Indian Institute of Science

Displaying 1-40 of 123 results

  • White Papers // Jan 2014

    Prediction of Queue Waiting Times for Metascheduling on Parallel Batch Systems

    Prediction of queue waiting times of jobs submitted to production parallel batch systems is important to provide overall estimates to users and can also help meta-schedulers make scheduling decisions. In this paper, the authors have developed a framework for predicting ranges of queue waiting times for jobs by employing multi-class...

    Provided By Indian Institute of Science

  • White Papers // Dec 2013

    An Improved Outer Bound on the Storage-Repair-Bandwidth Tradeoff of Exact-Repair Regenerating Codes

    In this paper, the authors establish an improved outer bound on the storage-repair-bandwidth tradeoff of regenerating codes under exact repair. The result shows that in particular, it is not possible to construct exact-repair regenerating codes that asymptotically achieve the tradeoff that holds for functional repair. While this had been shown...

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  • White Papers // Oct 2013

    A Closer Look at Multiple-Forking: Leveraging (In)dependence for a Tighter Bound

    The machinery of oracle replay attack of Pointcheval and Stern [PS00] plays a pivotal role in the security argument of a large class of signature schemes [ElG85, Sch91, Oka93]. In the basic version of replay attack, one runs the adversary twice on related inputs in order to solve the underlying...

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  • White Papers // Apr 2013

    Capacity Bounds for the Gaussian X Channel

    The authors consider bounds for the capacity region of the Gaussian X Channel (XC), a system consisting of two transmit-receive pairs, where each transmitter communicates with both the receivers. They first classify the XC into two classes, the strong XC and the mixed XC. In the strong XC, either the...

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  • White Papers // Mar 2013

    Perormance Analysis of a Node Monitoring Protocol in Ubiquitous Networks

    The proliferation of the ubiquitous applications in different sphere of life like ubiquitous health monitoring system, and ubiquitous learning system demands the network monitoring, to check whether the nodes are getting the promised resources and inputs. Dynamicity and heterogeneity of the ubiquitous network adds challenges to the monitoring of a...

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  • White Papers // Mar 2013

    Measurement Based Impromptu Deployment of a Multi-Hop Wireless Relay Network

    The authors study the problem of optimal sequential ("As-you-go") deployment of wireless relay nodes, as a person walks along a line of random length (with a known distribution). The objective is to create an impromptu multi-hop wireless network for connecting a packet source to be placed at the end of...

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  • White Papers // Mar 2013

    Wireless Network-Coded Multi-Way Relaying Using Latin Hyper-Cubes

    The two-stage protocol for physical layer network coding for the two-way relay channel first introduced in 2006, exploits the multiple access interference occurring at the relay so that the communication between the end nodes can be done using a two stage protocol. The paper deals with the information theoretic studies...

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  • White Papers // Mar 2013

    Improved IDS Using Layered CRFS With Logon Restrictions and Mobile Alerts Based on Deviant System Behaviour

    With the ever increasing number and diverse type of attacks, including new and previously unseen attacks, the effectiveness of an intrusion detection system is very important. Hence there is high demand to reduce the threat level in networks to ensure the data and services offered by them to be more...

    Provided By Indian Institute of Science

  • White Papers // Feb 2013

    SC-FDMA for Multiuser Communication on the Downlink

    Single-Carrier Frequency Division Multiple Access (SC-FDMA) has become a popular alternative to Orthogonal Frequency Division Multiple Access (OFDMA) in multiuser communication on the uplink. This is mainly due to the low Peak-to-Average Power Ratio (PAPR) of SC-FDMA compared to that of OFDMA. Long-Term Evolution (LTE) uses SC-FDMA on the uplink...

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  • White Papers // Jan 2013

    Language Based Security for Smartphones

    Install time permission model used in android, may provide users a control over their privacy and security and may reduce the impact of bugs and vulnerabilities in applications; however such a model becomes ineffective if users are uninformed about the behavior of these applications and their potential harms once an...

