Patent ID: 11960521
Assignee: nan
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 3:
4. The text classification method based on feature selection according to claim 1, wherein TF-IWF algorithm is used to give the weights to the extracted feature entries, wherein a word frequency TF refers to a frequency that a certain entry ti appears in the document dj, which is generally normalized, and a calculation process is as follows:, TF
   ij
  
  =
  
   
    n
    
     i
     ,
     j
    
   
   
    
     ∑
     
        
      k
     
    
    
     n
     
      k
      ,
      j
     
    
   
  
 

where ni,j represents the number of occurrences of the entry ti in the document dj, and Σknk,j represents the total number of occurrences of all entries in the document dj;
an inverse word frequency IWF refers to the reciprocal of the proportion of the total number of words to the total number of documents, and a calculation process is as follows:, IWF
   i
  
  =
  
   log
   ⁢
   
    
     
      ∑
      
         
       m
      
     
     
      
       n
       i
      
      ⁢
      
       t
       i
      
     
    
    
     
      n
      i
     
     ⁢
     
      t
      i
     
    
   
  
 

where Σmniti represents the total number of entries ti appearing in all documents in the category m, and niti represents the number of entries ti appearing in the document dj;
the TF-IWF value Wi,j is obtained by multiplying the value of the word frequency TFij by the value of the inverse word frequency IWFi, and the calculation formula is as follows:

Wi,j=TFij×IWFi.