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107 results on '"Rajan, Deepak"'

2. Byzantine-Resilient Locally Optimum Detection Using Collaborative Autonomous Networks

Author

Kailkhura, Bhavya, Ray, Priyadip, Rajan, Deepak, Yen, Anton, Barnes, Peter, and Goldhahn, Ryan

Subjects
Computer Science - Systems and Control, Statistics - Other Statistics
Abstract

In this paper, we propose a locally optimum detection (LOD) scheme for detecting a weak radioactive source buried in background clutter. We develop a decentralized algorithm, based on alternating direction method of multipliers (ADMM), for implementing the proposed scheme in autonomous sensor networks. Results show that algorithm performance approaches the centralized clairvoyant detection algorithm in the low SNR regime, and exhibits excellent convergence rate and scaling behavior (w.r.t. number of nodes). We also devise a low-overhead, robust ADMM algorithm for Byzantine-resilient detection, and demonstrate its robustness to data falsification attacks., Comment: Proceedings of the 2017 IEEE International Workshop on Computational Advances in Multi-Sensor Adaptive Processing (CAMSAP 2017), 10.-13. December 2017, Curacao, Dutch Antilles

Published
2018

3. Optimal Hierarchical Layouts for Cache-Oblivious Search Trees

Author

Lindstrom, Peter and Rajan, Deepak

Subjects
Computer Science - Data Structures and Algorithms
Abstract

This paper proposes a general framework for generating cache-oblivious layouts for binary search trees. A cache-oblivious layout attempts to minimize cache misses on any hierarchical memory, independent of the number of memory levels and attributes at each level such as cache size, line size, and replacement policy. Recursively partitioning a tree into contiguous subtrees and prescribing an ordering amongst the subtrees, Hierarchical Layouts generalize many commonly used layouts for trees such as in-order, pre-order and breadth-first. They also generalize the various flavors of the van Emde Boas layout, which have previously been used as cache-oblivious layouts. Hierarchical Layouts thus unify all previous attempts at deriving layouts for search trees. The paper then derives a new locality measure (the Weighted Edge Product) that mimics the probability of cache misses at multiple levels, and shows that layouts that reduce this measure perform better. We analyze the various degrees of freedom in the construction of Hierarchical Layouts, and investigate the relative effect of each of these decisions in the construction of cache-oblivious layouts. Optimizing the Weighted Edge Product for complete binary search trees, we introduce the MinWEP layout, and show that it outperforms previously used cache-oblivious layouts by almost 20%., Comment: Extended version with proofs added to the appendix

Published
2013

5. Spinal Epidural Hematoma--The Great Mimicker: A Case Series.

Author

Karapparambil, Vineeth C., Poovathumparambil, Venugopalan, Kumar, Abhiram A., Pilathodan, Ahammed Shaheem, and Rajan, Deepak

Subjects
SPINAL epidural hematoma, MYELODYSPLASTIC syndromes, IATROGENIC diseases, SYMPTOMS, SPINAL cord diseases
Abstract

Spontaneous spinal epidural hematoma (SSEH) refers to the occurrence of spontaneous bleeding into the epidural space of the spinal cord without trauma or any iatrogenic procedures that result in compressive myelopathy. It is a rare condition that presents with acute onset neck pain or back pain with neurological symptoms. Clinical presentation will be variable, and the occurrence of neurological symptoms may be delayed depending on the level and extent of involvement of the bleed. So, this condition can mimic many other diagnoses, and unless diagnosed and managed promptly, the patient will have a poor outcome. In this case report, we describe three cases that had varying presentations and were initially misleading. [ABSTRACT FROM AUTHOR]

Published
2024
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6. Fast Nearest Neighbor Search on Large Time-Evolving Graphs

Author

Akoglu, Leman, Khandekar, Rohit, Kumar, Vibhore, Parthasarathy, Srinivasan, Rajan, Deepak, Wu, Kun-Lung, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Kobsa, Alfred, Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Goebel, Randy, Series editor, Tanaka, Yuzuru, Series editor, Wahlster, Wolfgang, Series editor, Siekmann, Jörg, Series editor, Calders, Toon, editor, Esposito, Floriana, editor, Hüllermeier, Eyke, editor, and Meo, Rosa, editor

