text: The investigation of the terrorist attack is a time-critical task. The investigators have a limited time window to diagnose the organizational background of the terrorists, to run down and arrest the wire-pullers, and to take an action to prevent or eradicate the terrorist attack. The intuitive interface to visualize the intelligence data set stimulates the investigators’ experience and knowledge, and aids them in decision-making for an immediately effective action. This paper presents a computational method to analyze the intelligence data set on the collective actions of the perpetrators of the attack, and to visualize it into the form of a social network diagram which predicts the positions where the wire-pullers conceals themselves.
  @cite_21: This paper looks at the difficulty in mapping covert networks. Analyzing networks after an event is fairly easy for prosecution purposes. Mapping covert networks to prevent criminal activity is much more difficult. We examine the network surrounding the tragic events of September 11th, 2001. Through public data we are able to map a portion of the network centered around the 19 dead hijackers. This map gives us some insight into the terrorist organization, yet it is incomplete. Suggestions for further work and research are offered.
  @cite_3: A consistent trade-off facing participants in any criminal network is that between organizing for efficiency or security—participants collectively pursue an objective while keeping the action leading to that goal concealed. Which side of the trade-off is prioritized depends on the objective that is pursued by the criminal group. The distinction is most salient when comparing terrorist with criminal enterprise networks. Terrorist networks are ideologically driven, while criminal enterprises pursue monetary ends. Time-to-task is shorter in the criminal enterprise and group efficiency is therefore prioritized over group security. Terrorist networks, in contrast, have longer horizons and security is prioritized over the execution of any single attack. Using Krebs’ exploratory research on networks of terrorist cells and electronic surveillance transcripts of a drug importation network, our analyses demonstrate how these opposing trade-offs emerge in criminal group structures.
  @cite_19: Preface 1. The Origins of the Jihad 2. The Evolution of the Jihad 3. The Mujahedin 4. Joining the Jihad 5. Social Networks and the Jihad Conclusion Appendix: Names of Terrorists Glossary of Foreign-Language Terms Bibliography Index
  @cite_20: We investigate the structures present in the Enron email dataset using singular value decomposition and semidiscrete decomposition. Using word frequency profiles, we show that messages fall into two distinct groups, whose extrema are characterized by short messages and rare words versus long messages and common words. It is surprising that length of message and word use pattern should be related in this way. We also investigate relationships among individuals based on their patterns of word use in email. We show that word use is correlated to function within the organization, as expected. Lastly, we show that relative changes to individuals' word usage over time can be used to identify key players in major company events.
  @cite_12: 
  @cite_17: Acknowledgements 1. Introduction Stanley Wasserman, John Scott and Peter J. Carrington 2. Recent developments in network measurement Peter V. Marsden 3. Network sampling and model fitting Ove Frank 4. Extending centrality Martin Everett and Stephen P. Borgatti 5. Positional analyses of sociometric data Patrick Doreian, Vladimir Batagelj and Anuska Ferligoj 6. Network models and methods for studying the diffusion of innovations Thomas W. Valente 7. Using correspondence analysis for joint displays of affiliation networks Katherine Faust 8. An introduction to random graphs, dependence graphs, and p* Stanley Wasserman and Garry Robins 9. Random graph models for social networks: multiple relations or multiple raters Laura M. Koehly and Philippa Pattison 10. Interdependencies and social processes: dependence graphs and generalized dependence structures Garry Robins and Philippa Pattison 11. Models for longitudinal network data Tom A. B. Snijders 12. Graphical techniques for exploring social network data Linton C. Freeman 13. Software for social network analysis Mark Huisman and Marijtje A. J. van Duijn Index.
summary: Social network analysis @cite_17 is a study of social structures, which are made of nodes (individuals, organizations etc.), which are linked by one or more specific types of relationship (transmission of influence, presence of trust etc.). Terrorist or criminal organizations have been studied empirically @cite_19 . Factor analysis is applied to study email exchange in Enron, which ended in bankruptcy due to the institutionalized accounting fraud @cite_20 . The criminal organizations tend to be strings of inter-linked small groups that lack a central leader, but to coordinate their activities along logistic trails and through bonds of friends. Hypothesis can be built by paying attention to remarkable white spots and hard-to-fill positions in a network @cite_12 . The conspirators in the 9 11 terrorist organization are relevant in reducing the distance between hijackers, and enhancing communication efficiently @cite_21 . The 9 11 terrorists' social network is investigated from the viewpoint of efficiency and security trade-off @cite_3 . More security-oriented structure arises from longer time-to-task of the terrorists' objectives. The conspirators improve communication efficiency, preserving hijackers' small visibility and exposure.