Abstract: A file transfer method adaptive to a server is disclosed. The file transfer method includes following steps: dividing the file into a plurality of fragments; sending a piece of validation data of the file to at least one client based on TCP; multicasting the plurality of fragments to the at least one client based on UDP; determining whether a command from the at least one client questing for reissuing to send a lost part of the plurality of fragments is received; sending the lost part of the plurality of fragments to the corresponding client based on TCP when the command is received.

Abstract: A file transfer method adaptive to a server is disclosed. The file transfer method includes following steps: dividing the file into a plurality of fragments; sending a piece of validation data of the file to at least one client based on TCP; multicasting the plurality of fragments to the at least one client based on UDP; determining whether a command from the at least one client questing for reissuing to send a lost part of the plurality of fragments is received; sending the lost part of the plurality of fragments to the corresponding client based on TCP when the command is received.

Abstract: A mobile device including an antenna structure is provided. The antenna structure includes a main radiation element, a parasitical element, and a tunable element. The main radiation element has a feeding pin coupled to a signal source, wherein the feeding pin is substantially located at an end of the main radiation element. The parasitical element is close to the main radiation element, and has a parasitical pin which is substantially located at an end of the parasitical element. The tunable element includes a switch and a plurality of paths, wherein the switch selectively couples one of the paths to the parasitical pin in such a manner that the antenna structure operates in multiple bands.