Antithymocyte globulin and cyclosporin in children with acquired aplastic anemia (2008)
Chandra, J, Naithani, R, Ravi, R, Singh, V, Narayan, S, Sharma, S, ...
High angle of Attack Forebody Flow Physics and Design Emphasizing Directional Stability (2008)
A framework for understanding the fundamental physics of flowfields over forebody type shapes at low speed, high angle of attack conditions with special emphasis on sideslip has been established....
High angle of Attack Forebody Flow Physics and Design Emphasizing Directional Stability (2008)
A framework for understanding the fundamental physics of flowfields over forebody type shapes at low speed, high angle of attack conditions with special emphasis on sideslip has been established....
Direct maximum parsimony phylogeny reconstruction from genotype data (2007)
Sridhar, Srinath, Lam, Fumei, Blelloch, Guy E, Ravi, R, Schwartz, Russell
Abstract Background Maximum parsimony phylogenetic tree reconstruction from genetic variation data is a fundamental problem in computational genetics with many practical applications in population...
Ravi, R, Prasad, YVRK, Sarma, VVS
Materials workability is one of the important aspects for any process design to achieve quality products. Identifying optimum process parameters like temperature, strain rate, and strain are normally...
Dial a Ride from k-forest (2007)
Gupta, Anupam, Hajiaghayi, MohammadTaghi, Nagarajan, Viswanath, Ravi, R.
The k-forest problem is a common generalization of both the k-MST and the dense-$k$-subgraph problems. Formally, given a metric space on $n$ vertices $V$, with $m$ demand pairs $\subseteq V \times V$...
Olsen, D.M., Rodríguez, J.A., Vranic, M., Ramaiah, V., Ravi, R., Diethrich, E., ...
Introducción. Los procedimientos endovasculares en los que se cateteriza la arteria femoral pueden complicarse con la formación de pseudoaneurismas. Recientemente se ha utilizado una técnica menos...
Ravi, R, Prasad, YVRK, Sarma, VVS
Materials workability is one of the important aspects for any process design to achieve quality products. Identifying optimum process parameters like temperature, strain rate, and strain are normally...
Artificial neural network model for predicting stable and unstable regions in Cu-Zn alloys (2006)
Ravi, R, Prasad, YVRK, Sarma, VVS, Raidu, RS
Processing maps are developed using the Dynamic Materials Model (DMM) and instability criterion, which help in choosing optimum process parameters for hot-working of materials. Certain high-level...
Artificial neural network model for predicting stable and unstable regions in Cu-Zn alloys (2006)
Ravi, R, Prasad, YVRK, Sarma, VVS, Raidu, RS
Processing maps are developed using the Dynamic Materials Model (DMM) and instability criterion, which help in choosing optimum process parameters for hot-working of materials. Certain high-level...
Hedging Uncertainty: Approximation Algorithms for Stochastic Optimization Problems (2005)
We study two-stage, finite-scenario stochastic versions of several combinatorial optimization problems, and provide nearly tight approximation algorithms for them. Our problems range from the...
Ravi, R, Prasad, YVRK, Sarma, VVS
Most of the time (and cost) involved in planning hot forging process is related to activities strongly dependent on human expertise, intuition, and creativity, and also to iterative procedure...
Boosted Sampling: Approximation Algorithms for Stochastic (2003)
Anupam Gupta, Martin Pal, R. Ravi, Amitabh Sinha
Several combinatorial optimization problems choose elements to minimize the total cost of constructing a feasible solution that satisfies requirements of clients. For example, in the STEINER TREE...
Covering Graphs using Trees and Stars (2003)
G. Even, N. Garg, J. Konemann, R. Ravi
A tree cover of a graph G is defined as a collection of trees such that their union includes all the vertices of G. The cost of a tree cover is the weight of the maximum weight tree in the tree...