Published
2014
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7. FLEX: A Slot Allocation Scheduling Optimizer for MapReduce Workloads

Author

Wolf, Joel, Rajan, Deepak, Hildrum, Kirsten, Khandekar, Rohit, Kumar, Vibhore, Parekh, Sujay, Wu, Kun-Lung, Balmin, Andrey, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Gupta, Indranil, editor, and Mascolo, Cecilia, editor

Published
2010
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8. COLA: Optimizing Stream Processing Applications via Graph Partitioning

Author

Khandekar, Rohit, Hildrum, Kirsten, Parekh, Sujay, Rajan, Deepak, Wolf, Joel, Wu, Kun-Lung, Andrade, Henrique, Gedik, Buğra, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Bacon, Jean M., editor, and Cooper, Brian F., editor

Published
2009
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9. Job Admission and Resource Allocation in Distributed Streaming Systems

Author

Wolf, Joel, Bansal, Nikhil, Hildrum, Kirsten, Parekh, Sujay, Rajan, Deepak, Wagle, Rohit, Wu, Kun-Lung, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Frachtenberg, Eitan, editor, and Schwiegelshohn, Uwe, editor

Published
2009
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10. SODA: An Optimizing Scheduler for Large-Scale Stream-Based Distributed Computer Systems

Author

Wolf, Joel, Bansal, Nikhil, Hildrum, Kirsten, Parekh, Sujay, Rajan, Deepak, Wagle, Rohit, Wu, Kun-Lung, Fleischer, Lisa, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Issarny, Valérie, editor, and Schantz, Richard, editor

Published
2008
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11. On Temperature-Aware Scheduling for Single-Processor Systems

Author

Rajan, Deepak, Yu, Philip S., Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Aluru, Srinivas, editor, Parashar, Manish, editor, Badrinath, Ramamurthy, editor, and Prasanna, Viktor K., editor

Published
2007
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13. Post-COVID-19 manifestations-are they a matter of concern?

Author

Rajan, Deepak, primary, Raheela, Ameena Subair, additional, Muduvana, Preetha, additional, Chirammal, Sachin Kuthirummal, additional, Choorickadu, Bhagyalakshmi, additional, Purayi, Vismaya Pattarkatt Puthiya, additional, Chelangara, Chathurya, additional, Mullan, Akshay, additional, Chandran, Akshay, additional, Ariyeri, Shanil, additional, and Kandiyantavida, Lenin Thazhe, additional

Published
2022
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15. Role of Operating Flexibility in Planning Studies

Author

Alvarez, Antonio, primary, Dong, Will, additional, Moradzadeh, Ben, additional, Nolen, Carl, additional, Anderson, Rob, additional, Edmunds, Thomas, additional, Grosh, Josh, additional, Rajan, Deepak, additional, Carden, Kevin, additional, Wintermantel, Nick, additional, Patel, Parth, additional, Krasny, Alex, additional, Tuohy, Aidan, additional, Ela, Erik, additional, Lannoye, Eamonn, additional, and Wang, Qin, additional

Published
2017
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22. COVID-19: timely action to prevent local transmission: a success story from Kannur District, Kerala

Author

Saraswathy, Anitha Subhadra, primary, Raheela, Ameena Subair, additional, Sanya, Rameela, additional, Morakkan, Veena Vandichalil, additional, Paleri, Bejoy Chalil, additional, Koppentavida, Murali, additional, Kuriakose, Steena, additional, Rajan, Deepak, additional, Konoth, Shaj Mullankandy, additional, Muduvana, Preetha, additional, Kumaran, Jayasree Anandabhavan, additional, Naik, Narayan, additional, Koomullil, Sanoj Akkanissery, additional, Radhakrishnan, Nithin, additional, and Rajagopalan, Rahul Kizhakkemadathil, additional

Published
2021
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40. Scheduling with Setup Costs and Monotone Penalties

Author

Khandekar, Rohit, Hildrum, Kirsten, Rajan, Deepak, and Wolf, Joel

Subjects
000 Computer science, knowledge, general works, Computer Science, Computer Science::Data Structures and Algorithms, Computer Science::Operating Systems
Abstract

