IoT Semantic Interoperability: Research Challenges, Best Practices, Solutions and Next Steps. - IERC AC4 Manifesto - Present and Future

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1 Manifiesto-V1 IoT Semantic Interoperability: Research Challenges, Best Practices, Solutions and Next Steps - IERC AC4 Manifesto - Present and Future IERC AC

2 Manifiesto-V1 IERC AC4: Service Openness and Inter-operability Issues-Semantic interoperability Project Reference: Activity Cluster: Document Title: IERC AC4 Semantic Interoperability Semantic Interoperability: Research Challenges, Best Practices, Solutions and Next Steps - IERC AC4 Manifesto - Disciplinary area(s) most relevant topics: Future Internet, Internet of Things, Semantic Web. Keywords: Service Openness, Semantic Interoperability, Ontologies Editors: Martin Serrano, Payam Barnaghi and Philippe Cousin Document Id: IERC-AC Deliverable-AC41 File Name: Manifesto-V1.doc Version: V1 Organization: IERC-AC4 Date: Document type: Deliverable-AC4-1 (IERC AC4 Manifesto) Security: Confidential (CO)

3 Manifiesto-V1 EXECUTIVE SUMMARY The European Research Cluster on the Internet of Things 1 (IERC) has created a number of activity chains to initiate close cooperation between the projects addressing the IoT related topics and to form an arena for exchange of ideas and open dialog on important research challenges. The activity chains are defined as work streams that group together partners or specific participants from partners around well-defined technical activities that work on addressing the IERC objectives. As result of the organization of activity chains within the IERC and the continued collaboration and active participation between the ProbeIT, OpenIoT, IoT.est and GAMBAS projects, the managers of those projects were nominated as coordinators of the IERC Activity Chain 4 (AC4) on Interoperability. As activity cluster coordinators, we have defined two streams of activities related to Technical Interoperability: Syntactic and Semantic Interoperability. The results of the current work and collaborations on this topic are presented in this report. One of the main objectives of the IERC AC4 is to specify service openness and standardize interoperability issues when possible. Since standardization needs to ensure interoperability, AC4 not only addresses technological interoperability issues but also semantic interoperability capabilities. Semantics play an important role in many of the EU FP7 projects. The IERCAC4 has allocated efforts on semantic interoperability within the objective to offer the most to the participants in order to obtain the necessary guidance to implement semantic solutions, when it is necessary. By following the enormous interest in Semantics for IoT, as part of the contributions and efforts in the IERC AC4, we have organized and coordinated several AC4 meetings and workshops on related topics. After the IERC AC4 kick-off meeting in Poznan, Poland on 28/10/2012 the IERC AC4 ran a one-day workshop on March 26th 2012 in Paris, France. It was co-located with the PROBEIT project meeting. Short presentations of the AC4 project participants were followed by open discussions to identify challenges on service openness and interoperability issues. The next event was a two-day meeting and hands-on workshop colocated with the IoTWeek June 2012 in Venice, Italy. On October 2012 met at Mandelieu, France at the ETSI plenary meeting and the IERC AC4 co-located a two-day workshop including tutorials focused on semantic modelling, knowledge representation and ontology engineering for the IoT domain. This year IERC AC4 co-located the last meeting with the 19th European Wireless 2013 conference at Guilford, UK that included hands-on sessions on data interoperability and ontology engineering tools. We hope this document contributes to the development of interoperability solutions for the Internet of Things within the IERC AC4 EU-FP7 project members and also supports establishing effective mechanisms to find coordination in terms of semantic interoperability. IERC AC4 Coordinators August

4 Manifiesto-V1 List of Authors (non particular order): Martín Serrano Payam Barnaghi Philippe Cousin NUIG Digital Enterprise Research Institute DERI, OpenIoT UniS, Centre for Communication Systems Research CCSR, IoT.est eglobalmarket Easy Global Market, ProbeIT List of Contributors (non particular order): Manfred Hauswirth NUIG Digital Enterprise Research Institute DERI, Ireland Josiane Javier Parreira NUIG Digital Enterprise Research Institute DERI, Ireland Christian von der Weth NUIG Digital Enterprise Research Institute DERI, Ireland Myriam Leggieri NUIG Digital Enterprise Research Institute DERI, Ireland John Soldatos Athens Institute of Technology AIT, Greece Nikos Kefalakis Athens Institute of Technology AIT, Greece Stavros Petris Athens Institute of Technology AIT, Greece Dimitros Georgakopoulos CSIRO, Australia Arkady Zaslavsky CSIRO, Australia Ali Salehi CSIRO, Australia Karl Aberer Ecole Polytechnique Federale de Lausanne, Switzerland Sofiane Sarni Ecole Polytechnique Federale de Lausanne, Switzerland Reinhard Herzog Fraunhofer IOSB, Germany Panos Dimitropoulos SENSAP Microsystems SENSAP, Greece Nikos Zarokostas SENSAP Microsystems SENSAP, Greece Angele Giuliano AcrossLimits, Malta Johan E. Bengtsson AcrossLimits, Malta Pedro Malo Uninova, Portugal Cesar Viho University of Rennes I, France. Kotis Konstantinos VTT Technical Research Centre of Finland, Finland Hiroyuki Maeomichi NTT Network Innovation Laboratories, Japan Abdur Rahim Create-Net, Italy Charalampos Doukas Create-NET, Italy Davy Preuveneers KU Leuven, Belgium Franck Le Gall INNO Group, France Copigneaux Bertrand INNO Group, France Tobias Muench SAP AG, Germany Oscar Lazaro Innovalia Association, Spain Klaus Moessner UniS, CCSR, United Kingdom Nikolaos Georgantas INRIA, France Valerie Issarny INRIA, France Rob van Kranenburg The Internet of Things Council, United Kingdom Maurizio Pilu TSB, United Kingdom Richard Foggie HOIP, United Kingdom Cheng Sheng Beijing University of Posts and Telecommunications, China Ji Yang Beijing University of Posts and Telecommunications, China Marie Kim ETRI, South Korea. Michael J. Koster Open Source Internet of Things OSIoT, U.S.A. Continue...

