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Sparsity of weighted networks: Measures and applications

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arXiv 2020年

作者： Goswami, Swati Das, Asit K. Nandy, Subhas C. Department of Computer Science and Technology Indian Institute of Engineering Science and Technology Shibpur Howrah711103 India Advanced Computing and Microelectronics Unit Indian Statistical Institute Kolkata700108 India

A majority of real life networks are weighted and sparse. The present article aims at characterization of weighted networks based on sparsity, as a measure of inherent diversity, of different network parameters. It utilizes sparsity index defined on ordered degree sequence of simple networks and derives further properties of this index. The range of possible values of sparsity index of any connected network, with edge-count in specific intervals, is worked out analytically in terms of node-count;a pattern is uncovered in corresponding degree sequences to produce highest sparsities. Given the edge-weight frequency distribution of a network, we have formulated an expression of the sparsity index of edge-weights. Its properties are analyzed under different distributions of edge-weights. For example, the upper and lower bounds of sparsity index of edge-weights of a network, having all distinct edge-weights, is determined in terms of its node-count and edge density. The article highlights that this summary index with low computational cost, computed on different network parameters, is useful to reveal different structural and organizational aspects of networks for performing analysis. An application of this index has been demonstrated through overlapping community detection of networks. The results validated on artificial and real-world networks show its efficacy. Copyright © 2020, The Authors. All rights reserved.

关键词： Population dynamics

Network-Assisted D2D Relay Selection Under the Presence of Dynamic Obstacles

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Network-Assisted D2D Relay Selection Under the Presence of D...

Conference on Local Computer Networks (LCN)

作者： Durgesh Singh Sasthi C. Ghosh Advanced Computing & Microelectronics Unit Indian Statistical Institute Kolkata India

Millimeter wave (mmWave) channels in device to device (D2D) communication are susceptible to blockages in spite of using directional beams from multi-input multi-output (MIMO) antennas to compensate for high propagation loss. This motivates one to look for the presence of obstacles while forming D2D links among user equipments (UEs) which are in motion. In D2D communication, moving UEs also act as relays to forward data from one UE to another which introduces the problem of relay selection. The problem becomes more challenging when the obstacles are also in motion (dynamic obstacles) along with the moving UEs. First we have developed a probabilistic model for relay selection which considers both moving UEs and dynamic obstacles. Then we have analyzed the probability of dynamic obstacles blocking a link in 3D Euclidean space by exploiting the information from MIMO radar connected to the base station. Finally, using this information, we have developed unique strategies based on simple geometry to find the best relay which maximizes the expected data rate. Through simulations we have shown that our proposed strategy gives a significant improvement in packet loss due to mobility of nodes and dynamic obstacles in a mmWave channel over the traditional approaches which do not consider dynamic obstacle's presence.

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$Q$-learning Based Network Selection Mechanism for CRNs with Secrecy Provisioning

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$Q$-learning Based Network Selection Mechanism for CRNs with...

IEEE International Symposium on Network computing and Applications

作者： Shankar K. Ghosh Sasthi C. Ghosh Advanced Computing & Microelectronics Unit Indian Statistical Institute Kolkata India

In near future, the spectrum resources shared by primary networks to spectrum pools are likely to use unlicensed band because of its increasing popularity. Due to the open access nature, in unlicensed band communication, eavesdroppers are capable of overhearing the traffic channels. This may lead to significant throughput degradation. Existing network selection mechanisms for cognitive radio networks (CRNs) do not consider this security threat adequately. In this work, we first propose a Q-learning based throughput estimation mechanism considering the possibility of throughput degradation caused by eavesdroppers. Then, based on estimated throughput values, we formulate the network selection problem in orthogonal frequency division multiple access (OFDMA) based CRNs as an integer linear program (ILP). Next, based on the ILP formulation, we propose a greedy algorithm for network selections in OFDMA based CRNs. Finally, performance of our proposed network selection mechanism has been compared with existing approaches through system level simulations.

