1,009 research outputs found
The Status and Prospects of Community Education Workers in China
Professionalization, career development prospects, and social value are the three basic components of the status and prospects of community education workers, which influence their choice to continue their careers or not. In China, these problems are complex and lacking in systematic research, and the current situation does not meet the needs of community education. This study interviewed 24 community workers regarding their salaries, working conditions, and training and career advancement opportunities to evaluate this situation in Ningbo City. The findings highlight challenges in the evaluation processes and work motivations of community education workers, including teams without professional knowledge, lack of training opportunities, unsupportive policies, and low salaries. These findings can be used by governments and community workers to find collaborative ways to facilitate community education processes, including the provision of adult education for community educators. New legal policies to raise the status of community educators are also suggested
3D Medical Image Segmentation based on multi-scale MPU-Net
The high cure rate of cancer is inextricably linked to physicians' accuracy
in diagnosis and treatment, therefore a model that can accomplish
high-precision tumor segmentation has become a necessity in many applications
of the medical industry. It can effectively lower the rate of misdiagnosis
while considerably lessening the burden on clinicians. However, fully automated
target organ segmentation is problematic due to the irregular stereo structure
of 3D volume organs. As a basic model for this class of real applications,
U-Net excels. It can learn certain global and local features, but still lacks
the capacity to grasp spatial long-range relationships and contextual
information at multiple scales. This paper proposes a tumor segmentation model
MPU-Net for patient volume CT images, which is inspired by Transformer with a
global attention mechanism. By combining image serialization with the Position
Attention Module, the model attempts to comprehend deeper contextual
dependencies and accomplish precise positioning. Each layer of the decoder is
also equipped with a multi-scale module and a cross-attention mechanism. The
capability of feature extraction and integration at different levels has been
enhanced, and the hybrid loss function developed in this study can better
exploit high-resolution characteristic information. Moreover, the suggested
architecture is tested and evaluated on the Liver Tumor Segmentation Challenge
2017 (LiTS 2017) dataset. Compared with the benchmark model U-Net, MPU-Net
shows excellent segmentation results. The dice, accuracy, precision,
specificity, IOU, and MCC metrics for the best model segmentation results are
92.17%, 99.08%, 91.91%, 99.52%, 85.91%, and 91.74%, respectively. Outstanding
indicators in various aspects illustrate the exceptional performance of this
framework in automatic medical image segmentation.Comment: 37 page
Deforming black holes with even multipolar differential rotation boundary
Motivated by the novel asymptotically global AdS solutions with deforming
horizon in [JHEP {\bf 1802}, 060 (2018)], we analyze the boundary metric with
even multipolar differential rotation and numerically construct a family of
deforming solutions with quadrupolar differential rotation boundary, including
two classes of solutions: solitons and black holes. In contrast to solutions
with dipolar differential rotation boundary, we find that even though the norm
of Killing vector becomes spacelike for certain regions of polar
angle when , solitons and black holes with quadrupolar
differential rotation still exist and do not develop hair due to superradiance.
Moreover, at the same temperature, the horizonal deformation of quadrupolar
rotation is smaller than that of dipolar rotation. Furthermore, we also study
the entropy and quasinormal modes of the solutions, which have the analogous
properties to that of dipolar rotation.Comment: 18 pages, 21 figure
Performance analysis and algorithm design for distributed transmit beamforming
Wireless sensor networks has been one of the major research topics in recent years because
of its great potential for a wide range of applications. In some application scenarios, sensor
nodes intend to report the sensing data to a far-field destination, which cannot be realized by
traditional transmission techniques. Due to the energy limitations and the hardware constraints
of sensor nodes, distributed transmit beamforming is considered as an attractive candidate for
long-range communications in such scenarios as it can reduce energy requirement of each sensor
node and extend the communication range. However, unlike conventional beamforming,
which is performed by a centralized antenna array, distributed beamforming is performed by
a virtual antenna array composed of randomly located sensor nodes, each of which has an
independent oscillator. Sensor nodes have to coordinate with each other and adjust their transmitting
signals to collaboratively act as a distributed beamformer. The most crucial problem of
realizing distributed beamforming is to achieve carrier phase alignment at the destination. This
thesis will investigate distributed beamforming from both theoretical and practical aspects.
First, the bit error ratio performance of distributed beamforming with phase errors is analyzed,
which is a key metric to measure the system performance in practice. We derive two distinct
expressions to approximate the error probability over Rayleigh fading channels corresponding
to small numbers of nodes and large numbers of nodes respectively. The accuracy of both
expressions is demonstrated by simulation results. The impact of phase errors on the system
performance is examined for various numbers of nodes and different levels of transmit power.
Second, a novel iterative algorithm is proposed to achieve carrier phase alignment at the destination
in static channels, which only requires one-bit feedback from the destination. This
algorithm is obtained by combining two novel schemes, both of which can greatly improve the
convergence speed of phase alignment. The advantages in the convergence speed are obtained
by exploiting the feedback information more efficiently compared to existing solutions.
Third, the proposed phase alignment algorithm is modified to track time-varying channels. The
modified algorithm has the ability to detect channel amplitude and phase changes that arise over
time due to motion of the sensors or the destination. The algorithm can adjust key parameters
adaptively according to the changes, which makes it more robust in practical implementation
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