2 research outputs found
An Incomplete Tensor Tucker decomposition based Traffic Speed Prediction Method
In intelligent transport systems, it is common and inevitable with missing
data. While complete and valid traffic speed data is of great importance to
intelligent transportation systems. A latent factorization-of-tensors (LFT)
model is one of the most attractive approaches to solve missing traffic data
recovery due to its well-scalability. A LFT model achieves optimization usually
via a stochastic gradient descent (SGD) solver, however, the SGD-based LFT
suffers from slow convergence. To deal with this issue, this work integrates
the unique advantages of the proportional-integral-derivative (PID) controller
into a Tucker decomposition based LFT model. It adopts two-fold ideas: a)
adopting tucker decomposition to build a LFT model for achieving a better
recovery accuracy. b) taking the adjusted instance error based on the PID
control theory into the SGD solver to effectively improve convergence rate. Our
experimental studies on two major city traffic road speed datasets show that
the proposed model achieves significant efficiency gain and highly competitive
prediction accuracy
Correlating sparse sensing for large-scale traffic speed estimation: A Laplacian-enhanced low-rank tensor kriging approach
Traffic speed is central to characterizing the fluidity of the road network.
Many transportation applications rely on it, such as real-time navigation,
dynamic route planning, and congestion management. Rapid advances in sensing
and communication techniques make traffic speed detection easier than ever.
However, due to sparse deployment of static sensors or low penetration of
mobile sensors, speeds detected are incomplete and far from network-wide use.
In addition, sensors are prone to error or missing data due to various kinds of
reasons, speeds from these sensors can become highly noisy. These drawbacks
call for effective techniques to recover credible estimates from the incomplete
data. In this work, we first identify the issue as a spatiotemporal kriging
problem and propose a Laplacian enhanced low-rank tensor completion (LETC)
framework featuring both lowrankness and multi-dimensional correlations for
large-scale traffic speed kriging under limited observations. To be specific,
three types of speed correlation including temporal continuity, temporal
periodicity, and spatial proximity are carefully chosen and simultaneously
modeled by three different forms of graph Laplacian, named temporal graph
Fourier transform, generalized temporal consistency regularization, and
diffusion graph regularization. We then design an efficient solution algorithm
via several effective numeric techniques to scale up the proposed model to
network-wide kriging. By performing experiments on two public million-level
traffic speed datasets, we finally draw the conclusion and find our proposed
LETC achieves the state-of-the-art kriging performance even under low
observation rates, while at the same time saving more than half computing time
compared with baseline methods. Some insights into spatiotemporal traffic data
modeling and kriging at the network level are provided as well