# Autonomous Cyber-Physical Systems Enabling Smart Positive Energy Districts
## 5 Relationships Between Emerging Technologies in Positive Energy Districts  
To enhance understanding of the relationships between the emerging technologies considered important for PEDS, the interactions and relationships between the different technologies are described:  
1. _Cyber-Physical System-Digital Twins:_ DTs are digital models or virtual copies of a physical environment, including CPS infrastructure that adapts to real-time physical changes, and swiftly provide beneficial solutions for PED optimization [20]. DTs constitute a promising approach to realize CPSs [90] since they enable analysis, prediction, and optimization of the interconnected physical entities (e.g., energy optimization of BEMS) and support real-time decision-making. CPSs provide DTs with real-time data and control mechanisms which enable anomaly detection in maintenance and control stages and virtual testing [91]. Together, they are important tools for facilitating autonomous systems, smart cities, and PEDs. They can be used to forecast energy demand and end-user consumption patterns, as well as to schedule dispatchable energy generation from shifting renewable energy sources on demand [92]. 2. _Cyber-Physical System-Artificial Intelligence:_ AI supplies cognitive capabilities including reasoning, learning, and decision-making to CPSs. AI enhances CPSs' data-driven insights (e.g., real-time fault detection, optimization), intelligent control (e.g., adaptive controllers, predictive maintenance), and autonomous operation (e.g., self-driving cars, drones). The evolution of AI decision-making in cyber-physical systems is inevitable and autonomous due to increased integration of connected IoT devices in CPSs [93]. As CPSs generate enormous amounts of data from sensors and other physical components, AI processes and learns from this data and optimizes the behavior of CPSs, which as a result leads to improved data produced by the CPSs. This feedback loop continuously improves system performance. CPSs and AI together are essential for meeting PED positive energy targets due to energy management automation, adaptive control of building environments, and integration of distributed renewable resources [25]. The benefits of integrating AI with CPSs include reduced need for human intervention, improvements in fault tolerance and recovery, optimization of operations and resource use, and improved management. 3. _Cyber-Physical System-Internet of Things:_ CPSs are complex multi-layered feedback systems that interact with the physical environment through the IoT, which offers pervasive sensing and communication infrastructure to CPSs [32]. CPSs may be focused on, e.g., building real-time applications or providing customized services in the context of the IoT [93]; hence, the IoT is advanced via CPSs due to the introduction of advanced control, automation, real-time processing, decision-making capabilities, and integration within physical processes enabling dynamic optimization of energy flows and system resilience. A CPS usually includes IoT elements, but not all IoT systems classify as CPSs. When CPS is the goal, the IoT is part of the infrastructure necessary to achieve it. 4. _Cyber-Physical System-Edge Computing:_ A variety of large-scale CPS applications have been widely deployed, such as smart grids, intelligent transportation, and personalized healthcare, with strict real-time requirements due to the fact that delayed outputs may give rise to unacceptable timing faults [94]. CPSs generate data that edge nodes receive and process, and, in turn, edge computing enables CPSs to meet timing constraints, reducing latency challenges. Moreover, edge computing reduces the load on central systems, making CPSs more scalable, and improves privacy by keeping sensitive data local. In addition, edge and CPS integration increases fault tolerance and can save energy in CPS systems by applying local processing. For example, in smart grids, local edge nodes manage energy distribution based on real-time data from CPS components. 5.