Transcript of "Coordination of Resource-Constrained Devices through a Distributed Semantic Space"
Coordination of Resource-Constrained Devices through a Distributed Semantic Space ´ Aitor Gomez-Goiri DeustoTech - Deusto Institute of Technology, University of Deusto http://www.morelab.deusto.es February 20, 2013
Tuple Spaces Coupling ⇓ nodes coordinate writing and reading information in a common spaceCoordination of Constrained devices What do I do? 11 / 42
Tuple Spaces Coupling ⇓ nodes coordinate writing and reading information in a common space Location autonomy Reference autonomy Time autonomyCoordination of Constrained devices What do I do? 11 / 42
The Semantic Web Coupling on nodes’ internal data-schema ⇓ Add semantic to achieve application-level interoperability BackupCoordination of Constrained devices What do I do? 12 / 42
Tuple Spaces Semantic Web Mobile WoT comp Ubiquitous computing
Challenge Adapt TSC for resource constrained devicesCoordination of Constrained devices Lightweight TSC middleware 15 / 42
Challenge Adapt TSC for resource constrained devices 1. Knowledge dissemination 2. Compatibility with REST (& the WoT)Coordination of Constrained devices Lightweight TSC middleware 15 / 42
Knowledge dissemination Too much load for small devices Delegate into intermediaries Everything related wih the semantic Devices manage their own semantic dataCoordination of Constrained devices Lightweight TSC middleware 16 / 42
Compatibility with the WoT/REST Provide content using semantic format RESTfully Compatible with WoT REST* TSC ROA x x Resources x x identiﬁed by URIs GET, PUT, Operations Write, read, take POST, DELETE Representation HTML, Json,... Full semantics On top of that, we build a TSC middlewareCoordination of Constrained devices Lightweight TSC middleware 17 / 42
Starting point (assumptions) Each device manages its own information The space is distributed among all the participants Each device interrogates othersCoordination of Constrained devices Lightweight TSC middleware 20 / 42
Who to query? To all (naive)Coordination of Constrained devices Lightweight TSC middleware 21 / 42
Who to query? To whoever has a relevant answer for me ⇓ need to know about the information others haveCoordination of Constrained devices Lightweight TSC middleware 21 / 42
What should a node know from the rest? General concepts or terminology (TBox) implies sharing less information ( the speciﬁc knowledge, ABox, changes too frequently ) BackupCoordination of Constrained devices Lightweight TSC middleware 22 / 42
Energy-aware architecture Share clues through an intermediary dynamic role chosen according to its capacities get clues make clues send clues directly access to dataCoordination of Constrained devices Lightweight TSC middleware 23 / 42
Goal 300000 300000 ours 250000 250000 nb 200000 200000 active time / node active time / node 150000 150000 100000 100000 50000 50000 0 nb ours 0 xbee foxg20galaxy_tab server Strategy Types of devices (16% less energy consumed without activity in a FoxG20)Coordination of Constrained devices Lightweight TSC middleware 24 / 42
Conclusions 1. Indirect communication to ease developers tasks 2. Promote end-to-end search 3. Architecture driven by energy needs 4. Light reasoners for small devices still neededCoordination of Constrained devices Conclusions 25 / 42
Future work Enhance the mechanisms to act on the space Consider queries for ABox knowledge Further tests in non-prototipical real-world scenarios Continue exploring its feasibility in other platformsCoordination of Constrained devices Conclusions 26 / 42
Bibliography I Payam Barnaghi, Wei Wang, Cory Henson, and Kerry Taylor. Semantics for the internet of things. International Journal on Semantic Web and Information Systems, 8(1):1–21, 2012. George Coulouris, Jean Dollimore, Tim Kindberg, and Gordon Blair. Distributed Systems: Concepts and Design. Addison Wesley, 5 edition, 2012. 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.Coordination of Constrained devices Bibliography 28 / 42
Bibliography IICoordination of Constrained devices Bibliography 29 / 42
Conceptual classiﬁcation Applications, services Remote invocation Indirect communication (e.g. REST or WS.*) (e.g. Tuple Spaces) Middleware layers Underlying interprocess communication (sockets, message passing, multicast support, overlay networks) Platform (operating system + hardware) [CDKB12]Coordination of Constrained devices Backup slides 31 / 42
The Semantic Web in short 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] BackCoordination of Constrained devices Backup slides 32 / 42
Semantics alone are not enough Providing semantic descriptions alone does not provide semantic interoperability. [BWHT12] Agreement on ontological deﬁnitions ontology mapping and matching use of reference upper-level ontologies Semantics need to be processed and analyzed interpret and create meaningful abstractions effective reasoning and processing Should the ontologies be simpler and light weight for IoT? BackCoordination of Constrained devices Backup slides 33 / 42
TBox TBox contains knowledge describing general properties of concepts or terminology. [NB03] E.g. the device type or the elements it is made of. BackCoordination of Constrained devices Backup slides 35 / 42
ABox ABox contains knowledge speciﬁc to the individuals of the domain of discourse. [NB03] E.g. the mobile phone brand or the temperature sensed by a thermometer. BackCoordination of Constrained devices Backup slides 36 / 42
Application 1: Security Security application monitors parameters E.g. temperature, humidity & CO2 concentration Sensors deployed in an industrual facility Generates alarms different priorities They are displayed in different devices E.g. visual and auditory alarms or in the managers the phone Using standards ontologies such as: SSN, SWEETCoordination of Constrained devices Backup slides 37 / 42
Application 2: Home automation Devices deployed on an ofﬁce: sensors and actuators An application in a smartphone stores user’s preferences A node generates tasks to regulate the temperature Using standards ontologies such as: SSN, MUO, RECOCoordination of Constrained devices Backup slides 38 / 42
Interoperability Both applications use SSN ontology Even if they were not designed with that purpose... App1 transparently uses App2’s data and vice versa BackCoordination of Constrained devices Backup slides 39 / 42
Energy consumption 700 Average power consumption (mW) 600 500 400 300 200 100 0 Inactivity Period with Reasoning period period continuous requests BackCoordination of Constrained devices Backup slides 40 / 42
Use of Semantic Gateways Sensors directly Use of semantic provide data gateway Strong nodes Really constrained Most updated Possible Caching More privacy control Autonomy Dependency (less ﬂexible)Coordination of Constrained devices Backup slides 41 / 42
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. * OpenStreetMap, Universidad de Deusto, Amortize, and Marco Crupi.
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