4 research outputs found
Experience with mural in formalising Dust-Expert
The mural system was an outcome of a significant effort to develop a support tool for the effective use of a full formal methods development cycle. Experience with it, however, has been limited to a small number of illustrative examples that have been carried out by those closely associated with its development and implementation. This paper aims to remedy this situation by describing the experience of using mural for specifying Dust-Expert, an expert system for the relief venting of dust explosions in chemical processes. The paper begins by summarising the main requirements for Dust-Expert, and then gives a ¯avour of the VDM speci®cation that was formalised using mural.
The experience of using mural is described with respect to users' expectations that a formal methods tool should: (i) spot any inconsistencies; (ii) help manage and organise the specifications and allow one to easily add, access, update and delete specifications; (iii) help manage and carry out the refinement process; (iv) help manage and organise theories; (v) help manage and carry out proofs. The paper concludes by highlighting the strengths and weaknesses of mural that could be of interest to those developing the next generation of formal methods development tools
AI and OR in management of operations: history and trends
The last decade has seen a considerable growth in the use of Artificial Intelligence (AI) for operations management with the aim of finding solutions to problems that are increasing in complexity and scale. This paper begins by setting the context for the survey through a historical perspective of OR and AI. An extensive survey of applications of AI techniques for operations management, covering a total of over 1200 papers published from 1995 to 2004 is then presented. The survey utilizes Elsevier's ScienceDirect database as a source. Hence, the survey may not cover all the relevant journals but includes a sufficiently wide range of publications to make it representative of the research in the field. The papers are categorized into four areas of operations management: (a) design, (b) scheduling, (c) process planning and control and (d) quality, maintenance and fault diagnosis. Each of the four areas is categorized in terms of the AI techniques used: genetic algorithms, case-based reasoning, knowledge-based systems, fuzzy logic and hybrid techniques. The trends over the last decade are identified, discussed with respect to expected trends and directions for future work suggested
On the mechanisation of the logic of partial functions
PhD ThesisIt is well known that partial functions arise frequently in formal reasoning
about programs. A partial function may not yield a value for every member
of its domain. Terms that apply partial functions thus may not denote, and
coping with such terms is problematic in two-valued classical logic. A question
is raised: how can reasoning about logical formulae that can contain references
to terms that may fail to denote (partial terms) be conducted formally? Over
the years a number of approaches to coping with partial terms have been
documented. Some of these approaches attempt to stay within the realm
of two-valued classical logic, while others are based on non-classical logics.
However, as yet there is no consensus on which approach is the best one to
use. A comparison of numerous approaches to coping with partial terms is
presented based upon formal semantic definitions.
One approach to coping with partial terms that has received attention over
the years is the Logic of Partial Functions (LPF), which is the logic underlying
the Vienna Development Method. LPF is a non-classical three-valued logic
designed to cope with partial terms, where both terms and propositions may
fail to denote. As opposed to using concrete undfined values, undefinedness
is treated as a \gap", that is, the absence of a defined value. LPF is based
upon Strong Kleene logic, where the interpretations of the logical operators
are extended to cope with truth value \gaps".
Over the years a large body of research and engineering has gone into the
development of proof based tool support for two-valued classical logic. This
has created a major obstacle that affects the adoption of LPF, since such proof
support cannot be carried over directly to LPF. Presently, there is a lack of
direct proof support for LPF.
An aim of this work is to investigate the applicability of mechanised (automated)
proof support for reasoning about logical formulae that can contain
references to partial terms in LPF. The focus of the investigation is on the basic
but fundamental two-valued classical logic proof procedure: resolution and
the associated technique proof by contradiction. Advanced proof techniques
are built on the foundation that is provided by these basic fundamental proof
techniques. Looking at the impact of these basic fundamental proof techniques
in LPF is thus the essential and obvious starting point for investigating proof
support for LPF. The work highlights the issues that arise when applying
these basic techniques in LPF, and investigates the extent of the modifications needed to carry them over to LPF. This work provides the essential foundation
on which to facilitate research into the modification of advanced proof
techniques for LPF.EPSR