22. A non-transitory computer-readable storage medium having recorded thereon a software program utilized by a computer in the generation of training data used for creating characteristic expression extraction rules, the software program comprising instructions that direct the computer to perform the steps of: assigning labels to training data candidates by referring to an incomplete ground truth corpus, clustering a plurality of training data candidates including annotation errors and assigned labels indicating annotation classes based on feature values containing respective context information and, by referring to each cluster obtained using the clustering results in said clustering step, obtaining the distribution of the labels of the training data candidates within the cluster, identifying training data candidates that meet a preset condition based on the obtained distributions, and generating training data using the identified training data candidates, wherein said context information is individual words, modifying or modified phrases in the vicinity of the units that constitute the training data candidates or training data, and the training data is utilized in the creation of characteristic expression extraction rules.
22. A non-transitory computer-readable storage medium having recorded thereon a software program utilized by a computer in the generation of training data used for creating characteristic expression extraction rules, the software program comprising instructions that direct the computer to perform the steps of: assigning labels to training data candidates by referring to an incomplete ground truth corpus, clustering a plurality of training data candidates including annotation errors and assigned labels indicating annotation classes based on feature values containing respective context information and, by referring to each cluster obtained using the clustering results in said clustering step, obtaining the distribution of the labels of the training data candidates within the cluster, identifying training data candidates that meet a preset condition based on the obtained distributions, and generating training data using the identified training data candidates, wherein said context information is individual words, modifying or modified phrases in the vicinity of the units that constitute the training data candidates or training data, and the training data is utilized in the creation of characteristic expression extraction rules. 28. The non-transitory computer-readable storage medium according to claim 22 , wherein in Step (b), a new feature value is appended to the training data candidates used as the training data.