Multi-objective optimisation for receiver operating characteristic analysis

Copyright © 2006 Springer-Verlag Berlin Heidelberg. The final publication is available at link.springer.comBook title: Multi-Objective Machine LearningSummary Receiver operating characteristic (ROC) analysis is now a standard tool for the comparison of binary classifiers and the selection operating parameters when the costs of misclassification are unknown. This chapter outlines the use of evolutionary multi-objective optimisation techniques for ROC analysis, in both its traditional binary classification setting, and in the novel multi-class ROC situation. Methods for comparing classifier performance in the multi-class case, based on an analogue of the Gini coefficient, are described, which leads to a natural method of selecting the classifier operating point. Illustrations are given concerning synthetic data and an application to Short Term Conflict Alert

GLS-1, a Novel P Granule Component, Modulates a Network of Conserved RNA Regulators to Influence Germ Cell Fate Decisions

Post-transcriptional regulatory mechanisms are widely used to influence cell fate decisions in germ cells, early embryos, and neurons. Many conserved cytoplasmic RNA regulatory proteins associate with each other and assemble on target mRNAs, forming ribonucleoprotein (RNP) complexes, to control the mRNAs translational output. How these RNA regulatory networks are orchestrated during development to regulate cell fate decisions remains elusive. We addressed this problem by focusing on Caenorhabditis elegans germline development, an exemplar of post-transcriptional control mechanisms. Here, we report the discovery of GLS-1, a new factor required for many aspects of germline development, including the oocyte cell fate in hermaphrodites and germline survival. We find that GLS-1 is a cytoplasmic protein that localizes in germ cells dynamically to germplasm (P) granules. Furthermore, its functions depend on its ability to form a protein complex with the RNA-binding Bicaudal-C ortholog GLD-3, a translational activator and P granule component important for similar germ cell fate decisions. Based on genetic epistasis experiments and in vitro competition experiments, we suggest that GLS-1 releases FBF/Pumilio from GLD-3 repression. This facilitates the sperm-to-oocyte switch, as liberated FBF represses the translation of mRNAs encoding spermatogenesis-promoting factors. Our proposed molecular mechanism is based on the GLS-1 protein acting as a molecular mimic of FBF/Pumilio. Furthermore, we suggest that a maternal GLS-1/GLD-3 complex in early embryos promotes the expression of mRNAs encoding germline survival factors. Our work identifies GLS-1 as a fundamental regulator of germline development. GLS-1 directs germ cell fate decisions by modulating the availability and activity of a single translational network component, GLD-3. Hence, the elucidation of the mechanisms underlying GLS-1 functions provides a new example of how conserved machinery can be developmentally manipulated to influence cell fate decisions and tissue development

The endothelial glycocalyx: composition, functions, and visualization

This review aims at presenting state-of-the-art knowledge on the composition and functions of the endothelial glycocalyx. The endothelial glycocalyx is a network of membrane-bound proteoglycans and glycoproteins, covering the endothelium luminally. Both endothelium- and plasma-derived soluble molecules integrate into this mesh. Over the past decade, insight has been gained into the role of the glycocalyx in vascular physiology and pathology, including mechanotransduction, hemostasis, signaling, and blood cell–vessel wall interactions. The contribution of the glycocalyx to diabetes, ischemia/reperfusion, and atherosclerosis is also reviewed. Experimental data from the micro- and macrocirculation alludes at a vasculoprotective role for the glycocalyx. Assessing this possible role of the endothelial glycocalyx requires reliable visualization of this delicate layer, which is a great challenge. An overview is given of the various ways in which the endothelial glycocalyx has been visualized up to now, including first data from two-photon microscopic imaging

Physics-based rendering: Simulated Mueller matrix imaging

Physics-based rendering (PBR) engines attempt to generate photorealistic images by mimicking light-matter interaction in a physically plausible way. PBR has become the standard rendering method in the fields of animation, gaming, and computer graphics research. More recently, PBR engines have included the ability to track the full polarization state of light. An area of interest for polarization-Aware PBR engines is validating the accuracy of polarized bi-direction reflection distribution functions (pBRDF). pBRDFs are polarized material models described by a geometry-, texture-, and albedo-dependent Mueller matrix. For renderings, methods to analyze the pBRDF are limited. This work presents a pBRDF analysis method that simulates a Mueller matrix imaging polarimeter using a polarization-Aware PBR engine. Simulated reconstructed Mueller matrix images are qualitatively compared to measurements from a Mueller matrix imaging polarimeter. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Compression, interpolation, and importance sampling for polarized BRDF models

In this work, the KAIST Mueller measurement database is compressed by assuming a triply degeneracy (TD) in the Cloude coherency eigenspectrum. This assumption compresses the database by a factor of two by reparameterizes the database into eight parameters, maintains physicality when interpolated for non-measured geometries, and is shown to retain the dominant polarimetric properties for both diffuse and specular light-matter interactions. For each 4 × 4 Mueller matrix, the 8 TD parameters are: the radiometric average throughput, a depolarization parameter, and 6 parameters to describe the dominant coherent process. Polarimetric importance sampling is made possible by interpreting the eigenspectrum as probabilities. To evaluate the proposed methods, a sphere is rendered using the pink silicone material from the KAIST pBRDF database and compared to a TD compressed and polarimetric importance sampled pBRDF rendering. The average deviation in the polarizance angle and degree of linear polarization (AoLP and DoLP) deviation was 16.9° and 1.1% for both the TD compressed and polarimetric importance sampled pBRDF model as compared to the KAIST pBRDF model, respectively. The pBRDF models are also compared by rendering two scenes containing multiple surface interactions and several material types. Polarimetric importance sampling convergence and its dependence on the materials’ depolarization and ray depth are reported for these scenes. © 2022 Optica Publishing GroupOpen access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Media 2: Method for optimizing channelized quadratic observers for binary classification of large-dimensional image datasets

Originally published in JOSA A on 01 April 2015 (josaa-32-4-549

Media 1: Method for optimizing channelized quadratic observers for binary classification of large-dimensional image datasets

Originally published in JOSA A on 01 April 2015 (josaa-32-4-549