The capabilities and quality of existing models of government and commercial operations need to be assessed. New models may have to be built and validated in some areas. The results of these efforts, together with new methods, some of which may have to be developed, should be used to construct integrated models that can improve our understanding of the vulnerabilities of the infrastructures and their interdependencies, i.e., what needs to be defended. This understanding can be used in turn to develop sensor deployment and defensive strategies, the merit of which can be indicated by the model and validated by red-team efforts of the type described in Recommendation 10.2.

Recommendation 10.4: The federal government, working with the various commercial organizations that have been identified with homeland-security-related missions, should identify counterterrorism-related databases and establish metadata standards and assess tools for integrating diverse bits of data.

To conduct the analyses on which models are based, a rational data structure is needed. Efforts toward achieving this structure are under way in some government organizations. These efforts, however, have pointed to the need for additional funding, some for the organizations operating the various databases in order to establish the necessary metadata standards, and some to develop access tools for database interoperation.


The preceding sections have emphasized the critical importance of models in the systems approach to counterterrorism, and they have also noted some of the deficiencies of current modeling technologies. This section describes two methods of model development and operation that appear to offer significant potential for analyzing the complexities of counterterrorism applications. As such, they should be a significant part of the research agenda.

Complex Adaptive Systems and Agent-Based Models

Complex adaptive systems involve phenomena that may be characterized by the interactions of numerous individual agents or elements, which tend to self-organize at increasingly higher levels. This process results in evolutionary, emergent, and adaptive properties that are not exhibited by the individual agents themselves. For example, an animal may be an agent in a formation of a herd of animals, and herds of animals may become a species, and the species may be part of a particular ecosystem. There is a clear analogy here to the characteristics of our society’s critical infrastructure and its associated adaptation, emergence, and evolution.

Complex adaptive systems obtain data and information from their internal

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