Posts Tagged ‘case-based reasoning’

16 Aug

Case-Based Planning and Execution for Real-Time Strategy Games

Posted by cognitivecomputing in Game AI. Tagged: , , , , .

Artificial Intelligence techniques have been successfully applied to several computer games. However in some kinds of computer games, like real-time strategy (RTS) games, traditional artificial intelligence techniques fail to play at a human level because of the vast search spaces that they entail. In this paper we present a real-time case based planning and execution approach designed to deal with RTS games. We propose to extract behavioral knowledge from expert demonstrations in form of individual cases. This knowledge can be reused via a case based behavior generator that proposes behaviors to achieve the specific open goals in the current plan. Specifically, we applied our technique to the WARGUS domain with promising results.

Read the paper:

Case-Based Planning and Execution for Real-Time Strategy Games

by Santi Ontañón, Kinshuk Mishra, Neha Sugandh, Ashwin Ram

Seventh International Conference on Case-Based Reasoning (ICCBR-07), Belfast, Northern Ireland, August 2007
www.cc.gatech.edu/faculty/ashwin/papers/er-07-11.pdf

9 May

Towards Player Preference Modeling for Drama Management in Interactive Stories

Posted by cognitivecomputing in Game AI, Language. Tagged: , , , .

There is a growing interest in producing story based game experiences that do not follow fixed scripts pre-defined by the author, but change the experience based on actions performed by the player during his interaction. In order to achieve this objective, previous approaches have employed a drama management component that produces a narratively pleasing arc based on an author specified aesthetic value of a story, ignoring a player’s personal preference for that story path. Furthermore, previous approaches have used a simulated player model to assess their approach, ignoring real human players interacting with the story-based game.

This paper presents an approach that uses a case-based player preference modeling component that predicts an interestingness value for a particular plot point within the story. These interestingness values are based on real human players’ interactions with the story. We also present a drama manager that uses a search process (based on the expectimax algorithm) and combines the author specified aesthetic values with the player model.

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Towards Player Preference Modeling for Drama Management in Interactive Stories

by Manu Sharma, Santi Ontañón, Christina Strong, Manish Mehta, Ashwin Ram

20th International FLAIRS Conference on Artificial Intelligence (FLAIRS-07), Key West, FL, May 2007
www.cc.gatech.edu/faculty/ashwin/papers/er-07-03.pdf

8 May

Artificial Intelligence for Adaptive Computer Games

Posted by cognitivecomputing in Agents, Game AI, Learning, Talks. Tagged: , , , , .

Computer games are an increasingly popular application for Artificial Intelligence (AI) research, and conversely AI is an increasingly popular selling point for commercial games. Although games are typically associated with entertainment, there are many “serious” applications of gaming, including military, corporate, and advertising applications. There are also so-called “humane” gaming applications for medical training, educational games, and games that reflect social consciousness or advocate for a cause. Game AI is the effort of going beyond scripted interactions, however complex, into the arena of truly interactive systems that are responsive, adaptive, and intelligent. Such systems learn about the player(s) during game play, adapt their own behaviors beyond the pre-programmed set provided by the game author, and interactively develop and provide a richer experience to the player(s).

The long-term goal of our research is to develop artificial intelligence techniques that can have a significant impact in the game industry. We present a list of challenges and research opportunities in developing techniques that can be used by computer game developers. We discuss three Case Based Reasoning (CBR) approaches to achieve adaptability in games: automatic behavior adaptation for believable characters; drama management and user modeling for interactive stories; and strategic behavior planning for real-time strategy games.

Read the paper:

Artificial Intelligence for Adaptive Computer Games

by Ashwin Ram, Santi Ontañón, Manish Mehta

Invited talk at the 20th International FLAIRS Conference on Artificial Intelligence (FLAIRS-07), Special Track on Case-Based Reasoning, Key West, FL, May 2007
www.cc.gatech.edu/faculty/ashwin/papers/er-07-04.pdf

1 May

Learning and Joint Deliberation through Argumentation in Multi-Agent Systems

Posted by cognitivecomputing in Agents, Learning. Tagged: , .

