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Page 1: 3 Temporal Spatial S Each sensor has a unique geospatial … · 2020-06-04 · GeoMAN: Multi-level Attention Networks for Geo-sensory Time Series Prediction Yuxuan Liang1,2, Songyu

GeoMAN: Multi-level Attention Networks for Geo-sensory Time Series Prediction

Yuxuan Liang1,2, Songyu Ke3,2, Junbo Zhang2,4, Xiuwen Yi4,2, Yu Zheng2,1,3,4

1 Xidian University, Xi an, China2 Urban Computing Business Unit, JD Finance, Beijing, China3 Shanghai Jiao Tong University, Shanghai, China4 Southwest Jiaotong University, Chengdu, China

Codes & Data

Temporal Attn

Conca

t

External Factor Fusion Multi-level Attention Network

LSTM

LSTM

LSTMTime Features Embed

Weather Forecasts Embed

SensorID Embed

POIs & Sensor NetworksDecoder

LSTM

Spatial Attn

LSTM

Spatial Attn

LSTM

Spatial Attn

POIs Model Input

h0

Spatial AttentionEncoder

Local Global

Concat

tc

1tc

c

1ˆ i

ty

ˆ i

ty

ˆ iy

Sensor Networks

Meteorology

Geo-sensoryTime series

Time

Methodology

Spatial Attention Capture dynamic inter-sensor correlation

Local: adaptively captures the correlation between target series and local features (other series)

Global: adaptively select the relevant sensors to make predictions

Temporal Attention

Select relevant historical time slots to make predictions

Model Training

Encoder-decoder + Multi-level attention

GeoMAN is smooth and differentiable

Loss function: MSE

Optimizer: Adam

tanh tanh tanh

softmax

... ...

... ...

... ...

concat

tanh tanh tanh

softmax

... ...

... ...

... ...

concat

similarity matrix Local Attn Global Attn

Concat

(a) Air quality stations in Beijing

0

3

6

9

S6 S11 S16 S23S1

(c) Plot of global spatial attention weights

(b) Plot of local spatial attention weights

Remote sensors

0

3

6

9

Wind speed towards different directionsAir pollutants

Southeast

wind

Hu

mid

ity

NO

2

Tem

per

atur

e

En

cod

er

Ste

p

En

cod

er

Ste

p

S13

S0

S1

S11

S6

S13

S17 S32

S23

S27 S26

S3

S4S16

Target sensor Discussed sensor

Results Visualization

Introduction

Geo-sensory time series Properties

Examples

GoalS4 S2

S3

Time

S1

Spatial

correlation

Temporal

correlation

t1

t3

t4

t2

t1

t2

t3

t4

t1

t2

t1

t2

t3

t5

Sudden change

Each sensor has a unique geospatial location

Reporting time series readings about different measurements

With geospatial correlation between their readings

Challenges Affected by many factors

Dynamic inter-sensor correlation

Dynamic temporal correlation

Readings of previous time interval

Readings of nearby sensors

External factors

Day 1 Day 2 Predict target series of a sensor over several future hours

Framework

External factors fusion module

Multi-level attention network Spatial attention

Temporal attention

Datasets: water quality dataset & air quality dataset

Insight

Local

Information

Sensor

Correlation

Unobserved factors Temporal factors Spatial factors

Sensor

Networks

Land

Function

POIs Time Weather

External

Factors

Target

Series

Global

Readings

Local

Readings

Local ViewGlobal View

Encoder Decoder

Sensors

Roads

Volume: 32

Speed: 50km/h

SensorsPipelines

RC: 0.84

pH: 7.1

Turbidity: 0.54

TimeWeather

POIs Sensor Network

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