Agents
A Framework for Sequential Planning in Multi-Agent Settings
Gmytrasiewicz, P. J., Doshi, P.
This paper extends the framework of partially observable Markov decision processes (POMDPs) to multi-agent settings by incorporating the notion of agent models into the state space. Agents maintain beliefs over physical states of the environment and over models of other agents, and they use Bayesian updates to maintain their beliefs over time. The solutions map belief states to actions. Models of other agents may include their belief states and are related to agent types considered in games of incomplete information. We express the agents' autonomy by postulating that their models are not directly manipulable or observable by other agents. We show that important properties of POMDPs, such as convergence of value iteration, the rate of convergence, and piece-wise linearity and convexity of the value functions carry over to our framework. Our approach complements a more traditional approach to interactive settings which uses Nash equilibria as a solution paradigm. We seek to avoid some of the drawbacks of equilibria which may be non-unique and do not capture off-equilibrium behaviors. We do so at the cost of having to represent, process and continuously revise models of other agents. Since the agent's beliefs may be arbitrarily nested, the optimal solutions to decision making problems are only asymptotically computable. However, approximate belief updates and approximately optimal plans are computable. We illustrate our framework using a simple application domain, and we show examples of belief updates and value functions.
Calendar of Events
(EDOC 2005). Moscow State University, Russia, King's Email: patrick.hung@uoit.ca In cooperation with the American Association for Artificial Intelligence General Chairs The 19th International FLAIRS Conference (FLAIRS 2006) will be held May 11-13 Philip Chan, Debasis Mitra 2006, in Melbourne Beach, Florida, USA. Coast" (centered around NASA's Kennedy Space Center), and has easy access to Florida Institute of Technology Orlando and the Disney World attractions. Submission of papers for presentation at the conference is now invited.
Reports on the 2005 AAAI Spring Symposium Series
Anderson, Michael L., Barkowsky, Thomas, Berry, Pauline, Blank, Douglas, Chklovski, Timothy, Domingos, Pedro, Druzdzel, Marek J., Freksa, Christian, Gersh, John, Hegarty, Mary, Leong, Tze-Yun, Lieberman, Henry, Lowe, Ric, Luperfoy, Susann, Mihalcea, Rada, Meeden, Lisa, Miller, David P., Oates, Tim, Popp, Robert, Shapiro, Daniel, Schurr, Nathan, Singh, Push, Yen, John
Techniques in this symposium series were he calls the "twenty-first century for analyzing terrorist networks (1) AI Technologies for Homeland Security; strategic threat triad," which consists were reported by Alphatech (2) Challenges to Decision of failed states, global terrorism, and and the University of Arizona. Popp noted that and retrieving information for Robots: Verbal Interaction with convergence of these three elements counter intelligence was demonstrated Embodied Agents and Situated Devices; is highly destabilizing and a key by Jim Hendler of the University (5) Knowledge Collection from strategic concern to the national security of Maryland. They also aimed to chart out future from Stanford University, Lawrence For example, systems that are research agenda by identifying specific Livermore Laboratories, SRI International, based on probabilistic or decisiontheoretic interesting issues in various and Syracuse University. Homeland security applications for unable to cope with change by themselves, The recurrent themes from data mining and mobile robots were as neither probability theory the presentations included the following: reported by Alphatech and the University nor decision theory says much about of South Florida, respectively. How do The highlights of the symposium let alone how they should be modified.
AAAI-05: Twentieth National AI Conference Is a Panoply of Content
After rigorous evaluation, 150 papers were accepted for oral presentation, and 79 for poster presentation. The analogical and case based reasoning category features 6 papers; auctions and market-based systems features 5 papers, and automated reasoning ... out over the Ocean, the winter State University), Amy Greenwald features 12 papers. Twenty papers sky is brilliant panoply of (Brown University), Marti Hearst will be published in constraint stars and comets, beckoning to (University of California, Berkeley), satisfaction and satisfiability; game adventurers... who seek to divine Sridhar Mahadevan (University of theory and economic models features its mysteries. Machine his year marks the twenty-fifth for Artificial Intelligence pioneer and visionary Jay M. ("Marty") learning, the category with the and the twentieth National Tenenbaum4 who will speak on largest number of papers, has 35, Conference on AI (AAAI-05).1 The "The Future of AI and the Web"; while machine perception has 6.
