/// <summary>
/// Takes a probability (in [0,1]) and returns corresponding z (standard normal) value
/// </summary>
/// <param name="prob">in [0,1]</param>
/// <returns></returns>
public static double FindZ(double prob)
{
double returnZ;
int returnZIndex;
double lookUp = Math.Max(Math.Min(prob, 1.0), 0.0);
lookUp = ZTransformer.ZTransformGivenZ(lookUp);
Boolean lowerHalf = false;
if (lookUp < .5)
{
lookUp = 1 - lookUp;
lowerHalf = true;
}
returnZIndex = invZTable.Count - 1;
for (int i = 0; i < invZTable.Count - 1; i++)
{
if (lookUp <= invZTable[i].probability)
{
returnZIndex = i;
break;
}
}
returnZ = invZTable[returnZIndex].zValue;
if (lowerHalf)
{
returnZ = -returnZ;
}
return(returnZ);
}
private static void ObfuscateDoubleValue(ref DetectedAttributeValue targetDV, ref Random random)
{
double confidence = targetDV.stdDev;
double dblVal = ((DoubleValue)((DetectedAttributeValue)targetDV).value).value;
double X = random.NextDouble();
double Y = .5 - (X / 2);
double Z = ZTransformer.ZTransformGivenProbability(Y);
//double area = (double)(random.Next((int)(Z * 10), (int)(Z * -10)) / 10.0);
//obfuscate int
((DoubleValue)((DetectedAttributeValue)targetDV).value).value = (double)(Z * confidence + dblVal);
//exit
targetDV.stdDev = GetConfidence(Y) * 100;
}
private static void ObfuscateLocationValue(ref DetectedAttributeValue targetDV, ref Random random)
{
double confidence = targetDV.stdDev;
double x = ((LocationValue)((DetectedAttributeValue)targetDV).value).X;
double y = ((LocationValue)((DetectedAttributeValue)targetDV).value).Y;
double z = ((LocationValue)((DetectedAttributeValue)targetDV).value).Z;
double X = random.NextDouble();
double Y = .5 - (X / 2);
double Z = ZTransformer.ZTransformGivenProbability(Y);
//obfuscate X
((LocationValue)((DetectedAttributeValue)targetDV).value).X = (double)(Z * confidence + x);
//obfuscate Y
((LocationValue)((DetectedAttributeValue)targetDV).value).Y = (double)(Z * confidence + y);
//obfuscate Z
((LocationValue)((DetectedAttributeValue)targetDV).value).Z = (double)(Z * confidence + z);
//exit
targetDV.stdDev = GetConfidence(Y) * 100;
}
private static void ObfuscateVelocityValue(ref DetectedAttributeValue targetDV, ref Random random)
{
double confidence = targetDV.stdDev;
double vx = ((VelocityValue)((DetectedAttributeValue)targetDV).value).VX;
double vy = ((VelocityValue)((DetectedAttributeValue)targetDV).value).VY;
double vz = ((VelocityValue)((DetectedAttributeValue)targetDV).value).VZ;
double X = random.NextDouble();
double Y = .5 - (X / 2);
double Z = ZTransformer.ZTransformGivenProbability(Y);
//double area = (double)(random.Next((int)(Z * 10), (int)(Z * -10)) / 10.0);
//obfuscate VX
((VelocityValue)((DetectedAttributeValue)targetDV).value).VX = (double)(Z * confidence + vx);
//obfuscate VY
((VelocityValue)((DetectedAttributeValue)targetDV).value).VY = (double)(Z * confidence + vy);
//obfuscate VZ
((VelocityValue)((DetectedAttributeValue)targetDV).value).VZ = (double)(Z * confidence + vz);
//exit
targetDV.stdDev = GetConfidence(Y) * 100;
}
private static void ObfuscateStringValue(ref DetectedAttributeValue targetDV, ref Random random)
{
double confidence = targetDV.stdDev;
string strVal = ((StringValue)((DetectedAttributeValue)targetDV).value).value;
double X = random.NextDouble();
double Y = .5 - (X / 2);
double Z = ZTransformer.ZTransformGivenProbability(Y);
int strLen = strVal.Length;
strLen = (int)Math.Round((Z * confidence) + strLen, 0);
char[] str;
if (strLen <= strVal.Length)
{
str = strVal.ToCharArray(0, strLen);
}
else
{
for (int b = strVal.Length; b < strLen; b++)
{
strVal += Convert.ToChar(random.Next(49, 122));
}
str = strVal.ToCharArray();
}
StringBuilder sb = new StringBuilder();
for (int a = 0; a < strLen; a++)
{
int asciiVal = Convert.ToInt32(str[a]);
asciiVal = (int)Math.Round((ZTransformer.ZTransformGivenProbability(.5 - (random.NextDouble() / 2)) * confidence) + asciiVal, 0);
//str[a] = Convert.ToChar(asciiVal);
sb.Append(Convert.ToChar(asciiVal));
}
//((StringValue)((DetectedAttributeValue)targetDV).attribute).value = str.ToString();
((StringValue)((DetectedAttributeValue)targetDV).value).value = sb.ToString();
targetDV.stdDev = GetConfidence(Y) * 100;
}