Minmax Payos of a Location Game (2003)
Shuchi Chawla, Uday Rajan, R. Ravi, Amitabh Sinha
We consider a two-player, sequential location game, with n stages. At each stage, players 1 and 2 choose locations from a feasible set in sequence. After all moves are made, consumers each purchase...
Profit Maximizing Mechanisms for the Extended Multicasting Game (2003)
Shuchi Chawla, David Kitchin, Uday Rajan, R. Ravi, Amitabh Sinha
We consider the design of multicast networks when both edges and nodes are selfish agents. Our objective is a budget-balanced, strategy-proof mechanism which selects the set of clients to receive...
Bruce M. Maggs Gary L. Miller Ojas Parekh R. Ravi Shan Leung Maverick Woo (2003)
Bruce M. Maggs, Gary L. Miller, Ojas Parekh, R. Ravi, Shan Leung, Maverick Woo
In this paper we show how to find a support-tree preconditioner for any Laplacian matrix A, i.e., any matrix that can be viewed as the weighted adjacency matrix of an undirected graph G with...
Ravi, R, Prasad, YVRK, Sarma, VVS
Most of the time (and cost) involved in planning hot forging process is related to activities strongly dependent on human expertise, intuition, and creativity, and also to iterative procedure...
Naveen Garg, Rohit Khandekar, Goran Konjevod, R. Ravi, F. S. Salman, Amitabh Sinha
We study two versions of the single sink buy-at-bulk network design problem. We are given a network and a single sink, and several sources which demand a certain amount of ow to be routed to the...
Design and evaluation of propranolol hydrochloride buccal films (2002)
Raghuraman, S, Velrajan, G, Ravi, R, Jeyabalan, B, Johnson, D, Sankar, V
A polylogarithmic approximation algorithm for the group Steiner tree problem (2001)
Naveen Garg, Goran Konjevod, R. Ravi
The group Steiner tree problem is a generalization of the Steiner tree problem where we ae given several subsets (groups) of vertices in a weighted graph, and the goal is to find a minimum-weight...
On Approximating Planar Metrics by Tree Metrics (2001)
Goran Konjevod, R. Ravi, F. Sibel Salmani
We connect the results of Bartal [4] on probabilistic approximation of metric spaces by tree metrics, and Klein, Plotkin and Rao [11] on decompositions of graphs without small Ks,s minors (such as...
Semi-Definite Relaxations for Minimum Bandwidth and other Vertex-Ordering problems.* (2001)
Avrim Blum, Goran Konjevod, R. Ravi, Santosh Vempala
We present simple semi-definite programming relaxations for the NP-hard minimum bandwidth and minimum length linear ordering problems. We then show how these relaxations can be rounded in a natural...
Approximation Algorithms for Degree-Constrained Minimum-Cost Network-Design Problems (2001)
R. Ravi, Madhav V. Marathe, S. S. Ravi, Daniel J. Rosenkrantz
We study network-design problems with two different design objectives: the total cost of the edges and nodes in the network and the maximum degree of any node in the network. A prototypical example...
Approximation Algorithms for a Capacitated Network Design Problem (2001)
R. Hassin, R. Ravi, F. S. Salman
We study a network loading problem with applications in local access network design. Given a network, the problem is to route flow from several sources to a sink and to install capacity on the edges...
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Naveen Garg, Rohit Khandekar, Goran Konjevod, R. Ravi, F. S. Salman
We study two versions of the single sink buy-at-bulk network design problem. We are given a network and a single sink, and several sources which demand a certain amount of ow to be routed to the sink.
Approximation Algorithms for the Covering Steiner Problem (2001)
Goran Konjevod, R. Ravi, Aravind Srinivasan
The covering Steiner problem is a common generalization of the k-MST and the group Steiner problems: given an edge-weighted graph, with subsets of vertices called the groups, and a nonnegative...
In this paper, we present a new bicriteria approximation algorithm for the degreebounded minimum spanning tree problem. In this problem, we are given an undirected graph, a nonnegative cost function...
