Road Traffic Monitoring System Based on Mobile Devices and Bluetooth Low Energy Beacons

Algorithm 3

Aggregation function.

1Input: Records, window_size

2Output: Aggregates

3create table Aggregates

4with columns time, min_1_1, max_1_1,..., min_m_n, max_m_n

5Times:= Select time from Records

6for each t in Times do

7begin

8for refPos:= 1..m do

9for bID:= 1..n do

10begin

11RSSI_data:= Select RSSI from Records

12where time is between t - window_size and t

13and distance(position, refPos) <= d_max

14and beacon_ID = bID

15min_refPos_bID:= min(RSSI_data)

16max_refPos_bID:= max(RSSI_data)

17end

18Insert t, min_1_1, max_1_1,..., min_m_n, max_m_n into Aggregates

19End