Application of discrete-time survival methods for continuous-time survival prediction is considered. For this purpose, a scheme for discretization of continuous-time data is proposed by considering the quantiles of the estimated event-time distribution, and, for smaller data sets, it is found to be preferable over the commonly used equidistant scheme. Furthermore, two interpolation schemes for continuous-time survival estimates are explored, both of which are shown to yield improved performance compared to the discrete-time estimates. The survival methods considered are based on the likelihood for right-censored survival data, and parameterize either the probability mass function (PMF) or the discrete-time hazard rate, both with neural networks. Through simulations and study of real-world data, the hazard rate parametrization is found to perform slightly better than the parametrization of the PMF. Inspired by these investigations, a continuous-time method is proposed by assuming that the continuous-time hazard rate is piecewise constant. The method, named PC-Hazard, is found to be highly competitive with the aforementioned methods in addition to other methods for survival prediction found in the literature.

本文提出了一种应用离散时间生存方法进行连续时间生存预测的方法，并探讨了PMF和离散时间风险率的参数化两种神经网络插值方法，并通过真实和模拟数据研究表明离散时间风险率参数化方法略胜一筹。同时，也提出了一种基于假设连续时间风险率是分段恒定的连续时间方法，并发现该方法在生存预测方面与其他方法相比非常有竞争力。

使用神经网络进行连续和离散时间的生存预测