Peculiarities of Formation of a Systems Approach in Domestic Urban Planning

The formation of a systems approach to urban planning in Ukraine is considered, starting from the second half of the twentieth century. Territories with a high level of urban planning development were formed at the time as a result of the development of an industrial component of the production industrial complex, which became the basis for perspective formation of urban systems as real entities. The transition to post-industrial relations causes the increase in complexity of urban systems and their study as complex, open, non-linear, socio-territorial entities capable of self-organization as a real process that takes place in their structure.


Introduction
Starting from the second half of the nineteenth century, a concentration of production is observed in the largest cities of the most developed countries of Western Europe and the United States as a result of the formation and development of capitalist socio-economic relations. It is accompanied by rapid growth of the urban population and as a consequence by the chaotic growth of cities with an extensive territorial development, formation of urban agglomerations on their basis, that gradually merge among themselves, transforming into «megapolises».
In the context of deepening the process of urbanization in the twentieth century, the necessity of finding new flexible methodological approaches that would provide opportunities for forecasting and managing the development of the largest cities, as well as centers and forms of settlement based on them, becomes paramount. This was facilitated by the emergence and dissemination in the 1960s and 1970s of a general scientific systems approach, an important methodological tool for the study of complex objects and interactions.

The urgency
The urgency of applying a systems approach in urban planning is obvious, since the basis of this discipline is the study of urban entities and their evolution as complex systems during the deployment of the process of urbanization in different states and regions.
The study of urban planning objects as a systems has a long tradition.  This approach made it possible to study the patterns and use specific positive experience of world urbanization in solving acute problems on the territory of Ukraine.
Moreover, the methodology of a systems approach that has expanded conceptual apparatus and has been in use for several decades, although it has no universal, generally accepted character and has no standardized interpretation because of the dynamic nature of processes in the field of human activity, basically allows it to be used for solving almost any task, including urban planning.
In 1999 U. L. Pivovarov defined the urban system as a spatial form of settlement of any taxonomic rank that develops around an urbanized nucleus [2]. For example, it is an autonomous city, an urban agglomeration, an urbanized area, an urbanized zone, a megalopolis, for example.
The study of the city as a system includes the use of a number of systems-representations (categories) [3], with the following being the main among them: 1. Structural representation associated with the selection of elements of the urban system and the connections between them. Thus, at a certain level of the city's development as a system, when the agglomeration formed on its basis reaches its "mature" development, a hierarchically organized planning structure of the city center appears from the historical core to the zone of influence, which is superimposed on the planning framework that provides links between individual structural elements.
The structure of the urban system is a set of interrelations between its elements that remains unchanged for a long time (at least during observation). As a rule, it is formed over a long historical period and has the most stable character in relation to its other elements.
The urban system as a whole exists because of the connections between its elements. It can be said that the connections make direct interaction between the elements (or subsystems) of the system, as well as with the elements and subsystems of the environment. Production, cultural and recreational connections are distinguished in the structure of the urban system labor.
Connections can be direct and reverse by their nature. For example, the unity of a city center with its surrounding territories may be characterized by so-called pendulum migration when labor resources commute daily to work in the city and back home to a suburban area within two hours' reach.
2. Functional representations of an urban systeman emphasizing of the set of functions (purposeful actions) of the system and its components aimed at achieving a specific goal. The existence of the urban system implies the vital activity of its functional planning organizationthe complex formation of separate functional zones, these being production, rural and recreational, and their interaction, interpenetration and relationships.
The functional unity of settlements, or the integrity of the system, is determined on the basis of interurban connections, which are manifested in inter-urban socio-economic contacts, regular movements of the population for different purposes, as well as the transportation of raw materials, semi-finished products and final products required in the production process.
3. Macroscopic imageryan understanding of the urban system as an indivisible whole, that interacts with the external environment. That is, the urban system is always considered as a holistic center of a larger hierarchical level in relation to its adjacent territories. 4. A microscopic representation, that is based on the consideration of the urban system as a set of interconnected elements and involves the discovery of the peculiarities of the environment of the structural elements of the city. 5. Hierarchical representation, based on the concept of city subsystems, which is obtained by decomposition of an urban system, that has systemic properties that should be distinguished from its element into smaller parts (in terms of the solving problem). The city system can be represented as sets of subsystems of different levels that make up the system hierarchy, which is closed at the bottom only by elements.
The hierarchical organization of the city as a system in the system of cities was considered in 1964 by the American economist geographer B. Berry.
