Hyperparameter Importance Across Datasets

With the advent of automated machine learning, automated hyperparameter optimization methods are by now routinely used in data mining. However, this progress is not yet matched by equal progress on automatic analyses that yield information beyond performance-optimizing hyperparameter settings. In this work, we aim to answer the following two questions: Given an algorithm, what are generally its most important hyperparameters, and what are typically good values for these? We present methodology and a framework to answer these questions based on meta-learning across many datasets. We apply this methodology using the experimental meta-data available on OpenML to determine the most important hyperparameters of support vector machines, random forests and Adaboost, and to infer priors for all their hyperparameters. The results, obtained fully automatically, provide a quantitative basis to focus efforts in both manual algorithm design and in automated hyperparameter optimization. The conducted experiments confirm that the hyperparameters selected by the proposed method are indeed the most important ones and that the obtained priors also lead to statistically significant improvements in hyperparameter optimization.Comment: \c{opyright} 2018. Copyright is held by the owner/author(s). Publication rights licensed to ACM. This is the author's version of the work. It is posted here for your personal use, not for redistribution. The definitive Version of Record was published in Proceedings of the 24th ACM SIGKDD International Conference on Knowledge Discovery & Data Minin

Implicit learning of temporal behavior in complex dynamic environments

Humans can automatically detect and learn to exploit repeated aspects (regularities) of the environment. Timing research suggests that such learning is not only used to anticipate what will happen, but also when it will happen. However, in timing experiments, the intervals to be timed are presented in isolation from other stimuli and explicitly cued, contrasting with naturalistic environments in which intervals are embedded in a constant stream of events and individuals are hardly aware of them. It is unclear whether laboratory findings from timing research translate to a more ecologically valid, implicit environment. Here we show in a game-like experiment, specifically designed to measure naturalistic behavior, that participants implicitly use regular intervals to anticipate future events, even when these intervals are constantly interrupted by irregular yet behaviorally relevant events. This finding extends previous research by showing that individuals not only detect such regularities but can also use this knowledge to decide when to act in a complex environment. Furthermore, this finding demonstrates that this type of learning can occur independently from the ordinal sequence of motor actions, which contrasts this work with earlier motor learning studies. Taken together, our results demonstrate that regularities in the time between events are implicitly monitored and used to predict and act on what happens when, thereby showing that laboratory findings from timing research can generalize to naturalistic environments. Additionally, with the development of our game-like experiment, we demonstrate an approach to test cognitive theories in less controlled, ecologically more valid environments

Practical sand transport formula for non-breaking waves and currents

Open Access funded by Engineering and Physical Sciences Research Council Under a Creative Commons license Acknowledgements This work is part of the SANTOSS project (‘SANd Transport in OScillatory flows in the Sheet-flow regime’) funded by the UK's EPSRC (GR/T28089/01) and STW in The Netherlands (TCB.6586). JW acknowledges Deltares strategic research funding under project number 1202359.09. Richard Soulsby is gratefully acknowledged for valuable discussions and feedback on the formula during the SANTOSS project.Peer reviewedPostprin

Unique behavioral and neurochemical effects induced by repeated adolescent consumption of caffeine-mixed alcohol in C57BL/6 mice.

The number of highly caffeinated products has increased dramatically in the past few years. Among these products, highly caffeinated energy drinks are the most heavily advertised and purchased, which has resulted in increased incidences of co-consumption of energy drinks with alcohol. Despite the growing number of adolescents and young adults reporting caffeine-mixed alcohol use, knowledge of the potential consequences associated with co-consumption has been limited to survey-based results and in-laboratory human behavioral testing. Here, we investigate the effect of repeated adolescent (post-natal days P35-61) exposure to caffeine-mixed alcohol in C57BL/6 mice on common drug-related behaviors such as locomotor sensitivity, drug reward and cross-sensitivity, and natural reward. To determine changes in neurological activity resulting from adolescent exposure, we monitored changes in expression of the transcription factor ΔFosB in the dopaminergic reward pathway as a sign of long-term increases in neuronal activity. Repeated adolescent exposure to caffeine-mixed alcohol exposure induced significant locomotor sensitization, desensitized cocaine conditioned place preference, decreased cocaine locomotor cross-sensitivity, and increased natural reward consumption. We also observed increased accumulation of ΔFosB in the nucleus accumbens following repeated adolescent caffeine-mixed alcohol exposure compared to alcohol or caffeine alone. Using our exposure model, we found that repeated exposure to caffeine-mixed alcohol during adolescence causes unique behavioral and neurochemical effects not observed in mice exposed to caffeine or alcohol alone. Based on similar findings for different substances of abuse, it is possible that repeated exposure to caffeine-mixed alcohol during adolescence could potentially alter or escalate future substance abuse as means to compensate for these behavioral and neurochemical alterations. © 2016 Robins et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Моделі динаміки пружних збурень у неоднорідно деформованому континуумі