An Expressive Language and Efficient Execution System for Software Agents
Software agents can be used to automate many of the tedious, time-consuming information processing tasks that humans currently have to complete manually. However, to do so, agent plans must be capable of representing the myriad of actions and control flows required to perform those tasks. In addition, since these tasks can require integrating multiple sources of remote information ? typically, a slow, I/O-bound process ? it is desirable to make execution as efficient as possible. To address both of these needs, we present a flexible software agent plan language and a highly parallel execution system that enable the efficient execution of expressive agent plans. The plan language allows complex tasks to be more easily expressed by providing a variety of operators for flexibly processing the data as well as supporting subplans (for modularity) and recursion (for indeterminate looping). The executor is based on a streaming dataflow model of execution to maximize the amount of operator and data parallelism possible at runtime. We have implemented both the language and executor in a system called THESEUS. Our results from testing THESEUS show that streaming dataflow execution can yield significant speedups over both traditional serial (von Neumann) as well as non-streaming dataflow-style execution that existing software and robot agent execution systems currently support. In addition, we show how plans written in the language we present can represent certain types of subtasks that cannot be accomplished using the languages supported by network query engines. Finally, we demonstrate that the increased expressivity of our plan language does not hamper performance; specifically, we show how data can be integrated from multiple remote sources just as efficiently using our architecture as is possible with a state-of-the-art streaming-dataflow network query engine.
Hybrid BDI-POMDP Framework for Multiagent Teaming
Many current large-scale multiagent team implementations can be characterized as following the ``belief-desire-intention'' (BDI) paradigm, with explicit representation of team plans. Despite their promise, current BDI team approaches lack tools for quantitative performance analysis under uncertainty. Distributed partially observable Markov decision problems (POMDPs) are well suited for such analysis, but the complexity of finding optimal policies in such models is highly intractable. The key contribution of this article is a hybrid BDI-POMDP approach, where BDI team plans are exploited to improve POMDP tractability and POMDP analysis improves BDI team plan performance. Concretely, we focus on role allocation, a fundamental problem in BDI teams: which agents to allocate to the different roles in the team. The article provides three key contributions. First, we describe a role allocation technique that takes into account future uncertainties in the domain; prior work in multiagent role allocation has failed to address such uncertainties. To that end, we introduce RMTDP (Role-based Markov Team Decision Problem), a new distributed POMDP model for analysis of role allocations. Our technique gains in tractability by significantly curtailing RMTDP policy search; in particular, BDI team plans provide incomplete RMTDP policies, and the RMTDP policy search fills the gaps in such incomplete policies by searching for the best role allocation. Our second key contribution is a novel decomposition technique to further improve RMTDP policy search efficiency. Even though limited to searching role allocations, there are still combinatorially many role allocations, and evaluating each in RMTDP to identify the best is extremely difficult. Our decomposition technique exploits the structure in the BDI team plans to significantly prune the search space of role allocations. Our third key contribution is a significantly faster policy evaluation algorithm suited for our BDI-POMDP hybrid approach. Finally, we also present experimental results from two domains: mission rehearsal simulation and RoboCupRescue disaster rescue simulation.
