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RISS 인기검색어
- 검색키워드
- 저자 : ( Wenbo Mei ) (검색결과 3 건)
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Group-Sparse Channel Estimation using Bayesian Matching Pursuit for OFDM Systems
( Yi Liu ),( Wenbo Mei ),( Huiqian Du ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.2
We apply the Bayesian matching pursuit (BMP) algorithm to the estimation of time-frequency selective channels in orthogonal frequency division multiplexing (OFDM) systems. By exploiting prior statistics and sparse characteristics of propagation channels, the Bayesian method provides a more accurate and efficient detection of the channel status information (CSI) than do conventional sparse channel estimation methods that are based on compressive sensing (CS) technologies. Using a reasonable approximation of the system model and a skillfully designed pilot arrangement, the proposed estimation scheme is able to address the Doppler-induced inter-carrier interference (ICI) with a relatively low complexity. Moreover, to further reduce the computational cost of the channel estimation, we make some modifications to the BMP algorithm. The modified algorithm can make good use of the group-sparse structure of doubly selective channels and thus reconstruct the CSI more efficiently than does the original BMP algorithm, which treats the sparse signals in the conventional manner and ignores the specific structure of their sparsity patterns. Numerical results demonstrate that the proposed Bayesian estimation has a good performance over rapidly time-varying channels.
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Fan Chen,Guojian Mei,Bo Zhao,Wenbo Bie,Guangxi Li 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.1
Three-dimensional (3D) ultrasonic vibration-assisted ELID grinding, which combines 3D ultrasonic vibration-assistance with electrolytic in-process grinding wheel dressing (ELID), is a compound process that is designed to achieve high-efficiency precision machining. A grinding force model of 3D ultrasonic vibration-assisted ELID grinding was first developed on the basis of the kinematics of a single grit particle and was verified through experimentation. The surface quality then was observed using white light interference profiling. It was demonstrated during the present investigation that the grinding force during 3D ultrasonic vibration-assisted ELID grinding was approximately 20 %~30 % lower than that of twodimensional (2D) ultrasonic vibration-assisted ELID grinding. In addition, the surface roughness (Ra) achieved during 3D ultrasonic vibration-assisted ELID grinding was approximately 40 %~50 % smoother than was achieved under 2D ultrasonic vibration-assisted ELID, and thus 3D ultrasonic vibration-assisted ELID grinding can achieve better surface quality.
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Li Cui,Weiquan Bu,Jie Song,Liang Feng,Tingting Xu,Dan Liu,Wenbo Ding,Jianhua Wang,Changyang Li,Binge Ma,Yi Luo,Ziyu Jiang,Chengcheng Wang,Juan Chen,Jian Hou,Hong-mei Yan,Lei Yang,Xiao-bin Jia 대한약학회 2018 Archives of Pharmacal Research Vol.41 No.3
Alantolactone is a sesquiterpene lactone isolatedfrom Inula helenium L. Although alantolactone possessesanti-inflammation and apoptosis-induction activities, theunderlying mechanism of anti-cancer effect on humanbreast cancer cells remains largely unknown. In this study,we explored the possibility of alantolactone as an apoptosis-inducing cytotoxic agent using MDA-MB-231 cells asin vitro model. Alantolactone significantly induced itsapoptosis, demonstrated by cell cycle analysis, annexinV-APC/7-AAD double staining and dUTP nick end labeling. Additionally, alantolactone triggered the mitochondrial-mediated caspase cascade apoptotic pathway, whichwas confirmed by increased Bax/Bcl-2 ratio, loss of MMP,release of cytc from mitochondria to cytoplasm, activationof caspase 9/3, and subsequent cleavage of PARP. Z-VADFMKpartially prevented apoptosis induced by alantolactone. Alantolactone provoked the production of ROS, whileNAC (a scavenger of ROS) reversed alantolactone-mediateddepolarization of MMP and apoptosis. Alantolactonemodulated the activities of MAPKs. As expected, cotreatmentwith SB203580, SP600125 or U0126 could reducedthe apoptotic rate. Furthermore, alantolactone decreasedthe protein expressions of p-NF-kB p65 and p-STAT3,increased p-c-Jun level in a dose-dependent manner. Thesefindings suggested that alantolactone possessed anticanceractivity via ROS-mediated mitochondrial dysfunctioninvolving MAPK pathway, and had an effect on the transcriptionfactors of NF-kB, AP-1 and STAT3.
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