5 Manifiesto-V1 List of Project Participants and Contributor Initiatives (non particular order): Project Acronym PROBE-IT OpenIoT GAMBAS IoT.est IoT-I IoT-A ebbits SmartAgriFood icore BUTLER IoT6 Name of Project Pursuing ROadmaps and BEnchmarks for the Internet of Things Open Source Solution for the Internet of Things into the Cloud Generic Adaptive Middleware for Behaviordriven Autonomous Services Internet of Things Environment for Service Creation and Testing Internet Of Things Initiative Internet of Things Architecture Enabling the Business-Based Internet of Things and Services Smart Food and Agribusiness Internet Connected Objects for Reconfigurable Ecosystems Internet of Things at Work Secure and Context Awareness in the IoT Universal Integration of the Internet of Things through an IPv6-based Service Oriented Architecture enabling heterogeneous components interoperability Coordinator Frank Le Gall and Philippe Cousin INNO AG, France Manfred Hauswirth and Martin Serrano National University of Ireland, Galway, Ireland Sandra Kramm, Universitaet Duisburg-Essen, Germany Klaus Moessner and Payam Barnagui University of Surrey, UK Rahim Tafazolli and F. Carrez, University Of Surrey, UK Sebastian LANGE, VDI/VDE-IT Markus Eisenhauer, Fraunhofer FIT, Germany Sjaak Wolfert, Stichting Dienst Landbouwkundig Onderzoek, The Netherlands Raffaele Giaffreda, CREATE-NET, Italy Amine M. Houyou, Siemens AG, Germany Frank Le Gall, INNO AG, France Sébastien Ziegler, Mandat International, Switzerland Initiative Acronym Name of the Initiative Representative IoT Council The Internet of Things Council Rob van Kranenburg WoT China The Web of Things Cheng Sheng and Ji Yang IoT Korea Common Open semantic USN Service Platform Marie Kim IoT Japan IoT USA Open Source Internet of Things OSIoT Michael J. Koster... Continue

6 Manifiesto-V1 If you would like to endorse this document, presentation and content please send your contact details to and Document Endorsements (non particular order): Name Affiliation Project Acronym(s) IERC/Other Project Disclaimer: The objective of this document is merely informative and for dissemination activities and in any case can be considered as evaluation reports or points of reference from any research objective or implementation metrics of the EU FP7 projects. The material and content in this document does not represent any formal position of the European Commission or any Organization members or individuals. The statements included in this document are not final statements and can be modified, updated, changed according with the progress and evolution of the IERC-AC4. Copyrights: The statements included in this document represent the general opinion of the authors and their EU FP7 project consortium and its individuals. The copyrights and use of this intellectual material is for the sole use of dissemination and it is strictly restricted to IERC- AC4 members and their affiliated; if an individual, institution or any type of organization outside IERC-AC4 want to make use of them on behalf of the IERC-AC4, must be submitted for approval of the IERC-AC4 Coordinator and/or IERC-AC4 co-coordinator or at least an authorized IERC-AC4 consortium member

7 Manifiesto-V1 DOCUMENT HISTORY Date Version Status Comments 20.Jun Draft Initial ToC at IoT Week, Venice, Italy 21.Oct Draft Discussion on ETSI M2M IERC AC4 meeting Mandelieu, France 18.Apr Draft IERC AC4 meeting at EW 2013, Guilford, UK 15.May Draft External Liaison Projects 18.Jun Draft Release at IoTWeek 2013, Helsinki, Finland For comments / contributions 10.Jul Draft Data Collection contributions: Section 3.2 Update 25.Jul Draft Data Formalism and Languages in IoT: section 3.4 Update 10.Aug Draft Editors Conference Call Review on Additional Project Contributions 25.Aug Draft Final Edits / Contributions 30.Aug.2013 V.1 Final V1 Released / Circulated 1

8 Manifiesto-V1 TABLE OF CONTENTS Foreword Scope Audience Summary Structure Introduction Semantics and Interoperability Semantics and technology Semantic for interoperability Semantics why, where, how? Vocabulary and Terminology Data Model Information Model Data exchange Knowledge representation Knowledge sharing Mapping Matching and Alignment Concepts Representation Relationships Functions Instances Axioms Ontology Objects vs. Things Interoperability by Ontologies Methodologies & Tools for Data in IoT Taxonomy and Structure of the Information By its persistence:

