Browsing by Author "Brad Mehlenbacher, Committee Member"

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A Computational Model of Narrative Generation for Surprise Arousal
(2009-07-28) Bae, Byung Chull; R. Michael Young, Committee Chair; James C. Lester, Committee Member; Brad Mehlenbacher, Committee Member; Robert Rodman, Committee Member
This dissertation describes work to develop a planning-based computational model of narrative generation designed to elicit surprise in the mind of a reader. To this end, my approach makes use of two narrative devices Ã¢â‚¬â€œ flashback and foreshadowing. While surprise plays an important role for attention focusing, learning, and creativity, little effort has been made to build a computational framework for surprise arousal in narrative. In my computational model, flashback provides a backstory to explain what causes a surprising outcome, while foreshadowing gives hints about the surprise before it occurs. In this work I focus on the arousal of surprise emotion as a cognitive response which is based on a reader's cognitive appraisal of a given situation. In this dissertation I present Prevoyant, a planning-based computational model of surprise arousal in narrative generation, and analyze the effectiveness of Prevoyant. To build a computational model of the unexpectedness in surprise, I adopt a cognitive model of surprise based on expectation failure. There are two contributions made by this dissertation. First, I present a computational framework for narrative generation designed to elicit surprise. The approach makes use of a two-tier model of narrative and draws on Structural Affect Theory, which claims that a readerÃ¢â‚¬â„¢s emotions such as surprise or suspense are closely related to narrative structure. Second, I present a methodology to evaluate surprise in narrative generation using a planning-based approach based on the cognitive model of surprise causes. The results of the experiments that I conducted show strong support that my system effectively generates a discourse structure for surprise arousal in narrative.
Effects of Study Modality and Study Order on Learning Braille and Other Haptic Alphabets Used by Blind Persons
(2005-12-02) Mroczka, Mary Ann; Brad Mehlenbacher, Committee Member; James W. Kalat, Committee Member; Michael S. Wogalter, Committee Co-Chair; Slater E. Newman, Committee Co-Chair
Braille is the alphabet predominantly used today for total communication by blind persons; yet, its difficulty to learn prevents some from using it. This experiment compared learning of three alphabets used by blind persons, Braille, Moon and Fishburne. The effects of study modality (visual, haptic) and study order (random, alphabetical) were also investigated. Participants were given four study-test sequences to learn the names for each of the 26 symbols of one of the three alphabets. On test trials, all participants were tested haptically in different random orders. Results showed main effects for alphabet, study modality, trials and an interaction between trials and alphabet. Moon was easier to learn than Braille, which was easier to learn than the Fishburne alphabet. Visual study facilitated learning only with the Moon alphabet. Results are interpreted in terms of McGuire's (1961) three proposed processes involved in paired-associate learning: stimulus discrimination, associative learning, and response learning. Some implications for training are also discussed.
Examining and Explaining the Effects of Non-Iconic Conformal Features in Advanced Head-up Displays on Pilot Performance
(2009-04-15) Kim, Sang-Hwan; David B. Kaber, Committee Chair; Robert St. Amant, Committee Member; Eric Wiebe, Committee Member; Brad Mehlenbacher, Committee Member; Nancy Currie, Committee Member
The primary objective of this study was to assess the impact of Synthetic Vision System (SVS) and Enhanced Vision System (EVS) depictions of terrain features on pilot performance when displayed in an advanced head-up display (HUD) during various phases of a landing approach under instrument meteorological conditions (IMCs). SVS is a display system that presents terrain features using a wireframe grid rendered polygons by integrating terrain databases with a global positioning system. EVS displays present an actual out-of-cockpit view using a forward looking infrared camera. In the experiment as part of this study, video stimuli presenting varied HUD configurations were pre-recorded using a high-fidelity flight simulator at NASA Langley and presented to eight pilots later in a lab environment. The HUD videos from the high-fidelity simulator were combined with out-of-cockpit views from a lab simulator. The flight scenario consisted of an approach and landing on a runway (Reno, Nevada International Airport (KRNO), 16R (right)) under IMC. Each pilot completed eight trials based on a within-subjects experimental design and one additional trial to collect verbal protocols on specific display feature use. The independent variables included four display configurations (baseline, SVS-only, EVS-only, and a combination of SVS and EVS features) and two visibility conditions (IMC-day versus IMC-night). Every display configuration included tunnel features (highway-in-the sky) showing the designated flight path. The experiment involved observing pilot performance in four segments during the approach and landing. Dependent variables included flight path control performance, pilot SA, workload, and subjective preferences. Flight path control performance was determined based on pilot errors in tracking a flight path marker in the pre-recorded videos with a super-imposed cursor using test pilots yoke controls. Pilot situation awareness (SA) was measured using SAGAT (the Situation Awareness Global Assessment Technique) in order to evaluate pilot perception, comprehension, and projection for three types of pilot SA (spatial, system, and task awareness). Workload measures were recorded using the NASA-TLX (Task Load Index) and heart-rate. In order to develop explanations of pilot behavior under the various HUD conditions, a video record of the additional test trial was reviewed by each subject using a verbal protocol analysis and semi-structured interview. Results revealed SVS to support overall pilot SA but to degrade flight path control performance due to confusion of visual features, EVS caused pilots to focus on path control but decreased System awareness because of visual distractions of some imagery. The combination of SVS and EVS features generated offsetting effects; however there were decrements in performance in the final landing phase due to clutter effects. In general, display configurations did not affect spatial awareness but pilot awareness of system information was impacted. The IMC-day condition produced worse flight performance than night flight due to the low visual saliency of HUD imagery in daylight. Flight performance was not different among phases of flight but different levels and types of pilot SA were affected by segment. Because the main task in the study was the tracking task, results did not reveal differences of conditions in terms of workload measures. Interestingly, patterns of pilot preference for displays did not match with the results of objective performance and SA measures. Pilots gave higher ratings of SA support and safety for the SVS and EVS displays with the lowest ratings going to the combination. Ratings on annoyance increased with increases in display visual content. The verbal protocol analysis yielded sequential and non-sequential lists of pilot tasks and behaviors and critical pilot comments. The analysis also identified the required information and alternative methods of performance for specific flight tasks in the scenario. This analysis was used to explain the experimental results and describe pilot behaviors with the SVS and EVS displays in the flight scenario. This study assessed advanced HUD feature effects on pilot performance, using an elaborate SAGAT method for measuring pilot SA, and developed a CTA for interpreting experimental results. Further studies need to be conducted to evaluate the advanced HUDs under various flight situations using a more realistic flight simulator as a basis for optimal design. In addition, cognitive model of pilot behavior based on CTA needs to be developed for predicting performance and SA implications of HUD design.
