Step detection XML

The WorkDag contains the description of the dataflow. Its immediate sub-elements are "mills," logical steps in the computation. The DAG may specify many inputs (sensor mills) but has only one output mill, specified by the WorkDag attribute resultCollectionName. <xml> <?xml version="1.0" standalone="no"?>

<WorkDag resultCollectionName="features"

       maxCheckupPeriod="1000000" >

</xml> We instantiate the accelerometer sensor mill. All sensor mills use only the UPDATE_UNCONDITIONAL update policy. The sample period is given in microseconds. Note that this sample period is only a cross-check; it is ultimately determined by msb-server from /msp/msb.ini. 1953 μs corresponds to 512 Hz. <xml>

 <Sensor name="accel"
         updatePolicy="UPDATE_UNCONDITIONAL"
         sampPeriod="1953"
 />

</xml> <xml>

 <ShortMag name="accelmag"
         srcName="accel"
         updatePolicy="UPDATE_BY_SRC_PIGGYBACK"
 />

 <Fft16 name="accelmag_fft"
         srcName="accelmag"
         updatePolicy="UPDATE_BY_NUM_NEW_SRC_SAMP"
         numSrcSampPerUpdate="1024"
         numSrcSampRqd="2048"
 />

 <EnergyThreshold name="accelmag_fft_thresholded"
         srcName="accelmag_fft"
         updatePolicy="UPDATE_BY_SRC_PIGGYBACK"
         threshold="250000"
 />

 <EnergyFilter name="accelmag_fft_filtered"
         srcName="accelmag_fft_thresholded"
         updatePolicy="UPDATE_BY_SRC_PIGGYBACK"
         threshold=".16"
 />

 <Fft16I name="accelmag_smooth"
         srcName="accelmag_fft_filtered"
         updatePolicy="UPDATE_BY_SRC_PIGGYBACK"
         overlap="1"
 />

 <IntegerFirFilter name="deriv"
         srcName="accelmag_smooth"
         updatePolicy="UPDATE_BY_NUM_NEW_SRC_SAMP"
         numSrcSampPerUpdate="1" >
   2 1 0 -1 -2
 </IntegerFirFilter>

 <ZeroCross name="peaks_max"
         srcName="deriv"
         updatePolicy="UPDATE_BY_SRC_PIGGYBACK"
         edge="falling"
 />
 
 <TimeDiffLim name="peaks_max_sane"
         srcName="peaks_max"
         updatePolicy="UPDATE_BY_SRC_PIGGYBACK"
         minSamps="16"
         maxSamps="512"
 />

 <WinSum name="steps_05s"
         srcName="peaks_max_sane"
         updatePolicy="UPDATE_BY_NUM_NEW_SRC_SAMP"
         numSrcSampPerUpdate="128"
         windowLength="2560"
 />

 <TimeDiffShort name="stridelength"
         srcName="peaks_max_sane"
         updatePolicy="UPDATE_BY_SRC_PIGGYBACK"
         windowLength="16"
         deltaMax="512"
 />

 <SplitShort name="stridelength_mean"
         srcName="stridelength"
         updatePolicy="UPDATE_BY_SRC_PIGGYBACK"
         componentName="mean"
 />

 <SplitShort name="stridelength_stddev"
         srcName="stridelength"
         updatePolicy="UPDATE_BY_SRC_PIGGYBACK"
         componentName="stddev"
 />

 <Collection name="debug"
         updatePolicy="UPDATE_BY_PERIOD"
         sampPeriod="1953" >
   <component name="accelmag" />
   <component name="accelmag_smooth" />
   <component name="deriv" />
   <component name="peaks_max_sane" />
 </Collection>

 <Collection name="features"
         updatePolicy="UPDATE_BY_PERIOD"
         sampPeriod="250000" >
   <component name="steps_05s" />
   <component name="stridelength_mean" />
   <component name="stridelength_stddev" />
 </Collection>

</WorkDag> </xml>