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Verbal Assistance in Tactile-Map Explorations: A Case for Visual Representations and Reasoning
Habel, Christopher (University of Hamburg) | Kerzel, Matthias (University of Hamburg) | Lohmann, Kris (University of Hamburg)
Tactile maps offer access to spatial-analog information for visually impaired people. In contrast to visual maps, a tactile map has a lower resolution and can only be inspected in a sequential way, complicating the extraction of spatial relations among distant map entities. Verbal assistance can help to overcome these difficulties by substituting textual labels with verbal descriptions and offering propositional knowledge about spatial relations. Like visual maps, tactile maps are based on visual, spatial-geometric representations that need to be reasoned about in order to generate verbal assistance. We present an approach towards a verbally assisting virtual-environment tactile map (VAVETaM) realized on a computer system utilizing a haptic force-feedback device. In particular, we discuss the tasks of understanding the user's map exploration procedures (MEPs), of exploiting the spatial-analog map to anticipate the user's informational needs, of reasoning about optimal assistance by taking assumed prior knowledge of the user into account, and of generating appropriate verbal instructions and descriptions to augment the map.
Decentralised Metacognition in Context-Aware Autonomic Systems: Some Key Challenges
Kennedy, Catriona (Massachusetts Institute of Technology)
A distributed non-hierarchical metacognitive architec- ture is one in which all meta-level reasoning compo- nents are subject to meta-level monitoring and manage- ment by other components. Such metacognitive distri- bution can support the robustness of distributed IT sys- tems in which humans and arti๏ฌcial agents are partic- ipants. However, robust metacognition also needs to be context-aware and use diversity in its reasoning and analysis methods. Both these requirements mean that an agent evaluates its reasoning within a โbigger pictureโ and that it can monitor this global picture from multi- ple perspectives. In particular, social context-awareness involves understanding the goals and concerns of users and organisations. In this paper, we ๏ฌrst present a conceptual architecture for distributed metacognition with context-awareness and diversity. We then consider the challenges of apply- ing this architecture to autonomic management systems in scenarios where agents must collectively diagnose and respond to errors and intrusions. Such autonomic systems need rich semantic knowledge and diverse data sources in order to provide the necessary context for their metacognitive evaluations and decisions.
Hierarchical Planning for Mobile Manipulation
Wolfe, Jason (University of California, Berkeley) | Marthi, Bhaskara (Willow Garage, Inc) | Russell, Stuart (University of California, Berkeley)
Humans somehow manage to choose quite intelligently planner should fill in to produce a concrete plan that accomplishes the 20 trillion primitive motor commands that constitute a the goal as quickly as possible. It has long been thought that hierarchical structure in Planning at multiple levels of abstraction has long been a behavior is essential in managing this complexity. For instance, Shakey the exists at many levels, ranging from small (hundred-step?) robot used STRIPS for high-level task planning, then called motor programs for typing characters and saying phonemes out to separate low-level planning/control algorithms to execute up to large (billion-step?) actions such as writing an ICAPS each of the planned actions (Fikes and Nilsson 1971). This hard separation of levels, where a high-level plan is We believe that leveraging hierarchical structure will be chosen before considering low-level details, greatly simplifies equally important in achieving robust, efficient robotic behaviors. However, the resulting plans While your household robot probably won't get may be inefficient or even infeasible due to missed lowerlevel tenure anytime soon, even simple domestic tasks still have synergies and conflicts.
Teamwork and Coordination under Model Uncertainty in DEC-POMDPs
Kwak, Jun-young (University of Southern California) | Yang, Rong (University of Southern California) | Yin, Zhengyu (University of Southern California) | Taylor, Matthew E. (University of Southern California) | Tambe, Milind (University of Southern California)
Distributed Partially Observable Markov Decision Processes (DEC-POMDPs) are a popular planning framework for multiagent teamwork to compute (near-)optimal plans. However, these methods assume a complete and correct world model, which is often violated in real-world domains. We provide a new algorithm for DEC-POMDPs that is more robust to model uncertainty, with a focus on domains with sparse agent interactions. Our STC algorithm relies on the following key ideas: (1) reduce planning-time computation by shifting some of the burden to execution-time reasoning, (2) exploit sparse interactions between agents, and (3) maintain an approximate model of agentsโ beliefs. We empirically show that STC is often substantially faster to existing DEC-POMDP methods without sacrificing reward performance.
