Presentation by Jose M. Barone Mattos Computer Engineer, Municipality of Montevideo FIWARE Tech Summit 28-29 November, 2017 Malaga, Spain

1. Estimated Time Arrival Implementation
Working with Fiware in Montevideo
Intendencia de Montevideo (IM), Uruguay
Depto. Desarrollo Sostenible e Inteligente
Jose Miguel Barone
jose.m.barone@imm.gub.uy

2. Montevideo?
1

3. Public transport
▪ ~1500 buses in 4 companies
▪ typical network with routes, bus stops, terminals, …

4. Public transport ...
Bus Company
cellular network
Intendencia
de
Montevideo
VPN network
(UDP/IP)

5. Streaming ingestion (Flume / Cygnus)
Listener
OS service
data reception
(multithreaded)
Parsing
thread
Parsing
thread
Avro Flume
Source
Avro Flume
Source
send events
to flume
(round robin)

6. Event processing
Positions flume channel
ETA flume channel
Avro Flume
Source
Custom
positions
flume sink
Custom ETA
flume sink

7. Positions Sink
▪ Records positions as fast as possible
▪ Redis cluster in memory (key/value NoSQL)
Redis
Master Node
Write only
Redis
Slave Node
Redis
Slave Node
(synchronization)
Read only
slaves

8. ETA Sink
▪ “Persist” ETA data in Redis cluster like Positions Sink
▪ Process calculations
Bus
Stop
interval T

9. Bus at Bus Stop?
▪ So ...
• Project real GPS to route
• Obtain distance to beginning of the route
• Find the right interval using distance comparison
▪ We have precalculated at load time
• Route and Bus Stops geometry
• Distance from every Bus Stop to beginning of the route
▪ Configuration parameter: distance to Bus Stop

10. Time in interval
▪ But ...
• Time at the interval will be the average with existent
value
• Smooth “anormal” values
▪ Bus it’s at Bus Stop N
• if we find it at Bus Stop N-1
• Time difference => time at the interval
▪ Configuration parameter: max difference time considered

11. The city alive
▪ The time per interval will be continuously adjusted

12. Howto get the ETA?
▪ Search the bus “backward” from the Bus Stop
▪ Accumulate the times per interval
▪ When we find it => return position and time
▪ Parameters
• Bus Stop
• Bus Line(s)
▪ Optimization: matrix with the accumulated to every pair (i,j) on a route
▪ At any change, recalculate to the end of the route

13. 12

14. 13
Many other Fiware applications...
● Garbage trucks GPS
● Sensors
○ Air quality
○ Radiometer
○ Sanitation
○ Sea level
○ Pluviometers
○ ...

15. Thank you!
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