1. Date: 23/09/2010 FIS 2010 DoctoralConsortium Enabling Semantic Integration of Streaming Data Sources Jean-Paul Calbimonte Ontology Engineering Group. Departamento de Inteligencia Artificial. Facultad de Informática, Universidad Politécnica de Madrid. Campus de Montegancedo s/n. 28660 Boadilla del Monte. Madrid. Spain {jpcalbimonte}@fi.upm.es Supervisor: Oscar Corcho DC Scientific advisor: AchimRettinger

2. Index Introduction Problem statement Main research questions Approach Proposed solution Work done so far Evaluation Future work 2 EnablingSemanticIntegration of Streaming Data Sources

4. Continuously appended data

5. Potentially infinite

6. Time-stamped tuples

7. Continuous queries

8. Latest used in queries

10. Cheap, Noisy, Unreliable (depends)

11. Low computational, power resources, storage

12. Distributed query execution

13. Routing, OptimizationQuery EnablingSemanticIntegration of Streaming Data Sources

15. Distributed sources

16. Semantic heterogeneity

17. Semantic data provision only for stored data

18. Need for live streaming continuous queriesSensor Network Database Data Integrate Decl. Query Integrated view Stream Data 4 SemanticIntegrationStreaming Data Sources

20. Expose streaming data for the semantic web

21. Integrate streaming sources through ontology mappings

22. Optimize distributed query execution for streaming + stored dataOntology-based Data Access Heterogeneous data Integration Streaming Data Access Distributed Query Processing RDF Streams Querying Semantic Integrator q 5 EnablingSemanticIntegration of Streaming Data Sources

24. Identify limitations

25. Potential gaps

26. Incremental solution proposals

27. Ontology-based data access to streams

28. Semantic streaming query language

29. Semantic integration for distributed streams

30. Stream query optimization

31. Evaluation

32. SemSorGrid4Env project

33. Benchmarks, LinearRoadEnablingSemanticIntegration of Streaming Data Sources

34. 7 Proposed Solution Client SPARQLSTR (Og) Query reconciliation Ontology-to-Ontologymappings SPARQLSTR (O1 O2On) Query translation Ontology-to-Sourcemappings Sensor Network (S1) SPARQLSTR algebra(S1 S2 Sm) Relational DB (S2) Rewriter Query Evaluator Optimizer Rewriter Stream Engine (S3) Distributed Query Processing RDF Store (Sm) Ontology-based Streaming Data Access Service 7 SemanticIntegrationStreaming Data Sources

36. Define SPARQLSTRlanguagesyntax and semantics

37. Enableengine support for « S2O » documents, SPARQLSTR queries

38. Enabledengine support for SNEEql translation and connection

39. Limited to non-distributed scenario initially8 SemanticIntegrationStreaming Data Sources

40. v v So Far... 9 Enabling Semantic Integration of Streaming Data Sources envdata_westbay Feature envdata_chesil locatedInRegion v envdata_milford Observation hasObservationResult S2O Mapping v envdata_hornsea Streams Ontologies observedProperty envdata_rhylflats Region xsd:float Timestamp: long Hs : float Lon: float Lat: float WaveHeightProperty PREFIX cd: <http://www.semsorgrid4env.eu/ontologies/CoastalDefences.owl#> PREFIX sb: <http://www.w3.org/2009/SSN-XG/Ontologies/SensorBasis.owl#> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> SELECT ?waveheight ?wavets ?lat ?lon FROM STREAM <http://www.semsorgrid4env/ccometeo.srdf> WHERE { ?WaveObs a cd:Observation; cd:observationResult ?waveheight; cd:observationResultTime ?wavets; cd:observationResultLatitude ?lat; cd:observationResultLongitude ?lon; cd:observedProperty ?waveProperty; cd:featureOfInterest ?waveFeature. ?waveFeature a cd:Feature; cd:locatedInRegioncd:SouthEastEnglandCCO. ?waveProperty a cd:WaveHeight. } (SELECT Lon,timestamp,Hs,Lat FROM envdata_rhylflats) UNION (SELECT Lon,timestamp,Hs,Lat FROM envdata_hornsea) UNION (SELECT Lon,timestamp,Hs,Lat FROM envdata_milford) UNION (SELECT Lon,timestamp,Hs,Lat FROM envdata_chesil) UNION (SELECT Lon,timestamp,Hs,Lat FROM envdata_perranporth) UNION (SELECT Lon,timestamp,Hs,Lat FROM envdata_westbay) UNION (SELECT Lon,timestamp,Hs,Lat FROM envdata_pevenseybay) SNEEql SPARQLSTR

