Journal of Combinatorial Designs (J Combin Des )

Publisher: Wiley InterScience (Online service), John Wiley & Sons

Description

The Journal of Combinatorial Designs is an international journal devoted to the timely publication of the most influential papers in the area of combinatorial design theory. All topics in design theory and in which design theory has important applications are covered including: block designs t-designs pairwise balanced designs and group divisible designs Latin squares quasigroups and related algebras computational methods in design theory construction methods applications in computer science experimental design theory and coding theory graph decompositions factorizations and design-theoretic techniques in graph theory and extremal combinatorics finite geometry and its relation with design theory. algebraic aspects of design theory. Researchers and scientists can depend on the Journal of Combinatorial Designs for the most recent developments in this rapidly growing field and to provide a forum for both theoretical research and applications.

  • Impact factor
    0.69
  • 5-year impact
    0.63
  • Cited half-life
    8.20
  • Immediacy index
    0.12
  • Eigenfactor
    0.00
  • Article influence
    0.65
  • Website
    Journal of Combinatorial Designs website
  • Other titles
    Journal of combinatorial designs (Online), Journal of combinatorial designs
  • ISSN
    1520-6610
  • OCLC
    41616630
  • Material type
    Document, Periodical, Internet resource
  • Document type
    Internet Resource, Computer File, Journal / Magazine / Newspaper

Publisher details

John Wiley & Sons

  • Pre-print
    • Author can archive a pre-print version
  • Post-print
    • Author can archive a post-print version
  • Conditions
    • See Wiley-Blackwell entry for articles after February 2007
    • On personal web site or secure external website at authors institution
    • Not allowed on institutional repository
    • JASIST authors may deposit in an institutional repository
    • Non-commercial
    • Pre-print must be accompanied with set phrase (see individual journal copyright transfer agreements)
    • Published source must be acknowledged with set phrase (see individual journal copyright transfer agreements)
    • Publisher's version/PDF cannot be used
    • Articles in some journals can be made Open Access on payment of additional charge
    • 'John Wiley and Sons' is an imprint of 'Wiley-Blackwell'
  • Classification
    ​ green

