I've just joined the University of Pittsburgh School of Computing and Information as an assistant professor (Fall 2019). I'm looking for PhD, masters, and/or undergrad students interested in distributed systems and networks in general, and next-generation Internet services, resilient critical infrastructure, and resilient communities in particular. If you think the kind of work I do is interesting, feel free to send me an email!
I am also a partner at Spread Concepts LLC, an engineering firm in Savage, MD that works to bridge the gap between cutting-edge research and real-world needs.
I completed my PhD in the Department of Computer Science at Johns Hopkins University in September 2018. My thesis is titled "Timely, Reliable, and Cost-Effective Internet Transport Service using Structured Overlay Networks" and my advisor was Yair Amir. As a PhD student, I was a member of the Distributed Systems and Networks lab. I completed my Masters in Computer Science in May 2014 at Johns Hopkins and worked at LTN Global Communications before starting my PhD. I received my B.A. in Cognitive Science from Johns Hopkins in May 2012.
I am working toward supporting a new generation of Internet services using structured overlay networks. This broad vision is outlined in an ICDCS 2017 vision track paper that describes how services that require highly demanding combinations of latency, reliability, resilience, and processing can be realized using the structured overlay concept.
My most recent work focuses on services with extremely low latency requirements (e.g. remote manipulation). This video shows me interacting with a Phantom Omni haptic device over a wide-area network. The signal from each device is sent halfway across the US before being sent back to the other device, so the latency is as if one device is on the East coast and the other is on the West coast. You can hear this latency when I tap on the desk. My work in this area aims to enable such low-latency communication and interaction with high reliability.
To support such applications, we have developed new overlay dissemination protocols that send messages over a subgraph of an overlay topology (a dissemination graph) to provide the necessary timeliness and reliability. This includes work with Emily Wagner, Michael Dinitz, and Yair Amir on constructing dissemination graphs that provide a good tradeoff between reliability and cost, which was selected for the best paper award at ICDCS 2017.
Before starting my PhD, I gained exposure to global-scale overlay technologies in the commercial world at LTN Global Communications. LTN is a cloud service provider that operates global overlay networks, transporting live video for the TV and media industries.
PhD Thesis: Timely,
Reliable, and Cost-Effective Internet Transport Service using
Structured Overlay Networks
Spines 5.3: Overlay Network Platform
ICDCS 2017 (Vision Track): Structured Overlay Networks for a New Generation of Internet Services
ICDCS 2017: Timely, Reliable, and Cost-Effective Internet Transport Service using Dissemination Graphs
DSN 2015 Student Forum: Timely, Reliable, and Cost-effective Transport Service using Dissemination Graphs
I am interested in building dependable infrastructure, or networked systems that maintain correct operation and predictable performance, even in the presence of partial failures or compromises. I am currently working on applying intrusion-tolerant principles to create SCADA systems for the power grid that can continue to operate correctly and at their required levels of performance even when part of the system has been compromised by a sophisticated attacker. We have recently released version 1.0 of the Spire intrusion-tolerant SCADA system, which is designed to withstand malicious attacks at both the network level and the system level. Spire successfully withstood a red team attack conducted by Sandia National Laboratories at Pacific Northwest National Laboratory (PNNL) from March 27 to April 7, 2017 and was demonstrated in a test-deployment at the Hawaiian Electric Company from January 22 to February 2, 2018.
I am additionally interested in consistent state maintenance in the presence of failures, including approaches such as Paxos and Extended Virtual Synchrony, as well as resilient (including intrusion-tolerant) systems more generally.
ICDCS 2018 (Vision Track): Toward an Intrusion-Tolerant Power Grid: Challenges and Opportunities
DSN 2018: Network-Attack-Resilient Intrusion-Tolerant SCADA for the Power Grid
ICDCS 2016: Practical Intrusion-Tolerant Networks
Spire 1.0: Intrusion-Tolerant SCADA for the Power Grid
Prime 3.0: Intrusion-Tolerant Replication Engine
I developed a reliable, ordered multicast protocol based on a logical token ring that improves the state-of-the-art performance on 1-gigabit and 10-gigabit local area networks. The Accelerated Ring protocol circulates the token more quickly, reducing the impact of latency due to buffering and allowing for controlled parallelism in sending. I incorporated the Accelerated Ring protocol into the messaging protocol of the Spread Toolkit. A version of Spread that includes this protocol was released as an experimental version in July 2013, and the Accelerated Ring protocol is the toolkit's standard protocol for data center environments as of version 4.4.0.
ICDCS 2016: Fast
Total Ordering for Modern Data Centers
ICDCS 2015 Poster: Fast Total Ordering for Modern Data Centers
Masters Thesis: The Accelerated Ring Protocol: Ordered Multicast for Modern Data Centers