高级检索

    基于对象相关性的全监督和直推式排序算法

    Supervised and Transductive Ranking Algorithms with Relational Objects

    • 摘要: 在信息检索和机器学习领域,大部分排序学习方法假设查询中的各个对象均满足独立同分布.虽然该假设简化了排序问题,却未能利用目标对象之间隐藏的相关性信息.在全监督排序和直推式排序2个问题中分别提出了新的方法,充分地利用了对象间的关系.在全监督排序问题中,将对象相关性映射为RBF Kernel,作为约束项加入优化目标,使得优化过程中越相似的对象打分越接近,即全局一致性思想.在直推式排序问题中,利用对象相关性将每个查询映射为图结构,设计了新的基于图结构的查询相似度度量,使得优化过程中越相似的查询,该查询内的对象对预测查询的影响越大.实验结果表明,加入对象之间的相关性提升了全监督排序算法和直推式排序算法的性能.

       

      Abstract: Learning to rank task is a learning process which aims at obtaining a ranking model through machine learning techniques for ranking objects. It has become one of the hot research topics in both information retrieval and machine learning communities recently. In information retrieval and machine learning fields, most of existing learning to rank approaches assume that all objects in a given query are independently and identically distributed. Although this assumption simplifies the ranking problems, the implicit interconnections among objects for each query are not exploited in the learning process. Actually, the information of the implicit interconnections can help improve the ranking performance of the ranking algorithms. In this paper, new methods are proposed in supervised ranking and transductive ranking problems to utilize the latent interconnections. In supervised ranking, a graph based ranking framework is proposed, which takes advantage of global consistency that similar objects deserve similar scores. In transductive ranking, a new query similarity measure by the interconnections among the objects is proposed, such that the more representative objects are, the more importance weighting are obtained for them. Finally, this paper validates the usefulness of relational information among objects by improving the performances of RankSVM-primal algorithm and transductive ranking algorithm in the experiments.

       

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