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A comparison of piecewise cubic Hermite interpolating polynomials,cubic splines and piecewise linear functions for the approximation of projectile aerodynamics

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defence Technology（防务技术） 2019年第5期15卷 741-757页

作者： C.A.Rabbath d.corriveau defence R&d Canada Valcartier Research Centre

Modelling and simulation of projectile flight is at the core of ballistic computer software and is essential to the study of performance of rifles and projectiles in various engagement *** effective and representative numerical model of projectile flight requires a relatively good approximation of the *** aerodynamic coefficients of the projectile model should be described as a series of piecewise polynomial functions of the Mach number that ideally meet the following conditions:they are continuous,differentiable at least once,and have a relatively low *** paper provides the steps needed to generate such piecewise polynomial functions using readily available tools,and then compares Piecewise Cubic Hermite Interpolating Polynomial(PCHIP),cubic splines,and piecewise linear functions,and their variant,as potential curve fitting methods to approximate the aerodynamics of a generic small arms projectile.A key contribution of the paper is the application of PCHIP to the approximation of projectile aerodynamics,and its evaluation against a set of ***,the paper provides a baseline assessment of the impact of the polynomial functions on flight trajectory predictions obtained with 6-degree-of-freedom simulations of a generic projectile.

关键词： Aerodynamic coefficients Piecewise polynomial functions Cubic splines Curve fitting Piecewise linear functions Piecewise cubic Hermite interpolating polynomial Projectile modelling and simulation Fire control inputs Precision Ballistic computer software

A statistical method for the evaluation of projectile dispersion

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defence Technology（防务技术） 2017年第3期13卷 164-176页

作者： C.A.Rabbath d.corriveau defence R&d Canada

As part of a research program, an extensive study on the dispersion characteristics of eight different7.62 ? 51 mm ammunition types was conducted. The paper presents the main steps in the experimental and analytical process carried out to evaluate, namely to measure and compare, the dispersion characteristics of the ammunitions; namely,(1) identify the number of rounds to fire in the trials,(2) establish a test plan and the setup for the precision trials,(3) fire the rounds, following an established protocol for the experiments,(4) collect the impact points, and measure the performance through statistical measures,(5) perform a statistical analysis of dispersion applied to the results obtained in the trials, and(6)conclude on the ammunition characteristics. In particular, the paper proposes a statistical method to evaluate the precision of ammunitions fired with precision(Mann) barrels. The practical method relies on comparison of confidence intervals and hypothesis testing on the standard deviation of samples,namely the impact points. An algorithm is proposed to compare the variances of two or more populations of ammunitions.

关键词：统计方法评估试验计划散布弹丸色散特性发射精度统计指标

Effect of the firing position on aiming error and probability of hit

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defence Technology（防务技术） 2019年第5期15卷 713-720页

作者： d.corriveau C.A.Rabbath A.Goudreau defence R&d Canada 2459 De La Bravoure Rd.QuebecQC G3J 1X5Canada Munitions Experimental Test Center 2459 De La Bravoure Rd.QuebecQC G3J 1X5Canada

Sources of dispersions that contribute to delivery error and reduce the soldier performance in terms of hit probability are *** order to improve the warfighter performance,the source of the errors contributing to the inaccuracy and dispersion of the weapon systems must be *** include ammunition dispersion error,gun dispersion,aerodynamic jump and the aiming *** aiming error or gun pointing error is defined as the angle between the gun muzzle at the instant the trigger is pulled and the line of fire that corresponds to the intendent aim *** is a round-to-round *** weapons systems that include the rifle,the ammunition,a sight and a gunner,the aiming error was shown to be the single most important source of dispersion for the regular *** other words,for the general purpose rifle weapon system,the weak link is often the *** order to verify and quantify this assertion,an experimental investigation was carried out to determine the aiming error associated with general purpose rifle fired by *** aiming error was evaluated for various firing positions and scenarios using infantryman for ranges varying between 100 m and 500 *** results show that the aiming error is the main contributor to dispersion for the general purpose rifle fired by a non-specialized *** aiming error induced dispersion for unstressed and rested gunners is shown to be at best equivalent to that of the weapon fired from a bench rest by a *** Copyright(?) 2019 Production and hosting by Elsevier *** behalf of China Ordnance Society.

关键词： Aiming error Rifle Position Range dispersion

Influence of chamber misalignment on cased telescoped(CT) ammunition accuracy

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defence Technology（防务技术） 2016年第2期12卷 117-123页

作者： d.corriveau C.FLORIN PETRE dejence R&d Canada 2459 De La Bravoure Rd. Quebec QC G3J 1X5 Canada

As part of a research program, it was desired to better understand the impact of the rotating chamber alignment with the barrel throat on the precision and accuracy of a novel cased telescoped(CT) ammunition firing rifle. In order to perform the study, a baseline CT ammunition chamber which was concentric with a Mann barrel bore was manufactured. Additionally, six chambers were manufactured with an offset relative to the barrel bore. These chambers were used to simulate a misaligned chamber relative to the bore axis. Precision and accuracy tests were then performed at 200 m in an indoor range under controlled conditions. For this project, 5.56 mm CT ammunition was used. As the chamber axis offset relative to the gun bore was increased, the mean point of impact was displaced away from the target center. The shift in the impact location is explained by the presence of in-bore yaw which results in lateral throw-off and aerodynamic jump components. The linear theory of ballistics is used to establish a relationship between the chamber misalignment and the resulting projectile mean point of impact for a rifle developed to fire CT ammunition. This relationship allows for the prediction of the mean point of impact given a chamber misalignment.

