Showing papers on "Centroid published in 1979"
TL;DR: In this paper, a centroid scaling technique is used to estimate multidimensional joint spaces from the pick-any data, where subjects are represented as points whose coordinates are proportional to the centroids of the points representing their choices.
Abstract: Social and naturally occurring choice phenomena are often of the “pick-any” type in which the number of choices made by a subject as well as the set of alternatives from which they are chosen is unconstrained. These data present a special analytical problem because the meaning of non-choice among pick-any choice data is always ambiguous: A non-chosen alternative may be either unacceptable, or acceptable but not considered, or acceptable and considered but not chosen. A model and scaling method for these data are introduced, allowing for this ambiguity of non-choice. Subjects are represented as points whose coordinates are proportional to the centroids of the points representing their choices. Alternatives are represented at points whose coordinates are proportional to the centroids of the points representing subjects who have chosen them. This centroid scaling technique estimates multidimensional joint spaces from the pick-any data.
70 citations
TL;DR: In this article, a computational study has been performed using several molecules and analytic curves to determine specific error limits which can be assigned to either a specific band strength, or in estimating the electronic transition moment using the r -centroid approximation.
Abstract: The r -centroid approximation, used in the analysis of intensity measurements of electronic band spectra of diatomic molecules, allows a separation of the band strength into a pure vibrational term (the Franck-Condon factor q v ′ v ″ ) and an electronic term [the electronic transition moment Re ( r )]. The r -centroid approximation is known to have limits to its applicability. However, no specific error limits have previously been given. A computational study has been performed using several molecules and analytic curves to determine specific error limits which can be assigned to either a specific band strength, or in estimating the electronic transition moment using the r -centroid approximation. Other techniques suggested for the evaluation of Re ( r ) have also been tested.
26 citations
TL;DR: The centroid, variance, eccentricity, and angle of the principal axes are suggested as pertinent parameters, and an image chopping technique for fast measurement of these parameters is described.
Abstract: In several applications it is necessary to get a fast evaluation of the shape and quality of an image of a point source. Since a complete description by means of the point spread function involves time-consuming data processing, it is necessary to limit the evaluation to a set of parameters which can be measured at high rates. Such a set can be defined in terms of the first and second moments of the distribution. In this article the centroid, variance, eccentricity, and angle of the principal axes are suggested as pertinent parameters, and an image chopping technique for fast measurement of these parameters is described.
12 citations