Projects

- Partially Funded by the National Science Foundation (NSF). NSF NeTS: Small: Award # 1320694.

People

  Main Personnel:

• - Faculty: Ahmed Helmy (Principal Investigator and Main Supervisor)

• - Current Students:

  • - Babak Alipour, Ph.D. student (lead student researcher for integrated traffic-mobility analysis for pedestrians).

  • - Roozbeh Ketabi, Ph.D. student (lead student researcher for the vehicular mobility analysis and simulation).

  • - Mimonah Al-Qathrady, Ph.D. student (lead student researcher for the indoor mobility, encounter estimation and infection tracing).

  Other Contributors and Collaborators:

• - Current Collaborators:

  • - Jörg Ott, Professor and Chair of Connected Mobility, Technical University of Munich (TUM), Germany.

  • - Leonardo Tonetto, Ph.D. student, TUM - Aaron Ding, PostDoc, TUM - Ljubica Kaerkkaeinen, Ph.D. student, KTH

• - Previous Students and Collaborators:

  • - Khalid Almuzaini, KACST, Riyadh, KSA - Pan Hui, HKUST & U. Helsinki - Damien Fay, Bournemouth U. - Tamer ElBatt, Cairo U.

  • - Students: Gautam Thakur, ORNL, TN - Saeed Moghaddam, Apple Inc, - Mai ElSherief, UCSB.

Research Publications, Outcomes, and Data

• - Mobility Analysis & Modeling: (see also MobiLib, [More data and tools to be shared. Updates to be made soon!])

  1. B. Alipour, L. Tonetto, R. Ketabi, A. Ding, J. Ott, A. Helmy, "Flutes vs. Cellos: Analyzing Mobility-Traffic Correlations in Large WLAN Traces", IEEE INFOCOM, April 2018. (to appear) [Acceptance rate: 19%] [This study was driven by over 30TB of data].

  2. M. ElSherief, B. Alipour, M. Alqathrady, T. ElBatt, A. Zahran, A. Helmy, "A Novel Mathematical Framework for Similarity-based Opportunistic Social Networks", Pervasive and Mobile Computing (PMC) Journal – Elsevier, pp. 134 – 150, Vol. 42, December 2017.

  3. S. Moghaddam, A. Helmy, “Interest-based Mining and Modeling of Big Mobile Networks”, In proceedings of IEEE Big Data Service (IEEE International Conference on Big Data Computing Service and Applications), March/April 2015. [Acceptance rate: ~25%]

  4. M. ElSherief, T. ElBatt, A. Zahran, A. Helmy, "An Information-theoretic Model for Knowledge Sharing in Opportunistic Social Networks", In proceedings of the 8th IEEE International Conference on Social Computing and Networking (SocialCom), December 2015.

  5. S. Moghaddam, A. Helmy, "Interest-aware Implicit Multicast (iCast): Opportunistic Mobile Data Dissemination Without Per-group Management", In proceedings of ACM MobiCom MobiArch (Mobility in the Evolving Internet Architecture Workshop), Sept 2014.

• - Vehicular Mobility Analysis and Simulation:

  1. R. Ketabi, B. Alipour, A. Helmy, "En Route: Towards Vehicular Mobility Scenario Generation at Scale", In proceedings of the IEEE INFOCOM – SmartCity workshop, May 2017. (Avg. review score: 5/5).

  2. R. Ketabi, B. Alipour, A. Helmy, "Poster Abstract: En Route: Towards Trace-based Simulation of Vehicular Mobility", IEEE INFOCOM, May 2017. (Winner of The Best Poster Award).

  3. G. Thakur, P. Hui, A. Helmy, "Evidence of Long Range Dependence and Self-similarity in Urban Traffic Systems", In proceedings of the International Conference on Advances in Geographic Information Systems (ACM SIGSPATIAL), November 2015. [Acceptance rate: ~18%]

  4. D. Fay, G. Thakur, P. Hui, A. Helmy, "Knowledge Discovery and Causality in Urban City Traffic: A study using Planet Scale Vehicular Imagery Data", In proceedings of ACM SIGSPATIAL IWCTS (Int'l workshop on Computational Transportation Science), November 2013. (Winner of The Best Paper Award) [Acceptance rate: 21%].

