Do ”Web of Things Platforms” Truly Follow the Web of Things?
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- The document analyzes whether existing Web of Things platforms truly follow the principles of the Web of Things. - It identifies 12 key elements of the Web of Things, including device discovery, integration with the web, use of RESTful services, and security. - It then evaluates 26 popular Web of Things platforms against these 12 elements. It finds that none of the platforms fully satisfy more than 10 of the 12 elements, and many platforms fail to properly address important elements like device discovery and security. - The document concludes that while existing platforms provide some Web of Things capabilities, no platform currently offers a complete solution that covers all aspects of integrating physical devices with web clients and services as envisioned by the Web of
![• Step 3 & 4: Analyze and examine selected platforms to verify their
compliance to the common characteristics of WoT platforms
• Device Discovery
• The ”Achilles heel” of WoT
• The large majority of the platforms (21 out of 26) do not implement or adopt
any discovery protocol.
• From the few platforms dealing with discovery of devices, almost all focus on
local device discovery at the same physical space.
• TinyREST and Dynamix use UPnP
• SOCRADES uses WS-Discovery.
• HomeWeb [6] has implemented a lightweight equivalent of WS-Discovery,
more appropriate for the WoT.
• The only platform focusing on global discovery of devices on the web is
SpitFire, which employs an interesting discovery technique based on web
crawlers.
Analysis of Web of Things Platforms](https://image.slidesharecdn.com/wotplatformspresentation-161214221557/85/Do-Web-of-Things-Platforms-Truly-Follow-the-Web-of-Things-15-320.jpg)
Do ”Web of Things Platforms” Truly Follow the Web of Things?
- 1. Do Web of Things Platforms Truly Follow Web of Things? Unit for Reasoning, Querying and Stream Processing Insight Centre for Data Analytics, National University of Ireland, Galway Andreas Kamilaris, Ali Intizar World Forum – IoT 2016 Reston, VA, USA- December 12-14, 2016
- 2. https://www.w3.org/WoT/images/iot.png Web of Things • Designed to connect “things” to the Web • A combination of • Approaches • Software Architectures • Interfaces
- 3. https://www.w3.org/WoT/images/iot.png • Increase Interoperability among IoT platforms • Mitigate Silo Architecture • Avoid Multiple and Conflicting Standards • Global and Easy Discovery of Devices Why we need Web of Things?
- 4. • Few of the emerging WoT platforms • Sorcades • ThingWorx • SpitFire • Evrythng • Open.Sen.se • WoTKit • Auto WoT • Xively Web of Things Platforms
- 5. • Our Motivation • What are the common characteristics that identify the Web of Things platforms? • What are the must have functionalities to make a platform WoT enabled? • Do WoT platforms follow Web Standards? • What is the status of the state of the art WoT platforms? • How can we improve WoT platforms? • How can we help to increase the speed of the evolution of WoT platforms? Analysis of Web of Things Platforms
- 6. • Our Methodology: • Step 1: Identify the basic elements of the WoT, based on the state of art literature and pioneering work in the field. • Step 2: Locate the most popular platforms and frameworks which claim to be ready for the WoT. • Step 3: Analyze these platforms according to each of the foundational WoT elements, as identified in Step 1. • Step 4: Consider each of the basic elements of the WoT one by one, examining how they have been addressed/satisfied by those platforms. Analysis of Web of Things Platforms
- 7. • Step 1: Identify the basic elements of the WoT • Device Discovery: • Locally (within the same physical space) • Globally (through Web) • Integration to the Web: • Locally (within the same physical space) • Globally (through Web) Analysis of Web of Things Platforms
- 8. • Step 1: Identify the basic elements of the WoT • Restful Services between the devices/Things • Restful Services between the WoT platforms Analysis of Web of Things Platforms
- 9. • Step 1: Identify the basic elements of the WoT • Supported Data Formats • Multiples Response Types Analysis of Web of Things Platforms
- 10. • Step 1: Identify the basic elements of the WoT • Security • Authorization • Authentication • Message Encryption Analysis of Web of Things Platforms
- 11. • Step 1: Identify the basic elements of the WoT • Semantic Description • Service Semantics: semantic description of services e.g. what they provide and how to access them. • Data Semantics: semantic description of data produced by the devices e.g. what is data schema and how it is represented. Analysis of Web of Things Platforms
- 12. • Step 1: Identify the basic elements of the WoT • Mashup Services • Create enhanced services by mash-up of the existing services • Service re-usability and sharing • Availability of services for re-use and share among multiple users • Syndication Techniques/Web Messaging • Create enhanced services by mash-up of the existing services Analysis of Web of Things Platforms
