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Question 1 An MP3-Player is specified as follows. • Power switches the device on and off. • When the device is switched on at first, its display shows the play list (see the figure below); however no music is played yet. • One can start and stop playing the music with the play button. When music is played, the display shows detailed information about the played title. • With the menu button, you can switch between the play-list and the title-display. • With forward button, one can wind a title, when the player is paused. • The adjustment can be done with the volume buttons: + and -. There are only three volume levels: quiet, medium and loud. When music starts to play, the volume level is quiet. • When the reset button is pressed, the system goes in the initial state. • Pressing – when the player is quiet doesn’t change the volume. Similarly pressing + in the state loud does not change the volume. Model this device using UML State Machines.

menu play

forward