Narrative Planning: Balancing Plot and Character
(2004-10-21) Riedl, Mark Owen; R. Michael Young, Committee Chair; James Lester, Committee Member; Jon Doyle, Committee Member; Michael Capps, Committee Member; Brad Mehlenbacher, Committee Member
The ability to generate narrative is of importance to computer systems that wish to use story effectively for a wide range of contexts ranging from entertainment to training and education. The typical approach for incorporating narrative into a computer system is for system builders to script the narrative features at design time. A central limitation of this pre-scripting approach is its lack of flexibility -- such systems cannot adapt the story to the user's interests, preferences, or abilities. The alternative approach is for the computer systems themselves to generate narrative that is fully adapted to the user at run time. A central challenge for systems that generate their own narrative elements is to create narratives that are readily understood as such by their users. I define two properties of narrative — plot coherence and character believability — which play a role in the success of a narrative in terms of the ability of the narrative's audience to comprehend its structure. Plot coherence is the perception by the audience that the main events of a story have meaning and relevance to the outcome of the story. Character believability is the perception by the audience that the actions performed by characters are motivated by their beliefs, desires, and traits. In this dissertation, I explore the use of search-based planning as a technique for generating stories that demonstrate both strong plot coherence and strong character believability. To that end, the dissertation makes three central contributions. First, I describe an extension to search-based planning that reasons about character intentions by identifying possible character goals that explain their actions in a plan and creates plan structure that explains why those characters commit to their goals. Second, I describe how a character personality model can be incorporated into planning in a way that guides the planner to choose consistent character behavior without strictly preventing characters from acting 'out of character' when necessary. Finally, I present an open-world planning algorithm that extends the capabilities of conventional planning algorithms in order to support a process of story creation modeled after the process of dramatic authoring used by human authors. This open-world planning approach enables a story planner not only to search for a sequence of character actions to achieve a set of goals, but also to search for a possible world in which the story can effectively be set.
Not Now, Maybe Later, and Often Not at All: Situational, Institutional, Dispositional, Epistemological, and Technological Barriers to Business-Based Online Training Courses
(2004-04-16) Roberts, Linda Enders; Darryl McGraw, Committee Member; David Rieder, Committee Member; Brad Mehlenbacher, Committee Member; Paula Berardinelli, Committee Chair
The purpose of the research was to determine whether the situational, institutional, dispositional, epistemological, and technological barriers that affect attrition in distance education apply to the business-based distance training arena. Although reports about distance training students indicate that attrition from distance training is a significant issue, the results from this study find that 90 percent of the business professionals who answered this survey that have taken business-based e-learning courses are not discontinuing their e-learning courses. This finding contradicts many published articles. The free-form comments written by the online learners who answered this survey provided some hints as to what may be keeping these business professionals from abandoning their e-learning courses. The respondents to this study acknowledge that interaction with other learners and with course facilitators, chunking of courses and curricula into appropriate sized pieces, technical support, good course design, and incentives to reach course or curriculum completion have kept them online.
The Use of Cues in Multimedia Instructions in Technology as a way to Reduce Cognitive Load
(2009-04-16) Roberts, William Edward; Eric N. Wiebe, Committee Chair; Brad Mehlenbacher, Committee Member; V. William Deluca, Committee Member; William Jame Haynie III, Committee Member
This study was designed to address cognitive overload issues through the use of visual cueing as a means to enhance learning. While there has been significant research such as use of color for cueing to address many of the cited problems, there are missing elements in this research that could go a long way toward designing more effective solutions and teaching methods for Technology Education students. One aspect that is missing is a better understanding of how color cueing and narration interact with various aspects of information overload, split attention effect, and overall instructional difficulty. When teaching technical topics to a technical or non-technical audience using multimedia instructions or tutorials, there is a problem of information overload when using these methods of delivery. Without the proper testing and methods for designing these types of presentation, the students or the audience the instructor plans to present this information to may likely experience cognitive overload, reducing the effectiveness of the instructions and tutorials. Cognitive overload is the result of excessive demands made on the cognitive processes, in memory particular. The research was also designed to move beyond theory and to research hands-on instructional activities with typical students to prove that certain multimedia interventions reduce cognitive load and make learning more efficient when presenting technical information. The principal research uses two rating scale assessment techniques: the SSI and NASA-Task Load Index (TLX), to assess levels of cognitive load. Previous research demonstrated that the SSI and TLX had different sensitivities to cognitive load. The research adds to the existing research base, address some of these missing elements, and gain a better understanding of how to address the problems that have been presented above specific to Technology Education students, but equally relevant to other subject matter. Visual cueing shows promise as a means to reduce cognitive overload and enhance learning.