Linda Morales

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Given the growing number of group applications in many existing and evolving domains recent attention has been focused on secure multicasting over the Internet. When such systems are required to manage large groups that undergo frequent fluctuations in group membership, the need for efficient encryption key management becomes critical. This paper presents a(More)
There are numerous applications that require secure group communication. Much recent attention has been focused on secure multicasting over the Internet. When such systems are required to manage large groups which undergo frequent fluctuations in group membership, the need for efficient encryption key management becomes critical. This paper presents a(More)
Secure multicast has a variety of applications in ecommerce, e-banking, command and control, video-ondemand, and other internet-based services. In this paper, we present algorithms to improve on the number of rekeying messages (overhead) needed to add and delete sets of users to a secure multicast group. We present upper and lower bounds on the number of(More)
Applications in information security, data mining, e-commerce, information retrieval and network management require the analysis of large graphs in order to discover homogeneous groupings of rows and columns, called cross associations. We show that finding an optimal cross association is NP-complete. Furthermore, we give a heuristic algorithm with an O(n)(More)
A technique for clustering data by common attribute values involves grouping rows and columns of a binary matrix to make the minimum number of submatrices all 1’s. As binary matrices can be viewed as adjacency matrices of bipartite graphs, the problem is equivalent to partitioning a bipartite graph into the smallest number of complete bipartite sub-graphs(More)
We give an approximation algorithm for the block sorting problem with an approximation ratio of 2 and run time O(n). The approximation algorithm is based on the related concept of block deletion. We show that finding an optimum block deletion sequence can be done in O(n) time, while block sorting is known to be NP-hard. Block sorting has importance in(More)
The "traditional" use of the Positive Deviance approach to behavior change involves studying children who thrive despite adversity, identifying uncommon model behaviors among Positive Deviant families, and then designing and implementing an intervention to replicate these behaviors among mothers of malnourished children. This article presents the results of(More)
Low dilation embeddings are used to compare similarities between star and pancake networks. The pancake network of dimension n, Pn, has n! nodes, one for each permutation, and an undirected edge between permutations (nodes) when some prefix reversal transforms one permutation into the other. The star network of dimension n, Sn, has n! nodes, one for each(More)