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Continual HTN Robot Task Planning in Open-Ended Domains: A Case Study

AAAI Conferences

The fact that many AI planning approaches are still based on too simplifying assumptions makes it often hard to apply these approaches to real-world robotics. In particular, it is in many cases difficult to generate a complete plan in advance, because not all information is available at the beginning of the planning process. We briefly present the continual planning system ACogPlan and a preliminary test case that demonstrates how the planning system can enable mobile robots to continually plan and execute activities in an open-ended domain.


Deep Belief Nets as Function Approximators for Reinforcement Learning

AAAI Conferences

We describe a continuous state/action reinforcement learning method which uses deep belief networks (DBNs) in conjunction with a value function-based reinforcement learning algorithm to learn effective control policies. Our approach is to first learn a model of the state-action space from data in an unsupervised pre-training phase, and then use neural-fitted Q-iteration (NFQ) to learn an accurate value function approximator (analogous to a "fine-tuning" phase when training DBNs for classification). Our experiments suggest that this approach has the potential to significantly increase the efficiency of the learning process in NFQ, provided care is taken to ensure the initial data covers interesting areas of the state-action space, and may be particularly useful in transfer learning settings.


Visualizing and Understanding Large-Scale Bayesian Networks

AAAI Conferences

Bayesian networks are a theoretically well-founded approach to represent large multi-variate probability distributions, and have proven useful in a broad range of applications. While several software tools for visualizing and editing Bayesian networks exist, they have important weaknesses when it comes to enabling users to clearly understand and compare conditional probability tables in the context of network topology, especially in large-scale networks. This paper describes a system for improving the ability for computers to work with people to develop intelligent systems through the construction of high-performing Bayesian networks. We describe NetEx, a tool developed as a Cytoscape plug-in, which allows a user to visually inspect and compare details concerning multiple nodes in a Bayesian network while maintaining awareness of their network context. It uses a "thought bubble line" to connect nodes in a graph representation and their internal information at the side of the graph. The tool seeks to improve the ability of experts to analyze and debug large Bayesian network models, and to help people to understand how alternative algorithms and Bayesian networks operate, providing insights into how to improve them.


User-Adaptive Visualizations: Can Gaze Data Tell Us When a User Needs Them?

AAAI Conferences

The primary goal of our research is to design adaptive information visualization systems that adapt to the specific needs of each individual viewer. Our first step is to explore data sources that could help detect these needs in real-time, including cognitive measures that impact perceptual abilities, interface interactions, eye-tracking, and physiological sensors. In this paper, we focus on current efforts to understand which cognitive measures can be relevant, as well as if/how a viewerโ€™s gaze pattern can predict performance on associated visualization task.


Whatโ€™s the Right Price? Pricing Tasks for Finishing on Time

AAAI Conferences

Many practitioners currently use rules of thumb to price tasks on online labor markets. Incorrect pricing leads to task starvation or inefficient use of capital. Formal pricing policies can address these challenges. In this paper we argue that a pricing policy can be based on the trade-off between price and desired completion time.We show how this duality can lead to a better pricing policy for tasks in online labor markets. This paper makes three contributions. First, we devise an algorithm for job pricing using a survival analysis model. We then show that worker arrivals can be modeled as a non-homogeneous Poisson Process (NHPP). Finally using NHPP for worker arrivals and discrete choice models we present an abstract mathematical model that captures the dynamics of the market when full market information is presented to the task requester. This model can be used to predict completion times and pricing policies for both public and private crowds.


Labor Allocation in Paid Crowdsourcing: Experimental Evidence on Positioning, Nudges and Prices

AAAI Conferences

This paper reports the results of a natural field experiment where workers from a paid crowdsourcing environment self-select into tasks and are presumed to have limited attention. In our experiment, workers labeled any of six pictures from a 2 x 3 grid of thumbnail images. In the absence of any incentives, workers exhibit a strong default bias and tend to select images from the top-left (``focal'') position; the bottom-right (``non-focal'') position, was the least preferred. We attempted to overcome this bias and increase the rate at which workers selected the least preferred task, by using a combination of monetary and non-monetary incentives. We also varied the saliency of these incentives by placing them in either the focal or non-focal position. Although both incentive types caused workers to re-allocate their labor, monetary incentives were more effective. Most interestingly, both incentive types worked better when they were placed in the focal position and made more salient. In fact, salient non-monetary incentives worked about as well as non-salient monetary ones. Our evidence suggests that user interface and cognitive biases play an important role in online labor markets and that salience can be used by employers as a kind of ``incentive multiplier.''


Self-Reconfiguration in Modular Robots Using Coalition Games with Uncertainty

AAAI Conferences

We consider the problem of dynamic self-reconfiguration in a modular self-reconfigurable robot (MSR). Previous MSR self-reconfiguration approaches search for new configurations only within the modules of the MSR that needs reconfiguration. In contrast, we describe a technique where an MSR that needs to reconfigure communicates with other MSRs in its vicinity to determine if modules can be shared from other MSRs, and then determines the best possible configuration among the combined set of modules. We model the MSR self-reconfiguration problem as a coalition structure generation problem within a coalition game theoretic framework. We formulate the coalition structure generation problem as a planning problem in the presence of uncertainty and propose an MDP-based algorithm to solve it. We have implemented our algorithm within an MSR called ModRED that is simulated on the Webots simulation platform. Our results show that using our self-reconfiguration algorithm, when an MSR needs to reconfigure, a new configuration that is within 5-7% of the globally optimal configuration can be determined. We have also shown that our algorithm performs comparably with another existing algorithm for determining optimal coalition structure.


Mixed-Initiative Interfaces for Slide-Ware Authoring and Presentation

AAAI Conferences

We present current work on the NextSlidePlease slide- ware presentation tool and discuss how mixed-initiative principles may support the complex tasks of combin- ing multiple linear presentations into a network of re- lated content. We discuss future directions in two areas: supporting the layout of complex sets of interconnected slides, and refining the time requirements and content importance in these networks.


Turkomatic: Automatic, Recursive Task and Workflow Design for Mechanical Turk

AAAI Conferences

On today's human computation systems, designing tasks and workflows is a difficult and labor-intensive process. Can workers from the crowd be used to help plan workflows? We explore this question with Turkomatic, a new interface to microwork platforms that uses crowd workers to help plan workflows for complex tasks. Turkomatic uses a general-purpose divide-andconquer algorithm to solve arbitrary natural-language requests posed by end users. The interface includes a novel real-time visual workflow editor that enables requesters to observe and edit workflows while the tasks are being completed. Crowd verification of work and the division of labor among members of the crowd can be handled automatically by Turkomatic, which substantially simplifies the process of using human computation systems. These features enable a novel means of interaction with crowds of online workers to support successful execution of complex work. Figure 1: Turkomatic harnesses crowds to plan and execute complex work requested in natural language.


A Social Collaboration Argumentation System for Generating Multi-Faceted Answers in Question and Answer Communities

AAAI Conferences

In this paper, we propose an innovative approach for the development of social collaboration argumentation systems. These systems enable a community to collaboratively create answers to questions where many possible answers, or nuanced perspectives on a single answer, can be posited. We examine the emergence of critical reasoning via crowdsourced structured discussions, which are built upon a graph-theoretic framework populated by atomic argumentation components. Finally, we address the design of the online community to best facilitate this interaction. Our main contribution is the rationale and design of the system, which can easily be extended to build a general eLearning framework.