Assessing data dissemination strategies

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Assessing data dissemination strategies within Triple Spaces on the Web of Things (presentation made on esIoT 2012)

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Assessing data dissemination strategies

  1. 1. Assessing data dissemination strategieswithin Triple Spaces on the Web of Things esIoT 2012 ´ ´ ˜ Aitor Gomez-Goiri, Diego Lopez-de-IpinaDeustoTech - Deusto Institute of Technology, University of Deusto http://www.morelab.deusto.es July 4, 2012
  2. 2. Outline Introduction Data dissemination strategies Evaluation ConclusionsAssessing data dissemination strategies 2 / 57
  3. 3. Outline Introduction Data dissemination strategies Evaluation ConclusionsAssessing data dissemination strategies Introduction 3 / 57
  4. 4. The Web of Things Growing connectivity of everyday objects. WoT to integrate things. Scalable interaction, integration with the web world... But also inherits problems from the web world! Lack of expressiveness and human orientation The Semantic Web enables sharing knowledge across different applicationsAssessing data dissemination strategies Introduction 4 / 57
  5. 5. The Semantic Web The vision of the Semantic Web is to extend principles of the Web from documents to data. Data should be accessed using the general Web architecture using, e.g., URI-s; data should be related to one another just as documents (or portions of documents) are already. This also means creation of a common framework that allows data to be shared and reused across application, enterprise, and community boundaries, to be processed automatically by tools as well as manually, including revealing possible new relationships among pieces of data. [Con11]Assessing data dissemination strategies Introduction 5 / 57
  6. 6. The Semantic Web The vision of the Semantic Web is to extend principles of the Web from documents to data. Data should be accessed using the general Web architecture using, e.g., URI-s; data should be related to one another just as documents (or portions of documents) are already. This also means creation of a common framework that allows data to be shared and reused across application, enterprise, and community boundaries, to be processed automatically by tools as well as manually, including revealing possible new relationships among pieces of data. [Con11]Assessing data dissemination strategies Introduction 6 / 57
  7. 7. Triple Space Computing Describes the knowledge shared using the SW 2 applications using standard ontologies can interact among them automatically enriching one each other. Space-based computing time autonomy space autonomy reference autonomyAssessing data dissemination strategies Introduction 7 / 57
  8. 8. Goal How to realize this shared blackboard in the IoT?Assessing data dissemination strategies Introduction 9 / 57
  9. 9. Outline Introduction Data dissemination strategies Centralization Negative broadcasting Gossiping based strategy Evaluation ConclusionsAssessing data dissemination strategies Data dissemination strategies 10 / 57
  10. 10. Centralization in short r = |Q| + wf .t.(|N| − 1) (1)Assessing data dissemination strategies Data dissemination strategies 13 / 57
  11. 11. Negative broadcasting in short r = |Q|.(|N| − 1) (2)Assessing data dissemination strategies Data dissemination strategies 16 / 57
  12. 12. How to improve the NB? Reducing the amount of receivers for a query.Assessing data dissemination strategies Data dissemination strategies 17 / 57
  13. 13. Problem: how to perfectly predict them without knowing all what they know?
  14. 14. TBox and ABox According to Nardi and Brachman [NB03]... TBox contains the knowledge which describes general properties of concepts or terminology. ABox contains knowledge that is specific to the individuals of the domain of discourse.Assessing data dissemination strategies Data dissemination strategies 22 / 57
  15. 15. In other words... With TBox we can describe the type of devices there are in the world or the sensors they have. With ABox we can specify that HTC is a mobile brand or that the sensed temperature is 3o C.Assessing data dissemination strategies Data dissemination strategies 23 / 57
  16. 16. TBox and ABox in IoT scenarios? Mobile devices: user profile,... Sensors and actuators The structure of the data barely changes!Assessing data dissemination strategies Data dissemination strategies 24 / 57
  17. 17. Our proposal We can assume that all the nodes have or can easily obtain the TBox information. Nodes gossip the classes of concepts (rdf:type) shared by other nodes.Assessing data dissemination strategies Data dissemination strategies 25 / 57
  18. 18. Subject Predicate Objectwot:meas1 rdf:type ssn:N02Observationwot:meas1 ssn:observedProperty sweet:NO2wot:meas1 ssn:observationResult wot:outpt1wot:outpt1 ssn:hasValue wot:val1wot:val1 ssb:QuantityValue 17wot:val1 dul:isClassifiedBy muo-ucum:microgram-per-cubic-meter... ... ...
  19. 19. Subject Predicate Objectwot:meas1 rdf:type ssn:N02Observationwot:meas1 ssn:observedProperty sweet:NO2wot:meas1 ssn:observationResult wot:outpt1wot:outpt1 ssn:hasValue wot:val1wot:val1 ssb:QuantityValue 17wot:val1 dul:isClassifiedBy muo-ucum:microgram-per-cubic-meter... ... ...
  20. 20. Outline Introduction Data dissemination strategies Evaluation ConclusionsAssessing data dissemination strategies Evaluation 29 / 57