9 Manifiesto-V By its medium: By its relevance to the service: By its temporal characteristics: By its temporal situation: Capturing the information (how information is acquired in IoT) Observation, Measurement and Actuation Resource Description Entity Description Data Publishing and consumption Publishing Consuming Data Formalisms and Languages in IoT Semantic web technologies Other alternatives Tools for Developments & Implementations in IoT Software project management tool Apache Maven Development Environment Eclipse IDE Web-Service implementation Apache CXF User Interfaces Web Clients Fat Clients Platform Management Java Management Extensions (JMX) Enterprise Application Platform JBoss Application Platform Knowledge Database RDF Database JENA Sesame Virtuoso Ontologies Sensor Domain Semantic Sensor Network Ontology (SSN)

10 Manifiesto-V Social Communities Domain Semantically-Interlinked Online Communities (SIOC) Friend Of A Friend Ontology (FOAF) Provenance Ontology (PROV) Association Ontology (AO) Context Information Modeling Domain Event Model-F Ontology (Event)) SPITFIRE Ontology (SPT) Network Components Domain SPITFIRE Ontology (SPT) Energy Domain SPITFIRE Ontology (SPT) Cloud Computing Domain IT Services Ontology (ITSO) Cloud4SOA Project UCI Project MOSAIC Project Scenarios / Use cases Smart City Student Campus Application Application Description External Interfaces Requirements Application Functionalities and Functional Requirements Non-Functional Requirements Phenonet Agriculture Application Application Description Application Functionalities and Functional Requirements Onsite sensor diagnostic tool (e.g., Android application on tablets) Domain-specific Analysis and Visualisations Non-Functional Requirements Licencing Requirements Manufacturing Application Application Description Manufacturing Environment Application Scenarios Application Functionalities and Functional Requirements Main Functionalities

11 Manifiesto-V Sensors and Internet-Connected Objects Involved Utility to be Measured List of Functional Requirements External Interfaces Requirements Non-Functional Requirements Other Requirements Other End-user Applications Applications from other IERC projects ebbits IoT-A ELLIOT NEFFICS ( FP7 Projects interested/related with semantics icore-internet Connected Objects for Reconfigurable Eco-System A brief description of the project Interoperability related issues (focus on semantics) Semantic Interoperability of VOs/CVOs icore vision in terms of Semantic Interoperability Current approach IoT@Work (Internet of Things at Work) A brief description of the project Interoperability related issues (Semantics) Current approach Internet of Things Environment for Service Creation and Testing (IoT.est) A brief description of the project (Short Abstract) Interoperability related issues (Semantics) Current approach (Advances, Development, Solutions, etc.) Generic Adaptive Middleware for Behavior-driven Autonomous Services (GAMBAS) A brief description of the project (Short Abstract) Interoperability related issues (Semantics) Current approach (Advances, Development, Solutions, etc.) ubiquitous, secure internet-of-things with Location and contex-awareness (BUTLER) A brief description of the project (Short Abstract) Interoperability related issues (Semantics) Current approach (Advances, Development, Solutions, etc.)

12 Manifiesto-V1 6.6 Enterprise Collaboration & Interoperability (COIN) A brief description of the project (Short Abstract) Interoperability related issues (Semantics) Current approach (Advances, Development, Solutions, etc.) Open source blueprint for large scale self-organizing cloud environments for IoT applications (OpenIoT) A brief description of the project (Short Abstract) Interoperability related issues (Semantics) Universal Integration of the Internet of Things through an IPv6-based Service Oriented Architecture enabling heterogeneous components interoperability (IoT6) A brief description of the project (Short Abstract) Interoperability related issues (Semantics) Current approach (Advances, Development, Solutions, etc.) SmartAgriFood (FI PPP Grant no ) A brief description of the project (Short Abstract) Interoperability related issues (Semantics) Current approach (Advances, Development, Solutions, etc.) Emergent Connectors for Eternal Software Intensive Networked Systems CONNECT A brief description of the project (Short Abstract) Interoperability related issues (Semantics) Current approach (Advances, Development, Solutions, etc.) Large Scale Choreographies for the Future Internet CHOReOS A brief description of the project (Short Abstract) Interoperability related issues (Semantics) Current approach (Advances, Development, Solutions, etc.) Collaborative Manufacturing Network for Competitive Advantage ComVantage A brief description of the project (Short Abstract) Interoperability related issues (Semantics) Current approach (Advances, Development, Solutions, etc.) External Liaison Projects Project Title: Interoperable Sensor Networks (09034 ISN) A brief description of the project (Short Abstract) Interoperability related issues (Semantics) Current approach (Advances, Development, Solutions, etc.)

