Steve Brophy’s research while affiliated with Concordia University Ann Arbor and other places

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Publications (6)


Characterizing and Predicting Agents via Multi-Agent Evolution
  • Article

January 2011

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14 Reads

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5 Citations

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S. Brueckner

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R. Matthews

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[...]

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S. Brophy

Swarming Pattern Analysis to Identify IED Threat

September 2010

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54 Reads

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2 Citations

At a tactical level, insurgents planning attacks with Improvised Explosive Devices (IEDs) are constrained in their choice of target by the specific location of their safe house or weapons cache, the geographic context in which they operate, and the pattern of potential targets as it presents itself at a given time. Geographic profiling in law-enforcement already takes advantage of similar constraints to identify possible origin locations of serial offenders. We show how geographic profiling of past IED events can significantly enhance our ability to identify areas at risk for future attacks. Specifically, we introduce three tightly coupled swarming pattern analysis models (profiling, clustering, forecasting) that refine each others' conclusions dynamically and point to systematic evaluation experiments that confirm the research hypothesis.


Figure 1: Tracking a nonlinear dynamical system. a = system state space; b = system trajectory over time; c = recent measurements of system state; d = short-range prediction.
Figure 3: Behavioral Emulation and Extrapolation. Each avatar generates a stream of ghosts that sample the personality space of its entity. They evolve against the entity's recent observed behavior, and the fittest ghosts run into the future to generate predictions.
Figure 4: Delta Disposition for a Chicken’s Ghosts. 
Figure 5: Delta Disposition for a Rambo. 
Real-time agent characterization and prediction
  • Conference Paper
  • Full-text available

May 2007

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207 Reads

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28 Citations

Reasoning about agents that we observe in the world is challenging. Our available information is often limited to observations of the agent's external behavior in the past and present. To understand these actions, we need to deduce the agent's internal state, which includes not only rational elements (such as intentions and plans), but also emotive ones (such as fear). In addition, we often want to predict the agent's future actions, which are constrained not only by these inward characteristics, but also by the dynamics of the agent's interaction with its environment. BEE (Behavior Evolution and Extrapolation) uses a faster-than-real-time agent-based model of the environment to characterize agents' internal state by evolution against observed behavior, and then predict their future behavior, taking into account the dynamics of their interaction with the environment.

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Figure 1: Tracking a nonlinear dynamical system. a = system state space; b = system trajectory over time; c = recent measurements of system state; d = short-range prediction. 
Figure 3: Behavioral Emulation and Extrapolation. Each avatar generates a stream of ghosts that sample the personality space of its entity. They evolve against the entity's recent observed behavior, and the fittest ghosts run into the future to generate predictions. 
Figure 4: Delta Disposition for a Chicken's Ghosts. 
Figure 5: Delta Disposition for a Rambo. 
Real-Time Evolutionary Agent Characterization and Prediction

April 2007

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119 Reads

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10 Citations

Reasoning about agents that we observe in the world is challeng-ing. Our available information is often limited to observations of the agent's external behavior in the past and present. To under-stand these actions, we need to deduce the agent's internal state, which includes not only rational elements (such as intentions and plans), but also emotive ones (such as fear). In addition, we often want to predict the agent's future actions, which are constrained not only by these inward characteristics, but also by the dynamics of the agent's interaction with its environment. BEE (Behavior Evolution and Extrapolation) uses a faster-than-real-time agent-based model of the environment to characterize agents' internal state by evolution against observed behavior, and then predict their future behavior, taking into account the dynamics of their interaction with the environment.


Comparing Agent Trajectories

January 2007

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17 Reads

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1 Citation

Sometimes it is desirable to measure the difference between the spatial trajectories of two or more agents. The naïve measure (the sum of Euclidean distances between locations at successive timesteps) increases with the lengths of the trajectories, which is not suitable for some applications. This paper explains the problem that motivates such a comparison, describes the design of the comparison that we are using, and gives an example of its ap-plication.


Figure 1: Tracking a nonlinear dynamical system. a = system state space; b = system trajectory over time; c = recent measurements of system state; d = short-range prediction.
Figure 4: BEE vs. Human.—BEE can detect chickens sooner than human observers.  
Figure 5: Predictive accuracy.—Each point is the average of prediction errors for all Red units, measured in 10-meter cells. Black points are BEE, stemmed points are LG, grey points are LG interpolated.  
Evolving Agents to Recognize Plans and Emotions

January 2006

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68 Reads

Reasoning about agents that we observe in the world is challenging. Our available information is often limited to observations of the agent's external behavior. To under-stand these actions, we need to deduce the agent's internal state, which includes not only rational elements (such as in-tentions and plans), but also emotive ones (such as fear). In addition, we often want to predict the agent's future actions, which are constrained not only by these inward characteris-tics, but also by the dynamics of the agent's interaction with its environment. BEE (Behavior Evolution and Extrapola-tion) uses a faster-than-real-time agent-based model of the environment to characterize agents' internal state by evolu-tion against observed behavior, and then predict their future behavior, taking into account the dynamics of their interac-tion with the environment.

Citations (4)


... For example, a method for predicting the behavior of software agents could be an interesting issue to be added to MAS-Scout. In this regard, the patent US7,921,066 titled "Characterizing and predicting agents via multi-agent evolution" [23] can help. By employing a set of parameters that govern the behavior of the agents, this invention estimates the internal state of at least one of the agents by its behavior in the simulation, including its movement within the environment. ...

Reference:

Self-Organizing Multi-Agent Systems by means of Scout Movement
Characterizing and Predicting Agents via Multi-Agent Evolution
  • Citing Article
  • January 2011

... As the enemy takes actions and moves about the battlefield, a pheromone-analogy algorithm fits these current behaviors to past behaviors and prunes and clarifies its model of the mental state of the enemy. Finally, this sub-component projects future " broadbrush " physical behaviors and mental state evolution by exploring multiple potential roll-outs of actions and events using a concept of ghost agents or avatars [4,5,6,7,8]. Figure 4illustrates a few of the predictions made by this sub-component of the ARM. Predictions of emotional states were displayed as 'alerts' as they were identified. ...

Real-Time Evolutionary Agent Characterization and Prediction

... Secondly, at Section 5.2 on page 9, we introduced the notion of magnitude as a property of each observable entity in the domain, to represent an observation's memorability. With these in hand, our model adopts a conventional implementation of decay (familiar from work such as (Van Dyke Parunak et al., 2007) involving pheromones). ...

Real-time agent characterization and prediction

... Based on a logical probabilistic method on a collection of security properties which consider the details of botnet attacks, a method to identify and act against the negative impacts of a botnet using estimates of the risks of botnet attacks exist for any object-risk business network [85]. Study [86] demonstrates how three closely joined swarming pattern analysis designs including profiling, clustering, and forecasting improve each other's results greatly. It also indicates that systematic assessment experiments approve the research hypothesis [86]. ...

Swarming Pattern Analysis to Identify IED Threat
  • Citing Conference Paper
  • September 2010