Abstract: Disclosed is a method for setting up a substituted ring back tone (RBT) provided from a predetermined communication provider, and more particularly, a method and system for recognizing a first substituted RBT of a first subscriber and setting up the first substituted RBT as a substituted RBT of a second subscriber, between subscribers of different communication providers. According to the present invention, it is possible to easily copy a substituted RBT from another user's substituted RBT and set up the same as a user's own substituted RBT. In this instance, the substituted RBT is provided according to a request for a call setup of a mobile terminal. Also, it is possible to set up a substituted RBT of a subscriber of a different communication provider as a user's substituted RBT, while not receiving predetermined information from the communication provider.

Abstract: An Orthogonal Frequency and Code Hopping Multiplexing (OFCHM) communication method based Orthogonal Frequency Division Multiplexing (OFDM) in a wireless communication system in which a plurality of communication channels are synchronized through a single medium. Six types of spreading and hopping methods are included, a method of controlling spreading and hopping depending on channel states, and a method of determining whether radio resources, consisting of subcarriers and orthogonal codewords, are allocated in a hopping manner according to the quality of service in the OFCHM communication method based OFDM. Furthermore, an embodiment employing six multiple array antennas is included.

Abstract: The present invention generally relates to a structure of liquid crystal cells and projection lenses and an image projection system using the same, and more specifically, to a structure of liquid crystal cells which rotates and is easily movable in a predetermined axial direction and projection lenses for an LCD projector easily movable in a predetermined axial direction and an image projection system using the same. The structure of the liquid crystal cells and the projection lenses in accordance with the present invention and the image projection system using the same can easily control the liquid crystal cells and the projection lenses in order to exactly adjust focuses thereof.

Abstract: A cylinder block for an automotive engine that includes a sintered cylindrical body made of a first metal, the sintered cylindrical body having a plurality of pores. A powder of a second metal is dispersed into the pores of the sintered cylindrical body, and a cylinder block body is disposed around the sintered cylindrical body while filling the pores of the sintered cylindrical body. The main body is made of a third metal and integrally formed with the sintered cylindrical body by an intemetallic compound formed by a reaction between the first, second, and third metals.

Abstract: The present invention relates to a manufacturing method of aluminum alloy having high wear resistance, in particular, to manufacturing method of aluminum alloy by dispersing silicon particle on only required part of wear resistance, and infiltrating the molten metal into the preform of silicon particle.

Abstract: The present invention relates to a manufacturing method of preform for composite material of automobile, in particular, to an economical and easy mass-production manufacturing method of preform including the steps of manufacturing a wet sheet by pouring a suspension prepared by adding inorganic binder, organic binder and cohesion agent to reinforced fiber, into vacuum suction equipment, and forming the sheet into a cylindrical shape with cylindrical press and deforming the sheet form before drying.