Due to the problem of spectrum underutilization and energy inefficiency in wireless communications,the research on energy efficient Cognitive Radio Networks (CRNs) has received significant attention in both industry a...Due to the problem of spectrum underutilization and energy inefficiency in wireless communications,the research on energy efficient Cognitive Radio Networks (CRNs) has received significant attention in both industry and academia.In this paper,we consider the problem of optimal spectrum selection and transmission parameters design with the objective of minimizing energy consumption in CRNs.Since the system state cannot be directly observed due to miss detections and estimation errors,we formulate the optimal spectrum access problem as a Partially Observable Markov Decision Process (POMDP).In particular,the proposed scheme selects the optimal spectrum,modulation and coding scheme,transmission power,and link layer frame size in each time slot according to the belief state,which captures all the history information of past actions and observations.The optimal policy can be acquired by solving POMDP problem with linear programming based algorithm.Simulation results show that significant energy savings can be achieved by the proposed scheme.展开更多
目的探讨基因预测软件Targetscan预测到的微小RNA-130a如何调节GTP酶激活蛋白SH3功能区结合蛋白2(GTPase activating protein SH3 binding protein 2,G3BP2)的表达,进而影响乳腺癌细胞的侵袭。方法应用实时荧光定量PCR(qRT-PCR)检测正...目的探讨基因预测软件Targetscan预测到的微小RNA-130a如何调节GTP酶激活蛋白SH3功能区结合蛋白2(GTPase activating protein SH3 binding protein 2,G3BP2)的表达,进而影响乳腺癌细胞的侵袭。方法应用实时荧光定量PCR(qRT-PCR)检测正常乳腺上皮及乳腺癌细胞系中miR-130a的表达水平;蛋白质印迹法(Western blot)检测改变miR-130a表达水平对乳腺癌细胞株MCF-7和MDA-MB-231中G3BP2及上皮间质转化(epithelial-to-mesenchymal transition,EMT)相关蛋白的影响;双荧光素酶报告基因实验检测miR-130a是否能与G3BP2靶向结合,以及Transwell侵袭实验检测miR-130a表达水平与MCF-7和MDA-MB-231细胞侵袭能力的关系。结果qRT-PCR显示miR-130a表达量在高侵袭乳腺癌细胞株明显高于低侵袭乳腺癌细胞株MCF-7及正常乳腺上皮细胞;Western blot检测显示,miR-130a负向调控G3BP2的表达并促进乳腺癌细胞发生EMT;qRT-PCR显示改变乳腺癌细胞内miR-130a表达后G3BP2 mRNA基本没有变化;双荧光素酶报告基因结果显示,miR-130a能与G3BP2 mRNA的3’UTR结合;Transwell侵袭实验显示,miR-130a促进乳腺癌细胞的体外侵袭。结论miR-130a通过靶向结合G3BP2 mRNA的3’UTR区,在翻译水平抑制G3BP2表达后促进乳腺癌细胞发生EMT,从而促进乳腺癌细胞的侵袭。展开更多
基金supported by the National Natural Science Foundation of China under Grant No. 61101107the Scientific Research and Innovation Plan for the Youth of BUP Tunder Grant No. 2011RC0305the State Major Science and Technology Special Projects under Grant No.2012ZX03004001
文摘Due to the problem of spectrum underutilization and energy inefficiency in wireless communications,the research on energy efficient Cognitive Radio Networks (CRNs) has received significant attention in both industry and academia.In this paper,we consider the problem of optimal spectrum selection and transmission parameters design with the objective of minimizing energy consumption in CRNs.Since the system state cannot be directly observed due to miss detections and estimation errors,we formulate the optimal spectrum access problem as a Partially Observable Markov Decision Process (POMDP).In particular,the proposed scheme selects the optimal spectrum,modulation and coding scheme,transmission power,and link layer frame size in each time slot according to the belief state,which captures all the history information of past actions and observations.The optimal policy can be acquired by solving POMDP problem with linear programming based algorithm.Simulation results show that significant energy savings can be achieved by the proposed scheme.
