Intelligent context-aware services based on internet of things architectures

Texto completo

(1)UNIVERSIDAD POLITÉCNICA DE MADRID. ESCUELA TÉCNICA SUPERIOR DE INGENIEROS DE TELECOMUNICACIÓN. . Intelligent Context-Aware Services based on Internet of Things Architectures . TESIS DOCTORAL . JESUS BERNAT VERCHER Licenciado en Informática. 2012. .

(2) . .

(3) DEPARTAMENTO DE SEÑALES, SISTEMAS Y RADIOCOMUNICACIONES ESCUELA TÉCNICA SUPERIOR DE INGENIEROS DE TELECOMUNICACIÓN. . Intelligent Context-Aware Services based on Internet of Things Architectures . AUTOR:. JESÚS BERNAT VERCHER Licenciado en Informática. DIRECTOR:. LUIS A. HERNÁNDEZ GÓMEZ Doctor Ingeniero de Telecomunicación. Madrid, 2012. .

(4) . .

(5) . . . .

(6) . .

(7) A Maite, Miriam y Pilar… . .

(8)

(9) . Agradecimientos Esta Tesis es el resultado de varios años de investigación que se ha ido realizando al amparo de muchos proyectos de colaboración como el SmartSantander, SENSEI e IoT-‐A, todos ellos pertenecientes al Séptimo programa marco (FP7) de la UE, además de actividades internas de Telefónica. Mucha gente ha participado de forma más o menos directa y más o menos consciente. Gracias a todos ellos. Primero que todo es de justicia y un placer agradecer a mi director de Tesis, Luís, la paciencia, insistencia, dedicación, ánimos, consejos, colaboración, … y sobre todo humanidad. Sin ellos no hubiera sido posible ni siquiera empezarla. “Gracias por todos estos años que hemos estado trabajando juntos y espero que podamos continuar por muchos años más”. A toda mi familia. Especialmente a mi mujer, Maite, y a mis hijas, Miriam y Pilar, no sólo por la comprensión y el apoyo que siempre han tenido para con mi investigación, sino por la cantidad enorme de tiempo que han tenido que prescindir de mi como marido y padre. ¡¡¡Gracias!!!! También agradecerles a mis padres no sólo la insistencia en que la acabara, sino el empeño que siempre han puesto en inculcarme los valores del esfuerzo y constancia sin los cuales hubiera sido imposible realizarla. A mis compañeros de trabajo en Telefónica I+D. Ha habido muchos durante estos años, pero quisiera hacer mención especial a José Manuel, Agustín, Fernando, Alfonso, Rafa, Eva, Demetrio, David, Luís y los muchos que me dejo en el tintero. Ellos son posiblemente casi tan responsables como yo de buena parte de los resultados de esta Tesis. También quiero agradecer a toda la buena gente con la que he participado en los distintos proyectos de investigación en los que he estado: Luis, Verónica, José Antonio, Luis, Alex, Martin, Mathias, Payam, Martin, Claudia, Vlasios, Srdjan, Fred, Mirko, Tomás, Vlad, etc. Gracias por las charlas, discusiones y tertulias que han ayudado a madurar las ideas presentadas en este trabajo. Gracias al grupo de gente que conmigo ha participado en la definición del estándar M2M de la ETSI: Enrico, Susana, Josef, Jurgen, Omar, Michele, Patricia, Marylin, Barbara, Erik, George, etc. Ellos no sólo me han hecho comprender la visión pragmática de las comunicaciones M2M, sino que me han hecho entender y respetar el complejo mundo de la estandarización. Finalmente, gracias a mis compañeros del SSR (José Luís, los dos Álvaros, David, Rubén, Bea, etc.), que, a pesar de verme poco el pelo por allí, siempre han estado prestos a echarme una mano y colaborar cuando se lo he pedido. ¡A todos gracias! . i .

