Experimental and analytical determination of characteristics affecting light aircraft landing-gear dynamics

An experimental and analytical investigation was conducted to determine which characteristics of a light aircraft landing gear influence gear dynamic behavior significantly. The investigation focused particularly on possible modification for load control. Pseudostatic tests were conducted to determine the gear fore-and-aft spring constant, axial friction as a function of drag load, brake pressure-torque characteristics, and tire force-deflection characteristics. To study dynamic tire response, vertical drops were conducted at impact velocities of 1.2, 1.5, and 1.8 m/s onto a level surface; to determine axial-friction effects, a second series of vertical drops were made at 1.5 m/s onto surfaces inclined 5 deg and 10 deg to the horizontal. An average dynamic axial-friction coefficient of 0.15 was obtained by comparing analytical data with inclined surface drop test data. Dynamic strut bending and associated axial friction were found to be severe for the drop tests on the 10 deg surface

Macroeconomic impacts of demographic change in Scotland : a computable general equilibrium analysis

This paper combines a multi-period economic Computable General Equilibrium (CGE) modelling framework with a demographic model to analyse the macroeconomic impact of the projected demographic trends in Scotland. Demographic trends are defined by the existing fertility-mortality rates and the level of annual net-migration. We employ a combination of a demographic and a CGE simulation to track the impact of changes in demographic structure upon macroeconomic variables under different scenarios for annual migration. We find that positive net migration can cancel the expected negative impact upon the labour market of other demographic changes. (Pressure on wages, falling employment). However, the required size of the annual net-migration is far higher than the current trends. The policy implication suggested by the results is that active policies are needed to attract migrants. We nevertheless report results when varying fertility and mortality assumptions. The impact of varying those assumptions is rather small

Revenue Generation In Hospital Foundations: Neural Network Versus Regression Model Recommendations

This paper looks at revenue amounts generated by non-profit hospital foundations throughout the US.  A number of inputs, including, among others, compensation, type of support given to the hospital, type of foundation expenditures, and hospital size, were used to develop models of foundation revenue.  Both neural network and regression models were developed and compared in order to see which one gave a better model and to see how they ranked the relative value of the input variables.  Though the generated value of revenue for both models correlates highly with actual revenue, the neural network shows smaller error.  The order of variable importance for the models is very different.  Each model would have different implications for foundations in planning their next round of revenue generating events

Robust Sampling for MITL Specifications

Real-time temporal logic reasoning about trajectories of physical systems necessitates models of time which are continuous. However, discrete time temporal logic reasoning is computationally more efficient than continuous time. Moreover, in a number of engineering applications only discrete time models are available for analysis. In this paper, we introduce a framework for testing MITL specifications on continuous time signals using only discrete time analysis. The motivating idea behind our approach is that if the dynamics of the signal fulfills certain conditions and the discrete time signal robustly satisfies the MITL specification, then the corresponding continuous time signal should also satisfy the same MITL specification

e-meducation.org: an open access medical education web portal

<p>Abstract</p> <p>Background</p> <p>Internet can serve in opening the door to a brand new world of high quality medical information. However, the chaotic size of data available in the WWW is often misleading. We sought to provide the world medical community with a web portal that may be used as a clearinghouse providing the outlet for dissemination of high quality WWW educational products.</p> <p>Methods</p> <p>Directories of the relevant WWW resources have been compiled and others are being currently under development to cover most medical fields. A custom-built medical search engine was created. Really Simple Syndication (RSS) feeds and video sharing services were reviewed for their quality and were presented along with case-based educational presentations through a user-friendly web portal interface. A directory of guidelines database is currently under development.</p> <p>Results</p> <p>The educational portal "e-meducation" available at <url>http://www.e-meducation.org/</url> has been launched in December 2006 and at the moment, provides links to more than 800 educational web-pages, more than 2100 clinical practice guidelines, 32 news feeds, and 14 educational videos. The web site also hosts 40 case-based presentations and a custom medical search engine.</p> <p>Conclusion</p> <p>Based on the incorporation of simple and tested educational strategies such as case based instruction and interactive learning, e-meducation.org aims to become a prototype platform that offers a more convenient interface to existing products, resources and medical contents.</p