关键词： Nickel Throughput Interference Security Base stations Degradation Resource management

Network-assisted D2D relay selection under the presence of dynamic obstacles

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arXiv 2019年

作者： Singh, Durgesh Ghosh, Sasthi C. Advanced Computing & Microelectronics Unit Indian Statistical Institute Kolkata700108 India

—Millimeter wave (mmWave) channels in device to device (D2D) communication are susceptible to blockages in spite of using directional beams from multi-input multi-output (MIMO) antennas to compensate for high propagation loss. This motivates one to look for the presence of obstacles while forming D2D links among user equipments (UEs) which are in motion. In D2D communication, moving UEs also act as relays to forward data from one UE to another which introduces the problem of relay selection. The problem becomes more challenging when the obstacles are also in motion (dynamic obstacles) along with the moving UEs. First we have developed a probabilistic model for relay selection which considers both moving UEs and dynamic obstacles. Then we have analyzed the probability of dynamic obstacles blocking a link in 3D Euclidean space by exploiting the information from MIMO radar connected to the base station. Finally, using this information, we have developed unique strategies based on simple geometry to find the best relay which maximizes the expected data rate. Through simulations we have shown that our proposed strategy gives a significant improvement in packet loss due to mobility of nodes and dynamic obstacles in a mmWave channel over traditional approaches which do not consider dynamic obstacle’s presence. Copyright © 2019, The Authors. All rights reserved.

关键词： 5G mobile communication systems

Web Service Selection with Correlations: A Feature-Based Abstraction Refinement Approach

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Web Service Selection with Correlations: A Feature-Based Abs...

IEEE International Conference on Service-Oriented computing and Applications (SOCA)

作者： Kaustabha Ray Ansuman Banerjee Swarup K. Mohalik Advanced Computing and Microelectronics Unit Indian Statistical Institute Ericsson Research Bangalore India

In this paper, we address the web service selection problem for linear workflows. Given a linear workflow specifying a set of ordered tasks and a set of candidate services providing different features for each task, the selection problem deals with the objective of selecting the most eligible service for each task, given the ordering specified. A number of approaches to solving the selection problem have been proposed in literature. With web services growing at an incredible pace, service selection at the Internet scale has resurfaced as a problem of recent research interest. In this work, we present our approach to the selection problem using an abstraction refinement technique to address the scalability limitations of contemporary approaches. Experiments on web service benchmarks show that our approach can add substantial performance benefits in terms of space when compared to an approach without our optimization.

关键词： Task analysis Web services Correlation Scalability Proposals Silicon compounds

How Successful is a Lockdown During a Pandemic?

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How Successful is a Lockdown During a Pandemic?

IEEE India Conference (INDICON)

作者： Anwesh Kabiraj Debojyoti Pal Pushan Bhattacherjee Kingshuk Chatterjee Ritajit Majumdar Debayan Ganguly Information Technology Government college of Engineering and Leather Technology Kolkata India Electrical Engineering Heritage Institute of Technology Kolkata India Computer Science & Engineering Government College of Engineering and Ceramic Technology Kolkata India Advanced Computing & Microelectronics Unit Indian Statistical Institute Kolkata India

ISBN: (数字)9781728169163

ISBN: (纸本)9781728169170

Social distancing, leading to lockdown, has been followed as a measure to restrict the spread of COVID-19 infection in almost every country. In this paper, we study the impact of the united States of America's lockdown measures during this pandemic in restricting the spread of infection. We have split the lockdown into two types - hard lockdown and soft lockdown. A hard lockdown is defined as the period when only essential services are provided. On the other hand, in the soft lockdown period, non-essential services are allowed, but with prevailing social distancing measures. Our findings suggest that a properly implemented Hard Lockdown followed by a soft Lockdown is indeed effective in reducing the reproduction number (R 0 ). Although R 0 increases during the soft lockdown, the rate of increase is restricted if the hard lockdown was implemented favorably. As exceptions to this general trend, we have observed that in Washington state Hard Lockdown has failed to reduce R 0 , and Vermont's soft lockdown implementation was successful in controlling the increase in R 0 post-Hard Lockdown.

关键词： COVID-19 Pandemics Conferences Human factors Market research Social factors Testing

Distributed relay selection in presence of dynamic obstacles in millimeter wave D2D communication

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arXiv 2019年

作者： Singh, Durgesh Chattopadhyay, Arpan Ghosh, Sasthi C. Advanced Computing and Microelectronics Unit Indian Statistical Institute Kolkata700108 India Department of Electrical Engineering Indian Institute of Technology Delhi

