Early artificial intelligence programming languages that incorporated search and backtracking facilities did not limit backtracking to previous computations when a portion of a search failed [1]. This had two unpleasant consequences: (1) the amount of data that had to be retained to allow backtracking limited the problems that could be handled, and (2) unexpected failure could cause backtrackin...

The only technique available for solving many important problems is searching. Since searching can be extremely costly, it is important to identify features that improve the efficiency of aearch algorithms. We compute the efficiency of simple backtracking, of an algorithm similar to backtracking except that it notices when the predicate is empty instead of noticing when it is unsatlsfiable (the...

Multiagent solutions to the distributed constraint satisfaction problem (DCSP) require new types of techniques which accommodate the local autonomy of agents and the difficulties of computing in a network environment. Recently a technique called asynchronous backtracking has been developed to solve the DCSP. The algorithm works by sending nogood messages among agents to effect intelligent backt...

We present a selective backtracking method for Horn clause programs, as applied to Prolog (2)[8)(11)[12], a programming language based on first-order predicate calculus (3)(4)~ developed at the university of Marseille (18]. This method is based on the general method expounded in (7] for backtracking intelligently in AND/OR trees. It consists, essentially, in avoiding backtracking to any goal wh...

Frequent codirectional collisions between the replisome and RNA polymerase (RNAP) are inevitable because the rate of replication is much faster than that of transcription. Here we show that, in E. coli, the outcome of such collisions depends on the productive state of transcription elongation complexes (ECs). Codirectional collisions with backtracked (arrested) ECs lead to DNA double-strand bre...

An incremental pseudorandom bit generator (iPRBG) is backtracking resistant if a state compromise does not allow the attacker a non-negligible advantage at distinguishing previouslygenerated bits from uniformly distributed random bits. Backtracking resistance can provide increased security in cryptographic protocols with long-term secrecy requirements. While a necessary condition for an iPRBG t...

Scheduling and timetabling problems are multi-constrained constraint satisfaction problems that have huge search space. These problems are NP hard. This paper investigates the use of backtracking approaches to laboratory personnel scheduling problem in which the objective is to assign tasks to employees. The main objective of this work is to search for better solutions than those obtained by au...