<p><p>Films and novels effectively convey intriguing stories, powerful emotions, and meaningful messages to their audiences. Telling interactive stories in a virtual environment seems a natural progression of the narrative. Users find virtual environments more engaging when they perceive that they have agency within those environments. The greater the sense of freedom they have over choosing and executing their own actions, the greater their sense of agency will be. However, in order to maintain the coherence of their stories, current attempts at interactive narrative environments often limit a users sense of agency by restricting his ability to affect critical elements of the story. The process of mediation is designed to give users as great a sense of agency in an unfolding narrative as possible while still maintaining the narrative's coherence and goals. This is accomplished by making the system, user, and author collaborators in the production of the storyline. This collaboration takes the form of a mediation system constantly rewriting the narrative within the confines of the author's goals as the user interacts with characters and objects in the virtual environment.</p><p>Mediation assumes that an effective narrative storyline can be modeled by a fully ordered series of actions (know as a plan) performed by one or more virtual characters in a virtual environment. A mediation system is composed of three primary components: a speculative planner, a decision cache data structure, and an execution monitor. The speculative planner is constantly analyzing the storyline to determine what actions a user could perform that would prevent the storyline from reaching its end. For each such action it utilizes a narrative planner to determine if the storyline can be rewritten around the action or if the action must be prevented. One way of realistically preventing an action is modeled by failure modes. Failure modes are alternative actions that can be substituted by the system when necessary for user-attempted actions.</p><p>The decisions of the speculative planner are stored in the decision cache data structure that is used by the execution monitor. The execution monitor observes users in the virtual environment and the actions they perform. If any user attempts an action in the decision cache, the execution monitor alerts the speculative planner and takes preventive action if necessary.</p><p>Mediation is a prime candidate for use in narrative environments that require a great deal of user interaction and freedom. Most notable are entertainment and educational systems. More generally, mediation concepts can be applied to many varying collaborative application environments, such as on-screen agents that advise or assist users in the achievement of goals. Mediation frees users from the limitations of a system's author's ability to predict all combinations of actions a user may wish to perform in a virtual environment.</p><p>In this work we describe a prototype of the execution monitor component of mediation that has been implemented in Mimesis, a virtual environment architecture designed for interactive narrative [37].</p><P>
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-20010803-153815 |
| Date | 03 August 2001 |
| Creators | Saretto, Cesare John |
| Contributors | Dr. R. Micahel Young, Dr. Peter Wurman, Dr. Robert St. Amant |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-20010803-153815 |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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