public ArrayList<Long> getSystemDownTime() throws IOException {
		CSVParser csv = new CSVParser(file);
		ArrayList<Long> data = new ArrayList<>();
		long prev_date = Long.MAX_VALUE;
		for (String[] line : csv) {
			long curr_date = SensorMsg.dateToTimeStamp(line[0]);
			if ((curr_date - prev_date) > 900000) {
				data.add(prev_date);
				data.add(curr_date);
			}
			prev_date = curr_date;
		}
		csv.close();
		return data;
	}