In this paper, we present a new bicriteria approximation algorithm for the degreebounded minimum spanning tree problem. In this problem, we are given an undirected graph, a nonnegative cost function...
A Polynomial Time Approximation Scheme for Minimum Routing Cost Spanning Trees (2000)
Bang Ye Wu, Vineet Bafna, R. Ravi, Chuan Yi Tang
Given an undirected graph with nonnegative costs on the edges, the routing cost of any of its spanning trees is the sum over all pairs of vertices of the cost of the path between the pair in the...
The p-Neighbor k-Center Problem (2000)
The k-center problem with triangle inequality is that of placing k center nodes in a weighted undirected graph in which the edge weights obey the triangle inequality, so that the maximum distance of...
Design Strategies for Optimal Multiplier Circuits (2000)
Charles Martel, Vojin Oklobdzija, R. Ravi, Paul F. Stelling
We present new design and analysis techniques for the synthesis of fast parallel multiplier circuits. In [4], Oklobdzija, Villeger, and Lui suggested a new approach, the Three Dimensional Method...
Parallelizing Elimination Orders with Linear Fill (2000)
Claudson Bornstein, Bruce Maggs, Gary Miller, R. Ravi
This paper presents an algorithm for finding parallel elimination orders for Gaussian elimination. Viewing a system of equations as a graph, the algorithm can be applied directly to interval graphs...
Computing similarity between RNA strings (2000)
Vineet Bafna, S. Muthukrishnan, R. Ravi
Ribonucleic acid (RNA) strings are strings over the four-letter alphabet fA; C; G;Ug with a secondary structure of base-pairing between A0U and C 0 G pairs in the string 1 . Edges are drawn between...
On 2-Coverings and 2-Packings of Laminar Families (2000)
. Let H be a laminar family of subsets of a groundset V . A k-cover of H is a multiset C of edges on V such that for every subset S in H, C has at least k edges that have exactly one end in S. A...
Approximating Maximum Leaf Spanning Trees in Almost Linear Time (2000)
Given an undirected graph, finding a spanning tree of the graph with maximum number of leaves is MAX SNP-complete. In this paper we give a new greedy 3-approximation algorithm for maximum-leaf...
Reconstructing Flow Paths (2000)
M. Conforti, R. Hassin, R. Ravi
For an undirected graph G = (V; E), the edge connectivity values between every pair of nodes of G can be recorded in a flow-equivalent tree that contains the edge connectivity value for a linear...
On 2-Coverings and 2-Packings of Laminar Families (2000)
Let H be a laminar family of subsets of a groundset V . A k-cover of H is a multiset of edges, C, such that for every subset S in H, C has at least k edges (counting multiplicities) that have exactly...
A Polynomial Time Approximation Scheme for Minimum Routing Cost Spanning Trees (2000)
Bang Ye Wu, Vineet Bafna, R. Ravi, Chuan Yi Tang
Given an undirected graph with nonnegative costs on the edges, the routing cost of any of its spanning trees is the sum over all pairs of vertices of the cost of the path between the pair in the...
In this paper, we present a new bicriteria approximation algorithm for the degree-bounded minimum spanning tree problem. In this problem, we are given an undirected graph, a nonnegative cost function...
A polylogarithmic approximation algorithm for the group Steiner tree problem (2000)
Naveen Garg, Goran Konjevod, R. Ravi
Given a weighted graph with some subsets of vertices called groups, the group Steiner tree problem is to nd a minimum-weight subgraph which contains at least one vertex from each group. We give a...
The Power of Local Optimization: Approximation Algorithms for Maximum-Leaf Spanning Tree (2000)
Given an undirected graph G, finding a spanning tree of G with the maximum number of leaves is NP-complete [5]. We use the simple technique of local optimization to provide the first approximation...
