The first thing you see in the room on your right as you enter Boston’s Museum of Science is a vertical peg board about 8 feet square. Sticking out of a checkerboard square pattern are pegs at the corner of every square. Ping-pong-size balls drop from the center top of the board and carom crazily off various pegs on the way down to the bottom. There is no way to predict which way a ball will zig or zag at each row or where any one ball will land in the bottom row. The pathway of each drop is completely random. Yet, despite the chaos at the beginning, the balls collect at the bottom in a perfect normal curve distribution. Within moments, the system changes from totally random individual actions to a completely symmetrical and predictable aggregate—order emerges out of chaos. Similar phenomena are exhibited by human social networks, like the complex web of traders and investors on the New York Stock Exchange (Bernstein, 1992) or the operation of any large city (Johnson, 2001; Watts, 2003). Why? Such is the mystery of self-organization in large, complex networks.
Similarly, what accounts for how birds flock and fish school? Why do accumulated grains of sand build to a mound or dune until finally one grain proves to be a grain too many and an avalanche occurs? And why do electrical systems crash when they reach comparable tipping points? Why are we all connected by the famous six degrees of separation? What do epidemics, earthquakes, computer viruses, religious fundamentalism, and the “Friends of Kevin Bacon” game all have in common?
The common element in the answers to these questions is that things are connected. Connections create networks, networks operate by rules and probably laws, and a new science of networks is emerging to determine and explain what these are. Nations, species, corporations, and armies will all be affected by this new science.
TV without the benefit of the fundamental knowledge of electromagnetic waves.
The engineering of complex physical networks, like that of the FCS, is not predictable because the scientific basis for constructing and evaluating such designs is immature. This is even more the case for characterizing, modeling, and evaluating modern criminal and terrorist networks that are built on a physical communications network infrastructure (Arquilla and Ronfeldt, 2001). The Office of Force Transformation (OFT) has advanced the concepts of network-centric warfare (Cebrowski and Garstka, 1998) and network-centric operations (Garstka and Alberts, 2004) to define warfare in the 21st century. Both concepts involve multiple interacting networks built one on top of the other. Neither has a firm empirical and analytical base. Thus, getting a grip on the fundamental science of networks—their structure and dynamics—is a topic of pressing concern for military as well as political and economic interests.
Recognizing the urgency of this situation, the National Research Council (NRC) Board on Army Science and Technology (BAST) formed the Committee on Network Science for Future Army Applications. The statement of task for the committee consists of four charges (Box 1-2). This document is the report of that committee.
Special care was devoted to the composition of the committee. Biographies are given in Appendix A. Three representative groups of members were selected. The first group included individuals from the physical sciences, engineering, biological sciences, and social sciences research communities. In order to sample the breadth of intellectual effort on network science, committee members were selected who have recent first-hand experience in the subject matter as reflected in their recent books or research and teaching assignments. Thus, committee membership includes the authors of Six Degrees: The Science of the Connected Age
The Assistant Secretary of the Army (Acquisition, Logistics, and Technology) has requested the National Research Council (NRC) Board on Army Science and Technology (BAST) conduct a study to define the field of Network Science. The NRC will: