April 1978 - Vol. 21 No. 4
Features
Orderly enumeration of nonsingular binary matrices applied to text encryption
Nonsingular binary matrices of order N, i.e., nonsingular over the field {0, 1}, and an initial segment of the natural numbers are placed in one-to-one correspondence.…
A technique for isolating differences between files
A simple algorithm is described for isolating the differences between two files. One application is the comparing of two versions of a source program or other file in…
Optimal conversion of extended-entry decision tables with general cost criteria
A general dynamic programming algorithm for converting limited, extended, or mixed entry decision tables to optimal decision trees is presented which can take into…
List processing in real time on a serial computer
A real-time list processing system is one in which the time required by the elementary list operations (e.g. CONS, CAR, CDR, RPLACA, RPLACD, EQ, and ATOM in LISP) is…
Secure communications over insecure channels
According to traditional conceptions of cryptographic security, it is necessary to transmit a key, by secret means, before encrypted massages can be sent securely. This…
Assembling code for machines with span-dependent instructions
Many modern computers contain instructions whose lengths depend on the distance from a given instance of such an instruction to the operand of that instruction. This…
A data structure for manipulating priority queues
A data structure is described which can be used for representing a collection of priority queues. The primitive operations are insertion, deletion, union, update, and…
Economical encoding of commas between strings
A method for insertion of delimiters between strings without using new symbols is presented. As the lengths of the strings increase, the extra cost, in terms of…
Generating beta variates with nonintegral shape parameters
A new rejection method is described for generating beta variates. The method is compared with previously published methods both theoretically and through computer…