PHUIMUS: A Potential High Utility Itemsets Mining Algorithm Based on Stream Data with Uncertainty

Algorithm 1

Description of PHUIMUS algorithm.

Input: A transaction uncertain data stream, utility table, for current window ,

   number of batches in a window (), number of transactions in a batch ().

Output: PHUIs for the current window

Step 1. Create a global table H to keep the items in the lexicographic order;

Step 2. Create the root of TWPUS-tree and initialize it as NULL;

Step 3. Create a global PUS-list to keep potential utility of items and transactions, whose number of row is

   , and number of column is equal to the number of items in utility table;

   while a new batch arrives do

    for transaction in batch do

Step 4.  Sort the items of in the lexicographic order;

Step 5.  Calculate potential utility of items and transactions, inserting them into PUS-list;

Step 6.  Update twpu value in the header table H;

Step 7.   If then

     If the item in isn’t exist in the TWPUS-tree then

      Create a new node for it, which consists by the item’s name and twpu counter array

                ;

     else

      Insert twpu value of to its twpu counter array’s th position, denoted as

              ;

     End if

Step 8.  else

     Perform one time left shift operation for all the twpu counter arrays;

     Remove the transactions of and insert transactions of in the PUS-list;

     Update them in the header table H;

     Delete the nodes that all the values in their corresponding twpu counter array are zero;

     If the item in isn’t exist in the TWPUS-tree then

      Create a new node for it, which consists by the item’s name and twpu counter array

                ;

     else

      Insert twpu value of to its twpu counter array’s rightest position, denoted as

              ;

     End if

     End if

    End for

    for each window do

     for each item from the bottom of H do

Step 9.   Add itemset to the global candidate list;

Step 10.   Create Prefix tree with its header table for item ;

Step 11.   For each item of do

       If then

       Delete from and to create conditional tree and its header table ;

       End if

      End for

Step 12.   Create all the candidate itemsets from , represented by ;

Step 13.   Add to the global candidate list;

Step 14.   Calculate PHUIs from the global candidate list by PUS-list;

Step 15.   Delete current bottom item of H, when it becomes NULL, jump out current loop;

     End for

    End for

    End while