Forecasting Flying Hour Costs of the B-1, B-2, and B-52 Bomber Aircraft

This thesis both evaluates, and presents improvements to, the current method of forecasting flying costs of Air Force aircraft. It uses depot level repairable (DLR) and consumable (CONS) data for the Air Force\u27s bomber platforms: B-1B, B-2, and B-52H. The current forecasting method assumes a proportional relationship between costs and flying hours such that 1) when no hours are flown costs are zero, and 2) a 1% increase in flying hours will increase costs by 1%. The findings of this research indicate that applying log-linear ordinary least squares regression techniques may be an improved fit of flying cost data over the current proportional model; the actual data indicate a non-zero intercept and a less than proportional relationship between costs and flying hours. This research also found that models including factors other than flying hours as independent variables, such as sorties, lagged costs, and fiscal trends, may be more useful than models based solely on flying hours. Finally, this research found that estimating quarterly costs at the base-level may yield more accurate estimates than estimating at the monthly level, or mission design series level

Preprocessing Solar Images while Preserving their Latent Structure

Telescopes such as the Atmospheric Imaging Assembly aboard the Solar Dynamics Observatory, a NASA satellite, collect massive streams of high resolution images of the Sun through multiple wavelength filters. Reconstructing pixel-by-pixel thermal properties based on these images can be framed as an ill-posed inverse problem with Poisson noise, but this reconstruction is computationally expensive and there is disagreement among researchers about what regularization or prior assumptions are most appropriate. This article presents an image segmentation framework for preprocessing such images in order to reduce the data volume while preserving as much thermal information as possible for later downstream analyses. The resulting segmented images reflect thermal properties but do not depend on solving the ill-posed inverse problem. This allows users to avoid the Poisson inverse problem altogether or to tackle it on each of $\sim$10 segments rather than on each of $\sim$10$^7$ pixels, reducing computing time by a factor of $\sim$10$^6$. We employ a parametric class of dissimilarities that can be expressed as cosine dissimilarity functions or Hellinger distances between nonlinearly transformed vectors of multi-passband observations in each pixel. We develop a decision theoretic framework for choosing the dissimilarity that minimizes the expected loss that arises when estimating identifiable thermal properties based on segmented images rather than on a pixel-by-pixel basis. We also examine the efficacy of different dissimilarities for recovering clusters in the underlying thermal properties. The expected losses are computed under scientifically motivated prior distributions. Two simulation studies guide our choices of dissimilarity function. We illustrate our method by segmenting images of a coronal hole observed on 26 February 2015

Detecting Unspecified Structure in Low-Count Images

Unexpected structure in images of astronomical sources often presents itself upon visual inspection of the image, but such apparent structure may either correspond to true features in the source or be due to noise in the data. This paper presents a method for testing whether inferred structure in an image with Poisson noise represents a significant departure from a baseline (null) model of the image. To infer image structure, we conduct a Bayesian analysis of a full model that uses a multiscale component to allow flexible departures from the posited null model. As a test statistic, we use a tail probability of the posterior distribution under the full model. This choice of test statistic allows us to estimate a computationally efficient upper bound on a p-value that enables us to draw strong conclusions even when there are limited computational resources that can be devoted to simulations under the null model. We demonstrate the statistical performance of our method on simulated images. Applying our method to an X-ray image of the quasar 0730+257, we find significant evidence against the null model of a single point source and uniform background, lending support to the claim of an X-ray jet

Business models for sustained ehealth implementation: lessons from two continents

There is general consensus that Computers and Information Technology have the potential to enhance health systems applications, and many good examples of such applications exist all over the world. Unfortunately, with respect to eHealth and telemedicine, there is much disillusionment and scepticism. This paper describes two models that were developed separately, but had the same purpose, namely to facilitate a holistic approach to the development and implementation of eHealth solutions. The roadmap of the Centre for eHealth Research (CeHRes roadmap) was developed in the Netherlands, and the Telemedicine Maturity Model (TMMM) was developed in South Africa. The purpose of this paper is to analyse the commonalities and differences of these approaches, and to explore how they can be used to complement each other. The first part of this paper comprises of a comparison of these models in terms of origin, research domain and design principles. Case comparisons are then presented to illustrate how these models complement one another

