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RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
A Hierarchical approach towards Efficient and Expressive Stream Reasoning
Riccardo Tommasini (Ph.D Student at Politecnico di Milano, DEIB )
Advisor: Emanuele Della Valle (Assistant Professor at Politecnico di Milano, DEIB)
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Web Reasoning and Rule Systems Conf. 2016,
Doctoral Consortium
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Introduction
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RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano) 3
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano) 4
Complex Domains
Incomplete
Vast
NoisyRapidly Changing
Reactive Time Aware
Heterogeneous
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Stream Reasoning
Supports complex domains decision making in real-time (reactively).
I.e., making sense of vast and heterogeneous,
noisy and incomplete streams of data.
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Vision
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Stream Processing and Reasoning
Data Stream Management Systems (DSMS) e.g., Esper, Flink
Complex Event Processing Engines (CEP) e.g., Drools Fusion, Esper.
RDF Stream Processing (RSP) e.g., C-SPARQL, CQELS, SKB.
Rule Based Systems e.g., (RBS) EP-SPARQL, Sparkwave.
Ontology Based Data Access (OBDA) e.g., Morphstream, STARQL.
Incremental Maintenance of Ontology Materialisation (IMOM), e.g, RDFox, TrOWL
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State-of-the-art
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano) 7
SR DSMS CEP RSP RBS OBDA IMOM
Vast x x x
Heterogeneous x x x x x
Noisy x x
Incomplete x x x x
Stream x x x
Time-Aware x x x
Complex Domains x x x
Approaches VS Challenges
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano) 8
Research QuestionCan we realise an expressive and efficient stream reasoning?
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano) 9
Research QuestionCan we realise an expressive and efficient stream reasoning?
Still unanswered!
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano) 10
Research QuestionCan we realise an expressive and efficient stream reasoning,
using a hierarchical approach?
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Cascading Reasoning
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Stuckenschmidt, H., Ceri, S., Della Valle, E., & Van Harmelen, F.
(2010). Towards expressive stream reasoning
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Cascading Reasoning vs State-of-the-art
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Stuckenschmidt, H., Ceri, S., Della Valle, E., & Van Harmelen, F.
(2010). Towards expressive stream reasoning
C-SPARQL
EP-SPARQL
trOWL
ESPER
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Information Integration SystemsThe role of II systems is to provide a uniform view of the data in the sources.
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Integrated Conceptual Model (ICM)
Mappings
Data Sources
Query
Wrappers
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Information Integration Systems
Integrated Conceptual Model (ICM), i.e., a common vocabulary, formally defined, that enables query answering.
Mapping, i.e., (typically) FOL statements that establish links between ICM and data sources.
Wrapper, i.e., interfaces to reinterpret the data source into a data model that enables the mapping.
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at a glance
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Cascading Reasoning VS Information Integration
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Stuckenschmidt, H., Ceri, S., Della Valle, E., & Van Harmelen, F.
(2010). Towards expressive stream reasoning
z
ICM
z Wrappingz Mapping
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Research Plan
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RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Research Questions
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Q.1, Can we extend the mapping language to include time-related operators (e.g. windows) and engines operational semantics?
Q.2, Can we extend the ontological language to include time operators without degenerate into intractability?
Q.3, Can we enable a systematic comparative research approach for stream reasoners?
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Q.1, Can we extend the mapping language to include time-related operators (e.g. windows) and engines operational semantics?
Q.2, Can we extend the ontological language to include time operators without degenerate into intractability?
Research Questions
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Q.3, Can we enable a systematic comparative research approach for stream reasoners?
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Research Questions: Q.1
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Stuckenschmidt, H., Ceri, S., Della Valle, E., & Van Harmelen, F.
(2010). Towards expressive stream reasoning
Q.1
relates with rewriting and interpretation
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Q.1 Research Plan
(i) include the continuous semantics to enable continuous querying over virtual RDF Stream data sources;
(ii) include time aware operators, e.g. windows, to enable rewriting over continuous query languages e.g. EPL;
(iii) enable the description of stream processors execution semantics.
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Extending mapping language to
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Research Questions: Q.1
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Stuckenschmidt, H., Ceri, S., Della Valle, E., & Van Harmelen, F.
(2010). Towards expressive stream reasoning
Q.2
relates with reasoning and abstraction
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Q.2 Research Plan
(i) identify meaningful OWL 2 DL fragments for Stream Reasoning.
(ii) consider temporal extension of DLs that do not degenerate to intractability.
(ii) exploit time-related operators typical of complex event processing or event calculus to provide rule based reasoning.
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Extend the ICM language to
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Evaluation Plan
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RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
A good evaluation
by Nico Matentzoglu
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RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Stream Reasoning Benchmarking
Mostly related to RDF Stream Processing
Focused on query answering
Limited Entailment (RDFS subsets)
Lack of expressive benchmarks
Lack of shared approaches
No absolute winner (RSP)
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RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Research Questions
Q.1, Can we extend the mapping language to include time-related operators (e.g. windows) and engines operational semantics?
Q.2, Can we extend the ontological language to include time operators with- out degenerate into intractability?
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Q.3, Can we enable a systematic comparative research approach for stream reasoners benchmarking?
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Benchmark Principles
The goal of a domain specific benchmark is to foster technological progress by guaranteeing a fair assessment.
Jim Gray, The Benchmark Handbook for Database and Transaction Systems, 1993
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RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Experiment Design
for Stream Reasoning
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is the engine used as subject in the experiment;
is an ontology and any data not subject to change during the experiment.
is the description of the input data streams:
is the set of continuous queries registered into the engine
is the set of key performance indicators (KPIs) to collect.
The result of the execution of an experiment is a Report that captures the engine dynamics.
E
T
Q
D
K
R
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Test Stand Architecture
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RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
RSP Baselines
The minimal meaningful approaches to realise an
RSP engine
Pipeline of DSMS and a reasoner;
Support reasoning under the ρDF entailment regime;
Data can flows from the DSMS to the reasoner via snapshots (i.e. Figure 2-A) or differences ( Figure 2-B);
They exploit absolute time, i.e. their internal clock can be externally controlled.
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RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Comparative Analysis Enabled
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RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Comparative Analysis Enabled
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RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano) 33
Achievements and Future Works
Conclusion
RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Lessons Learned
- Stream Reasoning benchmarking requires further investigations
- RSP research is mature (active w3c group), but still its role can be further investigated
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RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Achievements
- Publication: Heaven: a framework for systematic comparative research approach for RSP engines (ESWC 2016)
- Promising work for semantic Complex Event Processing
- First steps towards a “naïve” implementation of cascading reasoning (collaboration with UGENT)
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RR - 2016 - Aberdeen - Riccardo Tommasini (Politecnico di Milano)
Questions?Email: [email protected] Twitter: @rictomm Github: riccardotommasini Web: streamreasoning.org
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