Posts Tagged ‘meta-reasoning’
28
Sep
Posted by cognitivecomputing in Agents, Game AI, Learning, Talks, Web / Web 2.0. Tagged: believable agents, case-based reasoning, games, interactive drama, meta-reasoning, multistrategy learning, planning, problem solving, real-time cbr, rts games, virtual worlds. 3 comments
User-generated content is everywhere: photos, videos, news, blogs, art, music, and every other type of digital media on the Social Web. Games are no exception. From strategy games to immersive virtual worlds, game players are increasingly engaged in creating and sharing nearly all aspects of the gaming experience: maps, quests, artifacts, avatars, clothing, even games themselves. Yet, there is one aspect of computer games that is not created and shared by game players: the AI. Building sophisticated personalities, behaviors, and strategies requires expertise in both AI and programming, and remains outside the purview of the end user.
To understand why Game AI is hard, we need to understand how it works. AI can take digital entertainment beyond scripted interactions into the arena of truly interactive systems that are responsive, adaptive, and intelligent. I discuss examples of AI techniques for character-level AI (in embedded NPCs, for example) and game-level AI (in the drama manager, for example). These types of AI enhance the player experience in different ways. The techniques are complicated and are usually implemented by expert game designers.
I argue that User-Generated AI is the next big frontier in the rapidly growing Social Gaming area. From Sims to Risk to World of Warcraft, end users want to create, modify, and share not only the appearance but the “minds” of their characters. I present my recent research on intelligent technologies to assist Game AI authors, and show the first Web 2.0 application that allows average users to create AIs and challenge their friends to play them—without programming. I conclude with some thoughts about the future of AI-based Interactive Digital Entertainment.
CMU Robotics & Intelligence Seminar, September 28, 2009
Carnegie-Mellon University, Pittsburgh, PA.
MIT Media Lab Colloquium, January 25, 2010
Massachusetts Institute of Technology, Cambridge, MA.
Stanford Media X Philips Seminar, February 1, 2010
Stanford University, Stanford, CA.
Pixar Research Seminar, February 2, 2010
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9
Sep
Posted by cognitivecomputing in Game AI, Learning. Tagged: believable agents, games, goal-driven learning, meta-reasoning, planning, real-time cbr, virtual worlds. Leave a comment
Intelligent agents working in real-time domains need to adapt to changing circumstance so that they can improve their performance and avoid their mistakes. AI agents designed for interactive games, however, typically lack this ability. Game agents are traditionally implemented using static, hand-authored behaviors or scripts that are brittle to changing world dynamics and cause a break in player experience when they repeatedly fail. Furthermore, their static nature causes a lot of effort for the game designers as they have to think of all imaginable circumstances that can be encountered by the agent. The problem is exacerbated as state-of-the-art computer games have huge decision spaces, interactive user input, and real-time performance that make the problem of creating AI approaches for these domains harder.
In this paper we address the issue of non-adaptivity of game playing agents in complex real-time domains. The agents carry out run-time adaptation of their behavior sets by monitoring and reasoning about their behavior execution to dynamically carry out revisions on the behaviors. The behavior adaptation approaches has been instantiated in two real-time interactive game domains. The evaluation results shows that the agents in the two domains successfully adapt themselves by revising their behavior sets appropriately.
Read the paper:
Run-Time Behavior Adaptation for Real-Time Interactive Games
by Manish Mehta, Ashwin Ram
IEEE Transactions on Computational Intelligence and AI in Games, Vol. 1, No. 3, September 2009
www.cc.gatech.edu/faculty/ashwin/papers/er-09-09.pdf
22
Jul
Posted by cognitivecomputing in Game AI, Learning. Tagged: case-based reasoning, games, meta-reasoning, planning, real-time cbr, rts games. 1 comment
Case-based planning (CBP) systems are based on the idea of reusing past successful plans for solving new problems. Previous research has shown the ability of meta-reasoning approaches to improve the performance of CBP systems. In this paper we present a new meta-reasoning approach for autonomously improving the performance of CBP systems that operate in real-time domains.
Our approach uses failure patterns to detect anomalous behaviors, and it can learn from experience which of the failures detected are important enough to be fixed. Finally, our meta-reasoning approach can exploit both successful and failed executions for meta-reasoning.
We illustrate its benefits with experimental results from a system implementing our approach called Meta-Darmok in a real-time strategy game. The evaluation of Meta-Darmok shows that the system successfully adapts itself and its performance improves through appropriate revision of the case base.
