34,407 research outputs found
Investigate the interaction between dark matter and dark energy
In this paper we investigate the interaction between dark matter and dark
energy by considering two different interacting scenarios, i.e. the cases of
constant interaction function and variable interaction function. By fitting the
current observational data to constrain the interacting models, it is found
that the interacting strength is non-vanishing, but weak for the case of
constant interaction function, and the interaction is not obvious for the case
of variable interaction function. In addition, for seeing the influence from
interaction we also investigate the evolutions of interaction function,
effective state parameter for dark energy and energy density of dark matter. At
last some geometrical quantities in the interacting scenarios are discussed.Comment: 14 pages, 6 figure
The kHz QPOs as a probe of the X-ray color-color diagram and accretion-disk structure for the atoll source 4U 1728-34
We have taken the kHz QPOs as a tool to probe the correlation between the
tracks of X-ray color-color diagram (CCD) and magnetosphere-disk positions for
the atoll source 4U 1728-34, based on the assumptions that the upper kHz QPO is
ascribed to the Keplerian orbital motion and the neutron star (NS)
magnetosphere is defined by the dipole magnetic field. We find that from the
island to the banana state, the inner accretion disk gradually approaches the
NS surface with the radius decreasing from r ~33.0km to ~15.9 km, corresponding
to the magnetic field from B(r) ~4.8*10^6 G to ~4.3*10^7 G. In addition, we
note the characteristics of some particular radii of magnetosphere-disk -r are:
firstly, the whole atoll shape of the CCD links the disk radius range of ~15.9
- 33.0 km, which is just located inside the corotation radius of 4U 1728-34
-r_co ( ~34.4 km), implying that the CCD shape is involved in the NS spin-up
state. Secondly, the island and banana states of CCD correspond to the two
particular boundaries: (I)-near the corotation radius at r ~27.2 - 33.0 km,
where the source lies in the island state; (II)-near the NS surface at r ~15.9
- 22.3 km, where the source lies in both the island and banana states. Thirdly,
the vertex of the atoll shape in CCD, where the radiation transition from the
hard to soft photons occurs, is found to be near the NS surface at r ~16.4 km.
The above results suggest that both the magnetic field and accretion
environment are related to the CCD structure of atoll track, where the
corotation radius and NS hard surface play the significant roles in the
radiation distribution of atoll source.Comment: 6 pages, 3 figures, 1 table, accepted by Astronomy & Astrophysic
Convolutional Neural Networks over Tree Structures for Programming Language Processing
Programming language processing (similar to natural language processing) is a
hot research topic in the field of software engineering; it has also aroused
growing interest in the artificial intelligence community. However, different
from a natural language sentence, a program contains rich, explicit, and
complicated structural information. Hence, traditional NLP models may be
inappropriate for programs. In this paper, we propose a novel tree-based
convolutional neural network (TBCNN) for programming language processing, in
which a convolution kernel is designed over programs' abstract syntax trees to
capture structural information. TBCNN is a generic architecture for programming
language processing; our experiments show its effectiveness in two different
program analysis tasks: classifying programs according to functionality, and
detecting code snippets of certain patterns. TBCNN outperforms baseline
methods, including several neural models for NLP.Comment: Accepted at AAAI-1
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