Amitabh Trehan

Amitabh Trehan
Loughborough University | Lough · Department of Computer Science

Ph.D.

About

35
Publications
7,299
Reads
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368
Citations
Introduction
My broad research is in CS theory and algorithms, especially problems of real world and human engineered systems; Distributed algorithms, networks(static/dynamic), graph theory, and game theory. Current work includes designing distributed algorithms for robustness/self-healing/self-* in dynamic networks under attack, distributed computing and distributed verification, and game theoretic and other protocols for evolving networks, such as social networks or distributed systems (P2P networks etc).
Additional affiliations
October 2013 - present
Queen's University Belfast
Position
  • Research Assistant
April 2013 - October 2013
Hebrew University of Jerusalem
Position
  • I-CORE Postdoctoral Fellow
Description
  • Isreali Center of Research Excellence in Distiributing Computing.
October 2010 - present
Technion - Israel Institute of Technology
Position
  • PostDoc Position
Education
August 2004 - May 2010
University of New Mexico
Field of study
  • Computer Science
August 2000 - December 2002
Indian Institute of Technology Delhi
Field of study
  • Computer Applications
August 1996 - December 1999
Indira Gandhi National Open University, New Delhi, India
Field of study
  • Computer Applications

Publications

Publications (35)
Article
Full-text available
In distributed network algorithms, network flooding algorithm is considered one of the simplest and most fundamental algorithms. This research specifies the basic synchronous memory-less network flooding algorithm where nodes on the network don’t have memory, for any fixed size of network, in Linear Temporal Logic. The specification can be customiz...
Preprint
Basic synchronous flooding proceeds in rounds. Given a finite undirected (network) graph $G$, a set of sources $I \subseteq G$ initiate flooding in the first round by every node in $I$ sending the same message to all of its neighbours. In each subsequent round, nodes send the message to all of their neighbours from which they did not receive the me...
Preprint
Full-text available
Flooding is among the simplest and most fundamental of all distributed network algorithms. A node begins the process by sending a message to all its neighbours and the neighbours, in the next round forward the message to all the neighbours they did not receive the message from and so on. We assume that the nodes do not keep a record of the flooding...
Conference Paper
Flooding is a fundamental distributed algorithms technique. Consider the following flooding process, for simplicity, in a synchronous message passing network: A distinguished node begins the flooding process by sending the (same) message to all its neighbours in the first round. In subsequent rounds, every node receiving the message relays a copy o...
Article
Full-text available
This paper looks at the question of designing distributed algorithms for the setting of compact memory i.e. sublinear (in $n$ - the number of nodes) bits for connected networks of arbitrary topologies. The nodes in our networks may have much lower internal memory (say, $O(poly\log n)$) as compared to the number of their possible neighbours. This im...
Conference Paper
Fault tolerance is an important challenge for supporting critical big data analytic operations. Most existing solutions only provide fault tolerant data replication, requiring failed queries to be restarted. This approach is insufficient for long-running time-sensitive analytic queries, due to lost query progress. Several solutions provide intra-qu...
Article
Full-text available
We present a fully-distributed self-healing algorithm dex that maintains a constant degree expander network in a dynamic setting. To the best of our knowledge, our algorithm provides the first efficient distributed construction of expanders—whose expansion properties hold deterministically—that works even under an all-powerful adaptive adversary th...
Conference Paper
Existing compact routing schemes, e.g., Thorup and Zwick [SPAA 2001] and Chechik [PODC 2013], often have no means to tolerate failures, once the system has been setup and started. This paper presents, to our knowledge, the first self-healing compact routing scheme. Besides, our schemes are developed for low memory nodes, i.e., nodes need only O(log...
Article
Existing compact routing schemes, e.g., Thorup and Zwick [SPAA 2001] and Chechik [PODC 2013], often have no means to tolerate failures, once the system has been setup and started. This paper presents, to our knowledge, the first self-healing compact routing scheme. Besides, our schemes are developed for low memory nodes, i.e., nodes need only $O(\l...
Article
We consider the problem of self-healing in reconfigurable networks e.g., peer-to-peer and wireless mesh networks. For such networks under repeated attack by an omniscient adversary, we propose a fully distributed algorithm, Xheal, that maintains good expansion and spectral properties of the network, while keeping the network connected. Moreover, Xh...
Conference Paper
Electing a leader is a fundamental task in distributed computing. In its implicit version, only the leader must know who is the elected leader. This article focuses on studying the message and time complexity of randomized implicit leader election in synchronous distributed networks. Surprisingly, the most “obvious” complexity bounds have not been...
Conference Paper
Full-text available
We analyze ways by which people decompose into groups in distributed systems. We are interested in systems in which an agent can increase its utility by connecting to other agents, but must also pay a cost that increases with the size of the system. The right balance is achieved by the right size group of agents. We formulate and analyze three intu...
Article
Full-text available
Many modern networks are reconfigurable, in the sense that the topology of the network can be changed by the nodes in the network. For example, peer-to-peer, wireless and ad-hoc networks are reconfigurable. More generally, many social networks, such as a company's organizational chart; infrastructure networks, such as an airline's transportation ne...
Article
This paper concerns randomized leader election in synchronous distributed networks. A distributed leader election algorithm is presented for complete n-node networks that runs in O(1) rounds and (with high probability) takes only \(O(\sqrt{n}\log^{3/2} n)\) messages to elect a unique leader (with high probability). This algorithm is then extended t...
Conference Paper
