Showing papers on "Backtracking published in 1973"

MALB—A Heuristic Technique for Balancing Large Single-Model Assembly Lines

Abstract: This paper is concerned with the development of a heuristic algorithm (MALB) for the general solution of large single-model assembly line balancing problems. It is based on the optimum-seeking backtracking method proposed by Mansoor (1964). Excellent results were obtained from tests taken over a wide range of large ALB problems. Over a third of the tests yielded a 100% line efficiency and the overall computation time was 22 sec on an IBM 7040/7044.

A branch-and-bound approach to the job-shop scheduling problem

Abstract: SUMMARY The shop scheduling problem with which this paper is concerned is to determine a sequence of J jobs on each of the M machines such that the schedule time is minimized. The machine ordering of each job is pre-specified but independent of those of other jobs. A branch-and-bound algorithm, using a powerful bounding procedure, has been developed for obtaining an optimal solution. An illustrative example is solved. Computational experience with this algorithm shows that it is practical in problems of moderate size. However, for larger problems, the algorithm can be applied without backtracking in which an optimal or near-optimal solution may be obtained. The quality of solutions obtained by the branch-and-bound algorithm without backtracking has been investigated. The optimal-producing algorithm is compared favourably with other published methods The number of nodes explored and the computational time are considered as bases for evaluation.

Backtracking in MLISP2: an efficient backtracking method for LISP

Abstract: An efficient backtracking method for LISP, used in the MLISP2 language, is described. The method is optimal in the following senses: (1) Only necessary state information is saved. The backtracking system routines are sufficiently efficient to require less than ten percent of the execution time of typical jobs. (2) Most common operations -- fetching/storing the value of a variable or the property of an atom, function entry/exit -- take no longer with backtracking than without it. This is achieved by not changing the way values are stored. (3) If backtracking is not used, an insignificant overhead is involved in maintaining the backtracking capability. The MLISP2 algorithm and philosophy are briefly contrasted with those of several existing backtracking systems, with historical comments on the development of the theory of backtracking.