Ali Vakilian

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We develop the first streaming algorithm and the first two-party communication protocol that uses a constant number of passes/rounds and sublinear space/communication for logarithmic approximation to the classic Set Cover problem. Specifically, for n elements andm sets, our algorithm/protocol achieves a space bound of O(m · n log n logm) using O(4)(More)
We consider node-weighted network design problems, in particular the survivable network design problem (SNDP) and its prize-collecting version (PC-SNDP). The input consists of a node-weighted undirected graphG = (V,E) and integral connectivity requirements r(st) for each pair of nodes st. The goal is to find a minimum node-weighted subgraph H of G such(More)
We consider the classic Set Cover problem in the data stream model. For n elements and m sets (m &#8805; n) we give a O(1/&#948;)-pass algorithm with a strongly sub-linear ~O(mn<sup>&#948;</sup>) space and logarithmic approximation factor. This yields a significant improvement over the earlier algorithm of Demaine et al. [10] that uses exponentially larger(More)
We consider node-weighted network design problems, in particular the survivable network design problem (SNDP) and its prize-collecting version (PC-SNDP). The input consists of a node-weighted undirected graph G = (V,E) and integral connectivity requirements r(st) for each pair of nodes st. The goal is to find a minimum node-weighted subgraph H of G such(More)
We consider node-weighted network design in planar and minor-closed families of graphs. In particular we focus on the edge-connectivity survivable network design problem (EC-SNDP). The input consists of a node-weighted undirected graph G = (V,E) and integral connectivity requirements r(uv) for each pair of nodes uv. The goal is to find a minimum(More)
OBJECTIVE To compare heart rate variability (HRV) and QT dispersion in comatose patients with normal brainstem function and with brain death. STUDY DESIGN Cross-sectional comparative study. PLACE AND DURATION OF STUDY The Intensive Care Unit of Ali-Ebn-Abitaleleb Hopital, Rafsanjan Medical University from September 2007 to June 2009. METHODOLOGY(More)
We consider <i>degree bounded</i> network design problems with element and vertex connectivity requirements. In the degree bounded Survivable Network Design (SNDP) problem, the input is an undirected graph <i>G</i> = (<i>V, E</i>) with weights <i>w</i>(<i>e</i>) on the edges and degree bounds <i>b</i>(<i>v</i>) on the vertices, and connectivity requirements(More)
It is well established that extracting and annotating occurrences of entities in a collection of unstructured text documents with their concepts improve the effectiveness of answering queries over the collection. However, it is very resource intensive to create and maintain large annotated collections. Since the available resources of an enterprise are(More)