The seamless-L0 （SELO） penalty is a smooth function on [0, ∞） that very closely resembles the L0 penalty, which has been demonstrated theoretically and practically to be effective in nonconvex penalization for var...The seamless-L0 （SELO） penalty is a smooth function on [0, ∞） that very closely resembles the L0 penalty, which has been demonstrated theoretically and practically to be effective in nonconvex penalization for variable selection. In this paper, we first generalize SELO to a class of penalties retaining good features of SELO, and then propose variable selection and estimation in linear models using the proposed generalized SELO （GSELO） penalized least squares （PLS） approach. We show that the GSELO-PLS procedure possesses the oracle property and consistently selects the true model under some regularity conditions in the presence of a diverging number of variables. The entire path of GSELO-PLS estimates can be efficiently computed through a smoothing quasi-Newton （SQN） method. A modified BIC coupled with a continuation strategy is developed to select the optimal tuning parameter. Simulation studies and analysis of a clinical data are carried out to evaluate the finite sample performance of the proposed method. In addition, numerical experiments involving simulation studies and analysis of a microarray data are also conducted for GSELO-PLS in the high-dimensional settings.展开更多
Canine coronavirus(CCoV),a member of the genus Alphocoronavirus,is an enveloped,single-stranded positive-sense RNA virus that responsible for gastroenteritis in dogs.In this study,two CCoV isolates were successfully p...Canine coronavirus(CCoV),a member of the genus Alphocoronavirus,is an enveloped,single-stranded positive-sense RNA virus that responsible for gastroenteritis in dogs.In this study,two CCoV isolates were successfully propagated from 53 CCoV-positive clinical specimens by serial passaging in A-72 cells.These two strains,CCoV JS1706 and CCoV JS1712,caused cytopathic effects in A-72 cells.The sizes of virus plaque formed by them differed in early passages.Electron microscopy revealed a large quantity of typical coronavirus particles with 80-120 nm in diameter in cell culture media and cytoplasm of infected cells,in which they appeared as inclusion bodies.RT-PCR analysis of 5 gene indicated that these two isolates were belonged to CCoV lla subtype.Homology of RdRp,S,M and N proteins between the two strains were 100,99.6,99.2 and 100.0%,respectively,whereas they were 99.4-100%,83.1-95.2%,88.5-99.2% and 91.9-99.7%identity compared to CCoV II reference strains.Phylogenetic analysis of RdRp,S,M and N protein showed that they were closely related to CCoV II strains.These two subtype lla isolates will be useful for evaluating the pathogenesis and evolution of CCoV and for developing diagnostic reagents and vaccines.展开更多
Recently, hosts of Medium Access Control （MAC） protocols for Ad hoc radio networks have been proposed to solve the hidden terminal problem and exposed terminal problem. However most of them take into no account the ...Recently, hosts of Medium Access Control （MAC） protocols for Ad hoc radio networks have been proposed to solve the hidden terminal problem and exposed terminal problem. However most of them take into no account the interactions between physical （PHY） system and MAC protocol. Therefore, the current MAC protocols are either inefficient in the networks with mobile nodes and fading channel or difficult in hardware implementation. In this paper, we present a novel media access control for Ad hoc networks that integrates a media access control protocol termed as Dual Busy Tone Multiple Access （DBTMA） into Orthagonal Frequency Division Multiplexing （ OFDM ） system proposed in IEEE 802.11 a standard. The analysis presented in the paper indicates that the proposed MAC scheme achieves performance improvement over IEEE 802.11 protocol about 25% -80% especially in the environment with high mobility and deep fading. The complexity of the proposed scheme is also lower than other implementation of similar busy tone solution. Furthermore, it is compatible with IEEE 802. 11a networks.展开更多
基金Supported by the National Natural Science Foundation of China(11501578,11501579,11701571,41572315)the Fundamental Research Funds for the Central Universities(CUGW150809)
文摘The seamless-L0 （SELO） penalty is a smooth function on [0, ∞） that very closely resembles the L0 penalty, which has been demonstrated theoretically and practically to be effective in nonconvex penalization for variable selection. In this paper, we first generalize SELO to a class of penalties retaining good features of SELO, and then propose variable selection and estimation in linear models using the proposed generalized SELO （GSELO） penalized least squares （PLS） approach. We show that the GSELO-PLS procedure possesses the oracle property and consistently selects the true model under some regularity conditions in the presence of a diverging number of variables. The entire path of GSELO-PLS estimates can be efficiently computed through a smoothing quasi-Newton （SQN） method. A modified BIC coupled with a continuation strategy is developed to select the optimal tuning parameter. Simulation studies and analysis of a clinical data are carried out to evaluate the finite sample performance of the proposed method. In addition, numerical experiments involving simulation studies and analysis of a microarray data are also conducted for GSELO-PLS in the high-dimensional settings.
基金This work was supported by the Open Project Program of Jiangsu Key Laboratory of Zoonosis(No.1604,No.1804)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Canine coronavirus(CCoV),a member of the genus Alphocoronavirus,is an enveloped,single-stranded positive-sense RNA virus that responsible for gastroenteritis in dogs.In this study,two CCoV isolates were successfully propagated from 53 CCoV-positive clinical specimens by serial passaging in A-72 cells.These two strains,CCoV JS1706 and CCoV JS1712,caused cytopathic effects in A-72 cells.The sizes of virus plaque formed by them differed in early passages.Electron microscopy revealed a large quantity of typical coronavirus particles with 80-120 nm in diameter in cell culture media and cytoplasm of infected cells,in which they appeared as inclusion bodies.RT-PCR analysis of 5 gene indicated that these two isolates were belonged to CCoV lla subtype.Homology of RdRp,S,M and N proteins between the two strains were 100,99.6,99.2 and 100.0%,respectively,whereas they were 99.4-100%,83.1-95.2%,88.5-99.2% and 91.9-99.7%identity compared to CCoV II reference strains.Phylogenetic analysis of RdRp,S,M and N protein showed that they were closely related to CCoV II strains.These two subtype lla isolates will be useful for evaluating the pathogenesis and evolution of CCoV and for developing diagnostic reagents and vaccines.
基金This workis supported by National Natural Science Foundation of China (90104018 and 60172052) ,and National"863"High Technology Project(2003AA12331004) .
文摘Recently, hosts of Medium Access Control （MAC） protocols for Ad hoc radio networks have been proposed to solve the hidden terminal problem and exposed terminal problem. However most of them take into no account the interactions between physical （PHY） system and MAC protocol. Therefore, the current MAC protocols are either inefficient in the networks with mobile nodes and fading channel or difficult in hardware implementation. In this paper, we present a novel media access control for Ad hoc networks that integrates a media access control protocol termed as Dual Busy Tone Multiple Access （DBTMA） into Orthagonal Frequency Division Multiplexing （ OFDM ） system proposed in IEEE 802.11 a standard. The analysis presented in the paper indicates that the proposed MAC scheme achieves performance improvement over IEEE 802.11 protocol about 25% -80% especially in the environment with high mobility and deep fading. The complexity of the proposed scheme is also lower than other implementation of similar busy tone solution. Furthermore, it is compatible with IEEE 802. 11a networks.
