Since the Internet-of-Things (IoT) has been introduced, it is considered as one of the emerging technologies providing great opportunities to many vertical industries. One of the major IoT application areas that gets significant attention is smart city. Since it is unrealistic to expect full convergence toward a single IoT platform in the near future, it is mandatory to enable interworking between different platforms based on multiple standards, coexisting in the emerging smart cities. In this paper, we take the example of two global IoT standards, FIWARE and oneM2M, which are actively used in many smart city projects, and analyze them to show the feasibility of IoT platforms interworking. Based on the analysis, we design and implement a novel IoT interworking architecture providing a semantic driven integration framework suitable for smart city. The core idea behind our approach is to introduce interworking proxies that: 1) conduct a static mapping of sensor information between IoT platforms and 2) perform semantic interoperability using semantically annotated resources via a semantic interworking proxy that dynamically discovers new kinds of information and adapts itself to enable automatic translation of semantic data between given source and target IoT platforms while it is running. We present the system based on these proxies and evaluate it in Santander smart city. The results demonstrate that it is able to discover and manage IoT sensors connected to both oneM2M and FIWARE. It appears that the semantic approach provides the flexibility and dynamic adaptivity needed for fast growing and rapidly changing urban environments.

With the advancement of Internet-of-Things (IoT) technology, various domains, such as smart factories and smart cars have used this new technology to provide value-added services. In addition, technologies, such as multiaccess edge computing (MEC) and network slicing provide another opportunity for the IoT to support more advanced and real-time services that could not have been previously supported. However, the simple integration of such technologies into the IoT does not take the full advantage of MEC and network slicing or the reduction of latency and traffic prioritization, respectively. Therefore, there is a strong need for an efficient integration mechanism for IoT platforms to maximize the benefit of using such technologies. In this article, we introduce a novel architectural framework that enables the virtualization of an IoT platform with minimum functions to support specific IoT services and host the instance in an edge node, close to the end user. As the instance provides its service at the edge node, where the MEC node and network slice are located, the traffic for the end user does not need to traverse back to the cloud. This architecture guarantees not only low latency but also efficient management of IoT services at the edge node. To show the feasibility of the proposed architecture, we conducted an experimental evaluation by comparing the transmission time of both IoT services running on the central cloud and those using sliced IoT functions in the edge gateway. The results show that the proposed architecture provides twice as much transmission speed as that from the conventional cloud-based IoT platform.

The Internet of Things (IoT) aims to change many aspects of people's daily lives by extending the scope of computing to the physical world, and thus shift the environment of computing more to a distributed and decentralized form. The amount of IoT devices and their collaborative behavior causes new challenges to the scalability of traditional software testing, and the heterogeneity of IoT devices increases costs and the complexity of coordination of testing due to the number of variables. In this paper, we introduce IoT Testing as a Service-IoT-TaaS, a novel service-based approach for an automated IoT testing framework aims to resolve constraints regarding coordination, costs, and scalability issues of traditional software testing in the context of standards-based development of IoT devices, and explore its design and implementation. IoT-TaaS is composed of remote distributed interoperability testing, scalable automated conformance testing, and semantics validation testing components adequate for testing IoT devices. To provide a conceptual overview, we analyze its technical and systemic advancement and compare it to traditional testing with concrete examples.

Modern cities are deploying smart, safe, and sustainable smart city services. However, such services are largely fragmented across cities because they are being developed based on proprietary IoT solutions or using different IoT standards. This creates a strong need to develop an approach to bridge disconnected smart cities and provide interoperability. Therefore, the aim of this article is to provide a guideline to mayors and other city officials for interconnecting their smart cities with other smart cities for interoperability. For this purpose, we propose three interworking models that can be selected based on the status of the cities to be connected with each other. All these models enable the continuity of IoT services between cities using different technologies, that is, a standardized interface, interworking proxy, and semantics. As only one model cannot be adapted to all the connected city cases, we thoroughly compare and analyze the models followed by introducing the pros and cons of each model.

With the advancement of the Internet of Things (IoT), different use cases, such as smart factories, smart cities, and smart cars are being developed. Technologies, such as multiaccess edge computing (MEC) and network slicing are being researched to support various vertical use cases. However, simply utilizing network slicing and MEC is insufficient when providing a specific IoT service. Accordingly, there is a need for a method of arranging and operating common service functions (CSFs) used in the IoT platform at the edge of the network. In addition, it is necessary not only to deliver virtual CSFs but also to implement autoscaling policies of these virtual common service resources. This study extends the idea of resource slicing technologies for the IoT service layer. The IoT service layer exposes the virtual IoT CSFs as an IoT slice service to be provided in the form of virtual network functions (VNFs) with MEC applications on top of the network function virtualization infrastructure (NFVI) at the edge of the network. We propose a framework architecture for virtual IoT slice service orchestration, and illustrate how to instantiate the virtual IoT service functions in the existing centralized cloud to the MEC platform. We also propose an elastic computing algorithm of virtual IoT slice services functions(vIoT-SSFs) resources at the NFVI so that the IoT applications and underlying IoT resources can access vIoT-SSFs at the edge of the network.

As the Internet of Things (IoT) is evolving rapidly in various verticals, such as smart cities and smart industries, the number of IoT applications is growing exponentially. Standardized conformance testing mechanisms are widely used to test software applications, including IoT applications. However, current conformance testing mechanisms require continuous human intervention and additional software to be embedded into a target device being tested, which is time consuming, costly, and requires additional memory on the target device. Therefore, there is a considerable need to enhance and optimize existing conformance testing so that it is adequate for automatically testing highly distributed constraint IoT applications. In this paper, we propose a novel mechanism for automated and scalable conformance testing for IoT applications by introducing a test triggering mechanism based on a standardized test interface. This triggering mechanism is based on several new logical components in a testing environment that exchange messages between a testing system and a target IoT device. This technique of automatic conformance testing can lessen the cost and human intercession to decrease the number of missteps and accelerate the IoT market by certifying IoT applications.