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A partial solar eclipse occurred on 25 October 2022, in the central and northern parts of Europe. The partial solar eclipse was observed at Aalto University Metsähovi Radio Observatory, Finland at the radio wavelength of 8 mm (37 GHz). In Finland, the magnitude of the partial solar eclipse was 62.7 %. Solar radio maps at the time cadence of about 9 minutes were observed over the whole eclipse. The solar eclipse observations could be used for instrument calibration purposes. This paper investigates the solar brightness temperature, the limb brightening effect, the height of the chromosphere and the location of radio brightening using the aforementioned partial solar eclipse observations. We got the confirmation that our earlier results are consistent, e.g., the solar brightness temperature matches with 8100 K ± 300 K. It was also possible to detect limb brightening effect. However, the prevailing solar activity might have distorted the final conclusions. The Moon should operate as a focusing element and the location of radio brightenings could be defined more carefully than in the normal conditions. We investigated this feature. Our results are in some parts unexpected and need further investigations. [ABSTRACT FROM AUTHOR]

Keystroke authentication is a well-established biometric technique that has gained significant attention due to its non-intrusive and continuous characteristics. The method analyzes the unique typing patterns of individuals to verify their identity while interacting with the keyboard, both virtual and hardware. Current deep-learning approaches like TypeNet and TypeFormer focus on generating biometric signatures as embeddings for the entire typing sequence. The authentication process is defined using the Euclidean distances between the new typing embedding and the saved biometric signatures. This paper introduces a novel approach called DoubleStrokeNet for authenticating users through keystroke analysis using bigram embeddings. Unlike conventional methods, our model targets the temporal features of bigrams to generate user embeddings. This is achieved using a Transformer-based neural network that distinguishes between different bigrams. Furthermore, we employ self-supervised learning techniques to compute embeddings for both bigrams and users. By harnessing the power of the Transformer's attention mechanism, the DoubleStrokeNet approach represents a significant departure from existing methods. It allows for a more precise and accurate assessment of user authenticity, specifically emphasizing the temporal characteristics and latent representations of bigrams in deriving user embeddings. Our experiments were conducted using the Aalto University keystrokes datasets, which include 136 million keystrokes from 168,000 subjects using physical keyboards and 63 million keystrokes acquired on mobile devices from 60,000 subjects. The DoubleStrokeNet outperforms the TypeNet-based authentication system using 10 enrollment typing sequences, achieving Equal Error Rate (EER) values of 0.75% and 2.35% for physical and touchscreen keyboards, respectively. [ABSTRACT FROM AUTHOR]

To determine the bidirectional transmittance distribution function (BTDF) of diffusely transmitting materials, two new primary facilities have been developed at the Physikalisch-Technische Bundesanstalt (PTB) and Aalto University (Aalto). A detailed description of both facilities and the different approaches used are presented in this paper. The performance of both facilities is compared by determining the BTDF of two different diffuser types in both in-plane and out-of-plane bidirectional geometries at four different wavelengths in the visible spectral range. Due to delayed completion of PTB's primary facility, the measured BTDF values are compared between Aalto's primary facility and another PTB setup, whose measurement scales are successfully transferred to PTB's primary facility by an internal comparison. A thorough analysis of the measurement uncertainty is presented, leading to a combined k = 1 standard uncertainty of 0.8%–1.2% for PTB's primary facility and 1.3%–1.7% for Aalto's primary facility. The BTDF results obtained agree well within their expanded k = 2 uncertainty. This indirect bilateral comparison shows that Aalto's and PTB's new facilities are suited as primary reference setups for the determination of the BTDF. These studies also reveal action points to improved measurement capabilities and for a reduction of the measurement uncertainty, depending on the type of diffuser under test. [ABSTRACT FROM AUTHOR]

