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On Amicable Sequences And Orthogonal Designs, S. Georgiou, C. Koukouvinos, Jennifer Seberry
On Amicable Sequences And Orthogonal Designs, S. Georgiou, C. Koukouvinos, Jennifer Seberry
Professor Jennifer Seberry
In this paper we give a general theorem which can be used to multiply the length of amicable sequences keeping the amicability property and the type of the sequences. As a consequence we have that if there exist two, four or eight amicable sequences of length m and type (al, a2), (al, a2, a3, a4) or (al, a2, ... , a8) then there exist amicable sequences of length ℓ ≡ 0 (mod m) and of the same type. We also present a theorem that produces a set of 2v amicable sequences from a set of v (not necessary amicable) sequences …
On Full Orthogonal Designs In Order 56, S. Georgiou, C. Koukouvinos, Jennifer Seberry
On Full Orthogonal Designs In Order 56, S. Georgiou, C. Koukouvinos, Jennifer Seberry
Professor Jennifer Seberry
We find new full orthogonal designs in order 56 and show that of 1285 possible OD(56; s1, s2, s3, 56—s1—s2-s3) 163 are known, of 261 possible OD(56; s1, s2, 56—s1—s2) 179 are known. All possible OD(56; s1, 56 — s1) are known.
New Weighing Matrices And Orthogonal Designs Constructed Using Two Sequences With Zero Autocorrelation Function - A Review, C. Koukouvinos, Jennifer Seberry
New Weighing Matrices And Orthogonal Designs Constructed Using Two Sequences With Zero Autocorrelation Function - A Review, C. Koukouvinos, Jennifer Seberry
Professor Jennifer Seberry
The book, Orthogonal Designs: Quadratic Forms and Hadamard Matrices, Marcel Dekker, New York-Basel, 1979, by A. V. Geramita and Jennifer Seberry, has now been out of print for almost two decades. Many of the results on weighing matrices presented therein have been greatly improved. Here we review the theory, restate some results which are no longer available and expand on the existence of many new weighing matrices and orthogonal designs of order 2n where n is odd. We give a number of new constructions for orthogonal designs. Then using number theory, linear algebra and computer searches we find new weighing …
Orthogonal Designs Of Kharaghani Type: I, C. Koukouvinos, Jennifer Seberry
Orthogonal Designs Of Kharaghani Type: I, C. Koukouvinos, Jennifer Seberry
Professor Jennifer Seberry
We use an array given in H. Kharaghani, Arrays for orthogonal designs, J. Combin. Designs, 8 (2000), 166-173, to obtain infinite families of 8-variable Kharaghani type orthogonal designs, OD(8t; hi, kl, kl, kl, k2, k2, k2, k2), where k1 and k2 must be the sum of two squares. In particular we obtain infinite families of 8-variable Kharaghani type orthogonal designs, OD(8t; k, k, k, k, k, k, k, k). For odd t orthogonal designs of order ≡ 8( mod 16) can have at most eight variables.
On Full Orthogonal Designs In Order 72, S. Georgiou, C. Koukouvinos, Jennifer Seberry
On Full Orthogonal Designs In Order 72, S. Georgiou, C. Koukouvinos, Jennifer Seberry
Professor Jennifer Seberry
We find new full orthogonal designs in order 72 and show that of 2700 possible OD(72; s1, s2, s3, 72—s1—s2—s3) 335 are known, of 432 possible OD(72; s1, s2, 72—si—s2) 308 are known. All possible OD(72; s1, 72 — s1) are known.