Chapter 13 Internet of Things: A Context-Awareness Perspective Davy Preuveneers and Yolande Berbers Contents 13.1 Introduction ......................................................................................288 13.1.1 Software Architecture and the Internet of Things .....................288 13.1.2 Context Awareness and the Internet of Things ...........................289 13.1.3 Convergence as a Key Enabler for the Internet of Things ...........290 13.2 State-of-the-Art on Context-Aware Computing for Nonintrusive Behavior .......................................................................290 13.2.1 A Definition of Context .............................................................291 13.2.2 Using RFID to Sense Context....................................................291 13.2.3 Requirements for Representing and Exchanging Context ..........292 13.3 Trends in Context-Aware Computing within Service Orientation ..........296 13.3.1 Context-Enabled Service Oriented Architecture and the Semantic Web ................................................................296 13.3.2 Context-Enabled Service Delivery Platforms ..............................297 13.4 Service Provision in a Context-Aware, Converged Service Architecture ............................................................................................299 13.4.1 Context Management as an Enabling Service ...........................300 13.4.2 Conveying Context and Distributed Storage ..............................301 287 AU5281_C013.indd 287 12/3/07 12:39:07 PM 288 n The Internet of Things 13.5 Context Awareness from RFID to the End-User in the Internet of Things .........................................................................303 13.6 Conclusions .......................................................................................304 13.7 Open Issues ............................................................................................305 References .........................................................................................................305 13.1 Introduction The next wave in the era of computing will be outside the realm of the traditional desktop. In the Internet of Things paradigm (IoT) [22], everything of value will be on the network in one form or another. Radio frequency IDentification (RFID) and sensor network technologies will give rise to this new standard, in which infor- mation and communication are invisibly embedded in the environment around us. Everyday objects, such as cars, coffee cups, refrigerators, bathtubs, and more advanced, loosely coupled, computational and information services will be in each others interaction range and will communicate with one another. Large amounts of data will circulate in order to create smart and proactive environments that will sig- nificantly enhance both the work and leisure experiences of people. Smart interact- ing objects that adapt to the current situation without any human involvement will become the next logical step to people already connected anytime and anywhere. With the growing presence of WiFi and 3G wireless Internet access, the evolution toward ubiquitous information and communication networks is already evident nowadays. However, for the Internet of Things vision to successfully emerge, the computing criterion will need to go beyond traditional mobile computing scenarios that use smartphones and portables, and evolve into connecting everyday existing objects and embedding intelligence into our environment. For technology to dis- appear from the consciousness of the user, the Internet of Things demands: (1) a shared understanding of the situation of its users and their appliances, (2) software architectures and pervasive communication networks to process and convey the contextual information to where it is relevant, and (3) the computational artifacts in the Internet of Things that aim for autonomous and smart behavior. With these three fundamental grounds in place, smart connectivity and context-aware compu- tation via anything, anywhere, and anytime can be accomplished. 13.1.1 Software Architecture and the Internet of Things Any software architecture, designed to be deployed within the setting of the Inter- net of Things, will need to foresee the increasing heterogeneity of devices and networks, and will have to provide for varying user and application requirements within diverse contexts of service provision. It will be essential for new architectures Internet of Things refers to a ubiquitous network society in which a lot of objects are “connected.” AU5281_C013.indd 288 12/3/07 12:39:08 PM Internet of Things: A Context-Awareness Perspective n 289 to integrate the latest technologies in the areas of software and hardware in order to assimilate as much as possible data and services available in the environment of the user. As service integration-related tasks will remain inevitable, it is no surprise that the industry is aiming for software solutions that make this integration a more trac- table activity. The evolution toward integrated service orientation is already emerg- ing in the ongoing convergence of Web services and telecommunication services [21]. Service-Oriented Architecture (SOA) [27] is an architectural style that enables the composition of applications by using loosely coupled and interoperable services. These often transaction-based services are described and exposed using open stan- dards—in the case of Web services using WSDL, SOAP, and BPEL [40]—that are independent of the underlying programming language and platform. The telecom- munications world has embraced the Service Delivery Platform (SDP) architectural approach to enable more flexible communication and collaboration services by evolv- ing to all-IP (Internet Protocol) networks for the delivery of multimedia-enabled and location- or presence-aware services. Due to its event-driven communication para- digm, an SDP differs from the previous architectural style in that a SOA typically does not need to meet any real-time demands for its data-driven communication. Both SOA and SDP software architectures commonly provision service orchestra- tion capabilities by exposing their services using open standards, and often share building blocks to handle noncore functionalities, such as authentication, identity management, and billing. As a result, converged services bring us the flexible interac- tions from the Web service paradigm, nicely integrated with the communication and collaboration services from the telecommunications world. Key to the success of the Internet of Things will be the ability to connect everyday objects, including RFID tags and other existing resources, to such service-oriented architectures so that it will lead to an overall flexible architecture that aims to create a pleasant user experience at the workplace, in public areas as well as in the home environment. 13.1.2 Context Awareness and the Internet of Things Context awareness plays an important role in the aforementioned software archi- tectures to enable services customization according to the current situation with minimal human intervention. Acquiring, analyzing, and interpreting relevant con- text information [11] regarding the user will be a key ingredient to create a whole new range of smart entertainment and business applications that are more support- ive to the user. Although context-aware systems have been in the research epicenter for more than a decade [32,33], the ability to convey and select the most appropri- ate information to achieve nonintrusive behavior on multiuser-converged service platforms in mobile and heterogeneous environments remains a significant man- agement challenge. Interoperability at the scale of the Internet of Things should go beyond syntactical interfaces and requires the sharing of common semantics across all software architectures. It also demands a seamless integration of existing com- putational artifacts (hardware and software) and communication infrastructures. AU5281_C013.indd 289 12/3/07 12:39:09 PM 290 n The Internet of Things Only then can context information be successfully shared between highly adaptive services across heterogeneous devices on large-scale networks that consider this information relevant for their purposes. 13.1.3 Convergence as a Key Enabler for the Internet of Things In summary, the Internet of Things is all about convergence, from connected com- puting using RFID and sensor technology to digital content and context-aware services, an observation that was also made in the digital lifestyle chapter of the digital.life ITU Internet Report 2006 [23]. The success of the Internet of Things will not so much depend on the development of new technologies, but more so on con- necting and integrating existing resources, ranging from small-scale objects, such as RFID tags, up to large-scale software systems that serve thousands of clients at a time. The goal is to create a software architecture that enables objects to exchange information through the Internet to achieve nonintrusive behavior and custom- ized services. Part of the architecture’s responsibility is to make sure that relevant information arrives at the right place in a way that the recipient understands what it receives. Here, we investigate how such an architecture can be designed by inte- grating innovative scientific results from related research domains with industrial technologies and practices with a proven track record. In section 13.2, we describe the current state-of-the-art in context-aware