Christopher Menzel

The process specification language (PSL) theory and applications

The PROCESS SPECIFICATION LANGUAGE (PSL) has been designed to facilitate correct and complete exchange of process information among manufacturing systems, such as scheduling, process modeling, process planning, production planning, simulation, project management, work flow, and business-process reengineering. We give an overview of the theories within the PSL ontology, discuss some of the design principles for the ontology, and finish with examples of process specifications that are based on the ontology.

The IDEF Family of Languages

The purpose of this contribution is to serve as a clear introduction to the modeling languages of the three most widely used IDEF methods: IDEFO, IDEF1X, and IDEF3. Each language is presented in turn, beginning with a discussion of the underlying “ontology” the language purports to describe, followed by presentations of the syntax of the language — particularly the notion of a model for the language — and the semantical rules that determine how models are to be interpreted. The level of detail should be sufficient to enable the reader both to understand the intended areas of application of the languages and to read and construct simple models of each of the three types.

Actualism, ontological commitment, and possible world semantics

Actualism is the doctrine that the only things there are, that have being in any sense, are the things that actually exist. In particular, actualism eschews possibilism, the doctrine that there are merely possible objects. It is widely held that one cannot both be an actualist and at the same time take possible world semantics seriously — that is, take it as the basis for a genuine theory of truth for modal languages, or look to it for insight into the modal structure of reality. For possible world semantics, it is supposed, commits one to possibilism. In this paper I take issue with this view. To the contrary, I argue that one can take possible world semantics seriously and yet remain in full compliance with actualist scruples.

The basic notion of justification

ConclusionOur tasks are then complete. We offered, in J7, a defensible claim that there is a relation of necessity and sufficiency between doxastic and propositional justification. We claimed as well that propositional justification is the basic kind of justification. In order to defend this claim, several tasks were undertaken. First, a preliminary investigation showed that there are at most three irreducible kinds of justification. In order to show that there is only one kind, we first showed how personal justification is equivalent to doxastic justification. We then showed that, whereas doxastic justification can be defined in terms of propositional justification, propositional justification cannot be defined in terms of that kind of doxastic justification predicable of tokens of beliefs. We conclude that propositional justification is the basic kinds of justification.These results have implications both for the substance of epistemology and for the methodology employed in constructing an epistemological theory. First, no version of reliabilism can be defended by claiming that there are fundamentally distinct and irreducible notions of justification. Further, the procedure adopted by those versions of reliabilism which count as instances of Aristotelian epistemology cannot be correct. Such theories begin by discussing our intellectual powers, faculties, virtues, or cognitive processes and then define a primitive notion of justification in terms of the doxastic products of such powers, faculties, virtues, or processes. This approach cannot succeed, for, as we have seen, no such theory can given an adequate explanation of the connection between doxastic and propositional justification. For these theories to succeed, one of three alternatives must be available. The first is that propositional justification is explicable in terms of doxastic justification; as we have seen, that claim is false. The second and third alternatives are that Aristotelians either might claim irreducibility between propositional and doxastic justification, or the might hold that, for some reason or other, there is no such thing as propositional justification. Both of these alternatives are unattractive because of the plausibility of J7. If it is adequate, then doxastic justification is explicable in terms of propositional justification. Further, if J7 is adequate, claiming that there is no such thing as propositional justification puts the notion of doxastic justification in jeopardy as well, for doxastic justification is definable in terms of propositional justification. In sum: present reliabilist theories which hold that justification is the result of the proper employment of our cognitive equipment, and which are thereby committed to constructing a theory of justification with doxastic justification as the basic notion of justification, are incompatible with the fact that propositional justification is the basic kind of justification.

An integrated process model driven knowledge based system for remote customer support

This paper describes a demonstrator in the Globeman 21 project of the international IMS initiative to investigate the use of information technology tools and methods such as the World Wide Web to support remote customers. The focus of the demonstrator is an Australian company manufacturing CNC plate cutting machines. Because the company has customers all over the world, it needs to provide effective and responsive remote support to customers in the use, maintenance and troubleshooting of their equipment. The research in the project starts with an understanding of the underlying logic of human expert reasoning and hence provides a process model which directs the customer through the necessary dialog procedures. A knowledge repository is created to capture the knowledge of company domain experts as well as field information available from experienced users. A set of software tools has been created in the project which integrates the process model and the knowledge base and allows changes to be made easily by the company.