13 Manifiesto-V1 8 IoT Initiatives Council, a think-tank for the Internet of Things (UK) A brief description of the project (Short Abstract) Interoperability related issues (Semantics) Current approach (Advances, Development, Solutions, etc.) Researches of architecture and key technologies of WEB based wireless ubiquitous service environment, and proof-of-concept & demonstration (China) A brief description of the project (Short Abstract) Interoperability related issues (Semantics) Current approach (Advances, Development, Solutions, etc.) COMUS - Common Open semantic Usn Service Platform (Korea) A brief description of the project (Short Abstract) Interoperability related issues (Semantics) Current approach (Advances, Development, Solutions, etc.) Future Actions / Activities Semantic technologies and IoT resource description frameworks Practical modelling and ontology engineering Interoperability evaluation Interfaces and communications The software and tools requirements Conclusions References Annex I: Other Useful References

14 Manifiesto-V1 LIST OF FIGURES FIGURE 1. THE DIMENSIONS OF INTEROPERABILITY FIGURE 2. SEMANTIC WEB TECHNOLOGIES FIGURE 3. INFORMATION MODELS ONTOLOGY ENGINEERING FIGURE 4. KIT CAMPUS AREA FIGURE 5. KITCAMPUSGUIDE AS AN HERO APPLICATION FIGURE 6. PICTURE: IOT EQUIPPED WORKPLACE FIGURE 7. ENHANCEMENT OF THE KCG WORKPLACE SEARCH WITH IOT TECHNOLOGY FIGURE 8. MAIN DATA SOURCES FOR CROP PERFORMANCE MONITORING IN THE SCOPE OF THE PHENONET PROJECT FIGURE 9. ILLUSTRATION OF LICENCING REQUIREMENTS ASSOCIATED WITH THE (RE)USE OF PHENONET IN THE SCOPE OF OPENIOT FIGURE 10. IMAGE SENSOR TO BE USED IN THE MANUFACTURING SCENARIOS FIGURE 11. OPTICAL DIFFUSION SENSOR TO BE USED IN THE MANUFACTURING SCENARIOS FIGURE 12. LASER BARCODE SCANNER (ULTRA HIGH SPEED) TO BE USED IN THE MANUFACTURING SCENARIOS (FOR PROOF OF DELIVERY) FIGURE 13. SMART PROXY ARCHITECTURE FIGURE 14. THE GAMBAS APPROACH FIGURE 15. THE OPENIOT APPROACH FIGURE 16. REFERENCE ARCHITECTURE FOR DATA- AND PROCESS-INTEROPERABILITY IN A VIRTUAL ENTERPRISE FIGURE 17. WOT SYSTEM ARCHITECTURE IN THE PROJECT FIGURE 18. ITU-T F.OPENUSN (DRAFT) FIGURE 19. RESOURCE ONTOLOGY GRAPH REPRESENTATION FIGURE 20. DOMAIN ONTOLOGY MAPPING REPRESENTATION FIGURE 21. LINKED OPEN DATA LOUD REPRESENTATION FOR SENSOR SERVICES FIGURE 22. THE ECONOMIC DIMENSION IN THE INTERNET OF THINGS LIST OF TABLES TABLE 1: IOT TECHNICAL INTEROPERABILITY CHALLENGES/REQUIREMENTS TABLE 2: IOT SEMANTIC INTEROPERABILITY CHALLENGES/REQUIREMENTS

15 Manifiesto-V1 TERMS AND ACRONYMS 6LoWPAN AAL ARM BPM BPMN BPWME CoAP CPI CRUD DOLCE DoW DSO EPC EPC-ALE EPC-IS ERP GPL GPS GSN GTIN HTML HTTP JSF ICO ICT IEEE IETF IERC IoT LGPL MRP OGC IPv6 over Low power Wireless Personal Area Networks Ambient Assisted Living Architecture Reference Model Business Process Language Business Process Modelling Notation Business Process Workflow Management Editor Constrained Application Protocol CSIRO Plant Industry CReate, Updated, Delete Descriptive Ontology for Linguistic and Cognitive Engineering Description-of-Work Decision Support Ontology Electronic Product Code Electronic Product Code Application Level Events Electronic Product Code Information Sharing Enterprise Resource Planning General Public Licence Global Positioning System Global Sensor Networks Global Trade Item Number HyperText Markup Language Hypertext Transfer Protocol Java Server Faces Internet-Connected Objects Information and Communication Technologies Institute of Electrical and Electronics Engineers Internet Engineering Task Force Research Cluster for the Internet of Things Internet of Things Lesser General Public License Manufacturing Resource Planning Open Geospatial Consortium 9

16 Manifiesto-V1 OMG ONS PDA PET QoS QR-Code RDF REST RFID SGTIN SLA SME SOA SOS SPS SSN UML WSN XML Object Management Group Object Naming Service Personal Digital Assistant Privacy Enhancing Technologies Quality of Service Quick Response Code Resource Description Format Representational State Transfer Radio Frequency Identification Serialized Global Identification Number Service Level Agreement Small Medium Enterprise Service Oriented Architecture Sensor Observation Service Sensor Planning Service Semantic Sensor Networks Unified Modelling Language Wireless Sensor Networks extensible Markup Language 10

