Most work in neural networks focuses on estimating the conditional mean of a continuous response variable given a set of covariates.In this article, we consider estimating the conditional distribution function using neural networks for both censored and uncensored data. The algorithm is built upon the data structure particularly constructed for the Cox regression with time-dependent covariates. Without imposing any model assumption, we consider a loss function that is based on the full likelihood where the conditional hazard function is the only unknown nonparametric parameter, for which unconstraint optimization methods can be applied. Through simulation studies, we show the proposed method possesses desirable performance, whereas the partial likelihood method and the traditional neural networks with $L_2$ loss yield biased estimates when model assumptions are violated. We further illustrate the proposed method with several real-world data sets. The implementation of the proposed methods is made available at https://github.com/bingqing0729/NNCDE.
翻译:在神经网络中,大多数工作的重点是根据一组共变数来估计连续响应变量的有条件平均值。 在本条中,我们考虑利用神经网络来估计有条件分布功能,用于检查和未审查的数据。算法基于数据结构,特别是Cox回归的数据结构,有时间的共变数。在不强加任何模型假设的情况下,我们考虑一种损失功能,这种损失功能所依据的是有条件危险功能是唯一未知的非参数的全部可能性,可以对其适用不限制的优化方法。通过模拟研究,我们展示了拟议方法具有理想性能,而部分可能性方法和传统的以L_2$损失为单位的神经网络在模型假设被违反时会产生偏差估计。我们进一步用几个真实世界数据集来说明拟议方法。拟议方法的实施可在https://github.com/bingqing0729/NNCDE查阅。