The term intelligent city (IC) has been used with various meanings. At least five different descriptions of what an intelligent city is can be found in the literature:
- Initially ICs have been defined as virtual reconstructions of cities, as virtual cities (Droege, 1997). The term has been used broadly as an equivalent of ‘digital city’, ‘information city’, ‘wired city’, ‘telecity’, ‘knowledge-based city’, ‘electronic communities’, ‘electronic community spaces’, ‘flexicity’, ‘teletopia’, ‘cyberville’, covering a wide range of electronic and digital applications related to digital spaces of communities and cities (MIMOS).
- Another meaning was given by the World Foundation for Smart Communities, which links smart cities with smart growth, a development based on information and communication technologies. ‘A Smart Community is a community that has made a conscious effort to use information technology to transform life and work within its region in significant and fundamental, rather than incremental, ways’ (California Institute for Smart Communities, 2001).
- ICs were defined as intelligent environments with embedded information and communication technologies creating interactive spaces that bring computation into the physical world. From this perspective, intelligent cities (or intelligent spaces more generally) refer to physical environments in which information and communication technologies and sensor systems disappear as they become embedded into physical objects and the surroundings in which we live, travel, and work (Steventon and Wright, 2006).
- Intelligent cities were also defined as territories that bring innovation and ICTs within the same locality. The Intelligent Community Forum (2006) has developed a list of indicators that provide a framework for understanding how communities and regions can gain a competitive edge in today’s Broadband Economy. Being an IC it takes a combination of: (1) significant deployment of broadband communications to businesses, government facilities and residences; (2) effective education, training and workforce able to perform knowledge work; (3) policies and programs that promote digital democracy by bridging the digital divide to ensure that all sectors of the society and citizens benefit from the broadband revolution; (4) innovation in the public and private sectors and efforts to create economic clusters and risk capital to fund the development of new businesses; and (5) effective economic development marketing that leverages the community’s broadband to attract talented employment and investments.
- Along the same line, intelligent cities (communities, clusters, regions) were defined as multi-layer territorial systems of innovation that bring together knowledge-intensive activities, institutions for cooperation in learning and innovation, and digital spaces for communication and interaction in order to maximize the problem-solving capability of the city. The distinctive characteristic of an intelligent city is the high performance in the field of innovation, because innovation and solving of new problems are main features of intelligence (Komninos 2002 and 2006).
The three dimensions of intelligent cities 
Intelligent cities evolve towards a strong integration of all dimensions of human, collective, and artificial intelligence available within a city. They are constructed as multi-dimensional agglomerations combining three main dimensions (Komninos 2006, 17-18; Komninos 2008, 122-123).
- The first dimension relates to people in the city: the intelligence, inventiveness and creativity of the individuals who live and work in the city. This perspective was described by Richard Florida (2002) as ‘creative city’, gathering the values and desires of the ‘new creative class’ made by knowledge and talented people, scientists, artists, entrepreneurs, venture capitalists and other creative people, which have an enormous impact on determining how the workplace is organized, whether companies will prosper, whether cities thrive or wither.
- The second dimension relates to the collective intelligence of a city’s population: ‘collective intelligence is the capacity of human communities to evolve towards higher order complexity and harmony, through such innovation mechanisms as differentiation and integration, competition and collaboration. ’ (Atlee and Pór 2006). This dimension is based on the institutions of the city that enable cooperation in knowledge and innovation.
- The third dimension relates to artificial intelligence embedded into the physical environment of the city and available to the city’s population: communication infrastructure, digital spaces, and online problem-solving tools available to the city’s population.
Thus the concept of ‘intelligent city’ integrates all the three aforementioned dimensions of the physical, institutional and digital spaces of an agglomeration. Consequently, the term ‘intelligent city’ describes a territory with (1) developed knowledge-intensive activities or clusters of such activities; (2) embedded routines of social co-operation allowing knowledge and know-how to be acquired and adapted;(3) a developed communication infrastructure, digital spaces, and knowledge / innovation management tools; and (4) a proven ability to innovate, manage and resolve problems that appear for the first time, since the capacity to innovate and to manage uncertainty are the critical factors for measuring intelligence.
Smart City is a relative concept. However, smart city research and literature seem putting more emphasis on embedded systems, sensors and interactive media, while intelligent cities rely more on collective intelligence / collaborative intelligence, innovation system, and web-based collaborative spaces. In any case both concepts try integrating the above mentioned three dimensions of urban space (physical, social, and digital).
Intelligent cities vs.digital cities 
All intelligent cities are digital cities, but all digital cities are not intelligent (Komninos 2002, 195-201). The difference is in the problem solving capability of intelligent cities, while the ability of digital cities is in the provision of services via digital communication. Take the following examples: (1) the administration of a city -or a local community- offers online (via its web portal) services that already was providing offline. This is a typical case of digital city offering online services for the citizen. (2) A group of people /organizations creates new products / services using digital spaces of consultation and online collaboration among the citizens. This is a typical case of intelligent city creating services with the involvement of citizens (by the citizens). In the second case, the digital space becomes a tool that contributes to the capacity of the community to use collective intelligence and engineer new solutions to people needs.
As general rule, we may say that in services provision by local administrations, digital cities are placed downstream between the public authority and the citizen as recipient of services (as digital marketplaces); while intelligent cities are placed upstream between the citizens and the public authority, enabling co-creation and co-design of services (as Living lab). This view explains why the main building blocks of intelligent cities are related to innovation and problem solving processes, such as competitive intelligence, technology absorption, collaborative product development, and new product promotion.
