// methods
public Detector calibrateParameters(Detector d) {
if (d.getHealthStatus() != 100) { // assign NaN if detector is bad
vf = Double.NaN;
w = Double.NaN;
q_max = Double.NaN;
} else {
// organize into an array of DataPoint
ArrayList<DataPoint> datavec = new ArrayList<DataPoint>();
int i;
for (i = 0; i < d.getDensityData().size(); i++)
datavec.add(
new DataPoint(
d.getDensityData().get(i), d.getFlowData().get(i), d.getSpeedData().get(i)));
// maximum flow and its corresponding density
DataPoint maxflw = new DataPoint(0, Double.NEGATIVE_INFINITY, 0);
for (i = 0; i < d.getFlowData().size(); i++)
if (datavec.get(i).flw > maxflw.flw) maxflw.setval(datavec.get(i));
q_max = maxflw.flw;
// split data into congested and freeflow regimes ...............
ArrayList<DataPoint> congestion = new ArrayList<DataPoint>(); // congestion states
ArrayList<DataPoint> freeflow = new ArrayList<DataPoint>(); // freeflow states
for (i = 0; i < d.getDensityData().size(); i++)
if (datavec.get(i).dty >= maxflw.dty) congestion.add(datavec.get(i));
else freeflow.add(datavec.get(i));
// vf is the average freeflow speed
vf = percentile("spd", freeflow, 0.5f);
// compute critical density
rho_crit = q_max / vf;
// BINNING
ArrayList<DataPoint> supercritical = new ArrayList<DataPoint>(); // data points above rho_crit
for (i = 0; i < d.getDensityData().size(); i++)
if (datavec.get(i).dty >= rho_crit) supercritical.add(datavec.get(i));
// sort supercritical w.r.t. density
Collections.sort(supercritical);
int numsupercritical = supercritical.size();
int Bin_width = 10;
int step = Bin_width;
ArrayList<DataPoint> BinData = new ArrayList<DataPoint>();
for (i = 0; i < numsupercritical; i += Bin_width) {
if (i + Bin_width >= numsupercritical) step = numsupercritical - i;
if (step != 0) {
List<DataPoint> Bin = (List<DataPoint>) supercritical.subList(i, i + step);
if (!Bin.isEmpty()) {
double a = 2.5f * percentile("flw", Bin, 0.75f) - 1.5f * percentile("flw", Bin, 0.25f);
double b = percentile("flw", Bin, 1f);
BinData.add(new DataPoint(percentile("dty", Bin, 0.5f), Math.min(a, b), Float.NaN));
}
}
}
// Do constrained LS
ArrayList<Double> ai = new ArrayList<Double>();
ArrayList<Double> bi = new ArrayList<Double>();
for (i = 0; i < BinData.size(); i++) {
bi.add(q_max - BinData.get(i).flw);
ai.add(BinData.get(i).dty - rho_crit);
}
if (BinData.size() > 0) {
float sumaibi = 0;
float sumaiai = 0;
for (i = 0; i < BinData.size(); i++) {
sumaibi += ai.get(i) * bi.get(i);
sumaiai += ai.get(i) * ai.get(i);
}
w = (double) (sumaibi / sumaiai);
w = Math.max(w, w_min);
w = Math.min(w, w_max);
} else {
w = Double.NaN;
}
}
// store parameters in sensor
d.setFdParams(new FDParameters()); // assigns nominal
d.getFdParams().setFD(vf, w, q_max); // assigns calculated values, keeps nominals if NaN
return d;
}