Miracle-dz/UniFAR-FTUs huggingface dataset:
Automatic classification of Aurora-related tweets using machine learning methods

The constant flow of information by social media provides valuable information about all sorts of events at a high temporal and spatial resolution. Over the past few years we have been analyzing in real-time geological hazards/phenomena, such as earthquakes, volcanic eruptions, landslides, floods or the aurora, as part of the GeoSocial project, by geo-locating tweets filtered by keywords in a web-map. However, up to this date only a keyword-based filtering was applied that does not always filter out tweets that are unrelated to hazard-events. Therefore, this work explores five learning-based classification techniques: a Linear SVM and four Deep Neural Networks (DNNs): a Convolutional Neural Network (CNN), a Recurrent Neural Network (RNN), a RNN-Long-short-term memory (RNN-LSTM) and a RNN-Gated Recurrent Unit (GRU) for automatic hazard-event classification based on tweets about Aurora sightings. In addition, for the DNNS we also trained the algorithms using pre-trained word2vec word-embeddings. We finally evaluate the algorithms using two datasets, one from the Aurorasaurus application and one manually labeled in the BGS. We show that DNNs and especially the CNN perform better for both datasets and that there is potential for improvement. Our code is also available online.
Slippage Detection for Grasping Force Control of Robotic Hand Using Force Sensing Resistors

This paper presents the formulation of a nonlinear adaptive backstepping force control in grasping weight-varying objects using robotic hand driven by Pneumatic Artificial Muscle (PAM). The modelling and control problems arise from the high nonlinear PAM dynamics and the inherent hysteresis leading to a lack of robustness in the hand's performance. The robotic finger and the PAM actuator been mathematically modelled as a nonlinear second order system based on an empirical approach. An adaptive backstepping controller has been designed for force control of the pneumatic hand. The estimator of the system uncertainty is incorporated into the proposed control law and a slip detection strategy is introduced to grasp objects with changing weights. The simulation and experimental results show that the robotic hand can maintain grasping an object and stop further slippage when its weight is increased up to 500 g by detecting the slip signal from the force sensor. The results also have proven that the adaptive backstepping controller is capable to compensate the uncertain coulomb friction force of PAM actuator with maximum hysteresis error 0.18°.
SGD on Neural Networks Learns Functions of Increasing Complexity

We perform an experimental study of the dynamics of Stochastic Gradient Descent (SGD) in learning deep neural networks for several real and synthetic classification tasks. We show that in the initial epochs, almost all of the performance improvement of the classifier obtained by SGD can be explained by a linear classifier. More generally, we give evidence for the hypothesis that, as iterations progress, SGD learns functions of increasing complexity. This hypothesis can be helpful in explaining why SGD-learned classifiers tend to generalize well even in the over-parameterized regime. We also show that the linear classifier learned in the initial stages is "retained" throughout the execution even if training is continued to the point of zero training error, and complement this with a theoretical result in a simplified model. Key to our work is a new measure of how well one classifier explains the performance of another, based on conditional mutual information.
Effects of mobile phone electromagnetic fields at nonthermal SAR values on melatonin and body weight of Djungarian hamsters (Phodopus sungorus)

Abstract: In three experiments, adult male Djungarian hamsters (Phodopus sungorus) were exposed 24 hr/day for 60 days to radio frequency electromagnetic fields (RF‐EMF) at 383, 900, and 1800 MHz, modulated according to the TETRA (383 MHz) and GSM standards (900 and 1800 MHz), respectively. A radial waveguide system ensured a well defined and uniform exposure at whole‐body averaged specific absorption rates of 80 mW/kg, which is equal to the upper limit of whole‐body exposure of the general population in Germany and other countries. For each experiment, using two identical waveguides, hamsters were exposed (n = 120) and sham‐exposed (n = 120) in a blind fashion. In all experiments, pineal and serum melatonin levels as well as the weights of testes, brain, kidneys, and liver were not affected. At 383 MHz, exposure resulted in a significant transient increase in body weight up to 4%, while at 900 MHz this body weight increase was more pronounced (up to 6%) and not transient. At 1800 MHz, no effect on body weight was seen. The results corroborate earlier findings which have shown no effects of RF‐EMF on melatonin levels in vivo and in vitro. The data are in accordance with the hypothesis that absorbed RF energy may result in metabolic changes which eventually cause body weight increases in exposed animals. The data support the notion that metabolic effects of RF‐EMFs need to be investigated in more detail in future studies.
Estimating and inferring the maximum degree of stimulus‐locked time‐varying brain connectivity networks

