Sensing of OFDM Signals in Cognitive Radio Systems with Time Domain Cross-Correlation

Weiyang Xu 한국전자통신연구원 2014 ETRI Journal Vol.36 No.4

This paper proposes an algorithm to sense orthogonalfrequency-division multiplexing (OFDM) signals incognitive radio (CR) systems. The basic idea behind thisstudy is when a primary user is occupying a wirelesschannel, the covariance matrix is non-diagonal because ofthe time domain cross-correlation of the cyclic prefix (CP). In light of this property, a new decision metric thatmeasures the power of the data found on two minordiagonals in the covariance matrix related to the CP isintroduced. The impact of synchronization errors on thesignal detection is analyzed. Besides this, a likelihood-ratiotest is proposed according to the Neyman–Pearsoncriterion after deriving probability distribution functionsof the decision metric under hypotheses of signal presenceand absence. A threshold, subject to the requirement ofprobability of false alarm, is derived; also the probabilitiesof detection and false alarm are computed accordingly. Finally, numerical simulations are conducted todemonstrate the effectiveness of the proposed algorithm.

Neural Network Model for the Risk Prediction in Cold Chain Logistics

Weiyang Xu,Zhenji Zhang,Daqing Gong,Xiaolan Guan 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.8

AbSte7, a MAPKK Gene of Alternaria brassicicola, Is Involved in Conidiation, Salt/Oxidative Stress, and Pathogenicity

Xu, Houjuan,Zhang, Qianqian,Cui, Wenjuan,Zhang, Xiaofei,Liu, Weiyang,Zhang, Li,Islam, Md. Nurul,Baek, Kwang-Hyun,Wang, Yujun The Korean Society for Microbiology and Biotechnol 2016 Journal of microbiology and biotechnology Vol.26 No.7

Alternaria brassicicola (Schwein.) invades Brassicaceae and causes black spot disease, significantly lowering productivity. Mitogen-activated protein kinases (MAPKs) and their upstream kinases, including MAPK kinases (MAPKKs) and MAPKK kinases (MAPKKK), comprise one of the most important signaling pathways determining the pathogenicity of diverse plant pathogens. The AbSte7 gene in the genome of A. brassicicola was predicted to be a homolog of yeast Ste7, a MAPKK; therefore, the function was characterized by generating null mutant strains with a gene replacement method. AbSte7 replacement mutants (RMs) had a slower growth rate and altered colony morphology compared with the wild-type strain. Disruption of the AbSte7 gene resulted in defects in conidiation and melanin accumulation. AbSte7 was also involved in the resistance pathways in salt and oxidative stress, working to negatively regulate salt tolerance and positively regulate oxidative stress. Pathogenicity assays revealed that AbSte7 RMs could not infect intact cabbage leaves, but only formed very small lesions in wounded leaves, whereas typical lesions appeared on both intact and wounded leaves inoculated with the wild-type strain. As the first studied MAPKK in A. brassicicola, these data strongly suggest that the AbSte7 gene is an essential element for the growth, development, and pathogenicity of A. brassicicola.

AbSte7, a MAPKK Gene of Alternaria brassicicola, Is Involved in Conidiation, Salt/Oxidative Stress, and Pathogenicity

( Houjuan Xu ),( Qianqian Zhang ),( Wenjuan Cui ),( Xiaofei Zhang ),( Weiyang Liu ),( Li Zhang ),( Md. Nurul Islam ),( Kwang-hyun Baek ),( Yujun Wang ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.6

Alternaria brassicicola (Schwein.) invades Brassicaceae and causes black spot disease, significantly lowering productivity. Mitogen-activated protein kinases (MAPKs) and their upstream kinases, including MAPK kinases (MAPKKs) and MAPKK kinases (MAPKKK), comprise one of the most important signaling pathways determining the pathogenicity of diverse plant pathogens. The AbSte7 gene in the genome of A. brassicicola was predicted to be a homolog of yeast Ste7, a MAPKK; therefore, the function was characterized by generating null mutant strains with a gene replacement method. AbSte7 replacement mutants (RMs) had a slower growth rate and altered colony morphology compared with the wild-type strain. Disruption of the AbSte7 gene resulted in defects in conidiation and melanin accumulation. AbSte7 was also involved in the resistance pathways in salt and oxidative stress, working to negatively regulate salt tolerance and positively regulate oxidative stress. Pathogenicity assays revealed that AbSte7 RMs could not infect intact cabbage leaves, but only formed very small lesions in wounded leaves, whereas typical lesions appeared on both intact and wounded leaves inoculated with the wild-type strain. As the first studied MAPKK in A. brassicicola, these data strongly suggest that the AbSte7 gene is an essential element for the growth, development, and pathogenicity of A. brassicicola.