In distributed networks, it is often useful for the nodes to be aware of dense subgraphs, e.g., such a dense subgraph could reveal dense substructures in otherwise sparse graphs (e.g. the World Wide Web or social networks); these might reveal community clusters or dense regions for possibly maintaining good communication infrastructure. In this wor...
Conference Paper
Full-text available
In distributed networks, some groups of nodes may have more inter-connections, perhaps due to their larger bandwidth availability or communication requirements. In many scenarios, it may be useful for the nodes to know if they form part of a dense subgraph, e.g., such a dense subgraph could form a high bandwidth backbone for the network. In this wo...
Article
Full-text available
We present a fully-distributed self-healing algorithm DEX, that maintains a constant degree expander network in a dynamic setting. To the best of our knowledge, our algorithm provides the first efficient distributed construction of expanders --- whose expansion properties hold {\em deterministically} --- that works even under an all-powerful adapti...
Article
A traditional distributed system is often designed by some central manufacturer and owned by some central owner. However, increasingly, more modern distributed systems are composed of components, each owned by a different owner. Moreover, such systems are formed rather distributively, by people teaming up to pool their resources together. For examp...
Article
Full-text available
Modern networks are large, highly complex and dynamic. Add to that the mobility of the agents comprising many of these networks. It is difficult or even impossible for such systems to be managed centrally in an efficient manner. It is imperative for such systems to attain a degree of self-management. Self-healing i.e. the capability of a system in...
Conference Paper
Full-text available
A traditional distributed system was, usually, designed by some centralized manufacturer and owned by some central owner. On the other hand, many modern distributed systems (e.g., many Peer to Peer (P2P) networks) are formed when people team up to pool their resources together to form such a system. We aim to initiate an investigation into the way...
Article
Full-text available
Healing algorithms play a crucial part in distributed P2P networks where failures occur continuously and frequently. Several self-healing algorithms have been suggested recently [IPDPS'08, PODC'08, PODC'09, PODC'11] in a line of work that has yielded gradual improvements in the properties ensured on the graph. This work motivates a strong general p...
Article
Full-text available
We analyze ways by which people decompose into groups in distributed systems. We are interested in systems in which an agent can increase its utility by connecting to other agents, but must also pay a cost that increases with the size of the sys- tem. The right balance is achieved by the right size group of agents. We formulate and analyze three in...
Conference Paper
Full-text available
We address the problem of designing distributed algorithms for large scale networks that are robust to Byzantine faults. We consider a message passing, full information model: the adversary is malicious, controls a constant fraction of processors, and can view all messages in a round before sending out its own messages for that round. Furthermore,...
Article
Full-text available
We consider the problem of self-healing in reconfigurable networks (e.g. peer-to-peer and wireless mesh networks) that are under repeated attack by an omniscient adversary and propose a fully distributed algorithm, Xheal that maintains good expansion and spectral properties of the network, also keeping the network connected. Moreover, Xheal does th...
Conference Paper
Full-text available
We consider the problem of self-healing in peer-to-peer networks that are under repeated attack by an omniscient adversary. We assume that, over a sequence of rounds, an adversary either inserts a node with arbitrary connections or deletes an arbitrary node from the network. The network responds to each such change by quick “repairs,” which consist...
Conference Paper
We consider the problem of self-healing in peer-to-peer networks that are under repeated attack by an omniscient adversary. We assume that, over a sequence of rounds, an adversary either inserts a node with arbitrary connections or deletes an arbitrary node from the network. The network responds to each such change by quick "repairs," which consist...
Conference Paper
Full-text available
We consider the problem of self-healing in networks that are reconfigurable in the sense that they can change their topology during an attack. Our goal is to maintain connectivity in these networks, even in the presence of repeated adversarial node deletion, by carefully adding edges after each attack. We present a new algorithm, DASH, that provabl...
Article
Full-text available
We consider the problem of self-healing in peer-to-peer networks that are under repeated attack by an omniscient adversary. We assume that the following process continues for up to n rounds where n is the total number of nodes initially in the network: the adversary deletes an arbitrary node from the network, then the network responds by quickly ad...
Article
Full-text available
Real-world systems are often exposed to failures where those studied theoretically are not: neuron cells in the brain can die or fail, re-sources in a peer-to-peer network can break down or become corrupt, species can disappear from and environment, and so forth. In all cases, for the system to keep running as it did before the failure occurred, or...
Article
Full-text available
W E present two distributed algorithms for self-healing in networks that are reconfig-urable (such as peer-to-peer networks) in the sense that they can change their topol-ogy during an attack. Self-healing seeks to maintain connectivity and possibly other useful properties in the face of repeated attacks by an adversary, that in our model, is assum...
Article
Full-text available
This paper describes our efforts to produce what is, to our knowledge, the first book typeset totally in an Indian language using L A T E X: Chhand Chhand par Kumkum, published by Prabhat Prakashan for Mahatma Gandhi Antarrashtriya Hindi Vishwavidyalaya (MGAHV). We used the devnag package, which made it possible to encode each chapter, including ve...
Article
All applied - as opposed to theoretical - systems are exposed to failures: neuron cells in the brain can die or fail, computers in a peer- to-pper network can berak down or become corrupt, species can disapear from and environment, and so forth. In all cases, for the system to keep running as it did before the failure occured, or to survive at all,...

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Projects

Project (1)
Project
EPSRC First grant 2017/18. To develop compact routing solutions in the self-healing model of distributed computing.