3D traveltime calculation is widely used in seismic exploration technologies such as seismic migration and tomography. The fast marching method （FMM） is useful for calculating 3D traveltime and has proven to be effi...3D traveltime calculation is widely used in seismic exploration technologies such as seismic migration and tomography. The fast marching method （FMM） is useful for calculating 3D traveltime and has proven to be efficient and stable. However, it has low calculation accuracy near the source, which thus gives it low overall accuracy. This paper proposes a joint traveltime calculation method to solve this problem. The method firstly employs the wavefront construction method （WFC）, which has a higher calculation accuracy than FMM in calculating traveltime in the small area near the source, and secondly adopts FMM to calculate traveltime for the remaining grid nodes. Due to the increase in calculation precision of grid nodes near the source, this new algorithm is shown to have good calculation precision while maintaining the high calculation efficiency of FMM, which is employed in most of the computational area. Results are verified using various numerical models.展开更多
To estimate the spreading sequence of the direct sequence spread spectrum (DSSS) signal, a fast algorithm based on maximum likelihood function is proposed, and the theoretical derivation of the algorithm is provided. ...To estimate the spreading sequence of the direct sequence spread spectrum (DSSS) signal, a fast algorithm based on maximum likelihood function is proposed, and the theoretical derivation of the algorithm is provided. By simplifying the objective function of maximum likelihood estimation, the algorithm can realize sequence synchronization and sequence estimation via adaptive iteration and sliding window. Since it avoids the correlation matrix computation, the algorithm significantly reduces the storage requirement and the computation complexity. Simulations show that it is a fast convergent algorithm, and can perform well in low signal to noise ratio (SNR).展开更多
Objective:To evaluate the value of enhanced luminescence enzyme immunoassay in the diagnosis of Neisseria gonorrhea(NG) infection. Methods: Anti-catalase antibody for Neisseria gonorrheae combined with enhanced lumine...Objective:To evaluate the value of enhanced luminescence enzyme immunoassay in the diagnosis of Neisseria gonorrhea(NG) infection. Methods: Anti-catalase antibody for Neisseria gonorrheae combined with enhanced luminescence enzyme immunoassay were used to test for N. gonorrhea. Results: A minimum of 1×10^4/CFU of GC in genital tract secretions or urine could be detected with the technique of luminescence enzyme immunoassay. Conclusion : The enhanced luminescence enzyme immunoassay has the advantage of high sensitivity and specificity for diagnosing NG from genitourinary tract secretion and urine.展开更多
基金supported by NSFC(Nos.41274120,41404085,and 41504084)
文摘3D traveltime calculation is widely used in seismic exploration technologies such as seismic migration and tomography. The fast marching method （FMM） is useful for calculating 3D traveltime and has proven to be efficient and stable. However, it has low calculation accuracy near the source, which thus gives it low overall accuracy. This paper proposes a joint traveltime calculation method to solve this problem. The method firstly employs the wavefront construction method （WFC）, which has a higher calculation accuracy than FMM in calculating traveltime in the small area near the source, and secondly adopts FMM to calculate traveltime for the remaining grid nodes. Due to the increase in calculation precision of grid nodes near the source, this new algorithm is shown to have good calculation precision while maintaining the high calculation efficiency of FMM, which is employed in most of the computational area. Results are verified using various numerical models.
基金supported by Joint Foundation of and China Academy of Engineering Physical (10676006)
文摘To estimate the spreading sequence of the direct sequence spread spectrum (DSSS) signal, a fast algorithm based on maximum likelihood function is proposed, and the theoretical derivation of the algorithm is provided. By simplifying the objective function of maximum likelihood estimation, the algorithm can realize sequence synchronization and sequence estimation via adaptive iteration and sliding window. Since it avoids the correlation matrix computation, the algorithm significantly reduces the storage requirement and the computation complexity. Simulations show that it is a fast convergent algorithm, and can perform well in low signal to noise ratio (SNR).
文摘Objective:To evaluate the value of enhanced luminescence enzyme immunoassay in the diagnosis of Neisseria gonorrhea(NG) infection. Methods: Anti-catalase antibody for Neisseria gonorrheae combined with enhanced luminescence enzyme immunoassay were used to test for N. gonorrhea. Results: A minimum of 1×10^4/CFU of GC in genital tract secretions or urine could be detected with the technique of luminescence enzyme immunoassay. Conclusion : The enhanced luminescence enzyme immunoassay has the advantage of high sensitivity and specificity for diagnosing NG from genitourinary tract secretion and urine.
