44 research outputs found

    Reparametrisation of interest in non-uniform factorial designs

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    AbstractA definition of factorial effects relying on the treatment structure defined by the hierarchies is proposed. It applies to a non-uniform situation, where the number of levels of a nested factor within the classes defined by each set of levels of its nesting factors may vary. A reparametrisation whose parameters belongs to these factorial effects is obtained. The development is based on the notion of reference treatment design, a conceptual design that can be used as a basis of comparison to assess the properties of any factorial design

    Construction d'Orthogonaux dans les Groupes abéliens finis eet confusions d'effets dans les plans factoriels

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    RésuméCet article est consacré aux plans factoriels obtenus par la méthode DSIGN de Patterson (1976). Comme Bailey (1977) l'a montré l'étude des confusions d'effets dans ces plans d'expériences peut être menée en recherchant les orthogonaux de sousgroupes du groupe abélien fini des traitements. Le même procédé permet également de construire des plans vérifiant des confusions d'effets données. Nous présentons ici un algorithme de construction de tels orthogonaux qui passe par la décomposition primaire du groupe des traitements puis par la construction d'orthogonaux dans des p-groupes.AbstractThis paper is devoted to factorial designs generated by Patterson's (1976) DSIGN method. As stated by Bailey (1977), the identification of confounded effects may be done here by constructing annihilators of given subgroups of the treatment group

    Automatic generation of generalised regular factorial designs

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    Open Access for this article was paid for by the French Research Agency (ANR), project Escapade (ANR-12-AGRO-0003).The R package planor enables the user to search for, and construct, factorial designs satisfying given conditions. The user specifies the factors and their numbers of levels, the factorial terms which are assumed to be non-zero, and the subset of those which are to be estimated. Both block and treatment factors can be allowed for, and they may have either fixed or random effects, as well as hierarchy relationships. The designs are generalised regular designs, which means that each one is constructed by using a design key and that the underlying theory is that of finite abelian groups. The main theoretical results and algorithms on which planor is based are developed and illustrated, with the emphasis on mathematical rather than programming details. Sections 3–5 are dedicated to the elementary case, when the numbers of levels of all factors are powers of the same prime. The ineligible factorial terms associated with users’ specifications are defined and it is shown how they can be used to search for a design key by a backtrack algorithm. Then the results are extended to the case when different primes are involved, by making use of the Sylow decomposition of finite abelian groups. The proposed approach provides a unified framework for a wide range of factorial designs.Publisher PDFPeer reviewe

    Baryonic Regge trajectories with analyticity constraints

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    A model for baryonic Regge trajectories compatible with the threshold behavior required by unitarity and asymptotic behavior in agreement with analyticity constraints is given in explicit form. Widths and masses of the baryonic resonances on the N and Δ\Delta trajectories are reproduced. The MacDowell symmetry is exploited and an application is given.Comment: 12 pages, 6 figure
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