• - Indoor Mobility & Encounter Analysis, and Smart Hospital Infection Tracing:

  1. M. Al-Qathrady, A. Helmy, "Improving BLE Distance Estimation and Classification using TX power and Machine Learning: A Comparative Analysis", In proceedings of the ACM MSWiM (International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems), November 2017.

  2. M. Al-Qathrady, A. Helmy, "Location-Centric Flow Flux for Improved Indoor Mobility Models", In proceedings of the IEEE INFOCOM – SmartCity workshop, May 2017.

  3. M. Al-Qathrady, A. Helmy, K. Almuzaini, "Infection Tracing in Smart Hospitals", Book chapter 16 in the book “The Internet of Things: Foundation for Smart City, eHealth and Ubiquitous Computing”, Eds. Armentano, Bhadoria, Chatterjee, Deka, by CRC, ISBN 9781498789028, 2017.

  4. M. Al-Qathrady, A. Helmy, “Poster Abstract: Location-Centric Flow Flux for Improved Indoor Mobility Models”, IEEE INFOCOM, May 2017.

  5. M. Al-Qathrady, A. Helmy, K. Almuzaini, "Infection Tracing in Smart Hospitals", In proceedings of the IEEE WiMob conference - e-Health Pervasive Wireless Applications and Services workshop (eHPWAS), Oct. 2016.

Privacy: No private information is contained in the traces used. Trace acquisition adhered to the IRB approval/exemption rules, and proper permissions were granted when needed.

- Funded by NSF and Cisco.

- Please see publications on 'profile-cast', 'mining behavior', and 'co-clustering' for more details.

- Funded by NSF (CAREER), Intel (2 research & 1 equipment awards), Nortel, Siemens, and HP equipment awards.

• Mobility Modeling & Analysis: (see also MobiLib, TVC tool & IMPORTANT tool)

  • 1. TVC: W. Hsu, T. Spyropoulos, K. Psounis, A. Helmy, "Modeling Time-variant User Mobility in Wireless Mobile Networks", IEEE INFOCOM, May '07.

    2. PATHS: F. Bai, N. Sadagopan, B. Krishnamachari, A. Helmy, "Modeling Path Duration Distributions in MANETs and their Impact on Routing Performance", IEEE Journal on Selected Areas of Communications (JSAC), Vol. 22, No. 7, pp. 1357-1373, Sept '04. [Earlier in ACM MobiHoc '03 (15% Acceptance)] (slides)

    3. F. Bai, N. Sadagopan, A. Helmy, "The IMPORTANT Framework for Analyzing the Impact of Mobility on Performance of Routing for Ad Hoc Networks", AdHoc Networks Journal - Elsevier, Vol. 1, Issue 4, pp. 383-403, November 2003. [Earlier version in IEEE INFOCOM '03 (20% Acceptance)]

    4. Trace-based Mobility (MobiLib: The Mobility Trace Library): [The IMPACT study: Investigation of Mobile-user Patterns Across Campuses using WLAN Trace Analysis]

       • W. Hsu, D. Dutta, A. Helmy, "Mining Behavioral Groups in Large Wireless LANs", ACM MobiCom, pp. 338-341 (short paper), Sept. 2007. [In the top 11% of 233 submissions.] (Journal version in submission). [Extended version as technical report].

       • W. Hsu, A. Helmy, "On Nodal Encounter Patterns in Wireless LAN Traces", IEEE Int'l Workshop on Wireless Network Measurement (WiNMee), April 2006.

       • W. Hsu, A. Helmy, "On Modeling User Associations in Wireless LAN Traces on University Campuses", IEEE Int'l Workshop on Wireless Network Measurement (WiNMee), April 2006.

       • W. Hsu, K. Merchant, H. Shu, C. Hsu, A. Helmy, "Weighted Waypoint Mobility Model and its Impact on Ad Hoc Networks", ACM Mobile Computer Communications Review (MC2R) (among the best MobiCom '04 posters), Jan 2005.