On 4 July 2022, a complex low-frequency solar radio burst was observed in Metsähovi Radio Observatory of Aalto University. The radio burst was observed at a frequency range between 20 and 80 MHz. In GOES (Geostationary Operational Environmental Satellite) class, the event was classified as C5.1. However, coronal mass ejection (CME) was not associated to this event. The observed radio burst was a long-lasting (~10 minutes) event, and it could be mainly classified as type II solar radio event. Also type III solar events were observed before long-lasting type II event. The event includes common frequency drifting emission structures, both fundamental and harmonic structures, but also rarely observed continuum-like or stationary structure. It is assumed that the continuum-like radio emission structure is originated from the stationary flare (coronal) loop, which was visible over the whole event. The drifting emission structure means accelerated electrons, which are produced by the shock related phenomena. The paper provides the observations from this event on radio wavelength, and also soft-X-ray regime and optical wavelength (AIA 171). In addition, a possible, simplified scenario is presented for forming the drifting and continuum solar radio emissions in type II solar burst. [ABSTRACT FROM AUTHOR]

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Photogrammetric techniques have been applied in archaeology for over 140 years, but recently, automation in software has significantly increased the popularity of photogrammetry. In 2018, the Master's Programme in Cultural Heritage at Helsinki University arranged a special intensive hands-on course on geodesy, photogrammetry and laser scanning in Greece in order to provide more in-depth practical skills to students in an inspiring environment. The course was established in co-operation with Aalto University and the Finnish Institute at Athens. In this article, we describe how practical photogrammetry can be learned on an intensive hands-on course. Hands-on experiences and experimental learning enable good practical skills and also a deeper connection and understanding of theory. We believe that the students on the course managed to add photogrammetry to their archaeological toolboxes for the rest of their careers. [ABSTRACT FROM AUTHOR]

Cracks in MPM (CRAMP) is one of the most prominent discrete crack simulation methods in the Material Point Method (MPM) due to its simplicity and versatility. However, CRAMP is yet to include the capability to simulate concurrent crack initiations and propagations, as well as propagation to the edge of the material domain. The method proposed in this paper enables the simulation of multiple crack paths with CRAMP via the dynamic assignment of particles to separate grids while minimizing the number of necessary grids. It also proposes methods of evaluating crack initiation and propagation via the Rankine criterion. The proposed methods are then implemented in an in-house Convected Particle Domain Interpolation (CPDI) MPM developed at Aalto University. To verify the integrity of the CPDI algorithm, our CPDI code with the proposed method implemented simulated a CPDI vortex. Furthermore, six fracture-simulation verification test cases were carried out: (1) through-crack in an infinite plate; (2) mode-I propagation; (3) initiation; (4) initiation with large deformations; (5) merging; (6) multiple initial cracks; and (7) radially-cracked thick ring. All these verification tests show successful initiation, propagation, merging, crack opening, and agreement with the results from the literature, as well as the convergence of various parameters with the expected rates. • Multiple crack initiation, propagation and merging in Material Point Method. • Efficient simulation of domain with multiple cracks in Material Point Method. • Rankine Criterion based crack propagation includes the release of fracture energy. • Fully dynamic simulations with cracks and advanced interpolation algorithms. • Cracks in Convected Particle Domain Interpolation Material Point Method. [ABSTRACT FROM AUTHOR]

