Abstract: A digital data processing method obtains an authorization level of a connected client device. The method further searches for available digital data to be browsed corresponding to the obtained authorization level and transmits parameters of the available digital data to the connected client device. The method further determines whether the connected client device has authorization to process specified digital data selected from the available digital data when a processing command is received. If the connected client device has authorization to process the specified digital data, the method transmits the specified digital data to the connected client device.

Abstract: A roll-call processing method is executed by a server. The method records first connection information of a first electronic device and transmits a roll-call interface to the first electronic device when the server receives a request for the roll-call interface from the first electronic device. The method further records second connection information of at least one second electronic device and receives a photo transmitted from the second electronic device. The method transmits the received photo of the second electronic device to the first electronic device to display the received photo on the roll-call interface of the first electronic device.

Abstract: An inner scattering billboard includes a light directing body, an advertising membrane and a light source. The light directing body contains a plurality of light directing particles inside to diffuse and direct light. Thus light rays emitted from the light source into the light directing body are scattered to allow the light directing body to become a planar light source of even luminosity. The advertising membrane has an advertising symbol located on the surface to be evenly illuminated. The billboard can be made thinner. An LED may be adopted as the light source to save electric power and reduce user's operation cost.