2022年7月13日 · 在 Cox比例风险回归模型 (Cox Proportional Hazard Regression Model)——R软件实现 一文中，采用设立卡氏评分与时间的交互项进行数据分析，与年龄、性别一起建立含时依存协变量的Cox比例风险模型。

AFT模型是对生存时间进行建模的。 它常使用在工业领域，如研究零件寿命受温度的影响，因此把生存时间称为失效时间（Failure Time）。 本篇目录如下： 使用 T 表示生存时间（survival time）， S (t) = P (T>t) 表示 生存函数 （survival function）。 F (t) = 1-S (t) = P (T\le t) 表示 T 的 累积分布函数 （cumulative distribution function, CDF）， f (t) = F' (t) 表示 T 的概率密度函数（density function）。

AFT模型与PH模型都是生存分析中非常常用的参数模型，其形式易于理解（分别是对hazard、Time的指数形式建模），求解比较方便（NR迭代）。 然而，参数模型依赖于较强的模型假设，当假设不满足时，其效果一般较差。 因此我们需要进一步学习非参数模型，一般来说： 非参数模型相较于参数模型更加稳健。 下一节我们将会展开来说（事实上我们将会接触到的是一个中间概念： 半参数模型）。

2016年12月15日 · 这些是用于时间变量的任意变换的位置尺度模型; 最常见的情况使用对数变换，建立加速失效时间模型。 y=TRUE, robust=FALSE, score=FALSE, ...) y变量的假设分布。"weibull", "exponential", "gaussian", "logistic","lognormal" and "loglogistic"。 可选的固定值。 如果设置<=0，scale将被估计. convergence tolerance. 因此，从上述公式我们可以得到一个重要结论：设定计算迭代误差的时候，要全面权衡物理量的绝对值大小，同时要衡量收敛迭代值的相对 …

The following R codes illustrate how to fit the Accelerated Failure Time models. ## is -4.2e+02 (threshold: -1.0e-05). This might indicate that the optimization. ## did not converge to the maximum likelihood, so that the results are invalid. ## matrix. Let’s break down this code into smaller chunks to understand what is going on in each one…

Mastering Statistics with R. 19.6 Accelerated Failure Time (AFT) Model Accelerated Failure Time (AFT) Model

aftgee: Accelerated Failure Time Model with Generalized Estimating Equations. A collection of methods for both the rank-based estimates and least-square estimates to the Accelerated Failure Time (AFT) model.

2016年12月15日 · 本文介绍了R语言中的生存分析方法，包括Surv函数用于创建生存对象，survreg函数拟合参数生存回归模型，如Weibull分布，并讨论了不同类型的删失数据。 此外，还提到了survdiff函数用于比较生存曲线之间的差异，以及如何选择合适的检验方法。 通过示例代码，解释了如何设置计算误差和选择检验类型。 scale = 0) Value Std. Error z p. 画生存函数图. geom_line(colour="green")+ . ggtitle("s(t) \n 生存函数") 1. Surv. 创建一个生存对象，通常用作 …

We developed an R package ’afthd’ that works with an advanced AFT model for high-dimensional time-to-event data under the Bayesian paradigm and also provides different diagnostics plots for univariate and multivariable Bayesian analysis.

2020年2月29日 · R code for implementing the method in article “Pang M, Platt R, Schuster T, Abrahamowicz M. Flexible Modeling of Time-dependent and Non-linear Covariate Effects in Accelerated Failure Time Model. Under review at Statistical Methods in Medical Research 2020". A flexible extension of the accelerated failure time model that models:

To translate the coefficient in an AFT model \ ( \alpha_j \) to that of a PH model \ ( \beta_j \), \ ( \beta_j = -\alpha_j p \) where \ ( p \) is the shape parameter. For this example, the coefficient is multiplied by -1, then multiplied by the shape parameter (1/scale parameter = 1/1 for exponential model). exp (-0.516 * -1 * 1/1) = 1.68.

2020年6月8日 · We demonstrate with real and simulated experiments the effectiveness of AFT in XGBoost with respect to a number of baselines, in two respects: generalization performance and training speed. Furthermore, we take advantage of the support for NVIDIA GPUs in XGBoost to achieve substantial speedup over multi-core CPUs.

2024年10月29日 · aft: Parametric accelerated failure time model with smooth time... This implements the accelerated failure time models S_0 (t exp (beta x)) and S_0 (int_0^t exp (beta x (u)) du). The baseline function S_0 (t*) is modelled as exp (-exp (eta_0 (log (t*)))), where eta_0 (log (t*)) is a linear predictor using natural splines.

R: aftgee: Accelerated Failure Time with Generalized Estimating... A package that uses Generalized Estimating Equations (GEE) to estimate Multivariate Accelerated Failure Time Model (AFT). This package implements recently developed inference procedures for AFT models with both the rank-based approach and the least squares approach.

2024年8月13日 · To tackle those challenges and derive a reliable estimation with efficiently computational implementation, we develop the R package AFFECT, which is referred to Accelerated Functional Failure time model with Error-Contaminated survival Times.

2014年11月1日 · This paper describes an R package aft g gee that implements recently developed inference procedures for AFT models with both the rank-based approach and the least squares approach.

AFTs constitute and important class of models as they can handle censored, highly skewed data – exactly the type of data one would expect to collect when analyzing the failure times of a machine, or the survival times of a group of patients under study.

2022年9月11日 · AFT模型与Cox模型的区别在于，它为基准失效时间指定了概率分布形式，从而确定了基准风险函数的形式，因此它是一个参数模型（Cox模型为半参数模型）。 对失效时间进行建模，有. 其中，表示在基准生存函数下的失效时间。 两边取对数得. 是一个随机变量，服从一定的概率分布形式。 对进行标准化得. 代入得. 上式称为AFT模型的一般形式 [1]，称作尺度参数（scale parameter）。 AFT模型最初也被称作对数位置-尺度模型（Log-Location Scale Model） 因 …

R: Parametric accelerated failure time model with smooth time... This implements the accelerated failure time models S_0 (t exp (beta x)) and S_0 (int_0^t exp (beta x (u)) du). The baseline function S_0 (t*) is modelled as exp (-exp (eta_0 (log (t*)))), where eta_0 (log (t*)) is a linear predictor using natural splines.

Fits a semiparametric accelerated failure time (AFT) model with least-squares approach. Generalized estimating equation is generalized to multivariate AFT modeling to account for multivariate dependence through working correlation structures to improve efficiency. formula, data, subset, id = NULL, contrasts = NULL, weights = NULL, margin = NULL,