Electrical and Electronic Engineering - Theses
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ItemA Blockchain-based Solution for Sharing IoT Devices( 2022)The Internet of Things (IoT) includes billions of sensors and actuators (which we refer to as IoT devices) that harvest data from the physical world and send it via the internet to IoT applications to provide smart IoT solutions. These IoT devices are often owned by different organizations or individuals who deploy them and utilize their data for their own purposes. Procuring, deploying, and maintaining IoT devices for exclusive use of an individual IoT application is often inefficient, and involves significant cost and effort that often outweigh the benefits. On the other hand, sharing IoT devices that are procured, deployed, and maintained by different entities (IoT device providers or simply providers) is efficient, cost-effective and enables rapid development and adoption of IoT applications. Currently, most IoT applications themselves procure, deploy, and maintain the sensors they need to collect the IoT data they require as there is limited support for sharing IoT devices and their costs. Therefore, there is a need for developing an IoT device sharing solution that allow IoT applications to 1) discover already deployed IoT devices, 2) use discovered IoT device data (IoT data) for their own purposes, and 3) share-cost of IoT device deployment via a “pay-as-you-go” model similar to cloud computing. To address the aforementioned problems, in this thesis we propose, develop, implement, evaluate, and validate a solution namely IoT Devices Sharing (IoTDS). IoTDS enables scalable and cost-efficient discovery and use of IoT devices by IoT applications. IoTDS incorporates services for IoT device registration, IoT device query, IoT device payment and IoT device integration. To support these services, we propose 1) a novel IoTDS ontology, an extension of Semantic Sensor Network (SSN) ontology to describe IoT devices and their data to enable IoT device registration and query services. The IoTDS ontology also provides for describing the payment and integration information that is used by IoT device payment and integration service; 2) a special-purpose blockchain namely IoTDS Blockchain that has been developed specifically to support the needs of the IoTDS services i.e., supporting decentralised and scalable query, integration and payments services for IoT devices and applications. Specifically, IoTDS Blockchain incorporates a distributed semantic triple store and functions to register IoT devices, and specialised transactions for supporting IoT device payments (we propose a new cryptocurrency namely SensorCoin); 3) a novel IoT marketplace (IoTDS marketplace) that offers an interface and a protocol (IoTDS protocol) to support the interactions between IoT devices, IoT applications, IoTDS Blockchain, and IoTDS services. IoTDS solution 1) facilitates IoT devices deployed across the globe by different providers to be queried by any IoT application; we term this global, 2) enables via the IoTDS Blockchain a non-ownership model; we term this IoT-owned i.e., no individual/organisation owns it or controls it, 3) able to handle the vast and ever-increasing number of IoT devices and IoT applications; we term this scalable, and 4) able to support and integrate heterogenous of IoT devices and their data; we term this interoperable. In this thesis, we provided implementation details of IoTDS services that includes IoTDS ontology, marketplace, and blockchain. the IoTDS ontology has been modelled using Protegee and Owl and implemented using RDF. The IoTDS Blockchain and corresponding functions are implemented using NodeJS and Web Socket. The IoTDS marketplace and corresponding IoTDS protocol has been implemented using NodeJS and MQTT. We conducted large-scale experimental evaluation of IoTDS solution by deploying it on Nectar cloud (20 instances) using both real and simulated (5,000,000) IoT devices and IoT applications (5000) to assess and validate the scalability and performance of IoTDS. We also developed and validated a mathematical model that can be used to estimate the performance of the IoTDS with the increasing number of IoT devices. Experimental outcomes show that the proposed IoTDS solution performs great (linear scalability) in supporting global discovery, use, and cost-share of large numbers of IoT devices and applications. The main contributions of this thesis are 1) an IoTDS solution for sharing IoT devices, 2) a survey of techniques for supporting IoT device sharing; 3) a special purpose Blockchain to support sharing of IoT devices, 4) a novel Marketplace to support registration, querying, payment, and integration of IoT devices, 5) a novel protocol for autonomic control of integrating IoT devices and fetching their data, and 6) an implementation and experimental evaluation of the IoTDS solution.
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ItemA software-defined networking framework for IoT( 2020)In recent years, we have witnessed a shift from traditional internet networks interconnecting computers based on well-established standards, towards a pervasive network of networks that provides internet connectivity even to the smallest physical objects. This Internet of Things (IoT) network is an enabling technology to the next industrial revolution (aka Industry 4.0) where the operational technology meets the information technology or computer-based world. The creation of new IoT applications across special context such as smart cities, smart homes, smart agriculture, etc., are realised upon sensors and actuators. The networking of sensors and actuators has extended the scope of networked sensing technologies such as Wireless Sensor Networks (WSNs). However, the networking of wireless sensor devices, or sensor nodes, imposes several challenges due to their inherent resource limitations such as computational capabilities, energy, memory, and communication bandwidth. The management of the limited resources of WSNs becomes challenging and its complexity increases as the network size grows. Thus, the current state of WSNs would not be able to meet the IoT requirements unless appropriate solutions to the aforementioned challenges are found. The focus of this thesis is to investigate the challenges and benefits of Software- Defined Wireless Sensor Networks (SDWSNs) as a solution to flexible resource management and reconfiguration of WSNs. In short, the contributions of this thesis are as follows. (i) the feasibility and practicability, of SDWSNs, to perform network and resource management was demonstrated. This research work shows the ease of managing: the network topology and the transmission power of sensor nodes, using a centralized controller without any firmware modification. (ii) The previous research work is extended to an SDN-based management system for IP sensor networks and compare it with the Routing Protocol for Low-Power and Lossy Networks (RPL) to show the advantages of removing energy- and processing-intensive functions from sensor nodes. This contribution also presents, for the first time, the control overhead metric of an SDWSN, and compare it against a WSN running RPL. (iii) Next, the effects in network performance when making the WSN reprogrammable were examined by, proposing a model-based characterisation of energy consumption to calculate the energy consumed and control overhead introduced for small, large and ‘pseudo-dynamic’ SDWSNs. (iv) Last, the benefit of SDWSNs to augment the network lifetime, whilst keeping the control overhead low, was demonstrated by, proposing an energy-aware routing protocol for software-defined multihop wireless sensor networks, that seeks to prolong the overall network lifetime of the sensor network while also maintaining a high packet delivery ratio. Extensive simulation and experimental results were carried out, to validate the benefits and impacts in network performance, for all aforesaid research works. This thesis also puts forth SDWSN as a potential pathway to overcome the rigidity in management that currently exists in WSNs.