6,726 research outputs found
A reversal coarse-grained analysis with application to an altered functional circuit in depression
Introduction:
When studying brain function using functional magnetic resonance imaging (fMRI) data containing tens of thousands of voxels, a coarse-grained approach – dividing the whole brain into regions of interest – is applied frequently to investigate the organization of the functional network on a relatively coarse scale. However, a coarse-grained scheme may average out the fine details over small spatial scales, thus rendering it difficult to identify the exact locations of functional abnormalities.
Methods:
A novel and general approach to reverse the coarse-grained approach by locating the exact sources of the functional abnormalities is proposed.
Results:
Thirty-nine patients with major depressive disorder (MDD) and 37 matched healthy controls are studied. A circuit comprising the left superior frontal gyrus (SFGdor), right insula (INS), and right putamen (PUT) exhibit the greatest changes between the patients with MDD and controls. A reversal coarse-grained analysis is applied to this circuit to determine the exact location of functional abnormalities.
Conclusions:
The voxel-wise time series extracted from the reversal coarse-grained analysis (source) had several advantages over the original coarse-grained approach: (1) presence of a larger and detectable amplitude of fluctuations, which indicates that neuronal activities in the source are more synchronized; (2) identification of more significant differences between patients and controls in terms of the functional connectivity associated with the sources; and (3) marked improvement in performing discrimination tasks. A software package for pattern classification between controls and patients is available in Supporting Information
Information technology issues in China
In this chapter, we provide important information technology (IT) issues in China, such as organizational IT issues, technology issues, and individual issues. In the World IT Project survey, we recruited 310 IT workers in China. Most of the respondents were in their early career and worked full time in China's IT organizations. The findings show that the most important IT-related organizational issues are: IT reliability and efficiency, security and privacy, and IT strategic planning. Among technology issues, IT professionals identified the following issues as the top concerns: networks/telecommunications, big data systems, data mining, software as a service, and business intelligence/analytics. Most IT employees seem to be satisfied with their current jobs and felt a sense of accomplishment at work. Results further show that more than half of the IT workers would not change their jobs in the short term and felt secure in their current jobs. In addition, there were no significant work-life conflicts among the surveyed IT employees. © 2020 The Author(s)
Understanding the processes observed by Belle
We calculate the production cross sections for ,
and in annihilation through one virtual photon in the
framework of perturbative QCD with constituent quarks. The calculated cross
sections for and production are roughly in agreement
with the recent Belle data. The helicity decomposition for meson
production is also calculated. The fraction of the final
state in process is found to be 65%. The fraction of
production is 100% and is forbidden in annihilation
through one virtual photon. We further consider annihilation through
two virtual photons, and then find the fraction of in process to be about 91%.Comment: 8 pages, 2 figure
Simultaneously Optimizing Perturbations and Positions for Black-box Adversarial Patch Attacks
Adversarial patch is an important form of real-world adversarial attack that
brings serious risks to the robustness of deep neural networks. Previous
methods generate adversarial patches by either optimizing their perturbation
values while fixing the pasting position or manipulating the position while
fixing the patch's content. This reveals that the positions and perturbations
are both important to the adversarial attack. For that, in this paper, we
propose a novel method to simultaneously optimize the position and perturbation
for an adversarial patch, and thus obtain a high attack success rate in the
black-box setting. Technically, we regard the patch's position, the
pre-designed hyper-parameters to determine the patch's perturbations as the
variables, and utilize the reinforcement learning framework to simultaneously
solve for the optimal solution based on the rewards obtained from the target
model with a small number of queries. Extensive experiments are conducted on
the Face Recognition (FR) task, and results on four representative FR models
show that our method can significantly improve the attack success rate and
query efficiency. Besides, experiments on the commercial FR service and
physical environments confirm its practical application value. We also extend
our method to the traffic sign recognition task to verify its generalization
ability.Comment: Accepted by TPAMI 202
The strong vertices of charmed mesons , and charmonia ,
In this work, the strong form factors and coupling constants of the vertices
, , , ,
are calculated within the framework of the QCD sum rule.
For each vertex, we analyze the form factor considering all possible off-shell
cases and the contributions of the vacuum condensate terms
, ,
, and
. Then, the form
factors are fitted into analytical functions and are extrapolated into
time-like regions to get the strong coupling constants. Finally, the strong
coupling constants are obtained by using on-shell cases of the intermediate
mesons(). The results are as follows,
,
GeV,
,
and
GeV
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