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AbstractAbstract
[en] A method of evaluating experimental data yielding information on atomic masses is described. A prediction of values for atomic masses is given for which there is no direct information or for which the information is insufficient. The experimental data used are reaction energies and mass doublets
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15 Feb 1978; 91 p; 67 refs., 24 figs., 14 tables.; Proefschrift (Dr.).
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Miscellaneous
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Thesis/Dissertation
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Filges, D.
Kernforschungsanlage Juelich G.m.b.H. (Germany, F.R.). Inst. fuer Reaktorentwicklung; Technische Hochschule Aachen (Germany, F.R.)1977
Kernforschungsanlage Juelich G.m.b.H. (Germany, F.R.). Inst. fuer Reaktorentwicklung; Technische Hochschule Aachen (Germany, F.R.)1977
AbstractAbstract
[en] Different procedures for approximation and interpolation by using natural splines are studied and their applicability in analysis and curve fitting in experiments on reactor physics are shown. Using the definition of the natural spline function and its representation by B-splines in the first part of this seport solutions of data fitting by a Lagrange variational problem and by least square approximation are derived. The numerical problems arising from the solution of the linear systems of equations by fitting experimental data are well conditioned. In the second part the applications of fitting procedures are demonstrated. The analysis of dynamic transit reactivity measurements of simulated THTR pebbles in a critical facility are shown. The fissile content of the pebbles can be determined with minimum reproducibility. Calculations of photopeak parameters of Gamma-spectra and the evaluation of physical reactor parameters from noise measurements, e.g. of the prompt decay constant, give good results using the spline fitting methods. (orig.)
[de]
Verschiedene Approximations- bzw. Interpolationsverfahren mit der natuerlichen Spline-Funktion werden untersucht und ihre Anwendung zur Analyse und Interpretation von reaktorphysikalischen Experimenten dargestellt. Dabei wird im ersten Teil der Arbeit ausgehend von der Definition der natuerlichen Spline-Funktion im Zusammenhang mit der Darstellung durch B-Splines die Loesung von Minimal- bzw. Ausgleichsproblemen durch Splines herausgearbeitet, wobei Loesungen des Lagrange-Variationsproblems und die least squares Approximation abgeleitet werden. Gute Konditionierung der Verfahren zur Anwendung von Messdaten wird erreicht. Im zweiten Teil der Arbeit wird die Anwendung der Verfahren an Experimenten gezeigt. Hierbei wird die Auswertung der Messung dynamischer Probenbeeinflussfunktionen von simulierten THTR-Brennelementen zur Bestimmung des Spaltstoffgehaltes eines kugelfoermigen Brennelementes mit moeglichst kleinem Reproduzierbarkeitsfehler bei Nulleistung einer kritischen Anlage demonstriert. Untersuchungen ueber die Anwendung von Spline-Funktion zur Bestimmung von Photopeak-Parametern aus Gamma-Spektren und zur Auswertung von Korrelationsexperimenten schliessen sich an. (orig.)Original Title
Ein Beitrag zur Interpretation von reaktorphysikalischen Experimenten mit Hilfe von Spline-Funktionen
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Dec 1977; 113 p; 60 figs.; 33 tabs.; 46 refs.; Diss.
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Report
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Thesis/Dissertation
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AbstractAbstract
[en] A more careful count of the operations involved in solving the linear system associated with collocation of a two-point boundary value problem using a rough splines reverses results recently reported by others in this journal. In addition, it is observed that the use of the technique of ''condensation of parameters'' can decrease the computer storage required. Furthermore, the use of a particular highly localized basis can also reduce the setup time when the mesh is irregular. Finally, operation counts are roughly estimated for the solution of certain linear system associated with two competing collocation methods; namely, collocation with smooth splines and collocation of the equivalent first order system with continuous piecewise polynomials
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Journal Article
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Mathematics of Computation; v. 31(140); p. 916-921
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AbstractAbstract
No abstract available
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Journal Article
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J. Math. Phys. (N.Y.); v. 14(8); p. 1037-1048
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Kisel', I.V.; Konotopskaya, E.V.; Ososkov, G.A.; Chernov, N.I.