(10)

(11) Resumen La Internet de las Cosas (IoT), como parte de la Futura Internet, se ha convertido en la actualidad en uno de los principales temas de investigación; en parte gracias a la atención que la sociedad está poniendo en el desarrollo de determinado tipo de servicios (telemetría, generación inteligente de energía, telesanidad, etc.) y por las recientes previsiones económicas que sitúan a algunos actores, como los operadores de telecomunicaciones (que se encuentran desesperadamente buscando nuevas oportunidades), al frente empujando algunas tecnologías interrelacionadas como las comunicaciones Máquina a Máquina (M2M). En este contexto, un importante número de actividades de investigación a nivel mundial se están realizando en distintas facetas: comunicaciones de redes de sensores, procesado de información, almacenamiento de grandes cantidades de datos (big-‐data), semántica, arquitecturas de servicio, etc. Todas ellas, de forma independiente, están llegando a un nivel de madurez que permiten vislumbrar la realización de la Internet de las Cosas más que como un sueño, como una realidad tangible. Sin embargo, los servicios anteriormente mencionados no pueden esperar a desarrollarse hasta que las actividades de investigación obtengan soluciones holísticas completas. Es importante proporcionar resultados intermedios que eviten soluciones verticales realizadas para desarrollos particulares. En este trabajo, nos hemos focalizado en la creación de una plataforma de servicios que pretende facilitar, por una parte la integración de redes de sensores y actuadores heterogéneas y geográficamente distribuidas, y por otra lado el desarrollo de servicios horizontales utilizando dichas redes y la información que proporcionan. Este habilitador se utilizará para el desarrollo de servicios y para la experimentación en la Internet de las Cosas. Previo a la definición de la plataforma, se ha realizado un importante estudio focalizando no sólo trabajos y proyectos de investigación, sino también actividades de estandarización. Los resultados se pueden resumir en las siguientes aseveraciones: a) Los modelos de datos definidos por el grupo “Sensor Web Enablement” (SWE™) del “Open Geospatial Consortium (OGC®)” representan hoy en día la solución más completa para describir las redes de sensores y actuadores así como las observaciones. b) Las interfaces OGC, a pesar de las limitaciones que requieren cambios y extensiones, podrían ser utilizadas como las bases para acceder a sensores y datos. c) Las redes de nueva generación (NGN) ofrecen un buen sustrato que facilita la integración de redes de sensores y el desarrollo de servicios. En consecuencia, una nueva plataforma de Servicios, llamada Ubiquitous Sensor Networks (USN), se ha definido en esta Tesis tratando de contribuir a rellenar los huecos previamente mencionados. Los puntos más destacados de la plataforma USN son: a) Desde un punto de vista arquitectónico, sigue una aproximación de dos niveles (Habilitador y Gateway) similar a otros habilitadores que utilizan las NGN (como el OMA Presence). b) Los modelos de datos están basado en los estándares del OGC SWE. . iii .

(12) c) Está integrado en las NGN pero puede ser utilizado sin ellas utilizando infraestructuras IP abiertas. d) Las principales funciones son: Descubrimiento de sensores, Almacenamiento de observaciones, Publicación-‐subscripción-‐notificación, ejecución remota homogénea, seguridad, gestión de diccionarios de datos, facilidades de monitorización, utilidades de conversión de protocolos, interacciones síncronas y asíncronas, soporte para el “streaming” y arbitrado básico de recursos. Para demostrar las funcionalidades que la Plataforma USN propuesta pueden ofrecer a los futuros escenarios de la Internet de las Cosas, se presentan resultados experimentales de tres pruebas de concepto (telemetría, “Smart Places” y monitorización medioambiental) reales a pequeña escala y un estudio sobre semántica (sistema de información vehicular). Además, se está utilizando actualmente como Habilitador para desarrollar tanto experimentación como servicios reales en el proyecto Europeo SmartSantander (que aspira a integrar alrededor de 20.000 dispositivos IoT). . . . iv .

