
test suites and localizing faults. One important bottleneck of mutation
analysis is scalability. The latest work explores the possibility of reducing
the redundant execution via split-stream execution. However, split-stream
execution is only able to remove redundant execution before the first mutated
statement.
In this paper we try to also reduce some of the redundant execution after the
execution of the first mutated statement. We observe that, although many
mutated statements are not equivalent, the execution result of those mutated
statements may still be equivalent to the result of the original statement. In
other words, the statements are equivalent modulo the current state.
In this paper we propose a fast mutation analysis approach, AccMut. AccMut
automatically detects the equivalence modulo states among a statement and its
mutations, then groups the statements into equivalence classes modulo states,
and uses only one process to represent each class. In this way, we can
significantly reduce the number of split processes. Our experiments show that
our approach can further accelerate mutation analysis on top of split-stream
execution with a speedup of 2.56x on average.Comment: Submitted to conferenc
Strong Optical and UV Intermediate-Width Emission Lines in the Quasar SDSS J232444.80-094600.3: Dust-Free and Intermediate-Density Gas at the Skin of Dusty Torus ?
Emission lines from the broad emission line region (BELR) and the narrow
emission line region (NELR) of active galactic nuclei (AGNs) are extensively
studied. However, between these two regions emission lines are rarely detected.
We present a detailed analysis of a quasar SDSS J232444.80-094600.3 (SDSS
J23240946), which is remarkable for its strong intermediate-width emission
lines (IELs) with FWHM 1800 \kmps. The IEL component is presented in
different emission lines, including the permitted lines \lya\ 1216,
\civ\ 1549, semiforbidden line \ciii\ 1909, and forbidden
lines \oiii\ 4959, 5007. With the aid of photo-ionization
models, we found that the IELs are produced by gas with a hydrogen density of
, a distance to the central
ionizing source of pc, a covering factor of CF 6\%, and a
dust-to-gas ratio of times of SMC. We suggest that the strong IELs
of this quasar are produced by nearly dust-free and intermediate-density gas
located at the skin of the dusty torus. Such strong IELs, served as a useful
diagnose, can provide an avenue to study the properties of gas between the BELR
and the NELR
Joint Extraction of Entities and Relations Based on a Novel Tagging Scheme
Joint extraction of entities and relations is an important task in
information extraction. To tackle this problem, we firstly propose a novel
tagging scheme that can convert the joint extraction task to a tagging problem.
Then, based on our tagging scheme, we study different end-to-end models to
extract entities and their relations directly, without identifying entities and
relations separately. We conduct experiments on a public dataset produced by
distant supervision method and the experimental results show that the tagging
based methods are better than most of the existing pipelined and joint learning
methods. What's more, the end-to-end model proposed in this paper, achieves the
best results on the public dataset
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