//针对某一个节点的不同事件可信度，计算其可信度
static IOTNodeTrustResult DeduceNodeTrustByDefault(int node, List<IOTEventTrustResult> events, float interval)
{
//将事件按照类型分类
Dictionary<IOTEventCategoryType, List<IOTEventTrustResult>> temp = new Dictionary<IOTEventCategoryType, List<IOTEventTrustResult>>();
foreach (IOTEventTrustResult e in events)
{
if (!temp.ContainsKey(e.category))
temp.Add(e.category, new List<IOTEventTrustResult>());
temp[e.category].Add(e);
}
//计算每个类型的可信度，每个类型的可信度由多次该类型的事件组成，可使用正交的方法进行推导
List<IOTEventTrustCategoryResult> combinedCategories = new List<IOTEventTrustCategoryResult>();
foreach (KeyValuePair<IOTEventCategoryType, List<IOTEventTrustResult>> pair in temp)
{
IOTEventCategoryType category = pair.Key;
List<IOTEventTrustResult> events1 = pair.Value;
IOTEventTrustCategoryResult r = CombineToCategory(node, node + "-" + category, category, events1);
combinedCategories.Add(r);
}
//分析每个类型的可信度，以及每个类型事件的频率，来推导节点的可信度
//先分析频率，更新类型的可信度
HashDSClass hashedCaterogies = new HashDSClass(IOTEventTrust.pow(IOTEventType.COUNT));
int[] confirmedCount = new int[(int)IOTEventType.COUNT];
int[] totalCount = new int[(int)IOTEventCategoryType.COUNT];
for (int i = 0; i < combinedCategories.Count; i++)
{
IOTEventTrustCategoryResult r = combinedCategories[i];
int start = IOTEventTrustResult.GetStartTypeByCategory(r.category);
int count = IOTEventTrustResult.GetCountByCategory(r.category);
totalCount[i] = r.totalEventCount;
for (int j = 0; j < count; j++)
confirmedCount[start + j] = r.confirmedEventNums[j];
MergeToHashDS(hashedCaterogies, r);
}
hashedCaterogies.Normalize();
IOTNodeTrustResult nodeTrust = DeduceNodeTrustByCategories(node, combinedCategories[0].app, hashedCaterogies, confirmedCount, totalCount);
return nodeTrust;
}
static void MergeToHashDS(HashDSClass ds, IOTEventTrustCategoryResult r)
{
int start = IOTEventTrustResult.GetStartTypeByCategory(r.category);
for (int i = start; i < r.ds.length; i++)
ds.SetM(i, r.ds.m[i]);
}
//根据节点事件的类型来推导节点的可信度
static IOTNodeTrustResult DeduceNodeTrustByCategories(int node, int app, HashDSClass hashedCaterogies, int[] confirmedCount, int[] totalCount)
{
IOTGlobal global = (IOTGlobal)IOTGlobal.getInstance();
IOTNodeTrustResult nodeTrust = new IOTNodeTrustResult(node, app);
double c1 = DSClass.OR(hashedCaterogies.GetM(IOTEventTrust.pow(IOTEventType.NotDropPacket)),
hashedCaterogies.GetM(IOTEventTrust.pow(IOTEventType.NotModifyPacket))); //Normal
double c2 = DSClass.OR(hashedCaterogies.GetM(IOTEventTrust.pow(IOTEventType.NotDropPacketButNotReceivePacket)),
hashedCaterogies.GetM(IOTEventTrust.pow(IOTEventType.ModifyPacketDueToNodeFaulty))); //Node faulty
double c3 = DSClass.OR(hashedCaterogies.GetM(IOTEventTrust.pow(IOTEventType.DropPacketDueToBandwith)),
hashedCaterogies.GetM(IOTEventTrust.pow(IOTEventType.NotModifyPacketButNetworkFaulty))); //Env faulty
double c4 = DSClass.OR(hashedCaterogies.GetM(IOTEventTrust.pow(IOTEventType.DropPacketMaliciously)),
hashedCaterogies.GetM(IOTEventTrust.pow(IOTEventType.ModifyPacketMaliciously))); //Maliciously
DSClass ds = new DSClass(pow(IOTNodeType.COUNT));
ds.SetM(DSClass.pow((int)IOTNodeType.NORMAL), c1);
ds.SetM(DSClass.pow((int)IOTNodeType.NODE_FAULTY), c2);
ds.SetM(DSClass.pow((int)IOTNodeType.ENV_FAULTY), c3);
ds.SetM(DSClass.pow((int)IOTNodeType.MALICIOUS), c4);
ds.Normalize();
ds.Cal();
nodeTrust.ds = ds;
for (int i = 0; i < totalCount.Length; i++)
{
IOTEventCategoryType categoryType = (IOTEventCategoryType)i;
int start = IOTEventTrustResult.GetStartTypeByCategory(categoryType);
int count = IOTEventTrustResult.GetCountByCategory(categoryType);
for (int j = 0; j < count; j++)
{
int iType = start + j;
IOTEventType eventType = (IOTEventType)iType;
int confirmed = confirmedCount[iType];
if (!nodeTypeMapping.ContainsKey(eventType))
throw new Exception("No such a event type defined");
if (totalCount[i] == 0)
continue;
nodeTrust.confirmed[(int)nodeTypeMapping[eventType]] += confirmed;
if (ds.b[DSClass.pow(iType)] > global.BeliefThrehold && ds.p[DSClass.pow(iType)] > global.PlausibilityThrehold)
nodeTrust.confirmedRate[iType] = (double)confirmed / totalCount[i];
}
}
return nodeTrust;
}
