Ph.D., Computer Science
Department of Computer Science, Vanderbilt University, Nashville, TN.
Advisors: Janos Sztipanovits, Akos Ledeczi, Miklos Maroti
Dissertation: Spatiotemporal Coordination In Wireless Sensor Networks

M. S., Computer Science
("Magister" in Computer Science)
Comenius University, Bratislava, Slovakia.
Specialization: Mathematical Methods and Computer Graphics
Advisor: Martin Skoviera
Thesis: An Effective Algorithm to Determine the Maximal Genus of Signed Graphs

B. S., Computer Science
(State Exams in Mathematics and Computer Science)
Comenius University, Bratislava, Slovakia.

• Routing to a mobile sink
  • The Whirlpool Ad-hoc Routing Protocol (WARP) - a data collection protocol for mobile users with high reliability and low latency of data delivery. Techniques used in WARP include active detection of user mobility, speculative routing of data around the previous location of the user, and blurring the boundary between the control and data planes of routing protocols.
    
  • Predictive routing protocol - a routing protocol for when a node moves non-locally in the network connectivity graph, requiring global reconfiguration of the routing state. We proposed a novel data structure, the mobility graph, that encodes likely mobility patterns within the network and can be used to predict future location of mobile nodes. This enables routing protocols to reconfigure their state proactively and maintain uninterrupted data streams.
• Camera sensor networks - information rich images provide superior information over simpler sensors, but their interpretation is hard in resource constrained domains. Our multi-tier system combines camera sensors with more capable devices that provide sufficient bandwidth for delivering images to users. Following successful internet applications, which recommend music, images, and movies based on user feedback, the system encourages user collaboration in interpreting images.
• Indoor localization of moving objects using RF signals - we proposed a novel localization method that maps a short history of RF signal strengths of a mobile node to a 2D position. The method provides accurate localization without requiring the node to be stationary during the measurements.

• PinPtr - a sensor network based shooter localization system that analyzes acoustic signals of gunshots (shockwave and muzzle blast) to determine the location of the shooter and the trajectory of the bullet. Utilizing up to a hundred spatially distributed sensor nodes, PinPtr achieves superior fault tolerance and resilience to acoustic echoes. The system was demonstrated in realistic urban environments and achieved 1 meter accuracy in 3D.
• inTrack - a tracking system capable of localizing single moving object with better than 1 meter position accuracy using low-cost hardware. inTrack was used in a dirty bomb detection and localization system that tracked the movement of a guard carrying a radiation detector in real time.
• Radio-interferometric Positioning Service (RIPS) - a novel ranging and localization method for wireless sensor networks. The technique relies on a pair of nodes emitting radio waves simultaneously at slightly different frequencies. Measuring relative phase offsets of the resulting interference signal at two receivers, our Mica2 implementation yields an average localization error of 3 cm and a range of up to 160 meters.
• Time synchronization protocols:
  • Flooding Time-synchronization Protocol (FTSP) - a robust proactive time-synchronization service that offers microsecond precision on resource limited wireless platforms. FTSP was implemented on a number of platforms and became part of TinyOS2 core in 2008.
  • Routing Integrated Time-synchronization (RITS) - a reactive time synchronization protocol that establishes a common reference time base post facto. RITS provides high accuracy, having virtually no radio communication overhead.

• mTrack - a tracking system capable of monitoring positions of multiple (theoretically arbitrarily many) mobile objects. The system utilizes radio interference to measure Doppler frequency shifts of mobile objects and calculates velocity vectors of these objects.

• Master's thesis - I focused on the topological graph theory, specifically, on the orientation embeddings of unsigned graphs. I proved several new theorems that allowed me to develop an efficient algorithm to determine the maximum constrained genus of signed graphs.