Cheng, Linfu

The subject of this thesis is to study the graphical and data requirements of an ECAD system and propose a database that merges the information into a single cohesive structure. For ECAD applications, traditional database structures pose many limitations and usually ignore graphics aspects altogether. Since graphical information is highly dependent upon the graphics implementation, the international standard, GKS, was used for the foundation of the graphical information. The proposed structure is not intended for direct interface to GKS, but can provide relevant information for GKS through an interface applications program. Electronic design is usually done in a hierarchical manner using components (objects), and relating them to one another through connections. Thus the ECAD database should support this. To reduce redundancies, a network structure was added to minimize duplicated data, thus the name Hierarchical Object Related Network.

The problem of finding optimal paths for a robot navigating in an environment where the position of each obstacle is precisely known has received much attention in the literature, however, the majority of applications problems for a robot would require it to navigate in a completely unknown. This paper focuses on an approach to solving the problem of robot navigation in an unknown, unstructured, two-dimensional environment where the positions of the polygonal obstacles were fixed in time. Few studies have reported on the utilization of an expert system to govern robot motion. This study relied on a knowledge-based expert system that interacted with lower-level procedures to carry out path finding and exploration functions. The expert-system shell used was OPS5 which ran on top of Lisp.