Clapper-Yule Model

2016 ◽  
pp. 221-228
Author(s):  
Mathieu Hébert
Keyword(s):  
Yule Model

scholarly journals Exact formulas for the variance of several balance indices under the Yule model

2012 ◽  
Vol 67 (6-7) ◽  
pp. 1833-1846 ◽  
Author(s):  
Gabriel Cardona ◽  
Arnau Mir ◽  
Francesc Rosselló
Keyword(s):  
Yule Model

Improving Clapper–Yule model of the reflectance prediction by the path branching factor depending on the screen frequency of color halftone imaging

Optik ◽  
2014 ◽  
Vol 125 (20) ◽  
pp. 6242-6244 ◽  
Author(s):  
Neng Ke ◽  
Xiaomin He ◽  
Ying Wang ◽  
Yixin Zhang
Keyword(s):  
Yule Model ◽  
Branching Factor

Patterns of spermatophore distribution in Euchaeta norvegica: a further analysis

1979 ◽  
Vol 59 (2) ◽  
pp. 369-371 ◽  
Author(s):  
Tore Schweder
Keyword(s):  
Poisson Distribution ◽  
Frequency Distribution ◽  
Breeding Biology ◽  
Model Based ◽  
Yule Model

In a study of the breeding biology of Euchaeta norvegica (Boeck), Hopkins & Machin (1977) analysed the placement and frequency distribution of spermatophores on females. They found the number of spermatophores on sampled females to be underdispersed relative to the Poisson distribution and concluded that ‘virgin’ females are more attractive to males than females with spermatophores attached. They fitted the Greenwood & Yule (1920) model but drew no conclusions.The type of question which may be studied by fitting such a model is whether the attraction of males to ‘non-virgins’ is independent of the time since the first spermatophore was attached and also independent of the number of spermatophores already attached. This problem has been further investigated by fitting a version of the Greenwood & Yule model based on asynchronous recruitment of mature females. This version of the model is fully described in Schweder (1979); in this paper the results and biological implications are discussed.

Spectral Prediction Model for Halftone Prints by Enhanced Clapper-Yule Model

2012 ◽  
Vol 457-458 ◽  
pp. 1405-1408
Author(s):  
Tao Meng ◽  
Chun Mei Zhang ◽  
Mi Dan Li ◽  
Yi Xiao Song ◽  
Tai Sun ◽  
...  
Keyword(s):  
Prediction Model ◽  
Fluorescent Imaging ◽  
New Model ◽  
Color Separation ◽  
Extended Application ◽  
Yule Model ◽  
Dot Gain ◽  
The Way

The classical Clapper-Yule model and its improved models will both introduced the extended application which supports rough printing and halftone color fluorescent imaging. The characteristics of the new model were analyzed and the prospect of the Clapper-Yule mode was discussed. We proposed a new model, which was an enhancement of the classical Clapper-Yule model, which simulate optical dot gain of halftone prints by taking into account lateral scattering within the paper bulk and multiple internal reflections. The model we propose also takes into account the reflectance of inks at surface of the specific colors at specific rates. The model opens the way towards color separation of images to be reproduced. Several designs printed on an offset press demonstrate their applicability and their benefits.

scholarly journals On Sackin's original proposal: The variance of the leaves' depths as a phylogenetic balance index

2019 ◽  
Author(s):  
Tomás Martínez Coronado ◽  
Arnau Mir ◽  
Francesc Rossello ◽  
Lucía Rotger
Keyword(s):  
Phylogenetic Tree ◽  
Phylogenetic Trees ◽  
Rooted Tree ◽  
Rooted Trees ◽  
Closed Formula ◽  
Original Proposal ◽  
Yule Model ◽  
Uniform Model ◽  
Rooted Phylogenetic Tree ◽  
Balance Index

Abstract Background: The Sackin index S of a rooted phylogenetic tree, defined as the sum of its leaves' depths, is one of the most popular balance indices in phylogenetics, and Sackin's 1972 paper is usually cited as the source for this index. However, what Sackin actually proposed in his paper as a measure of the imbalance of a rooted tree was not the sum of its leaves' depths, but their "variation". This proposal was later implemented as the variance of the leaves' depths by Kirkpatrick and Slatkin, where moreover they posed the problem of finding a closed formula for its expected value under the Yule model. Nowadays, Sackin's original proposal seems to have passed into oblivion in the phylogenetics literature, replaced by the index bearing his name, which, in fact, was introduced a decade later by Sokal.Results: In this paper we study the properties of the variance of the leaves' depths, V, as a balance index. Firstly, we prove that the rooted trees with n leaves and maximum V value are exactly the combs with n leaves. But although V achieves its minimum value on every space BT_n of bifurcating rooted phylogenetic trees with n< 184 leaves at the so-called "maximally balanced trees" with n leaves, this property fails for almost every n>= 184. We provide then an algorithm that finds in O(n) time the trees in BT_n with minimum V value. Secondly, we obtain closed formulas for the expected V value of a bifurcating rooted tree with any number n of leaves under the Yule and the uniform models and, as a by-product of the computations leading to these formulas, we also obtain closed formulas for the variance of the Sackin index and the total cophenetic indexof a bifurcating rooted tree, as well as of their covariance, under the uniform model, thus filling this gap in the literature.Conclusions: The phylogenetics crowd has been wise in preferring as a balance index the sum S(T) of the leaves’ depths of a phylogenetic tree T over their variance V (T), because the latter does not seem to capture correctly the notion of balance of large bifurcating rooted trees. But for bifurcating trees up to 183 leaves, V is a valid and useful balance index.

