13. A method for information source alignment, the method comprising: generating, by a computer, a source category hierarchy tree for a source class in a first information source and a target category hierarchy tree for a target class in a second information source, wherein the source and target category hierarchy trees are constructed from a class hierarchy of a knowledge source; determining a similarity between the source and target classes by comparing the source and target category hierarchy trees, and identifying common nodes between the source and target category hierarchy trees for calculating a class-similarity value based on the category hierarchy tree comparison; determining contextual similarity between the source and target classes by determining a similarity between superclasses of the source and target classes, the superclasses being ascertained from the respective first and second information sources, and determining a number of superclasses of the source and target classes that are supported by the source and target category hierarchy trees; and determining an alignment between the source and target classes based on the comparison of the source and target category hierarchy trees, and based on the determined contextual similarity.
13. A method for information source alignment, the method comprising: generating, by a computer, a source category hierarchy tree for a source class in a first information source and a target category hierarchy tree for a target class in a second information source, wherein the source and target category hierarchy trees are constructed from a class hierarchy of a knowledge source; determining a similarity between the source and target classes by comparing the source and target category hierarchy trees, and identifying common nodes between the source and target category hierarchy trees for calculating a class-similarity value based on the category hierarchy tree comparison; determining contextual similarity between the source and target classes by determining a similarity between superclasses of the source and target classes, the superclasses being ascertained from the respective first and second information sources, and determining a number of superclasses of the source and target classes that are supported by the source and target category hierarchy trees; and determining an alignment between the source and target classes based on the comparison of the source and target category hierarchy trees, and based on the determined contextual similarity. 15. The method of claim 13 , wherein the first and second information sources are respectively source and target ontologies.