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Facilitated by the establishment of terrestrial networks and satellite constellations of Automatic Identification System (AIS) receivers, large quantities of spatial and temporal information that trace ships' paths have been collected. The exponential increase in the amount of AIS data has caused expensive and time-consuming transmission, calculation and storage problems. Using appropriate trajectory simplification methods in a timely manner to compress redundant information while minimising the loss of importation information is important. To minimise the simplification error, this paper proposes an online multi-dimensional simplification algorithm for AIS trajectory streaming data. The simplification algorithm takes into account position, direction and speed preservation. Finally, a comparison experiment with other algorithms is made to examine the effectiveness of this algorithm. The results indicate that the proposed online multi-dimensional simplification algorithm can effectively preserve a ship's motion state, including its position, speed and course. [ABSTRACT FROM AUTHOR]

Facilitated by recent establishment of terrestrial networks and satellite constellations of Automatic Identification System (AIS) receivers, ship trajectories are becoming increasingly available and the size of recorded trajectories is getting larger. Large sets of trajectories create problems of storing, transmitting and processing data. Using appropriate methods, an accurate representation of the original trajectories can be obtained by compressing redundant information, while maintaining the main characteristic elements. In this paper, a new scheme and the implementation of the Douglas-Peucker (DP) algorithm are presented, which can simplify AIS trajectories by extracting characteristic points. As for the simplification threshold, the solo parameter of the DP algorithm, a new AIS-based minimum ship domain evaluation method is proposed and acts as criteria for simplification threshold determination. Finally, a validation is made to examine the effectiveness of the DP simplification algorithm and the rationality of the simplification threshold. The result indicates that the DP algorithm can simplify AIS trajectories effectively; the simplification threshold is scientific and reasonable. [ABSTRACT FROM AUTHOR]

Objective: To detect bcl-2 gene expression in Epstein-Barr virus (EBV)-infected human gastric epithelial cell line GES-1 for understanding the role of bcl-2 gene in the carcinogenesis of EBV-associated gastric carcinoma., Methods: Akata 1061 cells producing recombined EBV carrying neomycin resistance gene (NEOr) was used to mediate the EBV infection of human gastric epithelial cell line GES-1 via close contact, with the empty plasmid pcDNA3-transfected GES-1 cells via lipofectamine method as a control. The EBV-infected and pcDNA3-transfected cells were cloned by limited dilution and the positive clones selected with G418. Immunocytochemical staining was performed to detect the expressions of EBNA1 and Bcl-2 protein., Results: Bcl-2 protein expression was detected in EBV-infected cells but not in the control cells., Conclusion: EBV infection can increase Bcl-2 expression in gastric epithelial cells, and such cell transformation effect of EBV is related to the overexpression of bcl-2 gene.