    5. F. Bai, A. Helmy, "Impact of Mobility on Mobility-Assisted Information Diffusion (MAID) Protocols", IEEE SECON '07

• Robust Geographic Protocols and Services:

  • 1. Optimal Geographic Routing: K. Seada, M. Zuniga, A. Helmy, B. Krishnamachari, "Energy-Efficient Forwarding Strategies for Geographic Routing in Lossy Wireless Sensor Networks", ACM Conference on Embedded Networked Sensor Systems (SenSys) '04 (14.5% Acceptance) [ Journal version published in ACM Trans. on Sensor Networks (ToSN) '08]

    2. Effect of Inaccuracy on Face Routing: Karim Seada, Ahmed Helmy, Ramesh Govindan, "On the Effect of Localization Errors on Geographic Face Routing in Sensor Networks", IEEE/ACM Int'l Symp on Information Processing in Sensor Networks (IPSN), Apr '04 [Journal in Ad Hoc Networks Journal -ElSevier '07]

    3. Robust Geocast: K. Seada, A. Helmy, "Efficient and Robust Geocasting Protocols for Sensor Networks", Journal of Computer Communications - Elsevier, Jan '06. [Earlier in IEEE WCNC 04]

    4. K. Seada, A. Helmy, " Rendezvous Regions: A Scalable Architecture for Service Location and Data-Centric Storage in Large-Scale Wireless Networks", IEEE/ACM IPDPS Workshop on Algorithms for Wireless, Mobile, Ad Hoc & Sensor Networks (WMAN), April 04. [Journal version to appear in Wireless Comm. & Mobile Computing in 2009]

    5. C. Li, W. Hsu, B. Krishnamachari, A. Helmy, "A Local Metric for Geographic Routing with Power Control in Wireless Networks", IEEE Conference on Sensor and Ad Hoc Communications and Networks (SECON), September 2005 [Acceptance rate: 27%]

• Security in Ad Hoc and Sensor Networks:

  • 1. S. Tanachaiwiwat, A. Helmy, "Encounter-based Worms: Analysis and Defense", Ad Hoc Networks Journal - Elsevier. Accepted Feb 2009.

    2. Y. Kim, A. Helmy, "CATCH: A Protocol Framework for Cross-layer Attacker Traceback in Mobile Multi-Hop Networks", Ad Hoc Networks Journal - Elsevier. Accepted July 2009. To appear.

    3. Y. Kim, A. Helmy, "SWAT: Small World-based Attacker Traceback in Ad-hoc Networks", IEEE/ACM Mobiquitous Conference, Jul 2005.

• TCP over Ad Hoc:

  • K. Nahm, A. Helmy, C.-C. Kuo, "TCP over Multihop 802.11 Networks: Issues and Performance Enhancement", ACM MobiHoc, May 2005 (acceptance rate 14%) [Journal version published in IEEE Transactions on Mobile Computing (TMC), pp. 458 - 469, Vol. 7, Issue 4, April 2008.]

- Funded by NSF.

• - Efficient Queries and Resource Discovery in Sensor Networks:

  1. Multi-variable Query Resolution (ACQUIRE): N. Sadagopan, B. Krishnamachari, A. Helmy, "Active Query Forwarding in Sensor Networks (ACQUIRE)", AdHoc Networks Journal - Elsevier, Vol.3, No.1, pp.91-113, January 2005 [Earlier version in IEEE ICC SNPA workshop, May '03]

  2. A. Helmy, "Small Worlds in Wireless Networks", IEEE Communications Letters, pp. 490-492, Vol. 7, No. 10, October 2003.

  3. A. Helmy, " Mobility-Assisted Resolution of Queries in Large-Scale Mobile Sensor Networks (MARQ)", Computer Networks Journal - Elsevier (Special Issue on Wireless Sensor Networks), Vol. 43, Issue 4, pp. 437-458, Nov 2003.

