4. An apparatus comprising: an input; a receiver; and a controller which operates with the input and the receiver to: (a) receive a document which includes: (i) an internal structure including: (A) a first element having a first active value; and (B) a second element having a second active value; and (ii) first characteristic information; (b) diffuse the first active value and the second active value; (c) using the diffused first active value and the diffused second active value, extract the first characteristic information having post-diffusion active values larger than pre-set threshold values; (d) enable a user to form a plurality of classification items which have second characteristic information; (e) using the formed plurality of classification items, prepare a classification model; (f) determine a degree of interrelation between the extracted first characteristic information and the second characteristic information; (g) determine whether the determined degree exceeds a threshold value; (h) in response to the determined degree exceeding the threshold value, using the prepared classification model, automatically classify the document into one of the formed plurality of classification items; (i) innovate the classification model based on the classification of the document if the document is classified into one of the plurality of classification items, wherein a weight is imparted to each element based on the internal structure of said document; and (j) extract an element having the weight larger than a pre-set value.
4. An apparatus comprising: an input; a receiver; and a controller which operates with the input and the receiver to: (a) receive a document which includes: (i) an internal structure including: (A) a first element having a first active value; and (B) a second element having a second active value; and (ii) first characteristic information; (b) diffuse the first active value and the second active value; (c) using the diffused first active value and the diffused second active value, extract the first characteristic information having post-diffusion active values larger than pre-set threshold values; (d) enable a user to form a plurality of classification items which have second characteristic information; (e) using the formed plurality of classification items, prepare a classification model; (f) determine a degree of interrelation between the extracted first characteristic information and the second characteristic information; (g) determine whether the determined degree exceeds a threshold value; (h) in response to the determined degree exceeding the threshold value, using the prepared classification model, automatically classify the document into one of the formed plurality of classification items; (i) innovate the classification model based on the classification of the document if the document is classified into one of the plurality of classification items, wherein a weight is imparted to each element based on the internal structure of said document; and (j) extract an element having the weight larger than a pre-set value. 5. The apparatus of claim 4 , wherein the controller operates with the receiver to: (a) receive a plurality of documents; and (b) extract the characteristic information representing characteristics of each received document.