45,980 research outputs found
Generalized resolution for orthogonal arrays
The generalized word length pattern of an orthogonal array allows a ranking
of orthogonal arrays in terms of the generalized minimum aberration criterion
(Xu and Wu [Ann. Statist. 29 (2001) 1066-1077]). We provide a statistical
interpretation for the number of shortest words of an orthogonal array in terms
of sums of values (based on orthogonal coding) or sums of squared
canonical correlations (based on arbitrary coding). Directly related to these
results, we derive two versions of generalized resolution for qualitative
factors, both of which are generalizations of the generalized resolution by
Deng and Tang [Statist. Sinica 9 (1999) 1071-1082] and Tang and Deng [Ann.
Statist. 27 (1999) 1914-1926]. We provide a sufficient condition for one of
these to attain its upper bound, and we provide explicit upper bounds for two
classes of symmetric designs. Factor-wise generalized resolution values provide
useful additional detail.Comment: Published in at http://dx.doi.org/10.1214/14-AOS1205 the Annals of
Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical
Statistics (http://www.imstat.org
Fading-Resilient Super-Orthogonal Space-Time Signal Sets: Can Good Constellations Survive in Fading?
In this correspondence, first-tier indirect (direct) discernible
constellation expansions are defined for generalized orthogonal designs. The
expanded signal constellation, leading to so-called super-orthogonal codes,
allows the achievement of coding gains in addition to diversity gains enabled
by orthogonal designs. Conditions that allow the shape of an expanded
multidimensional constellation to be preserved at the channel output, on an
instantaneous basis, are derived. It is further shown that, for such
constellations, the channel alters neither the relative distances nor the
angles between signal points in the expanded signal constellation.Comment: 10 pages, 0 figures, 2 tables, uses IEEEtran.cls, submitted to IEEE
Transactions on Information Theor
Generalized packing designs
Generalized -designs, which form a common generalization of objects such
as -designs, resolvable designs and orthogonal arrays, were defined by
Cameron [P.J. Cameron, A generalisation of -designs, \emph{Discrete Math.}\
{\bf 309} (2009), 4835--4842]. In this paper, we define a related class of
combinatorial designs which simultaneously generalize packing designs and
packing arrays. We describe the sometimes surprising connections which these
generalized designs have with various known classes of combinatorial designs,
including Howell designs, partial Latin squares and several classes of triple
systems, and also concepts such as resolvability and block colouring of
ordinary designs and packings, and orthogonal resolutions and colourings.
Moreover, we derive bounds on the size of a generalized packing design and
construct optimal generalized packings in certain cases. In particular, we
provide methods for constructing maximum generalized packings with and
block size or 4.Comment: 38 pages, 2 figures, 5 tables, 2 appendices. Presented at 23rd
British Combinatorial Conference, July 201
J2 optimality and Multi-level Minimum Aberration Criteria in fractional factorial design
The desirable properties of fractional factorial design: Balance and orthogonal; was examined for near balance and near orthogonal using the balance coefficient and J2 optimality criteria respectively. Efficient orthogonal arrays with three factors having two, three and four levels were constructed with balance and orthogonal property for lowest common multiples of runs. The two forms of balance coefficient were used for classifying the designs into two and multi level minimum aberration criteria were used to determine designs with lesser aberration. It was observed that designs constructed using the maximum form of balance coefficient has the lesser aberration in both the generalized minimum aberration and minimum moment aberration criteria. The J2 – optimality criterion reveals that the higher the run of a design, the lesser it’s optimality value. Keywords: Balance Coefficient, fractional factorial, Generalized Minimum Aberration (GMA), J2 optimality and Minimum Moment Aberration (MMA).
A generalization of sum composition: Self orthogonal Latin square design with sub self orthogonal Latin square designs
AbstractA generalization of the theory of sum composition of Latin square designs is given. Via this generalized theory it is shown that a self orthogonal Latin square design of order (3pα − 1)2 with a subself orthogonal Latin square design of order (pα − 1)2 can be constructed for any prime p > 2 and any positive integer α as long as p ≠3, 5, 7 and 13 if α = 1. Additional results concerning sets of orthogonal Latin square designs are also provided
ANOTHER LOOK AT NEW GMA ORTHOGONAL ARRAYS
Non-regular factorial designs have not been advocated until last decade clue to their complex aliasing structure. However, some researchers recently found that the complex aliasing structure of non-regular factorial designs is a challenge as well as an opportunity. Li, Deng, and Tang (2000) studied nonl-regular designs and generated a collection of non-equivalent orthogonal arrays using a generalized miniumm aberration criterion, proposed by Deng and Tang (1999). Some new orthogonal arrays they found cannot be embedded into Hadamard matrices. In this paper, we study these orthogonal arrays from the angle of projection. We show that these new GMA orthogonal arrays are also superior to the top designs obtained from Hadamard matrices when evaluated hy the criteria of model estimability and design efficiency
Construction of optimal multi-level supersaturated designs
A supersaturated design is a design whose run size is not large enough for
estimating all the main effects. The goodness of multi-level supersaturated
designs can be judged by the generalized minimum aberration criterion proposed
by Xu and Wu [Ann. Statist. 29 (2001) 1066--1077]. A new lower bound is derived
and general construction methods are proposed for multi-level supersaturated
designs. Inspired by the Addelman--Kempthorne construction of orthogonal
arrays, several classes of optimal multi-level supersaturated designs are given
in explicit form: Columns are labeled with linear or quadratic polynomials and
rows are points over a finite field. Additive characters are used to study the
properties of resulting designs. Some small optimal supersaturated designs of
3, 4 and 5 levels are listed with their properties.Comment: Published at http://dx.doi.org/10.1214/009053605000000688 in the
Annals of Statistics (http://www.imstat.org/aos/) by the Institute of
Mathematical Statistics (http://www.imstat.org
- …