A nearly best-possible approximation algorithm for node-weighted Steiner trees (2000)
We give the first approximation algorithm for the node-weighted Steiner tree problem. Its performance guarantee is within a constant factor of the best possible unless ~ P ' NP . Our algorithm...
Approximation Algorithms for Certain Network Improvement Problems (2000)
Sven O. Krumke, R. Ravi, S. S. Ravi
. We study budget constrained network upgrading problems. Such problems aim at nding optimal strategies for improving a network under some cost measure subject to certain budget constraints. Given an...
On Approximating Planar Metrics by Tree Metrics (1999)
Goran Konjevod, R. Ravi, F. Sibel Salman
We connect the results of Bartal [4] on probabilistic approximation of metric spaces by tree metrics, and Klein, Plotkin and Rao [11] on decompositions of graphs without small K s;s minors (such as...
An Approximation Algorithm for the Covering Steiner Problem (1999)
The covering Steiner tree problem is a common generalization of the k-MST and the group Steiner problems: Given an edge weighted graph, with subsets of vertices called the groups, and a requirement...
A polylogarithmic approximation algorithm for the group Steiner tree problem (1999)
Naveen Garg, Goran Konjevod, R. Ravi
The group Steiner tree problem is a generalization of the Steiner tree problem where we are given several subsets (groups) of vertices in a weighted graph, and the goal is to find a minimum-weight...
Semi-Definite Relaxations for Minimum Bandwidth and other Vertex-Ordering problems (1999)
Avrim Blum, Goran Konjevod, R. Ravi, Santosh Vempala
We present simple semi-definite programming relaxations for the NP-hard minimum bandwidth and minimum length linear ordering problems. We then show how these relaxations can be rounded in a natural...
On 2-Coverings and 2-Packings of Laminar Families (1999)
Let H be a laminar family of subsets of a groundset V . A k-cover of H is a multiset of edges, C, such that for every subset S in H, C has at least k edges (counting multiplicities) that have exactly...
On 2-Coverings and 2-Packings of Laminar Families (1999)
Let H be a laminar family of subsets of a groundset V . A k-cover of H is a multiset of edges, C, such that for every subset S in H, C has at least k edges (counting multiplicities) that have exactly...
Approximation Algorithms for the Multiple Knapsack Problem with Assignment Restrictions (1999)
M. Dawande, J. Kalagnanam, P. Keskinocak, R. Ravi, F. S. Salman
Motivated by a real world application, we study the multiple knapsack problem with assignment restrictions (MKAR): We are given a set of items N = f1; : : : ; ng and a set of knapsacks M = f1; : : :...
Improving Minimum Cost Spanning Trees by Upgrading Nodes (1999)
S. O. Krumke, M. V. Marathe, H. Noltemeier, R. Ravi, S. S. Ravi, R. Sundaram, ...
We study budget constrained network upgrading problems. We are given an undirected edge weighted graph G = (V; E) where node v 2 V can be upgraded at a cost of c(v). This upgrade reduces the weight...
Semi-Definite Relaxations for Minimum Bandwidth and other Vertex-Ordering problems (1998)
Avrim Blum, Goran Konjevod, R. Ravi, Santosh Vempala
We present simple semi-definite programming relaxations for the NP-hard minimum bandwidth and minimum length linear ordering problems. We then show how these relaxations can be rounded in a natural...
Semi-Definite Relaxations for Minimum Bandwidth and other Vertex-Ordering problems (1998)
Avrim Blum, Goran Konjevod, R. Ravi, Santosh Vempala
We present simple semi-definite programming relaxations for the NP-hard minimum bandwidth and minimum length linear ordering problems. We then show how these relaxations can be rounded in a natural...
Semi-Definite Relaxations for Minimum Bandwidth and other Vertex-Ordering problems (1998)
Avrim Blum, Goran Konjevod, R. Ravi, Santosh Vempala
We present simple semi-definite programming relaxations for the NP-hard minimum bandwidth and minimum length linear ordering problems. We then show how these relaxations can be rounded in a natural...
