- The connectivity provided by the ICT infraestruture;
- The applications that can be used to request, use or monitor services;
- The underlying data in the city data lake – enabling understanding about the interactions produced, the patterns and the behaviors, how to optimize traffic flow or waste management.
Have the ability o manage with formal and non-formal forms of human and machines interaction – operational technology and the pervasive communication infrastructure – nevertheless, still requires a number of considerable advancements, in particular, in the domain of understanding human behavior  as an important data source of the city planning and service evolution.
Cognitive cities may be constituted with  many richly interacting adaptive components that include human beings and other entities with sufficient awareness – sensors – reconfigurability, learning, autonomy and cooperation capabilities at materialized in a City operating system. However, the value of the City OS is if it scales across multiple cities in an ecosystem. In this sense, the objective is to create a Smart City operating system, an “universal-platform” for cities. While they acknowledge the competitive nature and that each city has its own character, identity, tax system or unique capabilities (healthcare or education) there are more commonalities than there are differences. Apart of common services like energy or waste management, the approach is how the ecosystem City OS, connected to other cities can evolve, for example in areas like traffic management, mobility as a service, safety, once the algorithms will be trained in larger data sets or sharing a common capability like person digital identity or resilience (cyber-attacks, geopolitical conflicts, diseases, resources shortages).
 Cognition Digital Twins for Personalized Information Systems of Smart Cities: Proof of Concept – Jing Du, Qi Zhu2, Yangming Shi, Qi Wang, Yingzi Lin and Daniel Zhao
 Cognitive cities and intelligent urban governance – Ali Mostashari, Friedrich Arnold, Mo Mansouri, and Matthias Finger