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: Candelabra quadruple systems (CQS) were first introduced by Hanani who used them to determine the existence of Steiner quadruple systems. In this paper, a new method has been developed by constructing partial candelabra quadruple systems with odd group size, which is a generalization of the even cases, to complete a design. New results of candelabra quadruple systems have been obtained, i.e. we show that for any , there exists a CQS for all , and .
    Journal of Combinatorial Designs 09/2014;
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    ABSTRACT: Given five positive integers and t where and a t-general covering design is a pair where X is a set of n elements (called points) and a multiset of k-subsets of X (called blocks) such that every p-subset of X intersects at least λ blocks of in at least t points. In this article we continue the work carried out by Etzion, Wei, and Zhang [Des. Codes Cryptogr. 5 (1995), 217–239] on the asymptotic covering density of general covering designs. We will present combinatorial constructions leading to new upper bounds on the asymptotic covering density of 4-(n, 4, 6, 1) general covering designs and 4- general covering designs with . The new bound on the asymptotic covering density of 4-(n, 4, 6, 1) general covering designs is equivalent to a new lower bound for the Turán density .
    Journal of Combinatorial Designs 09/2014;
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    ABSTRACT: The notion of a symmetric Hamiltonian cycle system (HCS) of a graph Γ has been introduced and studied by J. Akiyama, M. Kobayashi, and G. Nakamura [J Combin Des 12 (2004), 39–45] for , by R. A. Brualdi and M. W. Schroeder [J Combin Des 19 (2011), 1–15] for , and then naturally extended by V. Chitra and A. Muthusamy [Discussiones Mathematicae Graph Theory, to appear] to the multigraphs and . In each case, there must be an involutory permutation ψ of the vertices fixing all the cycles of the HCS and at most one vertex. Furthermore, for , this ψ should be precisely the permutation switching all pairs of endpoints of the edges of I.An HCS is cyclic if it is invariant under some cyclic permutation of all the vertices. The existence question for a cyclic HCS of has been completely solved by Jordon and Morris [Discrete Math (2008), 2440–2449]—and we note that their cyclic construction is also symmetric for (mod 8). It is then natural to study the existence problem of an HCS of a graph or multigraph Γ as above which is both cyclic and symmetric. In this paper, we completely solve this problem: in the case of even order, the final answer is that cyclicity and symmetry can always cohabit when a cyclic solution exists. On the other hand, imposing that a cyclic HCS of odd order is also symmetric is very restrictive; we prove in fact that an HCS of with both properties exists if and only if is a prime.
    Journal of Combinatorial Designs 09/2014; 22(9).
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    ABSTRACT: A -semiframe of type is a -GDD of type , , in which the collection of blocks can be written as a disjoint union where is partitioned into parallel classes of and is partitioned into holey parallel classes, each holey parallel class being a partition of for some . A -SF is a -semiframe of type in which there are p parallel classes in and d holey parallel classes with respect to . In this paper, we shall show that there exists a (3, 1)-SF for any if and only if , , , and .
    Journal of Combinatorial Designs 08/2014;
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    ABSTRACT: 2-(v,k,1) designs admitting a primitive rank 3 automorphism group , where G0 belongs to the Extraspecial Class, or to the Exceptional Class of Liebeck's Theorem in [23], are classified.
    Journal of Combinatorial Designs 08/2014;
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    ABSTRACT: Latin hypercube designs have been found very useful for designing computer experiments. In recent years, several methods of constructing orthogonal Latin hypercube designs have been proposed in the literature. In this article, we report some more results on the construction of orthogonal Latin hypercubes which result in several new designs.
    Journal of Combinatorial Designs 08/2014;
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    ABSTRACT: Symmetric orthogonal arrays and mixed orthogonal arrays are useful in the design of various experiments. They are also a fundamental tool in the construction of various combinatorial configurations. In this paper, we investigated the mixed orthogonal arrays with four and five factors of strength two, and proved that the necessary conditions of such mixed orthogonal arrays are also sufficient with several exceptions and one possible exception.
    Journal of Combinatorial Designs 08/2014; 22(8).
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    ABSTRACT: A G-design of order n is a decomposition of the complete graph on n vertices into edge-disjoint subgraphs isomorphic to G. Grooming uniform all-to-all traffic in optical ring networks with grooming ratio C requires the determination of graph decompositions of the complete graph on n vertices into subgraphs each having at most C edges. The drop cost of such a grooming is the total number of vertices of nonzero degree in these subgraphs, and the grooming is optimal when the drop cost is minimum. The existence spectrum problem of G-designs for five-vertex graphs is a long standing problem posed by Bermond, Huang, Rosa and Sotteau in 1980, which is closely related to traffic groomings in optical networks. Although considerable progress has been made over the past 30 years, the existence problems for such G-designs and their related traffic groomings in optical networks are far from complete. In this paper, we first give a complete solution to this spectrum problem for five-vertex graphs by eliminating all the undetermined possible exceptions. Then, we determine almost completely the minimum drop cost of 8-groomings for all orders n by reducing the 37 possible exceptions to 8. Finally, we show the minimum possible drop cost of 9-groomings for all orders n is realizable with 14 exceptions and 12 possible exceptions.
    Journal of Combinatorial Designs 07/2014;
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    ABSTRACT: A q-ary code of length n, size M, and minimum distance d is called an code. An code with is said to be maximum distance separable (MDS). Here one-error-correcting () MDS codes are classified for small alphabets. In particular, it is shown that there are unique (5, 53, 3)5 and (5, 73, 3)7 codes and equivalence classes of (5, 83, 3)8 codes. The codes are equivalent to certain pairs of mutually orthogonal Latin cubes of order q, called Graeco-Latin cubes.
