Mining Weighted Frequent Regular Patterns in Transactional Databases

1. What is weighted frequent regular pattern mining?

Weighted frequent regular pattern mining aims to discover all interesting patterns in a transactional database that have weightedsupport no less than the user-specified weighted minimum support (minWS) constraint and regularity no greater than the user-specified maximum regularity (regularity). The minWS controls the minimum number of transactions that a pattern must appear in a database. The regularity controls the minimum weight of item.

Reference: K. Klangwisan and K. Amphawan, “Mining weighted-frequent-regular itemsets from transactional database,” 2017 9th International Conference on Knowledge and Smart Technology (KST), Chonburi, Thailand, 2017, pp. 66-71, doi: 10.1109/KST.2017.7886090.

2. What is the temporal database?

A temporal database is a collection of transactions at a particular timestamp, where each transaction contains a timestamp and a set of items.
A hypothetical temporal database containing the items a, b, c, d, e, f, and g as shown below

tid	Transactions
1	a b c d
2	c e f
3	a b e f g
4	a b c f g
5	d e g
6	a b c e g
7	a b c e
8	a b d e
9	b c e
10	a e g

Note: Duplicate items must not exist in a transaction.

3. What is acceptable format of a transactional databases in PAMI

Each row in a transactional database must contain only items. The frequent pattern mining algorithms in PAMI implicitly assume the row number of a transaction as its transactional-identifier to reduce storage and processing costs. A sample transactional database, say sample.txt, is provided below.

1 a b c d
2 c e f
3 a b e f g
4 a b c f g
5 d e g
6 a b c e g
7 a b c e
8 a b d e
9 b c e
10 a e g

4. What is the Weighted database?

A weight database is a collection of items with their weights.
A hypothetical weight database, say WFRIWeightSample.txt, containing the items a, b, c, d, e, f, and g as shown below

a 0.60
b 0.50
c 0.35
d 0.45
e 0.45
f 0.3
g 0.4

5. Understanding the statisctics of database

To understand about the database. The below code will give the detail about the transactional database.

• Total number of transactions (Database size)
• Total number of unique items in database
• Minimum lenth of transaction that existed in database
• Average length of all transactions that exists in database
• Maximum length of transaction that existed in database
• Standard deviation of transaction length
• Variance in transaction length
• Sparsity of database

The below sample code prints the statistical details of a database.

import PAMI.extras.dbStats.TemporalDatabase as stats

obj = stats.TemporalDatabase('WFRISample.txt', ' ')
obj.run()
obj.printStats() 

Database size : 10
Number of items : 7
Minimum Transaction Size : 3
Average Transaction Size : 4.0
Maximum Transaction Size : 5
Minimum period : 1
Average period : 1.0
Maximum period : 1
Standard Deviation Transaction Size : 0.8944271909999159
Variance : 0.8888888888888888
Sparsity : 0.44285714285714284

The input parameters to a weighted frequent regular pattern mining algorithm are:

• Temporal database
  Acceptable formats:

  • String : E.g., ‘temporalDatabase.txt’
  • URL : E.g., https://u-aizu.ac.jp/~udayrage/datasets/temporalDatabases/temporal_T10I4D100K.csv
  • DataFrame with the header titled with ‘TS’ and ‘Transactions’

• minWS
  specified in

  • count (beween 0 to length of a database) or
  • [0, 1]

• regularity
  specified in

  • count (beween 0 to length of a database) or
  • [0, 1]

• seperator
  default seperator is ‘\t’ (tab space)

5. How to store the output of a weighted frequent regular pattern mining algorithm?

The patterns discovered by a weighted frequent regular pattern mining algorithm can be saved into a file or a data frame.

6. How to run the weighted frequent regular pattern mining algorithms in a terminal?

• Download the PAMI source code from github.
• Unzip the PAMI source code folder and enter into weighted frequent regular pattern folder.
• Enter into weightedFrequentRegularPattern folder
• Enter into a specific folder and execute the following command on terminal.

syntax: python3 algorithmName.py <path to the input file> <path to the output file> <path to the weight file> <minWS> <regularity> <seperator>

7. Sample command to execute the WFRIM code in weightedFrequentRegularPattern folder

Example: python3 WFRIM.py inputFile.txt outputFile.txt weightSample.txt 3 2 ' '

8. How to execute a weighted frequent regular pattern mining algorithm in a Jupyter Notebook?

• Install the PAMI package from the PYPI repository by executing the following command: pip3 install PAMI
• Run the below sample code by making necessary changes

from PAMI.weightedFrequentRegularPattern.basic import WFRIMiner as alg

iFile = 'WFRISample.txt'  #specify the input transactional database <br>
wFile = 'WFRIWeightSample.txt'  #specify the input transactional database <br>
minWS = 2  #specify the minSupvalue <br>
regularity = 3    #specify the minWeight value <br>
seperator = ' ' #specify the seperator. Default seperator is tab space. <br>
oFile = 'weightedFrequentRegularPatterns.txt'   #specify the output file name<br>

obj = alg.WFRIMiner(iFile, wFile, minWS, regularity, seperator) #initialize the algorithm <br>
obj.mine()                       #start the mining process <br>
obj.save(oFile)               #store the patterns in file <br>
df = obj.getPatternsAsDataFrame()     #Get the patterns discovered into a dataframe <br>
obj.printResults()                      #Print the stats of mining process

Weighted Frequent Regular patterns were generated successfully using WFRIM algorithm
Total number of  Weighted Frequent Regular Patterns: 9
Total Memory in USS: 99409920
Total Memory in RSS 140251136
Total ExecutionTime in ms: 0.00046825408935546875

The weightedFrequentRegularPatterns.txt file contains the following patterns (format: pattern:support): !cat weightedPatterns.txt

!cat weightedFrequentRegularPatterns.txt

c:[6, 2, 2.0999999999999996] 
c	b:[5, 3, 2.125] 
a:[7, 2, 4.2] 
a	e:[5, 3, 2.625] 
a	e	b:[5, 3, 2.5833333333333335] 
a	b:[7, 2, 3.8500000000000005] 
e:[8, 2, 3.6] 
e	b:[6, 3, 2.8499999999999996] 
b:[8, 2, 4.0] 

The dataframe containing the patterns is shown below:

df

	Patterns	Support
0	c	[6, 2, 2.0999999999999996]
1	c b	[5, 3, 2.125]
2	a	[7, 2, 4.2]
3	a e	[5, 3, 2.625]
4	a e b	[5, 3, 2.5833333333333335]
5	a b	[7, 2, 3.8500000000000005]
6	e	[8, 2, 3.6]
7	e b	[6, 3, 2.8499999999999996]
8	b	[8, 2, 4.0]