my research interersts...
My primary research interest is on Spatial Cognition and its application to Wayfinding in a multimodal urban environment. Multimodality in this context is defined as the combination of different means of transportation for getting to a certain destination. The main focus of my PhD dissertation is on Landmarks and the definition of their characteristics and attributes with respect to wayfinding tasks in urban environments.
Landmarks and their saliency is not an exact science. Many different factors influence the perception of geo-spatial objects as "prominent" or "salient" features. These mental processes that people employ to assess the "landmarkedness" of geo-spatial objects are not totally understood yet. Therefore, the largest problem lies in finding meaningful ways of quantifying the process so that it can be modeled and implemented in an information system.
In the first part of my thesis, I propose a conceptual framework for assessing the salience of landmarks for navigation. Landmark salience is derived as a result of the observer's point of view, both physical and cognitive, the surrounding environment, and the objects contained therein. This is in contrast to the currently held view that salience is an inherent property of some spatial feature. Salience, in our approach, is expressed as a three-valued Saliency Vector. The components that determine this vector are Perceptual Salience, which defines the exogenous (or passive) potential of an object or region for acquisition of attention, Cognitive Salience, which is an endogenous (or active) mode of orienting attention, triggered by informative cues providing advance information about the target location, and Contextual Salience, which is tightly coupled to modality and task to be performed. This separation between voluntary and involuntary direction of attention in dependence of the context allows defining a framework that accounts for the interaction between observer, environment, and landmark. I identify the low-level factors that contribute to each type of salience and suggest a probabilistic approach for their integration. The conceptual part of the thesis discusses implications, considers restrictions, and explores the scope of the framework.
On the base of this framework, I am currently working on a prototype implementation for the assessment of landmark saliency. The prototype application includes a refined computational model and will serve as test-bed for future research. The conceptual framework defines the overall structure of the saliency assessment, but leaves open how the low-level components of saliency (e.g., degree of recognition, task-based context) are derived. The prototype application will provide support in answering these open questions. Refining the computational model and the prototype application will also help answering questions related to usability and performance, and provide insight into technical and infrastructural questions, such as feasibility and acquisition of appropriate data.
A very important question in this context is concerned with the evaluation of the framework. I will use the prototype application for evaluating the framework and I will perform the evaluation in two steps, namely 1) Verification and 2) Validation. I understand the process of verifying the framework as confirmation by examination and provision of objective evidence that specified requirements have been fulfilled. Verification will answer questions related to inner correctness and performance of the prototype. Validation, on the other hand, is understood as the process of ground-truthing, and will determine if the framework can be properly applied as intended. Verification will answer questions related to performance in real world scenarios and fine-tuning with respect to human performance. Successful evaluation of the prototype is crucial for further research and will have to be performed accordingly.
Thesis work is still in progress, but will hopefully come to an end soon. So please check back often...
Last updated on: April 18, 2007.