A Fast Direct Sampling Algorithm for Equilateral Closed Polygons

Sampling equilateral closed polygons is of interest in the statistical study of ring polymers. Over the past 30 years, previous authors have proposed a variety of simple Markov chain algorithms (but have not been able to show that they converge to the correct probability distribution) and complicated direct samplers (which require extended-precision arithmetic to evaluate numerically unstable polynomials). We present a simple direct sampler which is fast and numerically stable, and analyze its runtime using a new formula for the volume of equilateral polygon space as a Dirichlet-type integral.Comment: 10 pages, 2 figures. Added Duplantier as coauthor; we now give the precise asymptotic complexity of the algorith

Occluded iris classification and segmentation using self-customized artificial intelligence models and iterative randomized Hough transform

A fast and accurate iris recognition system is presented for noisy iris images, mainly the noises due to eye occlusion and from specular reflection. The proposed recognition system will adopt a self-customized support vector machine (SVM) and convolution neural network (CNN) classification models, where the models are built according to the iris texture GLCM and automated deep features datasets that are extracted exclusively from each subject individually. The image processing techniques used were optimized, whether the processing of iris region segmentation using iterative randomized Hough transform (IRHT), or the processing of the classification, where few significant features are considered, based on singular value decomposition (SVD) analysis, for testing the moving window matrix class if it is iris or non-iris. The iris segments matching techniques are optimized by extracting, first, the largest parallel-axis rectangle inscribed in the classified occluded-iris binary image, where its corresponding iris region is crosscorrelated with the same subject’s iris reference image for obtaining the most correlated iris segments in the two eye images. Finally, calculating the iriscode Hamming distance of the two most correlated segments to identify the subject’s unique iris pattern with high accuracy, security, and reliability

Potential of deep learning segmentation for the extraction of archaeological features from historical map series

Historical maps present a unique depiction of past landscapes, providing evidence for a wide range of information such as settlement distribution, past land use, natural resources, transport networks, toponymy and other natural and cultural data within an explicitly spatial context. Maps produced before the expansion of large‐scale mechanized agriculture reflect a landscape that is lost today. Of particular interest to us is the great quantity of archaeologically relevant information that these maps recorded, both deliberately and incidentally. Despite the importance of the information they contain, researchers have only recently begun to automatically digitize and extract data from such maps as coherent information, rather than manually examine a raster image. However, these new approaches have focused on specific types of information that cannot be used directly for archaeological or heritage purposes. This paper provides a proof of concept of the application of deep learning techniques to extract archaeological information from historical maps in an automated manner. Early twentieth century colonial map series have been chosen, as they provide enough time depth to avoid many recent large‐scale landscape modifications and cover very large areas (comprising several countries). The use of common symbology and conventions enhance the applicability of the method. The results show deep learning to be an efficient tool for the recovery of georeferenced, archaeologically relevant information that is represented as conventional signs, line‐drawings and text in historical maps. The method can provide excellent results when an adequate training dataset has been gathered and is therefore at its best when applied to the large map series that can supply such information. The deep learning approaches described here open up the possibility to map sites and features across entire map series much more quickly and coherently than other available methods, opening up the potential to reconstruct archaeological landscapes at continental scales

Folded Paper Geometry from 2D Pattern and 3D Contour

International audienceFolded paper exhibits very characteristic shapes, due to the presence of sharp folds and to exact isometry with a given planar pattern. Therefore, none of the physically-based simulators developed so far can handle paper-like material. We propose a purely geometric solution to generate static folded paper geometry from a 2D pattern and a 3D placement of its contour curve. Fold lines are explicitly identified and used to control a recursive, local subdivision process, leading to an efficient procedural modeling of the surface through a fold-aligned mesh. Contrary to previous work, our method generates paper-like surfaces with sharp creases while maintaining approximate isometry with the input pattern

Amenazas ideológicas en Uzbekistán: historia reciente y técnicas modernas

This article focuses on an approach to the history of relations between religion and the state in Uzbekistan and how the tense relationship has influenced the progress of Uzbekistan's independence. The research uses historical, comparative, deductive, and systematic methods of analysis. The discussions show that as a result of the obstacles to obtaining religious education in Uzbekistan during the Russian Empire and the Soviet Union, the spiritual and religious needs of many people were met with very limited notions, which have led to greater religious ignorance and pseudoscience that ultimately played a major role in activating extremist religious movements after 1991.El presente artículo se centra en un enfoque de la historia de las relaciones entre la religión y el Estado en Uzbekistán y en la forma en que la tensa relación ha influido en el progreso de la independencia de Uzbekistán. La investigación utiliza métodos de análisis históricos, comparativos, deductivos y sistemáticos. Los debates muestran que, como resultado de los obstáculos para obtener educación religiosa en Uzbekistán durante el Imperio Ruso y la Unión Soviética, las necesidades espirituales y religiosas de muchas personas fueron atendidas con nociones muy limitadas, lo que ha dado lugar a una mayor ignorancia religiosa y pseudociencia que, en última instancia, desempeñó un papel importante en la activación de los movimientos religiosos islamistas extremistas en el siglo XXI

