Dynamic network analysis

Dynamic network analysis (DNA) is an emergent scientific field that brings together traditional social network analysis (SNA), link analysis (LA) and multi-agent systems (MAS) within network science and network theory. There are two aspects of this field. The first is the statistical analysis of DNA data. The second is the utilization of simulation to address issues of network dynamics. DNA networks vary from traditional social networks in that they are larger, dynamic, multi-mode, multi-plex networks, and may contain varying levels of uncertainty. The main difference of DNA to SNA is DNA taken the domain of time into account. One of the most notable and earliest case of the use of DNA is in Sampson's monastery study, where he took snapshots of the same network from different intervals and observed and analyzed the evolution of the network.

DNA statistical tools are generally optimized for large-scale networks and admit the analysis of multiple networks simultaneously in which, there are multiple types of nodes (multi-node) and multiple types of links (multi-plex). In contrast, SNA statistical tools focus on single or at most two mode data and facilitate the analysis of only one type of link at a time.

DNA statistical tools tend to provide more measures to the user, because they have measures that use data drawn from multiple networks simultaneously. From a computer simulation perspective, nodes in DNA are like atoms in quantum theory, nodes can be, though need not be, treated as probabilistic. Whereas nodes in a traditional SNA model are static, nodes in a DNA model have the ability to learn. Properties change over time; nodes can adapt: A company's employees can learn new skills and increase their value to the network; Or, capture one terrorist and three more are forced to improvise. Change propagates from one node to the next and so on. DNA adds the element of a network's evolution and considers the circumstances under which change is likely to occur.

There are three main features to dynamic network analysis that distinguish it from standard social network analysis. First rather than just using social networks, DNA research looking at meta-networks. Second, agent-based modeling and other forms of simulation are often used to explore how the networks evolve and change and the impact of interventions on those networks. Third, the links in the network are not binary; in fact, in many cases they represent the probability that there is a link.

Meta-Network A meta-network is a multi-mode, multi-link, multi-level network. Multi-mode means that there are many types of nodes; e.g., nodes people and locations. Multi-link means that there are many types of links; e.g., friendship and advice. Multi-level means that some nodes may be members of other nodes, such as a network composed of people and organizations and one of the links is who is a member of which organization.

While different researchers use different modes, common modes reflect who, what, when, where, why and how. A simple example of a meta-network is the PCANS formulation with people, tasks, and resources. A more detailed formulation considers people, tasks, resources, knowledge, and organizations.

Illustrative problems that people in the DNA area work on

 * Developing metrics and statistics to assess and identify change within and across networks.


 * Developing and validating simulations to study network change, evolution, adaptation, decay. See Computer simulation and organizational studies


 * Developing and testing theory of network change, evolution, adaptation, decay


 * Developing and validating formal models of network generation and evolution


 * Developing techniques to visualize network change overall or at the node or group level


 * Developing statistical techniques to see whether differences observed over time in networks are due to simply different samples from a distribution of links and nodes or changes over time in the underlying distribution of links and nodes


 * Developing control processes for networks over time


 * Developing algorithms to change distributions of links in networks over time


 * Developing algorithms to track groups in networks over time


 * Developing tools to extract or locate networks from various data sources such as texts


 * Developing statistically valid measurements on networks over time


 * Examining the robustness of network metrics under various types of missing data


 * Empirical studies of multi-mode multi-link multi-time period networks


 * Examining networks as probabilistic time-variant phenomena


 * Forecasting change in existing networks


 * Identifying trails through time given a sequence of networks


 * Identifying changes in node criticality given a sequence of networks anything else related to multi-mode multi-link multi-time period networks

Kathleen Carley, of Carnegie Mellon University, is a leading authority in this field.