Runtime Monitoring of IoT Services to Guarantee Properties

Ensuring that a critical information infrastructure remains in a safe and secure state is a mandatory requirement. When IoT services related to such an infrastructure are open to the internet, existing execution monitoring technologies do not work well to protect it; internal malware may compromise and subvert the monitoring mechanism itself, and the safety properties will interact with its security property. In this chapter, an isolation-based solution is proposed to enforce property policies for runtime IoT services. First, the issue of isolation-based service trace observation is addressed by establishing and modelling a virtual channel. Then, the issue of isolation-based policy enforcement is discussed, and the incompleteness and inconsistency of trace knowledge observed in the virtual channel is addressed. Finally, physical systems are introduced into the proposed runtime monitors, and the controllability of IoT services is discussed as an example of the enforcement of service properties. Several experiments are carried out to demonstrate this solution.

Streamlining Service Platform for Integrating IoT Services

IoT scenarios involve both smart devices hosting web services and very simple devices with external web services. Without unified access to these types of devices, the construction of IoT service systems would be cumbersome. The basic principle of this chapter is the integration of distributed events into SOA. The data access capability of physical entities is first separated from their actuation capability, which acts as a foundation for ultra-scale and elastic IoT applications. Then, a distributed event-based IoT service platform is established to support the creation of IoT services and allow the hiding of service access complexity, where the IoT services are event-driven; the design goals are impedance matching between service computation and event communication. The coordination logic of an IoT service system is extracted as an event composition that supports the distributed execution of the system and offers scalability. Finally, an application is implemented on the platform to demonstrate its effectiveness and applicability.

IoT Resource Access and Management

In most existing IoT applications, IoT resources are not fully open and shared with “silo” utilization solutions. Although IoT resources are constructed based on semantic models, it is still necessary to establish a resource management platform to support automatic resource access, resource discovery, resource lifecycle management, and resource utilization. This chapter presents an IoT resource management characteristics that can be used to address these issues. Physical systems and devices are connected to the resource accessing utility using a two-layer method, which involves recognizing/installing physical communication drivers and composing communication protocols. A hierarchical mapping method is used to build graphical IoT resource models, helping users to quickly and correctly specify IoT resources and deploy them. A resource platform based on the resource management characteristics is provided to support resource storage, updating, lookup, utilization, and so on.

Summary

In previous chapters, the design of IoT services using the streamlining and integration principle was discussed. In this chapter, a summary is given of how to use these principles to achieve IoT service provisioning, and an example is given. The event streamlining problem is first discussed from an IoT service provisioning perspective, involving how to efficiently disseminate the sensing events among event producers and consumers on demand. The service integration problem is then considered, which requires dynamic coordination of the relevant IoT services based on events occurring in the real world. An EDSOA is abstracted from the perspective of utilizing the advantages of EDA and SOA, and the streamlining and integration principle is viewed from an architectural perspective. A combination of SOA and EDA can easily support the on-demand dissemination of sensing information and event-driven service dynamic coordination. The example used here is a deployed CMCS application.

Distributed Access Control for IoT Services Based on a Publish/Subscribe Paradigm

With IoT services becoming more open and covering wider areas, different IoT applications at different sites are now collaborating to realize real-time monitoring and controlling of the physical world. The use of a publish/subscribe paradigm allows IoT applications to collaborate more closely in real time and to be more flexible. This is due to the space, time, and control decoupling of the event producer and consumer, which can be used to establish an appropriate communication infrastructure. Unfortunately, a publish/subscribe-based IoT application does not know which users are consuming its data events, and consumers do not know where the events originate from. In this environment, the IoT application cannot directly control access, since interactions in the application are anonymous and indirect. To address these issues, this chapter first describes a foundation for communication between wide-area IoT services and then defines a security model supporting a data-centric methodology. Using this model, the underlying network capabilities can be integrated to help IoT applications control event access. The key concept in this access control solution is the preservation of the interaction characteristics of publish/subscribe-based IoT applications, which are both anonymous and multicast. Thus, two specific types of event are used to accomplish requests for and granting of authorization, while remaining consistent with the publish/subscribe paradigm. A policy-attachment method is used to preserve the anonymity and multicast features of the collaborating IoT applications, where policy-matching efficiency, policy privacy, and communication performance are the main points of focus. This access control scheme can also be enhanced with confidentiality.

Coordinating Stateful IoT Resources as Event-Driven Distributed IoT Services

In IoT applications, physical systems have not only discrete behaviors but also continuous dynamics; the corresponding aspects of the information world are called IoT resources. IoT services monitor and control these resources to ensure specific properties such as controllability and stability. An approach is proposed here that links together IoT resources, events, and IoT services based on requirement specifications. IoT resources are explicitly modelled as stateful to express the evolution of their current attributes and states from their previous ones. Multiple actions are modelled by specifying the indirect effects and causalities of their actions, and the interactions between physical processes and information processes are orchestrated as the coordination of the IoT resources (i.e., coordinating stateful IoT resources as IoT services). At runtime, the issue of how to solve the glitch problem is discussed based on an event extraction method. Finally, an evaluation is performed as a proof of concept for this chapter.

A Publish/Subscribe-Based Service Bus for Integrating and Streamlining Event-Driven IoT Services

In IoT scenarios, numerous things and services are connected and coordinated via distributed events. Hence, a service bus needs to be established to streamline these events to enable the efficient and stable coordination of IoT services as an integrated service system. However, without an awareness of the coordination requirements of the application, the publish/subscribe-based service bus will not be optimally utilized to deliver real-time and coherent sensor events, and at the same time, service concurrency and scalability cannot be maximally realized. In this chapter, a service-oriented publish/subscribe middleware is proposed as a base for the construction of a distributed, ultra-scale, and elastic service bus for IoT applications. In order to establish this publish/subscribe service bus, the service coordination logic is then extracted from an event-driven business process, and the coordination logic is translated into the event matching and routing functions of the publish/subscribe middleware.

IoT Resources and IoT Services

Although many IoT applications have been developed, a theoretical basis for interconnecting all things is still obscure. In order to establish a solid foundation for IoT applications, this chapter addresses three issues: how to model physical sensors and devices as IoT resources, how to introduce IoT resources into IoT services, and how to use distributed events to connect IoT resources and IoT services together to form an IoT service system. An IoT resource is defined by its static attributes and dynamic lifecycle; both of these are specified using semantic knowledge to enable automatic sharing and understanding. An IoT service is considered as a set of actions imposed on IoT resources to monitor and control the physical world. An example application is given in order to demonstrate a proof of concept for event-driven IoT services over IoT resources (streamlining events) to integrate IoT services.