A city is a complex system, as such it has elements, which in turn are systems acting as subsystems of its larger complex system. When its population exceeds 100 thousand people, the above-urban systems begin to form on its basisnamely, agglomeration, urbanized area, urbanized zone, megalopolis [4]. There are three main subsystems of the city at the most basic level. These are the population, the economic basis, the sphere of life. At the same time, the city is part of a system of higher hierarchical level. 6. A procedural representation that involves understanding of the urban system as a dynamic object, characterized by the sequence of its states over time. Organically applied to the analysis of the city genesis, its further development or degradation, which can be considered as a time-distributed system. In the study and further formation of the urban system, an urban education is considered within the existing administrative boundaries. In the context of agglomeration processes, wherein the industrialization of the city go beyond their traditional boundaries, there is a process of so-called extensive development of the settlement, and settlements of the suburban zone are gradually included in the structural elements of the agglomeration. The city begins to be considered as a singular entity with its suburban zone, and the new boundaries are determined on the basis of the unity of new structural formations, determined by means of connections by the method of taxonomic zoning. Gradually, a hierarchical structure is being formed including not only the urban agglomeration but also the territories external to it. Thus, a model of agglomeration and supra-agglomeration (suburban) systems emerges [5].
Depending on the impact on the environment and the nature of the interaction with other systems, the functions of the urban system may be arranged by their increasing rank: -passive existencecan be observed in the case of non-prospective settlements, situated far enough from local centers of certain hierarchical levels in the absence of developed transport infrastructure; -material for other systemswhen it comes to the disappearance of non-prospective settlements (completion of "monocities" activity, resettlement after complete destruction in case of natural or manmade disasters, etc.); -maintenance of higher rank systemsfor example, supplying labor and other resources to a city center of the agglomeration from its area of influence; -opposition to other systems (survival)observed in the case of the formation of many center agglomerations, when individual centers compete to become the main one; -absorption of other systems (expansion)occurs in the process of formation of above-urban systems; -transformation of other systems and environments (active role)inherent in the largest cities that can be identified as global (world) cities.
The city is always considered an open system that allows the exchange of energy, matter and information (for example, energy supply, labor, innovation, etc.) with the environment.
In modern conditions of post-industrial society formation, the process of perspective emergence of urban establishment as systems is complicated. There is a stratification of the subject that affects the urban system for the researcher, developer of regulatory documentation, designer, manager, investor, etc. This raises the risk of losing the idea of the integrity of the urban system.
Urban planning development of cities as a system activity cannot be reduced to the development of project documentation only. Moreover, experience in the implementation of district planning projects and master plans for individual settlements shows that even in conditions of a planned economy, it was never possible to fully reach the project indicators, and violations in the master plans of the largest cities were counted in the dozens.
In the context of the global stage of the process of urbanization, the city is considered a complex synthetic object in which the historical, economic, social, political, environmental, biological, natural and scientific laws act coherently and thus determine the existence of common mechanisms of emergence and functioning of the city as a whole.
Attempts to describe the processes of emergence and development of the city, as well as the possibilities of their regulation, are often made with the help of a synergistic approach, which mostly responds to existing challenges. The city itself is considered by this approach as a complex open nonlinear, socio-territorial system capable of self-organizationa synergistic system. According to V. G. Turkina, synergetics allows to describe many urban processes and phenomena from a single position, allows to study the internal laws of urban systems development, gives basis for certain forecasts related to urban dynamics [6]. The synergetic description, as a rule, shows that the whole arisen as a result of the action of synergetic mechanisms of dynamics, begins to have properties Innovative Technology in Architecture and Design (ITAD 2020) IOP Conf. Series: Materials Science and Engineering 907 (2020) 012077 IOP Publishing doi:10.1088/1757-899X/907/1/012077 5 that were absent in its individual parts and elements. This is fully consistent with the idea of any city. The city is not a simple sum of its separate components, it represents absolutely new object possessing new qualities inherent in it as an integral organism.
Certainly, in the formation of synergistic ideas about the city, the phenomenon of self-organization comes to the fore. Self-organization of the system is the process of evolution of a complex system; the birth of a certain orderly structure with new qualities out of the physical chaos. It includes all processes of self-structuring, self-regulation and self-reproduction.
When it comes to the historical-genetic analysis of the development of society, particularly the formation of the settlement system and its individual elements, the knowledge of laws of selforganization allows us to interpret various social entities as social structures capable of self-organization.
Nonlinear description of the formation of urban systems at certain stages of their historical development involves the formation of different types of such structures, ranging from a single city to a network of cities, agglomerations, megalopolises, that are born, change and interact with each other according to nonlinear laws. Nonlinearity means that many solutions correspond to many ways of evolution of a nonlinear system; it indicates the variety, alternative, and irreversibility of possible ways of system evolution.
The uniqueness of each city is manifested in its genetic code, economic and geographical location, natural conditions, peculiarities of historical, socio-economic, structural and planning, compositional development, silhouette formation, and corresponds to non-linear ideas about cities that can exhibit many possible types of behavior in such conditions. That is, synergetics tries to identify real mechanisms and types of behavior that allow to consider the city as a special dissipative structure capable of selforganization, the emergence of which is associated with certain conditions of the environment that generates it. Dissipativeness (openness) of the city, in other words, means the ability of the system to exchange energy, matter, and (or) information with the outside world.
Cities as real systems that are connected to the environment by many economic, social, political, cultural and other ties, show their dissipation (openness). In the process of formation of above-urban systems, the city draws the suburban space into its limits and at the same time spreads the urban way of life into the adjacent territories.
