HTM For Short Term Arterial Traffic Prediction

papers

#1

A lot of my research has been evaluating models for short term arterial traffic prediction on urban roads and I finally got a paper published on it in IEEE TITS!

https://ieeexplore.ieee.org/document/8424074/

It took so long to get through that nupic switched to SDR classifier from CLA classifier during the process and the description of the TM layer isn’t explained in the best way.

I might make my thesis available here if anyone is interested which would be way more comprehensive in terms of experiments and explanation.


HTM and Deep learning
#3

I’d like to see it for sure. Definitely curious how you matched the data types to encodings and how you set it up in general.


#4

This paper is behind a paywall for most users of this forum.


#5

Congrats on the publication! I know it was a lot of work. :wink:


#6

All my code is here: https://github.com/JonnoFTW/htm-models-adelaide/tree/master/engine

That code is actually quite old though, parameters in later work are selected by distributed (read: I overtook my school’s computer lab) hyper-parameter optimisation using TPE (and not the included swarming methods that come with nupic).

The best encoding for my data is:

  • DateEncoder for weekend, timeofday, dayofweek, holidays (using the improved holiday extensions I pushed to nupic)
  • RDSE for flow with resolution= max(0.001,(max_flow-1)/flow_buckets)

My best model with an RMSE of 9.31. I optimised over this space:

    columnCount = 2048
    max_flow = _max_flow
    flow_buckets = {{quniform(1, 40, 1)}}
    synPermConnected = {{uniform(0.05, 0.25)}}
    activeColumns = {{quniform(20, 64, 1)}}
    synPermInactiveDec = {{uniform(0.0003, 0.1)}}
    synPermActiveInc = {{uniform(0.001, 0.1)}}
    potentialPct = {{uniform(0.2, 0.85)}}
    activationThreshold = {{quniform(5, 20, 1)}}
    pamLength = {{quniform(1, 10, 1)}}
    cellsPerColumn = {{quniform(8, 32, 2)}}
    minThreshold = {{quniform(4, 32, 1)}}
    alpha = {{uniform(0.0001, 0.2)}}
    boost = {{uniform(0.0, 0.1)}}
    tmPermanenceInc = {{uniform(0.05, 0.2)}}
    maxSynapsesPerSegment = {{quniform(28, 72, 2)}}
    newSynapseRatio = {{uniform(0.4, 0.8)}}
    newSynapseCount = maxSynapsesPerSegment * newSynapseRatio
    initialPerm = {{uniform(0.1, 0.33)}}
    maxSegmentsPerCell = {{quniform(32, 66, 2)}}
    permanenceDec = {{uniform(0.01, 0.2)}}
    weekend_width = {{quniform(30, 150, 2)}}
    weekend_width = int(1+weekend_width)
    timeOfDay_width = {{quniform(16, 201, 2)}}
    timeOfDay_width = int(1 + timeOfDay_width)
    dayOfWeek_width = {{quniform(20, 201, 2)}}
    dayOfWeek_width = int(1 + dayOfWeek_width)
    # must always be odd
    holiday_width = {{quniform(16,201,2)}}
    holiday_width = int(1 + holiday_width)
    dayOfWeek_radius = {{uniform(6, 15)}}
    timeOfDay_radius = {{uniform(6, 15)}}
    weekend_radius = {{uniform(6, 15)}}

I also optimised over 512, 1024 and 2048 columns and basically you only get better model runtimes with slightly worse RMSE score (best was 10.4 for 1024 and 512). I honestly think there’s a lower limit to how well you can predict traffic flow without a literal timemachine.

Anyway the best model params for my problem are (I hope someone can learn something here from the chosen parameters, because it’s insanely difficult to tell which parameters or their combination have the most significant impact on performance beyond column count):

{
    "aggregationInfo" : {
        "seconds" : NumberInt(0), 
        "fields" : [