- 13. • Step 2: Locate the most popular Web of Things Platforms • Web of Things Platforms • 26 most popular Web of Things Platforms • Popularity is defined in terms of academic popularity e.g. more than 15 citations for the relevant research articles • A combination of academic research proposal and commercial products/startups Analysis of Web of Things Platforms
- 14. • Step 2: Locate the most popular Web of Things Platforms Analysis of Web of Things Platforms No Platform/Project 1 TinyREST 2 pREST 3 SOCRADES 4 HomeWeb 5 SenseWeb 6 Sense2Web 7 Sensor.Network 8 SensorBase 9 Sensorpedia 10 Social Access Controller (SAC) No Platform/Project 11 WoT framework for CPS 12 WebPlug 13 AutoWoT 14 SenseBox 15 Akribopoulos et al. 16 SemSense 17 VO Framework 18 WoTKit 19 GaaS 20 Dynamix No Company 21 Xively 22 Evrythng 23 Open.Sen.se 24 ThingWorx 25 Paraimpu 26 SpitFire
- 15. • Step 3 & 4: Analyze and examine selected platforms to verify their compliance to the common characteristics of WoT platforms • Device Discovery • The ”Achilles heel” of WoT • The large majority of the platforms (21 out of 26) do not implement or adopt any discovery protocol. • From the few platforms dealing with discovery of devices, almost all focus on local device discovery at the same physical space. • TinyREST and Dynamix use UPnP • SOCRADES uses WS-Discovery. • HomeWeb [6] has implemented a lightweight equivalent of WS-Discovery, more appropriate for the WoT. • The only platform focusing on global discovery of devices on the web is SpitFire, which employs an interesting discovery technique based on web crawlers. Analysis of Web of Things Platforms
- 16. • Step 3 & 4: Analyze and examine selected platforms to verify their compliance to the common characteristics of WoT platforms • Integration to the Web • Satisfied only by a subset of the platforms (10 out of 26). • pREST, SOCRADES, Akribopoulos et al. and the VO Framework employ embedded HTTP servers on SunSPOTs and Arduinos. • HomeWeb and SpitFire use 6LoWPAN and CoAP. • SenseWeb and SAC use gateways • Evrythng developed its own embedded device toolkits for helping developers build their own WoT applications. Analysis of Web of Things Platforms
- 17. • Step 3 & 4: Analyze and examine selected platforms to verify their compliance to the common characteristics of WoT platforms • Restful Services Devices • 10 out of the 26 platforms suggest a RESTful interaction with WoT devices. • Gateways are the default option for constrained things such as RFID tags, QR codes and barcodes. • SenseWeb supports interaction through WS-* services. • SOCRADES offers also DPWS-based support. • The rest of 16 platforms offer only indirect ways to interact with physical devices through RESTful interfaces. Analysis of Web of Things Platforms
- 18. • Step 3 & 4: Analyze and examine selected platforms to verify their compliance to the common characteristics of WoT platforms • Restful Services Platforms • Most satisfied requirement by the platforms (18 out 26). • Platforms provide RESTful APIs for users to interact with WoT devices/services and data collected. • SenseWeb and SensorBase offer interaction based on WS-*. • The on-going battle REST Vs. WS-* . Analysis of Web of Things Platforms
- 19. • Step 3 & 4: Analyze and examine selected platforms to verify their compliance to the common characteristics of WoT platforms • Data Formats • Most platforms employ XML, JSON, CSV and HTML. • XML is the most widely used (17 out of 26 platforms). • Atom (Sensorpedia, WebPlug and Xively), XHTML (SOCRADES) • GeoRSS (Sensorpedia), KML (WoTKit), • GeoML (WoT framework for CPS), EEML and RSS (Xively). • RDF is employed in Sense2Web, the WoT framework for CPS and in SpitFire. • SenseWeb, Open.Sen.se and ThingWorx use only plain text! Analysis of Web of Things Platforms
- 20. • Step 3 & 4: Analyze and examine selected platforms to verify their compliance to the common characteristics of WoT platforms • Multiple Representation of Response Types • A powerful element of the WoT is the opportunity to negotiate among multiple representations of the HTTP responses from things, their gateways or the platforms themselves. • Negotiation should be based on various well-known data formats on Web. • From the 26 platforms, only 16 satisfy this important requirement. Analysis of Web of Things Platforms
- 21. • Step 3 & 4: Analyze and examine selected platforms to verify their compliance to the common characteristics of WoT platforms • Security • 14 platforms do not consider security at all. • HomeWeb, SenseWeb, SensorBase and Open.Sen.se offer only basic user authentication. • Sensor.Network, Xively, Evrythng, ThingWorx and Paraimpu require an API key on the HTTP header, to call RESTful services. • Sensor.Network and Paraimpu support HTTP Secure (HTTPS), • Sensorpedia supports OpenID. • OAuth 2.0 is adopted by Sensorpedia, SAC and Evrythng. • Xively is the platform with the most complete security profile, supporting among others TLS and DTLS for privacy and data integrity during message communication. Analysis of Web of Things Platforms
