3,512 research outputs found
Optimal Entanglement Transformations Among N-qubit W-Class States
We investigate the physically allowed probabilities for transforming one
N-partite W-class state to another by means of local operations assisted with
classical communication (LOCC). Recently, Kintas and Turgut have obtained an
upper bound for the maximum probability of transforming two such states
[arXiv:1003.2118v1]. Here, we provide a simple sufficient and necessary
condition for when this upper bound can be satisfied and thus when optimality
of state transformation can be achieved. Our discussion involves obtaining
lower bounds for the transformation of arbitrary W-class states and showing
precisely when this bound saturates the bound of [arXiv:1003.2118v1]. Finally,
we consider the question of transforming symmetric W-class states and find that
in general, the optimal one-shot procedure for converting two symmetric states
requires a non-symmetric filter by all the parties
Analysis of Hydrogen Cyanide Hyperfine Spectral Components towards Star Forming Cores
Although hydrogen cyanide has become quite a common molecular tracing species
for a variety of astrophysical sources, it, however, exhibits dramatic non-LTE
behaviour in its hyperfine line structure. Individual hyperfine components can
be strongly boosted or suppressed. If these so-called hyperfine line anomalies
are present in the HCN rotational spectra towards low or high mass cores, this
will affect the interpretation of various physical properties such as the line
opacity and excitation temperature in the case of low mass objects and infall
velocities in the case of their higher mass counterparts. This is as a
consequence of the direct effects that anomalies have on the underlying line
shape, be it with the line structural width or through the inferred line
strength. This work involves the first observational investigation of these
anomalies in two HCN rotational transitions, J=1!0 and J=3!2, towards both low
mass starless cores and high mass protostellar objects. The degree of anomaly
in these two rotational transitions is considered by computing the ratios of
neighboring hyperfine lines in individual spectra. Results indicate some degree
of anomaly is present in all cores considered in our survey, the most likely
cause being line overlap effects among hyperfine components in higher
rotational transitions.Comment: 8th Serbian Conference on Spectral Line Shapes in Astrophysics,
Divicibare; 8 pages, 5 figure
A framework for efficient regression tests on database applications
Regression testing is an important software maintenance activity to ensure the integrity of a software after modification. However, most methods and tools developed for software testing today do not work well for database applications; these tools only work well if applications are stateless or tests can be designed in such a way that they do not alter the state. To execute tests for database applications efficiently, the challenge is to control the state of the database during testing and to order the test runs such that expensive database reset operations that bring the database into the right state need to be executed as seldom as possible. This work devises a regression testing framework for database applications so that test runs can be executed in parallel. The goal is to achieve linear speed-up and/or exploit the available resources as well as possible. This problem is challenging because parallel testing needs to consider both load balancing and controlling the state of the database. Experimental results show that test run execution can achieve linear speed-up by using the proposed framewor
High Performance Depthwise and Pointwise Convolutions on Mobile Devices
Lightweight convolutional neural networks (e.g., MobileNets) are specifically
designed to carry out inference directly on mobile devices. Among the various
lightweight models, depthwise convolution (DWConv) and pointwise convolution
(PWConv) are their key operations. In this paper, we observe that the existing
implementations of DWConv and PWConv are not well utilizing the ARM processors
in the mobile devices, and exhibit lots of cache misses under multi-core and
poor data reuse at register level. We propose techniques to re-optimize the
implementations of DWConv and PWConv based on ARM architecture. Experimental
results show that our implementation can respectively achieve a speedup of up
to 5.5x and 2.1x against TVM (Chen et al. 2018) on DWConv and PWConv.Comment: 8 pages, Thirty-Four AAAI conference on Artificial Intelligenc
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