论文标题

共识学习的基于内核的广义中值计算

Kernel-Based Generalized Median Computation for Consensus Learning

论文作者

Nienkötter, Andreas, Jiang, Xiaoyi

论文摘要

从一组给定对象中计算共识对象是机器学习和模式识别的核心问题。一种流行的方法是使用广义中位数将其作为优化问题。先前的方法(例如原型和远距离嵌入方法)将对象转换为向量空间,解决该空间中的广义中值问题,然后倒变回原始空间。这两种方法都成功地应用于广泛的对象域,其中广义的中值问题具有固有的高计算复杂性(通常为$ \ Mathcal {np} $ - 硬),因此需要近似解决方案。以前,在计算中使用了显式嵌入方法,这通常不反映对象之间的空间关系。在这项工作中,我们介绍了一个基于内核的广义中间框架,该框架适用于积极的确定和无限核。该框架计算对象与其在内核空间中的广义中位数之间的关系,而无需显式嵌入。我们表明,与使用易于计算的内核相比,对象之间的空间关系比在显式矢量空间中更准确地表示,并且在三个不同域的数据集中证明了广义中值计算的出色性能。我们的工作产生的软件工具箱可公开使用,以鼓励其他研究人员探索广义的中位数计算和应用。

Computing a consensus object from a set of given objects is a core problem in machine learning and pattern recognition. One popular approach is to formulate it as an optimization problem using the generalized median. Previous methods like the Prototype and Distance-Preserving Embedding methods transform objects into a vector space, solve the generalized median problem in this space, and inversely transform back into the original space. Both of these methods have been successfully applied to a wide range of object domains, where the generalized median problem has inherent high computational complexity (typically $\mathcal{NP}$-hard) and therefore approximate solutions are required. Previously, explicit embedding methods were used in the computation, which often do not reflect the spatial relationship between objects exactly. In this work we introduce a kernel-based generalized median framework that is applicable to both positive definite and indefinite kernels. This framework computes the relationship between objects and its generalized median in kernel space, without the need of an explicit embedding. We show that the spatial relationship between objects is more accurately represented in kernel space than in an explicit vector space using easy-to-compute kernels, and demonstrate superior performance of generalized median computation on datasets of three different domains. A software toolbox resulting from our work is made publicly available to encourage other researchers to explore the generalized median computation and applications.

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