boundary Agglomeration 1 Beijing [China] 1 Beijing(Jing)-Tianjin(Jin)-Hebei(Ji) (JJJ) urban agglomeration 1 Beijing(jing)-tianjin(jin)-hebei(ji) (JJJ) urban agglomeration 1 Berlin 1 Berlin Wall 1 CG-GSO model 1 China 1 Comprehensive gravity-gram schmidt orthogonalization coupling model model 1 Coupling models 1 Economic and social effects 1 Economics 1 Forecasting 1 Gram-Schmidt orthogonalizations 1 Gray forecast 1 Gray forecasts 1 Hebei 1 Obstacle factor 1 Obstacle factors 1 Planning 1 Regional planning 1 Regional scale 1 Sustainable development 1 Tianjin 1 Urban agglomerations 1 Urbanization 1 Wim Wenders 1 agglomeration 1 city 1