    Provided By Indian Institute of Science

  • White Papers // Jan 2013

    A Combinatorial Family of Near Regular LDPC Codes

    An elementary combinatorial Tanner graph construction for a family of near-regular Low Density Parity Check (LDPC) codes achieving high girth is presented. These codes are near regular in the sense that the degree of a left/right vertex is allowed to differ by at most one from the average. The construction...

    Provided By Indian Institute of Science

  • White Papers // Dec 2012

    Distributed Co-Phasing for Binary Consensus in Wireless Sensor Networks

    The authors address the problem of binary consensus over noisy, fading channels. They propose a new transmission model using Distributed Co-phasing that ensures the system to reach accurate consensus quite efficiently. They propose a simple linear update rule at nodes based on LMMSE and see that its performance is close...

    Provided By Indian Institute of Science

  • White Papers // Dec 2012

    Adaptive Scheduling in Real-Time Systems Through Period Adjustment

    Real-time system technology traditionally developed for safety critical systems, has now been extended to support multimedia systems and virtual reality. A large number of real-time application, related to multimedia and adaptive control system, require more flexibility than classical real-time theory usually permits. This paper proposes an efficient adaptive scheduling framework...

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  • White Papers // Dec 2012

    Information Capacity of an Energy Harvesting Sensor Node

    Energy harvesting sensor nodes are gaining popularity due to their ability to improve the network life time and are becoming a preferred choice supporting "Green Communication". In this paper, the authors focus on communicating reliably over an AWGN channel using such an energy harvesting sensor node. An important part of...

    Provided By Indian Institute of Science

  • White Papers // Dec 2012

    Throughput Analysis of Primary and Secondary Networks in a Shared IEEE 802.11 System

    In this paper, the authors analyze the coexistence of a primary and a secondary (cognitive) network when both networks use the IEEE 802.11 based distributed coordination function for medium access control. Specifically, they consider the problem of channel capture by a secondary network that uses spectrum sensing to determine the...

    Provided By Indian Institute of Science

  • White Papers // Nov 2012

    Resource Usage Monitoring in Clouds

    Monitoring of infrastructural resources in clouds plays a crucial role in providing application guarantees like performance, availability, and security. Monitoring is crucial from two perspectives - the cloud-user and the service provider. The cloud user's interest is in doing an analysis to arrive at appropriate Service-Level Agreement (SLA) demands and...

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  • White Papers // Sep 2012

    Modelling and Analysis of New Coolstreaming for P2P IPTV

    Peer to peer networks are being used extensively nowadays for file sharing, video on demand and live streaming. For IPTV, delay deadlines are more stringent compared to file sharing. Cool-streaming was the first P2P IPTV system. In this paper, the authors model New Cool-streaming (newer version of Cool-streaming) via a...

    Provided By Indian Institute of Science

  • White Papers // Sep 2012

    Bounds on the Sum-Rate Capacity of the Gaussian MIMO X Channel

    The authors consider the MIMO X Channel (XC), a system consisting of two transmit-receive pairs, where each transmitter communicates with both the receivers. Both the transmitters and receivers are equipped with multiple antennas. First, they derive an upper bound on the sum-rate capacity of the MIMO XC under individual power...

    Provided By Indian Institute of Science

  • White Papers // Aug 2012

    Decode-and-Forward Relay Beamforming for Secrecy With Imperfect CSI and Multiple Eavesdroppers

    Wireless transmissions, by their very nature, are vulnerable to eavesdropping. There has been considerable interest in the use of physical layer mechanisms to provide secure communications, whereby the eavesdropper gets no information while the intended receiver gets the information reliably. Wyner's work on secrecy capacity of discrete memoryless wiretap channels...

    Provided By Indian Institute of Science

  • White Papers // Jul 2012

    Factor Graph Based Joint Detection/Decoding for LDPC Coded Large-MIMO Systems

    In this paper, the authors employ message passing algorithms over graphical models to jointly detect and decode symbols transmitted over large Multiple-Input Multiple-Output (MIMO) channels with Low Density Parity Check (LDPC) coded bits. They adopt a factor graph based technique to integrate the detection and decoding operations. A Gaussian approximation...

