This paper presents an investigation of a simple generic hyper-heuristic approach upon a set of widely used constructive heuristics (graph coloring heuristics) in timetabling. Within the hyperheuristic framework, a Tabu Search approach is employed to search for permutations of graph heuristics which are used for constructing timetables in exam and course timetabling problems. This underpins a m...

Assume that n and k are positive integers with n ≥ 2k + 1. A non-hamiltonian graph G is hypo hamiltonian if G − v is hamiltonian for any v ∈ V (G). It is proved that the generalized Petersen graph P (n, k) is hypo hamiltonian if and only if k = 2 and n ≡ 5 (mod 6). Similarly, a hamiltonian graph G is hyper hamiltonian if G−v is hamiltonian for any v ∈ V (G). In this paper, we will give some nec...

The order-(m, n) hyper-deBruijn graph HD(m,n) is the direct product of an order-m hypercube and an order-n debruijn graph. The hyper-deBruijn graph offers flexibility in terms of connections per node and the level of fault-tolerance. These networks as well possess logarithmic diameter, simple routing algorithms and support many computationally important subgraphs and admit efficient implementat...

The order-(m,n) hyper-deBruijn graph H D ( m , n) is the direct product of an order-m hypercube and an order-n debruijn graph. The hyper-deBruijn graph offers flexibility in terms of connections per node and the level of fault-tolerance. These networks as well possess logarithmic diameter, simple routing algorithms and support many computationally imponant subgraphs and admit efficient implemen...

In this paper, the Hyper - Zagreb index of the Cartesian product, composition and corona product of graphs are computed. These corrects some errors in G. H. Shirdel et al.[11].

A star-factor of a graph G is a spanning subgraph of G such that each of its component is a star. Clearly, every graph without isolated vertices has a star factor. A graph G is called star-uniform if all star-factors of G have the same number of components. To characterize star-uniform graphs was an open problem posed by Hartnell and Rall, which is motivated by the minimum cost spanning tree an...

We report the discovery of an unbound hyper-velocity star, US 708, in the Milky Way halo, with a heliocentric radial velocity of +708±15 km s −1. A quantitative NLTE model atmosphere analysis of optical spectra obtained with LRIS at the Keck I telescope shows that US 708 is an extremely helium-rich (N He /N H =10) subluminous O type star with T eff = 44 500 K, log g = 5.23 at a distance of 19 k...

Star networks have been recently proposed as attractive alternatives to the popular hyper-cube for interconnecting processors on a parallel computer. In this paper, we present an eecient algorithm that constructs an optimal parallel routing in star networks. Our result improves previous results for the problem.