Read the paper:
Using Meta-Reasoning to Improve the Performance of Case-Based Planning
by Manish Mehta, Santi Ontañón, Ashwin Ram
International Conference on Case-Based Reasoning (ICCBR-09), Seattle, July 2009
www.cc.gatech.edu/faculty/ashwin/papers/er-09-06.pdf
16
Jul
Posted by cognitivecomputing in Learning. Tagged: case-based reasoning, meta-reasoning, multistrategy learning, problem solving. Leave a comment
In this paper we describe the application of a novel learning and problem solving architecture to the domain of airspace management, where multiple requests for the use of airspace need to be reconciled and managed automatically. The key feature of our “Generalized Integrated Learning Architecture” (GILA) is a set of integrated learning and reasoning (ILR) systems coordinated by a central meta-reasoning executive (MRE). Each ILR learns independently from the same training example and contributes to problem-solving in concert with other ILRs as directed by the MRE. Formal evaluations show that our system performs as well as or better than humans after learning from the same training data. Further, GILA outperforms any individual ILR run in isolation, thus demonstrating the power of the ensemble architecture for learning and problem solving.
Read the paper:
An Ensemble Learning and Problem Solving Architecture for Airspace Management
by XS Zhang et al.
International Conference on Innovative Applications of Artificial Intelligence (IAAI-09), Pasadena, CA, July 2009
www.cc.gatech.edu/faculty/ashwin/papers/er-09-03.pdf
15
Jul
Posted by cognitivecomputing in Learning. Tagged: goal-driven learning, meta-reasoning, multistrategy learning, problem solving. Leave a comment
Goal Driven Learning (GDL) focuses on systems that determine by themselves what has to be learned and how to learn it. Typically GDL systems use meta-reasoning capabilities over a base reasoner, identifying learning goals and devising strategies. In this paper we present a novel GDL technique to deal with complex AI systems where the meta-reasoning module has to analyze the reasoning trace of multiple components with potentially different learning paradigms. Our approach works by distributing the generation of learning strategies among the different modules instead of centralizing it in the meta-reasoner. We implemented our technique in the GILA system, that works in the airspace task orders domain, showing an increase in performance.
Read the paper:
Goal-Driven Learning in the GILA Integrated Intelligence Architecture
by Jai Radhakrishnan, Santi Ontañón, Ashwin Ram
International Joint Conference on Artificial Intelligence (IJCAI-09), Pasadena, CA, July 2009
www.cc.gatech.edu/faculty/ashwin/papers/er-09-02.pdf
22
May
Posted by cognitivecomputing in Agents, Learning, Robotics. Tagged: believable agents, case-based reasoning, interactive drama, meta-reasoning, virtual worlds. 1 comment
Believable agents designed for long-term interaction with human users need to adapt to them in a way which appears emotionally plausible while maintaining a consistent personality. For short-term interactions in restricted environments, scripting and state machine techniques can create agents with emotion and personality, but these methods are labor intensive, hard to extend, and brittle in new environments. Fortunately, research in memory, emotion and personality in humans and animals points to a solution to this problem. Emotions focus an animal’s attention on things it needs to care about, and strong emotions trigger enhanced formation of memory, enabling the animal to adapt its emotional response to the objects and situations in its environment. In humans this process becomes reflective: emotional stress or frustration can trigger re-evaluating past behavior with respect to personal standards, which in turn can lead to setting new strategies or goals.
To aid the authoring of adaptive agents, we present an artificial intelligence model inspired by these psychological results in which an emotion model triggers case-based emotional preference learning and behavioral adaptation guided by personality models. Our tests of this model on robot pets and embodied characters show that emotional adaptation can extend the range and increase the behavioral sophistication of an agent without the need for authoring additional hand-crafted behaviors.
Read the paper:
Emotional Memory and Adaptive Personalities
by Anthony Francis, Manish Mehta, Ashwin Ram
Handbook of Research on Synthetic Emotions and Sociable Robotics: New Applications in Affective Computing and Artificial Intelligence, IGI Global, 2009
www.cc.gatech.edu/faculty/ashwin/papers/er-08-10.pdf
23
Oct
Posted by cognitivecomputing in Game AI, Learning. Tagged: games, meta-reasoning, rts games. Leave a comment
Behavior authoring for computer games involves writing behaviors in a programming language and then iteratively refining them by detecting issues with them. The main bottlenecks are a) the effort required to author the behaviors and b) the revision cycle as, for most games, it is practically impossible to write a behavior for the computer game AI in a single attempt. The main problem is that the current development environments (IDE) are typically mere text editors that can only help the author by pointing out syntactical errors.
In this paper we present an intelligent IDE (iIDE) that has the following capabilities: it allows the author to program initial versions of the behaviors through demonstration, presents visualizations of behavior execution for revision, lets the author define failure conditions on the existing behavior set, and select appropriate fixes for the failure conditions to correct the behaviors. We describe the underlying techniques that support these capabilities inside our implemented iIDE and the future steps that need to be carried out to improve the iIDE. We also provide details on a preliminary user study showing how the new features inside the iIDE can help authors in behavior authoring and debugging in a real-time strategy game.