We present an argumentation framework for learning agents (AMAL) designed for two purposes: (1) for joint deliberation, and (2) for learning from communication.  The AMAL framework is completely based on learning from examples: the argument preference relation, the argument generation policy, and the counterargument generation policy are case-based techniques.

For joint deliberation, learning agents share their experience by forming a committee to decide upon some joint decision. We experimentally show that the argumentation among committees of agents improves both the individual and joint performance. For learning from communication, an agent engages into arguing with other agents in order to contrast its individual hypotheses and receive counterexamples; the argumentation process improves their learning
scope and individual performance.

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Learning and Joint Deliberation through Argumentation in Multi-Agent Systems

by Santi Ontañón and Enric Plaza

in Autonomous Agents and Multi-Agent Systems (AAMAS 2007), pp. 971-978
www.cc.gatech.edu/faculty/ashwin/papers/er-07-19.pdf

11 Jan

Transfer Learning in Real-Time Strategy Games Using Hybrid CBR/RL

Posted by cognitivecomputing in Game AI, Learning. Tagged: , , , , .

The goal of transfer learning is to use the knowledge acquired in a set of source tasks to improve performance in a related but previously unseen target task. In this paper, we present a multi-layered architecture named CAse-Based Reinforcement Learner (CARL). It uses a novel combination of Case-Based Reasoning (CBR) and Reinforcement Learning (RL) to achieve transfer while playing against the Game AI across a variety of scenarios in MadRTS, a commercial Real-Time Strategy game. Our experiments demonstrate that CARL not only performs well on individual tasks but also exhibits significant performance gains when allowed to transfer knowledge from previous tasks.

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Transfer Learning in Real-Time Strategy Games Using Hybrid CBR/RL

by Manu Sharma, Michael Holmes, Juan Santamaria, Arya Irani, Charles Isbell, Ashwin Ram

International Joint Conference on Artificial Intelligence (IJCAI-07), Hyderabad, India, January 2007
www.cc.gatech.edu/faculty/ashwin/papers/er-07-01.pdf

1 Jan

Case-Based Learning from Proactive Communication

Posted by cognitivecomputing in Agents, Learning. Tagged: , .

We present a proactive communication approach that allows CBR agents to gauge the strengths and weaknesses of other CBR agents. The communication protocol allows CBR agents to learn from communicating with other CBR agents in such a way that each agent is able to retain certain cases provided by other agents that are able to improve their individual performance (without need to disclose all the contents of each case base). The selection and retention of cases is modeled as a case bartering process, where each individual CBR agent autonomously decides which cases offers for bartering and which offered barters accepts. Experimental evaluations show that the sum of all these individual decisions result in a clear improvement in individual CBR agent performance with only a moderate increase of individual case bases.

Read the paper:

Case-Based Learning from Proactive Communication

by Santi Ontañón and Enric Plaza

International Joint Conference on Artificial Intelligence (IJCAI 2007), pp. 999-1004
www.cc.gatech.edu/faculty/ashwin/papers/er-07-18.pdf

15 May

Case-Based Reasoning for Gas Turbine Diagnostics

Posted by cognitivecomputing in Learning. Tagged: , , .

General Electric used case-based reasoning for gas turbine diagnostics at their monitoring and diagnostics center in Atlanta, GA. This application had requirements that included accuracy, maintainability, modularity, parameterization, robustness, and integration of the system into an existing infrastructure. The CBR system has a modular “plug and play” architecture to facilitate experimentation and optimization. It was integrated into the production environment in 2004. The CBR system is currently in a trial deployment where diagnoses made by the system are created along with the previous process of using human-generated diagnosis.

Case-Based Reasoning for Gas Turbine Diagnostics

by Mark Devaney, Bill Cheetham

18th International FLAIRS Conference (FLAIRS-05), Clearwater, FL, May 2005
www.cc.gatech.edu/faculty/ashwin/papers/er-05-05.pdf

1 Apr

Preventing Failures by Mining Maintenance Logs with Case-Based Reasoning

Posted by cognitivecomputing in Language, Learning. Tagged: , .