  4. A. Helmy, "Efficient Resource Discovery in Wireless AdHoc Networks: Contacts Do Help", Book chapter in "Resource Management in Wireless Networking", Springer, ISBN: 0-387-23807-7, Vol. 16, 2005. [Earlier Journal Version in IEEE Transactions on Vehicular Technology, Jan '05]

• - Gradient-based Routing:

  1. J. Faruque, K. Psounis, A. Helmy, "Analysis of Gradient-based Routing Protocols in Sensor Networks", IEEE/ACM Int'l Conference on Distributed Computing in Sensor Systems (DCOSS), June 2005.

  2. RUGGED: J. Faruque, A. Helmy, "RUGGED: RoUting on finGerprint Gradients in sEnsor Networks", IEEE Int'l Conf. on Pervasive Services (ICPS), Jul 04. Also, among the best posters from ACM MOBICOM 2003 [Poster, Abstract (.ps)]

- Funded by Nortel & USC.

1. A. Helmy, M. Jaseemuddin, G. Bhaskara, "Multicast-based Mobility: A Novel Architecture for Efficient Micro-Mobility", IEEE Journal on Selected Areas in Communications (JSAC), Special Issue on All-IP Wireless Networks, Vol. 22, No. 4, pp. 677-690, May 2004.

2. A. Helmy, "A Multicast-based Protocol for IP Mobility Support", ACM SIGCOMM Int'l Workshop on Networked Group Communication (NGC), November 2000 [ ppt] [Here is a library of topologies used for the simulations of M&M (NGC), in a format compatible with the network simulator (NS-2)].

3. F. Bai, G. Bhaskara, A. Helmy, "Building the Blocks of Protocol Design and Analysis - Challenges and Lessons Learned from Case Studies on Mobile Ad hoc Routing and Micro-Mobility Protocols", ACM Computer Communications Review (CCR), Special issue on Science of Networking Design, Volume 34, Number 3, pp. 57 - 69, July 2004. [Acceptance rate: 15% of 40 submissions]

4. G. Bhaskara, A. Helmy, "TCP over Micro Mobility Protocols: A Systematic Ripple Effect Analysis", IEEE Vehicular Technology Conf (VTC), Sept '04

5. A. Helmy, "State Analysis and Aggregation Study for Multicast-based Micro Mobility", IEEE ICC, Vol. 5, pp. 3301-3306, May 2002.

- Funded by NSF, NASA, and DARPA.

1. S. Begum, A. Helmy, S. Gupta, "Modeling the Interactions Between MAC and Higher Layers: A Systematic Approach to Generate High Level Scenarios from MAC Level Scenarios", ACM Transactions on Modeling and Computer Simulation (TOMACS). Accepted, to appear in Spring 2010.

2. S. Begum, A. Helmy, S. Gupta, "Modeling and Test Generation for Worst-Case Performance Evaluation of MAC Protocols for Wireless Ad Hoc Networks", IEEE Int'l Symposium on Modelling, Analysis and Simulation of Computer and Telecommunication Systems (MASCOTS), full presentation, Sept. 2009.

3. S. Begum, S. Gupta, A. Helmy, "Performance Analysis of Wireless MAC Protocols using a Search-based Framework", 15th IEEE Int'l Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems (MASCOTS), Oct. 2007.

4. S. Ebrahimi, A. Helmy, S. Gupta, "TCP vs. TCP: a Systematic Study of Adverse Impact of Short-lived TCP Flows on Long-lived TCP Flows", IEEE INFOCOM, March 2005. [Earlier version as ACM SIGCOMM poster, August 2004. (Poster (pdf))]

5. K. Seada, A. Helmy, S. Gupta, "A Framework for Systematic Evaluation of Multicast Congestion Control Protocols", IEEE Journal on Selected Areas in Communications (JSAC), Special issue on Protocol Design and Testing, Vol. 22, No. 10, Dec 2004. [Earlier version at IEEE GLOBECOM, Nov '02]

6. A. Helmy, S. Gupta, D. Estrin, 'The STRESS Method for Boundary-point Performance Analysis of End-to-end Multicast Timer-Suppression Mechanisms', IEEE/ACM Transactions on Networking (ToN), Vol. 12, No. 1, pp. 44-58, February 2004. [Earlier version in FORTE/PSTV Oct 2000.]

