Currently I am a doctoral candidate in the Department of Spatial Information Science and Engineering under the guidance of Dr. Michael Worboys. My expected graduation date is December 2013, and I am looking for an academic teaching and/or research position starting immediately.
Please see my curriculum vitae or profile on LinkedIn.
See my alternate site for more information about prior research and publications. My doctoral thesis topic summary is as follows:
Qualitative Models for Goal-directed Indoor Navigation
Formal models of indoor space for reasoning about pedestrian navigation tasks should capture key static and dynamic properties
and relationships between agents, objects, and indoor spaces, and provide an effective framework for reasoning about change. Of particular interest are changes in properties or relationships that affect an agentís ability to carry out a goal directed navigation task. This thesis presents a framework for formally representing indoor environments, the events that occur in them, and their effects on the topological properties and relationships between indoor spaces and agents. The main goal is to provide a computational foundation for qualitative spatio-temporal reasoning about indoor pedestrian navigation by modeling the effects of key indoor events on agent behaviors and relationships in indoor environments. The framework has three major components:
- Indoor Navigation Ontology which formally captures the typology of agents, objects, places and agent actions and events that are utilized in the indoor bigraph model and indoor event calculus. It also integrates information from existing quantitative data models such as Building Information Models (BIMs).
- Indoor Bigraph Model, which provides formal algebraic specifications of indoor environments that independently represent agent and place locality (e.g., building hierarchies) and connectivity (e.g., path based navigation graphs). Bigraph composition and joining operations can be used to adjust the granularity of scenes and to compose partial scenes to provide additional context.
- Indoor Event Calculus, which provides a logic-based formalism for representing the effects of indoor space events on key indoor relationships. By defining indoor fluents IN and LINKED with associated events INTO, LINK, and UNLINK and appropriate effect axioms we can construct narratives about indoor navigation tasks as potential sequences of events and their consequences in indoor environments. For example, given an agentís starting situation and a particular goal-directed navigation task we can determine potential sequences of events that would lead to satisfying her goal (e.g., if a fire occurs in the building, how can she straightforwardly reach an exit?).
A case study is provided applying the framework to the US Veteran's Administration Clinic domain is provided which illustrates that the framework can be used to generate navigation plans to assist both patients and medical staff to find appropriate goal-directed indoor navigation routes inside clinics.
- Walton, L. & Worboys, M. (2013). An Event Calculus for Indoor Navigation. 21st ACM SIGSPATIAL In-ternational Conference on Advances in Geographic Information Systems. Orlando, FL. Nov 5-8, 2013. (Submitted).
- Walton, L. & Worboys, M. (2012). A Qualitative Bigraph Model for Indoor Space. Proceedings of the 7th International Conference on Geographic Information Science Columbus, OH. Sept 18-21, 2012. (GIScience 2012). (pdf)
- Giudice, N.A., Walton, L.A., & M. Worboys. (2010). The informatics of indoor and outdoor space:
A research agenda. Second ACM SIGSPATIAL International Workshop on Indoor Spatial Awareness (ISA 2010),
November, San Jose, CA. 2010.
- Walton, L. & M. Worboys. (2009). An Algebraic Approach to Image Schemas for Geographic Space.
Proceedings of the 9th International Conference on Spatial Information Theory (COSIT), France, September 2009.
pp. 357-370, Lecture Notes in Computer Science, Vol. 5756, ISBN 978-3-642-03831-0, Springer.
Locus enim est principum generationis rerum (For place is the origin of things) - Roger Bacon
Lisa Ann Walton
Graduate Research Assistant
Department of Spatial Information Science and Engineering
School of Computing and Information Science
University of Maine, Orono, ME. 04469
lisa DOT walton AT maine DOT edu
You can also find me on Academia.edu, LinkedIn, Facebook, or Twitter.