A generic tool for cost estimating in aircraft design

A methodology to estimate the cost implications of design decisions by integrating cost as a design parameter at an early design stage is presented. The model is developed on a hierarchical basis, the manufacturing cost of aircraft fuselage panels being analysed in this paper. The manufacturing cost modelling is original and relies on a genetic-causal method where the drivers of each element of cost are identified relative to the process capability. The cost model is then extended to life cycle costing by computing the Direct Operating Cost as a function of acquisition cost and fuel burn, and coupled with a semi-empirical numerical analysis using Engineering Sciences Data Unit reference data to model the structural integrity of the fuselage shell with regard to material failure and various modes of buckling. The main finding of the paper is that the traditional minimum weight condition is a dated and sub-optimal approach to airframe structural design.

Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015: elaboration and explanation

Protocols of systematic reviews and meta-analyses allow for planning and documentation of review methods, act as a guard against arbitrary decision making during review conduct, enable readers to assess for the presence of selective reporting against completed reviews, and, when made publicly available, reduce duplication of efforts and potentially prompt collaboration. Evidence documenting the existence of selective reporting and excessive duplication of reviews on the same or similar topics is accumulating and many calls have been made in support of the documentation and public availability of review protocols. Several efforts have emerged in recent years to rectify these problems, including development of an international register for prospective reviews (PROSPERO) and launch of the first open access journal dedicated to the exclusive publication of systematic review products, including protocols (BioMed Central's Systematic Reviews). Furthering these efforts and building on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines, an international group of experts has created a guideline to improve the transparency, accuracy, completeness, and frequency of documented systematic review and meta-analysis protocols--PRISMA-P (for protocols) 2015. The PRISMA-P checklist contains 17 items considered to be essential and minimum components of a systematic review or meta-analysis protocol.This PRISMA-P 2015 Explanation and Elaboration paper provides readers with a full understanding of and evidence about the necessity of each item as well as a model example from an existing published protocol. This paper should be read together with the PRISMA-P 2015 statement. Systematic review authors and assessors are strongly encouraged to make use of PRISMA-P when drafting and appraising review protocols.

Outcome measurement and service evaluation - a note on research design.

The purpose of this research note is to demonstrate how an individualised quality of life instrument could be adapted to provide a more accurate estimate of the impact of a social service on a person’s quality of life. An increase in quality of life between the start and end of a service is often taken as an indication that the service impacted positively on quality of life. The modifications to the quality of life instrument suggested in this paper show that this assumption is not always accurate and should be questioned directly.

FACTORIAL EXPERIMENTAL-DESIGN FOR CONCRETE DURABILITY RESEARCH

It is widely accepted that concrete designed to perform satisfactorily in adverse environmental conditions must have a high cement content and a low water-cement ratio. In addition, in order to enhance its durability, many types of additive and admixture such as super-plasticizers, fly ash, silica fume, ggbfs, etc., have been used in the past. However, a close study of the published literature indicates that the effect of mix variables on the durability and the interaction between the various ingredients are not fully understood. Some of these apparent contradictions are due to the limitations in the design of the experimental programme. For instance, it is evident that relatively higher concentrations of aggregates increase the tortuosity of the flow path and hence reduce the permeability, which results in an improvement in the durability. Therefore, an increase in cement content without a proportional decrease in water-cement ratio may reduce the durability. In such cases, the interactive effects of factors can be established by resorting to a properly designed experimental programme, such as the factorial experimental design.

Defining a Research Agenda in Value Driven Design: Questions That Need to be Asked

Value driven design is an innovative design process that utilizes the optimization of a system level value function to determine the best possible design. This contrasts with more traditional systems engineering techniques, which rely on satisfying requirements to determine the design solution. While ‘design for value’ is intuitively acceptable, the transformation of value driven design concepts into practical tools and methods for its application is challenging. This, coupled with the growing popularity of value-centric design philosophies, has led to a proposed research agenda in value driven design. This research agenda asks fundamental questions about the design philosophy and attempts to identify areas of significant challenge. The research agenda is meant to stimulate discussion in the field, as well as prompt research that will lead to the development of tools and methodologies that will facilitate the application of value driven design and further the state of the art.

Design and Development of a Film-based Intervention about Teenage Men and Unintended Pregnancy: Applying the Medical Research Council Framework in Practice

Following the UK Medical Research Council’s (MRC) guidelines for the development and evaluation of complex interventions, this study aimed to design, develop and optimise an educational intervention about young men and unintended teenage pregnancy based around an interactive film. The process involved identification of the relevant evidence base, development of a theoretical understanding of the phenomenon of unintended teenage pregnancy in relation to young men, and exploratory mixed methods research. The result was an evidence-based, theory-informed, user-endorsed intervention designed to meet the much neglected pregnancy education needs of teenage men and intended to increase both boys’ and girls’ intentions to avoid an unplanned pregnancy during adolescence. In prioritising the development phase, this paper addresses a gap in the literature on the processes of research-informed intervention design. It illustrates the application of the MRC guidelines in practice while offering a critique and additional guidance to programme developers on the MRC prescribed processes of developing interventions. Key lessons learned were: 1) know and engage the target population and engage gatekeepers in addressing contextual complexities; 2) know the targeted behaviours and model a process of change; and 3) look beyond development to evaluation and implementation.

Research-informed design, management and maintenance of infrastructure slopes: development of a multi-scalar approach

The UK’s transport infrastructure is one of the most heavily used in the world. The performance of these networks is critically dependent on the performance of cutting and embankment slopes which make up £20B of the £60B asset value of major highway infrastructure alone. The rail network in particular is also one of the oldest in the world: many of these slopes are suffering high incidents of instability (increasing with time). This paper describes the development of a fundamental understanding of earthwork material and system behaviour, through the systematic integration of research across a range of spatial and temporal scales. Spatially these range from microscopic studies of soil fabric, through elemental materials behaviour to whole slope modelling and monitoring and scaling up to transport networks. Temporally, historical and current weather event sequences are being used to understand and model soil deterioration processes, and climate change scenarios to examine their potential effects on slope performance in futures up to and including the 2080s. The outputs of this research are being mapped onto the different spatial and temporal scales of infrastructure slope asset management to inform the design of new slopes through to changing the way in which investment is made into aging assets. The aim ultimately is to help create a more reliable, cost effective, safer and more resilient transport system.