Neuroscientists have enjoyed much success in understanding brain functions by constructing brain connectivity networks using data collected under highly controlled experimental settings. However, these experimental settings bear little resemblance to our real‐life experience in day‐to‐day interactions with the surroundings. To address this issue, neuroscientists have been measuring brain activity under natural viewing experiments in which the subjects are given continuous stimuli, such as watching a movie or listening to a story. The main challenge with this approach is that the measured signal consists of both the stimulus‐induced signal, as well as intrinsic‐neural and nonneuronal signals. By exploiting the experimental design, we propose to estimate stimulus‐locked brain networks by treating nonstimulus‐induced signals as nuisance parameters. In many neuroscience applications, it is often important to identify brain regions that are connected to many other brain regions during cognitive process. We propose an inferential method to test whether the maximum degree of the estimated network is larger than a prespecific number. We prove that the type I error can be controlled and that the power increases to one asymptotically. Simulation studies are conducted to assess the performance of our method. Finally, we analyze a functional magnetic resonance imaging dataset obtained under the Sherlock Holmes movie stimuli.
Dynamics on Shift Spaces with a Hole.

We consider the problem of comparing escape rates of the shift map on a subshift of finite type into the holes which are a union of equal number of cylinders based at words of identical length. The escape rate calculation leads to a combinatorial problem, in particular, we will see that the escape rate relates to the asymptotic behavior of the number of strings of fixed length that do not contain a fixed set of (forbidden) strings of identical length as substrings. We will also explore the relationship between the minimal period of the hole and the escape rate. This paper generalizes results of Bunimovich and Yurchenko [5] in which there was only one forbidden string.
Mapping the Galactic disc with the LAMOST and Gaia red clump sample: II. 3D asymmetrical kinematics of mono-age populations in the disc between 6–14  kpc

We perform analysis of the 3D kinematics of Milky Way disc stars in mono-age populations. We focus on stars between Galactocentric distances of R = 6 and 14 kpc, selected from the combined LAMOST Data Release 4 (DR4) red clump giant stars and Gaia DR2 proper motion catalogue. We confirm the 3D asymmetrical motions of recent works and provide time tagging of the Galactic outer disc asymmetrical motions near the anticentre direction out to Galactocentric distances of 14 kpc. Radial Galactocentric motions reach values up to 10 km s−1, depending on the age of the population, and present a north–south asymmetry in the region corresponding to density and velocity substructures that were sensitive to the perturbations in the early 6 Gyr. After that time, the disc stars in this asymmetrical structure have become kinematically hotter, and are thus not sensitive to perturbations, and we find the structure is a relatively younger population. With quantitative analysis, we find stars both above and below the plane at R ≳ 9 kpc that exhibit bending mode motions of which the sensitive duration is around 8 Gyr. We speculate that the in-plane asymmetries might not be mainly caused by a fast rotating bar, intrinsically elliptical outer disc, secular expansion of the disc, or streams. Spiral arm dynamics, out-of-equilibrium models, minor mergers or others are important contributors. Vertical motions might be dominated by bending and breathing modes induced by complicated inner or external perturbers. It is likely that many of these mechanisms are coupled together.
Effects of baryons on weak lensing peak statistics