We consider single processor preemptive scheduling with job-dependent setup times. In this model, a job-dependent setup time is incurred when a job is started for the first time, and each time it is restarted after preemption. This model is a common generalization of preemptive scheduling, and actually of non-preemptive scheduling as well. The objective is to minimize the sum of any general non-negative, non-decreasing cost functions of the completion times of the jobs -- this generalizes objectives of minimizing weighted flow time, flow-time squared, tardiness or the number of tardy jobs among many others. Our main result is a randomized polynomial time O(1)-speed O(1)-approximation algorithm for this problem. Without speedup, no polynomial time finite multiplicative approximation is possible unless P=NP. We extend the approach of Bansal et al. (FOCS 2007) of rounding a linear programming relaxation which accounts for costs incurred due to the non-preemptive nature of the schedule. A key new idea used in the rounding is that a point in the intersection polytope of two matroids can be decomposed as a convex combination of incidence vectors of sets that are independent in both matroids. In fact, we use this for the intersection of a partition matroid and a laminar matroid, in which case the decomposition can be found efficiently using network flows. Our approach gives a randomized polynomial time offline O(1)-speed O(1)-approximation algorithm for the broadcast scheduling problem with general cost functions as well.

Published
2012
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43. Bounded Size Graph Clustering with Applications to Stream Processing

Author

Khandekar, Rohit, Hildrum, Kirsten, Parekh, Sujay, Rajan, Deepak, Sethuraman, Jay, and Wolf, Joel

Subjects
000 Computer science, knowledge, general works, Computer Science, MathematicsofComputing_DISCRETEMATHEMATICS
Abstract

We introduce a graph clustering problem motivated by a stream processing application. Input to our problem is an undirected graph with vertex and edge weights. A cluster is a subset of the vertices. The {\em size} of a cluster is defined as the total vertex weight in the subset plus the total edge weight at the boundary of the cluster. The bounded size graph clustering problem ($\GC$) is to partition the vertices into clusters of size at most a given budget and minimize the total edge-weight across the clusters. In the {\em multiway cut} version of the problem, we are also given a subset of vertices called {\em terminals}. No cluster is allowed to contain more than one terminal. Our problem differs from most of the previously studied clustering problems in that the number of clusters is not specified. We first show that the feasibility version of the multiway cut $\GC$ problem, i.e., determining if there exists a clustering with bounded-size clusters satisfying the multiway cut constraint, can be solved in polynomial time. Our algorithm is based on the min-cut subroutine and an uncrossing argument. This result is in contrast with the NP-hardness of the min-max multiway cut problem, considered by Svitkina and Tardos (2004), in which the number of clusters must equal the number of terminals. Our results for the feasibility version also generalize to any symmetric submodular function. We next show that the optimization version of $\GC$ is NP-hard by showing an approximation-preserving reduction from the $\frac 13$-balanced cut problem. Our main result is an $O(\log^2 n)$-approximation to the optimization version of the multiway cut $\GC$ problem violating the budget by an $O(\log n)$ factor, where $n$ denotes the number of vertices. Our algorithm is based on a set-cover-like greedy approach which iteratively computes bounded-size clusters to maximize the number of new vertices covered.

Published
2009
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44. House dust mite allergy is a major cause for respiratory symptoms and sleep disorders in young children.

Author

Rajan, Deepak and Khan, Sujoy

Subjects
*HOUSE dust mites, *WHEEZE, *SLEEP disorders, *ATOPY, *ALLERGIES, *SYMPTOMS, *SOFT toys
Abstract

Our report using specific IgE tests on adults and children with persistent mild/moderate-severe rhinitis/asthma in the eastern part of the Indian subcontinent had shown that 60% of children were sensitised to dust mite allergens [Figure 1] and [Table 1].[[4]] Almost half of the children were polysensitised [see [Figure 1]], with house dust mite, cockroach and common ragweed (c.f. Parthenium hysterophorus) allergens being the major sensitisers in these children. Sir, We read with interest the paper by Sastry et al.[[1]] on the effect of indoor environment where sleeping with a stuffed toy was found to be associated with sleep disorders independent of wheeze in young children. [Extracted from the article]

