Order-of-addition experiments: A review and some new thoughts

Abstract

The study of order-of-addition (OofA) experiments is prevalent in many scientific and industrial areas. The statistical design of experiments (DOE) will considerably improve the efficiency of OofA experiments. Designing and modeling the OofA experiments have increasingly received a great deal of attention. In this article, we review the latest work on the design and model of OofA experiments, and introduce some new thoughts. We believe that this article will motivate fruitful applications in real OofA experiments as well as future developments in the methodology.     

Assessing robustness of factor ranking for supersaturated designs

Supersaturated designs can potentially be a beneficial tool for efficiently exploring a large number of factors with a moderately sized design. However, because more factors are being considered than there are runs, the stability of the identified factors depends heavily on effect sparsity and the lack of highly influential observations. A helpful tool for the analysis of supersaturated designs is least absolute shrinkage and selection operation (LASSO), which is useful when the effects of many explanatory variables are sparse in a high‐dimensional dataset. To understand the impact of individual observations on the selected factors, the LASSO influence plot was created. This paper describes an application of this plot and its variants that can be used to identify influential points, increase understanding of the impact of individual observations on model parameters, and the robustness of results in analyses with supersaturated designs. These graphical methods can serve as a complement to other regression diagnostics techniques in the LASSO regression setting.     

Three-level designs: Evaluation and comparison for screening purposes

Since their introduction by Box and Hunter, resolution criteria have been widely used when comparing regular fractional factorials designs. In this article, we investigate how a generalized resolution criterion can be used to assess some recently developed three-level screening designs, such as definitive screening designs (DSDs) and screening designs from weighing matrices. The aim of this paper is to capture the projection properties of those three-level screening designs, complementing the work of Deng and Tang, who used generalized resolution and minimum aberration criteria for ranking different two-level designs, particularly Plackett-Burman and other nonregular factorial designs. An advantage of generalized resolution, extended here to work on three-level designs, is that it offers a useful criterion for ranking three-level screening designs, whereas the Deng and Tang resolution is used mainly for the assessment of two-level designs. In addition, we applied a projection estimation capacity (PEC) criterion to select three-level screening designs with desirable properties. Practical examples and the best projections of the designs are presented in tables.     

均匀设计在岩土工程中的应用

介绍了均匀设计特点以及使用均匀设计表应注意的事项。均匀设计考虑试验点在试验范围内的均匀分布，利用均匀设计可以选到偏差更小的点，大大减少试验次数而获得较好的试验效果，因而适合于多因素多水平试验，并对非线性模型有较好的估计，这些特点使它适合于岩土工程领域。通过一个工程实例说明均匀设计在岩土工程领域的应用。最后，指出均匀设计应注意的问题，不能片面追求过少的试验次数，要注意关键因素的选择和试验范围的确定。     

Optimum design of laminated composite plates to maximize buckling load using MFD method

This paper presents optimal design of simply supported laminated composite plates subject to given in-plane static loads for which the critical failure mode is buckling. The objective function is to maximize the buckling load capacity of laminated plates and the fiber orientation is considered as design variable. The first-order shear deformation theory is used for the finite element analysis. In this paper, the effects of bending–twisting coupling are also included for the buckling optimization. The modified feasible direction method is used as an optimization method. Also, computer programs are coded in MATLAB and Golden Section method is adapted in this program for the optimal design of laminated plates for maximum buckling load. The effect of width-to-thickness ratio, aspect ratio, number of layers, material anisotropy, load ratios (N_y/N_x), uncertainties in material properties and functionally graded materials on the results is investigated and compared.     

江西九江-瑞昌房屋震害分析

对震区砖混房屋的震害及其造成的破坏因素进行了分析,并提出结构抗震改进措施,加强认识建筑抗震设计的基本准则：“小震不坏,中震可修,大震不倒”,最大限度地限制和减轻建筑物的地震破坏,避免人员伤亡,减少经济损失。     

从城市公共设施的现状谈设计计划

城市公共设施在国外也称之为城市家具,是展现城市风格和形象的重要窗口。存在于城市的公共空间,为市民、游客提供休憩、遮阳避雨、在城市结构中指明方向、规范引导人们的行为等功能,从而提高城市效率、美化城市环境景观,培养人的审美意识、营造一个亲和、有序和谐的氛围。目前,国内许多城市公共设施的现状在使用效率、合理性、统一性以及和环境的协调性等方面都不尽如人意,设施欠缺人性化的问题尤为突出的,究其原因,没有制定详尽的"设计计划"作为设计的依据和基础是问题存在的根本。     

Thermal behavior of gradient charring materials with improved iterative method

The lightweight material of the thermal protection system for a reentry vehicle has become a trend in order to maximize the payload. To explore the effect of gradient density on the thermal behavior of charring materials, a pyrolysis layer model considering of variable density is developed and discretized with the central difference method. An iterative method is improved to look for the locations of the moving interfaces and boundary in each time step. Taken different gradient phenolic impregnated carbon ablator under a return trajectory heat flux for the Orion vehicle as example, their thermal behavior and effective heat capacities are simulated using the code written. Numerical results indicate that the gradient designs can improve the thermal protection performance of charring materials effectively. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47076.     

The Modified Gauss-Newton Method for the Fitting of Non-Linear Regression Functions by Least Squares

Resolution III designs for 4³·2 ^m experiments are constructed. These plans are available in 4 ⁿ runs, where n is a multiple of four, and permit estimation of all main-effects orthogonally. Once the plans for 4³·2 ^m experiments are obtained, one can get orthogonal main-effect plans for experiments of the type 4 ^r 3 ^s 2 ^m by collapsing the levels of one or more four-level factors.