7. F. Bai, G. Bhaskara, A. Helmy, "Building the Blocks of Protocol Design and Analysis - Challenges and Lessons Learned from Case Studies on Mobile Ad hoc Routing and Micro-Mobility Protocols", ACM Computer Communications Review (CCR), Special issue on Science of Networking Design, Volume 34, Number 3, pp. 57 - 69, July 2004. [Acceptance rate: 15% of 40 submissions].

8. A. Helmy, D. Estrin, S. Gupta, "Systematic Testing of Multicast Routing Protocols: Analysis of Forward and Backward Search Techniques", The 9th International Conference on Computer Communications and Networks (IEEE ICCCN 2000), pp. 590-597, October 2000. Abstract.

9. S. Begum, M. Sharma, A. Helmy, S. Gupta, "Systematic Testing of Protocol Robustness: Case Studies on Mobile IP and MARS", Proceedings of the 25th annual IEEE conference on Local Computer Networks (LCN), pp. 369-380, Florida, November 2000. Abstract

10. A. Helmy, D. Estrin, S. Gupta, "Fault-oriented Test Generation for Multicast Routing Protocol Design", Proceedings of Formal Description Techniques & Protocol Specification, Testing, and Verification (FORTE/PSTV), IFIP, Kluwer Academic Publication, Paris, France, p. 93-109, November 1998.

1. A. Das, D. Dutta, A. Helmy, A. Goel, J. Heidemann, "Low State Fairness: Lower Bounds and Practical Enforcement", IEEE INFOCOM, March 2005.

2. A. Das, D. Dutta, A. Helmy, "A Low-state Packet Marking Framework for Approximate Fair Bandwidth Allocation", IEEE Communications Letters, Vol. 8, No. 9, pp. 588-590, Sept 2004.

3. A. Das, D. Dutta, A. Helmy, "Fair Stateless Aggregate Marking using Active Queue Management Techniques", IEEE International Conference on Management of Multimedia Networks and Services (MMNS), pp. 211-223, October 2002. (Best Paper Award).

1. L. Breslau, D. Estrin, K. Fall, S. Floyd, J. Heidemann, A. Helmy, P. Huang, S. McCanne, K. Varadhan, Y. Xu, H. Yu, "Advances in Network Simulation", IEEE Computer, vol. 33, No. 5, p. 59-67, May 2000.

2. A. Helmy, D. Estrin, "Simulation-based `STRESS' Testing Case Study: A Multicast Routing Protocol", IEEE Sixth International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems (MASCOTS), Montreal, Canada, July 1998.

- Partially funded by Silicon Graphics Inc., Sun Microsystems, and Cisco, among others.

1. D. Estrin, M. Handley, A. Helmy, P. Huang, D. Thaler, " A Dynamic Bootstrap Mechanism for Rendezvous-based Multicast Routing", Proceedings of IEEE INFOCOM '99, New York, Vol. 3, pp. 1090-1098, March 1999.

2. D. Estrin, D. Farinacci, A. Helmy, D. Thaler, S. Deering, V. Jacobson, M. Handley, C. Liu, P. Sharma, L. Wei, "Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification, Version 2", RFC 2362/2117 of the Internet Engineering Task Force (IETF), Inter-Domain Multicast Routing (IDMR), June 1998. [RFC2362]

3. D. Estrin, D. Farinacci, A. Helmy, D. Thaler, S. Deering, V. Jacobson, M. Handley, C. Liu, P. Sharma, L. Wei, "Protocol Independent Multicast (PIM): Motivation and Architecture", Proposed RFC of the IETF/IDMR, October 1996. [.ps]

4. D. Estrin, D. Farinacci, A. Helmy, V. Jacobson, L. Wei, "Protocol Independent Multicast - Dense Mode (PIM-DM): Protocol Specification", Proposed RFC of the IETF/IDMR, September 1996.