function _makeDtstamp() {
    $this->dtstamp['value'] = array( 'year'  => date( 'Y' )
                                   , 'month' => date( 'm' )
                                   , 'day'   => date( 'd' )
                                   , 'hour'  => date( 'H' )
                                   , 'min'   => date( 'i' )
                                   , 'sec'   => date( 's' ) - date( 'Z' ));
    $this->dtstamp['params'] = null;
  }