OurMethodPGP.java

package happy.research.pgp;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

public class OurMethodPGP extends AbstractPGP
{
	@Override
	protected Performance firePerformanceTest(final List<PGPNode> nodes)
	{
		int numNodes = nodes.size();
		int coversCount[] = new int[numNodes];
		double coverages[] = new double[numNodes];
		double accuracies[] = new double[numNodes];
		double distances[] = new double[numNodes];
		
		for (int i = 0; i < numNodes; i++)
		{
			PGPNode entity = nodes.get(i);
			Map<PGPNode, Double> tnsAll_positive = new HashMap<>(numNodes * 2);
			Map<PGPNode, Double> tnsAll_negative = new HashMap<>(numNodes * 2);
			Map<PGPNode, CertificateType> tnsAll_combined = new HashMap<>(numNodes * 2);
			Map<PGPNode, Double> tnsAll_confidence = new HashMap<>(numNodes * 2);
			// process raw data
			for (Entry<PGPNode, TrustType> entry : entity.getTns().entrySet())
			{
				PGPNode tn = entry.getKey();
				TrustType tt = entry.getValue();
				if (tn == entity) continue;
				// TrustType tt=entry.getValue();
				for (Entry<PGPNode, TrustType> tn_entry : tn.getNeighborus().entrySet())
				{
					PGPNode tn_tn = tn_entry.getKey();
					CertificateType tn_ct = tn_tn.getSigners().get(tn);
					
					// Due to some tns directly predefined without signing
					// so tn_ct == null is possible
					if (tn_ct == null) continue;

					if (tnsAll_positive.containsKey(tn_tn))
					{
						// combine together using majority method
						// problem: what if positive no. = negative no.?
						
						if (tn_ct == CertificateType.VALID)
						{
							tnsAll_positive.put(tn_tn,	tnsAll_positive.get(tn_tn).doubleValue() 
												+ tn_ct.getInherentValue() * tt.getTrustValue());

						} else if (tn_ct == CertificateType.INVALID)
						{
							tnsAll_negative.put(tn_tn,	tnsAll_negative.get(tn_tn).doubleValue() 
												+ tn_ct.getInherentValue() * tt.getTrustValue());
						}

					} else
					{
						// make sure positive and negative set have same size
						if (tn_ct == CertificateType.VALID)
						{
							tnsAll_positive.put(tn_tn, tn_ct.getInherentValue() * tt.getTrustValue());
							tnsAll_negative.put(tn_tn, 0.0);
						} else if (tn_ct == CertificateType.INVALID)
						{
							tnsAll_positive.put(tn_tn, 0.0);
							tnsAll_negative.put(tn_tn, tn_ct.getInherentValue() * tt.getTrustValue());
						}
					}
				}
			}
			// compute combined vector and confidence
			for (Entry<PGPNode, Double> entry_positive : tnsAll_positive.entrySet())
			{
				PGPNode node = entry_positive.getKey();
				double r = Math.abs(entry_positive.getValue().doubleValue());
				double s = Math.abs(tnsAll_negative.get(node).doubleValue());
				try
				{
					double confidence = calculateCertainty(r, s);
					// logger.info("r = " + r + " , s = " + s + ", confidence = " + confidence);
					// only nodes with confidence>threshold will be used latter
					if (confidence >= AbstractPGP.CONFIDENCE_THRESHOLD && r > s)
					{
						tnsAll_combined.put(node, CertificateType.VALID);
						tnsAll_confidence.put(node, new Double(confidence));
					} else if (confidence >= AbstractPGP.CONFIDENCE_THRESHOLD && r <= s)
					{
						tnsAll_combined.put(node, CertificateType.INVALID);
						tnsAll_confidence.put(node, new Double(confidence));
					}
				} catch (Exception e)
				{
					e.printStackTrace();
				}
			}
			// compute the similar nodes
			if (tnsAll_combined.size() > 0)
			{
				entity.getNns().clear();
				for (int j = 0; j < numNodes; j++)
				{
					if (j == i) continue;// self
					PGPNode candidate = nodes.get(j);
					if (entity.getTns().containsKey(candidate)) continue; // tns
						
					// test if candidate is a candidate
					// double sum_rx = 0.0, sum_ry = 0.0;
					int size = tnsAll_combined.size();
					int[] rxs = new int[size];
					int[] rys = new int[size];
					int index = 0;
					for (Entry<PGPNode, CertificateType> entry : tnsAll_combined.entrySet())
					{
						PGPNode node = entry.getKey();
						if (candidate.getNeighborus().containsKey(node) && node.getSigners().get(candidate) != null)
						{
							rxs[index] = entry.getValue().getInherentValue();
							rys[index] = node.getSigners().get(candidate).getInherentValue();

							// sum_rx += rxs[index];
							// sum_ry += rys[index];
							index++;
						}
					}
					if (index <= size * AbstractPGP.CANDIDATE_VECTOR_RATIO)
					{
						// not a candidate
						continue;
					}
					// calculate similarity
					
					// double rx = sum_rx / index;
					// double ry = sum_ry / index;
					// double similarity = evaluatePearsonSimilarity(rx, ry, rxs, rys, index);

					double similarity = evaluateCosineSimilarity(rxs, rys, index);
					// logger.info("test similarity = " + similarity);
					if (similarity >= AbstractPGP.SIMILARITY_THRESHOLD)
					{
						// nearest neighbour with trust value = similarity
						entity.getNns().put(candidate, new Double(similarity));
					}
				}
			}
			// evaluate the performance: coverage and distance
			int count_coverage = 0, accuracy_count = 0;
			for (int j = 0; j < numNodes; j++)
			{
				if (j == i) continue;
				PGPNode target = nodes.get(j);
				if (entity.getTns().containsKey(target)) continue;
				if (entity.getNns().containsKey(target)) continue;
				double positive_sum = 0.0, negative_sum = 0.0;
				int count_test = 0;
				for (Entry<PGPNode, CertificateType> entry : target.getSigners().entrySet())
				{
					PGPNode signer = entry.getKey();
					CertificateType ct = entry.getValue();
					
					if (signer == target) continue;

					if (entity.getTns().containsKey(signer))
					{
						TrustType tt = entity.getTns().get(signer);
						if (ct == CertificateType.VALID)
							positive_sum += tt.getTrustValue() * ct.getInherentValue();
						else if (ct == CertificateType.INVALID)
							negative_sum += tt.getTrustValue() * ct.getInherentValue();
						count_test++;
					} else if (entity.getNns().containsKey(signer))
					{
						double similarity = entity.getNns().get(signer);
						if (ct == CertificateType.VALID)
							positive_sum += similarity * ct.getInherentValue();
						else if (ct == CertificateType.INVALID) 
							negative_sum += similarity * ct.getInherentValue();
						count_test++;
					}
				}
				if (count_test > 0)
				{
					count_coverage++;
					double validity = (Math.abs(positive_sum) - Math.abs(negative_sum))
							/ (Math.abs(positive_sum) + Math.abs(negative_sum));
					double distance = Math.abs(validity - target.getCertificate().getInherentValue());
					distances[i] += distance;
					if (distance <= ACCURACY_THRESHOLD) accuracy_count++;
				}
			}
			coversCount[i] = count_coverage;
			int needsCoverCount = numNodes - 1 - entity.getTns().size() - entity.getNns().size();
			// logger.info("no. of entity " + i + " nearest neighbors = " +
			// entity.getNns().size());
			coverages[i] = (coversCount[i] + 0.0) / needsCoverCount;
			accuracies[i] = (accuracy_count + 0.0) / needsCoverCount;
			if (coversCount[i] > 0)
				distances[i] /= coversCount[i];
		}
		
		return calculatePerformance(AbstractPGP.OURMETHOD_PGP, coversCount, coverages, distances, accuracies);
	}

}