20. An electronic device for comparing documents, the electronic device comprising: a memory; and a processor communicatively coupled to the memory, the processor configured to: associate a respective weight with each of a plurality of information types including text-based information, graphical information, audio information, or video information; identify, for each of the first document and the second document, one or more segments each corresponding to one of the plurality of information types; and estimate a similarity value between the first document and the second document, by comparing each segment of the first document with a segment of the second document that correspond to a same information type, wherein the similarity value is based on a distance, in a semantic hierarchy, between a first semantic class associated with the first document and a common ancestor, in the semantic hierarchy, of the first semantic class and a second semantic class associated with a second document; and combine results of the comparison based on the respective associated weights.
20. An electronic device for comparing documents, the electronic device comprising: a memory; and a processor communicatively coupled to the memory, the processor configured to: associate a respective weight with each of a plurality of information types including text-based information, graphical information, audio information, or video information; identify, for each of the first document and the second document, one or more segments each corresponding to one of the plurality of information types; and estimate a similarity value between the first document and the second document, by comparing each segment of the first document with a segment of the second document that correspond to a same information type, wherein the similarity value is based on a distance, in a semantic hierarchy, between a first semantic class associated with the first document and a common ancestor, in the semantic hierarchy, of the first semantic class and a second semantic class associated with a second document; and combine results of the comparison based on the respective associated weights. 21. The electronic device of claim 20 , wherein the method further comprises: construct a first language-independent semantic structure (LISS) for a first sentence of the first document; and identify the first semantic class using the language-independent semantic structure.