$my_score = abs(($semester['time_end'] + $semester['time_start']) / 2 - $time_target);

      if ($best_score == -1 || $my_score < $best_score)

	{

	  $best_semester = $semester;

	  $best_score = $my_score;

	}

    }

  if (!empty($best_semester))

    return $best_semester;

  return $semester;

}