为提高遥感影像检索的精度,提出一种基于快速查找密度峰值聚类(Fast Search and Find of Density Peaks,FSFDP)的改进视觉词袋(Bag of Visual word,BoV)模型,该方法充分利用FSFDP聚类算法分类精度高和聚类参数易于选择等优点,增强BoV模...为提高遥感影像检索的精度,提出一种基于快速查找密度峰值聚类(Fast Search and Find of Density Peaks,FSFDP)的改进视觉词袋(Bag of Visual word,BoV)模型,该方法充分利用FSFDP聚类算法分类精度高和聚类参数易于选择等优点,增强BoV模型特征量化的稳定性和可靠性。实验表明,与经典BoV模型相比,FSFDP-BoV模型能够得到更高的检索精度。展开更多
The(un)forced(un)damped parametric pendulum oscillator(PPO)is analyzed analytically and numerically using some simple,effective,and more accurate techniques.In the first technique,the ansatz method is employed for ana...The(un)forced(un)damped parametric pendulum oscillator(PPO)is analyzed analytically and numerically using some simple,effective,and more accurate techniques.In the first technique,the ansatz method is employed for analyzing the unforced damped PPO and for deriving some optimal and accurate analytical approximations in the form of angular Mathieu functions.In the second approach,some approximations to(un)forced damped PPO are obtained in the form of trigonometric functions using the ansatz method.In the third approach,He’s frequency-amplitude principle is applied for deriving some approximations to the(un)damped PPO.In the forth approach,He’s homotopy technique is employed for analyzing the forced(un)damped PPO numerically.In the fifth approach,the p-solution Method,which is constructed based on Krylov–Bogoliúbov Mitropolsky method,is introduced for deriving an approximation to the forced damped PPO.In the final approach,the hybrid Padé-finite difference method is carried out for analyzing the damped PPO numerically.All proposed techniques are compared to the fourth-order Runge–Kutta(RK4)numerical solution.Moreover,the global maximum residual distance error is estimated for checking the accuracy of the obtained approximations.The proposed methodologies and approximations can help many researchers in studying and investigating several nonlinear phenomena related to the oscillations that can arise in various branches of science,e.g.waves and oscillations in plasma physics.展开更多
Primate bocaparvovirus(BOV) is a possible cause of respiratory disorders and gastroenteritis in humans. However, the diversity and evolution of these viruses remain largely unknown, despite the identification of a gro...Primate bocaparvovirus(BOV) is a possible cause of respiratory disorders and gastroenteritis in humans. However, the diversity and evolution of these viruses remain largely unknown, despite the identification of a growing number of BOVs in non-human primates(NHPs). Here, we report the identification of a novel BOV(provisionally named Macaca mulatta bocaparvovirus [MmBOV]) in the feces of wild Macaca mulatta in China by viral metagenomic analysis. Seven of 400 fecal samples from Macaca mulatta were positive for MmBOV. An almost complete genome sequence of 4,831 nucleotides was obtained, which had genomic organization and protein motifs similar to human bocaviruses(HOBVs), and shared characteristically low G/C content and weak codon usage bias. Sequence analyses of NS1, NP1, and VP1 revealed that Mm BOV was most closely related to HBOV4 of Primate bocaparvovirus 2(approximately 68.4%/70.6%, 73.3%/67.6%, and 70.4%/73.1% nucleotide/amino acid identities, respectively). Additionally, phylogenetic analysis revealed that Mm BOV formed an independent peripheral branch, but clustered closely with those of the Primate bocaparvovirus species in the BOV genus(particularly HBOV4). These data strongly suggest that HBOV4 originated from NHP bocaparvoviruses around 200–300 years ago, and that NHPs may act as HBOV reservoirs. Following the International Committee of Taxonomy for Viruses guidelines, we propose Mm BOV as a new species(tentatively named Primate bocaparvovirus 3) in the genus Bocaparvovirus, which is the first report of a novel species of primate BOV. Our data facilitate future research on the genetic diversity and evolution of primate bocaparvoviruses and highlight the importance of bocaparvovirus surveys in wild NHPs.展开更多
