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A Formal Systems Approach to Machine Capture, Representation and Use of Activity Context

AAAI Conferences

Britain's trains are not noted for their AAAI Activity Context Representation Workshop. The punctuality and they are deemed on-time within a window first paper, 'Defining and Representing Activity Context of ten or so minutes, so just using the train timetable to for Systems Analysis', summarizes the author's formal predict bad spots is not feasible. Over a number of journeys, Simplified Set Theory (SST) approach and the use of his the user attempts to find journey landmarks that precede PentaVenn diagram. This second paper uses these in a the bad spots by a few minutes ("a few" being less modest, partially worked example to explore the contexts than the predicted time for file transfer). Some landmarks of an activity and how a formal approach can aid systems might be easy to identify, e.g.


Scalable Visualization Resizing Framework

AAAI Conferences

Effective visualization resizing is important for many visualization tasks, where users may have display devices with different sizes and aspect ratios. Our recently designed framework can adapt a visualization to different displays by transforming the resizing problem into a non-linear optimization problem. However, it is not scalable to a large amount of dense information. Undesired cluttered results would be produced if dense information is presented in the target display. We present an extension to our resizing framework with a seamless integration of a sampling-based data abstraction mechanism, such that it is scalable with not only different display sizes, but also different amounts of information.


Multi-Fisheye for Interactive Visualization of Large Graphs

AAAI Conferences

By selectively zooming in and zooming out visualizations, the fisheye technique allows users to study details while maintaining context. In this paper, weintroduce a multi-fisheye technique, which amounts to introducing several fisheyes in a visualization at the same time. Our multi-fisheye technique isbased on partitioning the visualization's display area and applying a fisheye algorithm inside each partition. While we demonstrate the potential ofapplying our multi-fisheye technique using a social network, it clearly can be applied in other areas and types of networks, including in probabilisticgraphical models such as Bayesian networks.


Agent Based Intelligent Decluttering Enhancements

AAAI Conferences

Model-driven visualization (MDV) is a novel framework that supports more effective, intelligent user interfaces to improve decision making in complex environments by coupling cognitive and perceptual theories of information processing with advanced artificial intelligence methods. It embeds empirical and theory driven approaches for identifying and prioritizing data based on the information requirements and needs of the human decision maker within intelligent agents. The agents automatically deliver and present information based on its likely value using visualizations that best convey that information to the user(s) of the system. Agents also reason about the context and constraints of the user, environment, and display to enable a higher degree of personalization within an interactive user interface (e.g., by drawing a userโ€™s attention to interesting aspects of the data such as trends, anomalies, and patterns). We apply cognitive systems engineering processes to help identify the information available to individuals and/or teams, where it resides, where it is needed, and ultimately how to create the mappings required in connecting critical information to those who need it with innovative visualizations that most effectively support the end user. This paper describes the application of MDV to intelligently deliver timely, mission-critical information by adapting a Common Tactical Picture (CTP) display used for maritime situation awareness, threat assessment, and decision support.


Human Activity Detection from RGBD Images

AAAI Conferences

Being able to detect and recognize human activities is important for making personal assistant robots useful in performing assistive tasks. The challenge is to develop a system that is low-cost, reliable in unstructured home settings, and also straightforward to use. In this paper, we use a RGBD sensor (Microsoft Kinect) as the input sensor, and present learning algorithms to infer the activities. Our algorithm is based on a hierarchical maximum entropy Markov model (MEMM). It considers a person's activity as composed of a set of sub-activities, and infers the two-layered graph structure using a dynamic programming approach. We test our algorithm on detecting and recognizing twelve different activities performed by four people in different environments, such as a kitchen, a living room, an office, etc., and achieve an average performance of 84.3% when the person was seen before in the training set (and 64.2% when the person was not seen before).