Semi-Definite Relaxations for Minimum Bandwidth and other Vertex-Ordering problems (1998)
Avrim Blum, Goran Konjevod, R. Ravi, Santosh Vempala
We present simple semi-definite programming relaxations for the NP-hard minimum bandwidth and minimum length linear ordering problems. We then show how these relaxations can be rounded in a natural...
Semi-Definite Relaxations for Minimum Bandwidth and other Vertex-Ordering problems (1998)
Avrim Blum, Goran Konjevod, R. Ravi, Santosh Vempala
We present simple semi-definite programming relaxations for the NP-hard minimum bandwidth and minimum length linear ordering problems. We then show how these relaxations can be rounded in a natural...
Semi-Definite Relaxations for Minimum Bandwidth and other Vertex-Ordering problems (1998)
Avrim Blum, Goran Konjevod, R. Ravi, Santosh Vempala
We present simple semi-definite programming relaxations for the NP-hard minimum bandwidth and minimum length linear ordering problems. We then show how these relaxations can be rounded in a natural...
Semi-Definite Relaxations for Minimum Bandwidth and other Vertex-Ordering problems (1998)
Avrim Blum, Goran Konjevod, R. Ravi, Santosh Vempala
We present simple semi-definite programming relaxations for the NP-hard minimum bandwidth and minimum length linear ordering problems. We then show how these relaxations can be rounded in a natural...
Semi-Definite Relaxations for Minimum Bandwidth and other Vertex-Ordering problems (1998)
Avrim Blum, Goran Konjevod, R. Ravi, Santosh Vempala
We present simple semi-definite programming relaxations for the NP-hard minimum bandwidth and minimum length linear ordering problems. We then show how these relaxations can be rounded in a natural...
Semi-Definite Relaxations for Minimum Bandwidth and other Vertex-Ordering problems (1998)
Avrim Blum, Goran Konjevod, R. Ravi, Santosh Vempala
We present simple semi-definite programming relaxations for the NP-hard minimum bandwidth and minimum length linear ordering problems. We then show how these relaxations can be rounded in a natural...
Approximation Algorithms for Network Problems (1998)
Contents 1 Basic Graph Theory and Shortest-Paths Algorithms 1 1.1 Graph theory terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 The running time of algorithms . . ....
Improving Spanning Trees by Upgrading Nodes (1998)
S. O. Krumke, M. V. Marathe, H. Noltemeir, R. Ravi, S. Ravi
Id: upgrade.tex,v 2.2 1997#09#18 13:14:08 krumke Exp wirth We study bottleneck constrained network upgrading problems.We are given an edge weighted graph G =#V;E# where node v 2 V can be upgraded at...
Bicriteria Network Design Problems (1998)
Marathe, Madhav V., Ravi, R., Sundaram, Ravi, Ravi, S. S., Rosenkrantz, Daniel J., Hunt III, Harry B.
We study a general class of bicriteria network design problems. A generic problem in this class is as follows: Given an undirected graph and two minimization objectives (under different cost...
An Approximation Algorithm for Minimum-Cost Vertex-Connectivity Problems (1998)
We present an approximation algorithm for solving graph problems in which a low-cost set of edges must be selected that has certain vertex-connectivity properties. In the survivable network design...
Service-Constrained Network Design Problems (1998)
Madhav V. Marathe, R. Ravi, Ravi Sundaram
. Several practical instances of network design problems often require the network to satisfy multiple constraints. In this paper, we focus on the following problem (and its variants): find a...
The Power of Local Optimization: Approximation Algorithms for Maximum-Leaf Spanning Tree (1998)
Given an undirected graph G, finding a spanning tree of G with the maximum number of leaves is NP-complete [5]. We use the simple technique of local optimization to provide the first approximation...