(13) Abstract Internet of Things, as part of the Future Internet, has become one of the main research topics nowadays; in part thanks to the pressure the society is putting on the development of a particular kind of services (Smart metering, Smart Grids, eHealth, etc.), and by the recent business forecasts that situate some players, like Telecom Operators (which are desperately seeking for new opportunities), at the forefront pushing for some interrelated technologies like Machine-‐to-‐Machine (M2M) communications. Under this context, an important number of research activities are currently taking place worldwide at different levels: sensor network communications, information processing, big-‐ data storage, semantics, service level architectures, etc. All of them, isolated, are arriving to a level of maturity that envision the achievement of Internet of Things (IoT) more than a dream, a tangible goal. However, the aforementioned services cannot wait to be developed until the holistic research actions bring complete solutions. It is important to come out with intermediate results that avoid vertical solutions tailored for particular deployments. In the present work, we focus on the creation of a Service-‐level platform intended to facilitate, from one side the integration of heterogeneous and geographically disperse Sensors and Actuator Networks (SANs), and from the other the development of horizontal services using them and the information they provide. This enabler will be used for horizontal service development and for IoT experimentation. Prior to the definition of the platform, we have realized an important study targeting not just research works and projects, but also standardization topics. The results can be summarized in the following assertions: a) Open Geospatial Consortium (OGC®) Sensor Web Enablement (SWE™) data models today represent the most complete solution to describe SANs and observations. b) OGC interfaces, despite the limitations that require changes and extensions, could be used as the bases for accessing sensors and data. c) Next Generation Networks (NGN) offer a good substrate that facilitates the integration of SANs and the development of services. Consequently a new Service Layer platform, called Ubiquitous Sensor Networks (USN), has been defined in this Thesis trying to contribute to fill in the previous gaps. The main highlights of the proposed USN Platform are: a) From an architectural point of view, it follows a two-‐layer approach (Enabler and Gateway) similar to other enablers that run on top of NGN (like the OMA Presence). b) Data models and interfaces are based on the OGC SWE standards. c) It is integrated in NGN but it can be used without it over open IP infrastructures. d) Main functions are: Sensor Discovery, Observation Storage, Publish-‐Subscribe-‐Notify, homogeneous remote execution, security, data dictionaries handling, monitoring facilities, authorization support, protocol conversion utilities, synchronous and asynchronous interactions, streaming support and basic resource arbitration. . v .

(14) In order to demonstrate the functionalities that the proposed USN Platform can offer to future IoT scenarios, some experimental results have been addressed in three real-‐life small-‐scale proofs-‐of concepts (Smart Metering, Smart Places and Environmental monitoring) and a study for semantics (in-‐vehicle information system). Furthermore we also present the current use of the proposed USN Platform as an Enabler to develop experimentation and real services in the SmartSantander EU project (that aims at integrating around 20.000 IoT devices). . . . vi .

(15) Table of Contents Agradecimientos ..................................................................................................................... i Resumen ................................................................................................................................. iii Abstract .................................................................................................................................... v 1 1.1 1.2 1.3 . 2 . Introduction .................................................................................................................... 1 Motivation ........................................................................................................................ 4 Objectives ......................................................................................................................... 5 Structure ........................................................................................................................... 7 . Concepts and Terminology in the Internet of Things ....................................... 9 . 2.1 Introduction .................................................................................................................... 12 2.2 Sensor and Context Definition ........................................................................................ 13 2.2.1 Sensor Definition ..................................................................................................... 13 2.2.2 Context definition .................................................................................................... 14 2.2.3 Categorizations of Context ...................................................................................... 15 2.2.4 Context-‐aware features .......................................................................................... 17 2.2.5 Phases of Context .................................................................................................... 17 2.2.6 Conclusions about Context and Sensor definitions .................................................. 18 2.3 Sensor Modelling and Context Modelling ....................................................................... 19 2.3.1 Sensor Modelling ..................................................................................................... 19 2.3.2 Context Modelling ................................................................................................... 22 2.4 Sensor Frameworks and Context Frameworks ............................................................... 24 2.4.1 Sensor Networks Middleware ................................................................................. 24 2.4.2 Sensor Network Framework .................................................................................... 25 2.4.3 Context Frameworks ............................................................................................... 27 2.5 Moving from the sensor domain to the context domain ................................................ 29 2.6 Standardization activities ................................................................................................ 31 2.7 Conclusions ..................................................................................................................... 32 . 3 . OGC® Sensor Web Enablement .............................................................................. 35 . 3.1 Introduction .................................................................................................................... 37 3.2 SWE 1.0 standards .......................................................................................................... 39 3.2.1 Information related Standards ................................................................................ 39 3.2.2 Interfaces related Standards ................................................................................... 41 3.3 SWE 2.0 standards .......................................................................................................... 43 3.3.1 Information related Standards ................................................................................ 44 3.3.2 Interfaces related Standards ................................................................................... 46 3.4 Other related work using OGC® SWE family of standards .............................................. 49 3.5 Analysis of the SWE ......................................................................................................... 51 3.6 Conclusions ..................................................................................................................... 55 . 4 4.1 4.2 4.3 . Next-‐Generation Communication Infrastructures .......................................... 57 Introduction – (Connectivity provider) ........................................................................... 59 Characteristics of NGN .................................................................................................... 60 IMS .................................................................................................................................. 62 vii .