17 Manifiesto-V1 Foreword The design of the Internet and telecommunication systems relies on the convergence of Software Engineering and Technology (infrastructure). Every day it is a common practice to think/design cross solutions between software and infrastructure in order to provide integrated solutions for some of the complex problems in the current and future Internet systems. In Information Technologies and Communications (ITC) systems this convergence is evident, however the conceptual realization is far from achieving a full deployment of converged services and technology. Current ITC research is focused on the integrated solutions and primarily on the feature that enable convergence named as Interoperability. Interoperability can be generalized as the feature for providing seamless exchange of information to, for example, personalize services automatically or simply exchange information that other systems can use for improving performance, enable and create services, control operations and information processing. This type of scenarios requires increased interoperability in service management operations. Scope In this document we review recent trends and challenges on interoperability, discuss physical versus virtual and while addressing technology interoperability challenges in parallel, discuss how, with the growing importance of data understanding and processing, semantic web and their technologies, frameworks and information models can support data interoperability in the design of the Future Internet. Internet of Things (IoT) is taken as reference example in enterprise applications and services and their importance of the economic dimension. Audience This document addresses the following audiences: Researchers and engineers within the IERC-AC4 community, which will take into account the various requirements in order to research, design and implement the architecture of the OpenIoT platform. Researchers on IoT systems at large, given that the present deliverable could be a useful reading for researchers studying alternative IoT technologies and applications, along with indications and requirements towards building/establishing AIT architectures. Members of other Internet-of-Things (IoT) projects (such as projects of the IERC cluster), which can find in this document a readily available requirements analysis for utility-based IoT applications. For these projects the document could provide insights into requirements and technological building blocks enabling the convergence between utility/cloud computing and the Internet-of-Things. 11

18 Manifiesto-V1 Summary Internet of Things (IoT) is an emerging area that not only requires development of infrastructure and software Engineering development but also the design and deployment of new services capable of supporting multiple, scalable and interoperable (multi-domain) applications. In the race of designing the IoT as part of the Future Internet architecture, academic and ICT s (Information and Communication Technology) industry communities have realized that a common IoT problem to be tackled is the interoperability of the information. In this document we review and summarize recent trends and challenges on interoperability, and discuss how semantic technologies, open service frameworks and information models can support data interoperability in the design of the Future Internet, taking the IoT and Cloud Computing as reference examples of application domains. In addition this document compile the European and world-wide initiatives for the Internet of things in the framework of the IERC (European Research Cluster for the Internet of Things) and particularly the Activity Cluster on Service Openness and Inter-operability Issues/Semantic Interoperability (AC4) Structure This IERC-AC4 document/deliverable is structured as follows: Section 1 contains this introductory section with references aiming for common understanding about service openness and interoperability, traditional interoperability is explained and two additional dimensions proposed and discussed. Section 2 describes important terminology for the Internet of Things domain aligned with (ontology engineering) semantics. Section 3 analyses the overall methodologies to classify, consume and publish data. Section 4 introduces most useful tools in the Internet of Things for enabling interoperability, while this list is preliminary and can be extended, it aim for including the most common tools used amongst the IERC EU FP7 projects related with Semantic interoperability. Section 5 identifies key scenarios/use cases for the Internet of Things, while the diversity of use cases for the Internet of Things applications is wide, in this document three distinct use cases in the areas of e-science, smart cities and manufacturing highlight are explained in fair detail. These scenarios / use cases can be considered as generalization in the area. Section 6 organize the EU FP7 interested/related with semantics, the objective is to joint activities by the entire IERC AC4 project participants, which will support and facilitate individual exploitation about the technologies and solutions developed and establish the first linkage between the IERC project member participants and at the same time promote collaboration. Section 8 includes those external to IERC / FP7 programs in the area of Internet of Things and with close relation to Semantics and service openness. Section 9 goes beyond the boundaries of Europe and includes those world initiatives in the area of Internet of Things or similar. Section 9 draws conclusions about key factors that the design of the Internet of Things must address in terms of semantic interoperability in order to meet business requirements. Finally the references and other useful references are included. 12

19 Manifiesto-V1 1 Introduction Internet of Things (IoT) is an emerging area that not only requires development of infrastructure but also deployment of new services capable of supporting multiple, scalable (cloudbased) and interoperable (multi-domain) applications. In the race of designing the IoT as part of the Future Internet architecture, academic and ICT s (Information and Communication Technology) industry communities have realized that a common IoT problem to be tackled is the interoperability of the information. In this paper we review recent trends and challenges on interoperability, and discuss how semantic technologies, open service frameworks and information models can support data interoperability in the design of the Future Internet, taking the IoT and Cloud Computing as reference examples of application domains. Extensible discussed the Internet of Things (IoT) refers to things ( objects ) and the virtual representations of these objects on the Internet. IoT defines how the things will be connected through the Internet and how those things talk amongst other things and communicate with other systems in order to expose their capabilities and functionalities services. Internet of Things is not only linking connected electronic devices by using the Internet; it is also web-enabled data exchange in order to enable systems with more capacities smartness. In other words IoT aims for integrating the physical world with the virtual world by using the Internet as the medium to communicate and exchange information. Technically speaking IoT is mainly supported by continuous progress in wireless sensor networks software applications and by manufacturing low cost and energy efficient hardware for sensor and device communications. However, heterogeneity of underlying devices and communication technologies and interoperability in different layers, from communication and seamless integration of devices to interoperability of data generated by the IoT resources, is a challenge for expanding generic IoT solutions to a global scale. In this article we present various parallel and inter-related interoperability challenges ensuring that technologies deliver information in a seamless manner while this information is understood whatever the context and efficiently processed to deliver the potential of innovative services we are looking for. To make everything simpler in our life tomorrow in using any object, any information, anywhere we need to solve complex interoperability issues today. 1.1 Semantics and Interoperability First we need to understand interoperability. The main objective of this article is not to produce a new definition on interoperability but explore the different roles and functionality interoperability plays in the Internet of Things today. In this sense there are many definitions of interoperability but for instance in the context of the 3rd Generation Partnership Project, 3GPP, interoperability is: "the ability of two or more systems or components to exchange data and use information" 13

