An IoT Framework for Heterogeneous Multi-layered Access in Smart Cities.

The proliferation of the Internet of Things has been instrumental in the digitalization of smart cities, where various technologies are leveraged to enable data utilization. However, achieving interoperability among diverse technologies remains a challenge due to heterogeneity. In this regard, ontologies have been proposed as a standalone solution that semantically enriches IoT data. Nevertheless, ontologies are still underutilized due to several limitations as systems become more complex. In order to overcome these limitations and provide a single point-of-access for all smart city layers, this paper presents a theoretical IoT framework that minimizes the requirement of interdisciplinary knowledge to operate IoT platforms, while utilizing existing ontologies in a complementary manner to build a high-level ontology schema. The framework is comprised of five fundamental axes/pylons that enable frictionless usage and configuration in order to extract data from all employed smart city layers via an adapter. This can be beneficial for smart cities such that legacy or under-utilized IoT platforms can be integrated with the framework and provide additional information reducing the costs. External operators, applications and platforms can configure the axes in order to extract data regarding their needs and make better decision making.