2,025 research outputs found
A Sixth-Order Extension to the MATLAB Package bvp4c of J. Kierzenka and L. Shampine
A new two-point boundary value problem algorithm based upon the MATLAB bvp4c package of Kierzenka and Shampine is described. The algorithm, implemented in a new package bvp6c, uses the residual control framework of bvp4c (suitably modified for a more accurate finite difference approximation) to maintain a user specified accuracy. The new package is demonstrated to be as robust as the existing software, but more efficient for most problems, requiring fewer internal mesh points and evaluations to achieve the required accuracy
Virtual reality applications to automated rendezvous and capture
Virtual Reality (VR) is a rapidly developing Human/Computer Interface (HCI) technology. The evolution of high-speed graphics processors and development of specialized anthropomorphic user interface devices, that more fully involve the human senses, have enabled VR technology. Recently, the maturity of this technology has reached a level where it can be used as a tool in a variety of applications. This paper provides an overview of: VR technology, VR activities at Marshall Space Flight Center (MSFC), applications of VR to Automated Rendezvous and Capture (AR&C), and identifies areas of VR technology that requires further development
A Model for the Delivery of Evidence-Based PSHE (Personal Wellbeing) in Secondary Schools
Personal Social Health and Economic (PSHE) education is a non-statutory school subject designed to facilitate the delivery of a number of key competencies relevant to health, safety and wellbeing. As well as contributing to learning objectives in regards to these topics PSHE education has been ascribed with weighty expectations for outcomes well beyond the classroom relating to physical, mental, sexual and emotional health and safety. This paper reviews a programme of research aimed at providing guidance for the evidence-based provision of PSHE education, including a summary of the major impediments and facilitators of evidence-based programming, as well as a model curriculum for the delivery of evidence-based PSHE. An extensive literature review was conducted along with a series of interviews with programme developers, researchers, teachers and other school practitioners with the aim of developing a cohesive rationale for PSHE education and identifying evidence-based programmes which could be implemented to contribute to PSHE aims. The proposed model curriculum is comprised of evidence-based programmes which are PSHE-relevant and applicable or adaptable to the PSHE-education implementation context. While the provision of evidence-based PSHE presents a number of challenges and is limited by a lack of resources and evidence of effectiveness, with appropriate guidance PSHE education can be improved so that a comprehensive syllabus of evidence-based programmes is enacted in secondary schools. This will increase the likelihood that PSHE has the intended effect on adolescent mental and physical health and wellbeing.Health education, social-emotional learning, life-skills, prevention
Disconnect: An Animated Short Narrative Critiquing Our Society\u27s Digital Dependence
Disconnect is an animated short narrative critiquing our societyâs increasing focus on communication through digital devices at the expense of traditional human interaction
Haywood County\u27s Economic Dependence on Agriculture: An Input-Output Analysis
The purpose of this study was to measure the impact that agriculture and agriculturally related industries have on the economy of Haywood County. One motivation for this study was to gauge the validity of classifying Haywood County as not âfarm dependent,â which is the determination using the typology codes developed by the USDAâs Economic Research Service. The method used was to collect data on the expenditures of the agricultural industry in 2010 and incorporate those into the ready-made IMPLAN input-output model. The data were primarily collected from the Bureau of Economic Analysis and the Haywood County USDA Farm Service Agency. The revised model with the new data was then run to produce the multipliers used to show the total impacts of agriculture on the economy. Using those multipliers an impact on proprietor income was run to show the impacts of a change in that value. The results showed that despite the large differences in agriculture data there was not a substantial difference between the models in several respects. When compared with the rest of the industries in the county, the proportions of income and employment from agriculture were consistent with the ERS typology classification. However, including the agriculturally related industries would classify Haywood County as âfarm dependant.â Lastly, the results showed that agriculture had a higher impact on the rest of the economy per dollar of industry output than most other goods producing industries
The application of a two-dimensional sediment transport model in a Cumberland Plateau mountainous stream reach with complex morphology and coarse substrate
Among river engineers there is growing recognition that the success of a stream restoration project is dependent on the accurate prediction of sediment transport along a reach. To aid the design process, several numerical one- and multi-dimensional models have been developed to quantify in-stream sediment transport and hydraulic characteristics, and multiple sampling techniques have been proposed to establish the upstream sediment supply. However, the governing physical boundaries and variables (i.e., Manningâs ânâ variable, energy slope, and upstream sediment supply) required to initiate a sediment transport simulation are time consuming and difficult to measure in the field, and the estimation of these variables based on best professional judgment can lead to inaccurate predictions of sediment transport, resulting in the design of unstable projects. Thus, there exists a demand to understand the model sensitivity to key input parameters (i.e., Manningâs n value and sediment rating curves), and their effects on sediment transport simulations, especially when input parameters must be estimated and results can not be verified easily.
The goal of this study was to evaluate the performance of CCHE2D, a twodimensional sediment transport model, in a Cumberland Plateau mountainous stream reach with complex morphology and coarse substrate. The model was utilized to simulate sediment transport through a single hydrograph. Bed elevation change along a reach (100-m scale), was evaluated by comparing the deviation between simulated and measured elevations at multiple monitoring points before and after the simulated flood event. The study objective included testing the sensitivity of overall bed change at a reach, local, and point scales to two key model inputs parameters, the Manningâs n value and sediment supply.
Despite the relative stability observed along the site, simulated results show the model overestimated aggradation at a reach, local, and point scales. Statistical analysis of simulated results showed that bed elevation change was most sensitive to the bedload rating curve and Manningâs n value input parameters. Importantly, the site-specific bedload rating curve and measured roughness coefficient have the potential to reduce the error between simulated and measured results if accurate simulations of sediment transport can be achieved by a computational model
A Single Long-Term Acute Care Hospital Experience With a Pressure Ulcer Prevention Program
This study describes the experience of a single, long-term care acute hospital (LTAC) with the Medline Pressure Ulcer Prevention Program (mPUPP) The growing light being shed on pressure ulcer (PrU) costs for the people that get them and the health care systems that treat them, has challenged care facilities to look for programs to reduce nosocomial PrU Each PrU can cost between 135,000 in medical care related expenses and litigation Recent evidence suggests that successful PrU prevention programs have common characteristic
Hopf bifurcations in time-delay systems with band-limited feedback
We investigate the steady-state solution and its bifurcations in time-delay
systems with band-limited feedback. This is a first step in a rigorous study
concerning the effects of AC-coupled components in nonlinear devices with
time-delayed feedback. We show that the steady state is globally stable for
small feedback gain and that local stability is lost, generically, through a
Hopf bifurcation for larger feedback gain. We provide simple criteria that
determine whether the Hopf bifurcation is supercritical or subcritical based on
the knowledge of the first three terms in the Taylor-expansion of the
nonlinearity. Furthermore, the presence of double-Hopf bifurcations of the
steady state is shown, which indicates possible quasiperiodic and chaotic
dynamics in these systems. As a result of this investigation, we find that
AC-coupling introduces fundamental differences to systems of Ikeda-type [Ikeda
et al., Physica D 29 (1987) 223-235] already at the level of steady-state
bifurcations, e.g. bifurcations exist in which limit cycles are created with
periods other than the fundamental ``period-2'' mode found in Ikeda-type
systems.Comment: 32 pages, 5 figures, accepted for publication in Physica D: Nonlinear
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