(16) 4.3.1 IMS Functional Entities ............................................................................................ 63 4.3.2 Service delivery Using IMS ....................................................................................... 65 4.4 NGN Support for SANs .................................................................................................... 66 4.5 Integrating SANs into IMS ............................................................................................... 68 4.6 Conclusions ..................................................................................................................... 69 . 5 . The Ubiquitous Sensor Network Platform ......................................................... 71 . 5.1 Introduction .................................................................................................................... 74 5.2 Goals, Functions and Principles ...................................................................................... 75 5.2.1 USN Platform Functionalities .................................................................................. 76 5.2.2 USN Platform Design principles ............................................................................... 76 5.3 Reference Architecture ................................................................................................... 76 5.4 Functional components .................................................................................................. 79 5.4.1 USN-‐Enabler ............................................................................................................ 80 5.4.2 USN-‐Gateway .......................................................................................................... 85 5.5 Communication Protocols ............................................................................................... 86 5.6 Data Models .................................................................................................................... 87 5.6.1 Resource Description ............................................................................................... 88 5.6.2 Observations and Measurements ........................................................................... 89 5.7 Call Flows ........................................................................................................................ 89 5.7.1 Sensor Publishing .................................................................................................... 90 5.7.2 Application Subscription .......................................................................................... 90 5.7.3 Observation Publishing ........................................................................................... 91 5.7.4 Actuator .................................................................................................................. 92 5.8 Deployment .................................................................................................................... 93 5.9 Performance and Scalability Analysis .............................................................................. 96 5.10 Implementation .............................................................................................................. 97 5.11 Analysis of the Solution ................................................................................................... 98 5.12 Integration with the SmartSantander architecture ...................................................... 100 5.13 Conclusions ................................................................................................................... 102 . 6 6.1 6.2 6.3 6.4 6.5 6.6 6.7 . 7 7.1 7.2 7.3 7.4 7.5 . . Use Cases ..................................................................................................................... 105 Technical description of the use cases .......................................................................... 107 Smart Metering ............................................................................................................. 109 Environmental monitoring ............................................................................................ 113 Smart Place ................................................................................................................... 115 SmartSantander ............................................................................................................ 119 In Vehicle Information System ...................................................................................... 120 Conclusions ................................................................................................................... 122 . Conclusions and Future Work .............................................................................. 125 Main Novelties .............................................................................................................. 128 Fulfilment of the Objectives .......................................................................................... 128 Contributions ................................................................................................................ 129 Future work ................................................................................................................... 131 Main Publications and Dissemination Activities ........................................................... 133 . viii .

(17) Bibliography ...................................................................................................................... 137 . ix .

(18)

(19) Table of Figures Figure 1: Role of the Internet of Things Platforms ........................................................................ 3 Figure 2: Lifestyle Management using wearable computer [Roggen2006] ................................ 16 Figure 3: From sensor information to context information ........................................................ 19 Figure 4: Multiple context frameworks on top of a sensor framework ...................................... 30 Figure 5: Sensor data pyramid .................................................................................................... 30 Figure 6: Standardization view .................................................................................................... 31 Figure 7: Role of the Sensor Web Enablement [OGC07_165] ..................................................... 38 Figure 8: Evolution of the SWE Standard from the first generation to the Next ........................ 44 Figure 9: NGN Basic Reference Model. ([ITU2004b]) .................................................................. 61 Figure 10: IMS architecture ......................................................................................................... 63 Figure 11: High-‐level view of the USN Platform .......................................................................... 79 Figure 12: Functional decomposition of the USN Enabler .......................................................... 81 Figure 13: Gateway Architecture ................................................................................................ 85 Figure 14: Resource Model (SensorML System) ......................................................................... 88 Figure 15: Sample of a Sensor Publishing ................................................................................... 89 Figure 16: Sample of Application Subscription ........................................................................... 90 Figure 17: Sample of Observation Publishing ............................................................................. 91 Figure 18: Sample of an Actuator Call ......................................................................................... 93 Figure 19: Examples of USN-‐Enabler Deployments .................................................................... 94 Figure 20: Examples of USN-‐Gateways Deployments ................................................................. 95 Figure 21: USN-‐Platform implementation .................................................................................. 97 Figure 21: Smart Santander Architecture ................................................................................. 102 Figure 22: Use cases deployments ............................................................................................ 108 Figure 23: WS&AN architecture ................................................................................................ 109 Figure 24: Examples of the devices used in the Smart Metering demo .................................... 110 Figure 25: Map of the Contazara Indoor deployment .............................................................. 111 Figure 26: Images of the Smart Metering deployments ........................................................... 112 Figure 27: Smart metering application ..................................................................................... 112 Figure 28: Examples of the devices used in the Environmental monitoring demo ................... 113 Figure 29: Example of the Environmental Monitoring application ........................................... 114 Figure 30: Screen located in the entrance hall in the Smart Place scenario ............................. 115 Figure 31: Screen located in the meeting room of the Smart Place scenario ........................... 117 Figure 32: Screen of the meeting organizer for the Smart Place scenario ................................ 118 Figure 33: Deployment map of the Smart Places scenario ....................................................... 118 Figure 34: Pictures of the Sensor Nodes used in the Smart Places scenario ............................ 119 Figure 35: Map of the initial deployment for the SmartSantander project .............................. 119 Figure 36: Pictures of the Sensor Nodes used in the SmartSantander project ......................... 120 Figure 37: In-‐Vehicle Information System Use Case ................................................................. 121 Figure 38: Adding Semantic features to the Smart Device and Telco USN Platform ................ 122 . xi .

