Complex Systems Group (CxSy Group)

Research Areas

Land use optimization continues to be a focal point in developing sustainable and resilient cities that can mitigate undesirable phenomena such as overcrowding, traffic jams or air/noise pollution. To meet the challenges posed by rapid urbanization, ageing population, energy cost, environmental constraints, among others, a way to quantify the similarity and difference of existing land allocations among cities is essential. Such measures may allow comparison on the quality of life and general wellness of the residing population, hence a step closer towards achieving an objective metric for properly representing the city’s sustainability index.

The team has demonstrated that by combining the relative mixing of distinct entities (business, residential, industrial) in a given area and how they are relatively spread over the entire locality, we were able to quantify the degree of similarity and distinctiveness of land design attributes among cities. In particular, we have developed a procedure using spatial entropy and index of dissimilarity to capture the distinctness of the dispersion and aggregation forces between the different land use types. We show that the combination of these two opposing forces will also allow us to reconstruct the spatial emergence of land use of Singapore as well as other Northern American cities. Finally, the above insights have allowed us to develop an interactive tool that forecasts the surface temperature of specific land parcels in Singapore.

An efficient, resilient, scalable and properly planned Rapid Transit System (RTS) is critical for the creation of a liveable city. This is of particular interest in land-scarce Singapore where it is optimal for its residents to adopt public transport as their primary mode of transportation. As the RTS can cater to a greater volume of commuters with a higher throughput, it can significantly reduce congestions and decrease the city’s carbon footprint and reduce pollution. Coupled with good energy efficiency, the RTS offers a green and sustainable transport option for urban Singapore.

The team has developed tools to help transport planners model transport system dynamics, and examine “what-if” scenarios and proposed policies. In particular, the team characterized the route choices and travel patterns of commuters in Singapore’s Rapid Transit System (RTS) by developing an integrated set of complex systems methodologies including mathematical and statistical mechanics, as well as agent-based modelling. The resulting tools are useful for identification of bottlenecks that could cause service degradation and for establishing insight into how disruptions could possibly be managed. Ultimately, the aim is to provide a versatile approach for transport planners to make quantifiable policies that optimally balance cost and convenience for a growing city.

Image courtesy of ©OpenStreetMap contributors

Singapore has continued to do well as a small city state. She has been a role model in many regards. For her to remain competitive, the island has to be able to support population growth while staying sustainable in the way the land and resources are being used. The

overall quality of life, in terms of affordable housing and transport efficiency, needs to be enhanced. However as the island gets denser, the urban fabric (land, transport, energy, waste, businesses, people) are more intertwined and inter-dependent. Urban planning has therefore become more challenging as it needs to cater to a gamut of inter-related issues. Tackling problems in one dimension may worsen the situation in other dimensions. Policies have to be more sensitive to complex, multi-faceted and non-linear relationships between all the different faculties. The evolution of a city is also dependent on the decisions made by the populace. Their decisions on employment, education, lifestyle and communities create a unique signature of the city they are a part of. Future city planning needs to be in touch of what the residents want, how they behave and how they make decisions. A more holistic approach to urban planning is hence crucial to the long-term sustainability of Singapore.

As Singapore aims to increase its population (in particular the workforce) to sustain competitive economic growth, she needs an effective landuse plan to ensure that there is sufficient space and housing to accommodate the increased population and activities. Therefore, a central feature of this plan is the ability to understand and project housing demand.

A complex interaction network between the residents of a city forms the underlying social fabric of all urban systems. Understanding the collective behaviour and the transfer of information within this network is a key factor in creating an accurate model of the urban system. 

Recently, it was shown that the presence of noise has a positive effect on the information transmission in a communication network. In order to understand and explain the mechanism behind this stochastic resonance-like effect, our team re-casted the system using Markov Chain analysis. The dynamic range of information transfer in a noisy environment can subsequently be shaped or engineered by using an adaptive thresholding method. 

The team is also investigating various other network topologies, these include the transportation networks of Singapore, online social networks as well as gene-gene regulatory networks.