354 research outputs found
Real-time Optimal Resource Allocation for Embedded UAV Communication Systems
We consider device-to-device (D2D) wireless information and power transfer
systems using an unmanned aerial vehicle (UAV) as a relay-assisted node. As the
energy capacity and flight time of UAVs is limited, a significant issue in
deploying UAV is to manage energy consumption in real-time application, which
is proportional to the UAV transmit power. To tackle this important issue, we
develop a real-time resource allocation algorithm for maximizing the energy
efficiency by jointly optimizing the energy-harvesting time and power control
for the considered (D2D) communication embedded with UAV. We demonstrate the
effectiveness of the proposed algorithms as running time for solving them can
be conducted in milliseconds.Comment: 11 pages, 5 figures, 1 table. This paper is accepted for publication
on IEEE Wireless Communications Letter
Joint Fractional Time Allocation and Beamforming for Downlink Multiuser MISO Systems
It is well-known that the traditional transmit beamforming at a base station
(BS) to manage interference in serving multiple users is effective only when
the number of users is less than the number of transmit antennas at the BS.
Non-orthogonal multiple access (NOMA) can improve the throughput of users with
poorer channel conditions by compromising their own privacy because other users
with better channel conditions can decode the information of users in poorer
channel state. NOMA still prefers that the number of users is less than the
number of antennas at the BS transmitter. This paper resolves such issues by
allocating separate fractional time slots for serving the users with similar
channel conditions. This enables the BS to serve more users within the time
unit while the privacy of each user is preserved. The fractional times and
beamforming vectors are jointly optimized to maximize the system's throughput.
An efficient path-following algorithm, which invokes a simple convex quadratic
program at each iteration, is proposed for the solution of this challenging
optimization problem. Numerical results confirm its versatility.Comment: IEEE Communications Letters (To Appear
Accounting conservatism and banking expertise on board of directors
Previous studies show mixed evidence of the role of banking expertise on the board of directors on accounting conservatism. In this paper, we add to this growing literature by providing an innovative way to measure banking expertise based on life-time working history in banks of all individual directors on the board. We find that accounting conservatism is negatively affected by banking expertise on the board. Also, the results indicate that banking expertise on the board has a more pronounced impact on accounting conservatism when firms have high bankruptcy risk and when firms have high financial leverage. The evidence has some implications for boards of directors
Advancing Wound Filling Extraction on 3D Faces: A Auto-Segmentation and Wound Face Regeneration Approach
Facial wound segmentation plays a crucial role in preoperative planning and
optimizing patient outcomes in various medical applications. In this paper, we
propose an efficient approach for automating 3D facial wound segmentation using
a two-stream graph convolutional network. Our method leverages the Cir3D-FaIR
dataset and addresses the challenge of data imbalance through extensive
experimentation with different loss functions. To achieve accurate
segmentation, we conducted thorough experiments and selected a high-performing
model from the trained models. The selected model demonstrates exceptional
segmentation performance for complex 3D facial wounds. Furthermore, based on
the segmentation model, we propose an improved approach for extracting 3D
facial wound fillers and compare it to the results of the previous study. Our
method achieved a remarkable accuracy of 0.9999986\% on the test suite,
surpassing the performance of the previous method. From this result, we use 3D
printing technology to illustrate the shape of the wound filling. The outcomes
of this study have significant implications for physicians involved in
preoperative planning and intervention design. By automating facial wound
segmentation and improving the accuracy of wound-filling extraction, our
approach can assist in carefully assessing and optimizing interventions,
leading to enhanced patient outcomes. Additionally, it contributes to advancing
facial reconstruction techniques by utilizing machine learning and 3D
bioprinting for printing skin tissue implants. Our source code is available at
\url{https://github.com/SIMOGroup/WoundFilling3D}
Robust Beamforming for Secrecy Rate in Cooperative Cognitive Radio Multicast Communications
In this paper, we propose a cooperative approach to improve the security of
both primary and secondary systems in cognitive radio multicast communications.
During their access to the frequency spectrum licensed to the primary users,
the secondary unlicensed users assist the primary system in fortifying security
by sending a jamming noise to the eavesdroppers, while simultaneously protect
themselves from eavesdropping. The main objective of this work is to maximize
the secrecy rate of the secondary system, while adhering to all individual
primary users' secrecy rate constraints. In the case of passive eavesdroppers
and imperfect channel state information knowledge at the transceivers, the
utility function of interest is nonconcave and involved constraints are
nonconvex, and thus, the optimal solutions are troublesome. To address this
problem, we propose an iterative algorithm to arrive at a local optimum of the
considered problem. The proposed iterative algorithm is guaranteed to achieve a
Karush-Kuhn-Tucker solution.Comment: 6 pages, 4 figures, IEEE ICC 201
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