ABSTRACT
Tabu search (TS) is based on the premise that problem-solving, to qualify as intelligent, must incorporate adaptive memory and responsive exploration. The adaptive memory feature of TS allows the implementation of procedures that are capable of searching the solution space economically and effectively. The use of recency and frequency memory in tabu search generally fulfills the function of preventing searching processes from cycling, that is, from endlessly executing the same sequence of moves. More broadly, however, the various manifestations of these types of memory are designed to impart additional robustness or vigor to the search. Diversification is automatically created in TS (to some extent) by short-term memory functions but is particularly reinforced by certain forms of longer term memory. TS diversification strategies are often based on modifying choice rules to bring attributes into the solutions that are infrequently used. There are many forms in which a simple tabu search implementation can be improved by adding long-term elements.
