Reliability Evaluation of Augmented Cubes on Degree

The [Formula: see text]-dimensional augmented cube [Formula: see text], proposed by Choudum and Sunitha in 2002, is one of the most famous interconnection networks of the distributed parallel system. Reliability evaluation of underlying topological structures is vital for fault tolerance analysis of this system. As one of the most extensively studied parameters, the [Formula: see text]-conditional edge-connectivity of a connected graph [Formula: see text], [Formula: see text], is defined as the minimum number of the cardinality of the edge-cut of [Formula: see text], if exists, whose removal disconnects this graph and keeps each component of [Formula: see text] having minimum degree at least [Formula: see text]. Let [Formula: see text], [Formula: see text] and [Formula: see text] be three integers, where [Formula: see text], if [Formula: see text] and [Formula: see text], if [Formula: see text]. In this paper, we determine the exact value of the [Formula: see text]-conditional edge-connectivity of [Formula: see text], [Formula: see text] for each positive integer [Formula: see text] and [Formula: see text], and give an affirmative answer to Shinde and Borse’s corresponding conjecture on this topic in [On edge-fault tolerance in augmented cubes, J. Interconnection Netw. 20(4) (2020), DOI:10.1142/S0219265920500139].

Constructing Node-Independent Spanning Trees in Augmented Cubes

For a network, edge/node-independent spanning trees (ISTs) can not only tolerate faulty edges/nodes, but also be used to distribute secure messages. As important node-symmetric variants of the hypercubes, the augmented cubes have received much attention from researchers. The n-dimensional augmented cube AQn is both (2n ‒ 1)-edge-connected and (2n ‒ 1)-nodeconnected (n ≢ 3), thus the well-known edge conjecture and node conjecture of ISTs are both interesting questions in AQn. So far, the edge conjecture on augmented cubes was proved to be true. However, the node conjecture on AQn is still open. In this paper, we further study the construction principle of the node-ISTs by using the double neighbors of every node in the higher dimension. We prove the existence of 2k − 1 node-ISTs rooted at node 0 in A Q n ( 00...0 ︸ n−k )(n≥k≥4) by proposing an ingenious way of construction and propose a corresponding O(NlogN) time algorithm, where N = 2k is the number of nodes in A Q n ( 00...0 ︸ n−k ) .

On Edge-Fault Tolerance in Augmented Cubes

The augmented cube AQn is one of the important variations of the hypercube Qn. In this paper, we prove that the conditional h-edge connectivity of AQn with n ≥ 3 is 8n − 16 for h = 3 and 2n for h = 2n − 3. We also obtain an upper bound on the conditional h-edge connectivity for odd integer h satisfying [Formula: see text].

Fault-Tolerant Maximal Local-Edge-Connectivity of Augmented Cubes

An interconnection network is usually modeled as a graph, in which vertices and edges correspond to processors and communication links, respectively. Connectivity is an important metric for fault tolerance of interconnection networks. A connected graph [Formula: see text] is said to be maximally local-edge-connected if each pair of vertices [Formula: see text] and [Formula: see text] of [Formula: see text] are connected by [Formula: see text] pairwise edge-disjoint paths. In this paper, we show that the [Formula: see text]-dimensional augmented cube [Formula: see text] is [Formula: see text]-edge-fault-tolerant maximally local-edge-connected and the bound [Formula: see text] is sharp; under the restricted condition that each vertex has at least three fault-free adjacent vertices, [Formula: see text] is [Formula: see text]-edge-fault-tolerant maximally local-edge-connected and the bound [Formula: see text] is sharp; and under the restricted condition that each vertex has at least [Formula: see text] fault-free adjacent vertices, [Formula: see text] is [Formula: see text]-edge-fault-tolerant maximally local-edge-connected. Furthermore, we show that a [Formula: see text]-regular graph [Formula: see text] is [Formula: see text]-fault-tolerant one-to-many maximally local-connected if [Formula: see text] does not contain [Formula: see text] and is super [Formula: see text]-vertex-connected of order 1, a [Formula: see text]-regular graph [Formula: see text] is [Formula: see text]-fault-tolerant one-to-many maximally local-connected if [Formula: see text] does not contain [Formula: see text] and is super [Formula: see text]-vertex-connected of order 1.

Fault-Tolerant Panconnectivity of Augmented Cubes AQn

The augmented cube [Formula: see text] is a variation of the hypercube [Formula: see text]. This paper considers the fault-tolerant Panconnectivity of [Formula: see text]. Assume that [Formula: see text] and [Formula: see text]. We prove that for any two fault-free vertices [Formula: see text] and [Formula: see text] with distance [Formula: see text] in [Formula: see text], there exists a fault-free path [Formula: see text] of each length from [Formula: see text] to [Formula: see text] in [Formula: see text] if [Formula: see text], where [Formula: see text] is the number of faulty vertices in [Formula: see text]. Moreover, the bound is sharp.

A Note on the Pessimistic Diagnosability of Augmented Cubes

A system is t/t-diagnosable if, provided the number of faulty processor is bounded by t, all faulty processors can be isolated within a set of size at most t with at most one fault-free node mistake as a faulty one. The pessimistic diagnosability of a system G, denoted by tp(G), is the maximal number of faulty processors so that the system G is t/t-diagnosable. The augmented cube AQn, proposed by Choudum and Sunitha [Networks 40 (2) (2002) 71–84], has many attractive properties such as regularity, strong connectivity and symmetry. In this paper, we determine the pessimistic diagnosability of the n-dimensional augmented cube AQn and prove that tp(AQn)=4n−8 for n≥5.

Design Techniques for the DNA Cubic-Lattice

We use the Watson-Crick properties of DNA and the principles of graph theory to construct origami folding designs for self-assembling cubic lattices. Our objective is a mathematical design strategy that can be expanded systematically to any size cubic lattice. This design consists of threading a scaffolding strand of DNA through the lattice that is secured in place by short staple strands of DNA. We first add augmenting edges to the cubic lattice to enable a single scaffolding strand threading. We then thread the scaffolding strand through the augmented cube in a way that minimizes the number of different vertex configurations in the structure. Key Words: Watson-Crick, DNA Self-Assembly, Origami folding, Cubic Lattice, Scaffolding Strand, Threading, Staple Strands