The results using IPSJ keywords are not stable as will be shown in Section 5.2.2., however, the results are consistent with the characteristics of the three subfields, CS and IE include standard and traditional subfields, thus they are represented by low-expertise, but standard keywords in information sciences, but FR includes many new topics, thus they are not represented by these types of standard keywords either.
fR includes various topics, thus it is not represented by any type of keywords lists.