def utc2jst(utc)
      jst = utc + Const::JST_OFFSET * 60 * 60
      return Time.new(
        jst.year, jst.month, jst.day,
        jst.hour, jst.min, jst.sec + Rational(jst.usec, 10 ** 6),
        sprintf("+%02d:00", Const::JST_OFFSET)
      )
    rescue => e
      raise
    end
def utc2jst(utc)
      jst = utc + Const::JST_OFFSET * 60 * 60
      return Time.new(
        jst.year, jst.month, jst.day,
        jst.hour, jst.min, jst.sec + Rational(jst.usec, 10 ** 6),
        sprintf("+%02d:00", Const::JST_OFFSET)
      )
    rescue => e
      raise
    end
=========================================================================
 UTC(協定世界時) -> JST(日本標準時)

 * JST = UTC + 09:00

 @param:  utc  (Time Object)
 @return: jst  (Time Object)
=========================================================================