Transformation of Geographical Information into Linguistic Sentences: Two Case Studies
Abstract
Information can be communicated at three levels, i.e., the syntactic, the semantic and the pragmatic level. Since the pragmatic level is related to the application of the data, transformation of information from the lower level representations to the pragmatic level can reduce the amount of information to be processed by the receiver and speed up the perception of the information. For example, assume a display showing a submarines position relative the terrain surface. Since the distance along six axes must be evaluated, i.e., ahead, backwards, port, starboard, up and down, the presentation of the numerical values along the axes must be carefully designed in order to communicate the information unambiguous to a human operator. The first part of the present paper shows how fuzzy logic can be used to design the kind of instrument considered. The second part of the paper shows how the zone of safety around the submarine, the uncertainties of the terrain model and the submarines position can be modelled as fuzzy regions and how the topological relations between this kind of regions can be described in natural language sentences. Based on a perception study we found that the perception of long distance is related to the frame of the map. The experiment did show that people associate the term long distance to two points when the distance between them is 40% of their maximal distance in the display. From this experiment we have designed an instrument to communicate the degree of risk so that a bar gets length 40% of its maximal length when the risk is on the boarder between low and high. From the knowledge of the speed of the submarine and the tactical assessments the degree of risk is modelled as a fuzzy membership function. In that way the distance from the vessel to the terrain surface can be visualized as the degree of risk along the six axes considered.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2004
- Accession Number
- ADA427991
Entities
People
- Jan T. Bjorke
Organizations
- Norwegian Defence Research Establishment