Upcoming weak-lensing surveys have the potential to become leading cosmological probes provided all systematic effects are under control. Recently, the ejection of gas due to feedback energy from active galactic nuclei (AGN) has been identified as major source of uncertainty, challenging the success of future weak-lensing probes in terms of cosmology. In this paper we investigate the effects of baryons on the number of weak-lensing peaks in the convergence field. Our analysis is based on full-sky convergence maps constructed via light-cones from N-body simulations, and we rely on the baryonic correction model of [1] to model the baryonic effects on the density field. As a result we find that the baryonic effects strongly depend on the Gaussian smoothing applied to the convergence map. For a DES-like survey setup, a smoothing of θk≳8 arcmin is sufficient to keep the baryon signal below the expected statistical error. Smaller smoothing scales lead to a significant suppression of high peaks with 𝒮/𝒩> 2, while lower peaks are not affected. The situation is more severe for a Euclid-like setup, where a smoothing of θk≳16 arcmin is required to keep the baryonic suppression signal below the statistical error. Smaller smoothing scales require a full modelling of baryonic effects since both low and high peaks are strongly affected by baryonic feedback.
Probing Blazar Emission Processes with Optical/Gamma-Ray Flare Correlations

Even with several thousand Fermi-Large Area Telescope (LAT) blazar detections, the γ-ray emission mechanism is poorly understood. We explore correlated optical/γ-ray flux variations for 178 Fermi-LAT blazars regularly monitored by the Katzman Automatic Imaging Telescope, the Small and Moderate Aperture Research Telescope System, and the Steward Observatory. Out of the 178 sources, 121 show a measurable (>1σ) discrete correlation function peak. Using the derived time lags and Bayesian block light-curve decompositions, we measure the fraction of common and orphan flares between the two bands. After accounting for sampling and sensitivity limitations we quantify for the first time the true orphan flare rates of optical and γ-ray flares: 54.5% of optical and 20% of γ-ray flares are orphan events. Both the intraband temporal relation and the small orphan γ-ray flare fraction point toward leptonic processes as the likely mechanisms for the high-energy emission. Motivated to discriminate between synchrotron self-Compton (SSC) and external-Compton dominance in individual sources, we use the flux–flux variations to determine the slope m of the log fopt–log fγ dependence. The slope distribution suggests a bimodal population with high and intermediate synchrotron peak objects showing larger m than low synchrotron peak objects. We find that m is naturally decreased through pollution from the orphan (typically optical) flares and develop a method to statistically recover, given the sources’ measured orphan flare rate, the intrinsic m. While source classes show composite behavior, the majority of BL Lac objects favor m = 2, indicating an SSC origin for the γ-rays. No preference for either m is found in flat spectrum radio quasars.
Uncertainty-based Continual Learning with Adaptive Regularization

We introduce a new neural network-based continual learning algorithm, dubbed as Uncertainty-regularized Continual Learning (UCL), which builds on traditional Bayesian online learning framework with variational inference. We focus on two significant drawbacks of the recently proposed regularization-based methods: a) considerable additional memory cost for determining the per-weight regularization strengths and b) the absence of gracefully forgetting scheme, which can prevent performance degradation in learning new tasks. In this paper, we show UCL can solve these two problems by introducing a fresh interpretation on the Kullback-Leibler (KL) divergence term of the variational lower bound for Gaussian mean-field approximation. Based on the interpretation, we propose the notion of node-wise uncertainty, which drastically reduces the number of additional parameters for implementing per-weight regularization. Moreover, we devise two additional regularization terms that enforce stability by freezing important parameters for past tasks and allow plasticity by controlling the actively learning parameters for a new task. Through extensive experiments, we show UCL convincingly outperforms most of recent state-of-the-art baselines not only on popular supervised learning benchmarks, but also on challenging lifelong reinforcement learning tasks. The source code of our algorithm is available at this https URL.
How FOSS Replaced Proprietary Software at a University: An Improvisation Perspective in a Low-income Country

