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4,936 results on '"Liu, Hongbo"'

63. Pathogenic bacteria and treatment resistance in older cardiovascular disease patients with lung infection and risk prediction model

Author

Liu Hongbo, Xie Liyan, and Xing Cong

Subjects
cardiovascular disease, pulmonary infection, pathogenic bacteria, drug resistance, risk prediction model, Biology (General), QH301-705.5
Abstract

This study analyzes the distribution of pathogenic bacteria and their antimicrobial susceptibilities in elderly patients with cardiovascular diseases to identify risk factors for pulmonary infections. A risk prediction model is established, aiming to serve as a clinical tool for early prevention and management of pulmonary infections in this vulnerable population. A total of 600 patients were categorized into infected and uninfected groups. Independent risk factors such as older age, diabetes history, hypoproteinemia, invasive procedures, high cardiac function grade, and a hospital stay of ≥10 days were identified through logistic regression. A predictive model was constructed, with a Hosmer–Lemeshow goodness of fit (P = 0.236) and an area under the receiver operating characteristic curve of 0.795, demonstrating good discriminative ability. The model had 63.40% sensitivity and 82.80% specificity, with a cut-off value of 0.13. Our findings indicate that the risk score model is valid for identifying high-risk groups for pulmonary infection among elderly cardiovascular patients. The study contributes to the early prevention and control of pulmonary infections, potentially reducing infection rates in this vulnerable population.

Published
2023
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64. Removal mechanism of Hydroides fouling on high-strength steel in the marine environment during nanosecond pulsed laser cleaning

Author

Bi Siyuan, Yang Shuo, Liu Hongbo, and Lei Zhenglong

Subjects
Laser cleaning, Hydroides fouling, High-strength steel, Removal mechanism, Spectral analysis, Acoustic signal analysis, Mining engineering. Metallurgy, TN1-997
Abstract

The surface of metal materials will be contaminated by marine organisms when serving in the marine environment, which seriously affects the service life of the materials, and must be cleaned regularly. The Hydroides fouling on the surface of 30Cr3 high-strength steel was taken as the object to be cleaned; the cleaning quality at different laser fluences was studied; the desorption behavior and the characteristics of spectral and acoustic signals during laser cleaning were analyzed; and the removal mechanism of Hydroides fouling on the surface of high-strength steel was summarized. The results show that the cleaning effect of nanosecond pulsed laser on Hydroides fouling increases with the increase of laser fluence, and the laser fluence of 9.95 J/cm2 can be used to clean the Hydroides fouling with the maximum diameter of 1.62 mm completely with little damage to the substrate. The removal mechanism of Hydroides fouling is the inverse bremsstrahlung mechanism. In the process of cleaning, the surface fouling is partially vaporized and ionized into high-temperature plasma under the action of pulsed laser. The laser energy is absorbed through inverse bremsstrahlung absorption to form shock waves to compress the surface, which leads to cracks on Hydroides fouling. When the surface compressive stress is released, the Hydroides fouling is removed from the surface, and the removal effect increases with the increase of laser fluence.

Published
2023
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65. Fast and Secure Key Generation with Channel Obfuscation in Slowly Varying Environments

Author

Li, Guyue, Yang, Haiyu, Zhang, Junqing, Liu, Hongbo, and Hu, Aiqun

Subjects
Computer Science - Cryptography and Security, Computer Science - Information Theory
Abstract

The physical-layer secret key generation has emerged as a promising solution for establishing cryptographic keys by leveraging reciprocal and time-varying wireless channels. However, existing approaches suffer from low key generation rates and vulnerabilities under various attacks in slowly varying environments. We propose a new physical-layer secret key generation approach with channel obfuscation, which improves the dynamic property of channel parameters based on random filtering and random antenna scheduling. Our approach makes one party obfuscate the channel to allow the legitimate party to obtain similar dynamic channel parameters yet prevents a third party from inferring the obfuscation information. Our approach allows more random bits to be extracted from the obfuscated channel parameters by a joint design of the K-L transform and adaptive quantization. A testbed implementation shows that our approach, compared to the existing ones that we evaluate, performs the best in generating high entropy bits at a fast rate and a high-security level in slowly varying environments. Specifically, our approach can achieve a significantly faster secret bit generation rate at about $67$ bit/pkt, and the key sequences can pass the randomness tests of the NIST test suite.

Published
2021

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