Розвинуто нелінійну теорію пружності стосовно задач томографії тензорних полів у неоднорідно деформованих твердих тілах. За визначальні параметри локального термодинамічного стану, що відповідають процесові деформування, прийнято тензорні характеристики, означені щодо актуальної (деформованої) конфігурації — тензор напружень Коші та міри деформації Альманзі або Фінґера. У рамках запропонованої нелінійної теорії побудовано декілька варіантів системи рівнянь динаміки малих пружних збурень у неоднорідно деформованому твердому континуумі, лінеаризованої стосовно деформації збурення. Коефіцієнти отриманих рівнянь залежать від локальних параметрів початкового напружено-деформованого стану, заданих в актуальній конфігурації. У такому вигляді їх зручно застосовувати для опису хвильових процесів, які збуджують у неоднорідно деформованих тілах, щоб отримати апостеріорну інформацію про актуальний напружено-деформований стан цих об’єктів.A nonlinear theory of elasticity as applied to problems of tensor fields tomography in non-uniformly strained solids has been developed. As constitutive thermodynamic parameters of the theory, corresponding the process of deformation, the tensor characteristics determinate in the actual configuration — tensors Almansi’s and Finger’s have been used. In the frame of the theory several variants of system equations for dynamics of small elastic disturbances in non-uniformly strained continuum, linearized with respect to the amplitude of the disturbance, have been built. These equations coefficients are depended on local parameters of the body stress-strained state, determined in local base of the actual configuration. In such a form they are convenient to use for describing of the wave processes in non-uniformly strained solids activated to obtain some a posteriori information about the actual stress-strained state of such objects.Развита нелинейная теория упругости применительно к задачам томографии тензорных полей в неоднородно деформированных твердых телах. В качестве определяющих параметров локального термодинамического состояния, соответствующих процессу деформирования, приняты тензорные характеристики, определяемые относительно актуальной (деформированной) конфигурации — тензор напряжений Коши и меры деформации Альманзи или Фингера. В рамках предложенной нелинейной теории построено несколько вариантов системы уравнений динамики малых упругих возмущений в неоднородно деформированном твердом континууме, линеаризированной относительно деформации возмущения. Коэффициенты полученных уравнений зависят от локальных параметров напряженно-деформированного состояния, заданных в актуальной конфигурации. В таком виде их удобно применять для описания волновых процессов, которые возбуждают в неоднородно деформированных телах для получения апостериорной информации об актуальном напряженно-деформированном состоянии этих объектов

Effect of exercise after a deep venous thrombosis:A systematic review

Post-thrombotic syndrome (PTS) is a common complication after deep vein thrombosis (DVT) and has a major impact on physical symptoms, quality of life (QoL) and economic costs. Relatively simple lifestyle interventions as physical exercise might reduce PTS severity and increase QoL. To evaluate the direct and long-term effects of physical activity in patients with an acute or previous DVT. We conducted a systematic review through an additional search from 2007 up to March 2022, to complement the comprehensive systematic review of Kahn et al. Articles evaluating the effect of exercise after a DVT including symptoms, QoL and the incidence and severity of PTS, were included. Quality of the studies was assessed using a GRADE-like checklist and results were reported according to the PRISMA Statement. Ten studies were included, seven randomized controlled trials and three cohort studies. We identified three types of physical activity based on timing and duration; (1) early mobilisation in the acute phase of the DVT; (2) short duration exercise 1 year after DVT and (3) prolonged exercise during follow-up after a previous DVT. Early mobilisation showed improvement in QoL and pain reduction and after 2 years it resulted in a significant reduction of PTS severity. Prolonged supervised exercise resulted in improvement of QoL. In addition, positive effects on symptoms of venous insufficiency and muscle functions were observed. None of the included studies reported an increased risk of PTS or worsening of symptoms due to physical activity. Physical exercise after a DVT is safe, improves QoL, reduces pain and decreases PTS severity. Lifestyle intervention such as guided individualized training programs can be a useful supplementary therapy for patients after a DVT or for PTS patients. Optimal training programs may be identified by further studies that improve patient-oriented outcomes for both adults and children after a DVT.</p