Screening design with categorical factor: construction and evaluation

Screening designs are used widely by industrial experimentation. They are used to identify the most potential factors among a large number of factors. This thesis seeks to put into focus the construction of experimental designs and their analysis. In a recent paper, (Jones and Nachtsheim, 2011a) proposed a new class of designs called definitive screening designs DSDs. (Xiao et al., 2012) have used Conference matrices (C-matrix) to construct definitive screening designs DSDs with good properties. (Georgiou et al., 2013) introduced a method for constructing efficient three-level screening designs based on weighing matrices and their complete fold over. (Jones and Nachtsheim, 2013) have shown how a few categorical factors could be introduced in those designs. The study seeks to concentrate into Definitive Screening Designs DSDs and their generalizations: construction, properties and analysis. The consideration will be on the construction of new DSDs and study their properties and analysis. The various DSDs and their properties, including how they are constructed with respect to the situation under consideration, will be of interest in this study. In this research, we provide a new general method that can use weighing matrices to construct screening designs with some two level qualitative factors. The methodology is illustrated through a number of small examples in the thesis. The generated designs are compared to the designs in the literature and their advantages and disadvantages are discussed.Also, we provide a new analysis structure for designs (SDW1), (SDW2) and (SDW3). The construction of DSDs poses a great challenge in how to efficiently perform the experiment. Effective Design-Based Model Selection for Definitive Screening Designs is an approach that introduced by (Jones and Nachtsheim, 2017) for the analysis of DSDs that makes effective use of their special structure. The power of this approach is to detect the active main effects as well as the active second-order effects that far exceeds the capabilities of generic model selection tools, which do not take into account the structure of the data (see (Jones and Nachtsheim,2017)). In this thesis, we use the Effective Design-Based Model Selection procedure, that was introduced in (Jones and Nachtsheim, 2017) on Screening (SDWs) designs for s = (1, 2, 3) that constructed by (Alhelali et al., 2019). The method was applied to these designs for the first time and simulation studies with a number of different models has been applied. These models include main effects and second order terms and the procedure was evaluated by calculating the type I and type II error rates. A comparison between the performances of the screening designs (SDWs) for s = (1, 2, 3) is also provided with respect to the applied models and the resulted type I and type II error

Design of Experiments for Screening

The aim of this paper is to review methods of designing screening experiments, ranging from designs originally developed for physical experiments to those especially tailored to experiments on numerical models. The strengths and weaknesses of the various designs for screening variables in numerical models are discussed. First, classes of factorial designs for experiments to estimate main effects and interactions through a linear statistical model are described, specifically regular and nonregular fractional factorial designs, supersaturated designs and systematic fractional replicate designs. Generic issues of aliasing, bias and cancellation of factorial effects are discussed. Second, group screening experiments are considered including factorial group screening and sequential bifurcation. Third, random sampling plans are discussed including Latin hypercube sampling and sampling plans to estimate elementary effects. Fourth, a variety of modelling methods commonly employed with screening designs are briefly described. Finally, a novel study demonstrates six screening methods on two frequently-used exemplars, and their performances are compared

Preliminary design of graphite composite wing panels for commercial transport aircraft

Subjectively assessed practical and producible graphite/epoxy designs were subjected to a multilevel screening procedure which considered structural functions, efficiency, manufacturing and producibility, costs, maintainability, and inspectability. As each progressive screening level was reviewed, more definitive information on the structural efficiency (weight), manufacturing, and inspection procedures was established to support the design selection. The configuration features that enhance producibility of the final selected design can be used as a generic base for application to other wing panel designs. The selected panel design showed a weight saving of 25 percent over a conventional aluminum design meeting the same design requirements. The estimated cost reduction in manufacturing was 20 percent, based on 200 aircraft and projected 1985 automated composites manufacturing capability. The panel design background information developed will be used in the follow-on tasks to ensure that future panel development represents practical and producible design approaches to graphite/epoxy wing surface panels

Patient-centric trials for therapeutic development in precision oncology

An enhanced understanding of the molecular pathology of disease gained from genomic studies is facilitating the development of treatments that target discrete molecular subclasses of tumours. Considerable associated challenges include how to advance and implement targeted drug-development strategies. Precision medicine centres on delivering the most appropriate therapy to a patient on the basis of clinical and molecular features of their disease. The development of therapeutic agents that target molecular mechanisms is driving innovation in clinical-trial strategies. Although progress has been made, modifications to existing core paradigms in oncology drug development will be required to realize fully the promise of precision medicine

Workplace screening programs for chronic disease prevention: a rapid review

This review examined the effectiveness of workplace screening programs for chronic disease prevention based on evidence retrieved from the main databases of biomedical and health economic literature published to March 2012, supplemented with relevant reports. The review found: 1. Strong evidence of effectiveness of HRAs (when used in combination with other interventions) in relation to tobacco use, alcohol use, dietary fat intake, blood pressure and cholesterol 2. Sufficient evidence for effectiveness of worksite programs to control overweight and obesity 3. Sufficient evidence of effectiveness for workplace HRAs in combination with additional interventions to have favourable impact on the use of healthcare services (such as reductions in emergency department visits, outpatient visits, and inpatient hospital days over the longer term) 4. Sufficient evidence for effectiveness of benefits-linked financial incentives in increasing HRA and program participation 5. Sufficient evidence that for every dollar invested in these programs an annual gain of $3.20 (range$1.40 to $4.60) can be achieved 6. Promising evidence that even higher returns on investment can be achieved in programs incorporating newer technologies such as telephone coaching of high risk individuals and benefits-linked financial incentive

The Goldilocks Approach: A Review of Employing Design of Experiments in Prokaryotic Recombinant Protein Production

The production of high yields of soluble recombinant protein is one of the main objectives of protein biotechnology. Several factors, such as expression system, vector, host, media composition and induction conditions can influence recombinant protein yield. Identifying the most important factors for optimum protein expression may involve significant investment of time and considerable cost. To address this problem statistical models, such as Design of Experiments (DoE), have been used to optimise recombinant protein production. This review explores the application of DoE in the production of recombinant proteins, focusing on prokaryotic expression systems with a specific emphasis on media composition and culture conditions. The review examines the most commonly used DoE screening and optimisation methods, including factorial and screening designs. It provides examples of DoE informed media optimisation and culture condition optimisation. The review concludes with a consideration of the benefits of the application of DoE in recombinant protein production

A Comparison Study of Second-Order Screening Designs and Their Extension

Recent literature has proposed employing a single experimental design capable of preforming both factor screening and response surface estimation when conducting sequential experiments is unrealistic due to time, budget, or other constraints. Military systems, particularly aerodynamic systems, are complex. It is not unusual for these systems to exhibit nonlinear response behavior. Developmental testing may be tasked to characterize the nonlinear behavior of such systems while being restricted in how much testing can be accomplished. Second-order screening designs provide a means in a single design experiment to effectively focus test resources onto those factors driving system performance. Sponsored by the Office of the Secretary of Defense (ODS) in support of the Science of Test initiative, this research characterizes and adds to the area of second-order screening designs, particularly as applied to defense testing. Existing design methods are empirically tested and examined for robustness. The leading design method, a method that is very run efficient, is extended to overcome limitations when screening for non-linear effects. A case study and screening design guidance for defense testers is also provided

Schools Can't Wait: Accelerating the Redesign of University Principal Preparation Programs

Reviews recent efforts by 22 universities to provide higher quality training programs for school leaders. Includes examples of effective redesign practices and outlines an action plan for implementing successful educational leadership initiatives