“…The next three lemmas prove properties of P l,r . These results were shown as Theorem 1 in [2], but the proofs given here are significantly shorter and less complicated than the ones given there. These lemmas are used in Section 3 to prove the correctness of the construction given in this paper.…”
Section: Operations On Streamsmentioning
confidence: 71%
“…when s 0 = 0), then r has a run of l zeroes at index 0. Momentarily disregarding the fourth assumption that r has a run of l zeroes at index 0, we note that even if s 0 = 0, Lemma 2 shows that it is still possible to obtain a run of l zeroes in r. In [2], a special polynomial was constructed from r whose roots determine the exact conditions under which the run of l zeroes in r came from a run of l + 1 zeroes in s. This polynomial is:…”
Section: Operations On Streamsmentioning
confidence: 99%
“…Equivalently, γ is the number of β ∈ F q that are not roots of f . When f is primitive, γ = q and the resulting OOA(q t ; t, q + 1, t, q) is essentially the one produced in [2].…”
Section: Generalized Runs Constructionmentioning
confidence: 99%
“…By Theorem 9, this is an OOA (16; 4, 3, 4, 2) and is essentially the one that would be constructed by the RUNS construction of [2].…”
Section: Correctness Of the Constructionmentioning
confidence: 99%
“…
In [2], q t × (q + 1)t ordered orthogonal arrays (OOAs) of strength t over the alphabet F q were constructed using linear feedback shift register sequences (LFSRs) defined by primitive polynomials in F q [x]. In this paper we extend this result to all polynomials in F q [x] which satisfy some fairly simple restrictions, restrictions that are automatically satisfied by primitive polynomials.
In [2], q t × (q + 1)t ordered orthogonal arrays (OOAs) of strength t over the alphabet F q were constructed using linear feedback shift register sequences (LFSRs) defined by primitive polynomials in F q [x]. In this paper we extend this result to all polynomials in F q [x] which satisfy some fairly simple restrictions, restrictions that are automatically satisfied by primitive polynomials. While these restrictions sometimes reduce the number of columns produced from (q + 1)t to a smaller multiple of t, in many cases we still obtain the maximum number of columns in the constructed OOA when using non-primitive polynomials. For small values of q and t, we generate OOAs in this manner for all permissible polynomials of degree t in F q [x] and compare the results to the ones produced in [2], [16] and [17] showing how close the arrays are to being "full" orthogonal arrays. Unusually for finite fields, our arrays based on non-primitive irreducible and even reducible polynomials are closer to orthogonal arrays than those built from primitive polynomials.
“…The next three lemmas prove properties of P l,r . These results were shown as Theorem 1 in [2], but the proofs given here are significantly shorter and less complicated than the ones given there. These lemmas are used in Section 3 to prove the correctness of the construction given in this paper.…”
Section: Operations On Streamsmentioning
confidence: 71%
“…when s 0 = 0), then r has a run of l zeroes at index 0. Momentarily disregarding the fourth assumption that r has a run of l zeroes at index 0, we note that even if s 0 = 0, Lemma 2 shows that it is still possible to obtain a run of l zeroes in r. In [2], a special polynomial was constructed from r whose roots determine the exact conditions under which the run of l zeroes in r came from a run of l + 1 zeroes in s. This polynomial is:…”
Section: Operations On Streamsmentioning
confidence: 99%
“…Equivalently, γ is the number of β ∈ F q that are not roots of f . When f is primitive, γ = q and the resulting OOA(q t ; t, q + 1, t, q) is essentially the one produced in [2].…”
Section: Generalized Runs Constructionmentioning
confidence: 99%
“…By Theorem 9, this is an OOA (16; 4, 3, 4, 2) and is essentially the one that would be constructed by the RUNS construction of [2].…”
Section: Correctness Of the Constructionmentioning
confidence: 99%
“…
In [2], q t × (q + 1)t ordered orthogonal arrays (OOAs) of strength t over the alphabet F q were constructed using linear feedback shift register sequences (LFSRs) defined by primitive polynomials in F q [x]. In this paper we extend this result to all polynomials in F q [x] which satisfy some fairly simple restrictions, restrictions that are automatically satisfied by primitive polynomials.
In [2], q t × (q + 1)t ordered orthogonal arrays (OOAs) of strength t over the alphabet F q were constructed using linear feedback shift register sequences (LFSRs) defined by primitive polynomials in F q [x]. In this paper we extend this result to all polynomials in F q [x] which satisfy some fairly simple restrictions, restrictions that are automatically satisfied by primitive polynomials. While these restrictions sometimes reduce the number of columns produced from (q + 1)t to a smaller multiple of t, in many cases we still obtain the maximum number of columns in the constructed OOA when using non-primitive polynomials. For small values of q and t, we generate OOAs in this manner for all permissible polynomials of degree t in F q [x] and compare the results to the ones produced in [2], [16] and [17] showing how close the arrays are to being "full" orthogonal arrays. Unusually for finite fields, our arrays based on non-primitive irreducible and even reducible polynomials are closer to orthogonal arrays than those built from primitive polynomials.
This work shows several direct and recursive constructions of ordered covering arrays (OCAs) using projection, fusion, column augmentation, derivation, concatenation, and Cartesian product. Upper bounds on covering codes in Niederreiter-Rosenbloom-Tsfasman (shorten by NRT) spaces are also obtained by improving a general upper bound. We explore the connection between ordered covering arrays and covering codes in NRT spaces, which generalize similar results for the Hamming metric. Combining the new upper bounds for covering codes in NRT spaces and ordered covering arrays, we improve upper bounds on covering codes in NRT spaces for larger alphabets. We give tables comparing the new upper bounds for covering codes to existing ones.
We show that there exist ordered orthogonal arrays, whose sizes deviate from the Rao bound by a factor that is polynomial in the parameters of the ordered orthogonal array. The proof is nonconstructive and based on a probabilistic method due to Kuperberg, Lovett and Peled.
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