Millimeter wave (mmWave) device to device (D2D) communication is highly susceptible to obstacles due to severe penetration losses and requires almost a line of sight (LOS) communication path. D2D channel condition is local to devices/user equipments (UEs) and hence is not directly visible to the base station (BS). Thus quality of the D2D channel needs to be propagated to BS by UEs which may incur some delay. Hence the solution provided by BS to UEs using this gathered channel information might become less useful to establish communication due to moving obstacles. These types of obstacles might not be known in advance and hence may cause unpredictable fluctuations to the D2D channel quality. Hence we seek to learn the D2D channels using the finite horizon partially observable Markov decision process (POMDP) framework to model the uncertainty in such kind of network environments with dynamic obstacles. The objective is to minimize delay when channel quality deteriorates, by making UEs choose locally the best possible decision between i) to continue on the current relay link on which communication is taking place or ii) to switch to another good relay by exploring other possible UEs in its locality. We derive an optimal threshold policy which tells the UE to take appropriate decision locally. Later, we give a simplified and easy to implement stationary threshold policy which counts the number of successive acknowledgement failures, based on which UE make appropriate decision locally. Through extensive simulation, we demonstrate that our approach outperforms recent algorithms. Copyright © 2019, The Authors. All rights reserved.

关键词： Millimeter waves

Misinformation Containment in OSNs leveraging Community Structure

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Misinformation Containment in OSNs leveraging Community Stru...

IEEE International Conference on Awareness Science and Technology

作者： Arnab Kumar Ghoshal Nabanita Das Soham Das Department of Computer Science Asutosh College Kolkata India Advanced Computing and Microelectronics Unit Indian Statistical Institute Kolkata India Microsoft Corporation Redmond U.S.A

With the emergence of Online Social Networks (OSNs) as a major platform of communication, its abuse to spread misinformation has become a major threat to our society. In this paper, we study the misinformation containment problem in OSN. Given a snapshot of the OSN with a set of misinformed nodes, and a budget in terms of maximum number of seed nodes, the problem is to select the seed nodes, referred here as the beacon nodes, to plant the correct information, to minimize and eventually eradicate the misinformation at the earliest. We leverage the community structure of the OSN to select the beacon nodes, prioritizing the Community Boundary Nodes. To the best of our knowledge, this is the first work to exploit the topology of the OSN to combat misinformation spread. A modified form of Independent Cascade Model is followed to study the adversarial propagation of both misinformation and the correct information. Simulation on real data set shows that the proposed algorithm outperforms earlier algorithm significantly in terms of maximum (average) infected time and the point of decline.

关键词： Probabilistic logic Measurement Topology Sociology Statistics Twitter

Surface Code Design for Asymmetric Error Channels

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arXiv 2021年

作者： Azad, Utkarsh Lipińska, Aleksandra Mahato, Shilpa Sachdeva, Rijul Bhoumik, Debasmita Majumdar, Ritajit Center for Computational Natural Sciences and Bioinformatics International Institute of Information Technology Hyderabad India Center for Quantum Science and Technology International Institute of Information Technology Hyderabad India Xanadu TorontoONM5G 2C8 Canada Faculty of Mathematics and Computer Science Jagiellonian University Kraków Poland Department of Physics Indian Institute of Technology Dhanbad India Jülich Supercomputing Center Forschungszentrum Jülich Germany RWTH Aachen University Germany Advanced Computing & Microelectronics Unit Indian Statistical Institute Kolkata India

Surface codes are quantum error correcting codes typically defined on 2D array of qubits. In this paper, a [dx,dz] surface code design is being introduced, where dx(dz) represents the distance of the code for bit (phase) error correction, motivated by the fact that the severity of bit flip and phase flip errors in the physical quantum system is asymmetric. We present pseudo-threshold and threshold values for the proposed surface code design for asymmetric error channels in the presence of various degrees of asymmetry of Pauli Xˆ, Ŷ, and Ẑ errors in a depolarization channel. We demonstrate that compared to symmetric surface codes, our asymmetric surface codes can provide almost double the pseudo-threshold rates while requiring less than half the number of physical qubits in the presence of increasing asymmetry in the error channel. Our results show that for low degree of asymmetry, it is advantageous to increase dx along with dz. However, as the asymmetry of the channel increases, higher pseudo-threshold is obtained with increasing dz when dx is kept constant at a low value. Additionally, we also show that the advantage in the pseudo-threshold rates begins to saturate for any possible degree of asymmetry in the error channel as the surface code asymmetry is continued to increase. © 2021, CC BY-NC-ND.

关键词： Error correction