    Journal of Combinatorial Designs 06/2014;
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    ABSTRACT: A 1-factorization of a graph G is a decomposition of G into edge-disjoint 1-factors (perfect matchings), and a perfect 1-factorization is a 1-factorization in which the union of any two of the 1-factors is a Hamilton cycle. We consider the problem of the existence of perfect 1-factorizations of even order 4-regular Cayley graphs, with a particular interest in circulant graphs. In this paper, we study a new family of graphs, denoted , which are Cayley graphs if and only if k is even or . By solving the perfect 1-factorization problem for a large class of graphs, we obtain a new class of 4-regular bipartite circulant graphs that do not have a perfect 1-factorization, answering a problem posed in [7]. With further study of graphs, we prove the nonexistence of P1Fs in a class of 4-regular non-bipartite circulant graphs, which is further support for a conjecture made in [7].
    Journal of Combinatorial Designs 06/2014;
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    ABSTRACT: Intersection numbers for subspace designs are introduced and $q$-analogs of the Mendelsohn and K\"ohler equations are given. As an application, we are able to determine the intersection structure of a putative $q$-analog of the Fano plane for any prime power $q$. It is shown that its existence implies the existence of a $2$-$(7,3,q^4)_q$ subspace design. Furthermore, several simplified or alternative proofs concerning intersection numbers of ordinary block designs are discussed.
    Journal of Combinatorial Designs 05/2014;
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    ABSTRACT: Squashed 6-cycle systems are introduced as a natural counterpart to 2-perfect 6-cycle systems. The spectrum for the latter has been determined previously in [5]. We determine completely the spectrum for squashed 6-cycle systems, and also for squashed 6-cycle packings.
    Journal of Combinatorial Designs 05/2014; 22(5).
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    ABSTRACT: A k-cycle system of a multigraph G is an ordered pair (V, C) where V is the vertex set of G and C is a set of k-cycles, the edges of which partition the edges of G. A k-cycle system of is known as a λ-fold k-cycle system of order V. A k-cycle system of (V, C) is said to be enclosed in a k-cycle system of if and . We settle the difficult enclosing problem for λ-fold 5-cycle systems with u = 1.
    Journal of Combinatorial Designs 05/2014; 22(5).
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    ABSTRACT: Every abelian group of even order with a noncyclic Sylow 2-subgroup is known to be R-sequenceable except possibly when the Sylow 2-subgroup has order 8. We construct an R-sequencing for many groups with elementary abelian Sylow 2-subgroups of order 8 and use this to show that all such groups of order other than 8 also have terraces. This completes the proof of Bailey's Conjecture in the abelian case: all abelian groups other than the noncyclic elementary abelian 2-groups have terraces. For odd orders it is known that abelian groups are R-sequenceable except possibly those with noncyclic Sylow 3-subgroups. We show how the theory of narcissistic terraces can be exploited to find R-sequencings for many such groups, including infinitely many groups with each possible of Sylow 3-subgroup type of exponent at most 312and all groups whose Sylow 3-subgroups are of the form or .
    Journal of Combinatorial Designs 05/2014;
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    ABSTRACT: In recent years, several methods have been proposed for constructing -optimal and minimax-optimal supersaturated designs (SSDs). However, until now the enumeration problem of such designs has not been yet considered. In this paper, -optimal and minimax-optimal k-circulant SSDs with 6, 10, 14, 18, 22, and 26 runs, factors and are enumerated in a computer search. We have also enumerated all -optimal and minimax-optimal k-circulant SSDs with (mod 4) and . The computer search utilizes the fact that theses designs are equivalent to certain 1-rotational resolvable balanced incomplete block designs. Combinatorial properties of these resolvable designs are used to restrict the search space.
    Journal of Combinatorial Designs 04/2014; 22(4).
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    ABSTRACT: A cross-free set of size m in a Steiner triple system is three pairwise disjoint m-element subsets such that no intersects all the three -s. We conjecture that for every admissible n there is an STS(n) with a cross-free set of size which if true, is best possible. We prove this conjecture for the case , constructing an STS containing a cross-free set of size 6k. We note that some of the 3-bichromatic STSs, constructed by Colbourn, Dinitz, and Rosa, have cross-free sets of size close to 6k (but cannot have size exactly 6k). The constructed STS shows that equality is possible for in the following result: in every 3-coloring of the blocks of any Steiner triple system STS(n) there is a monochromatic connected component of size at least (we conjecture that equality holds for every admissible n). The analog problem can be asked for r-colorings as well, if and is a prime power, we show that the answer is the same as in case of complete graphs: in every r-coloring of the blocks of any STS(n), there is a monochromatic connected component with at least points, and this is sharp for infinitely many n.
    Journal of Combinatorial Designs 04/2014;
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    ABSTRACT: A k-star is the complete bipartite graph . Let G and H be graphs, and let be a partial H-decomposition of G. A partial H-decomposition, , of another graph is called an embedding of provided that and G is a subgraph of . We find an embedding of a partial k-star decomposition of into a k-star decomposition of , where s is at most if k is odd, and if k is even.
    Journal of Combinatorial Designs 04/2014; 22(4).
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    ABSTRACT: It is known that extremal ternary self-dual codes of length mod 12) yield 5-designs. Previously, mutually disjoint 5-designs were constructed by using single known generator matrix of bordered double circulant ternary self-dual codes (see [1, 2]). In this paper, a number of generator matrices of bordered double circulant extremal ternary self-dual codes are searched with the aid of computer. Using these codes we give many mutually disjoint 5-designs. As a consequence, a list of 5-spontaneous emission error designs are obtained.
    Journal of Combinatorial Designs 03/2014;

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