Runtime Dynamic Path Identification for Preventing Ddos Attacks 1Shaik Zahanath Ali, 2Shobini.B and 3G.Shiva Krishna
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Estimating Network Loss Rates Using Active Tomography
Estimating Network Loss Rates Using Active Tomography Bowei XI, George MICHAILIDIS, and Vijayan N. NAIR Active network tomography refers to an interesting class of large-scale inverse problems that arise in estimating the quality of service parameters of computer and communications networks. This article focuses on estimation of loss rates of the internal links of a network using end-to-end measurements of nodes located on the periphery. A class of flexible experiments for actively probing the network is introduced, and conditions under which all of the link-level information is estimable are obtained. Maximum likelihood estimation using the EM algorithm, the structure of the algorithm, and the properties of the maximum likelihood estimators are investigated. This includes simulation studies using the ns (network simulator) to obtain realistic network traffic. The optimal design of probing experiments is also studied. Finally, application of the results to network monitoring is briefly illustrated. KEY WORDS: EM algorithm; Inference on graphs; Network modeling; Network monitoring; Network tomography; Probing experiments. 1. INTRODUCTION parameters requires access to the internal links and routers. But the lack of centralized control of modern networks means that The term “network tomography” was introduced by Vardi Internet service providers typically do not have access to all the (1996) to characterize a certain class of inverse problems nodes of interest, making collection of detailed QoS informa- in computer and communication networks. The goal here, tion at the individual router/link level difficult. Active tomogra- as in medical tomography problems, is to recover higher- phy provides an alternative approach through the use of active dimensional network information from lower-dimensional data. -
Georgios B. Giannakis, DTC Director ECE, Mcknight Presidential Chair (Last Update on 09/08/2021)
CV highlights - Georgios B. Giannakis, DTC Director ECE, McKnight Presidential Chair (last update on 09/08/2021) I. Leadership and administrative roles 1) Digital Technology Center (DTC) Director: College-wide, cross-disciplinary research center, University of Minnesota (2008-2021) a) Managed 12 administrative staff; space; seed funds; and endowed chairs; b) Spearheaded externally sponsored projects; facilitated resource allocation; and coordinated summer internships, industry partnerships, fellowships, and seminar series; c) Doubled DTC researchers (100 graduate students; 20+ postdoctoral fellows; 30+ research visitors; and 50 affiliated faculty) d) Increased by a factor of five publications, patents, proposals, and funding ($30M/10yrs) e) Broadened research spectrum to include Data Science, Network Science, Renewables, Grid, Environmental, and Health Informatics; f) Expanded cross-departmental/college partnerships to include the College of Liberal Arts; School of Public Affairs; Business School; Chemical Engineering, and Neuroscience; g) Enhanced community outreach (Robotics Tech Camp; Lab tours for middle and high school students; and Summer school on bioinformatics) 2) Major posts in professional society: Institute of Electrical and Electronic Engineers (IEEE) IEEE Signal Processing and Communication Societies (SPS and ComSoc) a) IEEE Fellow and IEEE Proceedings Committee Member b) Board of Governors member; and Editor-in-Chief (SPS) c) Chair of Steering and Technical Committees (SPS and ComSoc) d) General Conference Chair, including the IEEE Data Science Workshop, 2019 3) Multi-university projects and proposals a) Army Research Laboratory, Collaborative Technology Alliance; Technical Area Lead b) Medium- and large-size proposals to the National Science Foundation, NIH, DoD 4) Board of Regents elected member (University of Patras, Greece, 2014-2017) 5) Hellenic Quality Assurance and Accreditation Agency, Ministry of Education, Greece 6) Research group: 12 Ph.D. -
Practical Network Tomography
Practical Network Tomography THÈSE NO 5332 (2012) PRÉSENTÉE LE 27 AOÛT 2012 À LA FACULTÉ INFORMATIQUE ET COMMUNICATIONS LABORATOIRE POUR LES COMMUNICATIONS INFORMATIQUES ET LEURS APPLICATIONS 3 Laboratoire D'ARCHITECTURE DES RÉSEAUX PROGRAMME DOCTORAL EN INFORMATIQUE, COMMUNICATIONS ET INFORMATION ÉCOLE POLYTECHNIQUE FÉDÉRALE DE LAUSANNE POUR L'OBTENTION DU GRADE DE DOCTEUR ÈS SCIENCES PAR Denisa Gabriela Ghiţă acceptée sur proposition du jury: Prof. E. Telatar, président du jury Prof. P. Thiran, Prof. A. Argyraki, directeurs de thèse Prof. A. Krishnamurthy, rapporteur Prof. J.-Y. Le Boudec, rapporteur Dr W. Willinger, rapporteur Suisse 2012 ii Bunicilor mei... iv Abstract In this thesis, we investigate methods for the practical and accurate localization of Internet performance problems. The methods we propose belong to the field of network loss tomography, that is, they infer the loss characteristics of links from end-to-end measurements. The existing versions of the problem of network loss tomography are ill-posed, hence, tomographic algorithms that attempt to solve them resort to making various assumptions, and as these assumptions do not usually hold in practice, the information provided by the algorithms might be inaccurate. We argue, therefore, for tomographic algorithms that work under weak, realistic assumptions. We first propose an algorithm that infers the loss rates of network links from end-to-end measurements. Inspired by previous work, we design an algorithm that gains initial information about the network by computing the variances of links’ loss rates and by using these variances as an indication of the congestion level of links, i.e., the more congested the link, the higher the variance of its loss rate. -
Delay and Traffic Rate Estimation in Network Tomography
DELAY AND TRAFFIC RATE ESTIMATION IN NETWORK TOMOGRAPHY by Neshat Etemadi Rad A Dissertation Submitted to the Graduate Faculty of George Mason University In Partial fulfillment of The Requirements for the Degree of Doctor of Philosophy Electrical and Computer Engineering Committee: Dr. Yariv Ephraim, Co-director Dr. Brian L. Mark, Co-director Dr. Jill K. Nelson, Committee Member Dr. James Gentle, Committee Member Dr. Monson H. Hayes, Department Chair Dr. Kenneth S. Ball, Dean, Volgenau School of Information Technology and Engineering Date: Fall Semester 2015 George Mason University Fairfax, VA Delay and Traffic Rate Estimation in Network Tomography A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at George Mason University By Neshat Etemadi Rad Master of Science Sharif University of Technology, Tehran, Iran, 2010 Bachelor of Science Amirkabir University of Technology, Tehran, Iran, 2008 Co-director: Dr. Yariv Ephraim, Professor Co-director: Dr. Brian L. Mark, Professor Department of Electrical and Computer Engineering Fall Semester 2015 George Mason University Fairfax, VA Copyright c 2015 by Neshat Etemadi Rad All Rights Reserved ii Dedication To my parents, Avisa and Hamid, for without their early inspiration and coaching, none of this would have happened. To the love of my life, Abbas, for without his support and enthusiasm, none of this would have been accomplished. iii Acknowledgments I would like to thank my dissertation advisors, Professor Yariv Ephraim and Professor Brian L. Mark, for being supportive and patient throughout my PhD research at George Ma- son University. I am very grateful to them for their in-depth technical knowledge, guidance and insightful discussions.