Development of Availability and Sustainability Spares Optimization Models for Aircraft Reparables

The Republic of Singapore Air Force (RSAF) conducts Logistics Support Analysis (LSA) studies in various engineering and logistics efforts on the myriad of weapon systems. In these studies, inventory spares provisioning, availability and sustainability analyses are key focus areas to ensure asset sustenance. In particular, OPUS10, a commercial-off-the-shelf software, is extensively used to conduct reparable spares optimization in acquisition programs. However, it is limited in its ability to conduct availability and sustainability analyses of time-varying operational demands, crucial in Operations & Support (O&S) and contingency planning. As the RSAF seeks force structure expansion to include more sophisticated weapon systems, the operating environment will become more complex. Agile and responsive logistics solutions are needed to ensure the RSAF engineering community consistently pushes for deepening competencies, particularly in LSA capabilities. This research is aimed at the development of a model solution that combines optimization and sustainability capabilities to meet the dynamic requirements in O&S and contingency planning. In particular, a unique dynamic operational profile conversion model was developed to realize these capabilities. It is envisaged that the research would afford the ease of use, versatility, speed and accuracy required in LSA studies, to provide the necessary edge in inventory reparable spares modeling

A User Manual for Benefit Cost Analysis Using Microsoft Excel

This manual has been prepared with support provided by the Economy and Environment Programme for South East Asia (EEPSEA) to enhance the capacity of researchers in carrying out practival applications of BCA using spreadsheet modeling and analysis. The framework and analyses presented are based on core concepts and theory of BCA, with applications that relate primarily to environmental and natural resource management. The manual demonstrates approaches and techniques using simple examples and case studies typical of those found in most countries in the South East Asia region. Preliminary versions of the manual have been used in training programs by EEPSEA.benefit cost analysis, excel

Theoretical Model Testing with Latent Variables

Topics include improving Average Variance Extracted (AVE), estimating a latent variable with only two indicators, and speeding up the weeding (itemizing) of a measure so it is consistent ( fits the data ), is valid and reliable, yet has more than 3 indicators

Study Guide Mathematical Modeling for Decision Making II DA 3410

The mission of the U.S. Army Special Operations Command is to organize, train, educate, man, equip, fund, administer, mobilize, deploy and sustain Army special operations forces to successfully conduct worldwide special operations, across the range of military operations, in support of regional combatant commanders, American ambassadors and other agencies as directed

From alpha to omega: a practical solution to the pervasive problem of internal consistency estimation

Coefficient alpha is the most popular measure of reliability (and certainly of internal consistency reliability) reported in psychological research. This is noteworthy given the numerous deficiencies of coefficient alpha documented in the psychometric literature. This mismatch between theory and practice appears to arise partly because users of psychological scales are unfamiliar with the psychometric literature on coefficient alpha and partly because alternatives to alpha are not widely known. We present a brief review of the psychometric literature on coefficient alpha, followed by a practical alternative in the form of coefficient omega. To facilitate the shift from alpha to omega we also present a brief guide to the calculation of point and interval estimates of omega using a free, open source software environment

Contributions towards understanding and building sustainable science

This dissertation focuses on either understanding and detecting threats to the epistemology of science (chapters 1-6) or making practical advances to remedy epistemological threats (chapters 7-9). Chapter 1 reviews the literature on responsible conduct of research, questionable research practices, and research misconduct. Chapter 2 reanalyzes Head et al (2015) their claims about widespread p-hacking for robustness. Chapter 3 examines 258,050 test results across 30,710 articles from eight high impact journals to investigate the existence of a peculiar prevalence of $p$-values just below .05 (i.e., a bump) in the psychological literature, and a potential increase thereof over time. Chapter 4 examines evidence for false negatives in nonsignificant results throughout psychology, gender effects, and the Reproducibility Project: Psychology. Chapter 5 describes a dataset that is the result of content mining 167,318 published articles for statistical test results reported according to the standards prescribed by the American Psychological Association (APA). In Chapter 6, I test the validity of statistical methods to detect fabricated data in two studies. Chapter 7 tackles the issue of data extraction from figures in scholarly publications. In Chapter 8 I argue that "after-the-fact" research papers do not help alleviate issues of access, selective publication, and reproducibility, but actually cause some of these threats because the chronology of the research cycle is lost in a research paper. I propose to give up the academic paper and propose a digitally native "as-you-go" alternative. In Chapter 9 I propose a technical design for this

A meta-review of transparency and reproducibility-related reporting practices in published meta-analyses on clinical psychological interventions (2000–2020)

Meta-analysis is a powerful and important tool to synthesize the literature about a research topic. Like other kinds of research, meta-analyses must be reproducible to be compliant with the principles of the scientific method. Furthermore, reproducible meta-analyses can be easily updated with new data and reanalysed applying new and more refined analysis techniques. We attempted to empirically assess the prevalence of transparency and reproducibility-related reporting practices in published meta-analyses from clinical psychology by examining a random sample of 100 meta-analyses. Our purpose was to identify the key points that could be improved, with the aim of providing some recommendations for carrying out reproducible meta-analyses. We conducted a meta-review of meta-analyses of psychological interventions published between 2000 and 2020. We searched PubMed, PsycInfo and Web of Science databases. A structured coding form to assess transparency indicators was created based on previous studies and existing meta-analysis guidelines. We found major issues concerning: completely reproducible search procedures report, specification of the exact method to compute effect sizes, choice of weighting factors and estimators, lack of availability of the raw statistics used to compute the effect size and of interoperability of available data, and practically total absence of analysis script code sharing. Based on our findings, we conclude with recommendations intended to improve the transparency, openness, and reproducibility-related reporting practices of meta-analyses in clinical psychology and related areas.This research has been funded with a grant from the Ministerio de Ciencia e Innovación and by FEDER funds (Project n° PID2019-104080GB-I00)