Many of the natural as well as man-made complex systems are highly organized, extensively networked, and modular in both structure and function. They could be studied with 'complex networks' paradigm with the aim of modeling and understanding their structure, function, dynamics and design.

Airport Network of India
Aviation infrastructure, with its complex web of connectivity and dynamics over it, presents an interesting case of complex system. We analyzed and enumerated the Airport Network of India (ANI), a representative model of Indian's aviation infrastructure system. The study led to some interesting results vis-a-vis world-wide-wide airport network and insights into the dynamic and fast-growing network that ANI is. It would be interesting to model airport networks aimed at engineering efficient infrastructure, resilience to targeted attacks, and robust against spread of contagious diseases. The last point has especially become important in the light of recent examples of emergence of epidemics such as SARS and swine flu, the global spread of which is largely supported by the aviation infrastructure.

BLOG: Airport Networks: Design, Efficiency and Emergence of Pandemic

Biological Networks
With the sequencing of many genomes and advances in high throughput techniques, much information about details of many biological processes as well as macromolecular structures. Graph theoretical paradigm facilitates modeling of these systems as "networks" -- i.e., systems composed of elements interacting among each other in a complex manner.

Diseases as Complex Networks

Protein structures as Complex Networks

Brain Networks