- 097 858 4477 - 094 558 4477
- duongxuanqua@gmail.com

Công ty TNHH MTV Công Nghệ Sau Thu Hoạch Dương Xuân Quả

Chuyên sản xuất, lắp đặt lò sấy từ 500kg/mẻ đến 150tấn/mẻ

Mã số thuế: **1602085926**

**TP.Long Xuyên, An Giang**

Ngày đăng : **14/06/2022**

The continuous predictor X is discretized into a categorical covariate X ? with low range (X < X_{1k}), median range (X_{1k} < X < X_{dosk}), and high range (X > X_{2k}) according to each pair of candidate cut-points.

Then the categorical covariate X ? (source top 's the median diversity) is equipped inside a good Cox model therefore the concomitant Akaike Advice Standards (AIC) worthy of is determined. The two from slash-issues that decrease AIC beliefs is understood to be max clipped-circumstances. More over, choosing slashed-factors by Bayesian pointers standards (BIC) gets the exact same efficiency due to the fact AIC (Additional file step one: Dining tables S1, S2 and S3).

The optimal equal-HR method was implemented in the language R (version 3.3.3). The freely available R package ‘survival' was used to fit Cox models with P-splines. The R package ‘pec' was employed for computing the Integrated Brier Score (IBS). The R package ‘maxstat' was used to implement the minimum p-value method with log-rank statistics. And an R package named ‘CutpointsOEHR' was developed for the optimal equal-HR method. This package could be installed in R by coding devtools::install_github(“yimi-chen/CutpointsOEHR”). All tests were two-sided and considered statistically significant at P < 0.05.

An effective Monte Carlo simulation analysis was used to evaluate the latest efficiency of your optimum equal-Hour method or any other discretization methods for instance the average split up (Median), the top of and lower quartiles beliefs (Q1Q3), as well as the lowest record-score take to p-value means (minP). To investigate the fresh overall performance of them tips, the fresh new predictive overall performance out-of Cox models suitable with assorted discretized details is analyzed.

U(0, 1), ? was the size factor out-of Weibull delivery, v is actually the shape parameter away from Weibull shipping, x was an ongoing covariate from a fundamental typical shipment, and you can s(x) are the brand new given function of interest. So you can replicate U-designed matchmaking ranging from x and you will record(?), the type of s(x) is set to become

where parameters k_{1}, k_{2} and a were used to control the symmetric and asymmetric U-shaped relationships. When -k_{1} was equal to k_{2}, the relationship was almost symmetric. For each subject, censoring time C was simulated by the uniform distribution with [0, r]. The final observed survival time was T = min(T_{0}, C), and d was a censoring indicator of whether the event happened or not in the observed time T (d = 1 if T_{0} ? C, else d = 0). The parameter r was used to control the censoring proportion P_{c}.

One hundred independent datasets were simulated with n = 500 subjects per dataset for various combinations of parameters k_{1}, k_{2}, a, v and P_{c}. Moreover, the simulation results of different sample sizes were shown in the supplementary file, Additional file 1: Figures S1 and S2. The values of (k_{1}, k_{2}, a) were set to be (? 2, 2, 0), (? 8/3, 8/5, ? 1/2), (? 8/5, 8/3, 1/2), (? 4, 4/3, ? 1), and (? 4/3, 4, 1), which were intuitively presented in Fig. 2. Large absolute values of a meant that the U-shaped relationship was more asymmetric than that with small absolute values of a. Peak asymmetry factor of the above (k_{1}, k_{2}, a) values were 1, 5/3, 3/5, 3, 1/3, respectively. The survival times were Weibull distributed with the decreasing (v = 1/2), constant (v = 1) and increasing (v = 5) hazard rates cheekylovers chat. The scale parameter of Weibull distribution was set to be 1. The censoring proportion P_{c} was set to be 0, 20 and 50%. For each scenario, the median method, the Q1Q3 method, the minP method and the optimal equal-HR method were performed to find the optimal cut-points.