Search results for "Counting problem"
showing 3 items of 3 documents
On a Conjecture by Christian Choffrut
2017
It is one of the most famous open problems to determine the minimum amount of states required by a deterministic finite automaton to distinguish a pair of strings, which was stated by Christian Choffrut more than thirty years ago. We investigate the same question for different automata models and we obtain new upper and lower bounds for some of them including alternating, ultrametric, quantum, and affine finite automata.
Computing the Probability for Data Loss in Two-Dimensional Parity RAIDs
2017
Parity RAIDs are used to protect storage systems against disk failures. The idea is to add redundancy to the system by storing the parity of subsets of disks on extra parity disks. A simple two-dimensional scheme is the one in which the data disks are arranged in a rectangular grid, and every row and column is extended by one disk which stores the parity of it.In this paper we describe several two-dimensional parity RAIDs and analyse, for each of them, the probability for dataloss given that f random disks fail. This probability can be used to determine the overall probability using the model of Hafner and Rao. We reduce subsets of the forest counting problem to the different cases and show…
Advanced Scatter Search for the Max-Cut Problem
2009
The max-cut problem consists of finding a partition of the nodes of a weighted graph into two subsets such that the sum of the weights on the arcs connecting the two subsets is maximized. This is an NP-hard problem that can also be formulated as an integer quadratic program. Several solution methods have been developed since the 1970s and applied to a variety of fields, particularly in engineering and layout design. We propose a heuristic method based on the scatter-search methodology for finding approximate solutions to this optimization problem. Our solution procedure incorporates some innovative features within the scatter-search framework: (1) the solution of the maximum diversity prob…