The purpose of this study is to understand the rationale for and the process of replacing an imported proprietary higher education management software with a locally developed free and open source software (FOSS). Information Systems (IS) research on FOSS and higher education in low-income countries has focused more on teaching and learning. Less attention has thus been paid to the area of management and administration. Also, low-income country IS research on technology transfer has focused more on applications from the high-income world. Less research therefore exists on transfers between low-income countries. To address these research gaps, this study employs improvisation theory and interpretive case study methodology to investigate why and how a low-income country university replaced a proprietary higher education management software from another low-income country with a locally developed FOSS. The findings show that the university did so through improvisation to overcome the rigidity of the proprietary software and benefit from the flexibility of the FOSS. The study offers rich insight into how low-income country universities can deploy FOSS through improvisation to address design-actuality gap with imported proprietary software and also presents implications for research and practice.
Hue combinations for the web: Towards a repertoire of design guidelines for combining color hues based on cultural background

Existing research shows that users tend to assess the visual appeal of a web page within 50 ms and color is the first thing that is noticed on a screen. This directly influences the user's perception of a website, and a choice of appealing color combinations may, therefore, be crucial in successful web design. This article aims to identify, formulate, and evaluate design guidelines to support designers in the process of combining color hues for websites in the context of the Swedish and Thai cultures. A quantitative approach was used to evaluate the proposed design guidelines. The results show that culture plays a role in the evaluation of color hue combinations; Thai participants rated Thai designs significantly more highly than the Swedish participants, but the reverse was not true, and Thai designs were rated more highly than Swedish designs by all participants. The results may have implications for practitioners working in the field of web design and for the broader debate of cultural influence on color preference.
The bias of the sample mean in multi-armed bandits can be positive or negative

It is well known that in stochastic multi-armed bandits (MAB), the sample mean of an arm is typically not an unbiased estimator of its true mean. In this paper, we decouple three different sources of this selection bias: adaptive \emph{sampling} of arms, adaptive \emph{stopping} of the experiment and adaptively \emph{choosing} which arm to study. Through a new notion called ``optimism'' that captures certain natural monotonic behaviors of algorithms, we provide a clean and unified analysis of how optimistic rules affect the sign of the bias. The main takeaway message is that optimistic sampling induces a negative bias, but optimistic stopping and optimistic choosing both induce a positive bias. These results are derived in a general stochastic MAB setup that is entirely agnostic to the final aim of the experiment (regret minimization or best-arm identification or anything else). We provide examples of optimistic rules of each type, demonstrate that simulations confirm our theoretical predictions, and pose some natural but hard open problems.
Online Measurement-Based Estimation of Dynamic System State Matrix in Ambient Conditions

In this paper, a purely measurement-based method is proposed to estimate the dynamic system state matrix by applying the regression theorem of the multivariate Ornstein-Uhlenbeck process. The proposed method employs a recursive algorithm to minimize the required computational effort, making it applicable to the real-time environment. One main advantage of the proposed method is model independence, i.e., it is independent of the network model and the dynamic model of generators. Among various applications of the estimated matrix, detecting and locating unexpected network topology change is illustrated in details. Simulation studies have shown that the proposed measurement-based method can provide an accurate and efficient estimation of the dynamic system state matrix under the occurrence of unexpected topology change. Besides, various implementation conditions are tested to show that the proposed method can provide accurate approximation despite measurement noise, missing phasor measurement units (PMUs), and the implementation of higher-order generator models with control devices.
The nonlinear Schrödinger equation with white noise dispersion on quantum graphs

We show that the nonlinear Schr\"{o}dinger equation (NLSE) with white noise dispersion on quantum graphs is globally well-posed in $L^2$ once the free deterministic Schr\"{o}dinger group satisfies a natural $L^1-L^{\infty}$ decay, which is verified in many examples. Also, we investigate the well-posedness in the energy domain in general and in concrete situations, as well as the fact that the solution with white noise dispersion is the scaling limit of the solution to the NLSE with random dispersion.
Discovery of new stellar groups in the Orion complex

