Path-based and node-based inference in semantic networks

Abstract

Two styles of performing inference in semantic networks are presented and compared.Path-based inference allows an arc or a path of arcs between two given nodes to be inferred from the existence of another specified path between the same two nodes.Path-based inference rules may be written using a binary relational calculus notation.Node-based inference allows a structure of nodes to be inferred from the existence of an instance of a pattern of node structures.Node-based inference rules can be constructed in a semantic network using a variant of a predicate calculus notation.Path-based inference is more efficient, while node-based inference is more general.A method is described of combining the two styles in a single system in order to take advantage of the strengths of each.Applications of path-based inference rules to the representation of the extensional equivalence of intensional concepts, and to the explication of inheritance in hierarchies are sketched.

Predication, fiction, and artificial intelligence

“…Path-based reasoning can be thought of as subconscious reasoning; it is a generalization of the notion of "inheritance" found in many other semantic-network systems (cf. Shapiro, 1978;Srihari, 1981). A belief revision system is a facility for detecting and removing inconsistent beliefs; the SNePS version is based on a form of relevance logic (cf.…”

StaticsTutor: Free Body Diagram Tutor for Problem Framing

“…E.g., Node T (Tweety) is an instance of Node B (Birds). Other inferences such as path-based or node-based have been discussed by Shapiro (1978). …”

SNePS Considered as a Fully Intensional Propositional Semantic Network

“…Nodes that only have arcs pointing to them are considered to be unstructured or at omit. They include: (1) sensory nodes, which-when SNePS is being used to model a mind-represent interfaces with the external world (in the examples that follow, they represent utterances); (2) base nodes, which represent individual concepts and properties; and (3) variable nodes, which represent arbitrary individuals (Fine 1983) (Shapiro 1978;Shapiro & McKay 1980;Mchav & Shapiro 1981;Shapiro, Martins, CEr McKay 1982). For each of the three categories of molecular nodes (structured individuals, atomic propositions, and rules), there are constant nodes of that category and pattern nodes of that category representmg arbitrary entities of that category.…”

“…An ATN parser/generator (Shapiro 1982) [CASSIE can answer the question using the class hierarchy, because, prior to the conversation, an inheritance rule was given to SNePS. The rule says that the CLASS arc is implied by the path consisting of a CLASS arc followed by zero or more occurrences of the two-arc path consisting of the converse SUBCLASS arc followed by the SUPERCLASS arc (Shapiro 1978, Srihari 1981 [This and the next two Inputs are given to establl5h more of the class hierarchy and to make it clear that when <:.4SSII: answers the last question of this session, she is doing both path-based reasoning and node-based reasoning at the same tlme.1 was answered using path-based lnferenclng to deduce that I.ucy and John are people and that Rover is a pet, and node-ba<ed inferencing to Conclude that. therefore, I-ucy and John lo\ e Ro\ er.…”

“…Paths of arcs can be defined, allowing for path-based inference, including property inheritance w.ithin generalization hierarchies (see below; Shapiro 1978, Srihari 1981. All other arc labels are defined by the user, typically at the beginning of an interaction with SNePS.…”