        ], 
        "months" : NumberInt(0), 
        "days" : NumberInt(0), 
        "years" : NumberInt(0), 
        "hours" : NumberInt(0), 
        "microseconds" : NumberInt(0), 
        "weeks" : NumberInt(0), 
        "minutes" : NumberInt(0), 
        "milliseconds" : NumberInt(0)
    }, 
    "model" : "HTMPrediction", 
    "version" : NumberInt(1), 
    "predictAheadTime" : null, 
    "modelParams" : {
        "sensorParams" : {
            "verbosity" : NumberInt(0), 
            "encoders" : {
                "datetime_timeOfDay" : {
                    "type" : "DateEncoder", 
                    "timeOfDay" : [
                        NumberInt(55), 
                        11.389925472016568
                    ], 
                    "fieldname" : "datetime", 
                    "name" : "datetime_timeOfDay"
                }, 
                "flow" : {
                    "type" : "RandomDistributedScalarEncoder", 
                    "resolution" : 89.25, 
                    "fieldname" : "flow", 
                    "name" : "flow"
                }, 
                "datetime_weekend" : {
                    "weekend" : [
                        NumberInt(127), 
                        12.654411787919452
                    ], 
                    "fieldname" : "datetime", 
                    "name" : "datetime_weekend", 
                    "type" : "DateEncoder"
                }, 
                "datetime_holiday" : {
                    "type" : "DateEncoder", 
                    "holiday" : NumberInt(133), 
                    "fieldname" : "datetime", 
                    "name" : "datetime_holiday", 
                    "holidays" : [
                        [
                            NumberInt(2015), 
                            NumberInt(12), 
                            NumberInt(25)
                        ], 
                        [
                            NumberInt(2016), 
                            NumberInt(12), 
                            NumberInt(31)
                        ], 
                        [
                            NumberInt(2015), 
                            NumberInt(10), 
                            NumberInt(5)
                        ], 
                        [
                            NumberInt(2015), 
                            NumberInt(4), 
                            NumberInt(6)
                        ], 
                        [
                            NumberInt(2017), 
                            NumberInt(1), 
                            NumberInt(26)
                        ], 
                        [
                            NumberInt(2016), 
                            NumberInt(12), 
                            NumberInt(27)
                        ], 
                        [
                            NumberInt(2016), 
                            NumberInt(4), 
                            NumberInt(25)
                        ], 
                        [
                            NumberInt(2015), 
                            NumberInt(6), 
                            NumberInt(8)
                        ], 
                        [
                            NumberInt(2015), 
                            NumberInt(4), 
                            NumberInt(4)
                        ], 
                        [
                            NumberInt(2015), 
                            NumberInt(3), 
                            NumberInt(9)
                        ], 
                        [
                            NumberInt(2015), 
                            NumberInt(1), 
                            NumberInt(1)
                        ], 
                        [
                            NumberInt(2017), 
                            NumberInt(4), 
                            NumberInt(14)
                        ], 
                        [
                            NumberInt(2017), 
                            NumberInt(4), 
                            NumberInt(17)
                        ], 
                        [
                            NumberInt(2015), 
                            NumberInt(1), 
                            NumberInt(26)
                        ], 
                        [
                            NumberInt(2016), 
                            NumberInt(3), 
                            NumberInt(14)
                        ], 
                        [
                            NumberInt(2017), 
                            NumberInt(10), 
                            NumberInt(2)
                        ], 
                        [
                            NumberInt(2017), 
                            NumberInt(12), 
                            NumberInt(31)
                        ], 
                        [
                            NumberInt(2017), 
                            NumberInt(6), 
                            NumberInt(12)
                        ], 
                        [
                            NumberInt(2017), 
                            NumberInt(1), 
                            NumberInt(1)
                        ], 
                        [
                            NumberInt(2017), 
                            NumberInt(12), 
                            NumberInt(25)
                        ], 
                        [
                            NumberInt(2016), 
                            NumberInt(10), 
                            NumberInt(3)
                        ], 
                        [
                            NumberInt(2015), 
                            NumberInt(4), 
                            NumberInt(25)
                        ], 
                        [
                            NumberInt(2017), 
                            NumberInt(3), 
                            NumberInt(13)
                        ], 
                        [
                            NumberInt(2017), 
                            NumberInt(4), 