(20)

(21) Intelligent Context-‐Aware Services based on Internet of Things Architectures . 1 Introduction. . 1 .

(22)

(23) Intelligent Context-‐Aware Services based on Internet of Things Architectures . 3 . Contemporary society is continuously demanding more services based on smart environments. Smart grids, smart metering, home automation, eHealth, logistics, transportation, environmental monitoring are just some depicting examples of the new wave of services that will be widely used in the next forthcoming years. The level of maturity achieved in some of the base technologies, like Sensor Network communications or semantics, envisions feasible solutions to the problems. Furthermore, we are currently observing how new applications are being developed tailoring small deployments for the aforementioned use cases. However these services are often tightly coupled to the sensor networks and sometimes they even depend on specific hardware on which the software and services are supposed to run. All of this makes them very costly to maintain, to be adapted to similar but different environments, to change their technologies, or even to replicate them for other uses cases. In other words, these current solutions are still far away from becoming generally applicable. Even assuming that some of the current drawbacks could be solved, approaching a vertical solution for each use case is from a business point of view unfeasible. Sensor network infrastructures, despite the advances, will still be expensive to deploy, operate and maintain. Finding synergies among different domains to share infrastructures is not a good business practice, but a necessity for their viability. Furthermore, thinking about more advanced, user centric context-‐aware, long-‐tail services, it can be foreseen that they won’t be possible if it will be necessary to deploy specific infrastructures for them. Their only chance will be sharing and reusing other deployments. Under this context, developing horizontal platforms that will allow multiple services to use a single deployment and at the same time, each deployment being used by different applications is of paramount importance. The Future Internet (FI) technologies in general and the Internet of Things (IoT) in particular will be their main drivers. This vision is summarized in Figure 1, where IoT platforms act as glue elements between a set of application services, categorized under 4 main types, developed reusing a common baseline of infrastructure deployments. . Figure 1: Role of the Internet of Things Platforms. .

