What role do personal values play in the practice of economists? By means of a survey among economists working inside and outside academia in the Netherlands we present novel insights into their personal value structure, how they differ from the average citizen, and how it impacts their economic...

This article uses a sequentialized experimental design to select simulation input combinations for global optimization, based on Kriging (also called Gaussian process or spatial correlation modeling); this Kriging is used to analyze the input/output data of the simulation model (computer code)....

The aim of this paper is to quantify the benefit of demand and inventory smoothing in contrasting the extreme volatility and impetuous alteration of the market produced by the current economic recession. To do so we model a traditional supply chain and we test five settings of order smoothing...

In practice, simulation analysts often change only one factor at a time, and use graphical analysis of the resulting Input/Output (I/O) data. Statistical theory proves that more information is obtained when applying Design Of Experiments (DOE) and linear regression analysis. Unfortunately,...

A divisible design graph is a graph whose adjacency matrix is the incidence matrix of a divisible design. These graphs are a natural generalization of (v, k, ⋋)-graphs. In this paper we develop some theory, find many parameter conditions and give several constructions

We construct graphs that are cospectral but nonisomorphic with Kneser graphs K(n, k), when n =3k - 1, k> 2 and for infinitely many other pairs (n, k). We also prove that for 3 ≤ k ≤ n - 3 the Modulo-2 Kneser graph K2(n, k) is not determined by the spectrum

This paper presents a novel heuristic for constrained optimization of random computer simulation models, in which one of the simulation outputs is selected as the objective to be minimized while the other outputs need to satisfy prespecified target values. Besides the simulation outputs, the...

Using results on Hadamard difference sets, we construct regular graphical Hadamard matrices of negative type of order 4m^4 for every positive integer m. If m is greater than 1, such a Hadamard matrix is equivalent to a strongly regular graph with parameters (4m^4, 2m^4 + m^2, m^4 + m^2, m^4 +...

We determine a lower bound for the spectral radius of a graph in terms of the number of vertices and the diameter of the graph. For the specific case of graphs with diameter three we give a slightly better bound. We also construct families of graphs with small spectral radius, thus obtaining...

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...