Under the influence of external factors (political, economic, social, etc.), the city can change its mode of existence from prosperity to decline.
A condition that is steadily maintained by inflows of energy and substance from the outside; the property of an open inhomogeneous urban system, which actively interacts with the environment and is able to acquire dissipativity, is defined as a disequilibrium. However, its individual elements and subsystems may have characteristics that are quite different from the average. For the urban system, disequilibrium is a rather characteristic condition. For example, the incomes of individual citizens or the housing supply of a single family are quite different from the average. The city is never isolated. The condition of the city, which is perceived as an "equilibrium" at deep examination is not such, but characterizes only a stable period of development of the nonequilibrium structure. According to synergistic consideration, disequilibrium is evaluated as a positive, creative factor of development. Achieving "equilibrium" for each city means the inability to create new socioeconomic structures, is perceived as a process that leads to stagnation or even precedes the degeneration and dying [6].
Therefore, the conditions for the emergence and existence of a city system capable of selforganization are the fulfillment of the properties of nonlinearity and dissipation. In this case, selforganization is genetically related to the appearance of small fluctuations in the previous statea random deviation of the system from equilibrium, when the changes in the external environment are not "noise" but the generator of new structures.

Research results
Features of self-organization of the urban system can be considered on the example of an industrial city. Its emergence is primarily based on the development of capitalist socio-economic relations as well as the scientific and technological progress as its consequence. The gradual transition from handicraft to machine production causes the location of industrial enterprises in the structure of cities, the formation of whole districts and zones on their basis, including storage, municipal and construction territories, as well as the development of transport and engineering infrastructure.
Territorially, the city is growing extensively, going beyond its historical boundaries and absorbing suburban territories and small settlements located therein. Subsequently, its clear structural and planning organization, including the historic core, city center, historical building area, new dispersed planning districts and suburban area, is revealed. All this indicates that the so-called "Big City" is formed with an adjacent area, which, due to the developed intensive connections, can be considered as a single formation. Parts of this formation are "mature" agglomeration, suburban zone, a zone of influence, a zone of joint interests of the center and periphery. The evolutionary stage is unfolding.
At this stage, the city already exhibits systemic qualities that can be described by specific determinations: cause-effect, functional, target, correlative ties and more.
Gradually, the negative effects of industrialization in the industrial city are brought to the fore. There is an uncontrolled development of suburban arrays of various functional purpose and, because of their overlap, the joining of suburban arrays between themselves and the central core of agglomeration, as well as the degradation or even disappearance of open green spaces, expansion of the city center to 100 -200 square kilometers and more, the emergence of functional-landscape overlap, appearance of large centers of environmental pollution, "recreational urbanization". Fluctuations are increasing.
Even the most stable multifunctional cities show an increase in chaotic processes in their structure during the fall of the main indicators of industrial production in such conditions. This increase is characterized by the appearance of centers of degrading industrial areas.
Settlements formed during the industrial period as the "monocities" with a leading industrial function that provided jobs for up to 90% of the able-bodied population, are facing the problem of the continued existence of the settlement itself. With the increase of entropy (the growth of irreversible processes), losing its stability under the influence of fluctuations, the system enters a nonequilibrium state and approaches the bifurcation phase, which in a physical sense marks the point of branching of the paths of system's evolution.
1996 can be considered the point of bifurcation for the industrial city that determines its critical condition, when at the Habitat II conference held under the auspices of the UN in Istanbul, the exhaustiveness of the industrial society was declared and the concept of the sustainable development of civilization in the context of the post-industrial era formation was conceived. Of course, this "point" is rather conditional. It was preceded by a transition period for several decades, which saw appearance of socio-economic relations focused on the development of tertiary and quaternary sectors of the economy and the "new industrialization" based on the latest technologies. Some positive experience was gained in restructuring the degraded industrial territories in the structure of cities into the so-called "ecocites", which were recognized as the first sustainable urban settlements. Therefore, the urban system undergoes two main stages in the process of self-organizationevolutional and bifurcational.
The study of the self-organization of the urban system testifies to its complete compliance with the methodological principles of the full-format synergetic modeling proposed by V. G. Budanov for application in the humanitarian sphere and interdisciplinary design. The theory proposes two structural principles of being -homeostatic and hierarchythat characterize the phase of "order", the stable functioning of the system. Meanwhile, the principles of formationnonlinearity, instability, openness, dynamic hierarchy, observabilitycharacterize the phase of transformation, the renewal of the system, ways of destruction of the old order, the chaos of testing alternatives, and the birth of the new order [7].
Passing through the point of bifurcation, the urban system continues its development along one of the possible ways of evolution. Thus, the implementation of the concept of sustainable development in the conditions of the post-industrial technological era formation stimulates the restructuring of cities on the basis of humanization, providing the diverse needs of the population, preserving the natural environment. At the same time, improvements in the economic and political spheres of the country cause new human requirements for housing, social sphere, recreation, which in turn stimulates the development of design, construction, research, etc.