2. The apparatus of claim 1 , wherein the analysis unit comprises: a topic segment constructor configured to construct at least one topic segment comprising at least one candidate topic using the log information collected from the information collection unit; an extractor configured to extract a sentence constituent element for constituting a sentence from each topic segment; a topic decider configured to decide a topic for each topic segment based on a frequency of occurrence of a topic according to the sentence constituent element extracted in the extractor; and an episode decider configured to select one topic segment for a reference time based on the frequency of occurrence of a topic comprised in each topic segment.
2. The apparatus of claim 1 , wherein the analysis unit comprises: a topic segment constructor configured to construct at least one topic segment comprising at least one candidate topic using the log information collected from the information collection unit; an extractor configured to extract a sentence constituent element for constituting a sentence from each topic segment; a topic decider configured to decide a topic for each topic segment based on a frequency of occurrence of a topic according to the sentence constituent element extracted in the extractor; and an episode decider configured to select one topic segment for a reference time based on the frequency of occurrence of a topic comprised in each topic segment. 5. The apparatus of claim 2 , wherein the extractor is further configured to update the frequency of occurrence of a topic for a sentence constituent element extracted from each topic segment.