Patent ID: 8280829

Claim:
A method implemented on at least one machine each of which has at least one processor, storage, and a communication platform connected to a network, the method comprising: accessing a ranking model and an objective function of the ranking model, wherein given a reference and a set of objects, the ranking model ranks the set of objects with respect to the reference, and the objective function represents erroneous predictions made by the ranking model; accessing one or more preference pairs of objects, wherein for each of the preference pairs of objects comprising a first object and a second object: the first object and the second object are obtained in response to a particular one of one or more references, there is a preference between the first object and the second object with respect to the particular reference, the first object has a first feature vector comprising one or more first feature values, wherein each of the first feature values characterizes a property of the first object, the particular reference, or the first object and the particular reference together, and the second object has a second feature vector comprising one or more second feature values, wherein each of the second feature values characterizes a property of the second object, the particular reference, or the second object and the particular reference together; and training the ranking model by minimizing the objective function using the preference pairs of objects, wherein for each of the preference pairs of objects, a difference between the first feature vector of the first object and the second feature vector of the second object is not calculated.