Volkan Ustun

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The successful practice of simulation requires a number of capabilities; two key capabilities are creating a conceptual model of the system to be simulated, and translating the conceptual model to a computational process or simulation program. We describe how OMG's new graphical systems modeling language, OMG SysML#8482; (OMG 2009), can be used to create a(More)
The aim of this paper is twofold: First, to propose a data model that enables the user to model a physical facility at different levels of detail and explicitly incorporate interactions among the components of the facility. Second to suggest a methodology for line-of-sight, which is the primary factor in recognition of threats in physical security settings.
Recently reported results with distributed-vector word representations in natural language processing make them appealing for incorporation into a general cognitive architecture like Sigma. This paper describes a new algorithm for learning such word representations from large, shallow information resources, and how this algorithm can be implemented via(More)
Symbolic architectures are effective at complex cognitive reasoning, but typically are incapable of important forms of sub-cognitive processing – such as perception – without distinct modules connected to them via low-bandwidth interfaces. Neural architectures, in contrast, may be quite effective at the latter, but typically struggle with the former. Sigma(More)
Mental simulation is proposed by cognitive psychologists as a candidate to model the human reasoning process. In this paper, we propose a methodology that models mental simulation to create realistic human behavior in simulated environments. This methodology is used to generate realistic intruder and guard behavior in physical security systems simulation.(More)
Modeling and simulation of physical security systems involves designing and analyzing security systems, protocols, and policies that aim to protect fixed-site facilities against intrusions by external threats, as well as unauthorized acts by insiders. Realistic and credible simulations of such systems require incorporation of human behavior models along(More)
Human cognition runs at ~50 msec per cognitive cycle, implying that any biologically inspired cognitive architecture that strives for real-time performance needs to be able to run at this speed. Sigma is a cognitive architecture built upon graphical models – a broadly applicable state-of-the-art formalism for implementing cognitive capabilities – that are(More)