9,542 research outputs found

    Measuring the Economic Effects of NAFTA on Mexico

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    Freihandelszone; Außenhandel; Wirtschaftspolitische Wirkungsanalyse; NAFTA-Staaten; Mexiko

    Collapse of large vapor bubbles

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    The refilling of propellant tanks while in a low-gravity environment requires that entrapped vapor bubbles be collapsed by increasing the system pressure. Tests were performed to verify the mechanism of collapse for these large vapor bubbles with the thermodynamic conditions, geometry, and boundary conditions being those applicable to propellant storage systems. For these conditions it was found that conduction heat transfer determined the collapse rate, with the specific bubble geometry having a significant influence

    Overview of the NASA/RECON educational, research, and development activities of the Computer Science Departments of the University of Southwestern Louisiana and Southern University

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    This document presents a brief overview of the scope of activities undertaken by the Computer Science Departments of the University of Southern Louisiana (USL) and Southern University (SU) pursuant to a contract with NASA. Presented are only basic identification data concerning the contract activities since subsequent entries within the Working Paper Series will be oriented specifically toward a detailed development and presentation of plans, methodologies, and results of each contract activity. Also included is a table of contents of the entire USL/DBMS NASA/RECON Working Paper Series

    Accounting quality under IFRS during stressed volatility: an examination of UK banks

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    This paper examines whether accounting quality is maintained for UK banks that report under the IFRS accounting standards during times of stressed market price volatility. We find that the UK banks’ accounting quality, measured from 1992 to 2008 using the relationship between total shareholders’ equity and market price, experienced a significant decrease during the high levels of market price volatility in 2008. This paper contributes to research that examines the IFRS accounting standards and to the examination of accounting quality in banks during periods of stressed volatility. Furthermore, this study concludes by calling for the examination of methods and processes to mitigate risks that impact on accounting quality

    NASA RECON: Course development, administration, and evaluation. A research and development proposal

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    This proposal addresses the development, administration, and evaluation of a set of transportable, college-level courses to educate science and engineering students in the effective use of automated scientific and technical information storage and retrieval systems, and, in particular, in the use of the NASA RECON system. Chapter 1 presents a brief introduction. Chapter 2 identifies general and specific objectives, i.e., needs analysis, course development, course administration, and course evaluation. Chapter 3 proposes the methodology to be used in successfully accomplishing these objectives. Chapter 4 highlights expected results and product deliverables, and Chapter 5 presents the project evaluation plan to be followed. Chapter 6 is a brief overview of the institutional resources available at the proposing institutions, i.e., at the University of Southwestern Louisiana and at Southern University to support the project. Chapter 7 proposes a budget, time schedule, and management plan. Chapter 8 is a summary of the foregoing

    An hierarchical approach to performance evaluation of expert systems

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    The number and size of expert systems is growing rapidly. Formal evaluation of these systems - which is not performed for many systems - increases the acceptability by the user community and hence their success. Hierarchical evaluation that had been conducted for computer systems is applied for expert system performance evaluation. Expert systems are also evaluated by treating them as software systems (or programs). This paper reports many of the basic concepts and ideas in the Performance Evaluation of Expert Systems Study being conducted at the University of Southwestern Louisiana

    Estimating short-period dynamics using an extended Kalman filter

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    An extended Kalman filter (EKF) is used to estimate the parameters of a low-order model from aircraft transient response data. The low-order model is a state space model derived from the short-period approximation of the longitudinal aircraft dynamics. The model corresponds to the pitch rate to stick force transfer function currently used in flying qualities analysis. Because of the model chosen, handling qualities information is also obtained. The parameters are estimated from flight data as well as from a six-degree-of-freedom, nonlinear simulation of the aircraft. These two estimates are then compared and the discrepancies noted. The low-order model is able to satisfactorily match both flight data and simulation data from a high-order computer simulation. The parameters obtained from the EKF analysis of flight data are compared to those obtained using frequency response analysis of the flight data. Time delays and damping ratios are compared and are in agreement. This technique demonstrates the potential to determine, in near real time, the extent of differences between computer models and the actual aircraft. Precise knowledge of these differences can help to determine the flying qualities of a test aircraft and lead to more efficient envelope expansion
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