IL-17 Imbalance Promotes the Pyroptosis in Immune-Mediated Liver Injury Through STAT3-IFI16 Axis

Wenfang Xu,Yanan Wang,Changzhong Jin,Weiyang Zhang,Jiangnan Chen,Xuefang Chen,Junli Gao,Junshun Gao,Hong Wang 대한면역학회 2023 Immune Network Vol.23 No.6

Autoimmune hepatitis (AIH) affects all age group and occurs mainly in women. Pyroptosis is a novel programmed cell death featured with cell bursting and release of proinflammatory cytokines. A deeper understanding of AIH pathogenesis will contribute to novel therapy for AIH patients. Here, we aimed to investigate the role of IL-17 in immune-mediated liver injury. The levels of cytokines were measured by ELISA, and mRNA levels of STAT3 and IFN gammainducible protein 16 (IFI16) were detected by PCR. Expressions of STAT3, IFI16, gasdermin D and cleaved caspase-1 were measured by western-blotting. Immunohistochemical staining and transmission electron microscopy were applied to evaluate liver histopathological changes of the treated mice. Our results showed that the levels of IFI16 was increased in hepatocytes treated with IL-17 protein, and further elevated after STAT3-overexpressed (STAT3-OE) lentivirus treatment. The levels of IFI16 were reduced in hepatocytes treated with IL-17 neutralizing Ab (nAb), but were significantly increased after STAT3-OE treatment. Pyroptosis was observed in hepatocytes treated with IL-17 protein, and further cell damage was observed after STAT3-OE lentivirus treatment. Liver damage was alleviated in mice treated with IL-17 nAb, however sever damage was experienced after STAT3-OE lentivirus treatment. A binding interaction between IFI16 and STAT3 was detected in IL-17 treated hepatocytes. Glutathione transaminase activity was enhanced in concanavalin A-induced AIH mice compared to the control group (p<0.01). IL-17 plays an important role in activating STAT3 and up-regulating IFI16, which may promote the pyroptosis in AIH-related liver injury through STAT3-IFI16 axis.

NUMERICAL ANALYSIS OF LOW SPEED PRE-IGNITION AND KNOCK PROCESS IN DOWNSIZED TURBOCHARGED DIRECT INJECTION ENGINES WITH ETHANOL-GASOLINE BLENDS

Li Ruichen,Xu Boyan,Qi Yunliang,Xu Weiyang 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.1

The feasibility of the calculation model and calculation methods is verified by engine bench test and visual rapid compression machine (RCM) test as reported in this paper. Using AVL software FIRE, the processes of low speed preignition (LSPI) and super knock triggered by the oil particles have been studied by numerical analysis of downsized turbocharged direct injection (DI) engines with different proportions of ethanol-gasoline blended fuel and different operating conditions (1200 r∙min1, 1600 r∙min1). The results show that the E10 and E20 fuel engines produce super knock successively; with the increase of the ethanol proportion, even if the LSPI phenomenon (1200 r∙min1) still occurs and leads to the subsequent knock process, the pressure rise amplitude is obviously reduced, and no super knock phenomenon occurs at the time when the ethanol proportion reaches 30 %; there is no LSPI phenomenon in the engine after the blending rate is above 50 %. The overall conclusion is that there must be LSPI before the super knock in ethanol-gasoline blended fuel downsized turbocharged DI engines, but the LSPI not always lead to super knock. With the increase of ethanol proportion, even if the LSPI occurs in the engine cylinder, it only causes regular knock.