20 Manifiesto-V1 This definition is interesting as provide many challenges on how to: Get the information, Exchange data, and Use the information in understanding it and being able to process it. A simple representation of interoperability can be seen as follow: Syntactical Interoperability Technical Interoperability Semantic Interoperability Organisational Interoperability Figure 1. The Dimensions of Interoperability In a white paper on interoperability [vanderveer 2008], we can get the following definition(s): Technical Interoperability is usually associated with hardware/software components, systems and platforms that enable machine-to-machine communication to take place. This kind of interoperability is often centred on (communication) protocols and the infrastructure needed for those protocols to operate. Syntactical Interoperability is usually associated with data formats. Certainly, the messages transferred by communication protocols need to have a well-defined syntax and encoding, even if it is only in the form of bit-tables. However, many protocols carry data or content, and this can be represented using high-level transfer syntaxes such as HTML, XML or ASN.1 Semantic Interoperability is usually associated with the meaning of content and concerns the human rather than machine interpretation of the content. Thus, interoperability on this level means that there is a common understanding between people of the meaning of the content (information) being exchanged. Organizational Interoperability, as the name implies, is the ability of organizations to effectively communicate and transfer (meaningful) data (information) even though they may be using a variety of different information systems over widely different infrastructures, possibly across different geographic regions and cultures. Organizational interoperability depends on successful technical, syntactical and semantic interoperability. 14

21 Manifiesto-V1 We can add two other dimensions: Static and dynamic interoperability We should not also forget that two products couldn t interoperate if they don t implement the same set of options. Therefore when specifications are including a broad range of options, this aspect could lead to serious interoperability problem. Solutions to overcome these aspects consist of definition clearly in a clear document the full list options with all conditions (e.g. defined as PICS in [ISO 9646]) as well as to define set of profiles. In the later case, defining profile would help to truly check interoperability between two products in the same family or from different family if the feature checked belong to the two groups. We could consider this aspect as static interoperability using approach of the well-known OSI overall test methodology ISO 9646 [ISO9646], where there is definition of static conformance review. Conformance testing consists of checking whether an IUT (Implementation Under Test) satisfies all static and dynamic conformance requirements. For the static conformance requirements this means a re- viewing process of the options (PICS) delivered with the IUT. This is referred to as the static conformance review. This aspect could appear easy but that represent serious challenge in the IoT field due the broad range of applications. In the meantime, in front of growing complexity we also noticed many solutions to adapt to non-interoperability leading to be able to communicate and understand. One interesting research as presented by eternal interoperability here in one of the section below consists to accept differences and potential non-interoperability for instance between two different protocols but to adapt on the fly. We see also such features in intelligent gateways and middlewares. This can be called dynamic interoperability and should be a continuous important research area in particular with the growing complexity and heterogeneity of IoT environments Semantics and technology IoT environments for Internet-connected objects will greatly facilitate the deployment and delivery of applications, since they will enable businesses and citizens to select appropriate data and service providers rather than having to deploy physical devices commonly called sensors. At the same time, they will provide capabilities (such as on-demand large scale sensing), beyond what is nowadays possible. It is important to highlight the origins of IoT are found in the area of (Radio Frequency IDentification) RFID domain where RFID tags are extensively used for data collection. The static information a group of RFID tags can generate motivated the quick development of RFID middleware frameworks to the extent that nowadays FID frameworks provides functionality for RFID data collection, filtering, event generation, as well as translation of tag streams into business semantics. Several initiatives have produced several open-source RFID frameworks, such as Mobitec [MOBITEC], AspireRFID [ASPIRE] as well as the fosstrak project [FOSSTRAK] which provide royalty-free implementations of RFID middleware stacks. The evolution has 15