Intelligent environments are digital spaces in which the digital interaction goes out of the computer and becomes embedded into buildings and infrastructures of the city. Intelligent environments can be combined both to digital cities, automating the delivery of services, and to intelligent cities as well, automating the collection and processing of information along new product / service development.
More efficient cities 
Intelligent cities create more effective urban systems capable of addressing contemporary challenges and urban problems. They create more innovative and competitive cities, based on knowledge clusters, people-led innovation, and global networking; offering higher capacity of monitoring and management of environmental issues; improved city transportation; more secure urban spaces. This greater effectiveness is based on solutions /platforms integrating human, collective and artificial intelligence (in other words urban activities, institutional capacity, and IT). Some major fields of intelligent city activation are:
|------- Innovation economy -------||------- Urban infrastructure -----||----------- Governance -----------|
|- Innovation in industries, clusters, districts of a city||- Transport||- Administration services to the citizen|
|- Knowledge workforce: Education and employment||- Energy / Utilities||- Participatory and direct democracy|
|- Creation of knowledge-intensive companies||- Protection of the environment / Safety||- Services to the citizen: Quality of life|
University research labs have developed prototypes and solutions for intelligent cities. MIT Smart Cities Lab  focuses upon intelligent, sustainable buildings, mobility systems (GreenWheel Electric Bicycle, Mobility-on-Demand, Citycar, Wheel Robots); the IntelCities  research consortium developed solutions for electronic government, planning systems and citizen participation; URENIO has developed a series of intelligent city platforms for the innovation economy  focusing on strategic intelligence, technology transfer, collaborative innovation, and incubation, while is offering, through its portal, a global watch on intelligent cities research and planning ; the Smart Cities Academic Network  is working on e-governance and e-services in the North Sea region.
Large IT and telecommunication companies such as CISCO, IBM, MS have developed new solutions and initiatives for intelligent cities as well. CISCO, launched the Global Intelligent Urbanization initiative  to help cities around the world using the network as the fourth utility for integrated city management, better quality of life for citizens, and economic development. Microsoft is working with Coventry University and Birmingham City Council on the Intelligent City Proof of Concept  which is an interoperable technology platform focusing on transport. IBM announced its SmarterCities  to stimulate economic growth and quality of life in cities and metropolitan areas with the activation of new approaches of thinking and acting in the urban ecosystem.
Fundamental processes 
Intelligent (smart) cities are deploying online services in different sectors of cities - the local economy and development, environment, energy, transport, security, education, health, trade, housing, governance; and in different districts of cities - the CBD, financial, university, marketplace, port, airport, technology, and industrial districts.
These various domains of the intelligent city rely on a few knowledge processes, which are present regardless the sector /district of the city. Fundamental knowledge processes which sustain intelligent cities are: broadband communication, interactive services, use of smart devices and agents, intelligence gathering, creative behavior, collective intelligence, upgrade of skills, innovation, monitoring and measurement. Integration is a key-factor, enabling the above processes to work together and create environments more efficient in collaborative problem-solving and innovation. See also spatial intelligence of cities.
Intelligent cities and globalization 
Recent publications on intelligent cities stress the convergence of innovation systems and virtual environments in creating global systems of innovation (Bell et al. 2009; Komninos 2008; IJIRD 2009). As open innovation theory came to show, the emphasis has now shifted from the internal in the company innovation process to external innovation networks and knowledge environments, which have now taken on global dimensions. Virtual spaces and embedded systems are generating a wave of new hybrid environments (global digital ecosystems, living labs, i-hubs, COINs, smart cities, e-gov,digital cities, u-communities, intelligent environments, etc.) which amplify networking, experimentation and innovation on a global scale.
See also 
- Smart city
- Collaborative innovation network
- Collaborative intelligence
- Collaborative software
- Knowledge ecosystem
- Swarm Intelligence
- The Wisdom of Crowds
- Droege, P. (ed.), (1997) Intelligent Environments - Spatial Aspect of the Information Revolution, Oxford, Elsevier.
- California Institute for Smart Communities, (2001) Ten Steps to Becoming a Smart Community.
- Steventon, A., and Wright, S. (eds), (2006) Intelligent spaces: The application of pervasive ICT, London, Springer.
- Intelligent Community Forum, (2006) What is an Intelligent Community.
- Komninos, N. (2002) Intelligent Cities: Innovation, knowledge systems and digital spaces, London and New York, Routledge.
- Komninos, N. (2006) The Architecture of Intelligent Cities, Conference Proceedings Intelligent Environments 06, Institution of Engineering and Technology, pp. 53-61.
- Florida, R. (2002) The Rise of the Creative Class and how It's Transforming Work, Leisure, Community and Everyday Life, New York: Basic Books.
- Atlee, T. and Pór, George (2006) Collective Intelligence by Tom Atlee and George Pór, Evolutionary Nexus: connecting communities for emergence.
- Bell, R., Jung, J., and Zacharilla L. (2009) Broadband Economies: Creating the Community of the 21st Century, New York, Intelligent Community Forum.
- Komninos N. (2008) Intelligent Cities and Globalization of Innovation Networks, London and New York, Routledge.
- IJIRD (2009) Intelligent Clusters, Communities and Cities: Enhancing innovation with virtual environments and embedded systems, Special Issue, International Journal of Innovation and Regional Development, Vol. 1, No. 4.