Amenazas ideológicas en Uzbekistán: historia reciente y técnicas modernas

This article focuses on an approach to the history of relations between religion and the state in Uzbekistan and how the tense relationship has influenced the progress of Uzbekistan's independence. The research uses historical, comparative, deductive, and systematic methods of analysis. The discussions show that as a result of the obstacles to obtaining religious education in Uzbekistan during the Russian Empire and the Soviet Union, the spiritual and religious needs of many people were met with very limited notions, which have led to greater religious ignorance and pseudoscience that ultimately played a major role in activating extremist religious movements after 1991.El presente artículo se centra en un enfoque de la historia de las relaciones entre la religión y el Estado en Uzbekistán y en la forma en que la tensa relación ha influido en el progreso de la independencia de Uzbekistán. La investigación utiliza métodos de análisis históricos, comparativos, deductivos y sistemáticos. Los debates muestran que, como resultado de los obstáculos para obtener educación religiosa en Uzbekistán durante el Imperio Ruso y la Unión Soviética, las necesidades espirituales y religiosas de muchas personas fueron atendidas con nociones muy limitadas, lo que ha dado lugar a una mayor ignorancia religiosa y pseudociencia que, en última instancia, desempeñó un papel importante en la activación de los movimientos religiosos islamistas extremistas en el siglo XXI

Amenazas ideológicas en Uzbekistán: historia reciente y técnicas modernas

This article focuses on an approach to the history of relations between religion and the state in Uzbekistan and how the tense relationship has influenced the progress of Uzbekistan's independence. The research uses historical, comparative, deductive, and systematic methods of analysis. The discussions show that as a result of the obstacles to obtaining religious education in Uzbekistan during the Russian Empire and the Soviet Union, the spiritual and religious needs of many people were met with very limited notions, which have led to greater religious ignorance and pseudoscience that ultimately played a major role in activating extremist religious movements after 1991.El presente artículo se centra en un enfoque de la historia de las relaciones entre la religión y el Estado en Uzbekistán y en la forma en que la tensa relación ha influido en el progreso de la independencia de Uzbekistán. La investigación utiliza métodos de análisis históricos, comparativos, deductivos y sistemáticos. Los debates muestran que, como resultado de los obstáculos para obtener educación religiosa en Uzbekistán durante el Imperio Ruso y la Unión Soviética, las necesidades espirituales y religiosas de muchas personas fueron atendidas con nociones muy limitadas, lo que ha dado lugar a una mayor ignorancia religiosa y pseudociencia que, en última instancia, desempeñó un papel importante en la activación de los movimientos religiosos islamistas extremistas en el siglo XXI

Evolutionary origin of the nervous system from Ctenophora prospective

Nervous system is one of the key adaptations underlying the evolutionary success of the majority of animal groups. Ctenophores (or comb jellies) are gelatinous marine invertebrates that were probably the first lineage to diverge from the rest of animals. Due to the key phylogenetic position and multiple unique adaptations, the noncentralized nervous system of comb jellies has been in the center of the debate around the origin of the nervous system in the animal kingdom and whether it happened only once or twice. Here, we discuss the latest findings in ctenophore neuroscience and multiple challenges on the way to build a clear evolutionary picture of the origin of the nervous system

Sex hormonal modulation of hemispheric asymmetry and interhemispheric crosstalk

Fluctuating levels of sex hormones (estrogen, E and progesterone, P) during the menstrual cycle have been shown to affect fundamental principles of brain organization, that is functional cerebral asymmetries (FCAs). Regarding a possible underlying mechanism, it seems likely that dynamics in FCAs are driven by hormonal modulations of interhemispheric crosstalk (i.e., interhemispheric inhibition). Whether other aspects of interhemispheric interaction, such as interhemispheric integration (IHI), are also susceptible to menstrual cycle-related hormonal changes has not yet been examined. Moreover, most of the findings come from studies investigating younger women during hormonal distinct cycle phases. This approach, however, does not allow conclusions about causal relationships between hormonal changes and functional brain organization. It seems, thus, necessary to directly manipulate the hormonal status of participants via exogenous hormone therapy (HT).The present thesis focused on sex hormonal changes in IHI and FCAs in normally cycling women and postmenopausal women with and without HT. Younger women were tested twice, once during the low-hormone menstrual phase and once during the high-P luteal phase. Postmenopausal women were tested in a between-participants design differentiating between postmenopausal women using E therapy (ET), those using E plus synthetic progestins, and postmenopausal controls without HT. The results show that IHI in normally cycling women fluctuates across the menstrual cycle with an enhanced interhemispheric processing during the luteal phase. Thus, it seems that aspects of interhemispheric interaction (i.e., IHI) other than those involved in FCAs are also affected by the menstrual cycle and cycle-related hormonal changes. In contrast, HT, and ET in particular, after the menopause seems to affect intrahemispheric processing whereas intrahemispheric was essentially unaffected by HT. A modulation of intrahemispheric functioning (i.e. right hemisphere functioning) which was related to estradiol-levels also became evident when postmenopausal women were tested on a right hemisphere dominated asymmetry task. The findings can be explained by a faster and more pronounced age-related decline in interhemispheric relative to intrahemispheric processing which seems to be accompanied by a higher sensitivity to HT. Aging processes together with differences in the hormonal status (exogenous changes as a result of HT vs. endogenous changes during the menstrual cycle) may also explain divergent behavioural outcomes in postmenopausal women and younger women. Taken together, the findings show that the female brain retains its plasticity even after reproductive ages and remains susceptible to the effects of sex hormones throughout lifetime