Complementarity and Similarity in Complex Networks

Networks are becoming ever more important in today's highly interconnected society, from telecommunication networks and social networks to power grids and the Internet. The field of Network Science seeks to uncover structure within the complex topologies of networks and the processes that govern their link formation. Many methods and models in...

Robustness of controllability and recoverability of complex networks

Network robustness describes a network's ability to provide and maintain an acceptable level of service in the face of failures and challenges to normal operation. Unfortunately, failures of networks, such as power outages in power systems, congestions in transportation networks, failures of routers on the Internet, happen frequently in our...

Spreading processes in complex networks and systems

Complex systems are made up of many interconnected components. The interactions between components further produce emerging complex collective behaviors. In most cases, a complex system can be represented as a network in which the nodes represent the elements and the connected links illustrate the interactions. The spreading process is one of...

Epidemics on Networks: Analysis, Network Reconstruction and Prediction

The field of epidemiology encompasses a broad class of spreading phenomena, ranging from the seasonal influenza and the dissemination of fake news on online social media to the spread of neural activity over a synaptic network. The propagation of viruses, fake news and neural activity relies on the contact between individuals, social media...

Performance of complex networks: Efficiency and Robustness

Network performance is determined by the interplay of underlying structures and overlying dynamic processes on networks. This thesis mainly considers two types of collective dynamics on networks, spread and transport, which are ubiquitous in our daily lives, ranging from information propagation, disease spreading, to molecular motors on...

Spreading on Networks

Spreading phenomena such as spreading of diseases, information and computer viruses are ubiquitous in nature and man-made systems, but the understanding of them is still insufficient. This dissertation focuses on the analysis of a basic mathematical model of spreading phenomena running on underlying network structures and aims to complete the...

Information Propagation in Complex Networks: Structures and Dynamics

This thesis is a contribution to a deeper understanding of how information propagates and what this process entails. At its very core is the concept of the network: a collection of nodes and links, which describes the structure of the systems under investigation. The network is a mathematical model which allows to focus on a very fundamental...

Robustness of complex networks: Theory and application

Failures of networks, such as power outages in power systems, congestions in<br/>transportation networks, paralyse our daily life and introduce a tremendous cascading effect on our society. Networks should be constructed and operated in a robust way against random failures or deliberate attacks.<br/>We study how to add a single link into an...

On Robustness of Power Grids

Current and future trends in environmental, economical, and human-caused factors (such as power demand growth, over-ageing of assets in power grids, and extreme weather conditions) challenge power grid robustness in the near future, necessitating research to better analyse and understand the notion of robustness in power grids, and ultimately to...

Characterization and Design of Complex Networks

Modular Structures, Robustness and Protection of Complex Networks: Theory, Complexity and Algorithms

Community structure is observed in many real-world networks, such as (online) social networks, where groups of friends of a certain person are often also friends of each other. Newman's modularity has been explored as an important quantitative metric for communities and clusters detection in networks. We present a new expressions and bounds for...

Economic Complex Networks: A holarchy of evolving sector

This thesis aims to contribute to the understanding of the structure, composition, properties, functions and dynamics of economic systems. The research output results from joining advances in the scientific disciplines of systems theory, complex networks, Input-Output analysis and economic activity classification systems. The relevance of this...

Robustness and Optimization of Complex Networks: Reconstructability, Algorithms and Modeling

The infrastructure networks, including the Internet, telecommunication networks, electrical power grids, transportation networks (road, railway, waterway, and airway networks), gas networks and water networks, are becoming more and more complex. The complex infrastructure networks are crucial to our human society, and it has been a hot research ...

Characterization of complex networks: Application to robustness analysis

This thesis focuses on the topological characterization of complex networks. It specifically focuses on those elementary graph measures that are of interest when quantifying topology-related aspects of the robustness of complex networks. This thesis makes the following contributions to the field of complex networks. Firstly, the thesis analyses...

Random graphs: From static to dynamic

Many empirical studies on real-life networks show that many networks are small worlds, meaning that typical distances in these networks are small, and many of them have power-law degree sequences, meaning that the number of nodes with degree k falls off as kˆ (-τ) for some exponent τ>1. These networks are modeled by means of scale-free random...