9,939 research outputs found
Structure and Properties of Dense Silica Glass
The O K-edge x-ray Raman scattering (XRS), Brillouin scattering and diffraction studies on silica glass at high pressure have been elucidated in a unified manner using model structures obtained from First-Principles molecular dynamics calculations. This study provides a comprehensive understanding on how the structure is related to the physical and electronic properties. The origin of the "two peak" pattern in the XRS is found to be the result of increased packing of oxygen near the Si and is not a specific sign for sixfold coordination. The compression mechanism involving the presence of 5- and 6-fold coordinated silicon is confirmed. A slight increase in the silicon-oxygen coordination higher than six was found to accompany the increase in the acoustic wave velocity near 140 GPa
Ariadne's Thread:Using Text Prompts to Improve Segmentation of Infected Areas from Chest X-ray images
Segmentation of the infected areas of the lung is essential for quantifying
the severity of lung disease like pulmonary infections. Existing medical image
segmentation methods are almost uni-modal methods based on image. However,
these image-only methods tend to produce inaccurate results unless trained with
large amounts of annotated data. To overcome this challenge, we propose a
language-driven segmentation method that uses text prompt to improve to the
segmentation result. Experiments on the QaTa-COV19 dataset indicate that our
method improves the Dice score by 6.09% at least compared to the uni-modal
methods. Besides, our extended study reveals the flexibility of multi-modal
methods in terms of the information granularity of text and demonstrates that
multi-modal methods have a significant advantage over image-only methods in
terms of the size of training data required.Comment: Provisional Acceptance by MICCAI 202
Ultrasonication improves the structures and physicochemical properties of Cassava starch films containing acetic acid
Cassava starch films are fabricated with acetic acid treatment and ultrasonication. Different ultrasound power levels from 200 to 750 W are used and the effects of ultrasonication on the morphology, microstructures, and properties of the starch–acetic acid films are investigated. Scanning electron microscopy shows a cohesive and compact structure of the films resulting from ultrasonication. X‐ray diffraction analysis reveals that the crystalline index is decreased by acid treatment and increased by ultrasonication. The tensile strength and elongation at break of the films first increase and then decrease with increasing ultrasound power level. Ultrasonication also results in higher opacity, higher water barrier performance, and lower water adsorption of the films. Thus, the results show that ultrasonication can be used as a simple and efficient way to modify the morphology, microstructure, and performance of starch–acetic acid films to better meet the application needs
Iterative distributed minimum total-MSE approach for secure communications in MIMO interference channels
In this paper, we consider the problem of joint transmit precoding (TPC) matrix and receive filter matrix design subject to both secrecy and per-transmitter power constraints in the MIMO interference channel, where K legitimate transmitter-receiver pairs communicate in the presence of an external eavesdropper. Explicitly, we jointly design the TPC and receive filter matrices based on the minimum total mean-squared error (MT-MSE) criterion under a given and feasible information-theoretic degrees of freedom. More specifically, we formulate this problem by minimizing the total MSEs of the signals communicated between the legitimate transmitter-receiver pairs, whilst ensuring that the MSE of the signals decoded by the eavesdropper remains higher than a certain threshold. We demonstrate that the joint design of the TPC and receive filter matrices subject to both secrecy and transmit power constraints can be accomplished by an efficient iterative distributed algorithm. The convergence of the proposed iterative algorithm is characterized as well. Furthermore, the performance of the proposed algorithm, including both its secrecy rate and MSE, is characterized with the aid of numerical results. We demonstrate that the proposed algorithm outperforms the traditional interference alignment (IA) algorithm in terms of both the achievable secrecy rate and the MSE. As a benefit, secure communications can be guaranteed by the proposed algorithm for the MIMO interference channel even in the presence of a "sophisticated/strong" eavesdropper, whose number of antennas is much higher than that of each legitimate transmitter and receiver
Improved belief propagation decoding algorithm based on decoupling representation of Pauli operators for quantum LDPC codes
We propose a new method called decoupling representation to represent Pauli
operators as vectors over GF(2), based on which we propose partially decoupled
belief propagation and fully decoupled belief propagation decoding algorithm
for quantum low density parity-check codes. Under the assumption that there is
no measurement error, compared with traditional belief propagation algorithm in
symplectic representation over GF(2), within the same number of iterations, the
decoding accuracy of partially decoupled belief propagation and fully decoupled
belief propagation algorithm is significantly improved in pure Y noise channel
and depolarizing noise channel, which supports that decoding algorithms of
quantum error correcting codes might have better performance in decoupling
representation than in symplectic representation. The impressive performance of
fully decoupled belief propagation algorithm might promote the realization of
quantum error correcting codes in engineering
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