6.2 Objective Functions
Objective functions define the optimization goals of the Urban Value Field Economics (UVFE) framework. They quantify the performance of an urban system and provide measurable criteria for evaluating alternative planning strategies, infrastructure investments, and policy decisions.
Unlike conventional optimization approaches that focus on a single objective, UVFE adopts a multi-objective optimization framework in which economic, social, environmental, and spatial objectives are optimized simultaneously. The objective is not merely to maximize economic returns but to achieve a balanced and sustainable Urban Value Field.
The general optimization problem can be expressed as
subject to
and the corresponding planning, environmental, financial, and governance constraints.
Each objective function represents a different dimension of urban performance.
5.2.1 Economic Value Maximization
The primary economic objective is to maximize the total urban value generated by the Urban Value Field through efficient allocation of land, infrastructure, investment, and economic activities.
where
is the Urban Value Field;
denotes the urban study area.
This objective seeks to maximize the overall economic value of the city.
5.2.2 Social Welfare Maximization
Urban optimization should improve the quality of life and social well-being of residents by enhancing public services, education, healthcare, housing, and social inclusion.
where
represents the Urban Social Welfare Index.
5.2.3 Accessibility Optimization
Accessibility is one of the principal drivers of urban value. Optimization aims to improve connectivity among residential areas, employment centers, public services, and transportation networks.
where
denotes the Accessibility Index.
Improved accessibility enhances value creation and value propagation throughout the Urban Value Field.
5.2.4 Environmental Quality
Urban development should preserve environmental quality while supporting economic growth. This objective minimizes environmental degradation and promotes sustainable land use.
where
is the Environmental Quality Index.
Typical indicators include air quality, green space, carbon emissions, ecological connectivity, and environmental resilience.
5.2.5 Urban Resilience
Urban systems should maintain functionality under uncertainty, disasters, climate change, and economic shocks.
where
is the Urban Resilience Index.
This objective measures the adaptive capacity and recovery capability of the Urban Value Field.
5.2.6 Balanced Development
Balanced development seeks to reduce spatial inequality and promote equitable distribution of urban value across different districts and communities.
One possible objective is
where
represents the spatial variation (or inequality) of the Urban Value Field.
Minimizing spatial disparities contributes to balanced regional development and equitable access to urban opportunities.
The overall Urban Value Optimization problem can therefore be formulated as
subject to the physical, economic, environmental, financial, and institutional constraints governing the Urban Value Field.
Within the UVFE framework, these objective functions provide a comprehensive evaluation of urban performance by integrating economic efficiency, social welfare, accessibility, environmental sustainability, resilience, and spatial equity into a unified optimization framework. They establish the mathematical foundation for the optimization models presented in the following sections.