Circular data are commonly encountered in the earth sciences and statistical descriptions and inferences about such data are necessary in structural geology. In this paper we compare two statistical distributions appropriate for complex circular data sets: the mixture of von Mises and the projected normal distribution. We show how the number of components in a mixture of von Mises distribution ...

Most real systems are very complex and it is difficult to analyze and to improve their reliability. Large numbers of components and subsystems and their operating complexity cause that the evaluation of their reliability is complicated. As a rule these are series systems, parallel systems or “m out of n” systems composed of a large number of components. One of the important techniques for relia...

We compare conventional multiple-choice tests with so-called “liberal” multiple-choice tests, also known as “free-choice” tests, from a theoretical standpoint. The style of the questions is identical in these two alternative test formats, but in a liberal/free-choice test candidates may select as many options per question as they wish; the marking scheme penalises incorrect selections via negat...

Artificial neural networks are becoming increasingly popular as predictive statistical tools in ecosystem ecology and as models of signal processing in behavioural and evolutionary ecology. We demonstrate here that a commonly used network in ecology, the three-layer feed-forward network, trained with the backpropagation algorithm, can be extremely sensitive to the stochastic variation in traini...

Many children fail to master fraction arithmetic even after years of instruction, a failure that hinders their learning of more advanced mathematics as well as their occupational success. To test hypotheses about why children have so many difficulties in this area, we created a computational model of fraction arithmetic learning and presented it with the problems from a widely used textbook ser...

Adults combine different local motions to form a global percept of motion. This study explores the origins of this process by testing how perturbations of local motion influence infants' sensitivity to global motion. Infants at 6-, 12-, and 18-weeks of age viewed random dots moving with a gaussian distribution of dot directions defined by a mean of 0 degree (rightward) or 180 degrees (leftward)...

The authors identify 2 major types of statistical data from which semantic representations can be learned. These are denoted as experiential data and distributional data. Experiential data are derived by way of experience with the physical world and comprise the sensory-motor data obtained through sense receptors. Distributional data, by contrast, describe the statistical distribution of words ...

We analyze random walk through fractal environments, embedded in three-dimensional, permeable space. Particles travel freely and are scattered off into random directions when they hit the fractal. The statistical distribution of the flight increments (i.e., of the displacements between two consecutive hittings) is analytically derived from a common, practical definition of fractal dimension, an...

Stochastic noise is incorporated in the numerical simulation of weakly scattering random lasers, which qualitatively captures lasing phenomena that have been observed experimentally. We examine the behavior of the emission spectrum while pumping only part of the entire one-dimensional random system. A decrease in the density of lasing states is the dominant mechanism for observing discrete lasi...

Selection of service providers in supply chain is a critical decision that affects future performance of the chain. In practice, there are several factors to be considered in selection of proper service providers such as quality of transport, price, trustworthiness, and lead time. One of the main factors in selection of service providers is the time. In this paper, we investigate the effect of ...