Margaret Mary West

Acquiring planning domain models using LOCM

The problem of formulating knowledge bases containing action schema is a central concern in knowledge engineering for AI Planning. This paper describes LOCM, a system which carries out the automated generation of a planning domain model from example training plans. The novelty of LOCM is that it can induce action schema without being provided with any information about predicates or initial, goal or intermediate state descriptions for the example action sequences. Each plan is assumed to be a sound sequence of actions; each action in a plan is stated as a name and a list of objects that the action refers to. LOCM exploits assumptions about the kinds of domain model it has to generate, rather than handcrafted clues or planner-oriented knowledge. It assumes that actions change the state of objects, and require objects to be in a certain state before they can be executed. In this paper we describe the implemented LOCM algorithm, the assumptions that it is based on, and an evaluation using plans generated through goal directed solutions, through random walk, and through logging human generated plans for the game of Freecell. We analyse the performance of LOCM by its application to the induction of domain models from five domains.

THE APPLICATION OF MACHINE LEARNING TOOLS TO THE VALIDATION OF AN AIR TRAFFIC CONTROL DOMAIN THEORY

In this paper we describe a project (IMPRESS) in which machine learning (ML) tools were created and utilised for the validation of an Air Traffic Control domain theory written in first order logic. During the project, novel techniques were devised for the automated revision of general clause form theories using training examples. These techniques were combined in an algorithm which focused in on the parts of a theory which involve ordinal sorts, and applied geometrical revision operators to repair faulty component parts. While we illustrate the feasibility of applying ML to this area, we conclude that to be effective it must be focused to the application at hand, and used in mixed-initiative mode within a tools environment. The method is illustrated with experimental results obtained during the project.

Action Knowledge Acquisition with Opmaker2

AI planning engines require detailed specifications of dynamic knowledge of the domain in which they are to operate, before they can function. Further, they require domain-specific heuristics before they can function efficiently. The problem of formulating domain models containing dynamic knowledge regarding actions is a barrier to the widespread uptake of AI planning, because of the difficulty in acquiring and maintaining them. Here we postulate a method which inputs a partial domain model (one without knowledge of domain actions) and training solution sequences to planning tasks, and outputs the full domain model, including heuristics that can be used to make plan generation more efficient.

The Automated Refinement of a Requirements Domain Theory

The specification and management of requirements is widely considered to be one of the most important yet most problematic activities in software engineering. In some applications, such as in safety critical areas or knowledge-based systems, the construction of a requirements domain theory is regarded as an important part of this activity. Building and maintaining such a domain theory, however, requires a large investment and a range of powerful validation and maintenance tools. The area of theory refinement is concerned with the use of training data to automatically change an existing theory so that it better fits the data. Theory refinement techniques, however, have not been extensively used in applications because of the problems in scaling up their underlying algorithms. In our work we have applied theory refinement to assist in the problem of validation and maintenance of a requirements theory concerning separation standards in the North East Atlantic. In this paper we describe an implemented refinement algorithm, which processes a logic program automatically generated from the theory. We overcame the size and expressiveness problems typically encountered when applying theory refinement to a logic program of this kind by designing focused, composite refinement operators within the algorithm. These operators modify the auto-generated logic program by generalising or specialising clauses containing ordinal relations—that is relations which operate on totally ordered data.

Towards the automated debugging and maintenance of logic-based requirements models

We describe a tools environment which automates the validation and maintenance of a requirements model written in many-sorted first order logic. We focus on a translator that produces an executable form of the model; blame assignment functions, which input batches of mis-classified tests (i.e. training examples) and output likely faulty parts of the model; and a theory reviser; which inputs the faulty parts and examples and outputs suggested revisions to the model. In particular we concentrate on the problems encountered when applying these tools to a real application: a requirements model containing air traffic control separation standards, operating methods and airspace information.

The use of a logic programming language in the animation of Z specifications

Animation of a formal specification involves its execution and this paper is concerned with Z specifications and their correct animation. Since Z is based on typed set theory the logic programming language Godel [2] was chosen as the execution language. Abstract Approximation was suggested in [1] to provide a formal framework and some proof rules for the correct animation of Z. We describe here how the correctness criteria are applied to our method of structure simulation [3].

The application of a machine learning tool to the validation of an air traffic control domain theory

In this paper we describe a project (IMPRESS) which utilised a machine learning tool for the validation of an air traffic control domain theory. During the project, novel techniques were devised for the automated revision of general clause form theories using training examples. This technique involves focusing in on the parts of a theory which involve ordinal sorts, and applying geometrical revision operators to repair faulty component parts. The method is illustrated with experimental results obtained during the project.