Research Projects

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    Performance Oriented Congestion Control

    Dramatically higher performance data delivery with a flexible transport architecture. This work is awarded Internet2 Innovative Application Award under the old name of BBCC

    The TCP family has failed to achieve consistent high performance in face of the complex production networks: even special TCP variants are in many cases 10x away from optimal performance. We argue this is due to a fundamental architectural deficiency in TCP: hardwiring packet-level event to control responses without understanding the real performance result of its action.

    Performance-oriented Congestion Control (PCC) is a new architecture that achieves consistent high performance even under challenging conditions. PCC senders continuously observe the connection between their actions and empirically experienced performance, enabling them to consistently adopt actions that result in high performance.

    Read More

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    Halfback

    Low latency short flow delivery over Internet

    Interactive applications like web browsing are sensitive to latency. Unfortunately, TCP consumes significant time in its start-up phase and loss recovery. Halfback is a new short-flow transmission mechanism that operates on a better latency-safety trade-off point: Halfback achieves lower latency than the lowest latency previous solution and at the same time significantly better safety. As Halfback is TCP-friendly and requires only sender-side changes, it is feasible to deploy.

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    Software Defined Networks in Enterprise Networks

    Ongoing and unpublished project

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    Flexible Data Center Fabric with Source Routing

    Use all available paths efficiently with scalalble source routing

    With scalable source routing mechanism, we propose a simple approach to realize the vision of a flexible, high-performance fabric: the network should expose every possible path, allowing a controller or edge device maximum choice.

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    Flexible Specturm Allocation in Cognitive Radio

    consider both time and frequency requirements of when dynamically allocate free spectrum

    We model the spectrum opportunity in a time-frequency division manner. This model caters to much more flexible requirements from secondary users (SUs) and has very clear application meaning. We solve the spectrum allocation problem by designing a combinatorial auction with truthfulness guarantee and computational efficiency.

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    Bandwitdth Allocation in Wireless Sensor Networks

    Maximizing social welfare under non-cooperative game model

    To avoid potential congestion or data loss due to the overflow of some sensor nodes, we firstly design a novel bandwidth allocation mechanism, SWM, which can maximize the social utility, an indicator of every sensor node's satisfaction degree and the social fairness. Furthermore, we model the allocation process under the SWM as a noncooperative game and find out the unique Nash Equilibrium. The uniqueness of the equilibrium demonstrates that this network will actually approach to a fair and stable state.

Currently Active Fun Projects

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    Saṃsāra

    Production-ready algorithmic trading platform using unique data insight and mining.

    Unpublished work. Out of sample 4 months backtest PL: 297% with 7.91 sharpe ratio. Live trading yields outstanding performance.

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    Clavo

    Highly failure resilient and scalable virtual private network service

    Unpublished work.

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    千爪猫(Thousand-claw Cat)

    Network-aware algorithmic trading platform

    Unpublished work.

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    SkyWalk

    Brainwave and voice controlled toy quadcopter

    An iPhone app that can let you control the DJI Phantom 3 drone with voice command and your mind command using an EEG headset.

    See a demo

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Halfback: Running Short Flows Quickly and Safely

Qingxi Li, Mo Dong, and P. Brighten Godfrey
Conference Papers International Conference on emerging Networking EXperiments and Technologies (CoNEXT), December 2015

Abstract

Interactive applications like web browsing are sensitive to latency. Unfortunately, TCP consumes significant time in its start-up phase and loss recovery. Existing sender-side optimizations use more aggressive start-up strategies to reduce latency, but at the same time they harm safety in the sense that they can damage co-existing flows’ performance and potentially the network’s overall ability to deliver data. In this paper, we experimentally compare existing solutions’ latency performance and more importantly, the trade-off between latency and safety at both the flow level and the application level. We argue that existing solutions are still operating away from the sweet spot on this trade-off plane. Based on the diagnosis of existing solutions, we introduce Halfback, a new short-flow transmission mechanism that operates on a better latency-safety trade-off point: Halfback achieves lower latency than the lowest latency previous solution and at the same time significantly better safety. As Halfback is TCP-friendly and requires only sender-side changes, it is feasible to deploy.

Towards a Flexible Data Center Fabric with Source Routing

Sangeetha Abdu Jyothi, Mo Dong, and P. Brighten Godfrey
Conference Papers ACM SIGCOMM Symposium on SDN Research (SOSR), June 2015.

Abstract

An emerging architecture for software-defined data centers and WANs is the network fabric, where complex applicationsensitive functions are factored out, leaving the network itself to provide a simple, robust high-performance data delivery abstraction. This requires performing route optimization, in real time and across a diverse choice of paths. A large variety of techniques have been proposed to provide path diversity for network fabrics. But, running up against the constraint of forwarding table size, these proposals are topology-dependent, complex, and still only provide limited path choice which (we show) can impact performance. We propose a simple approach to realize the vision of a flexible, high-performance fabric: the network should expose every possible path, allowing a controller or edge device maximum choice. To this end, we observe that source routing can be encoded and processed compactly into a single field, even in large networks, with OpenFlow 1.3. We show that, in addition to the expected decrease in required forwarding table size, source routing supports optimal throughput performance, in some cases significantly higher than some past proposals. We thus believe source routing offers a clean abstraction and efficient implementation for future network fabrics.

PCC: Re-architecting Congestion Control for Consistent High Performance

Mo Dong, Qingxi Li, Doron Zarchy, P. Brighten Godfrey, and Michael Schapira.
Conference Papers 12th USENIX Symposium on Networked Systems Design and Implementation (NSDI), April 2015.