Prediction Algorithm of Spectral Reflectance of Spot Color Ink Based on Color Parallel and Superposition Model

2012 ◽  
Vol 430-432 ◽  
pp. 1176-1182
Author(s):  
Chao Rong Lin ◽  
Jun Fei Xu ◽  
Jin Lin Xu
Keyword(s):  
Prediction Model ◽  
Spectral Reflectance ◽  
Difficult Problem ◽  
Current Paper ◽  
Prediction Algorithm ◽  
Superposition Model ◽  
Yule Model ◽  
Computational Difficulty ◽  
Color Prediction ◽  
Spot Color

Spectral prediction of spot color ink has always been a difficult problem in the field of color research. The current paper adopted color parallel and superposition models to deal with the Clapper-Yule model and to simplify the prediction model of spectral reflectance of spot color ink. respectively. Based on the experimental verification. the simplified method has a certain practical application value. and the spot color prediction of general presswork can meet the requirements fully. The most important consideration is that the simplification can largely reduce the computational difficulty. Moreover. the current paper compared the accuracy of color parallel model with the superposition model to simplify the spectral prediction model of spot color ink. The result showed that the color superposition model has higher accuracy in simplifying the spectral prediction model of spot color ink.

scholarly journals Group-based Yule model for bipartite author-paper networks

2005 ◽  
Vol 71 (2) ◽  
Author(s):  
Michel L. Goldstein ◽  
Steven A. Morris ◽  
Gary G. Yen
Keyword(s):  
Yule Model ◽  
Author Paper

scholarly journals Extending the Clapper–Yule model to rough printing supports

2005 ◽  
Vol 22 (9) ◽  
pp. 1952 ◽  
Author(s):  
Mathieu Hébert ◽  
Roger David Hersch
Keyword(s):  
Yule Model

scholarly journals On Sackin's original proposal: The variance of the leaves' depths as a phylogenetic balance index

2020 ◽  
Author(s):  
Tomás Martínez Coronado ◽  
Arnau Mir ◽  
Francesc Rossello ◽  
Lucía Rotger
Keyword(s):  
Phylogenetic Tree ◽  
Phylogenetic Trees ◽  
Rooted Tree ◽  
Rooted Trees ◽  
Closed Formula ◽  
Original Proposal ◽  
Yule Model ◽  
Uniform Model ◽  
Rooted Phylogenetic Tree ◽  
Balance Index

Abstract Background. The Sackin index S of a rooted phylogenetic tree, defined as the sum of its leaves' depths, is one of the most popular balance indices in phylogenetics, and Sackin's 1972 paper is usually cited as the source for this index. However, what Sackin actually proposed in his paper as a measure of the imbalance of a rooted tree was not the sum of its leaves' depths, but their ``variation''. This proposal was later implemented as the variance of the leaves' depths by Kirkpatrick and Slatkin in 1993, where they also posed the problem of finding a closed formula for its expected value under the Yule model. Nowadays, Sackin's original proposal seems to have passed into oblivion in the phylogenetics literature, replaced by the index bearing his name, which, in fact, was introduced a decade later by Sokal. Results. In this paper we study the properties of the variance of the leaves' depths, V, as a balance index. Firstly, we prove that the rooted trees with $n$ leaves and maximum V value are exactly the combs with n leaves. But although V achieves its minimum value on every space of bifurcating rooted phylogenetic trees with at most 183 leaves at the so-called ``maximally balanced trees'' with n leaves, this property fails for almost every n larger than 184 We provide then an algorithm that finds the bifurcating rooted trees with n leaves and minimum V value in quasilinear time. Secondly, we obtain closed formulas for the expected V value of a bifurcating rooted tree with any number n of leaves under the Yule and the uniform models and, as a by-product of the computations leading to these formulas, we also obtain closed formulas for the variance under the uniform model of the Sackin index and the total cophenetic index of a bifurcating rooted tree, as well as of their covariance, thus filling this gap in the literature.

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