Detecting and Identifying Coalitions

AAAI Conferences

In many multiagent scenarios, groups of participants (known as coalitions) may attempt to cooperate, seeking to increase the benefits realized by the members. Depending on the scenario, such cooperation may be benign, or may be unwelcome or even forbidden (often called collusion). Coalitions can present a problem for many multiagent systems, potentially undermining the intended operation of systems. In this paper, we present a technique for detecting the presence of coalitions (malicious or otherwise), and identifying their members. Our technique employs clustering in benefit space, a high-dimensional feature space reflecting the benefit flowing between agents, in order to identify groups of agents who are similar in terms of the agents they are favoring. A statistical approach is then used to characterize candidate clusters, identifying as coalitions those groups that favor their own members to a much greater degree than the general population. We believe that our approach is applicable to a wide range of domains. Here, we demonstrate its effectiveness within a simulated marketplace making use of a trust and reputation system to cope with dishonest sellers. Many trust and reputation proposals readily acknowledge their ineffectiveness in the face of collusion, providing one example of the importance of the problem. While certain aspects of coalitions have received significant attention (e.g., formation, stability, etc.), relatively little research has focused on the problem of coalition identification. We believe our research represents an important step towards addressing the challenges posed by coalitions.


Role-Based Ad Hoc Teamwork

AAAI Conferences

An ad hoc team setting is one in which teammates must work together to obtain a common goal, but without any prior agreement regarding how to work together. In this paper we present a role-based approach for ad hoc teamwork, in which each teammate is inferred to be following a specialized role that accomplishes a specific task or exhibits a particular behavior. In such cases, the role an ad hoc agent should select depends both on its own capabilities and on the roles currently selected by the other team members. We formally define methods for evaluating the influence of the ad hoc agent's role selection on the team's utility, leading to an efficient calculation of the role that yields maximal team utility. In simple teamwork settings, we demonstrate that the optimal role assignment can be easily determined. However, in complex environments, where it is not trivial to determine the optimal role assignment, we examine empirically the best suited method for role assignment. Finally, we show that the methods we describe have a predictive nature. As such, once an appropriate assignment method is determined for a domain, it can be used successfully in new tasks that the team has not encountered before and for which only limited prior experience is available.


Fixing a Hole in Lexicalized Plan Recognition

AAAI Conferences

Previous work has suggested the use of lexicalized grammars for probabilistic plan recognition. Such grammars allow the domain builder to delay commitment to hypothesizing high level goals in order to reduce computational costs. However this delay has limitations. In the case of only partial observation traces, delaying commitment can prevent such algorithms from forming correct conclusions about some goals. This paper presents a heuristic metric to address this limitation. It advocates computing the maximum change in conditional probability across all the computed explanations given the observations explicitly considering a goal of interest.


Discovering Patterns of Autistic Planning

AAAI Conferences

We analyze the patterns of autistic reasoning while performing planning tasks. The formalism of non-monotonic logic of defaults is used to simulate the autistic decision-making while adjusting an action to a context. Our current main finding is that while people with autism may be able to process single default rules, they have a characteristic difficulty in cases where multiple default rules conflict. Even though default reasoning was intended to simulate the reasoning of typical human subjects, it turns out that following the operational semantics of default reasoning in a literal way leads to the peculiarities of autistic behavior observed in the literature.


Lifelong Credit Assignment with the Success-Story Algorithm

AAAI Conferences

Consider an embedded agent with a self-modifying, Turing-equivalent policy that can change only through active self-modifications. How can we make sure that it learns to continually accelerate reward intake? Throughout its life the agent remains ready to undo any self-modification generated during any earlier point of its life, provided the reward per time since then has not increased, thus enforcing a lifelong success-story of self-modifications, each followed by long-term reward acceleration up to the present time. The stack-based method for enforcing this is called the success-story algorithm. It fully takes into account that early self-modifications set the stage for later ones (learning a learning algorithm), and automatically learns to extend self-evaluations until the collected reward statistics are reliable ... a very simple but general method waiting to be re-discovered! Time permitting, I will also briefly discuss more recent mathematically optimal universal maximizers of lifelong reward, in particular, the fully self-referential Goedel machine.