# Smart Cities of the Future as Cyber Physical Systems: Challenges and Enabling Technologies
## 3 IoT Technologies in Smart Cities of the Future
### Challenges and Enabling Technologies
#### 3.1.1 Need for Convergence of IoT Technologies  
The mirroring of IoT objects can be a catalyst for supporting interoperability with IoT devices that support different communication protocols or semantic representations, as well as for significantly enhancing privacy and security aspects by protecting the IoT device through its digital twin (DT) in the edge part of the infrastructure [28]. This perfectly matches with the idea proposed by the _I/OCloud_ concept exploiting the Stack4 Things framework and presented in [29]. This can also enable IoT on a larger scale by using smaller and cheaper IoT devices that are able to perform sensing and basic computational functionalities, while pushing the heavier computational functionalities at the edge or cloud part of the infrastructure. Through the interpretation of different types of semantics, IoT devices and CPS systems can be managed in a neutral way in terms of semantic representation, while the collected information can be automatically interpretable and integrable by the edge and cloud part of a smart city application, avoiding lock-in in a specific modeling approach. With regard to the semantic interoperability, various information models targeted to the \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Main Challenge** & **Sub-Challenge** & **Enabling Technology** \\ \hline \multirow{2}{*}{\begin{tabular}{l} Need for convergence of \\ IoT technologies \\ \end{tabular} } & IoT Communication Protocols Interoperability & Digital Twins \\  & IoT Devices Semantic Interoperability & Digital Twins, IoT Semantic Models \\  & Privacy and Security Aspects & Digital Twins, IoT Cybersecurity mechanisms \\ \hline \multirow{2}{*}{\begin{tabular}{l} IoT applications development \\ and management \\ \end{tabular} } & Development of distributed and self-adaptive & Cloud-native principles, Microservices-based \\  & IoT applications & Applications, Containerization \\  & Software modularity and reusability & Generic IoT functions/enablers \\ \hline \multirow{4}{*}{\begin{tabular}{l} Improve Intelligence \\ and Automation \\ \end{tabular} } & Dynamic Orchestration Mechanisms & Cloud/Edge Computing Orchestrators \\  & Automation & Cloud/Edge Computing Orchestrators, Artificial \\  & Intelligence, Control Theory & Intelligence, Control Theory \\  & Massive IoT Deployments & 5G, IoT Network Slicing \\  & Context Awareness & IoT Semantic Models, Distributed Data \\ \hline \multirow{4}{*}{\
\begin{tabular}{l} Human-centric solutions \\ \end{tabular} } & Tactile and haptic communications & Design of human-centric interfaces, Tactile \\  & Internet technologies & Internet of Skills (IoS), Augmented \\  & Involving human-in-the-loop & Reality/Virtual Reality \\ \hline \multirow{2}{*}{
\begin{tabular}{l} Efficient IoT data storage, \\ representation and management \\ \end{tabular} } & Data management over structured and & IoT Semantic Models, IoT data lakes, \\  & unstructured data & knowledge graphs \\ \cline{1-1}  & Distributed data management and analysis & Federated Learning, Distributed AI \\ \cline{1-1}  & Data Privacy and Security & Blockchain \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The mapping of challenges to enabling technologies. development of CPS have been made available, such as the W3C Web of Things [30], OMA IPSO Smart Objects [31], FIWARE NGSI-LD [32], and Web5G [33] specifications. Upon the usage of such models, efficient and secure data sharing based on distributed data management and data monetization schemes can be realized (e.g., through blockchain-based techniques), unleashing the potential for IoT data exploitation by various stakeholders [34]. .1.2 IoT Application Development and Management Taking Advantage of 5G/Edge Computing Infrastructure  
Moving one step further, modularity, openness, and interoperability should be supported by design toward the development of distributed and self-adaptive IoT applications.