3,602 research outputs found
NASA Marshall Space Flight Center Range Report - May 2015
The following is a summary of the major meteorological/atmospheric projects and research that have been or currently are being accomplished at Marshall Space Flight Center (MSFC). Listed below are highlights of work done during the past 6 months in the Engineering Directorate (ED) and in the Science and Mission Systems Office (ZP)
MEASUREMENT OF PRICE RISK IN REVENUE INSURANCE: IMPLICATIONS OF DISTRIBUTIONAL ASSUMPTIONS
A variety of crop revenue insurance programs have recently been introduced. A critical component of revenue insurance contracts is quantifying the risk associated with stochastic prices. Forward-looking, market-based measures of price risk which are often available in form of options premia are preferable. Because such measures are not available for every crop, some current revenue insurance programs alternatively utilize historical price data to construct measures of price risk. This study evaluates the distributional implications of alternative methods for estimating price risk and deriving insurance premium rates. A variety of specification tests are employed to evaluate distributional assumptions. Conditional heteroskedasticity models are used to determine the extent to which price distributions may be characterized by nonconstant variances. In addition, these models are used to identify variables which may be used for conditioning distributions for rating purposes. Discrete mixtures of normals provide flexible parametric specifications capable of recognizing the skewness and kurtosis present in commodity pricesRisk and Uncertainty,
Defining the Natural Atmospheric Environment Requirements for the NASA Constellation Program
The National Aeronautics and Space Administration began developing a new vehicle under the Constellation Program to replace the Space Shuttle. The Ares-1 launch vehicle and the Orion capsule will be used to ferry crew and some payloads to the International Space Station and will also be used for new missions to the moon, As development of this new vehicle begins, the Natural Environments Branch at Marshall Space Flight Center has been tasked with defining the natural environments the vehicle will encounter and working with the program to develop natural environmental requirements for the vehicles' elements. An overview of the structure of the program is given, along with a description of the Constellation Design Specification for Natural Environments and the Constellation Natural Environments Definition for Design documents and how they apply to the Ares-I and Orion vehicles
Upper Atmospheric Monitoring for Ares I-X Ascent Loads and Trajectory Evaluation on the Day-of-Launch
During the launch countdown of the Ares I-X test vehicle, engineers from Langley Research Center will use profiles of atmospheric density and winds in evaluating vehicle ascent loads and controllability. A schedule for the release of balloons to measure atmospheric density and winds has been developed by the Natural Environments Branch at Marshall Space Flight Center to help ensure timely evaluation of the vehicle ascent loads and controllability parameters and support a successful launch of the Ares I-X vehicle
MEASUREMENT OF PRICE RISK IN REVENUE INSURANCE: IMPLICATIONS OF DISTRIBUTIONAL ASSUMPTIONS
A variety of crop revenue insurance programs is now available. These programs require measurement of price risk. This article investigates the appropriateness of distributional assumptions underlying current and proposed alternative actuarial methods. Our results find that prices are best modeled using a flexible mixture of normals distribution.Demand and Price Analysis, Risk and Uncertainty,
Evolving the service model for child and adolescent mental health services
A new model for a community mental health service for children and young people aged 0-18 years is described. This has been formulated after multi-level consultation including extensive user/carer involvement. The proposed model is multidisciplinary and integrated with multiagency provision, with smooth access onto and through care pathways. This model brings voluntary and statutory agencies into an integrated collaboration. It reinforces that social and emotional development and psychological functioning is everybody’s business and creates conditions where a child’s needs can be addressed on a day-to-day basis rather than through a “clinic-based model”.</jats:p
Current Activities and Capabilities of the Terrestrial Environment Group at NASA's Marshall Space Flight Center
The National Aeronautics and Space Administration (NASA) designated Marshall Space Flight Center (MSFC) the center of excellence for space transportation. The Aerospace Environments and Effects (AEE) team of the Electromagnetics and Aerospace Environments Branch (EL23) in the Systems Analysis and Integration Laboratory at MSFC, supports the center of excellence designation by providing near-Earth space, deep space, planetary, and terrestrial environments expertise to projects as required. The Terrestrial Environment (TE) group within the AEE team maintains an extensive TE data base. Statistics and models derived from this data are applied to the design and development of new aerospace vehicles, as well as performance enhancement of operational vehicles such as the Space Shuttle. The TE is defined as the Earth's atmospheric environment extending from the surface to orbital insertion altitudes (approximately 90 km)
Reflection Mode Diffraction Tomography
In the field of ultrasound diffraction tomography, a cross section of a weakly scattering object is reconstructed from measurements of the sound scattered from the insonified object. This research studies tomographic imaging algorithms that deal only with the sound that is backscattered from the object. The use of the backscattered sound provides higher resolution reconstructions due to the higher spatial frequency information about the object that is obtained from the backscatter. Unfortunately the cost of the high frequency information contained in the backscatter is the loss of low frequency information. Different approaches to compensate for this loss are discussed. An additional benefit of reflection mode tomography is that it has the advantage of requiring only 180° access to the object whereas transmission mode requires 360°. The charter of this research is to explore the effectiveness of current reflection mode diffraction tomography algorithms and to theoretically develop, as well as experimentally verify, new algorithms. Different scanning geometries with different methods of insonification are explored. Many different approaches to the analysis of the problem are taken
Degradation of a quantum directional reference frame as a random walk
We investigate if the degradation of a quantum directional reference frame
through repeated use can be modeled as a classical direction undergoing a
random walk on a sphere. We demonstrate that the behaviour of the fidelity for
a degrading quantum directional reference frame, defined as the average
probability of correctly determining the orientation of a test system, can be
fit precisely using such a model. Physically, the mechanism for the random walk
is the uncontrollable back-action on the reference frame due to its use in a
measurement of the direction of another system. However, we find that the
magnitude of the step size of this random walk is not given by our classical
model and must be determined from the full quantum description.Comment: 5 pages, no figures. Comments are welcome. v2: several changes to
clarify the key results. v3: journal reference added, acknowledgements and
references update
- …