In spite of the increasing sophistication and power of commercial spreadsheetpackages, we still lack a formal theory of spreadsheets and a methodology thataids their construction and maintenance. Using a new functional relationallanguage, this paper identifies four principal components that...

In spite of the increasing sophistication and power of commercial spreadsheetpackages, we still lack a formal theory or a methodology to support the constructionand maintenance of spreadsheet models. Using a dual logical/physicalperspective, we identify four principal components that...

Belief updating schemes in artificial intelligence may be viewed as threedimensional languages, consisting of a syntax (e.g. probabilities or certaintyfactors), a calculus (e.g. Bayesian or CF combination rules), and a semantics(i.e. cognitive interpretations of competing formalisms). This paper...

Uncertain facts and inexact rules can be represented andprocessed in standard Prolog through meta-interpretation. Thisrequires the specification of appropriate parsers and beliefcalculi. We present a meta-interpreter that takes a rule-basedbelief calculus as an external variable. The...

One of the key challenges in designing expert systems is a credible representationof uncertainty and partial belief. During the past decade, a number ofrule-based belief languages were proposed and implemented in applied systems.Due to their quasi-probabilistic nature, the external validity of...

The problem of modeling uncertainty and inexact reasoning inrule-based expert systems is challenging on nonnative as well oncognitive grounds. First, the modular structure of the rule-basedarchitecture does not lend itself to standard Bayesianinference techniques. Second, there is no consensus...

Rule based expert systems deal with inexact reasoning through avariety of quasi-probabilistic methods, including the widely usedcertainty factors (CF) and subjective Bayesian (SB) models, versionsof which are implemented in many commercial expert systemshells. Previous research established that...

Rule-based expert systems must deal with uncertain data,subjective expert opinions, and inaccurate decision rules. Computer scientistsand psychologists have proposed and implemented a number of belief languages widely used in applied systems, and their normative validity is clearly an important...