The estimation shows the permanent growth in the urban population. It is estimated that in 2050, about 68% of the world's population will live in cities

while in 2018, about 55% of the world's population lived in cities. During the same period, urbanization in Europe will increase from 74% to 85% and in North America from 80% to 90% [1]. Increasing the number of cities and urban population and their need for a higher quality of life and more use of consumer resources increase urbanization problems in all areas, such as low productivity, economic instability, poverty, inequality, and social conflict [2]. These problems have led to a reduction in the population of cities in some cases. The increase in population and, consequently, the increase in resource consumption has led to the need to turn attitudes of urban management from traditional to novel urban management. Therefore, urban planners are looking for solutions based on knowledge and novel technology to overcome the problematic challenges and troubles faced by urbanization. Sustainable urban management and smart city have become two different and intertwined features in novel urban management that tried to provide an appropriate solution for urban management problems.

There is no single definition for sustainability; different definitions have been made for it based on the exploited fields of study. In general, sustainable development refers to development that, while keeping the ability of future generations to meet their own needs and requirements, meets the current needs of people in all areas such as economic, environmental, and social areas. In the urban field of study, sustainability is founded on several pillars, including environment, economy and society dimensions [2]. On the other hand, a smart city is founded on a smart society, smart physical and smart digital pillars, and contains several domains such as environment, economy, and society [3]. Due to the coverage of sustainable development issues in the concept of the smart city, a smart, sustainable city (SSC) is used instead of a smart city [4]. It is concluded that any improvement in the implementation of the smart city concept could be considered as an improvement in sustainability and moving toward sustainable urban development. The tremendous advances in digital technologies and the increase in the well-being of the people with the expansion of its use in various walks of life have led to the use of digital technologies in various aspects of urban management. Although there is no unbeatable definition for a smart city, it can be said that what is called a smart city today is the result of the widespread use of digital technologies as the core of industry 4.0 to improve the efficiency of urban systems and increase services efficiency and its sustainability [4]. Smart in smart cities means the use of smart-based technologies and artificial intelligence for the smart growth of people and governments to achieve the main goals of the smart city with a strategic orientation. Today, the industry is going to transform from the third industrial revolution to the fourth industrial revolution. In the fourth industrial revolution, known as industry 4.0, pillars are based on the use of intelligence for integrating smart city's platforms vertically and horizontally. Smart cities are expected to be one of the main users of industry 4.0, by using Information and Communication Technologies (ICT) along with physical, cyber systems (CPS) [5, 6].

The conclusive goal of the smart city is to create a new urban management perspective to cover all aspects of real urban life with a special focus on the quality of life and reduce pressure on people in a sustainable manner. For this purpose, various infrastructures have been provided for the smart city. The European Union has introduced 6 characters, 31 parameters, and 74 identifiers for smart cities. In this regard, authors have introduced physical, digital, and social infrastructure as three necessary platforms for the smart city and have provided them with 12 domains, 49 main components, and 117 sub-components [3]. The modeling of information generated using digital technologies stands at the heart of all this infrastructure to the point that some researchers have preferred the name digital city to smart city [7].

Reviewing the research done in the field of smart cities, revealed that there is no single definition for smart city, sustainable city and digital city. Examining the mentioned concepts showed the extensive overlaps of these concepts. For this reason, researchers have combined these concepts. Smart sustainable cities [8] and smart digital cities [7, 9] are examples of these combinations. In this chapter, city 4.0 has been selected to refer to all of the above-mentioned concepts and smart, sustainability and digital are considered as the main aspects of city 4.0 (Fig. 1). Vertical and horizontal integration of city 4.0 was done through information modeling technologies founded in the center point of the city. Information modeling acts like the heart of the city 4.0 and is considered as the most essential necessity of it.

Information modeling has two aspects: 1) information gathering and preparation (vertical aspect) and 2) integrated utilization of it (horizontal aspect). In the vertical aspect, modeling technologies have the task of collecting their own categorized information. At this stage, information is collected, categorized, digitized and modeled using digital technologies. Geographic information modeling, geometric information modeling, climate information modeling, building information modeling and image processing are examples of this category. On the other hand, in order to apply in a smart city, all this information must be integrated and available online for use by stakeholders (people and government). Information modeling is the starting point for the integrated utilization of all information collected from various sources such as traffic flow, parking spaces, use of spaces and buildings, energy, car accidents, weather, forests, and green spaces, natural disasters, safety, fire, waste, sewage and water resources in urban management in order to adapt urban management services to the practical needs of the people. Information modeling and its online application enable deci...