Browsing by Author "Dr. James Lester, Committee Member"

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Coglaborate - An Environment For Collaborative Cognitive Modeling
(2009-11-24) Cornel, Reuben Francis; Dr. James Lester, Committee Member; Dr. Christopher Healey, Committee Member; Dr. Robert St. Amant, Committee Chair
Cognitive scientists who build computational models of their work, as exemplified by the ACT-R and Soar research communities, have limited means of sharing knowledge: annual conferences and workshops, summer schools, and model code distributed via Web sites. The consequence is that results obtained by different groups are scattered across the Internet, making it difficult for researchers to obtain a comprehensive view of cognitive modeling research. The goal of my project is to develop a collaborative modeling environment for cognitive scientists in which they can develop and share models. The current system supports collaboration by providing a structured representation for ACT-R cognitive models using frames. The rationale for providing a structured representation for cognitive models is two-fold: it not only provides a mechanism for sharing models (i.e. via consistent APIs); it also enables the application of analytical techniques to cognitive models. As a proof of concept for the approach, a medium-scale modeling application has been developed, integrating an extension of ACT-R developed elsewhere, to solve synonym crossword puzzles.
Image Processing Substrate to Assist Cognitive Models Interact with Dynamic Environments
(2003-08-18) Rajyaguru, Sameer Rajendra; Dr. R. Michael Young, Committee Member; Dr. James Lester, Committee Member; Dr. Robert St. Amant, Committee Chair
Cognitive models have typically dealt with artificial environments or real environments that are simple. This is because the cognitive models either use indirect approaches to interact with environments, or in cases where they adopt direct approaches to interact, the image processing substrate is incapable of dealing with complex interfaces. However, it is imperative for cognitive models to interact directly with complex environments in order to ascertain the reliability of the underlying cognition theory. The image processing substrate proposed in this thesis overcomes the above-mentioned limitations and enables cognitive models to interact directly with complex environments. This is due to the functionality provided by the substrate that facilitates representation and identification of complex visual patterns. As part of the research work for this thesis, the substrate has been customized to process two interfaces and a cognitive model has also been built on the ACT-R cognitive architecture that uses the proposed substrate to control a driving game environment.
An Intelligent Cinematic Camera Planning System for Dynamic Narratives
(2004-01-08) Jhala, Arnav Harish; Dr. R Michael Young, Committee Chair; Dr. James Lester, Committee Member; Dr. Robert StAmant, Committee Member
This thesis presents a framework for automatic generation of cinematic discourse of a dynamic story. The motivation of this research is provided by the need for more expressive camera control in the current dynamic story generation systems and the lack of formal research in the area of visual discourse processing/generation systems. Film directors and cinematographers have developed effective visual storytelling techniques. They have also articulated various rules for conveying the story to the viewer. The stereotypical ways of filming shot sequences are termed as Idioms. This thesis begins to formalize film idioms as plan operators, augmented with the intentional goals of the director, that represent communicative acts analogus to speech acts used in traditional natural language discourse planning systems. Discourse processing/planning systems have focused on generation of natural language discourse. This is an attempt to extend this research to the generation of visual discourse. The main questions that are addressed in this thesis are: • How does a visual communicative act change the model of the viewer and how can this be encoded in a formalism? • How can the presentation of a scene/shot relate to the actions taking place in the story world and the information being conveyed to the viewer about the story world? • What are the syntax and semantics of the visual medium of communication as they are specified by legal plan structures? I present a study of film idioms and their formalization as plan operators followed by a formal description of the viewer model used by the system. Next, I discuss the representation of the story world plan that is communicated to the viewer by the discourse planner and a formal definition of the extended discourse planning algorithm. Finally, a sample scenario for the communicative plan generated by the discourse planner written in Lisp and executed on the Unreal Tournament 2003(UT) game engine used as a visualizer.
Intelligent Context-Sensitive Help for Dynamic User and Environment Contexts
(2004-10-29) Ramachandran, Ashwin; Dr. R. Michael Young, Committee Chair; Dr. James Lester, Committee Member; Dr. Robert St. Amant, Committee Member
The problem of providing help for complex application interfaces has been a source of interest for a number of researcher efforts. As the computational power of computers increases, typical applications not only increase in functionality but also in the degree of interaction with the computational environment in which they reside. There are powerful software tools available today used for both specialized and non-specialized tasks that are often used by novice users who attempt tasks without significant training or knowledge of the application's interface. These kinds of applications are diverse and complicated in the variety of functionality they provide, often interacting with other applications on the user's system. With current platforms (Windows, Macintosh, Linux etc) providing extensive multi-tasking facilities, interaction with these applications is sometimes affected by the context of the environment itself (e.g., application windows being minimized, maximized or obscured by those of other applications). The interdependencies between applications and their environments increase the difficulty of providing effective context-sensitive help when building an application's help documentation. The purpose of this research is to create an Intelligent Help System, which incorporates these interactions and affecting factors when providing help. The SmartAidè system, which was developed as part of this effort, works on the premise that the user has a goal when interacting with the application. This document will provide a detailed overview of the architecture of the system along with the underlying design decisions. The system was then evaluated against traditional application help documentation to test its effectiveness. The results and analysis of this evaluation have been enumerated.
