# IoT-Enabled Smart Cities: Evolution and Outlook
## 3 Key Technologies Developed
### Smart City Applications  
Citizens living in smart cities expect a lot from their smart cities [82]. For example, smart cities are expected to leverage various ICT technologies to improve legacy city services and reduce the cost of living. Therefore, smart city services and their applications can extend into many diverse domains [83]. There is a smart city regulation in South Korea that classifies the smart city services into ten categories; administration, transportation, health, environment, security, disaster prevention, infrastructure management, education, culture & tourism, logistics, and employment [84].  
There are many different ways to classify smart city services and applications. We have already shown this in Section 2. For example, we can see that existing smart city services in different cities (e.g., sizes, locations, regulations, and time) have significant differences in the strategy and solutions that they have adopted.  
In this section, as summarized in Table 3, various smart city applications that run on top of smart city platforms using smart city APIs are introduced and classified based on our comprehensive review in Section 2. In particular, we classify smart city services into four high-level categories and provide several key smart city applications in each smart city application category.  
* **Smart transportation:** This type of application is intended to establish a demand-responsive transportation system by installing transportation infrastructure suitable for the era of autonomous driving and providing consumer-oriented transportation services.
* **Smart environment:** This type of application introduces the latest smart water management technology for water resource management and water disaster prevention, and presents a water management leading model in waterfront cities.
* **Smart energy:** This type of application introduces new and renewable energy and establishes an energy demand management system to increase the energy independence of the city.
* **Smart security:** This type of application provides fast and accurate civil safety services by applying solutions using innovative technologies related to disaster and safety.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Category** & **Application** & **Description** \\ \hline \multirow{5}{*}{Smart Energy} & Building energy management system & Provides a system that monitors building energy consumption in real time using IoT devices and automatically optimizes and controls and manages energy production and use. \\  & & & Uses eco-friendly and renewable energy to secure energy independence and provide an energy transaction system between individuals. \\ \cline{2-3}  & \multirow{2}{*}{Energy efficient building} & \multirow{2}{*}{\begin{tabular}{c} Uses eco-friendly and renewable energy to secure energy independence and provide an energy transaction system between individuals. \\ \end{tabular} } \\  & & Virtual power plant & \begin{tabular}{c} Integrates the operation of small-scale distributed power facilities such as solar energy and household energy storage systems (ESS), and manages it as a single power plant. \\ \end{tabular} \\ \hline \multirow{5}{*}{Smart Security} & Intelligent CCTV & \begin{tabular}{c} Secures golden time by reducing human analysis errors and analysis time by real-time prediction of crime occurrence signs using visual intelligence technology and AI. \\ \end{tabular} \\  & \multirow{2}{*}{School zone security} & \
\begin{tabular}{c} Secures commuting safety by linking information tracking the movement of students and vehicles around the school zone with vehicle information and introducing an accident prevention system. \\ \end{tabular} \\ \cline{1-1} \cline{2-3}  & Disaster prediction &
\begin{tabular}{c} Prevents large-scale accidents by monitoring terrain changes and underground buried conditions with drones, satellites, and IoT sensors, and predicting AI-based ground subsidence. \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table}
Table 3: _Cont._