Iterative methods such as Lanczos and Jacobi-Davidson are typically used to compute a small number of eigenvalues and eigenvectors of a sparse matrix. However, these methods are not effective in certain large-scale applications, for example, “global tight binding molecular dynamics.” Such applications require all the eigenvectors of a large sparse matrix; the eigenvectors can be computed a few ...

Proofs of space (PoS) were suggested as more ecological and economical alternative to proofs of work, which are currently used in blockchain designs like Bitcoin. The existing PoS are based on rather sophisticated graph pebbling lower bounds. Much simpler and in several aspects more efficient schemes based on inverting random functions have been suggested, but they don’t give meaningful securit...

Increased application of structured pattern mining requires a perfect understanding of the problem and a clear identification of the advantages and disadvantages of existing algorithms. Among those algorithms, pattern-growth methods have been shown to have the best performance when applied to sequential pattern mining. However, their advantages over apriori-based methods are not well explained ...

In spite of the mature cell structure, the memory controller architecture of Multi-level cell (MLC) NAND Flash memories is evolving fast in an attempt to improve the uncorrected/miscorrected bit error rate (UBER) and to provide a more flexible usage model where the performance-reliability trade-off point can be adjusted at runtime. However, optimization techniques in the memory controller archi...

We study space complexity and time-space trade-offs with a focus not on peak memory usage but on overall memory consumption throughout the computation. Such a cumulative space measure was introduced for the computational model of parallel black pebbling by [Alwen and Serbinenko ’15] as a tool for obtaining results in cryptography. We consider instead the nondeterministic black-white pebble game...

The performance of the Time Warp mechanism is experimentally evaluated when only a limited amount of memory is available to the parallel computation. An implementation of the cancelback protocol is used for memory management on a shared memory architecture, viz., KSR to evaluate the performance vs. memory tradeoff. The implementation of the cancelback protocol supports canceling back more than ...

We present Lyra2, a password hashing scheme (PHS) based on cryptographic sponges. Lyra2 was designed to be strictly sequential (i.e., not easily parallelizable), providing strong security even against attackers that uses multiple processing cores (e.g., custom hardware or a powerful GPU). At the same time, it is very simple to implement in software and allows legitimate users to fine tune its m...

Having to cope with memory limitations is an ubiquitous issue in heuristic search. We present theoretical and practical results on new variants for exploring state-space with respect to memory limitations. We establish O(log n) minimum-space algorithms that omit both the open and the closed list to determine the shortest path between every two nodes and study the gap in between full memorizatio...

The time memory trade-off (TMTO) algorithm, first introduced by Hellman, is a method for quickly inverting a one-way function, using pre-computed tables. The distinguished point method (DP) is a technique that reduces the number of table lookups performed by Hellman’s algorithm. In this paper we propose a new variant of the DP technique, named variable DP (VDP), having properties very different...