Read the paper:
An Intelligent IDE for Behavior Authoring in Real-Time Strategy Games
by Manish Mehta, Suhas Virmani, Yatin Kanetkar, Santi Ontañón, Ashwin Ram
4th Conference on Artificial Intelligence and Interactive Digital Entertainment (AIIDE-08), Stanford, CA, October 2008
www.cc.gatech.edu/faculty/ashwin/papers/er-08-08.pdf
9
Jul
Posted by cognitivecomputing in Learning, Talks. Tagged: goal-driven learning, meta-reasoning. Leave a comment
Goal-Driven Learning (GDL) views learning as a strategic process in which the learner attempts to identify and satisfy its learning needs in the context of its tasks and goals. This is modeled as a planful process where the learner analyzes its reasoning traces to identify learning goals, and composes a set of learning strategies (modeled as planning operators) into a plan to learn by satisfying those learning goals.
Traditional GDL frameworks were based on traditional planners. However, modern AI systems often deal with real-time scenarios where learning and performance happen in a reactive real-time fashion, or are composed of multiple agents that use different learning and reasoning paradigms. In this talk, I discuss new GDL frameworks that handle such problems, incorporating reactive and multi-agent planning techniques in order to manage learning in these kinds of AI systems.
About this talk:
New Directions in Goal-Driven Learning
by Ashwin Ram
Invited keynote at International Conference on Machine Learning (ICML-08) Workshop on Planning to Learn, Helsinki, Finland, July 2008
1
May
Posted by cognitivecomputing in Agents, Learning. Tagged: believable agents, meta-reasoning, problem solving. Leave a comment
We investigate how argumentation processes among a group of agents may affect the outcome of group judgments. In particular we focus on prediction markets (also called information markets). We investigate how the existence of social networks (that allow agents to argue with one another to improve their individual predictions) effect on group judgments.
Social networks allow agents to exchange information about the group judgment by arguing about the most likely choice based on their individual experience. We develop an argumentation-based deliberation process by which the agents acquire new and relevant information. Finally, we experimentally assess how different social network connectivity affect group judgment.
Read the paper:
Argumentation-based Information Exchange in Prediction Markets
by Santi Ontañón and Enric Plaza
in ArgMAS 2008, pp. 181 – 196
www.cc.gatech.edu/faculty/ashwin/papers/er-08-12.pdf
20
Feb
Posted by cognitivecomputing in Agents, Game AI, Learning. Tagged: believable agents, case-based reasoning, games, meta-reasoning, rts games, virtual worlds. Leave a comment
Game designers usually create AI behaviors by writing scripts that describe the reactions to all imaginable circumstances within the confines of the game world. The AI Programming Wisdom series provides a good overview of current scripting techniques used in the game industry. Scripting is expensive and it’s hard to plan. So, behaviors could be repetitive (resulting in breaking the atmosphere) or behaviors could fail to achieve their desired purpose. On one hand, creating AI with a rich behavior set requires a great deal of engineering effort on the part of game developers. On the other hand, the rich and dynamic nature of game worlds makes it hard to imagine and plan for all possible scenarios. When behaviors fail to achieve their desired purpose, the game AI is unable to identify such failure and will continue executing them. The techniques described in this article specifically deal with these issues.
Behavior (or script) creation for computer games typically involves two steps: a) generating a first version of behaviors using a programming language, b) debugging and adapting the behavior via experimentation. In this article we present techniques that aim at assisting the author from carrying out these two steps manually: behavior learning and behavior adaptation.
In the behavior learning process, the game developers can specify the AI behavior by demonstrating it to the system instead of having to code the behavior using a programming language. The system extracts behaviors from these expert demonstrations and stores them. Then, at performance time, the system retrieves appropriate behaviors observed from the expert and revises them in response to the current situation it is dealing with (i.e., to the current game state).
In the behavior adaptation process, the system monitors the performance of these learned behaviors at runtime. The system keeps track of the status of the executing behaviors, infer from their execution trace what might be wrong, and perform appropriate adaptations to the behaviors once the game is over. This approach to behavior transformation enables the game AI to reflect on the issues in the learnt behaviors from expert demonstration and revises them after post analysis of things that went wrong during the game. These set of techniques allow non-AI experts to define behaviors through demonstration that can then be adapted to different situations thereby reducing the development effort required to address all contingencies in a complex game.
Read the paper:
Adaptive Computer Games: Easing the Authorial Burden
by Manish Mehta, Santi Ontañón, Ashwin Ram
AI Game Programming Wisdom 4 (AIGPW4), Steve Rabin (editor), Charles River Media, 2008
www.cc.gatech.edu/faculty/ashwin/papers/er-08-03.pdf
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