Agents in Argonne’s Electricity Market Complex Adaptive System (EMCAS) model.

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CASS turns simulation upside down

Turning the traditional simulation world upside down, Argonne scientists and engineers are designing new computer simulations from the bottom up to model everything from electric power deregulation to endangered species habitats to ancient civilizations.

Argonne has one of the country’s leading research groups in the burgeoning world of modeling complex adaptive systems simulation (CASS).

This programming approach allows researchers to examine the behavior and interactions of individual agents—a single decision-making entity such as a consumer, company or product—within a larger system. Complex systems such as traffic and stock markets involve multiple variables and individual decision makers, each with his or her own goals and strategies.

“We simulate the process of agents interacting,” said Charles Macal, group leader for modeling, simulation and visualization in Argonne’s Decision and Information Sciences Division (DIS), “instead of solving equations based on long-run average behavior.”

CASS takes advantage of today’s greater computer power and new software tools, but it also represents a change in perspective.

“Most computer modeling looks at the aggregate—the big picture—and examines averages,” said software engineer Mike North of the DIS Division. “Agent-based simulation builds models up from the individual level and looks at the patterns of behavior that emerge or the presence of extreme events. Using individual building blocks is like understanding chemistry by looking at atoms and molecules instead of a solid lump of coal.”

“Building the simulations from the bottom up,” Macal said, “allows interactions between the agents to determine the system’s primary behavior. The agent interactions create patterns and structures we would not anticipate from looking at the simple components. This technique is particularly useful in simulating the behavior of agents that adapt to changing conditions.”

Argonne researchers are creating CASS software, developing new applications, using it in their research and educating others about this powerful new tool.

Working with the University of Chicago, Argonne is extending and improving the university’s CASS software, called RePast. North and other programmers are writing software for the Java-based modeling-program that runs on anything from a PC to a supercomputer.

CASS allows researchers to improve their model’s realism by creating a closer match with the real world.

As a leader in the CASS community, Argonne has been sponsoring simulation courses and workshops annually since 1999. In conjunction with the University of Chicago and Sante Fe Institute, Argonne created a week-long, agent-based simulation course for industry and government software designers in defense, transportation and communications.

Electric power modeling
For the Illinois Commerce Commission (ICC), the DIS Division is studying electric power deregulation using the Argonne-created Electricity Market Complex Adaptive System (EMCAS) model. This effort builds on the laboratory’s more than three decades of experience in electric power industry modeling and market transactions.

To avoid many of the mistakes California experienced in its electric power deregulation, Argonne is simulating problems that could arise as Illinois deregulates its electric power industry. Argonne simulations will help the ICC to understand the potential effects of the deregulation process, which must be implemented by January 2005. The findings could range from identifying the need to build new power lines to determining possible market conditions that could affect electricity prices.

The Decision and Information Sciences Division is modeling the system from the ground up using such agents as:

• brokers,
• generators,
• major power lines,
• generation companies,
• regulatory agencies,
• residential, industrial and commercial consumers,
• demand companies that sell to consumers, and
• random events caused by weather or outages.

The Argonne simulation will probe the system for power outages, market manipulation or other behavior outside of the norm. The University of Illinois at Urbana-Champaign’s detailed model of the physical power grid is an important component of this electricity research.

Argonne researchers are also using CASS for:

• developing counter-drug simulations for the U.S. Joint Chief of Staffs to combat the South American cocaine trade.
• aiding military land managers working to re-establish the endangered Red-Cockaded Woodpecker population.
• creating an ancient Mesopotamian village with the University of Chicago’s Oriental Institute to understand sustainability under environmental stress.
• exploring terrorist-network modeling for homeland security. The scenarios the CASS software develops go beyond what researchers can imagine and provide insight for homeland security decision making and training.

For more information, please contact Evelyn Brown.

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