def decode_file_name(aFilename)
      prefix,date,ext = aFilename.scan(/(.*?)\-(.*?)\.(.*)/).flatten
      return Time.from_date_numeric(date)
    end
def decode_file_name(aFilename)
      prefix,date,ext = aFilename.scan(/(.*?)\-(.*?)\.(.*)/).flatten
      return Time.from_date_numeric(date)
    end
return date based on filename