Published
2022
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49. Scheduling with Setup Costs and Monotone Penalties

Author

Rohit Khandekar and Kirsten Hildrum and Deepak Rajan and Joel Wolf, Khandekar, Rohit, Hildrum, Kirsten, Rajan, Deepak, Wolf, Joel, Rohit Khandekar and Kirsten Hildrum and Deepak Rajan and Joel Wolf, Khandekar, Rohit, Hildrum, Kirsten, Rajan, Deepak, and Wolf, Joel

Abstract

We consider single processor preemptive scheduling with job-dependent setup times. In this model, a job-dependent setup time is incurred when a job is started for the first time, and each time it is restarted after preemption. This model is a common generalization of preemptive scheduling, and actually of non-preemptive scheduling as well. The objective is to minimize the sum of any general non-negative, non-decreasing cost functions of the completion times of the jobs -- this generalizes objectives of minimizing weighted flow time, flow-time squared, tardiness or the number of tardy jobs among many others. Our main result is a randomized polynomial time O(1)-speed O(1)-approximation algorithm for this problem. Without speedup, no polynomial time finite multiplicative approximation is possible unless P=NP. We extend the approach of Bansal et al. (FOCS 2007) of rounding a linear programming relaxation which accounts for costs incurred due to the non-preemptive nature of the schedule. A key new idea used in the rounding is that a point in the intersection polytope of two matroids can be decomposed as a convex combination of incidence vectors of sets that are independent in both matroids. In fact, we use this for the intersection of a partition matroid and a laminar matroid, in which case the decomposition can be found efficiently using network flows. Our approach gives a randomized polynomial time offline O(1)-speed O(1)-approximation algorithm for the broadcast scheduling problem with general cost functions as well.

Published
2012
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50. Bounded Size Graph Clustering with Applications to Stream Processing

Author

Rohit Khandekar and Kirsten Hildrum and Sujay Parekh and Deepak Rajan and Jay Sethuraman and Joel Wolf, Khandekar, Rohit, Hildrum, Kirsten, Parekh, Sujay, Rajan, Deepak, Sethuraman, Jay, Wolf, Joel, Rohit Khandekar and Kirsten Hildrum and Sujay Parekh and Deepak Rajan and Jay Sethuraman and Joel Wolf, Khandekar, Rohit, Hildrum, Kirsten, Parekh, Sujay, Rajan, Deepak, Sethuraman, Jay, and Wolf, Joel

Abstract

We introduce a graph clustering problem motivated by a stream processing application. Input to our problem is an undirected graph with vertex and edge weights. A cluster is a subset of the vertices. The {\em size} of a cluster is defined as the total vertex weight in the subset plus the total edge weight at the boundary of the cluster. The bounded size graph clustering problem ($\GC$) is to partition the vertices into clusters of size at most a given budget and minimize the total edge-weight across the clusters. In the {\em multiway cut} version of the problem, we are also given a subset of vertices called {\em terminals}. No cluster is allowed to contain more than one terminal. Our problem differs from most of the previously studied clustering problems in that the number of clusters is not specified. We first show that the feasibility version of the multiway cut $\GC$ problem, i.e., determining if there exists a clustering with bounded-size clusters satisfying the multiway cut constraint, can be solved in polynomial time. Our algorithm is based on the min-cut subroutine and an uncrossing argument. This result is in contrast with the NP-hardness of the min-max multiway cut problem, considered by Svitkina and Tardos (2004), in which the number of clusters must equal the number of terminals. Our results for the feasibility version also generalize to any symmetric submodular function. We next show that the optimization version of $\GC$ is NP-hard by showing an approximation-preserving reduction from the $\frac 13$-balanced cut problem. Our main result is an $O(\log^2 n)$-approximation to the optimization version of the multiway cut $\GC$ problem violating the budget by an $O(\log n)$ factor, where $n$ denotes the number of vertices. Our algorithm is based on a set-cover-like greedy approach which iteratively computes bounded-size clusters to maximize the number of new vertices covered.

Published
2009
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