A New Heuristic for the Hamiltonian Circuit Problem
(2008-12-22) Narayanasamy, Prabhu; Dr. Carla Savage, Committee Member; Dr. Matthias Stallmann, Committee Chair; Dr. James Lester, Committee Member
In this research work, we have discussed a new heuristic for the Hamiltonian circuit problem. Our heuristic initially builds a small cycle in the given graph and incrementally expands the cycle by adding shorter cycles to it. We added features to our base heuristic to deal with the problems encountered during preliminary experiments. Most of our efforts were directed at cubic Cayley graphs but we also considered random, knight tour and geometric graphs. Our experimental results were mixed. In some but not all cases the enhancements improved performance. Runtime of our heuristic was generally not competitive with existing heuristics but this may be due to inefficient implementation. However, our experiments against geometric graphs were very successful and the performance was better than the Hertelâ€™s SCHA algorithm, even in terms of runtime.
Strategic Deception in Agents
(2004-08-02) Christian, David Benjamin; Dr. James Lester, Committee Member; Dr. R. Michael Young, Committee Chair; Dr. Munindar Singh, Committee Member
Despite its negative ethical connotations, deception is a useful tool for human social interaction, and plays an important role in the process of creating the stories that pervade our popular culture. In this paper, we describe the deception planner, an implementation of a model of strategic deception. Strategic deception is deception performed in order to achieve or enable some higher goal, as opposed to deception that is performed for the sake of deceiving, or for an unstated purpose. Given a model of a deceiver holding ulterior goals, a model of the goals and abilities of a target agent to be deceived, and a model of the relevant pieces of the world, the deception planner generates a set of statements about the current world state which may be either true or false. Those statements are communicated to the target agent, which updates its world state to reflect this new information. The target then performs planning to achieve its own goals, with no knowledge of the deceiver's goals. If the deception planner generates an successful set of statements, the target agent will create a plan that achieves the deceiver's ulterior goals despite no knowledge of those goals. To find the set of statements that will generate this desired behavior from the target agent, the deception planner models the target agent's planning process. The deception planner searches for a plan that achieves the target agent's goals as well as the deceiver's ulterior goals. When such a plan is found, it is labeled the candidate plan, and the deceiver gives the target agent enough (dis)information so that, given the target agent's knowledge of the world, she can generate that plan. The candidate plan may depend on lies, chosen by the deception planner. The planner ensures that any lies told are not discovered before the target executes enough of the plan to achieve the ulterior goals. Once a candidate plan has been found, the deception planner the finds and counters competing plans. Competing plans are plan that achieve the target's goals but not the deceiver's goals, but are of equivalent or better quality than the candidate plan according to some metric shared by the target and deceiving agent. Because they are of the same or better quality, the target agent may choose a competing plan instead of the candidate plan. A competing plan is countered by undermining through lying a belief that is necessary for that plan to be executable. Although the deception planner fits within a body of work on agent deception, the goal of this algorithm is unique in its focus on causing a target agent to act in order to achieve a deceiver's goals, and in its utilization of a model of the goals and planning abilities of the target agent to that end.
Telescope: A Multivariate Visualization Framework in Support of the Development of a Perceptual Visualization Hierarchy
(2008-01-03) Whitehorne, Andrew Ennis; Dr. Robert Fornaro, Committee Member; Dr. James Lester, Committee Member; Dr. Christopher G. Healey, Committee Chair
Web Information Retrieval using Web Document Structures.
(2004-01-08) Namjoshi, Nihar; Dr. Robert StAmant, Committee Chair; Dr. Christopher Healey, Committee Member; Dr. James Lester, Committee Member
Information domains such as the World Wide Web have enormous information content. The task of extracting information relevant to a particular topic, or trying to predict what sort of information a user is seeking is not a trivial task. For a user, finding information relevant to a particular area of interest can be inconvenient and sometimes frustrating as well. Studies have shown that when users are faced with such a task, they may get easily bored and thus leave a Web site. Traditional Information Retrieval techniques rely on measures such as the frequency of a word in a given document, or the hyperlink connectivity of that particular web document. This approach may not necessarily bring out the important words or terms in a document and thus could be less effective while returning search results for queries. In our approach, we rely not only on the actual text in the document, but we also use the inherent formatting elements in Web pages, derived from the Hyper Text Markup Language (HTML) syntax to support our process of information extraction. We use rules to assign measures to important terms in a document in order to facilitate the relevant Information Extraction. We evaluated our system by asking users to test it and in addition, we compared our results with the results from a conventional search engine.
A Web Services Approach to Generating and Using Plans in Configurable Execution Environments
(2006-03-01) Vernieri, Thomas Michael; Dr. R. Michael Young, Committee Chair; Dr. Dennis Bahler, Committee Member; Dr. James Lester, Committee Member
The computational scope of artificial intelligence in games has traditionally been limited by the processing requirements of the game engine's graphics and physics components. The emerging genre of interactive narrative typically relies upon AI planning systems that perform computation too demanding to integrate into commercial games. This thesis describes Zocalo, a collection of service-oriented applications, in which a planning Web service generates interactive storylines for story-based games and interactive narratives. The interfaces of the planning services allow for usage scenarios ranging from simple to complex. We describe the use of planning services both for run-time construction of narrative plans and for design-time iterative specification of game contents. Zocalo facilitates the execution of plans in commercial game engines with only small modifications to the original games. It provides for the execution of story plans in numerous situations, automatically adjusting the state of the game's environment so that it is compatible with the beginning of the story. The plan execution functionality of Zocalo is intended for gaming environments but can also be applied to other applications in need of narratives.