关键词：精度测试弹药箱 CT 失调控制条件空气动力线性理论孔轴线

Performance and calibration of quark/gluon-jet taggers using 140 fb^(-1) of pp collisions at √s=13 TeV with the ATLAS detector

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Chinese Physics C 2024年第2期48卷 1-25页

作者： G. Aad B. Abbott K. Abeling N.J. Abicht S.H. Abidi A. Aboulhorma H. Abramowicz H. Abreu Y. Abulaiti B.S. Acharya C. Adam Bourdarios L. Adamczyk S.V. Addepalli M.J. Addison J. Adelman A. Adiguzel T. Adye A.A. Affolder Y. Afik M.N. Agaras J. Agarwala A. Aggarwal C. Agheorghiesei A. Ahmad F. Ahmadov W.S. Ahmed S. Ahuja X. Ai G. Aielli A. Aikot M. Ait Tamlihat B. Aitbenchikh I. Aizenberg M. Akbiyik T.P.A. Åkesson A.V. Akimov d. Akiyama N.N. Akolkar K. Al Khoury G.L. Alberghi J. Albert P. Albicocco G.L. Albouy S. Alderweireldt M. Aleksa I.N. Aleksandrov C. Alexa T. Alexopoulos F. Alfonsi M. Algren M. Alhroob B. Ali H.M.J. Ali S. Ali S.W. Alibocus M. Aliev G. Alimonti W. Alkakhi C. Allaire B.M.M. Allbrooke J.F. Allen C.A. Allendes Flores P.P. Allport A. Aloisio F. Alonso C. Alpigiani M. Alvarez Estevez A. Alvarez Fernandez M. Alves Cardoso M.G. Alviggi M. Aly Y. Amaral Coutinho A. Ambler C. Amelung M. Amerl C.G. Ames d. Amidei S.P. Amor dos Santos K.R. Amos V. Ananiev C. Anastopoulos T. Andeen J.K. Anders S.Y. Andrean A. Andreazza S. Angelidakis A. Angerami A.V. Anisenkov A. Annovi C. Antel M.T. Anthony E. Antipov M. Antonelli F. Anulli M. Aoki T. Aoki J.A. Aparisi Pozo M.A. Aparo L. Aperio Bella C. Appelt A. Apyan N. Aranzabal S.J. Arbiol Val C. Arcangeletti A.T.H. Arce E. Arena J-F. Arguin S. Argyropoulos J.-H. Arling O. Arnaez H. Arnold G. Artoni H. Asada K. Asai S. Asai N.A. Asbah J. Assahsah K. Assamagan R. Astalos S. Atashi R.J. Atkin M. Atkinson H. Atmani P.A. Atmasiddha K. Augsten S. Auricchio A.d. Auriol V.A. Austrup G. Avolio K. Axiotis G. Azuelos d. Babal H. Bachacou K. Bachas A. Bachiu F. Backman A. Badea P. Bagnaia M. Bahmani A.J. Bailey V.R. Bailey J.T. Baines L. Baines O.K. Baker E. Bakos d. Bakshi Gupta V. Balakrishnan R. Balasubramanian E.M. Baldin P. Balek E. Ballabene F. Balli L.M. Baltes W.K. Balunas J. Balz E. Banas M. Bandieramonte A. Bandyopadhyay S. Bansal L. Barak M. Barakat E.L. Barberio d. Barberis M. Barbero M.Z. Barel K.N. Barends T. Barillari M-S. Barisits T. Barklow P. Baron d.A. Baron Mo The ATLAS Collaboration

The identification of jets originating from quarks and gluons,often referred to as quark/gluon tagging,plays an important role in various analyses performed at the Large Hadron Collider,as Standard Model measurements and searches for new particles decaying to quarks often rely on suppressing a large gluon-induced *** paper describes the measurement of the efficiencies of quark/gluon taggers developed within the ATLAS Collaboration,using √s=13 TeV proton–proton collision data with an integrated luminosity of 140 fb^(-1) collected by the ATLAS *** taggers with high performances in rejecting jets from gluon over jets from quarks are studied:one tagger is based on requirements on the number of inner-detector tracks associated with the jet,and the other combines several jet substructure observables using a boosted decision tree.A method is established to determine the quark/gluon fraction in data,by using quark/gluon-enriched subsamples defined by the jet *** in tagging efficiency between data and simulation are provided for jets with transverse momentum between 500 GeV and 2 TeV and for multiple tagger working points.

关键词： ATLAS JET QUARK GLUON TAGGING