Square root approximation of twd delta std for duration dimension

java/com.sap.sailing.windestimation/src/com/sap/sailing/windestimation/model/regressor/twdtransition/DistanceBasedTwdTransitionRegressorModelMetadata.java

@@ -16,7 +16,13 @@ public class DistanceBasedTwdTransitionRegressorModelMetadata
 
     @Override
     public double getDimensionValue(TwdTransition instance) {
-        return instance.getDistance().getMeters();
+        double meters = instance.getDistance().getMeters();
+        return getPreprocessedDimensionValue(meters);
+    }
+
+    @Override
+    public double getPreprocessedDimensionValue(double meters) {
+        return meters;
     }
 
     public enum DistanceValueRange {

java/com.sap.sailing.windestimation/src/com/sap/sailing/windestimation/model/regressor/twdtransition/DurationBasedTwdTransitionRegressorModelMetadata.java

@@ -16,7 +16,16 @@ public class DurationBasedTwdTransitionRegressorModelMetadata
 
     @Override
     public double getDimensionValue(TwdTransition instance) {
-        return instance.getDuration().asSeconds();
+        double seconds = instance.getDuration().asSeconds();
+        return getPreprocessedDimensionValue(seconds);
+    }
+
+    @Override
+    public double getPreprocessedDimensionValue(double seconds) {
+        if (getSupportedDimensionValueRange().equals(DurationValueRange.MIDDLE1.getSupportedDimensionValueRange())) {
+            seconds = Math.sqrt(seconds);
+        }
+        return seconds;
     }
 
     public enum DurationValueRange {

java/com.sap.sailing.windestimation/src/com/sap/sailing/windestimation/model/regressor/twdtransition/SingleDimensionBasedTwdTransitionRegressorModelMetadata.java

@@ -23,6 +23,8 @@ public abstract class SingleDimensionBasedTwdTransitionRegressorModelMetadata
     }
 
     public abstract double getDimensionValue(TwdTransition instance);
+    
+    public abstract double getPreprocessedDimensionValue(double dimensionValue);
 
     public SupportedDimensionValueRange getSupportedDimensionValueRange() {
         return supportedDimensionValueRange;