(24) 4 Introduction . 1.1 Motivation Recent predictions [Botterman2009] foresee the Internet of Things (IoT) to form an essential part of the Future Internet, as its connected devices will outnumber the computers and mobile devices utilised by human users by orders of magnitude. In fact, most of the big companies, Telecom Operators, suppliers, solution providers, etc. are investing important resources to develop new products to position themselves in these future markets. Despite the efforts, a full realization of the IoT vision is still far from being achieved. As pointed out in [Gluhak2009], Heterogeneity of edge devices, Information explosion and privacy, Importance of metadata, “Freshness” of information, Mobility, Information flows and traffic patterns are some of the most important challenges that need to be solved. Considering all of them and the high scalability issues posed by the number of devices connected, it is inconceivable testing solutions using small deployments or simulations. For this reason, it is of vital importance providing experimentation facilities. Current IoT experimental infrastructures are centred in providing sensor-‐network communication experimentation. However, the level of maturity achieved at the networking level justifies the increasing demand on the research community to shift IoT testbed facilities from the network to the service and information management areas [Bernat2011]. In this evolution, service platforms play a key role, since they must facilitate the interaction among services, infrastructures and the information they generate. However, advanced IoT platforms that cope with all the challenges described before are still far away from being a reality [Hernandez2011]. Moreover, theses architectures will need to be validated against large-‐scale experimentation solutions. In the mean time, less ambitious but equally important platforms that bridge the needs of service and information experimentation are needed. Therefore, they should simplify service interactions by, from one side, offering a set of useful functions and from the other by integrating heterogeneous sensor infrastructures in a common way. Consequently requirements for such experimentation platforms are: • • • • •. •. • •. . Promote the integration of existing deployments. Manage heterogeneous devices and functionalities, ranging from very low-‐power battery-‐operated devices to very powerful and capable ones. Support the co-‐existence of heterogeneous sensor-‐network communication protocols Facilitate the diversity in the long-‐range communications (different access and core networks). Break the verticality allowing applications to use the information offered by multiple infrastructures and also facilitating an infrastructure to be used by several applications. Decouple applications from the sensor infrastructures: The interaction should be independent regardless the protocols, data models and particularities of the infrastructure. Be independent on the application domain: It should support at the same time applications and infrastructures belonging to different fields. Keeping always high levels of security and privacy. .

(25) Intelligent Context-‐Aware Services based on Internet of Things Architectures Two aspects are key factors to be considered in the design of the service platforms: from one side, the functionality they provide, and, from the other, the communication infrastructures and protocols. Traditionally the integration of real world information into the digital world has been mainly addressed in two different research fields: Sensor and Actuator Networks (SANs) and Context-‐ awareness [Raz2006]. These two different paradigms have leaded to two clearly related but not convergent architectures to offer real world information. It is important to analyse, reuse and complete existing solutions and standards in the field to build an ecosystem that facilitates constructing the future IoT platforms. Sensor and Actuator Networks (SANs) will be used in a big variety of deployments with completely different characteristics and requirements at different levels: communication infrastructures (Internet, Operator Networks), protocols (IP, ZigBee, Bluetooth, etc.), speed (almost real-‐time, occasional, etc.), etc. Furthermore, considering the significant work that is being carried on in the definition of the Future Internet, it is likely that new infrastructures and protocols will be developed. Service platforms should act as the narrow-‐waist layer facilitating applications being independent on the communication infrastructures and protocols. This view will not just facilitate the development of services but also the evolution of applications and sensor infrastructures thanks to the decoupling. The definition of an IoT service platform that copes with all the needs is not a trivial task and a lot of different research activities worldwide are working in this area. In fact, the present work does not aim at providing a full solution. However, it depicts an open framework where a set of basic functions are provided in a modular and secure way so many new features could be later added. Furthermore, proposals like the way in which context and sensor features should be combined (presented in chapter 2), provides also architectural guidance for the future IoT developments. Finally, it is important to note that a platform that fills these requirements is not just useful for experimentation, but also for final service development. . 1.2 Objectives The main objective of this dissertation is the definition of a Service Level platform that facilitates the development of applications that use information from the environment, mainly offered by Sensor networks. This architecture, which paves the initial path towards the creation of future IoT platforms, can be used for both, context-‐aware service development and experimentation. In order to achieve this ambitious overall goal we have identified a series of scientific and technological objectives that will be addressed in the present dissertation. To define the main concepts and terms used along the time in the Internet of Things area. Despite IoT is a new term, similar concepts, like Ubiquitous computing, Ambient Intelligence or Real Word Internet have been used. Describing them together with the main technologies (sensor networks, context-‐awareness, information modelling, etc.) and trends will not just . . 5 .

