Degree of Grey incidence is the parameter to describe the relationship between the factors. Many researchers have researched it and created several degree of grey incidence models. The simplest relation between the factors is linear correlation, so degree of grey incidence should measure linear correlation. This article calculates the degree of grey incidences by different models when the factors are linear correlative. And it is found that degree of grey incidence can not describe linear correlation very well. The result will be more accurate when the original sequences are dealt with by some operators before calculating. Distance and slope should be taken into account when create a new Grey Incidence Model.
Grey relational degree is the synthetic measure about the similarity of developing trend and the closing of the amount between two series.As an important part of the grey systems theory,grey relational analysis is the basis of the grey clustering analysis,grey decision-making and grey controlling.In this paper,we commented several kinds of grey relational models.We studied on the uniform and parallel properties of these grey relational models theoretically.We pointed out that some models satisfied to the uniform and parallel properties and others didn't.It is indicated that seldom model could satisfy this two properties in common.Therefore,it is meaningful to make the grey relation theory perfect and to construct new grey relational models.
Smartphones may be seen as miniature toolboxes to perform Physics experiments. In this paper, we present three different “optics workbenches" mainly based on the light meter of a smartphone. One is aimed at the precise study of Malus law and other effects associated to linearly polarized light, the second allows quantifying the light intensity distribution of diffraction or interference patterns projected on a screen, and the third demonstrates the so-called inverse square law obeyed by the light from a point-like source. These experiments allow to quantitatively demonstrate three fundamental laws of optics using quite inexpensive equipment.