42. SPARQL construct expressions, aggregates, projected operators

43. Implement adapters for other streaming sources

44. Add query rewriting algorithms

45. Ontology-based streaming data integration

46. Horizontal & vertical integration

47. Integrate streaming + stored data

48. RDF data sources integration

49. Streaming query optimization

50. Analyze cost models

51. Streaming sources statistics and metadata

52. Quantitative evaluation10 SemanticIntegrationStreaming Data Sources

53. Thanks! 11 Enabling Semantic Integration of Streaming Data Sources Enabling Semantic Integration of Streaming Data Sources

55. Sahoo, S.S., Halb, W., Hellmann, S., Idehen, K., Jr, T.T., Auer, S., Sequeda, J., Ezzat, A.: A survey of current approaches for mapping of relational databases to RDF. W3C (January 2009)

56. Arasu, A., Babu, S., Widom, J.: The cql continuous query language: semantic foundations and query execution. The VLDB Journal 15(2) (June 2006) 121-142

57. Brenninkmeijer, C.Y., Galpin, I., Fernandes, A.A., Paton, N.W.: A semantics for a query language over sensors, streams and relations. In: BNCOD '08. (2008) 87-99

58. Barrasa, J., Oscar Corcho, Gomez-Perez, A.: R2O, an extensible and semantically based database-to-ontology mapping language. In: SWDB2004. (2004) 1069-1070

59. Lenzerini, M.: Data integration: a theoretical perspective. In: PODS '02. (2002) 233-246

60. Barrasa Rodriguez, J., Gomez-Perez, A.: Upgrading relational legacy data to the semantic web. In: WWW '06. (2006) 1069-1070

61. Barbieri, D.F., Braga, D., Ceri, S., Della Valle, E., Grossniklaus, M.: C-sparql: A continuous query language for rdf data streams (to appear). In: (IJSC). (2010)

62. Bolles, A., Grawunder, M., Jacobi, J.: Streaming SPARQL - extending SPARQL to process data streams. In: ESWC 08. (2008) 448-462

63. Kossmann, D.: The state of the art in distributed query processing. ACM Comput. Surv. 32(4) (2000) 422-469

64. Perez, J., Arenas, M., Gutierrez, C.: Semantics and complexity of sparql. ACM Trans. Database Syst. 34(3) (2009) 1-45

65. Calvanese, D., De Giacomo, G., Lembo, D., Lenzerini, M., Rosati, R.: DL-Lite: Tractable description logics for ontologies. In: AAAI 2005. (2005) 602-607

66. Poggi, A., Lembo, D., Calvanese, D., Giacomo, G.D., Lenzerini, M., Rosati, R.: Linking data to ontologies. J. Data Semantics 10 (2008) 133-173

68. Ontology-based data access & integration SquirrelRDF RDBToOnto Relational.OWL SPASQL Virtuoso D2RQ MASTRO R2O + ODEMapster ODEMapster MySQL Oracle ...others ODEMQL Transform relational query Ontological query Ontological model Database OWL Mapping R2O OBSERVER SIMS Carnot DWQ PICSEL MOMIS Ontological query Ontological model Transform relational query Databases Mappings 14 SemanticIntegrationStreaming Data Sources

69. 15 Background: Approaches & Technologies DSMS DQP QP S-RDF Ontology-based Data Access Heterogeneous data Integration Streaming Data Access Distributed Query Processing RDF Streams Querying R2O + ODEMapster C-SPARQL extensions SNEE/SNEEql Semantic Integrator q 15 SemanticIntegrationStreaming Data Sources

71. speed

72. direction

75. Mappingexpression overstreamingsources conjunctive query

77. PREFIX rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns#

78. SELECT ?speed ?name

79. FROM STREAM <http://www.ssg4env.eu/Readings.srdf>

80. [RANGE 10 MINUTE STEP 1 MINUTE]

81. WHERE {

82. ?WindSpeed a fire:WindSpeedMeasurement;

83. fire:hasSpeed ?speed;

84. fire:isProducedBy ?sensor;

85. fire:hasTimestamp ?time.

86. ?sensor a fire:Sensor;

87. fire:hasName ?name.

88. }Work in progress: removing redundant queries, basic optimisations, more complex scenarios 18 SemanticIntegrationStreaming Data Sources

89. 19 SemanticIntegrationInteractions Semantic Integrator Streaming Data Resource Stored Data Resource Consumer IntegrateAs (StrRes,StoRes,map) IntegratedRes SPARQLExecuteFactory(IntegratedRes, query) SNEEqlExecuteFactory(StreamingRes, querySNEEql) accessStreamingRes GetResponseItem(accessStreamingRes) repeat results SQLExecuteFactory(StoredRes, querySQL) results accessIntegratedRes GetResponseItem(accessIntegratedRes) 19 SemanticIntegrationStreaming Data Sources