    Provided By Indian Institute of Science

  • White Papers // Jul 2012

    Frequency Domain Turbo Equalization for MIMO-CPSC Systems With Large Delay Spreads

    In this paper, the authors consider low-complexity turbo equalization for Multiple-Input Multiple-Output (MIMO) Cyclic Prefixed Single Carrier (CPSC) systems in MIMO Inter-Symbol Interference (ISI) channels characterized by large delay spreads. A low-complexity graph based equalization is carried out in the frequency domain. Because of the reduction in correlation among the...

    Provided By Indian Institute of Science

  • White Papers // Jun 2012

    Secure Compute-and-Forward in a Bidirectional Relay

    Bidirectional relaying, where a relay helps two user nodes to exchange messages has been an active area of recent research. In the compute-and-forward strategy for bidirectional relaying, the relay computes a function of the two messages using the naturally-occurring sum of symbols simultaneously transmitted by user nodes in a Gaussian...

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  • White Papers // May 2012

    Diversity-Rate Trade-Off for Fading Channels With Power Control

    The authors consider a complex, additive, white Gaussian noise channel with flat fading. They study its diversity order vs transmission rate for some known power allocation schemes. The capacity region is divided into three regions. For one power allocation scheme, the diversity order is exponential throughout the capacity region. For...

    Provided By Indian Institute of Science

  • White Papers // May 2012

    LoadIQ: Learning to Identify Workload Phases From a Live Storage Trace

    Storage infrastructure in large-scale cloud data center environments must support applications with diverse, time-varying data access patterns while observing the quality of service. Deeper storage hierarchies induced by solid state and rotating media are enabling new storage management tradeoffs that do not apply uniformly to all application phases at all...

    Provided By Indian Institute of Science

  • White Papers // Apr 2012

    A Novel MCMC Algorithm for Near-Optimal Detection in Large-Scale Uplink Mulituser MIMO Systems

    In this paper, the authors propose a low-complexity algorithm based on Markov Chain Monte Carlo (MCMC) technique for signal detection on the uplink in large scale multiuser Multiple Input Multiple Output (MIMO) systems with tens to hundreds of antennas at the Base Station (BS) and similar number of uplink users....

    Provided By Indian Institute of Science

  • White Papers // Apr 2012

    Capacity of a Gaussian MAC with Energy Harvesting Transmit Nodes

    The authors consider a Gaussian Multiple Access Channel (GMAC) where the users are sensor nodes powered by energy harvesters. The energy harvesters may have finite or infinite buffer to store the harvested energy. First, they find the capacity region of a GMAC powered by transmit nodes with an infinite energy...

    Provided By Indian Institute of Science

  • White Papers // Apr 2012

    Relay Selection With Channel Probing for Geographical Forwarding in WSNs

    In a large Wireless Sensor Network (WSN) with sleep-wake cycling nodes, the authors are interested in the local decision problem faced by a node that has "Custody" of a packet and has to choose one among a set of next-hop relay nodes. Each of the relays is associated with a...

    Provided By Indian Institute of Science

  • White Papers // Mar 2012

    Wireless Network-Coded Three-Way Relaying Using Latin Cubes

    The design of modulation schemes for the physical layer network-coded three-way wireless relaying scenario is considered. The protocol employs two phases: Multiple Access (MA) phase and BroadCast (BC) phase with each phase utilizing one channel use. For the two-way relaying scenario, it was observed by Koike-Akino et al., that adaptively...

    Provided By Indian Institute of Science

  • White Papers // Mar 2012

    Performance Analysis of Adaptive Physical Layer Network Coding for Wireless Two-Way Relaying

    The analysis of modulation schemes for the physical layer network-coded two way relaying scenario is presented which employs two phases: Multiple access (MA) phase and BroadCast (BC) phase. It was shown by Koike-Akino et. al. that adaptively changing the network coding map used at the relay according to the channel...

    Provided By Indian Institute of Science

  • White Papers // Mar 2012

    On Secrecy Above Secrecy Capacity

    Information theoretic security is being widely studied in recent times. It provides fundamental limits of secret communication. Unlike in cryptography, the information theoretic techniques are not based on complexity of computational hardness of certain problems. Information theoretic security can also be used in a system in addition to cryptographic techniques...