- 22. • Step 3 & 4: Analyze and examine selected platforms to verify their compliance to the common characteristics of WoT platforms • Service Semantics • More than half (14 out of 26) platforms provide semantics for interacting with their APIs and devices. • SOCRADES and GaaS adopt WSDL, HomeWeb proposes WADL. • HomeWeb and SAC also use HTML links to navigate between services. • AutoWoT adopts microformats. • SenseBox prefers the OGC Sensor Web Enablement (SWE) standards • SpitFire uses sensor meta-data to describe sensors’ services. • Few research-based platforms (Sensor.Network, WoTKit), as well as all commercial platforms (Xively, Evrythng, Open.Sen.se, ThingWorx and Paraimpu) provide detailed API documentations or SDKs in various programming languages. Analysis of Web of Things Platforms
- 23. • Step 3 & 4: Analyze and examine selected platforms to verify their compliance to the common characteristics of WoT platforms • Data Semantics • 16 out of 26 platforms do not provide any semantic descriptions of the data exchanged between the things/platform and the user. • SensorBase describes sensor data by SensorML, Akribopoulos et al. use WiseML. • Sensor.Network employs XML descriptors. • The rest platforms (pREST, Sense2Web, SenseBox, SemSense, VO Framework, Evrythng and SpitFire) employ Semantic Web technologies such as RDF, OWL, SPARQL as well as the OGC Observations and Measurements (O&M) standard. • The commercial platforms do not employ semantics, with the exception of Evrythng. Analysis of Web of Things Platforms
- 24. • Step 3 & 4: Analyze and examine selected platforms to verify their compliance to the common characteristics of WoT platforms • Mashups • Fifteen platforms provide some mashup functionality (e.g. sensor maps, plots, widgets) • Only HomeWeb, WoTKit, GaaS, Evrythng, Open.Sen.se, ThingWorx and Paraimpu offer mashup builders/composers. • Mashup editors seem to be recognized by the commercial initiatives as an integral feature provided to their end users. Analysis of Web of Things Platforms
- 25. • Step 3 & 4: Analyze and examine selected platforms to verify their compliance to the common characteristics of WoT platforms • Sharing and Re-usability • Sharing of WoT devices and services among online contacts is a practice not adopted by most platforms, except from HomeWeb, SAC and Paraimpu. • HomeWeb shares things and their services among Facebook friends. • SAC delegates access to things based on Facebook and Twitter APIs (to locate trusted contacts). • Paraimpu shares things among other Paraimpu users. Analysis of Web of Things Platforms
- 26. • Step 3 & 4: Analyze and examine selected platforms to verify their compliance to the common characteristics of WoT platforms • Syndication Techniques/ Web Messaging • Fifteen platforms employ syndication and/or publish/subscribe messaging techniques for interacting with things. • Sensorpedia and SAC use ATOMPub as a syndication. • TinyREST and pREST use dedicated subscription services on things. • The concept of Web hooks is employed in HomeWeb, Sensor.Network, SenseBox (push notifications), WebPlug, Open.Sen.se and Paraimpu. • SOCRADES and GaaS select WS-Notification (from WS-*). • VO Framework proposes the OSGi Eventing Service. • Commercial platforms prefer more scalable publish/subscribe messaging brokers such as MQTT (Xively and Evrythng) and XMPP. Analysis of Web of Things Platforms
- 27. No Platform/Project 1 TinyREST 2 pREST 3 SOCRADES 4 HomeWeb 5 SenseWeb 6 Sense2Web 7 Sensor.Network 8 SensorBase 9 Sensorpedia 10 Social Access Controller (SAC) No Platform/Project 11 WoT framework for CPS 12 WebPlug 13 AutoWoT 14 SenseBox 15 Akribopoulos et al. 16 SemSense 17 VO Framework 18 WoTKit 19 GaaS 20 Dynamix No Company 21 Xively 22 Evrythng 23 Open.Sen.se 24 ThingWorx 25 Paraimpu 26 SpitFire Supporting 2-3 Elements Supporting 4-6 Elements Supporting 7-9 Elements Supporting 10 or more Elements Conclusion
- 28. • Global discovery on the WoT is still an open issue. • Description of services is addressed mainly by the commercial approaches. • Data semantics is supported mostly by the research initiatives, by means of Semantic Web technologies. • Evrythng is the most complete platform from the ones reviewed. • None of the 26 platforms fully adopt more than 10 of the 12 basic elements identified. There do not exist any complete WoT platforms yet, covering the whole cycle from physical things to web clients, addressing effectively all the issues of discovery, interaction, service/data description, messaging, security, sharing and mashup creation. Conclusion
Editor's Notes
- #28: Evrythng and HomeWeb are the platforms closer to the concepts of the WoT, both scoring 10/12. SemSense and Dynamix develop only two elements, TinyREST and Akribopoulos et al. support only three, while the WoT framework for CPS, Sense2Web, SensorBase, Sensorpedia, AutoWoT and WoTKit provide only five of the 12 elements.
- #29: Hence, we suggest that academia and enterprise should use the ”Web of Things” label more moderately, with some caution