Abstract

TCP and its variants have suffered from surprisingly poor performance for decades. We argue the TCP family has little hope of achieving consistent high performance due to a fundamental architectural deficiency: hardwiring packet-level events to control responses. We propose Performance-oriented Congestion Control (PCC), a new congestion control architecture in which each sender continuously observes the connection between its actions and empirically experienced performance, enabling it to consistently adopt actions that result in high performance. We prove that PCC converges to a stable and fair equilibrium. Across many real-world and challenging environments, PCC shows consistent and often 10× performance improvement, with better fairness and stability than TCP. PCC requires no router hardware support or new packet format.

Rethinking Congestion Control Architecture: Performance-oriented Congestion Control

Mo Dong, Qingxi Li, Doron Zarchy, P. Brighten Godfrey, and Michael Schapira.
Conference Papers Demo in Proc. of the ACM Special Interest Group on Data Communication 2014 (SIGCOMM 2014), Chicago, IL, 2014.

Two Dimension Spectrum Allocation for Cognitive Radio Networks

Changle Li, Zhe Liu, Xiaoyan Geng, Mo Dong, Feng Yang, Xiaoying Gan, Xiaohua Tian, Xinbing Wang:
Journal Paper IEEE Transactions on Wireless Communications 13(3): 1410-1423 (2014)

Abstract

Although a substantial amount of research has examined the constructs of warmth and competence, far less has examined how these constructs develop and what benefits may accrue when warmth and competence are cultivated. Yet there are positive consequences, both emotional and behavioral, that are likely to occur when brands hold perceptions of both. In this paper, we shed light on when and how warmth and competence are jointly promoted in brands, and why these reputations matter.

Combinatorial auction with time-frequency flexibility in cognitive radio networks

Mo Dong, Gaofei Sun, Xinbing Wang, Qian Zhang
Conference Papers The 31st Annual IEEE International Conference on Computer Communications (INFOCOM), April, 2012

Abstract

In this paper, we tackle the spectrum allocation problem in cognitive radio (CR) networks with time-frequency flexibility consideration using combinatorial auction. Different from all the previous works using auction mechanisms, we model the spectrum opportunity in a time-frequency division manner. This model caters to much more flexible requirements from secondary users (SUs) and has very clear application meaning. The additional flexibility also brings theoretical and computational difficulties. We model the spectrum allocation as a combinatorial auction and show that under the time-frequency flexible model, reaching the social welfare maximal is NP hard and the upper bound of worst-case approximation ratio is √m, m is the number of time-frequency slots. Therefore, we design an auction mechanism with near-optimal winner determination algorithm, whose worst-case approximation ratio reaches the upper bound √m. Further we devise a truthful payment scheme under the approximation winner determination algorithm to guarantee that all the bids submitted by SUs reflect their true valuation of the spectrum. To further address the issue and reach optimality, we simplify the general model to that only frequency flexibility is allowed, which is still useful, and propose a truthful, optimal and computationally efficient auction mechanism under modified model. Extensive simulation results show that all the proposed algorithms generate high social welfare as well as high spectrum utilization ratio. What's more, the actual approximation ratio of near-optimal algorithm is much higher than the worst-case approximation ratio.

Non-Cooperative Game Based Social Welfare Maximizing Bandwidth Allocation in WSNs

Mo Dong, Haiming Jin, Gaofei Sun, Xinbing Wang, Wei Liu, Xudong Wang
Conference Papers The IEEE Global Communications Conference (GLOBECOM), December, 2011

Abstract

In this paper, we deal with possible data transmission congestion on the sink node in wireless sensor networks (WSNs). We consider a scenario in which all the sensor nodes have a certain amount of storage space and acquire data from the surroundings at heterogeneous speed. Because receiving bandwidth of the sink node is limited, a proper bandwidth allocation mechanism should be implemented to avoid possible congestion or data loss due to the overflow of some sensor nodes. To address this problem, we firstly design a novel bandwidth allocation mechanism, SWM, that can maximize the social utility, an indicator of every sensor node's satisfaction degree and the social fairness. Furthermore, we model the allocation process under the SWM as a noncooperative game and figure out the unique Nash Equilibrium. The uniqueness of the equilibrium demonstrates that this network will actually approach to a fair and stable state.

Opportunistic Spectrum Access to 3G Wireless CDMA Networks for Cognitive RadioCooperative Game Based Social Welfare Maximizing Bandwidth Allocation in WSNs

Gaofei Sun, Mo Dong, Youyun Xu, Xinbing Wang, Mohsen Guizani
Conference Papers ICC, 2011
  • Present 2012.09

    Research Assistant

    University of Illinois at Urbana Champaign, Adivsor: Dr. Brighten Godfrey

    Besides all my research work, I also help to design and maintain the OCEAN networking testbed

  • 2013.08 2013.05

    Member of Technical Staff Intern

    Nicira Team, VMware, Mentor: Igor Ganichev

    Implemented first version of Traceflow backend, a tool to diagnose and analysze virtual network configuration errors for VMware's NSX network virtualization platform. Implementing Traceflow required understanding of most of NSX's complicated software layers and learning of a new declarative language nlog.

  • 2012.05 2009.10

    Co-founder

    同去网 (Tongqu.me)

    Tongqu.me help university students discover offline university related events resources, such as parties, training courses, academic talks and technology meetups and find people with the same interests.

    I co-founded the company and worked on both the marketing side and technology (built a natural language process engine and QR code electric tickets system) side of the company. The website now is the main hub of student activity of my undergrad university.

  • 2012.06 2009.09

    Research Assistant

    Insititute of Wireless Communication, Shanghai Jiao Tong University, Advisor: Dr. Xinbing Wang

    I worked on interdisciplinary research of wireless networks and Game Theory, please click the research tab for detail.