A Method for the Reduction of Empirical Multi-Variable Functions

Allen, Cifford

doi:10.1093/comjnl/1.4.196

Cited by 4 publications

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“…This is reproduced below as a practical example of the application of the D function technique. Space does not permit an account of the actual curve fitting techniques employed, but basically the method of least^ squares was used to obtain a polynomial fit in a and /?, where a-sin 0 cos </> and /S = sin 8 sin <p. The method of Allen (1) is a possible alternative.…”

Section: Appendix a Typical Mathematical Modelmentioning

confidence: 99%

The Difference Function Approach to the Overall Aerodynamics of Guided Missiles

Forster¹,

Southgate²

1960

J. R. Aeronaut. Soc.

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Summary:With cruciform missiles it is usual to express overall aerodynamic forces and moments in terms of aileron, elevator and rudder angles. It is shown that an alternative formulation in terms of individual control angles is both more general and more revealing.The fundamental assumption is that the overall coefficients can be expressed sufficiently accurately as the sum of independent control effects and of the mutual interference between adjacent controls. This assumption has been found to be valid over quite wide regions of supersonic Mach number, body incidence and control deflection for some typical cruciform rear control missiles. In principle the method applies at all speeds and to all types of layout, but it seems likely to be less widely applicable at subsonic and transonic speeds and to moving wing and canard layouts. The region of applicability is ultimately a matter of experimental investigation for each missile.This new approach gives a clearer understanding of cross-coupling effects, simplifies and improves the accuracy of a mathematical model of the aerodynamic characteristics, and facilitates the interpolation of wind tunnel test measurements. These measurements are made on configurations with two adjacent controls deflected and the other two controls either always undeflected or always removed. The test programme can be matched more easily to the aerodynamic characteristics, and the testing time is much the same or significantly less than for a comparable programme involving combinations of aileron, elevator and rudder settings. Greater demands on experimental accuracy are imposed, however.There is considerable scope for research work in investigating the applicability of the new technique to various types of missile layouts and to assessing the relative merits of having the two dummy controls undeflected or removed.

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Section: Appendix a Typical Mathematical Modelmentioning

confidence: 99%

The Difference Function Approach to the Overall Aerodynamics of Guided Missiles

Forster¹,

Southgate²

1960

J. R. Aeronaut. Soc.

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Multivariable Problems

Hammersley¹,

Handscomb²

1964

Monte Carlo Methods

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Design of University Evaluation System based on Big Data

2020

J. Phys.: Conf. Ser.

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In the practice of early university evaluation, due to the backwardness of information technology and evaluation methods, the following problems were brought about: the social needs were neglected, the evaluation subject was single, the evaluation method was simple, and the evaluation data source was single. In the paper a big data model of university evaluation is presented, which studies the educational activities from 8 dimensions: core performance, innovation ability, teamwork, resources, audience willingness, parental evaluation, employer evaluation and social contribution. The model takes account of long-term, short-term factors, individual and overall factors, internal and external factors, educators and audience factors, etc., and carries out omnidirectional analysis. Every dimension is analyzed from 2 aspects: positive and negative. Then based on the model, an University Evaluation System based on Big Data (UESBD) was designed and implemented. Finally, the software was used to analyze the data of 20 colleges and universities from multiple dimensions to evaluate the educational activities of education.

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A Method for the Reduction of Empirical Multi-Variable Functions

Cited by 4 publications

References 0 publications

The Difference Function Approach to the Overall Aerodynamics of Guided Missiles

The Difference Function Approach to the Overall Aerodynamics of Guided Missiles

Multivariable Problems

Design of University Evaluation System based on Big Data

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