The Workshop Program at the Nineteenth National Conference on Artificial Intelligence
Muslea, Ion, Dignum, Virginia, Corkill, Daniel, Jonker, Catholijn, Dignum, Frank, Coradeschi, Silvia, Saffiotti, Alessandro, Fu, Dan, Orkin, Jeff, Cheetham, William E., Goebel, Kai, Bonissone, Piero, Soh, Leen-Kiat, Jones, Randolph M., Wray, Robert E., Scheutz, Matthias, Farias, Daniela Pucci de, Mannor, Shie, Theocharou, Georgios, Precup, Doina, Mobasher, Bamshad, Anand, Sarabjot Singh, Berendt, Bettina, Hotho, Andreas, Guesgen, Hans, Rosenstein, Michael T., Ghavamzadeh, Mohammad
AAAI presented the AAAI-04 workshop program on July 25-26, 2004 in San Jose, California. This program included twelve workshops covering a wide range of topics in artificial intelligence. The titles of the workshops were as follows: (1) Adaptive Text Extraction and Mining; (2) Agent Organizations: Theory and Practice; (3) Anchoring Symbols to Sensor Data; (4) Challenges in Game AI; (5) Fielding Applications of Artificial Intelligence; (6) Forming and Maintaining Coalitions in Adaptive Multiagent Systems; (7) Intelligent Agent Architectures: Combining the Strengths of Software Engineering and Cognitive Systems; (8) Learning and Planning in Markov Processes -- Advances and Challenges; (9) Semantic Web Personalization; (10) Sensor Networks; (11) Spatial and Temporal Reasoning; and (12) Supervisory Control of Learning and Adaptive Systems.
AAAI News
Posters, and the AAAI/ SIGART consist of two phases: a qualification Doctoral Consortium. Please visit the round and a runoff competition. A AAAI is pleased to announce the AAAI-05 web site periodically for upto-date $10,000 prize will be awarded to the launch of the First Annual Artificial information. We hope you will winning entrant. The competition is Intelligence for Interactive Digital join us in Pittsburgh!
The Workshop Program at the Nineteenth National Conference on Artificial Intelligence
Muslea, Ion, Dignum, Virginia, Corkill, Daniel, Jonker, Catholijn, Dignum, Frank, Coradeschi, Silvia, Saffiotti, Alessandro, Fu, Dan, Orkin, Jeff, Cheetham, William E., Goebel, Kai, Bonissone, Piero, Soh, Leen-Kiat, Jones, Randolph M., Wray, Robert E., Scheutz, Matthias, Farias, Daniela Pucci de, Mannor, Shie, Theocharou, Georgios, Precup, Doina, Mobasher, Bamshad, Anand, Sarabjot Singh, Berendt, Bettina, Hotho, Andreas, Guesgen, Hans, Rosenstein, Michael T., Ghavamzadeh, Mohammad
AAAI presented the AAAI-04 workshop program on July 25-26, 2004 in San Jose, California. This program included twelve workshops covering a wide range of topics in artificial intelligence. The titles of the workshops were as follows: (1) Adaptive Text Extraction and Mining; (2) Agent Organizations: Theory and Practice; (3) Anchoring Symbols to Sensor Data; (4) Challenges in Game AI; (5) Fielding Applications of Artificial Intelligence; (6) Forming and Maintaining Coalitions in Adaptive Multiagent Systems; (7) Intelligent Agent Architectures: Combining the Strengths of Software Engineering and Cognitive Systems; (8) Learning and Planning in Markov Processes -- Advances and Challenges; (9) Semantic Web Personalization; (10) Sensor Networks; (11) Spatial and Temporal Reasoning; and (12) Supervisory Control of Learning and Adaptive Systems.
The Seventeenth Canadian Conference on Artificial Intelligence (AI'2004)
AI'2004 was held at the University of AI'2004 had a large program committee were affiliated with AI'2004: The Third Canada (NRC) (who also hosted the hosted one of the longest-running and the First Causality and preconference workshops) cosponsored conference series in the AI field. The Causal Discovery workshop, organized the AI'2004 Graduate Symposium. CSCSI conference started in 1976 as a by Kamran Karimi (University of Regina). The Eighteenth Canadian Conference the conference became an annual forum, In addition, the AI'2004 graduate on Artificial Intelligence thus making AI'2004 the seventeenth symposium attracted many graduate (AI'2005) will be held in Victoria, conference in this series. These events turned the city British Columbia, from May 9 to 11, the years, the conference has attracted of London into a Mecca for AI and 2005.