Page - 170 - in Intelligent Environments 2019 - Workshop Proceedings of the 15th International Conference on Intelligent Environments

AnApproach forMeasuring IoT Interoperability singCausalModeling SebastianKOTSTEINaChristianDECKERb asebastian.kotstein@reutlingen-university.de bchristian.decker@reutlingen-university.de HermannHollerithZentrum,ReutlingenUniversity, D-71034Bo¨blingen,Germany Abstract. Interoperability is an important topic in the InternetofThings (IoT),be- cause thisdomain incorporatesdiverseandheterogeneousobjects, communication protocols and data formats. Many models and classification schemes have been proposed tomake thedegreeof interoperabilitymeasurable - however onlyon the basis of a hierarchical scale. In the course of this paperwe introduce a novel ap- proach tomeasure thedegreeof interoperabilityusingametric scaledquantity.We consider IoT as a distributed system,where interoperable objects exchangemes- sageswitheachother.Under thispremise,we interpretmessagesasoperationcalls andformalize thisviewasacausalmodel.Theanalysisof thismodelenablesus to quantify the interoperablebehaviorof communicatingobjects. Keywords.Internet-of-Things, interoperability,structuralcausalmodel,measurement 1. Introduction The Internet of Things (IoT) transforms ordinary physical objects into so-called smart objects by enriching themwith computing capabilities and connecting these objects to a given communication infrastructure, namely the Internet. Functions and services that were previously only available locally (i.e. within the boundaries of the corresponding physical objects) can nowbe offered to other participants in the IoT environment such that new use cases and applications can be formed out of the composition ofmultiple servicesandfunctions.Furthermore, thesesmartobjectsproduce tonsofdataas theyare able to sense their physical environment in terms of temperature, humidity, light inten- sity and so further, and to share the collected data. Using actors, they are even able to manipulate theenvironment (e.g. a smart light switchallowing to turnon/off the lights). However, interoperability, i.e. theability to seamlesslycommunicate, interact andcoop- eratewith each other, is a critical key factor for realizing such novel IoT applications, as themarket is coined bymany heterogeneous objects, a huge bandwidth of available communicationprotocolsanddataformats,andnumerousrecommendationsforpossible reference architectures [1][2].All these technologies are not always compatible to each other leading to an immensemanual effort for integrating heterogeneous objects into a uniform IoT environment [1]. Therefore, the interoperability challenge is an important topicaddressedbyboth, the researchaswell as in the industry [3][4][5]. U Intelligent Environments 2019 A. Muñoz et al. (Eds.) © 2019 The authors and IOS Press. This article is published online with Open Access by IOS Press and distributed under the terms of the Creative Commons Attribution Non-Commercial License 4.0 (CC BY-NC 4.0). doi:10.3233/AISE190039 170