Application Of Logic Programming Research Articles

Application of Logic Programming in Linear System Identification

An experimental CAD system is built, demonstrating the utility of coupling numerical and logic programming in solving model identification problems. The feasibility study is performed on a software package for model based signal processing (SIG) coupled together with a standard Edinburgh PROLOG interpreter. The rule-based advisor written in PROLOG helps the identification algorithm written in the SIG command language to choose the structure of an ARMAX model that fits best a given time series sequence. Simulation experiments confirm the utility of coupling the numerical and logic programming packages for this purpose.

Choosing directions for rules

In ‘expert systems’ and other applications of logic programming, the issue arises of whether to use rules for forward or backward inference, i.e. whether deduction should be driven by the facts available to the program or the questions that are put to it. Often some mixture of the two is cheaper than using either mode exclusively. We show that, under two restrictive assumptions, optimal choices of directions for the rules can be made in time polynomial in the number of rules in the system. If we abandon one of these restrictions, the optimal choice is NP-complete. Search methods are presented which allow graceful degradation from polynomial time to exponential time. The cost estimates on which the optimisation is based are also discussed. The methods used to estimate costs fail when recursion is present in the rules, thus limiting the set of logic programs to which this optimisation can be applied.

The application of logic programming to the generation of plans for robots

SUMMARYThe previous paper by the same authors (Robotica 2, Part 2, pp. 93–103 1984) was concerned with the application of logic programming to the generation of paths for robots. This paper is dealing with the PIGS system for robot problem-solving in generating plans for robots. The system avoids the overhead of generating a new set of facts for each state considered. A computer-type control is adopted not only to generate a simple sequence of actions to be performed by the robot, but also to enable the robot to follow an accurately defined path. A suitable plan of action of a robot problem-solving system is generated. The system is written in the PROLOG language and acts as a robot plan generator that is integrated with a path finding procedure in order to avoid collisions whilst plans are being implemented.

The application of logic programming to the generation of paths for robots

SUMMARYThis paper outlines a heuristic approach for the development of a control strategy for finding a safe path for a polyhedral object moving amongst known polyhedral objects. This is achieved by the algorithm A* for finding a minimum cost path in a graph; the algorithm is implemented on a computer under the UNIX operating system, using the NU7 version of PROLOG.