(26) 6 Introduction clarify them but also will offer the existing building blocks over which new solutions will be proposed. To review the State-‐of-‐the-‐Art at research, development and standardization levels so that advantages, limitations and needs for improvements could be discovered. IoT related technologies have been prolific in the research and standardization areas. Comparing, reusing, extending and, when required, defining new features, should be a mandatory activity in the definition of any new system. To analyse the suitability of the OGC SWE standards as the base ground for applications to interact with the information provided by sensors. The Open Geospatial Consortium (OGC®) Sensor Web Enablement (SWE ™) family of standards have been widely used in the research community to access sensors and sensor data systems, especially in environmental monitoring use cases. It is worth to study if these standards could be used as bases for defining the interfaces between services and IoT platforms. To study how suitable are Next Generation Networks (NGN) to integrate Sensor Networks. NGN have proven to offer good features to develop and deploy new services (independence on the network, security, billing, trust, integration of heterogeneous devices, etc.). These facilities, together with the broad coverage that current operator networks offer for deploying sensors, makes a good match worth to consider. To define a concrete set of goals, functions and principles that lead the definition of a platform targeting IoT service level experimentation. The envisioned platform should be build based on a set of clearly defined principles and goals that head the concrete definition steps. The previous section already provided a hint about some of them. To describe a proper combination of the main technological trends that will help achieving future solutions. Sensor Networks frameworks and Context-‐aware frameworks offer different ways of offering services each one with advantages and disadvantages. On the other hand, OGC SWE standards offer good solutions for applications to interface sensor information, however it lacks proper support for communication, which is clearly provided by the NGN. Defining from one side an intelligent combination of sensor network and context-‐aware systems, and from the other NGN with OGC is more than avoiding reinventing the wheel; is a way to explode synergies. To specify, prototype and analyse the platform and its components. The platform must be specified and decomposed in modular components performing specific functionalities. These components should offer interfaces that are used in the scope of system operations that interact with others in sequences of call flows. In a second step, the defined architecture should be prototyped to validate and refine the specification. Moreover, it must be analysed from an architectural point of view considering among others scalability issues. To validate the platform with the implementation of real-‐life use cases that demonstrate the benefits of the developed solutions. Some use cases, targeting potential context-‐aware services, must be designed and implemented targeting different and heterogeneous settings trying to cover some of the key aspects that need to be researched. They would allow us to . .

(27) Intelligent Context-‐Aware Services based on Internet of Things Architectures test, validate, and even improve –when necessary– the interoperability among different platform instances under realistic settings. . 1.3 Structure The Thesis has been divided in 7 chapters, including the present one, according to the following structure: Chapter 2 provides an introduction to the main terms, concepts and technologies used in the research domain of the Thesis, like Internet of Thinks, Ambient Intelligence, Ubiquitous Computing, etc. It also describes the context-‐aware process and the role played by the sensor systems. Modelling, architecture solutions and standardization activities in the sensor and context domains are additionally scrutinized. Finally, a novel architectural approach to offer both context and sensor information using a reliable architecture style is presented. Chapter 3 introduces and analyses the Open Geospatial Consortium ® (OGC) Sensor Web Enablement ™ (SWE) family of standards. This group of standards involves more than 25 specifications covering mainly information models and interface definitions. They have been evolving through the time, and currently a second version is being released. This section describes their capabilities, limitations and space for improvements to be used under the scope of Internet of Things. Additionally, it reviews their impact in the research and real field trials deployment areas. Chapter 4 complementarily to the previous Chapter focuses on main communication issues. It first introduces the main connectivity solutions (PSTN and Internet). Then overviews the Next Generation Network (NGN) architectures and characteristics, paying special attention to IP Multimedia Subsystem (IMS), which acts as the control plane of NGN. Next, an analysis of the properties and drawbacks offered to integrate Sensor Networks is presented. Finally, it scrutinizes the existing approaches of integrating sensor networks into IMS. Chapter 5 represents the main block of the Thesis, as it describes the Ubiquitous Sensor Network (USN) platform. The first part of the Chapter justifies the need for IoT Service level experimentation. Then it defines the main set of goals, principles and objectives of the USN Platform followed by the technology trends that have inspired and influenced its design. Next, the architecture of the platform is described by outlining its components, call flows and implementation issues. Then an evaluation study including scalability analysis and comparison with other works is presented. Finally, the Chapter concludes presenting how the proposed USN Platform is being integrated into the SmartStantander architecture, one of the most recent IoT experimentation facilities. Chapter 6 highlights the different testbeds that have been implemented using the proposed USN Platform, which are a Smart Metering, Environmental Monitoring, Smart Places and the In-‐vehicle Information System. Furthermore, the current deployments of the SmartSantander, which use the platform, are also described. Finally, Chapter 7 presents the main conclusions and future work of this Thesis.. . 7 .

(28)

(29) Intelligent Context-‐Aware Services based on Internet of Things Architectures . 2 Concepts and Terminology in the Internet of Things . . 9 .

(30)