Abstract: A train positioning method based on a dynamic map includes: performing train positioning initialization based on a positioning source, and obtaining key point information for creating the dynamic map; generating key point coordinates according to the key point information, and creating the dynamic map; updating a train position on the dynamic map according to train displacement and beacon information; updating the dynamic map, and updating the train position based on the updated dynamic map; and, converting an updated train position in the updated dynamic map into a standard track map, to achieve train positioning. A plurality of initialized positioning sources are used to obtain initialization positioning information of train key points, and creation of a dynamic map is completed.

Abstract: Biologically active variants of epidermal growth factor are provided, comprising tandemly linked units of monomeric EGF. The variants are useful per se as therapeutic agents to promote wound healing. Production of the multimeric EGF by genetically engineered microbial hosts is also described.