文摘为提高遥感影像检索的精度,提出一种基于快速查找密度峰值聚类(Fast Search and Find of Density Peaks,FSFDP)的改进视觉词袋(Bag of Visual word,BoV)模型,该方法充分利用FSFDP聚类算法分类精度高和聚类参数易于选择等优点,增强BoV模型特征量化的稳定性和可靠性。实验表明,与经典BoV模型相比,FSFDP-BoV模型能够得到更高的检索精度。
基金The authors express their gratitude to Princess Nourah bint Abdulrahman University Researchers Supporting Project (Grant No. PNURSP2022R17)Taif University Researchers supporting project number (TURSP2020/275), Taif University, Taif, Saudi Arabia。
文摘The(un)forced(un)damped parametric pendulum oscillator(PPO)is analyzed analytically and numerically using some simple,effective,and more accurate techniques.In the first technique,the ansatz method is employed for analyzing the unforced damped PPO and for deriving some optimal and accurate analytical approximations in the form of angular Mathieu functions.In the second approach,some approximations to(un)forced damped PPO are obtained in the form of trigonometric functions using the ansatz method.In the third approach,He’s frequency-amplitude principle is applied for deriving some approximations to the(un)damped PPO.In the forth approach,He’s homotopy technique is employed for analyzing the forced(un)damped PPO numerically.In the fifth approach,the p-solution Method,which is constructed based on Krylov–Bogoliúbov Mitropolsky method,is introduced for deriving an approximation to the forced damped PPO.In the final approach,the hybrid Padé-finite difference method is carried out for analyzing the damped PPO numerically.All proposed techniques are compared to the fourth-order Runge–Kutta(RK4)numerical solution.Moreover,the global maximum residual distance error is estimated for checking the accuracy of the obtained approximations.The proposed methodologies and approximations can help many researchers in studying and investigating several nonlinear phenomena related to the oscillations that can arise in various branches of science,e.g.waves and oscillations in plasma physics.
基金the National Science and Technology Major Project(2018ZX10301408-001).
文摘Primate bocaparvovirus(BOV) is a possible cause of respiratory disorders and gastroenteritis in humans. However, the diversity and evolution of these viruses remain largely unknown, despite the identification of a growing number of BOVs in non-human primates(NHPs). Here, we report the identification of a novel BOV(provisionally named Macaca mulatta bocaparvovirus [MmBOV]) in the feces of wild Macaca mulatta in China by viral metagenomic analysis. Seven of 400 fecal samples from Macaca mulatta were positive for MmBOV. An almost complete genome sequence of 4,831 nucleotides was obtained, which had genomic organization and protein motifs similar to human bocaviruses(HOBVs), and shared characteristically low G/C content and weak codon usage bias. Sequence analyses of NS1, NP1, and VP1 revealed that Mm BOV was most closely related to HBOV4 of Primate bocaparvovirus 2(approximately 68.4%/70.6%, 73.3%/67.6%, and 70.4%/73.1% nucleotide/amino acid identities, respectively). Additionally, phylogenetic analysis revealed that Mm BOV formed an independent peripheral branch, but clustered closely with those of the Primate bocaparvovirus species in the BOV genus(particularly HBOV4). These data strongly suggest that HBOV4 originated from NHP bocaparvoviruses around 200–300 years ago, and that NHPs may act as HBOV reservoirs. Following the International Committee of Taxonomy for Viruses guidelines, we propose Mm BOV as a new species(tentatively named Primate bocaparvovirus 3) in the genus Bocaparvovirus, which is the first report of a novel species of primate BOV. Our data facilitate future research on the genetic diversity and evolution of primate bocaparvoviruses and highlight the importance of bocaparvovirus surveys in wild NHPs.
