7. A computer program product being tangibly stored on a non-transient machine-readable medium and comprising machine-executable instructions, the instructions, when executed on a device, causing the device to: obtain a set of candidate concepts of a surface form in a sequence of surface forms in a plaintext; determine first probabilities for the candidate concepts, a first probability indicating likelihood that the surface form represents the respective candidate concept; select one of the candidate concepts for the surface form based on the first probabilities and adjacency of the surface forms in the sequence; determine occurrence probabilities for the candidate concepts based on the first probabilities and the adjacency of the surface forms in the sequence, an occurrence probability indicating likelihood that the respective candidate concept is mentioned in the plaintext; and select one of the candidate concepts for the surface form based on the occurrence probabilities.
7. A computer program product being tangibly stored on a non-transient machine-readable medium and comprising machine-executable instructions, the instructions, when executed on a device, causing the device to: obtain a set of candidate concepts of a surface form in a sequence of surface forms in a plaintext; determine first probabilities for the candidate concepts, a first probability indicating likelihood that the surface form represents the respective candidate concept; select one of the candidate concepts for the surface form based on the first probabilities and adjacency of the surface forms in the sequence; determine occurrence probabilities for the candidate concepts based on the first probabilities and the adjacency of the surface forms in the sequence, an occurrence probability indicating likelihood that the respective candidate concept is mentioned in the plaintext; and select one of the candidate concepts for the surface form based on the occurrence probabilities. 9. The computer program product of claim 7 , wherein the instructions cause the device to: responsive to a determination that the surface form has a preceding surface form in the sequence, for each of the candidate concepts: determine second probabilities with respect to preceding candidate concepts of the preceding surface form, a second probability indicating likelihood that the candidate concept is mentioned after the respective preceding candidate concept; determine candidate occurrence probabilities based on the occurrence probabilities for the preceding candidate concepts, the first probability and the second probabilities; and select a maximal candidate occurrence probability from among the candidate occurrence probabilities as the occurrence probability.