Joint Inst. for Nuclear Research, Dubna (USSR). Lab. of Computing Techniques and Automation1991
Joint Inst. for Nuclear Research, Dubna (USSR). Lab. of Computing Techniques and Automation1991
AbstractAbstract
[en] Applicability of the Crawford's method of circle fitting is investigated. Analytical expressions for the dependence of residuals and relative errors on radii fitted were evaluated in assumptions applicable to many physical facilities. The validity of these assumptions was examined by a numerical experiment carried out on the base of parameters of the ARES detector. 6 refs.; 4 figs
Original Title
Issledovanie granits primenimosti metoda Krauforda podgonki okruzhnosti
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1991; 12 p
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Report
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AbstractAbstract
[en] A new method for the automatic identification of peaks in a spectrum has been devised. A region centred on each channel i of the spectrum is fitted by a peak of given shape superimposed on a constant background. A maximum as a function of i in the height of the fitted peak is used to indicate the presence of a peak in the spectrum. Close-lying doublets and triplets that are resolved by other methods can be found using this method. The sensitivty of the method to small peaks and to fluctuations in the background has been investigated. Together with a least-squares peak fitting routine using the Marquardt algorithm, the peak search subroutine forms an automatic spectrum analysis program, which has been used extensively for the analysis of charged particle and γ-ray spectra. The peak shape used for these spectra consists of a Gaussian in the top, an exponential on the right-hand side and a double exponential on the left-hand side. Serveral examples of analysed spectra used for a test of the search and fitting methods are presented together with a discussion of the errors in the fitted parameters. (Auth.)
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Journal Article
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Nuclear Instruments and Methods; v. 128(3); p. 545-556
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AbstractAbstract
[en] The method of Becke and Sprung for generalizing the least squares fit to take into account the normalization errors is examined. It is found that their result for the error matrix of the fitting parameters is incorrect. The correct expression is given. (Auth.)
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Journal Article
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Nucl. Phys., A; ISSN 0029-5582; 
; v. 319(1-2); p. 175-181
; v. 319(1-2); p. 175-181
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AbstractAbstract
[en] The problem on application of the recurrence form for expanding the possibility for utilizing the least square method (LSM) is discussed. It is shown that the LSM recurrent form is applicable not only for the new data accountancy but for increase or decrease of the number of determinable parameters and for the change of acceptable model
Original Title
Rekurrentnaya forma metoda naimen'shikh kvadratov po opredelyaemym parametram
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Source
5 refs.
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Journal Article
Journal
Doklady Akademii Nauk - Rossijskaya Akademiya Nauk; ISSN 0869-5652; ; CODEN DAKNEQ; v. 349(5); p. 608-609
; CODEN DAKNEQ; v. 349(5); p. 608-609
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AbstractAbstract
[en] The formal basis for a data evaluation method is documented. This method was successfully applied to a variety of practical problems, and details important to these problems are included. The method can be crudely described as a means for using lognormal a priori information in the standard least-squares algorithm. Emphasis is on the proper use of uncertainties and correlations, both in the data to be evaluated and in the final evaluation itself. Finally, important details and pitfalls common to least-squares methods are included. 1 figure
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Journal Article
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Nuclear Science and Engineering; ISSN 0029-5639; ; v. 72(1); p. 19-34
; v. 72(1); p. 19-34
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AbstractAbstract
[en] Peelle's Pertinent Puzzle is introduced as an anomaly which appears in obtaining a least-squares average of two strongly correlated data. Reason of this anomaly is explained to be the inconsistency in transforming the data covariance and sensitivity matrices. Effects of data truncations give an explanation on another aspect of Peelle's Puzzle. (author)
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Nakajima, Yutaka (ed.) (Japanese Nuclear Data Committee, Tokai, Ibaraki (Japan)); Japan Atomic Energy Research Inst., Tokyo (Japan); 95 p; Mar 1994; p. 5-12; Specialists' meeting on covariance data; Tokai, Ibaraki (Japan); 15-16 Jul 1993
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