the increasing rate of urbanization and rate of population growth over the 20th century has led to various problems such as traffic congestion, air pollution, and lack of open and green spaces that have affected the cities and their citizen's life. this condition has led to increasing demands for more land use, homes, and work places, more public transport and mass transit systems and mode...

The underground economy has long been of interest to economists and has devoted extensive studies to itself in economic literature. Through fuzzy logic approach in present research, we estimated the size of underground economy of Iran over the period of 1978-2010. For this purpose and according to theoretical bases and previous studies, variables such as GDP per capita, ratio of direct taxes to...

The increasing rate of urbanization and rate of population growth over the 20th century has led to various problems such as traffic congestion, air pollution, and lack of open and green spaces that have affected the cities and their citizen's life. This condition has led to increasing demands for more land use, homes, and work places, more public transport and mass transit systems and modern in...

during a very long period of time, civil engineers have been the only ones to be designated as the experts for underground space, while the planners and architects were the ones of the development at the surface. cities worldwide tend to overlook an invaluable asset that lies beneath their surfaces. most cities and urban regions are unaware of the benefits underground space use has to offer, bo...

the underground economy has long been of interest to economists and has devoted extensive studies to itself in economic literature. through fuzzy logic approach in present research, we estimated the size of underground economy of iran over the period of 1978-2010. for this purpose and according to theoretical bases and previous studies, variables such as gdp per capita, ratio of direct taxes to...

The foundation framework for underground spatial data aims to establish the platform for the underground spatial data sharing and integrating. The reasons lie in that: a) the long-term development of city construction has accumulated abundant underground spatial data and information; b) the development and utilization of city underground space demands for clear, detailed and visualized comprehe...

Urban underground space is an important non-renewable resource, and its value has increased in recent decades. Economic change and development is the most fundamental motive of evolution of the urban space, it also affected urban underground spatial development in a large degree. The paper try to analysis the urban economic affection in mechanism of evolution of urban underground space. The onl...

a r t i c l e i n f o We provide a theoretical and empirical study of the relation between financial development and the size of the underground economy. In our theoretical framework agents allocate investment between a low-return technology which can be operated with internal funds, and a high-return technology which requires external finance. Firms can reduce the cost of funding by disclosing...

With the fast development and utilization of underground space resource in cities, the spatial distribution of urban underground pipelines becomes more and more complex. How to efficiently utilize the latest technology, realize underground space resources' management, visualization, layout optimization and mine applications, are challenging issues in current digital city development. Taking int...