                            NumberInt(25)
                        ], 
                        [
                            NumberInt(2017), 
                            NumberInt(12), 
                            NumberInt(24)
                        ], 
                        [
                            NumberInt(2015), 
                            NumberInt(4), 
                            NumberInt(3)
                        ], 
                        [
                            NumberInt(2016), 
                            NumberInt(3), 
                            NumberInt(26)
                        ], 
                        [
                            NumberInt(2016), 
                            NumberInt(12), 
                            NumberInt(24)
                        ], 
                        [
                            NumberInt(2016), 
                            NumberInt(3), 
                            NumberInt(25)
                        ], 
                        [
                            NumberInt(2016), 
                            NumberInt(3), 
                            NumberInt(28)
                        ], 
                        [
                            NumberInt(2016), 
                            NumberInt(12), 
                            NumberInt(26)
                        ], 
                        [
                            NumberInt(2015), 
                            NumberInt(12), 
                            NumberInt(31)
                        ], 
                        [
                            NumberInt(2017), 
                            NumberInt(4), 
                            NumberInt(15)
                        ], 
                        [
                            NumberInt(2016), 
                            NumberInt(1), 
                            NumberInt(26)
                        ], 
                        [
                            NumberInt(2016), 
                            NumberInt(1), 
                            NumberInt(1)
                        ], 
                        [
                            NumberInt(2015), 
                            NumberInt(12), 
                            NumberInt(24)
                        ], 
                        [
                            NumberInt(2017), 
                            NumberInt(1), 
                            NumberInt(2)
                        ], 
                        [
                            NumberInt(2016), 
                            NumberInt(6), 
                            NumberInt(13)
                        ], 
                        [
                            NumberInt(2015), 
                            NumberInt(12), 
                            NumberInt(28)
                        ], 
                        [
                            NumberInt(2017), 
                            NumberInt(12), 
                            NumberInt(26)
                        ]
                    ]
                }, 
                "datetime_dayOfWeek" : {
                    "dayOfWeek" : [
                        NumberInt(133), 
                        11.099369381130948
                    ], 
                    "type" : "DateEncoder", 
                    "fieldname" : "datetime", 
                    "name" : "datetime_dayOfWeek"
                }
            }, 
            "sensorAutoReset" : null
        }, 
        "anomalyParams" : {
            "anomalyCacheRecords" : null, 
            "autoDetectThreshold" : null, 
            "autoDetectWaitRecords" : null
        }, 
        "spParams" : {
            "columnCount" : NumberInt(2048), 
            "spVerbosity" : NumberInt(0), 
            "spatialImp" : "cpp", 
            "inputWidth" : NumberInt(0), 
            "synPermInactiveDec" : 0.06321542545086611, 
            "synPermConnected" : 0.05762102903677198, 
            "synPermActiveInc" : 0.08360575341845242, 
            "seed" : NumberInt(1956), 
            "numActiveColumnsPerInhArea" : NumberInt(56), 
            "boostStrength" : 0.007220744757166206, 
            "globalInhibition" : NumberInt(1), 
            "potentialPct" : 0.7573713625971066
        }, 
        "trainSPNetOnlyIfRequested" : false, 
        "clParams" : {
            "alpha" : 0.04423326056698039, 
            "verbosity" : NumberInt(0), 
            "steps" : "1", 
            "regionName" : "SDRClassifierRegion"
        }, 
        "tmParams" : {
            "columnCount" : NumberInt(2048), 
            "activationThreshold" : NumberInt(8), 
            "pamLength" : NumberInt(5), 
            "cellsPerColumn" : NumberInt(14), 
            "permanenceInc" : 0.05875552578940036, 
            "minThreshold" : NumberInt(31), 
            "verbosity" : NumberInt(0), 
            "maxSynapsesPerSegment" : NumberInt(50), 
            "outputType" : "normal", 
            "globalDecay" : 0.0, 
            "initialPerm" : 0.11619888545169564, 
            "permanenceDec" : 0.05872729523847874, 
            "seed" : NumberInt(1960), 
            "maxAge" : NumberInt(0), 
            "newSynapseCount" : NumberInt(33), 
            "maxSegmentsPerCell" : NumberInt(44), 
            "temporalImp" : "cpp", 
            "inputWidth" : NumberInt(2048)
        }, 
        "tmEnable" : true, 
        "clEnable" : true, 
        "spEnable" : true, 
        "inferenceType" : "TemporalMultiStep"
    }
}

#7

Thanks @Jonathan_Mackenzie! I’m pumped to have all this for reference, and impressed with the depth of your work. As a likely user of HTM in this area I obviously appreciate your exploring this space and paving the way. Big ups :+1::vulcan_salute:


#8

No problem, really the field of Intelligent transportation systems is ripe for online learning and big data in general.


#9

For those of you interested in traffic analysis with HTM… although this is really out of date and probably doesn’t work anymore (no I will not work on it): It shows the possibilities.