Goal-Driven Autonomy for Cognitive Systems
Goal-Driven Autonomy for Cognitive Systems
复制标题
认知系统的目标驱动自主性
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发表时间:
2014
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通讯作者:
D. Perlis
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作者:
Matthew Paisner;Michael T. Cox;Michael Maynord;D. Perlis
Goal-Driven Autonomy for Cognitive Systems Matt Paisner (mpaisner@umd.edu) Michael T. Cox (mcox@cs.umd.edu) Michael Maynord (maynord@umd.edu) Don Perlis (perlis@cs.umd.edu) Computer Science Department, A.V. Williams Bldg. College Park, MD 20742 USA Abstract Complex, dynamic environments present special challenges to autonomous agents. Specifically, agents have difficulty when the world does not cooperate with design assumptions. We present an approach to autonomy that seeks to maximize robustness rather than optimality on a specific task. Goal- driven autonomy involves recognizing possibly new problems, explaining what causes the problems and generating goals to solve the problems. We present such a model within the MIDCA cognitive architecture and show that under certain conditions this model outperforms a less flexible approach to handling unexpected events. Keywords: goal generation; anomaly handling; interpretation and explanation; TF-Tree; cognitive architecture; intelligent autonomy. Introduction Humans are astonishingly versatile, dealing with a wide range of unanticipated circumstances while still making headway on high-level goals. Humans can also recognize new problems and opportunities when they arise and react appropriately to them. Yet for the most part our machines cannot; they are like idiot-savants, very good at one narrow task and useless for anything else, even tasks very similar to the one they were designed for. This is the so-called brittleness problem, a major stumbling block for AI. What we appear to need is the opposite of expert systems: machines that might not excel at anything, but that can muddle through a wide range of circumstances and keep a strategic perspective. Yet more than 50 years of intense effort has failed to produce such machines. One approach to the problem of brittleness uses what we call goal-driven autonomy in a cognitive architecture. Here we describe some benefits of this approach in dynamic environments. Goal-Driven Autonomy (GDA) is a unique conception that gives full independence to autonomous agents (Cox, 2007; Klenk, Molineaux, & Aha, 2013; Munoz-Avila, Jaidee, Aha, Carter, 2010). Rather than arbitrary anomaly-detection, the agent searches for problems in the context of its current goals and mission. Not all anomalies are problems, nor are all problems important enough to attend to. Rather than general assessment of an entire world state, the agent should abductively explain the causal factors giving rise to the problem. Given an explanation, a GDA agent may generate a (possibly new) goal that solves the problem (e.g., by removing its supporting conditions). In these terms, GDA is as much about problem recognition as it is problem-solving (Cox, 2013). Consider a fire that breaks out at a construction site. This is a problem in many ways, not the least of which is that preconditions for actions (e.g., the integrity of building materials) will become unsatisfied. A standard planning algorithm might therefore generate a subgoal to extinguish the fire so that construction can continue. However a subsequent fire in quick succession might justify an investigation into a long-term threat to the construction site. One possible explanation would be the presence of an arsonist, leading to the goal of having the perpetrator in jail. Hence a direct reactive approach to fires would be to put them out; a GDA approach to this same situation would recognize the underlying problem in terms of its threat to the future of the enterprise. This paper will examine the distinction between such approaches to intelligent reasoning and behavior in a metacognitive architecture called MIDCA and will report the results of a simple empirical study to evaluate these differences. In section 2, we present the MIDCA architecture containing an implemented instantiation of the GDA model. In section 3 we evaluate the performance of systems making use of three distinct goal generation methods: exogenous goals; statistically generated goals; goals produced by a knowledge rich explanation system. Section 4 presents an overview of future work, section 5 surveys related work, and section 6 concludes. Goal-Driven Autonomy in a Cognitive Architecture The Metacognitive, Integrated, Dual-Cycle Architecture (MIDCA) (Cox, Maynord, Paisner, Perlis, & Oates, 2013) consists of “action-perception” cycles at both the cognitive (i.e., object) level and the metacognitive (i.e., meta-) level. Figure 1 shows the implemented components of the object level with the meta-level abstracted. The output side of each cycle consists of intention, planning, and action execution, whereas the input side consists of perception, interpretation, and goal evaluation. A cycle selects a goal and commits to achieving it. The agent then creates a plan to achieve the goal and subsequently executes the planned actions to make the domain match the goal state. The agent perceives changes to the environment resulting from the actions, interprets the percepts with respect to the plan, and evaluates the interpretation with respect to the goal. At the