Icons are normally defined as symbolic objects used in computer systems to communicate possible actions nonverbally. This paper describes the author’s approach to a general theory of an iconic algebra. He constructs the algebra from a number of iconic operators that operate on generalized, dual-representation icons. This approach differs from the familiar icon system used, for example, in the Macintosh. The author has made an important step toward a more general iconic language and should be rewarded for advancing beyond the average level.

Chang defines a general icon as a dual representation of an object, with a logical part (representing the meaning of the icon), and a physical part (representing its image). General icons are used to describe formal icon systems as five-tuples that consist of a set of logical objects, a set of physical objects, and a finite set of icon names along with their root icon name. The tuple also includes a set of rules that define the icons in terms of the logical and physical objects. The icon system is hierarchical and the algebra based upon it has a fairly large number of useful operators. The paper is rich with illustrations, which makes it easy to read and understand.

My overall view of this research paper, which takes an original approach, is positive. It might, however, be difficult for an end user to understand the general hierarchical structure of a single icon system unless its structure is visually displayed. Also, I question whether some of the illustrations (e.g., example 1, the image database) really correspond to icons.