N. R. Achuthan

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Frequent pattern mining discovers patterns in transaction databases based only on the relative frequency of occurrence of items without considering their utility. For many real world applications, however, utility of itemsets based on cost, profit or revenue is of importance. The utility mining problem is to find itemsets that have higher utility than a(More)
Let G be a simple undirected graph with non-negative edge weights. In this paper we consider the following combinatorial optimization problem : Find, in G, a minimum weight spanning tree having diameter at most D. This problem is trivial for D :S 3 and NP-complete for D :: 4. In this paper we develop and implement a number of Branch and Bound algorithms for(More)
Mining High Utility Itemsets from a transaction database is to find itemsests that have utility above a user-specified threshold. This problem is an extension of Frequent Itemset Mining, which discovers itemsets that occur frequently (i.e. with occurrence count larger than a user given value). The problem of finding High Utility Itemsets is challenging,(More)
High utility itemsets mining extends frequent pattern mining to discover itemsets in a transaction database with utility values above a given threshold. However, mining high utility itemsets presents a greater challenge than frequent itemset mining, since high utility itemsets lack the anti-monotone property of frequent itemsets. Transaction Weighted(More)
MINIMUM WEIGHT SPANNING TREES WITH BOUNDED DIAMETER N.R. Achuthan and L. Caccetta School of Mathematics and Statistics Curtin University of Technology GPO Box U1987 Perth, 6001 Western Australia. Let G be a simple graph with non-negative edge weights. Determining a minimum weight spanning tree is a fundamental problem that arises in network design and as a(More)
Several long-standing problems in software engineering are concerned with inadequate requirements elicitation, analysis, specification, validation, and management. This deficit is a major cause of project failure and as such several techniques and frameworks have been developed to assist developers in handling requirements. Methods for handling functional(More)
Let !:ten) denote the class of simple graphs of order n. For G € !:t(n) , G denotes the complement of G. Given a graph theoretic parameter f, the Nordhaus-Gaddum Problem is to find lower and upper bounds for: and f(G) + f(G) , f(G) f(G) , over the class !:ten). In this paper we consider a variation of this problem by restricting our attention to the(More)
A graph is (m,k)-colourable if its vertices can be coloured with m colours such that the maximum degree of the subgraph induced on vertices receiving the same colour is at most k. The k-defedive chromatic number Xk(G) of a graph G is the least positive integer m for which G is (m,k)-colourable. In this paper we obtain a sharp upper bound for XI (G) + X/G)(More)
A graph G is (m, k)-colourable if its vertices can be coloured with m colours such that the maximum degree of the subgraph induced on vertices receiving the same colour is at most k. The k-defective chromatic number χk(G) is the least positive integer m for which G is (m, k)-colourable. In 1988 Maddox proved that if either G or Ḡ is triangle-free graph of(More)