22 Manifiesto-V1 continued and the generators of data are now generally named sensors by their capacity to produce data and their flexibility to create cells or groups of them by using embedded wireless technology. In this sense several middleware platforms have also been devised in the area of WSN (Wireless Sensor Networks). Specifically, there are platforms addressing only the level of the sensor network, whereas other deal also with devices and networks connected to the WSN. Some middleware platforms are characterized as sensor databases, other as virtual machines, whereas there are also publish-subscribe approaches. Systems such as Moteview [BULLSEYE] and ScatterViewer [SCATTERVIEWER] are examples of WSN development and monitoring systems, which however provide limited extensibility (tightly coupled approach). Other environments such as Hourglass [HOURGLASS], SenseWeb [SENSEWEB], jwebdust [JWEBDUST] and GSN [GSN] provide more complete development and/or programming environments for WSN applications. Beyond the limits of physical devices known as sensors there is also a notion of Virtual Sensor that refers to a core representation of an element of the IoT platforms representing new data sources created from live data. These virtual sensors can filter, aggregate or transform the data. From an end-user perspective, both virtual and physical sensors are very closely related concepts since they both, simply speaking, measured data. The Semantic Sensor Network (SSN) ontology, providing the most important core vocabulary for sensing data, defines the notion of sensor and physical devices in general, therefore formally the concept of a virtual sensor as a subclass of the sensor concept as defined in the SSN ontology. Due to the rising popularity of IoT technologies and applications the emergence of a wide range of platforms that enable users to build and/or use IoT applications is unavoidable. In general there is a clear trend towards the convergence of physical worlds and virtual solutions by using IoT technologies. In all cases either Physical or Virtual sensors, a middleware framework is the core element to be used for providing baseline sensor functionalities associated with registering and looking up internet-connected objects, exchanging messages between objects, as well as fusing and reasoning data from multiple-objects. Some features of these implementations are: 0 integrate ontologies and semantic structures, in order to enable semantic interactions and interoperability between the various objects, which will be a significant advancement over the existing syntactic interactions. 1 provide Open Linked Data interfaces (e.g., SPARQL (SPARQL Protocol and RDF Query Language) over ontologies for internet-connected objects within the physical world middleware to interact with virtual world). 2 Define techniques for the automated data configuration of filtering, fusion and reasoning mechanisms, according to the problems/tasks at hand Semantic for interoperability The overall challenges in interoperability is first to stabilize the foundation of the real world, ensuring technical interoperability from technologies to deliver mass of information and then complementary challenges are for the information to be understood and processed. Before entering into details we will in the tables below present a summary of the challenges for technical and semantic interoperability. 16

23 Manifiesto-V1 Table 1: IoT Technical Interoperability Challenges/Requirements Requirement(s) Best practices awareness Avoid spreading effort in addressing interoperability for worldwide protocols Validation of specifications Reduce ambiguities in specifications and development time Rationale & Remarks Coordinate worldwide interoperability initiatives on market support specifications or protocols Develop market acceptance roadmap Use clear specifications development and testing methodologies leading to improve quality while reducing time and costs in a full chain optimized development cycle Define if needed profiles to improve interoperability Specifications development time could be too long Ambiguities in specifications could lead to major non interoperability issues Quality, time and cost factors lead to the needs of models and automation Tests specifications Provide market accepted test specifications ensuring minimum accepted level of interoperability No test specifications lead inevitably to different specifications implementation and interoperability issues Development test specifications is often too expensive for limited set of stake holders and effort should be collectively shared Tools processing and automation are only way to reduce time and market (e.g. use of MBT) Tools and validation programmes Develop market accepted and affordable test tools used in market accepted validation programs Development of test tools are expensive Available test tools developed spontaneously by market forces can have test scopes overlapping and even not answering to all tests needs. Full chain of specifications to tool development not considered Providing final confidence to end users with consistent tests not always considered The following table/ lists summarize the main requirements associated with the development of the IoT service(s) / application(s) in reference to semantic interoperability requirements and moreover, it provides the main rationale that has led to these requirements. 17

24 Manifiesto-V1 Table 2: IoT Semantic Interoperability Challenges/Requirements Requirement(s) Integration Support multiple ICOs (sensors, actuators) and relevant types of data sources (independently of vendor and ICO location). Rationale & Remarks Enable scalable sharing and integration of distributed data sources. All IoT applications involve multiple heterogeneous devices. Orchestrate ICOs in order to automatically formulate composite workflows as required by end-user applications. Annotation Enable the (automated) linking of relevant data sources. Linking of data sources facilitates application integration and reuse of data. Enable interactions between ICOs and between IoT services. Built on the standards i(.e. W3C SSN standard ontology) for description of sensors and ICOs. Management Enable the creation and management of virtual sensors and virtual ICOs based on the composition and fusion of streams stemming from multiple (ICO) data sources. Application development and integration involves multiple distributed and heterogeneous data sources to be processed in parallel. The definition and management of virtual sensors eases applications integration. Discovery Provide the means for discovering and selecting ICOs and data sources pertaining to application requests (according to their capabilities). Analysis and Reasoning Provide analytical and reasoning tools on top of semantic level capabilities. End users need a high-level interface to be accessed. Provide the means for describing/formulating IoT services and applications according to high-level descriptions. Provide (configurable) visualisation capabilities of multiple integrated data sources (in a mashup fashion). IoT addresses large-scale environments with numerous ICOs featuring different functionalities and capabilities. End-user applications involve the monitoring of virtual and/or Physical sensors Visualisation Optimise usage of resources (storage, computing cycle, sensor utilisation) across multiple users sharing these resources. Several applications involve object-to-object (e.g., M2M) interactions or interactions between services; such interactions could be either defined explicitly (i.e. by end users) or derive implicitly (based on the application context). 18

