We introduce a compressed suffix array representation that, on a text T of length n over an alphabet of size σ, can be built in O(n) deterministic time, within O(n log σ) bits of working space, and counts the number of occurrences of any pattern P in T in time O(|P |+log logw σ) on a RAM machine of w = Ω(logn)-bit words. This new index outperforms all the other compressed indexes that can be bu...

Two of the most commonly used models in computational learning theory are the distribution-free model in which examples are chosen from a fixed but arbitrary distribution, and the absolute mistake-bound model in which examples are presented in an arbitrary order. Over the Boolean domain {0, 1}, it is known that if the learner is allowed unlimited computational resources then any concept class l...

The problem of finding dominators in a flowgraph arises in many kinds of global code optimization and other settings. In 1979 Lengauer and Tarjan gave an almost-linear-time algorithm to find dominators. In 1985 Harel claimed a lineartime algorithm, but this algorithm was incomplete; Alstrup et al. [1999] gave a complete and “simpler” linear-time algorithm on a random-access machine. In 1998, Bu...

The on-chip memory performance of embedded systems directly affects the system designers’ decision about how to allocate expensive silicon area. We investigate a novel random access memory (RAM) architecture for embedded systems that allows both random-access and sequential-access for reads and writes. To realize sequential accesses, small “links” are added to each row in the RAM array to point...

Battery-backed-up DRAM memories can be configured today to be almost as reliable as disk. This paper argues that it is cost-effective to employ Safe RAM in computer systems which support reliable updates. Safe RAM allows systems that support reliable updates, such as database and transaction processing systems, to perform more efficiently. We show how a response time improvement can always be r...

We investigated the performance of spin transfer torque random access memory (STTRAM) cell with cross shaped Heusler compound based free layer using micromagnetic simulations. We designed the free layer using Cobalt based Heusler compounds. Here in this paper, simulation results predict that switching time from one state to other state is reduced. Also it is examined that critical switching cur...

We show in this paper that the BGS model of abstract state machines can be simulated by random access machines with at most a polynomial time overhead. This result is already stated in [BGS99] with a very brief proof sketch. The present paper gives a detailed proof of the result. We represent hereditarily finite sets, which are the typical BGS ASM objects, by membership graphs of the transitive...

Thorup recently showed that single-source shortest-paths problems in undirected networks with n vertices, m edges, and edge weights drawn from {0, . . . , 2 − 1} can be solved in O(n+m) time and space on a unit-cost random-access machine with a word length of w bits. His algorithm works by traversing a so-called component tree. Two new related results are provided here. First, and most importan...

The OR-NOT operation x _ y between two binary vectors x and y of the same length is viewed as an operation between the new and old content of a random-access memory used to increase the speed of the access to the memory. Coding procedures that allow us to recover x based on x_y are developed and connections of this model of the memory with the model of write-unidirectional memory are established.

There are many variations of the basic parallel random access machine (PRAM), which includes an arbitrary number of processors sharing an arbitrary amount of random access memory. An exclusive-read, exclusive-write PRAM (EREW PRAM) does not allow any concurrent memory accesses (so all concurrent memory accesses must be explicitly serialized in the program). An EREW PRAM is useful because any al...