| NSF Org: |
CNS Division Of Computer and Network Systems |
| Recipient: |
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| Initial Amendment Date: | July 5, 2017 |
| Latest Amendment Date: | July 5, 2017 |
| Award Number: | 1717041 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Alhussein Abouzeid
aabouzei@nsf.gov (703)292-0000 CNS Division Of Computer and Network Systems CSE Direct For Computer & Info Scie & Enginr |
| Start Date: | July 1, 2017 |
| End Date: | January 31, 2022 (Estimated) |
| Total Intended Award Amount: | $500,000.00 |
| Total Awarded Amount to Date: | $500,000.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
3 RUTGERS PLZ NEW BRUNSWICK NJ US 08901-8559 (848)932-0150 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
671 US Highway 1 North Brunswick NJ US 08902-3390 |
| Primary Place of Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Networking Technology and Syst |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.070 |
ABSTRACT
With the emergence of cyber-physical systems, real-time status updates have become an important and ubiquitous form of communication. Applications that employ vehicular status messages, security reports from computers, homes, and offices, and surveillance video from remote-controlled systems need status updates to be as timely as possible; however, this is typically constrained by limited network resources. This tension has led to the introduction of new performance metrics based on the Age of Information (AoI) that capture how timely is one's knowledge of a system or process. AoI-based optimization of both the network service facility and the senders' updating policies has yielded new and even surprising results that ultimately will increase the reliability of vehicular safety warning systems, reduce the bandwidth needed for video monitoring, and increase the energy efficiency of sensor networks.
Much of this recent work has been directed toward an analytic understanding of AoI using mathematical models. While the analysis of basic models and methods needs to continue, the merits of AoI also need to be studied in the context of specific applications. Thus, this project has four components: (1) State Dependent Updating: the update submission process will be optimized for a source that is subject to energy and power constraints in sending updates through a time-varying service facility. (2) Status Update Multiple Access: new protocols will be designed for wireless sensors sending updates through a shared random access channel. (3) Real-time Universal Data Compression: for a discrete random source with unknown statistics, the AoI performance of universal streaming source coding systems will be characterized. (4) Remote Video Updating: the AoI metric will be used to study how H.264 video frames should be delivered for machine-based surveillance. The first three project components will aim for new mathematical insights, methods and algorithms in fundamental problem areas. The fourth component, video updating, represents an application area to which these methods and algorithms will be applied.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Time-sensitive cyberphysical system applications continue to grow in importance. Camera images from vehicles are used to describe the surroundings. Video streams are augmented with informative labels. Sensor data needs to be gathered and analyzed to detect anomalies. A remote surgery system needs to update the positions of the surgical tools. These examples share a common description: a source gathers and processes measurements in order to generate time-stamped status update messages that are transmitted through a network to one or more monitors. Awareness of the state of the remote sensor or system needs to be as timely as possible at the monitors for the system to function properly.
This project aimed to characterize timeliness based on the Age of Information (AoI). Age measures how old is the most recent update received by a monitor and the AoI is the average age at the monitor. In this project, we developed new tools for the evaluation of AoI based on a model of randomness known as a stochastic hybrid system (SHS). These SHS tools were applied to a broad range of update processing and delivery systems that were previously considered too complex for AoI analysis. This included queueing systems that deliver updates of multiple types, networks that forward updates over sequence of multiple network links, and distributed storage systems in which each update is replicated in multiple locations, in order to be retrieved by a large number of readers. This project also included work on ACP, a practical end-to-end ?Age Control Protocol? for regulating the flow of updates across an Internet connection. Relative to the traditional TCP protocol, ACP drastically reduced the packet sending rate without increasing the AoI.
A final research direction for this project examined protocols that randomly spread updates around the network, analogous to the spread of gossip. The challenge in this system was accounting for the random circulation of ?old news.? This work solved a key technical barrier in tracking how up-to-date each network node is by developing a method for discarding the old news. This new technique enabled the characterization of the age of gossip as a function of the number of gossiping nodes.
The broader impact of this work will be seen in how it informs the design of future networks, storage systems, and service facilities for handling time-sensitive updates.
Last Modified: 02/28/2022
Modified by: Roy D Yates
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