Evolutionary Tile Coding: An Automated State Abstraction Algorithm for Reinforcement Learning
Lin, Stephen (Air Force Research Laboratory โ Information Directorate) | Wright, Robert (Air Force Research Laboratory โ Information Directorate)
Reinforcement learning (RL) algorithms have the ability to learn optimal policies for control problems by exploring a domain's state space. Unfortunately, for most problems the size of the state space is too great for RL technologies to fully explore in order to find good policies. State abstraction is one way of reducing the size and complexity of a domain's state space in order to enable RL. In this paper we introduce a new approach for automatically deriving state abstractions called Evolutionary Tile Coding that uses a genetic algorithm for deriving effective tile codings. We provide an empirical analysis of the new algorithm comparing it to another adaptive tile coding method as well as fixed tile coding. Our results show that our approach is able to automatically derive effective state abstractions for two RL benchmark problems. Additionally, we present an intriguing result that shows the classical mountain car problem's state space can be reduced to just two states and still preserve the discovery of an optimal policy.
Preface
Nastase, Vivi (HITS gGmbH) | Navigli, Roberto (Sapienza Universita di Roma) | Wu, Fei (University of Washington)
Until recently, the AI and in particular the NLP community GA, immediately preceding the Twenty-Fourth AAAI Conference have relied on resources built manually by experts in on Artificial Intelligence -- AAAI 2010. It is a successor specific areas (in particular linguists, philosophers, cognitive to the workshops organized at AAAI 2008 entitled linguists). User contributed knowledge has opened up "Wikipedia and Artificial Intelligence: An Evolving Synergy" a new perspective, in that it captures the kind of knowledge (WikiAI 08) and at IJCAI 2009 entitled "User Contributed and organization that arises naturally out of the consensus Knowledge and Artificial Intelligence: An Evolving of the masses, and as such represents better our collective Synergy" (WikiAI 09). The outcome is a multifaceted and extremely This volume contains papers accepted for presentation at rich source of information, revealed through embedded annotations the workshop. We issued calls for regular papers, short latebreaking and structural information.
Leveraging Ontologies for Lifted Probabilistic Inference and Learning
Kiddon, Chloe Marielle (University of Washington) | Domingos, Pedro (University of Washington)
Exploiting ontologies for efficient inference is one of the most widely studied topics in knowledge representation and reasoning. The use of ontologies for probabilistic inference, however, is much less developed. A number of algorithms for lifted inference in first-order probabilistic languages have been proposed, but their scalability is limited by the combinatorial explosion in the sets of objects that need to be considered. We propose a coarse-to-fine inference approach that leverages a class hierarchy to combat this problem. Starting at the highest level, our approach performs inference at successively finer grains, pruning low-probability atoms before refining. We provide bounds on the error incurred by this approach relative to full ground inference as a function of the pruning threshold. We also show how to learn parameters in a coarse-to-fine manner to maximize the opportunities for pruning during inference. Experiments on link prediction and biomolecular event prediction tasks show our method can greatly improve the scalability of lifted probabilistic inference.
Handling Looping and Optional Actions in YAPPR
Geib, Christopher (University of Edinburgh) | Goldman, Robert (SIFT LLC)
Previous work on the YAPPR plan recognition system provided algorithms for translating conventional HTN plan libraries into lexicalized grammars and treated the problem of plan recognition as one of parsing. To produce these grammars required a fixed bound for any loops within the grammar and a presented a problem for optional actions within HTN plans. In this work we show that well known transformations from formal language theory can be used to rewrite the plan grammars to remove these limitations on the plan libraries.
Search Performance of Multi-Agent Plan Recognition in a General Model
Banerjee, Bikramjit (University of Southern Mississippi) | Kraemer, Landon (University of Southern Mississippi)
Multi-Agent Plan Recognition (MAPR) seeks to identify the dynamic team structures and team behaviors from the observations of the activity-sequences of a set of intelligent agents, based on a library of known team-activities (plan library). It has important applications in analyzing data from automated monitoring, surveillance, and intelligence analysis in general. Recently, we have introduced a model for MAPR with a flat library structure, to study the complexity of basic MAPR, and also possibly its extensions in the future. Interestingly, this model makes fewer assumptions than existing models, and hence is more general. Therefore, as no existing algorithm would apply to this model, we have developed an hypothesis generation algorithm for this model, and adapted Knuth's Algorithm X for branch and bound search in the resulting hypothesis space. In this paper, we establish the time complexity of hypothesis generation in this model, propose and evaluate 3 different bounding criteria, and also empirically study the dependence of runtimes (hypothesis generation, and search times separately) on the model parameters.
Visualization for Structured Constraint Satisfaction Problems
Li, Xingjian (The Graduate Center of The City Unversity of New York) | Epstein, Susan L. (The Graduate Center and Hunter College of The City University of New York)
Constraint satisfaction problems are mathematical models of real-world problems. In contrast to randomly generated artificial problems, real-world problems usually have non-random structure. Knowledge about that structure, when identified in advance, can make search to find solutions more effective. This paper introduces DrawCSP, a visualization program that can show both the original and the discovered structure of constraint satisfaction problems. DrawCSP provides insight into both search algorithm design and into the challenges real-world problems present.