Aldo Rossi introduced 'historicism' and 'collective memory' to urban design. Rossi also proposed a 'collage metaphor' to understand the collection of new and old forms within the same urban space. Peter Calthorpe developed a manifesto for sustainable urban living via medium density living. He also designed a manual for building new settlements in his concept of Transit Oriented Development (TOD). Bill Hillier and Julienne Hanson introduced Space Syntax to predict how movement patterns in cities would contribute to urban vitality, anti-social behaviour and economic success. 'Sustainability', 'livability', and 'high quality of urban components' also became commonplace in the field. Today, urban design seeks to create sustainable urban environments with long-lasting structures, buildings, and overall livability. Walkable urbanism is another approach to practice that is defined within the "Charter of New Urbanism". It aims to reduce environmental impacts by altering the built environment to create smart cities that support sustainable transport. Compact urban neighborhoods encourage residents to drive less. These neighborhoods have significantly lower environmental impacts when compared to sprawling suburbs. To prevent urban sprawl, Circular flow land use management was introduced in Europe to promote sustainable land use patterns. As a result of the recent New Classical Architecture movement, sustainable construction aims to develop smart growth, walkability, architectural tradition, and classical design. It contrasts from modernist and globally uniform architecture. In the 1980s, urban design began to oppose the increasing solitary housing estates and suburban sprawl. Managed Urbanisation with the view to making the urbanising process completely culturally and economically and environmentally sustainable, and as a possible solution to the urban sprawl, Frank Reale has submitted an interesting concept of Expanding Nodular Development (E.N.D.) that integrates many urban design and ecological principles, to design and build smaller rural hubs with high-grade connecting freeways, rather than adding more expensive infrastructure to existing big cities and the resulting congestion. Throughout the young existence of the Urban Design discipline, many paradigm shifts have occurred that have affected the trajectory of the field regarding theory and practice. These paradigm shifts cover multiple subject areas outside of the traditional design disciplines. There have been many different theories and approaches applied to the practice of urban design. New Urbanism is an approach that began in the 1980s as a place-making initiative to combat suburban sprawl. Its goal is to increase density by creating compact and complete towns and neighborhoods. The 10 principles of new urbanism are: walkability, connectivity, mixed-use and diversity, mixed housing, quality architecture and urban design, traditional neighborhood structure, increased density, smart transportation, sustainability, and quality of life.