A formal foundation for process modeling

Process modeling is ubiquitous in business and industry. While agreat deal of effort has been devoted to the formal andphilosophical investigation of processes, surprisingly littleresearch connects this work to real world process modeling. Thepurpose of this paper is to begin making such a connection. To doso, we first develop a simple mathematical model of activities andtheir instances based upon the model theory for the NIST ProcessSpecification Language (PSL), a simple language for describingthese entities, and a semantics for the latter in terms of theformer, and a set of axioms for the semantics based upon the NISTProcess Specification Language (PSL). On the basis of thisfoundation, we then develop a general notion of a process model,and an account of what it is for such a model to be realized by acollection of events.

Toward a method for acquiring CIM ontologies

Abstract An important requirement for world-class CIM systems is the ability to capture knowledge from multiple disciplines and store it in a form that facilitates re-use, sharing, and extendibility. Taxonomies and glossaries, in and of themselves, will not fully address this requirement, and will need to be supplemented so as to circumscribe the meanings and logical properties of the terms as precisely as possible. We thus perceive the need for ontologies rather than mere taxonomies. An ontology is a description of the kinds of things, both physical and conceptual, that make up a given domain and the relationships among them as represented by the terminology in that domain. This paper describes a scientific method for acquiring, structuring and maintaining CIM ontologies. An ontology capture method is essential to developing practical CIM ontologies because it facilitates the direct capture of CIM knowledge by practitioners within the manufacturing domain. The proposed ontology capture method includes: (...

Knowledge representation, the World Wide Web, and the evolution of logic

It is almost universally acknowledged that first-order logic (FOL), with its clean, well-understood syntax and semantics, allows for the clear expression of philosophical arguments and ideas. Indeed, an argument or philosophical theory rendered in FOL is perhaps the cleanest example there is of “representing philosophy”. A number of prominent syntactic and semantic properties of FOL reflect metaphysical presuppositions that stem from its Fregean origins, particularly the idea of an inviolable divide between concept and object. These presuppositions, taken at face value, reflect a significant metaphysical viewpoint, one that can in fact hinder or prejudice the representation of philosophical ideas and arguments. Philosophers have of course noticed this and have, accordingly, sought to alter or extend traditional FOL in novel ways to reflect a more flexible and egalitarian metaphysical standpoint. The purpose of this paper, however, is to document and discuss how similar “adaptations” to FOL—culminating in a standardized framework known as Common Logic—have evolved out of the more practical and applied encounter of FOL with the problem of representing, sharing, and reasoning upon information on World Wide Web.

Situations and Processes

Typical methods for representing business engineering and manufacturing processes represent process information by means of rather restricted often graphical languages These languages are often fine as far as they go, but for many purposes—information sharing, in particular—much more precise, detailed representations of enterprise processes are required In this paper, we develop an approach to the rigor ous representation of process information based on situation theory We begin with an informal account of the semantic categories of the ap proach including situations, infons types activities, and processes, as well as the central relations that can hold between them A frame work—known as ST based roughly on the Knowledge Interchange Format (KIF) is introduced for expressing information in these terms The use of ST is then illustrated in detail by means of a series of examples Finally the formal semantics for ST is sketched and the language and basic logic of ST is formally defined

The Fundamental Theorem of World Theory

The fundamental principle of the theory of possible worlds is that a proposition p is possible if and only if there is a possible world at which p is true. In this paper we present a valid derivation of this principle from a more general theory in which possible worlds are defined rather than taken as primitive. The general theory uses a primitive modality and axiomatizes abstract objects, properties, and propositions. We then show that this general theory has very small models and hence that its ontological commitments—and, therefore, those of the fundamental principle of world theory—are minimal.