18. The process of claim 17 , said aligning comprising: projecting each target centroid to the pivot vocabulary; creating a cross-domain similarity graph comprising a first set of vertices S and a second set of vertices T, wherein each vertex of the first set S corresponds to each source centroid, wherein each vertex of the second set T corresponds to said each target centroid, and wherein a weight of a first edge between a first source centroid from the first set S and a first target centroid from the second set T represents a respective cross-domain similarity of the first target centroid to the first source centroid; computing a maximum-weighted bipartite match over the cross-domain similarity graph such that the maximum-weighted bipartite match represents an alignment that has a largest sum of all cross-domain similarities between the source centroids in the first set S and the target centroids in the second set T, wherein a match comprises at least one edge of the cross-domain similarity graph, and wherein a weight of the match is the sum of weights of all edges in the match; updating target centroids in the maximum-weighted bipartite match by a cross-domain update rule that is respectively associated with each target centroid in the maximum-weighted bipartite match such that a respective divergence between said each source centroid and updated target centroids is reduced; and reassigning said at least one target data item to a nearest target centroid among all target centroids from said updating.
19. The process of claim 18 , wherein the cross-domain update rule that is respectively associated with said each target centroid for an updated target centroid C i t is C _ i t = α ⁢ ∑ t i ∈ C i t ⁢ t i + ( 1 - α ) ⁢ ∑ j ⁢ δ x ⁡ ( C i t , C j s ) ⁢ C _ j s α ⁢  C i t  + ( 1 - α ) ⁢  C i t  ⁢ ∑ j ⁢ δ x ⁡ ( C i t , C j s ) , wherein t i represents said at least one target data item, wherein αΣ t i εC i t t i quantifies a target centroid convergence for all target data item such that an updated target centroid C i t converges toward a center of a respective target cluster corresponds to said each target centroid, wherein (1−α)Σ j δ x (C i t , C j s ) C j s quantifies the cross-domain alignment of the target centroids to the source centroids C j s , and wherein a relevance parameter α represents how relevant the source clusters C j s and the target clusters C i t and how the target centroid convergence and the cross-domain alignment are traded off in said updating.