A soft decision value correction method can detect interference occurring in a desired wave and correct a soft decision value where a received power difference between the desired wave and an interference wave is small. The IDAC comprises a first active device that generates a reference current, and a device that forms a first source degeneration resistance for the first active device. It is suitable to form the film while maintaining the temperature of the substrate at 400\xb0 C. According to another aspect of the invention, the members of the social network may include actual members and virtual members.