25 Manifiesto-V1 1.2 Semantics why, where, how? Taking a broad view of state of the art and current development of interactions for interoperability in converging communications, many of the problems present in current Internet will remain in the Internet of Things systems and mainly generated by interoperability problems, thus there are three persistent problems: 1. Users are offered relatively small numbers of Internet services, which they cannot personalise to meet their evolving needs; communities of users cannot tailor services to help create, improve and sustain their social interactions; 2. The Internet services that are offered are typically technology-driven and static, designed to maximise usage of capabilities of underlying network technologies and not to satisfy user requirements per se, and thus cannot be readily adapted to their changing operational context; 3. Network operators cannot configure their networks to operate effectively in the face of changing service usage patterns and rapid networking technology deployment; networks can only be optimised, on an individual basis, to meet specific low-level objectives, often resulting in sub-optimal operation in comparison to the more important business and service user objectives. As the move towards Internet of Things, the convergence of communications and a more extended service-oriented architecture (SOA) design gains momentum, worldwide there is an increasingly focussing on how to evolve communications technologies to enable the Internet of Things. The aim is directed mainly by pervasive deployment of Internet protocol suites and VoIP is a clear example of this... In this sense we believe that addressing evolution of networking technologies in isolation is not enough; instead, it is necessary to take a multidomain adaptable holistic view of the evolution of communications services, their societal drivers and the requirements they will place on the heterogeneous communications infrastructure over which they are delivered. By addressing information interoperability challenge issues, Internet of Things systems must be able to exchange information and customize their services. So Future Internet can reflect changing individual and societal preferences in network and services and can be effectively managed to ensure delivery of critical services in a services-aware design view with general infrastructure challenges. Figure 2 courtesy of chain-reds project. Figure 2. Semantic Web technologies 19

26 Manifiesto-V1 2 Vocabulary and Terminology 2.1 Data Model One of the most difficult aspects in the Internet of Things is the dynamism of the data. Changes in the data must be detected in real time, and the applications must quickly adapt to such changes [Dey01]. The nature of the information is the most important feature to consider when data is being handled, IoT systems needs data to process instructions and generate outcomes; if IoT applications can fully exploit the richness of de data, services around data management will be dramatically simplified [Brown98]. Other important challenges in the Internet of Things in relation with data include: (1) how to represent and standardize the data, (2) if the data is correctly collected (trust and validity) and represented, and (3) if the information can be translated to a standard format (information model), then different applications can all use the information. Finally, some types of data also depend on user interfaces (which can make retrieving data much easier), or the type of technologies used to generate the information. 2.2 Information Model Modelling data is one of the major challenges in the Internet of Things services deployment, without having a defined, clear and at same time flexible information model, applications will not be able to use such information in an efficient way for taking advantage of all of the benefits that the context information can provide for the service as well as for the provisioning of that service. The information model must be rich and flexible enough to accommodate not only the current facets of information, but also future ones [Dey01]. It has to be based on standards as much as possible and moreover, the model should scale well with respect to the associated technology and the applications. This introduces a great challenge for managing this information in a consistent and coherent manner. Storage and retrieval of this information is also important. Another important aspect to consider in the information model is the continuous evolution in technology and the Internet of Things services offering towards mobility. This mobility demand the integration of information in heterogeneous, distributed technologies and systems. By adding descriptions to the data, the transformation to valuable Information plays an important role in next generation Internet and IoT systems which. Since the incorporation of the mobility concept and recently, each day more popular, cloud computing systems the information require the development of extensible context models that enable the efficient representation for handling and distribution of the information in the information systems 20

27 Manifiesto-V1 2.3 Data exchange The model in the Internet of Things for exchanging data is based on simple concepts and its relationships, as syntactical descriptions, between those concepts, for example an object or entity is composed of a set of intrinsic characteristics or attributes that define the entity itself, plus a set of relationships with other entities that partially describe how it interacts with those entities. The objects/entities can represent anything that is relevant to the management domain [Chen76] (in this case IoT). Moreover, the relations that can exist between the different model entities can represent many different types of influence, dependence, links and so on, depending mainly on the type of entities that these relationships connect. The model s objective is to describe the entity and its interaction with other entities by describing the data and relationships that are used in as much detail as is required. This abstraction enables the model to be made more comprehensible by different applications. Since this format is machine-readable, the information can be processed by applications much easier than an equivalent, free-form textual description. 2.4 Knowledge representation In the Internet of Things the knowledge modelling depends on the point of view of the application definition and scope. The information model is a first approximation on how to structure, express and organize the information [Dey00a][Dey01] the knowledge representation is the information associated to the service. The information model is based on the concepts of entity and relationship and derived from the definition of entity in [Chen76] the knowledge model is derived from the service or application. The concept of the local context of an entity can be defined as the information that characterizes the status of the entity. This status is made up of its attributes and its relationships. Moreover, the relationships that can exist between the different entities inside the model, as well as the entities themselves, can represent many different types of influences, dependencies, and so on, depending on the type of entities that these relationships connect. With this type of model, one can construct a net of entities and relationships representing the world surrounding the activity of a context-aware service and thus the models can influence the development of the activity or service. This enables a scenario made up of many different types of information, and the influences or nexus that links one with the others. The local context enables the service to select and use context information from this scenario that is considered relevant in order to perform its task and deploy its service. 2.5 Knowledge sharing The tools that could be used to represent and implement data model, and the way to integrate this information model inside the general IoT system architecture, need to be identified and tested, as they are potential tools for representing the context information. RDF is a flexible and platform-independent tool that can be used in different stages of the information representation, which makes implementation consistent and much easier. The use of RDF is increasing every day; however, it is by definition generic. Therefore, new languages that are based on RDF have been developed that add application-specific features as part of the language definition. For example, to customize services, languages must have concepts that are related to the operational mechanisms of that service. 21