12 research outputs found
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Transportation system reconstruction
2035-03-17 [Patent Duration]Current Assignees: Urban Engines Inc Google LLCA system for reconstructing vehicle itinerary include a processor and a memory storing instructions, implemented by the processor, to cluster historical trip records into a plurality of clusters, each of the plurality of clusters including a set of historical trip records that describe events occurring within a predetermined time range at one location; identify a sequence of clusters that includes a cluster at each location; and estimate an itinerary for a vehicle based on the sequence of clusters and constraint data describing physical constraints, the itinerary for the vehicle describing a sequence of arrival and departure times at a sequence of locations for the vehicle
Saving mobile device energy with multipath TCP
Multipath TCP is a backwards-compatible TCP extension that en-ables using multiple network paths between two end systems for a single TCP connection, increasing performance and reliability. It can also be used to “shift ” active connections from one network path to another without breakage. This feature is especially attrac-tive on mobile devices with multiple radio interfaces, because it can be used to continuously shift active connections to the most energy-efficient network path. This paper describes a novel method for deriving such a multipath scheduler using MPTCP that maximises energy savings. Based on energy models for the different radio in-terfaces as well as a continuously accumulated communication his-tory of the device user, we compute schedulers for different appli-cations by solving a Markov decision process offline. We evaluate these schedulers for a large number of random application mod-els and selected realistic applications derived from measurements. Evaluations based on energy models for a mobile device with Wifi and 3G radio interfaces show that it performs comparably in terms of energy efficiency to a theoretically optimal omniscient oracle scheduler
Impacts of Social Distancing Policies on Mobility and COVID-19 Case Growth in the US
Social distancing remains an important strategy to combat the COVID-19
pandemic in the United States. However, the impacts of specific state-level
policies on mobility and subsequent COVID-19 case trajectories have not been
completely quantified. Using anonymized and aggregated mobility data from
opted-in Google users, we found that state-level emergency declarations
resulted in a 9.9% reduction in time spent away from places of residence.
Implementation of one or more social distancing policies resulted in an
additional 24.5% reduction in mobility the following week, and subsequent
shelter-in-place mandates yielded an additional 29.0% reduction. Decreases in
mobility were associated with substantial reductions in case growth 2 to 4
weeks later. For example, a 10% reduction in mobility was associated with a
17.5% reduction in case growth 2 weeks later. Given the continued reliance on
social distancing policies to limit the spread of COVID-19, these results may
be helpful to public health officials trying to balance infection control with
the economic and social consequences of these policies.Comment: Co-first Authors: GAW, SV, VE, and AF contributed equally.
Corresponding Author: Dr. Evgeniy Gabrilovich, [email protected] 32 pages
(including supplemental material), 4 figures in the main text, additional
figures in the supplemental materia
Data Center Networking with Multipath TCP
Recently new data center topologies have been proposed that offer higher aggregate bandwidth and location independence by creating multiple paths in the core of the network. To effectively use this bandwidth requires ensuring different flows take different paths, which poses a challenge. Plainly put, there is a mismatch between single-path transport and the multitude of available network paths. We propose a natural evolution of data center transport from TCP to multipath TCP. We show that multipath TCP can effectively and seamlessly use available bandwidth, providing improved throughput and better fairness in these new topologies when compared to single path TCP and randomized flow-level load balancing. We also show that multipath TCP outperforms laggy centralized flow scheduling without needing centralized control or additional infrastructure
Data Center Networking with multipath TCP
Recently new data center topologies have been proposed that
offer higher aggregate bandwidth and location independence
by creating multiple paths in the core of the network. To effectively
use this bandwidth requires ensuring different flows
take different paths, which poses a challenge.
Plainly put, there is a mismatch between single-path transport
and the multitude of available network paths. We propose
a natural evolution of data center transport from TCP
to multipath TCP. We show that multipath TCP can effectively
and seamlessly use available bandwidth, providing improved
throughput and better fairness in these new topologies
when compared to single path TCP and randomized
flow-level load balancing. We also show that multipath TCP
outperforms laggy centralized flow scheduling without needing
centralized control or additional infrastructure
Improving datacenter performance and robustness with multipath TCP
The latest large-scale data centers offer higher aggregate bandwidth and robustness by creating multiple paths in the core of the network. To utilize this bandwidth requires different flows take different paths, which poses a challenge. In short, a single-path transport seems ill-suited to such networks. We propose using Multipath TCP as a replacement for TCP in such data centers, as it can effectively and seamlessly use available bandwidth, giving improved throughput and better fairness on many topologies. We investigate what causes these benefits, teasing apart the contribution of each of the mechanisms used by MPTCP. Using MPTCP lets us rethink data center networks, with a different mindset as to the relationship between transport protocols, routing and topology. MPTCP enables topologies that single path TCP cannot utilize. As a proof-of-concept, we present a dual-homed variant of the FatTree topology. With MPTCP, this outperforms FatTree for a wide range of workloads, but costs the same. In existing data centers, MPTCP is readily deployable leveraging widely deployed technologies such as ECMP. We have run MPTCP on Amazon EC2 and found that it outperforms TCP by a factor of three when there is path diversity. But the biggest benefits will come when data centers are designed for multipath transports