A network is represented using a graph. With this configuration, a problem that the internal clock signal is continuously controlled to a wrong direction due to malfunction of aliasing does not occur. When the synthetic speech is output to be superposed on the music during output, the apparatus gradually decreases a tone volume of the music. The spring end coils have larger diameter than the inner coils to reduce the likelihood of the spring end coil end interfering with the cartridge subassembly. The database manager also generates an error detection value for the database after it has been updated with all the operation entries from the journal. , z\u22121} to obtain the basic matrix Hb.