LEARNING MANAGEMENT SYSTEMS: ENGINEERING THE EDUCATION INDUSTRY TO EDUCATE THE INDUSTRIAL ENGINEER

<P>ENGLISH ABSTRACT: A learning management system (LMS) is any infrastructure on which e-learning can be built and delivered. In this article two sides of the LMS coin are investigated: On the one side, it is argued that industrial and systems engineering skills are equally relevant for learning systems as for as for any other system. To support this argument, an analogy is drawn between the management of learning systems and the management of manufacturing systems. On the other side of the coin, the educational issues and concerns related to implementing an LMS at the University of Pretoria are investigated by means of a case study in the Industrial Engineering department. It is concluded that the industrial engineering educator is in the unique position of understanding and contributing towards the engineering of the education industry whilst educating the industrial engineer.</P><P>AFRIKAANSE OPSOMMING: ‘n Leerbestuurstelsel (LMS) is enige infrastruktuur waarop e-leer gebou en afgelewer kan word. In hierdie artikel word beide kante van die LMS muntstuk ondersoek: Aan die een kant word getoon dat bedryfsingenieursvaardighede en -beginsels ewe toepaslik is op leerstelsels as op vervaardigingstelsels. Om hierdie argument te steun word 'n analogie getrek tussen the bestuur van leerstelsels en die bestuur van vervaardigingstelsels. Aan die ander kant van die muntstuk word die opvoedkundige aspekte verbonde aan die implementering van ‘n leerbestuurstelsel (LMS) aan die Universiteit van Pretoria ondersoek aan die hand van ‘n gevallestudie in die Bedryfsingenieursdepartment. Die gevolgtrekking word gemaak dat die bedryfsingenieurs-opleier in 'n unieke posisie is om die opleidingsindustrie te begryp en by dra tot the ontwikkeling daarvan terwyl die bedryfsingenieur opgelei word.</P&gt

Psychological debriefing (PD) of trauma : a proposed model for Africa

CITATION: Van Dyk, E. L. & Van Dyk, G. A. J. 2010. Psychological debriefing (PD) of trauma : a proposed model for Africa. Journal for Transdisciplinary Research in Southern Africa, 6(2):a270, doi:10.4102/td.v6i2.270.The original publication is available at https://td-sa.netAfrica is a continent with severe trauma. Traumatic events include experiences of child soldiers, people living in war and conflict zones, and people struggling with the HIV/AIDS pandemic. These events cause high levels of trauma. The trauma causes psychological disorders like post traumatic stress disorder, acute stress disorder and combat stress reaction, specific in the military environment. This article focuses on a better understanding of the implications of trauma for military people and civilians. It discusses the different theories and models of psychological debriefing. Lastly the article discusses psychological debriefing models for military forces and the civil ian population to prevent severe psychopathology after traumatic incidents in Africa.https://td-sa.net/index.php/td/article/view/270Publisher's versio

Overcoming communication barriers in a multicultural radiography setting

Background: Effective communication between the patients and radiographers can be a daunting task in a multicultural, multilingual environment. With 11 official languages, South Africans experience language barriers amongst themselves, which pose unique communication challenges on a daily basis. It is thus important to explore how radiographers overcome such challenges to provide an effective service to their patients. Aim: The aim of this study was to explore and describe the experiences of radiographers in Gauteng province in communicating with patients in a multilingual, multicultural healthcare setting and make recommendations towards overcoming such barriers. Setting: The focus group discussions were conducted in English and at a private location that was convenient for the participants in Gauteng. Method: The study employed a qualitative phenomenological approach using focus group interviews (FGIs) to solicit the experiences of participants and gain an in-depth understanding of the phenomenon. Results: The findings showed that patient–radiographer cross-cultural communication is ineffective whilst language barriers are encountered daily. Participants subsequently offered a number of recommendations to enhance communication with patients from different cultural and linguistic backgrounds. These included workshops or short courses to improve language skills, posters to allow for non-verbal communication, the use of professional interpreters or mobile translation technology, employment of a diverse workforce and a focus on cultural sensitivity and learning an additional language at tertiary level. Conclusion: Although a variety of communication strategies are available, the most appropriate combination should be explored for individual radiology practices in order to serve their respective diverse patient base. Recommendations that emanated from this study can, therefore, be used as a guide to radiology practices to facilitate effective patient–radiographer communication

The reality of virtual reality at a South African university during the COVID-19 pandemic

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