Issue No. 03 - March (1984 vol. 6)
Y. T. Chiang , School of Electrical Engineering, Purdue University, West Lafayette, IN 47907; Department of Electrical and Computer Engineering, Washington State University, Pullman, WA 99163.
K. S. Fu , School of Electrical Engineering, Purdue University, West Lafayette, IN 47907.
Earley's algorithm has been commonly used for the parsing of general context-free languages and the error-correcting parsing in syntactic pattern recognition. The time complexity for parsing is 0(n3). This paper presents a parallel Earley's recognition algorithm in terms of an ``X*'' operator. By restricting the input context-free grammar to be ¿-free, the parallel algorithm can be executed on a triangular-shape VLSI array. This array system has an efficient way of moving data to the right place at the right time. Simulation results show that this system can recognize a string with length n in 2n + 1 system time. We also present a parallel parse-extraction algorithm, a complete parsing algorithm, and an error-correcting recognition algorithm. The parallel complete parsing algorithm has been simulated on a processor array which is similar to the triangular VLSI array. For an input string of length n the processor array will give the correct right-parse at system time 2n + 1 if the string is accepted. The error-correcting recognition algorithm has also been simulated on a triangular VLSI array. This array recognizes an erroneous string of length n in time 2n + 1 and gives the correct error count. These parallel algorithms are especially useful for syntactic pattern recognition.
Y. T. Chiang and K. S. Fu, "Parallel Parsing Algorithms and VLSI Implementations for Syntactic Pattern Recognition," in IEEE Transactions on Pattern Analysis & Machine Intelligence, vol. 6, no. , pp. 302-314, 1984.