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TECHNICAL UPDATE ON
THE PILOT DEVELOPMENT
FOR SECURE SOCIETIES
BDE Hang-out “Updates on Big Data in Secure societies”21/04...
Pilot Architecture
23-mai-16www.big-data-europe.eu
1st Workflow: Image Aggregator
 Rest service called by GUI & Event Detection
 Input:
o Bounding box of the area of inter...
1st Workflow: HDFS
 Input:
o Two satellite images in zip format, each occupying
few GBs.
 Output:
o Distribute parts of ...
1st Workflow: Change Detector
 Parallelizes the change detection algorithm
using Spark.
 Input:
o Two satellite images d...
Change Detector Algorithm
 Two steps:
o Preprocessing to co-register the images
 4 operators
o Main algorithm to perform...
Common workflow: GeoTriples
 Converts geospatial data into RDF.
 Input Scenario I:
o Areas of change from Change Detecto...
Common workflow: Strabon
 Scalable & efficient spatiotemporal RDF store.
 Input:
o Data coming from GeoTriples
o Queries...
Common Workflow: SemaGrow
 Federates Cassandra and Strabon.
 Input:
o Queries from GUI about events or locations with
ch...
Common Workflow: Sextant - A
 Web application running on the client-side.
 Input for Change Detection:
o Area selected b...
Common Workflow: Sextant - B
 Input for Event Detection:
o Keyword (optional)
o Location name or coordinates
o Time
 Out...
Thank you!
Questions?
Links
 Strabon: http://strabon.di.uoa.gr
 GeoTriples: https://github.com/LinkedEOData/GeoTriples
...
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SC7 Hangout 2: Technical update on the pilot development for secure societies

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21/04/2016 George Papadakis Presentation "Technical update on the pilot development for secure societies"

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SC7 Hangout 2: Technical update on the pilot development for secure societies

  1. 1. TECHNICAL UPDATE ON THE PILOT DEVELOPMENT FOR SECURE SOCIETIES BDE Hang-out “Updates on Big Data in Secure societies”21/04/2016 George Papadakis, University of Athens Postdoctoral Researcher
  2. 2. Pilot Architecture 23-mai-16www.big-data-europe.eu
  3. 3. 1st Workflow: Image Aggregator  Rest service called by GUI & Event Detection  Input: o Bounding box of the area of interest (WKT) o The time of interest o A past time, before an event of interest took place  Output: o a set of satellite images downloaded from ESA’s Sentinels Scientific Data Hub. 23-mai-16www.big-data-europe.eu
  4. 4. 1st Workflow: HDFS  Input: o Two satellite images in zip format, each occupying few GBs.  Output: o Distribute parts of every image to the available cluster nodes to facilitate their efficient processing. 23-mai-16www.big-data-europe.eu
  5. 5. 1st Workflow: Change Detector  Parallelizes the change detection algorithm using Spark.  Input: o Two satellite images depicting the same geolocation.  Output: o A set of bounding boxes for the areas with differences between the two snapshots. 23-mai-16www.big-data-europe.eu
  6. 6. Change Detector Algorithm  Two steps: o Preprocessing to co-register the images  4 operators o Main algorithm to perform the actual comparison  Two parallelization strategies: o Image-centric approach o Tile-centric approach 23-mai-16www.big-data-europe.eu
  7. 7. Common workflow: GeoTriples  Converts geospatial data into RDF.  Input Scenario I: o Areas of change from Change Detector  Input Scenario II: o Event summaries from Event Detector  Output: o RDF statements 23-mai-16www.big-data-europe.eu
  8. 8. Common workflow: Strabon  Scalable & efficient spatiotemporal RDF store.  Input: o Data coming from GeoTriples o Queries of the following types:  Get N latest event summaries from location X.  Get event summaries with keyword Y.  Get areas with change in location X.  Output: o Answers to the received queries. 23-mai-16www.big-data-europe.eu
  9. 9. Common Workflow: SemaGrow  Federates Cassandra and Strabon.  Input: o Queries from GUI about events or locations with changes.  Output: o Answers to the received queries. 23-mai-16www.big-data-europe.eu
  10. 10. Common Workflow: Sextant - A  Web application running on the client-side.  Input for Change Detection: o Area selected by user through the interactive map or Location name typed by user o Time interval (optional)  Output: o Calls Image Aggregator o Progress bar 23-mai-16www.big-data-europe.eu
  11. 11. Common Workflow: Sextant - B  Input for Event Detection: o Keyword (optional) o Location name or coordinates o Time  Output: o Latest relevant event summaries. By clicking the title of an event, the user is redirected to a page with the full event description. 23-mai-16www.big-data-europe.eu
  12. 12. Thank you! Questions? Links  Strabon: http://strabon.di.uoa.gr  GeoTriples: https://github.com/LinkedEOData/GeoTriples  Sextant: http://sextant.di.uoa.gr 23-mai-16www.big-data-europe.eu

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