We give an overview of results on amorphic association schemes. We give the known constructions of such association schemes, and enumerate most such association schemes on up to 49 vertices. Special attention is paid to cyclotomic association schemes. We give several results on when a strongly...

We show that the Hamming graph H(3; q) with diameter three is uniquely determined by its spectrum for q is greater than or equal to 36. Moreover, we show that for given integer D greater than or equal to 2, any graph cospectral with the Hamming graph H(D, q) is locally the disjoint union of D...

In [E.R. van Dam and W.H. Haemers, Which graphs are determined by their spectrum?, Linear Algebra Appl. 373 (2003), 241-272] we gave a survey of answers to the question of which graphs are determined by the spectrum of some matrix associated to the graph. In particular, the usual adjacency...

We investigate minimax Latin hypercube designs in two dimensions for several distance measures. For the l-distance we are able to construct minimax Latin hypercube designs of n points, and to determine the minimal covering radius, for all n. For the l1-distance we have a lower bound for the...

In black box evaluation and optimization, Latin hypercube designs play an important role. When dealing with multiple black box functions, the need often arises to construct designs for all black boxes jointly, instead of individually. These so-called nested designs consist of two different...

We construct distance-regular graphs with the same-classical-parameters as the Grassman graphs on the e-dimensional subspaces of a (2e+1)-dimensional space over an arbitrary finite field. This provides the first known family of non-transitive distance-regular graphs with unbounded diameter

The design of computer experiments is an important step in black box evaluation and optimization processes. When dealing with multiple black box functions the need often arises to construct designs for all black boxes jointly, instead of individually. These so-called nested designs are used to...

In this and a sequel paper, we study combinatorial designs whose incidence matrix has two distinct singular values. These generalize 2-(v, k, lambda) designs, and include partial geometric designs and uniform multiplicative designs. Here, we study the latter, which are precisely the nonsingular...

In this and an earlier paper [17], we study combinatorial designs whose incidence matrix has two distinct singular values. These generalize (v, k, lambda) designs, and include uniform multiplicative designs and partial geometric designs. Here, we study the latter, which are precisely the designs...

This paper introduces methods to coordinate black box simulations in the construction of metamodels for situations in which we have to deal with coupled black boxes. We define three coordination methods: parallel simulation, sequential simulation and sequential modeling. To compare these three...