The project integrates work in natural language processing, machine learning, and the semantic web, bringing together these diverse disciplines in a novel way to address a real problem. The objective is to extract and categorize machine components and subsystems and their associated failures using a novel approach that combines text analysis, unsupervised text clustering, and domain models. Through industrial partnerships, this project will demonstrate effectiveness of the proposed approach with actual industry data.

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Preventing Failures by Mining Maintenance Logs with Case-Based Reasoning

by Mark Devaney, Ashwin Ram, Hai Qui, Jay Lee

59th Meeting of the Society for Machinery Failure Prevention Technology (MFPT-59), Virginia Beach, VA, April 2005
www.cc.gatech.edu/faculty/ashwin/papers/er-05-04.pdf

1 Jan

Interactive Case-Based Reasoning for Precise Information Retrieval

Posted by cognitivecomputing in Language, Learning, Web / Web 2.0. Tagged: , , , .

The knowledge explosion has continued to outpace technological innovation in search engines and knowledge management systems. It is increasingly difficult to find relevant information, not just on the World Wide Web at large but even in domain- specific medium-sized knowledge bases—online helpdesks, maintenance records, technical repositories, travel databases, e-commerce sites, and many others. Despite advances in search and database technology, the average user still spends inordinate amounts of time looking for specific information needed for a given task.

This paper describes an adaptive system for the precise, rapid retrieval and synthesis of information from medium-sized knowledge bases in response to problem-solving queries from a diverse user population. We advocate a shift in perspective from “search” to “answers. Instead of returning dozens or hundreds of hits to a user, the system should attempt to find answers that may or may not match the query directly but are relevant to the user’s problem or task.

This problem has been largely overlooked as research has tended to concentrate on techniques for broad searches of large databases over the Internet (as exemplified by Google) and structured queries of well-defined databases (as exemplified by SQL). However, the problem discussed in this chapter is sufficiently different from these extremes to both present a novel set of challenges as well as provide a unique opportunity to apply techniques not traditionally found in the information retrieval literature. Specifically, we discuss an innovative combination of techniques‚ case-based reasoning coupled with text analytics‚ to solve the problem in a practical, real-world context.

We are interested in applications in which users must quickly retrieve answers to specific questions or problems from a complex information database with a minimum of effort and interaction. Examples include internal helpdesk support, web-based self-help for consumer products, decision-aiding systems for support personnel, and repositories for specialized documents such as patents, technical documents, or scientific literature. These applications are characterized by the fact that a diverse user population accesses highly focused knowledge bases in order to find precise answers to specific questions or problems. Despite the growing popularity of on-line service and support facilities for internal use by employees and for external use for customers, most such sites rely on traditional search engine technologies and are not very effective in reducing the time, expertise, and complexity required on the user’s part.

Read the paper:

Interactive Case-Based Reasoning for Precise Information Retrieval

by Ashwin Ram, Mark Devaney

In Case-Based Reasoning in Knowledge Discovery and Data Mining, David Aha and Sankar Pal (editors). 
www.cc.gatech.edu/faculty/ashwin/papers/er-05-02.pdf

1 Mar

Scaling Spreading Activation for Information Retrieval

Posted by cognitivecomputing in Language, Web / Web 2.0. Tagged: , , .

The Information Retrieval Intelligent Assistant (IRIA) project applies principles of memory retrieval from cognitive science to the problem of information retrieval from large heterogeneous databases. IRIA uses spreading activation over a semantic network for information retrieval, a technique which has proven effective in a variety of tasks. However, some of the very features which motivated the choice of spreading activation for information retrieval — such the use of fanout to automatically compute term weights, or the use of thresholds to automatically limit computation spent on irrelevant items — can introduce new problems as systems are scaled to larger sizes.

This paper discusses the use of semantic networks and spreading activation for information retrieval in the context of the IRIA approach, reviews some of the problems that arise as these technologies are scaled up to production systems, presents some preliminary results that illustrate these problems in practice, and discusses potential solutions.

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Scaling Spreading Activation for Information Retrieval

by Anthony Francis, Mark Devaney, Juan Santamaria, Ashwin Ram

International Conference on Artificial Intelligence (ICAI-01), Las Vegas, Nevada, March 2001
www.cc.gatech.edu/faculty/ashwin/papers/er-01-01.pdf
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