    Provided By Indian Institute of Science

  • White Papers // Mar 2012

    Performance Analysis of Deterministic Key Allocation Schemes for Wireless Sensor Networks

    Because of the resource-constrained nature of Wireless Sensor Networks (WSNs), it is easier to use a security system based on symmetric key cryptography. However, the distribution and management of cryptographic keys pose challenges of their own. In this paper, the authors study some deterministic methods of distribution of keys to...

    Provided By Indian Institute of Science

  • White Papers // Mar 2012

    Wireless Network Coding for MIMO Two-Way Relaying Using Latin Rectangles

    The authors consider the two-way wireless relaying scenario shown with multiple antennas at the nodes, where data transfer takes place between the nodes A and B with the help of the relay R. It is assumed that all the three nodes operate in half-duplex mode, i.e., they cannot transmit and...

    Provided By Indian Institute of Science

  • White Papers // Mar 2012

    Cooperative Particle Swarm Optimization Based Receiver for Large-Dimension MIMO-ZPSC Systems

    In this paper, the authors propose a Cooperative Particle Swarm Optimization (CPSO) based channel estimation/equalization scheme for Multiple-Input Multiple-Output Zero-Padded Single-Carrier (MIMO-ZPSC) systems with large dimensions in frequency selective channels. They estimate the channel state information at the receiver in time domain using a PSO based algorithm during training phase....

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  • White Papers // Mar 2012

    Optimal Node Selection Using Estimated Data Accuracy Model in Wireless Sensor Networks

    One of the major task of wireless sensor network is to sense accurate data from the physical environment. Hence in this paper, the authors develop an estimated data accuracy model for randomly deployed sensor nodes which can sense more accurate data from the physical environment. They compare their results with...

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  • White Papers // Jan 2012

    Performance Modeling and Architecture Exploration of Network Processors

    In this paper, the authors propose a Petri net model for a commercial network processor (Intel IXP architecture) which is a multithreaded multiprocessor architecture. They consider and model three different applications viz., IPv4 forwarding, network address translation, and IP security running on IXP 2400/2850. A salient feature of the Petri...

    Provided By Indian Institute of Science

  • White Papers // Jan 2012

    Wireless Network-Coded Accumulate-Compute and Forward Two-Way Relaying

    The design of modulation schemes for the physical layer network-coded two way wireless relaying scenario is considered. It was observed by Koike-Akino et al. for the two way relaying scenario, that adaptively changing the network coding map used at the relay according to the channel conditions greatly reduces the impact...

    Provided By Indian Institute of Science

  • White Papers // Jan 2012

    State Dependent Attempt Rate Modeling of Single Cell IEEE 802.11 WLANs With Homogeneous Nodes and Poisson Arrivals

    Analytical models of IEEE 802.11-based WLANs are invariably based on approximations, such as the well-known mean-field approximations proposed by Bianchi for saturated nodes. In this paper, the authors provide a new approach for modeling the situation when the nodes are not saturated. They study a State Dependent Attempt Rate (SDAR)...

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  • White Papers // Dec 2011

    Optimal Deployment of Impromptu Wireless Sensor Networks

    The need for impromptu wireless networks arises in emergency situations where the team responding to the emergency, needs to deploy sensors (such as motion sensors, or even imaging sensors) and a wireless interconnection network, without any prior planning or knowledge of the terrain. In this paper, the authors consider a...

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  • White Papers // Dec 2011

    QoS Aware and Survivable Network Design for Planned Wireless Sensor Networks

    The authors study the problem of wireless sensor network design by deploying a minimum number of additional relay nodes (to minimize network cost) at a subset of given potential relay locations, in order to convey the data from already existing sensor nodes (hereafter called source nodes) to a Base Station,...

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  • White Papers // Nov 2011

    Computer Processing of Electroencephalographic Signals for Functional Connectivity Analysis of the Brain Using Graph Theoretic Techniques

    Computer processing of biomedical signals have gained a lot of importance because its extensive applications in healthcare. Extensive studies have been made on various aspects of bioengineering and in this paper, the authors consider its application to neuroscience one of the important area of study is on the functional connectivity...

    Provided By Indian Institute of Science