Discovery and Search

T-106.5840 Internet of Things Matias Piispanen [email protected]

October 6, 2011 Contents

• Introduction • Search in Internet • Search in Internet of Things • EPCglobal • Conclusion

Introduction

Search problems in IoT: • High amount of devices • Heterogenous devices – RFID tags, sensors, actuators, ... • Distributed databases • Dynamic data • What are we searching?

Search in Internet – Case

• Googlebot crawls documents on the web – Static content – Only a part of the whole web!

• Found pages indexed in – Sparse, distributed and multidimensional sorted map

• PageRank

“Google” for IoT?

• Crawling is not possible – No links – Data is real-time

• Different ways of updating sensor data – Push – Pull – Sensor Ranking

Sensor Ranking

• Sensors data is sorted based on a prediction model – For example data is often cyclic or recent data is probably still accurate

• Pull data one by one until enough desirable results are found

• Better scalability than push and pull approaches – Still limited scalability

Tracking Physical Objects

• Objects need to be uniquely identified – RFID, barcodes, ...

• Objects are typically not connected to a network

• Local data – Global Search

• Distributed data

Supply Chain Management

EPCglobal Network

• Standard for sharing EPC (Electronic Product Code) related data • EPC Information Services (EPCIS) – Stores EPC Events – Offers a query interface • EPC Discovery Services (EPCDS) • Object Name Service (ONS)

EPCglobal Network Architecture

EPC Information Services

• Repository for EPC read events • Query interface

• EPC Read Event - What, Where, When, Why? – EPC Number – Event Time – Action – Location – Other data

Discovery Service Architecture

• There are many possibilities for the architecture of a Discovery Service – Directory of Resources – Notification of Resources – Notification of Clients – Query Propagation – Aggregating Discovery Service – P2P

• Different approaches to security

EPC Discovery Service

• EPCIS's inform EPCDS about the first read event for each EPC – EPC Number – URL of the EPCIS – Certificate of the company – Visibility – Timestamp • Supports ad hoc queries and registering for standing queries • Handles security concerns

Object Name Service (ONS)

• DNS-based service that resolves resources to an EPC

EPC Numbering Scheme:

• Granularity at product type level – resolves the EPC number to only one EPCIS

Search Problems

• Scalability is again a problem. There can't be just one discovery service • Not all EPCIS's are necessarily part of the same EPCDS network • It is unclear how to locate the correct discovery service given an EPC – Object Name Services – P2P • Searching only possible using the EPC number

Conclusion

• Scalability is an issue in Internet of Things

• Data is often distributed and not public

• No “One size fits all” solutions

• Global vs Local

Thank You!

References

Ostermaier, B. & Römer, K. & Mattern, F. & Fahrmair, M & Kellerer, W. A Real- Time Search Engine for the Web of Things. Available: http://www.vs.inf.ethz.ch/publ/papers/dyser.pdf

Lorentz, M. & Müller, J. & Schapranow, M. & Zeier, A. & Plattner, H. Discovery Services in the EPC Network. Available: http://www.intechopen.com/source/pdfs/18103/InTech-Discovery_services_in_the_epc_network.pdf

Beier, S. & Grandison, T. & Kailing, K. & Rantzau, R. Discovery Services— Enabling RFID Traceability in EPCglobal Networks. Available: http://www.cse.iitb.ac.in/comad/2006/proceedings/214.pdf

References

Evdokimov, S. & Fabian, B. & Kunz, S. & Schoenemann, N. Comparison of Discovery Services for the Internet of Things. Available: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5504696&isnumber=5504621

Guinard, D. & Karnouskos, S. & Trifa, V. & Dober, B. & Spiess, P. & Savio, D. Interacting with the SOA-based Internet of Things: Discovery, Query, Selection, and On-Demand Provisioning of Web Services. Available: http://vladtrifa.com/research/files/Guinard10tsc.pdf