نتایج جستجو برای: divergence time estimation

تعداد نتایج: 2136009  

Journal: :J. Field Robotics 2018
Bas J. Pijnacker Hordijk Kirk Y. W. Scheper Guido C. H. E. de Croon

Small flying robots can perform landing maneuvers using bio-inspired optical flow by maintaining a constant divergence. However, optical flow is typically estimated from frame sequences recorded by standard miniature cameras. This requires processing full images on-board, limiting the update rate of divergence measurements, and thus the speed of the control loop and the robot. Event-based camer...

2009
Rudolf Kulhavý

The role of Kerridge inaccuracy, Shannon entropy and Kullback-Leibler distance in statistical estimation is shown for both dicrete and continuous observations. The cases of data independence and regression-type dependence are considered in parallel. Pythagorean-like relations valid for probability distributions are presented and their importance for estimation under compressed data is indicated.

Journal: :CoRR 2006
Ambedkar Dukkipati

Kullback-Leibler relative-entropy, in cases involving distributions resulting from relative-entropy minimization, has a celebrated property reminiscent of squared Euclidean distance: it satisfies an analogue of the Pythagoras’ theorem. And hence, this property is referred to as Pythagoras’ theorem of relative-entropy minimization or triangle equality and plays a fundamental role in geometrical ...

2014
Beatriz Mello Carlos G Schrago

Divergence time estimation has become an essential tool for understanding macroevolutionary events. Molecular dating aims to obtain reliable inferences, which, within a statistical framework, means jointly increasing the accuracy and precision of estimates. Bayesian dating methods exhibit the propriety of a linear relationship between uncertainty and estimated divergence dates. This relationshi...

Journal: Mycologia Iranica 2017

Studies on the evolutionary history of ascomycetes in terms of time scale will help to understand historical patterns that shape their biodiversity. Until now most of dating studies of ascomycetes have focused on major events in fungal evolution but not on divergence events within smaller groups of fungi e.g. within Sordariomycetes. We used molecular dating to estimate the time of separation of...

2014
Septimia Sarbu

Shannon and Rényi information theory have been applied to coupling estimation in complex systems using time series of their dynamical states. By analysing how information is transferred between constituent parts of a complex system, it is possible to infer the coupling parameters of the system. To this end, we introduce the partial Rényi transfer entropy and we give an alternative derivation of...

2010
Arthur U. Asuncion Qiang Liu Alexander T. Ihler Padhraic Smyth

Composite likelihood methods provide a wide spectrum of computationally efficient techniques for statistical tasks such as parameter estimation and model selection. In this paper, we present a formal connection between the optimization of composite likelihoods and the well-known contrastive divergence algorithm. In particular, we show that composite likelihoods can be stochastically optimized b...

2012
Masashi Sugiyama Taiji Suzuki Takafumi Kanamori

Estimation of the ratio of probability densities has attracted a great deal of attention since it can be used for addressing various statistical paradigms. A naive approach to density-ratio approximation is to first estimate numerator and denominator densities separately and then take their ratio. However, this two-step approach does not perform well in practice, and methods for directly estima...

Journal: :Molecular biology and evolution 2014
Heidi E L Lischer Laurent Excoffier Gerald Heckel

Phylogenetic reconstruction of the evolutionary history of closely related organisms may be difficult because of the presence of unsorted lineages and of a relatively high proportion of heterozygous sites that are usually not handled well by phylogenetic programs. Genomic data may provide enough fixed polymorphisms to resolve phylogenetic trees, but the diploid nature of sequence data remains a...

2010
ANNIKA M. MOE GEORGE D. WEIBLEN

Speciation in pollinating seed predators such as Þg wasps (Hymenoptera: Agaonidae) is likely to have been inßuenced by a combination of ecological and geographical isolating mechanisms, but recentmolecular analyses of Þgwasps have focused on pollinator specialization as themain factor driving speciation. This study investigates the contribution of geographic modes of speciation such as dispersa...

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