Search

Your search keyword '"QIU Jiahui"' showing total 121 results
Start Over Author "QIU Jiahui"
121 results on '"QIU Jiahui"'

101. An Performance Study for Sectorised Antenna based Doppler Diversity in High-Speed Railway Communications

Author

Liu, Liu, Tao, Cheng, Qiu, Jiahui, and Chen, Houjin

Subjects
High-Speed Railway, ComputerSystemsOrganization_SPECIAL-PURPOSEANDAPPLICATION-BASEDSYSTEMS, Data_CODINGANDINFORMATIONTHEORY, lcsh:Electrical engineering. Electronics. Nuclear engineering, Doppler diversity, sectorised antenna, lcsh:TK1-9971, Computer Science::Information Theory
Abstract

The wireless channel of High-Speed Railway communication system is rapidly time-varying. The orthogonal frequency division multiplexing transmitting over this channel will be exposed to the intercarrier interference caused by large Doppler spread. The sectorised antenna can be employed for Doppler mitigation and obtaining Doppler diversity gain. In this paper the performance of this directional antenna is analyzed. The preferable partition scheme for the omnidirectional antenna and the optimal Doppler compensation frequency are addressed firstly. And the uncorrelated property of the signal received from the different sectorised antennas is demonstrated originally which can be utilized for Doppler diversity gain. Finally, it is proved by the simulation results that this architecture will allows us to achieve remarkable performance under high mobility conditions.

Published
2011

102. A Novel OFDM Channel Estimation Algorithm with ICI Mitigation over Fast Fading Channels

Author

Tao, Cheng, Qiu, Jiahui, and Liu, Liu

Subjects
high-speed mobility, channel estimation, lcsh:Electrical engineering. Electronics. Nuclear engineering, OFDM system, lcsh:TK1-9971, ICI mitigation
Abstract

Orthogonal frequency-division multiplexing (OFDM) is well-known as a high-bit-rate transmission technique, but the Doppler frequency offset due to the high speed movement destroys the orthogonality of the subcarriers resulting in the intercarrier interference (ICI), and degrades the performance of the system at the same time. In this paper a novel OFDM channel estimation algorithm with ICI mitigation based on the ICI self-cancellation scheme is proposed. With this method, a more accurate channel estimation is obtained by comb-type double pilots and then ICI coefficients can be obtained to mitigate the ICI on each subcarrier under the assumption that the channel impulse response (CIR) varies in a linear fashion. The theoretical analysis and simulation results show that the bit error rate (BER) and spectral efficiency performances are improved significantly under high-speed mobility conditions (350 km/h – 500 km/h) in comparison to ZHAO’s ICI self-cancellation scheme.

Published
2010

111. A Novel Comb-Pilot Transform Domain Frequency Diversity Channel Estimation for OFDM System

Author

Liu, Liu, Tao, Cheng, Qiu, Jiahui, Qi, Xiaoyu, Liu, Liu, Tao, Cheng, Qiu, Jiahui, and Qi, Xiaoyu

Abstract

Due to implementation complexity, the transform domain channel estimation based on training symbols or comb-type pilots has been paid more attention because of its efficient algorithm FFT/IFFT. However, in a comb-type OFDM system, the length of the channel impulse response is much smaller than the pilot number. In this case, the comb-pilot transform domain channel estimation only works as interpolation like the Least Squares (LS) algorithm, but loses the noise suppression function. In this paper, we propose a novel frequency diversity channel estimation method via grouped pilots combining. With this estimator, not only the channel frequency response on non-pilot subcarriers can be interpolated, but also the noise can be better suppressed. Moreover, it does not need prior statistical characteristics of the wireless channel.

Published
2009

119. In vitroand in silicoanalysis of a E559K mutation on cartilage oligomeric matrix protein

Author

Qiu, Jiahui and Tan, Jichun

Abstract

Pseudoachondroplasia (PSACH) is known as an autosomal dominant disorder associated with mutations in the gene of cartilage oligomeric matrix protein (COMP). The pathomolecular mechanisms of PSACH as a result of C-terminal globular region (CTD) mutations remain unclear. A heterozygous mutation (E559 K) in a Chinese family diagnosed with PSACH was reported in this study. To understand the pathogenesis of this mutation, we studied chondrogenic differentiation of patient menstrual blood-derived stem cells (MenSCs), and the impact of the mutation on structural changes of COMP was investigated using all-atom molecular dynamics simulation. The results suggested that the interactions with calcium and other molecules in the mutant structure were affected resulting in misfolding of the protein, which leads to ER stress and finally affects the survival of chondrocytes. The findings may promote the understanding of the pathomolecular mechanisms of PSACH, and possibly the development of drugs to treat the disease.

Published
2022
Full Text
View/download PDF

121. A Cytochrome B 5 -Like Heme/Steroid Binding Domain Protein, PlCB5L1, Regulates Mycelial Growth, Pathogenicity and Oxidative Stress Tolerance in Peronophythora litchii .

Author

Li W, Li P, Zhou X, Situ J, Lin Y, Qiu J, Yuan Y, Xi P, Jiang Z, and Kong G

Abstract

As an electron transport component, cytochrome b 5 is an essential component of the Class II cytochrome P450 monooxygenation system and widely present in animals, plants, and fungi. However, the roles of Cyt-b 5 domain proteins in pathogenic oomycetes remain unknown. Peronophythora litchii is an oomycete pathogen that causes litchi downy blight, the most destructive disease of litchi. In this study, we identified a gene, designated PlCB5L1 , that encodes a Cyt-b 5 domain protein in P . litchii , and characterized its function. PlCB5L1 is highly expressed in the zoospores, cysts, germinated cysts, and during early stages of infection. PlCB5L1 knockout mutants showed reduced growth rate and β-sitosterol utilization. Importantly, we also found that PlCB5L1 is required for the full pathogenicity of P . litchii . Compared with the wild-type strain, the PlCB5L1 mutants exhibited significantly higher tolerance to SDS and sorbitol, but impaired tolerance to cell wall stress, osmotic stress, and oxidative stress. Further, the expression of genes involved in oxidative stress tolerance, including peroxidase, cytochrome P450, and laccase genes, were down-regulated in PlCB5L1 mutants under oxidative stress. This is the first report that a Cyt-b 5 domain protein contributes to the development, stress response, and pathogenicity in plant pathogenic oomycetes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Li, Li, Zhou, Situ, Lin, Qiu, Yuan, Xi, Jiang and Kong.)

Published
2021
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results