Identifying optimal approaches to early termination in two-stage biomarker validation studies

2016 ◽  
Vol 66 (1) ◽  
pp. 187-199 ◽  
Author(s):  
Alexander M. Kaizer ◽  
Joseph S. Koopmeiners
Keyword(s):  
Validation Studies ◽  
Early Termination ◽  
Two Stage ◽  
Biomarker Validation

scholarly journals Statistical inference for net benefit measures in biomarker validation studies

Biometrics ◽  
2019 ◽  
Vol 76 (3) ◽  
pp. 843-852
Author(s):  
Tracey L. Marsh ◽  
Holly Janes ◽  
Margaret S. Pepe
Keyword(s):  
Statistical Inference ◽  
Validation Studies ◽  
Net Benefit ◽  
Biomarker Validation

scholarly journals Two-stage biomarker panel study and estimation allowing early termination for futility

Biostatistics ◽  
2015 ◽  
Vol 16 (4) ◽  
pp. 799-812 ◽  
Author(s):  
Shanshan Zhao ◽  
Yingye Zheng ◽  
Ross L. Prentice ◽  
Ziding Feng
Keyword(s):  
Panel Study ◽  
Early Termination ◽  
Two Stage ◽  
Biomarker Panel

scholarly journals Two-stage aerodynamic optimization method based on early termination of CFD convergence and variable-fidelity model

2021 ◽  
Vol 39 (1) ◽  
pp. 148-158
Author(s):  
Ji Miao ◽  
Chunlin Gong ◽  
Chunna Li
Keyword(s):  
Optimization Method ◽  
Aerodynamic Performance ◽  
Early Termination ◽  
Computational Time ◽  
High Fidelity ◽  
Aerodynamic Optimization ◽  
Two Stage ◽  
Optimization Stage ◽  
Variable Fidelity ◽  
Fidelity Model

Efficient aerodynamic design optimization method is of great value for improving the aerodynamic performance of little UAV's airfoil. Using engineering or semi-engineering estimation method to analyze aerodynamic forces in solving aerodynamic optimization problems costs little computational time, but the accuracy cannot be guaranteed. However, CFD method ensuring high accuracy needs much more computational cost, which is unfordable for optimization. Surrogate-based optimization can reduce the number of high-fidelity analyses to increase the optimization efficiency. However, the cost of CFD analyses is still huge for aerodynamic optimization due to multiple design variables, multi-optimal and strong nonlinearities. To solve this problem, a two-stage aerodynamic optimization method based on early termination of CFD convergence and variable-fidelity model is proposed. In the first optimization stage, the solutions by early termination CFD convergence and the convergenced CFD solutions are regarded as low-and high-fidelity data respectively for building variable-fidelity model. Then, the multi-island genetic algorithm is used in the global optimization based on the built variable-fidelity model. The modeling efficiency can be greatly improved due to many cheap low-fidelity data. In the second stage optimization, the global optimum from the first optimization stage is treated as the start of the Hooke-Jeeves algorithm to search locally based on convergenced CFD computations in order to acquire better-optimum. The proposed method is utilized in optimizing the aerodynamic performance of the airfoil of little UAV, and is compared with the EGO method based on single-fidelity Kriging surrogate model. The results show that the present two-level aerodynamic optimization method consumes less time.

scholarly journals Conditional estimation after a two-stage diagnostic biomarker study that allows early termination for futility

2012 ◽  
Vol 31 (5) ◽  
pp. 420-435 ◽  
Author(s):  
Joseph S. Koopmeiners ◽  
Ziding Feng ◽  
Margaret Sullivan Pepe
Keyword(s):  
Early Termination ◽  
Diagnostic Biomarker ◽  
Two Stage ◽  
Conditional Estimation

scholarly journals Early termination of a two-stage study to develop and validate a panel of biomarkers

2012 ◽  
Vol 32 (6) ◽  
pp. 1027-1037 ◽  
Author(s):  
Joseph S. Koopmeiners ◽  
Rachel Isaksson Vogel
Keyword(s):  
Early Termination ◽  
Two Stage

Two-stage self-seeding method for preparation of single crystals of poly(phenylene sulfide)

1989 ◽  
Vol 47 ◽  
pp. 368-369
Author(s):  
Sengshiu Chung ◽  
Peggy Cebe
Keyword(s):  
Single Crystals ◽  
High Performance ◽  
Dilute Solution ◽  
Two Stage ◽  
Annealing Behavior ◽  
High Performance Polymers ◽  
Seeding Method ◽  
Phenylene Sulfide

We are studying the crystallization and annealing behavior of high performance polymers, like poly(p-pheny1ene sulfide) PPS, and poly-(etheretherketone), PEEK. Our purpose is to determine whether PPS, which is similar in many ways to PEEK, undergoes reorganization during annealing. In an effort to address the issue of reorganization, we are studying solution grown single crystals of PPS as model materials.Observation of solution grown PPS crystals has been reported. Even from dilute solution, embrionic spherulites and aggregates were formed. We observe that these morphologies result when solutions containing uncrystallized polymer are cooled. To obtain samples of uniform single crystals, we have used two-stage self seeding and solution replacement techniques.

364: Two stage "Progressive Elongation of Spermatic Cord" Technique in Criptorchidism with very short Spermatic Vessels

2007 ◽  
Vol 177 (4S) ◽  
pp. 121-121
Author(s):  
Antonio Dessanti ◽  
Diego Falchetti ◽  
Marco Iannuccelli ◽  
Susanna Milianti ◽  
Gian P. Strusi ◽  
...  
Keyword(s):  
Spermatic Cord ◽  
Two Stage

360: A Contemporary Analysis of Two-Stage Hypospadias Repair

2007 ◽  
Vol 177 (4S) ◽  
pp. 120-120
Author(s):  
Pamela I. Ellsworth ◽  
Anthony Caldamone
Keyword(s):  
Hypospadias Repair ◽  
Two Stage

Two-Stage Gastric Surgery Urged for Superobese

2005 ◽  
Vol 38 (18) ◽  
pp. 68
Author(s):  
SHARON WORCESTER
Keyword(s):  
Gastric Surgery ◽  
Two Stage
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