Publications

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Transnational Islamic activism and radicalization : patterns, trends, and prognosticators

Colbaugh, Richard C.; Engi, Dennis E.; Laviolette, Randall A.; Spomer, Judith E.

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Final report : impacts analysis for cyber attack on electric power systems (national SCADA test bed FY09)

Stamp, Jason E.; Laviolette, Randall A.

The development continues for Finite State Abstraction (FSA) methods to enable Impacts Analysis (IA) for cyber attack against power grid control systems. Building upon previous work, we successfully demonstrated the addition of Bounded Model Checking (BMC) to the FSA method, which constrains grid conditions to reasonable behavior. The new FSA feature was successfully implemented and tested. FSA is an important part of IA for the power grid, complementing steady-state approaches. It enables the simultaneous evaluation of myriad dynamic trajectories for the system, which in turn facilitates IA for whole ranges of system conditions simultaneously. Given the potentially wide range and subtle nature of potential control system attacks, this is a promising research approach. In this report, we will explain the addition of BMC to the previous FSA work and some testing/simulation upon the implemented code using a two-bus test system. The current FSA approach and code allow the calculation of the acceptability of power grid conditions post-cyber attack (over a given time horizon and for a specific grid topology). Future work will enable analysis spanning various topologies (to account for switching events), as well as an understanding of the cyber attack stimuli that can lead to undesirable grid conditions.

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LDRD final report : massive multithreading applied to national infrastructure and informatics

Barrett, Brian B.; Hendrickson, Bruce A.; Laviolette, Randall A.; Leung, Vitus J.; Mackey, Greg; Murphy, Richard C.; Phillips, Cynthia A.; Pinar, Ali P.

Large relational datasets such as national-scale social networks and power grids present different computational challenges than do physical simulations. Sandia's distributed-memory supercomputers are well suited for solving problems concerning the latter, but not the former. The reason is that problems such as pattern recognition and knowledge discovery on large networks are dominated by memory latency and not by computation. Furthermore, most memory requests in these applications are very small, and when the datasets are large, most requests miss the cache. The result is extremely low utilization. We are unlikely to be able to grow out of this problem with conventional architectures. As the power density of microprocessors has approached that of a nuclear reactor in the past two years, we have seen a leveling of Moores Law. Building larger and larger microprocessor-based supercomputers is not a solution for informatics and network infrastructure problems since the additional processors are utilized to only a tiny fraction of their capacity. An alternative solution is to use the paradigm of massive multithreading with a large shared memory. There is only one instance of this paradigm today: the Cray MTA-2. The proposal team has unique experience with and access to this machine. The XMT, which is now being delivered, is a Red Storm machine with up to 8192 multithreaded 'Threadstorm' processors and 128 TB of shared memory. For many years, the XMT will be the only way to address very large graph problems efficiently, and future generations of supercomputers will include multithreaded processors. Roughly 10 MTA processor can process a simple short paths problem in the time taken by the Gordon Bell Prize-nominated distributed memory code on 32,000 processors of Blue Gene/Light. We have developed algorithms and open-source software for the XMT, and have modified that software to run some of these algorithms on other multithreaded platforms such as the Sun Niagara and Opteron multi-core chips.

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Final report : impacts analysis for cyber attack on electric power systems (National SCADA Test Bed FY08)

Stamp, Jason E.; Laviolette, Randall A.; Richardson, Bryan T.

To analyze the risks due to cyber attack against control systems used in the United States electrical infrastructure, new algorithms are needed to determine the possible impacts. This research is studying the Reliability Impact of Cyber ttack (RICA) in a two-pronged approach. First, malevolent cyber actions are analyzed in terms of reduced grid reliability. Second, power system impacts are investigated using an abstraction of the grid's dynamic model. This second year of esearch extends the work done during the first year.

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Tolerating the community detection resolution limit with edge weighting

Proposed for publication in the Proceedings of the National Academy of Sciences.

Hendrickson, Bruce A.; Laviolette, Randall A.; Phillips, Cynthia A.; Berry, Jonathan W.

Communities of vertices within a giant network such as the World-Wide-Web are likely to be vastly smaller than the network itself. However, Fortunato and Barthelemy have proved that modularity maximization algorithms for community detection may fail to resolve communities with fewer than {radical} L/2 edges, where L is the number of edges in the entire network. This resolution limit leads modularity maximization algorithms to have notoriously poor accuracy on many real networks. Fortunato and Barthelemy's argument can be extended to networks with weighted edges as well, and we derive this corollary argument. We conclude that weighted modularity algorithms may fail to resolve communities with fewer than {radical} W{epsilon}/2 total edge weight, where W is the total edge weight in the network and {epsilon} is the maximum weight of an inter-community edge. If {epsilon} is small, then small communities can be resolved. Given a weighted or unweighted network, we describe how to derive new edge weights in order to achieve a low {epsilon}, we modify the 'CNM' community detection algorithm to maximize weighted modularity, and show that the resulting algorithm has greatly improved accuracy. In experiments with an emerging community standard benchmark, we find that our simple CNM variant is competitive with the most accurate community detection methods yet proposed.

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Towards risk-based management of critical infrastructures : enabling insights and analysis methodologies from a focused study of the bulk power grid

Laviolette, Randall A.; Richardson, Bryan T.; Cook, Benjamin K.

This report summarizes research on a holistic analysis framework to assess and manage risks in complex infrastructures, with a specific focus on the bulk electric power grid (grid). A comprehensive model of the grid is described that can approximate the coupled dynamics of its physical, control, and market components. New realism is achieved in a power simulator extended to include relevant control features such as relays. The simulator was applied to understand failure mechanisms in the grid. Results suggest that the implementation of simple controls might significantly alter the distribution of cascade failures in power systems. The absence of cascade failures in our results raises questions about the underlying failure mechanisms responsible for widespread outages, and specifically whether these outages are due to a system effect or large-scale component degradation. Finally, a new agent-based market model for bilateral trades in the short-term bulk power market is presented and compared against industry observations.

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8 Results
8 Results