We test the ability of two unsupervised machine learning algorithms,EnLinkand Shared Nearest Neighbor (SNN), to identify stellar groupings in the Orion star-forming complex as an application to the 5D astrometric data fromGaiaDR2. The algorithms represent two distinct approaches to limiting user bias when selecting parameter values and evaluating the relative weights among astrometric parameters.EnLinkadopts a locally adaptive distance metric and eliminates the need for parameter tuning through automation. The original SNN relies only on human input for parameter tuning so we modified SNN to run in two stages. We first ran the original SNN 7000 times, each with a randomly generated sample according to within-source co-variance matrices provided inGaiaDR2 and random parameter values within reasonable ranges. During the second stage, we modified SNN to identify the most repeating stellar groups from the 25 798 we obtained in the first stage. We recovered 22 spatially and kinematically coherent groups in the Orion complex, 12 of which were previously unknown. The groups show a wide distribution of distances extending as far as about 150 pc in front of the star-forming Orion molecular clouds, to about 50 pc beyond them, where we, unexpectedly, find several groups. Our results reveal the wealth of sub-structure in the OB association, within and beyond the classical Blaauw Orion OBI sub-groups. A full characterization of the new groups is essential as it offers the potential to unveil how star formation proceeds globally in large complexes such as Orion.
How does Gauge Cooling Stabilize Complex Langevin?

We study the mechanism of the gauge cooling technique to stabilize the complex Langevin method in the one-dimensional periodic setting. In this case, we find the exact solutions for the gauge transform which minimizes the Frobenius norm of link variables. Thereby, we derive the underlying stochastic differential equations by continuing the numerical method with gauge cooling, and thus provide a number of insights on the effects of gauge cooling. A specific case study is carried out for the Polyakov loop model in $SU(2)$ theory, in which we show that the gauge cooling may help form a localized distribution to guarantee there is no excursion too far away from the real axis.
Pro‐arrhythmogenic effects of the S140G KCNQ1 mutation in human atrial fibrillation – insights from modelling

• A previous study has identified a gene mutation (KCNQ1 S140G) in some patients with a familial form of atrial fibrillation, one of the most common cardiac rhythm disturbances causing morbidity and mortality. A causal link between the mutation and genesis of atrial fibrillation has not yet been directly demonstrated. • Increased IKs arising from the KCNQ1 S140G mutation abbreviated atrial action potential duration (APD) and effective refractory period (ERP) and flattened APD and ERP restitution curves. It reduced atrial conduction velocity at low excitation rates, but increased it at high excitation rates that facilitated the conduction of high rate atrial excitation waves. • The mutation increased tissue susceptibility for initiation and maintenance of atrial arrhythmias. • The mutation stabilizes and accelerates re‐entrant excitation waves, leading to rapid and sustained re‐entry. • This study provides novel insights towards understanding the mechanisms underlying the pro‐arrhythmic effects of the KCNQ1 S140G mutation.
Cutaneous and ocular signs of childhood rosacea.

UNLABELLED Objectives To describe the clinical features of cutaneous and ocular manifestations of childhood rosacea, to propose diagnostic criteria, and to emphasize the possible severity of ocular complications in this age group. DESIGN Retrospective study. SETTING Tertiary referral center. Patients Children aged 1 to 15 years who had received a diagnosis of cutaneous and/or ocular rosacea and were seen between January 1, 1996, and December 31, 2005. RESULTS Of 20 patients, 11 had ocular and cutaneous rosacea, 6 had isolated cutaneous involvement, and 3 had isolated ocular involvement. Dermatologic examination results were sufficient to diagnose rosacea in 12 of the patients (60%). The most common presentation was a papulopustular eruption on a telangiectatic background. In 11 patients (55%), ocular involvement preceded the skin eruption. Among the ophthalmologic manifestations, chalazions and blepharoconjunctivitis were the main presenting symptoms; keratitis was observed in 4 patients and corneal ulcers in 2. Ten patients were treated with oral metronidazole. Intermittent treatment for at least 3 months was used to avoid neurologic toxic effects and to achieve complete remission. Conclusion Although rare, childhood rosacea should be recognized because of the possible severity of ocular involvement.