John W. Roach

Improved Visual Design for Graphics Display

The principles of good visual design used in advertising can help programmers design effective computer displays that will substantially improve the man-machine interface.

A theoretical analysis of conjunctive-goal problems

Abstract Region analysis is a new technique for analyzing search problems by applying graph theory to problem state spaces. The analysis here is of search problems, not search algorithms; analyzing problems and classes of problems lets us understand the underlying structure and inherent complexity of those problems. The analysis technique is demonstrated in the domain of robot planning problems. Region analysis of conjunctive-goal planning problems gives us a characterization of subgoal interactions that is independent of the problem representation. We give a formal characterization of nonlinear planning problems, and show that nonlinearity is a weak characterization of the difficulty in planning problems.

An expert system for information on pharmacology and drug interactions

Pharmacological information has been organized and encoded in rules and frames for systematic retrieval. This includes: delineation, definition, and hierarchical subdivision of mechanisms responsible for drug interactions; division of pharmacological agents into a hierarchy of subclasses to allow for defining interacting drugs by classes as well as by specific agents; correlation of drug classes and specific drugs with mechanisms by which they may be involved in drug interactions. This information, accessible through a natural language-like and menu driven interface, allows clinicians to know what may happen when two drugs are used together, why, what can be done to alleviate detrimental interactions, and what related drugs may also be involved in similar interactions.

A theory of dialogue structures to help manage human-computer interaction

The authors hypothesize the human-computer interaction can be significantly improved by using human-human communication protocols at the interface. These human communication principles are presented for a system built as a natural-language interface to an airline information and reservation system called simulated airline reservation agent (SARA). In particular, they present an extension to human communication theory that makes it possible to create a natural-language interface using human communication principles. Particular attention is given to the use of metacommunication to help manage the shared communication context. The current implementation can parse and generate >5000 surface versions of a single underlying request content, which can help the interface infer some of the users goals and intentions. It is concluded that this technology can be used as a front end for any task domain, yielding much of the full expressiveness of English. >

An expert system for helping apple growers

Abstract Expert systems provide a technology that can help farmers run their businesses economically by using computer programs that encode expert-level knowledge. This paper reports the construction of an expert system, POMME, to help apple growers manage their orchards. POMME advises growers about when and what to spray on their apples to avoid infestations. The system also provides advice regarding treatment of winter injuries, drought control and multiple insect problems. The knowledge structures employed in the construction of the expert system are explained, and some sample interactions are provided. A model of the apple scab disease cycle is incorporated into POMME to give the system a more fundamental reasoning capability than available from the use of infection tables. Extension experts who have run many trial cases on the system have approved its performance.

Spherical dual images: A 3D representation method for solid objects that combines dual space and Gaussian spheres

Three-dimensional object representation significantly impacts computations for manipulation, spatial reasoning and vision. This paper introduces a technique called the spherical dual image, derived from Gaussian sphere and dual space concepts. This representation technique will be defined and a number of its properties will be proven, leading to a reconstruction algorithm for convex and concave polyhedra. Finally, the application of this representation for selecting grasping points to manipulate a polyhedron is discussed.

Model-based object recognition using a large-field passive tactile sensor

The results of a model-driven touch sensor recognition experiment are reported. The touch sensor used is a large-field tactile array. Object features appropriate for touch sensor recognition are extracted from a geometric model of an object, and a dual spherical image is formed. Both geometric and dynamic features are used to identify objects and their position and orientation on the touch sensor. Experiments show that geometric features extracted from the model are effective but that dynamic features must be determined empirically. Correct object identification rates, even for very similar objects, exceed 90%, a success rate much higher than would have been expected from only two-dimensional contact patterns. The position and orientation of objects, once identified, are very reliable. The authors conclude that large-field tactile sensors could prove useful in the automatic palletizing problem when object models (from a computer-aided design system, for example) can be utilized. >

Representing and using metacommunication to control speakers' relationships in natural-language dialogue

Abstract This paper is a report on a new theory and representation of dialogue, called Dialogue Structures. One of the marks of intelligent behavior among humans is the ability to use metaknowledge for making decisions. When two interactants engage in a dialogue, one necessary job is to use metacommunication to manage the relationship between the interactants. We identify and represent structural patterns that provide metaknowledge about the relationship of the interactants, also providing the usual representation of the content of natural language utterances. This paper presents an analysis “by hand” applying the theory to actual dialogues between human speakers. It explains a working program that implements the theory and presents dialogues produced by human users interacting with the program. The theory is so robust that, as a by-product, it interprets indirect requests correctly.

Strategies of Interactive File Search

An experiment was designed to evaluate strategies of interactive file search. Five computerized search procedures were studied to evaluate selection frequency and search efficiency. These search procedures were: scrolling, paging, string search, absolute line movement, and relative line movement. Search strategies were assessed with respect to five independent variables that were manipulated with a mixed-factor, factorial design. These independent variables were: file type, file length, window size, target type, and subject experience. The results indicated that file length, subject experience, and window size were the salient factors of file search. Differences between expert and novice users, as well as, one-line and multi-line windows were discussed with regard to file search performance.

Representing Polyhedra: Faces Are Better than Vertices

In this paper, we investigate the reconstruction of planar-faced polyhedra given their spherical dual representation. We prove that the spherical dual representation is unambiguous for all genus 0 polyhedra and that a genus 0 polyhedron can be uniquely reconstructed in polynomial time. We also prove that when the degree of spherical dual representation is at most four, the representation is unambiguous for polyhedra of any genus.