  21. 21. Remember We wanted to know which strategy fits better for IoT. Otsopack: our publicly available TSC middleware which uses HTTP. Therefore: communication between nodes was point to point and exchanges data RDF triples.Assessing data dissemination strategies Evaluation 30 / 57
  22. 22. Methodology Discovery process was ignored. The Semantic Sensor Network Ontology (SSN). Datasets from the University of Utah and the University of Deusto. Measures taken from real embedded web servers. Simpy.Assessing data dissemination strategies Evaluation 31 / 57
  23. 23. Performance Metrics Precision: the fraction of nodes which answered relevant results. Recall: the fraction of relevant answers returned. Response time.Assessing data dissemination strategies Evaluation 32 / 57
  24. 24. Outline Introduction Data dissemination strategies Evaluation ConclusionsAssessing data dissemination strategies Conclusions 36 / 57
  25. 25. Conclusions Need of a gossiping approach. Increase the precision. Simulate specific scenarios from the literature.Assessing data dissemination strategies Conclusions 37 / 57
  26. 26. Assessing data dissemination strategies Conclusions 38 / 57
  27. 27. Bibliography World Wide Web Consortium. W3c semantic web faq, August 2011. D. Nardi and R.J. Brachman. An introduction to description logics. The description logic handbook: theory, implementation, and applications, pages 1–40, 2003.Assessing data dissemination strategies Bibliography 39 / 57
  28. 28. Assessing data dissemination strategies Backup slides 40 / 57
  29. 29. Semantic Web exampleAssessing data dissemination strategies Backup slides 41 / 57
  30. 30. Write public String write(String spaceURI, Graph ITriples) throws TSException;Assessing data dissemination strategies Backup slides 42 / 57
  31. 31. Read public Graph read (String spaceURI, String graphURI, long timeout) throws TSException; public Graph read (String spaceURI, Template template, long timeout) throws TSException;Assessing data dissemination strategies Backup slides 43 / 57
  32. 32. Take public Graph take (String spaceURI, String graphURI, long timeout) throws TSException; public Graph take (String spaceURI, Template template, long timeout) throws TSException;Assessing data dissemination strategies Backup slides 44 / 57
  33. 33. Query public Graph query(String spaceURI, Template template) throws TSException;Assessing data dissemination strategies Backup slides 45 / 57
  34. 34. Reasoning Device TBox ABox Regular computer 2.787 0.045 (Sesame 2.6.4) Samsung Galaxy Tab 17.342 0.225 (Sesame 2.4.2) FoxG20 48.939 1.443 (Fuxi)Assessing data dissemination strategies Backup slides 46 / 57
  35. 35. Our realization of the ideas towards this adaptation are incarnated on Otsopack Open source project
  36. 36. Otsopack Layers Each Otsopack instance.Assessing data dissemination strategies Backup slides 48 / 57
  37. 37. About HTTP and TSC The HTTP verbs retrieve, create, modify or delete web resources The TS primitives retrieve, create, modify or delete RDF graphs on a space (right, to be honest TS also offers a query, which works at space level)Assessing data dissemination strategies Backup slides 49 / 57
  38. 38. A RESTful HTTP API To expose TS querying primitives HTTP status codes Using content negotiationAssessing data dissemination strategies Backup slides 50 / 57
  39. 39. Discovery Registry based discovery Multicast based implemented Easy to adopt new ones: DNS, mDNS, lmDNS etc.Assessing data dissemination strategies Backup slides 51 / 57
  40. 40. TSC API in depth HTTP request URL GET /{sp}/query/wildcards/{s}/{p}/{o-uri} /{sp}/query/wildcards/{s}/{p}/{o-type}/{o-value} GET /{sp}/graphs/{g} GET /{sp}/graphs/wildcards/{s}/{p}/{o-uri} /{sp}/graphs/wildcards/{s}/{p}/{o-type}/{o-value} DELETE /{sp}/graphs/{g} DELETE /{sp}/graphs/wildcards/{s}/{p}/{o-uri} /{sp}/graphs/wildcards/{s}/{p}/{o-type}/{o-value}Assessing data dissemination strategies Backup slides 52 / 57
  41. 41. XBee gateway platform ConnectPort R X2 (XBee to IP gateway) RAM: 8MB Platform version: Python 2.4 REST libraries: Python Std Lib Semantic libraries: NoneAssessing data dissemination strategies Backup slides 53 / 57
  42. 42. Case of study 1: XBee We developed a restricted middleware version using Python With more than 15 concurrent requests problems were experiencedAssessing data dissemination strategies Backup slides 54 / 57
  43. 43. FoxG20 platform Processor: 400Mhz Atmel ARM9 RAM: 64MB Platform version: Python 2.5 REST libraries: Python Std Lib Semantic libraries: FuxiAssessing data dissemination strategies Backup slides 55 / 57
  44. 44. Case of study 2: FoxG20 Python implementation used Because is lighter Does not implement all the modules defined This may be desirable for less powerful devices Reasoning took a long time TBox: x17 regular computer, x2 galaxy tab ABox: x32 - x6 galaxy tab ⇓ should be limited to special occasionsAssessing data dissemination strategies Backup slides 56 / 57
  45. 45. All rights of images are reserved by theoriginal owners*, the rest of the content is licensed under a Creative Commons by-sa 3.0 license. * Kit (practicalowl), Stefan Paunovi´ , Amortize and Marco Crupi Digi c International Inc. and Acme systems.

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