2,639 research outputs found
A Mouse That Ate an Elephant; The Russo Finnish War in the Air
Among the strangest stories of WW II, is the defeat of the Russian Air Force by Finland. Hear the fascinating, true story from Ron Anderson, a member of the Finnish WW II Historical Group. Learn how 114 Finnish aircraft fought 3880 Russian planes and won. They did lose some land which caused a Russian General to comment “We won just enough territory to bury all the men we lost.
Reusable rocket engine intelligent control system framework design, phase 2
Elements of an advanced functional framework for reusable rocket engine propulsion system control are presented for the Space Shuttle Main Engine (SSME) demonstration case. Functional elements of the baseline functional framework are defined in detail. The SSME failure modes are evaluated and specific failure modes identified for inclusion in the advanced functional framework diagnostic system. Active control of the SSME start transient is investigated, leading to the identification of a promising approach to mitigating start transient excursions. Key elements of the functional framework are simulated and demonstration cases are provided. Finally, the advanced function framework for control of reusable rocket engines is presented
First passage time exponent for higher-order random walks:Using Levy flights
We present a heuristic derivation of the first passage time exponent for the
integral of a random walk [Y. G. Sinai, Theor. Math. Phys. {\bf 90}, 219
(1992)]. Building on this derivation, we construct an estimation scheme to
understand the first passage time exponent for the integral of the integral of
a random walk, which is numerically observed to be . We discuss
the implications of this estimation scheme for the integral of a
random walk. For completeness, we also address the case. Finally, we
explore an application of these processes to an extended, elastic object being
pulled through a random potential by a uniform applied force. In so doing, we
demonstrate a time reparameterization freedom in the Langevin equation that
maps nonlinear stochastic processes into linear ones.Comment: 4 figures, submitted to PR
Noxious weed survey of the U.S. Air Force Academy and Farish Outdoor Recreation Area
Prepared for: U.S. Air Force Academy, Dept. of Natural Resources.April 15, 2003.Includes bibliographical references
Relationship between cardiovascular risk and lipid testing in one health care system: a retrospective cohort study.
BackgroundThe US Preventive Services Taskforce (USPSTF) recommends routine lipid screening beginning age 35 for men [1]. For women age 20 and older, as well as men age 20-34, screening is recommended if cardiovascular risk factors are present. Prior research has focused on underutilization but not overuse of lipid testing. The objective is to document over- and under-use of lipid testing in an insured population of persons at low, moderate and high cardiovascular disease (CVD) risk for persons not already on statins.MethodsThe study is a retrospective cohort study that included all adults without prior CVD who were continuously enrolled in a large integrated healthcare system from 2005 to 2010. Measures included lipid test frequency extracted from administrative data and Framingham cardiovascular risk equations applied using electronic medical record data. Five year lipid testing patterns were examined by age, sex and CVD risk. Generalized linear models were used to estimate the relative risk for over testing associated with patient characteristics.ResultsAmong males and females for whom testing is not recommended, 35.8 % and 61.5 % received at least one lipid test in the prior 5 years and 8.4 % and 24.4 % had two or more. Over-testing was associated with age, race, comorbidity, primary care use and neighborhood income. Among individuals at moderate and high-risk (not already treated with statins) and for whom screening is recommended, between 21.4 % and 25.1 % of individuals received no screening in the prior 5 years.ConclusionsBased on USPSTF lipid screening recommendations, this study documents substantial over-testing among individuals with low CVD risk and under-testing among individuals with moderate to high-risk not already on statins. Opportunity exists to better focus lipid screening efforts appropriate to CVD risk
Redsharc: A Programming Model and On-Chip Network for Multi-Core Systems on a Programmable Chip
The reconfigurable data-stream hardware software architecture (Redsharc) is a programming model and
network-on-a-chip solution designed to scale to meet the performance needs of multi-core Systems on a programmable chip (MCSoPC). Redsharc uses an abstract API that allows programmers to develop systems of simultaneously executing kernels, in software and/or hardware, that communicate over a seamless interface. Redsharc incorporates two on-chip networks that directly implement the API to support high-performance systems with numerous hardware kernels. This paper documents the API, describes the common infrastructure, and quantifies the performance of a complete implementation. Furthermore, the overhead, in terms of resource utilization, is reported along with the ability to integrate hard and soft processor cores with purely hardware kernels being demonstrated
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