Experiments on columnar freshwater ice indicated that there is no detected effect of the ice thickness on the fracture behavior of columnar freshwater S2 ice. The influence of thickness was studied using large laboratory-grown samples. Two series of Mode I fracture tests were carried out using deeply edge-cracked 3-by-6-metre rectangular plates loaded monotonically at 1...100 μ m/s. The ice was warm (above −0.5 °C), and the ice thickness varied in the range 10 – 40 cm. This paper analyzes the second series of tests and compares the results with the first series tests; the analysis of the latter was published in Gharamti et al. (2021) [2,3,4]. The viscoelastic fictitious crack model (VFCM) was applied to analyze the data and calculate the crack profile, fracture energy and the process zone size. The thickness affected only and linearly the values of the measured loads with no influence on the fracture properties: the apparent fracture toughness, fracture energy, crack opening displacements, notch sensitivity and process zone size. [Display omitted] • Large-scale experiments were conducted in the Ice and Wave tank of Aalto University (Finland). • Warm ice specimens (6 m × 3 m, > −0.5 C) were monotonically loaded to fracture. • The ice thickness varied in the range 10–40 cm. • The viscoelastic fictitious crack model (VFCM) was applied to analyze the data and calculate the crack profile, fracture energy and the process zone size. • There is no quantitative effect of the ice thickness on the fracture behavior of columnar freshwater S2 ice. [ABSTRACT FROM AUTHOR]

• Improved advanced elasto-plastic model for wood with multiple yield surfaces. • Improved stress integration algorithm and model implementation. • Large displacements finite strain CPDI simulations of compression and tension tests of spruce. Wood is a naturally occurring material widely used for construction. Due to its natural origin, wood properties vary and its behaviour is complex. This paper shows an implementation of a multi-surface elasto-plastic constitutive material model for wood into a custom explicit material point method code. The constitutive model chosen is one proposed by Schmidt & Kaliske with minor modifications to ensure better internal consistency. The model parameters are chosen based on literature data for spruce. The paper presents two Convected Particle Domain Interpolation Material Point Method simulations of experiments, both performed with the previously established model parameters. The first simulation replicates a compression test of a spruce specimen perpendicular to grain direction, carried out at the Department of Civil Engineering, Aalto University. The second simulation replicates an experiment from literature, in which a spruce specimen with knots is tensioned until failure. The numerical simulations successfully replicate the experimental outcomes qualitatively in terms of the deformation and load-displacement curves. Simulations of the three knotted specimens under tension, with introduced slight variation in wood grain direction, replicate different failure patterns with a similar failure load, resembling the behaviour of natural wooden structural elements. Additionally, one of the obtained failure patterns replicates that of the experiment well. [ABSTRACT FROM AUTHOR]

The aim of this work was to develop a technique to speed up complex joins in an incremental visual query system. When designing a visual, highly interactive interface for ad-hoc (read-only) queries, fast response times are of paramount importance. While a column-oriented DBMS reduces the inherent latency found in relational DBMS, there is still the question of how to index the data, especially so as to support complex joins. Equi-joins that involve a many-to-many relationship are an example of complex joins that arise frequently and whose efficient processing is essential for fast query processing. We present OVI-3, a NoSQL visual query system based on incremental querying that uses a simple directory-based indexing scheme for faster processing of such complex joins. The system has been piloted using real data from a student database at Aalto University. The results demonstrated that for certain complex joins the presented indexing scheme outperforms SQL queries from a data server, especially for queries involving anti-joins (negation), where OVI-3 provided an orders of magnitude speed improvement. [ABSTRACT FROM AUTHOR]

This practitioner research study examined the potential of arts education to support students' growth towards global citizenship including awareness, care, and understanding of--as well as active and responsible engagement in--current global challenges and social issues. We utilized research material generated during an interdisciplinary arts pedagogy course offered in subject teacher education at the University of the Arts Helsinki and Aalto University (Finland). During the course, students created teaching sessions in peer groups in which they explored pedagogical methods to enhance global citizenship through interdisciplinary arts education participation. In the study, we identified themes addressed in the teaching sessions: Renegotiating (cultural) identity, Facing otherness, Experiencing empathy, Coping with power and inequality, Awakening to ecological responsibility, and Engaging in critical and reflective thinking. Furthermore, we examined how arts education resonated with the aims of global education and discussed the many ways that arts education could support the cultivation of responsiveness and ethical awareness to advance transformative global citizenship. [ABSTRACT FROM AUTHOR]

A growing number of neuroscientific studies use films as experimental stimuli, making filmmakers partners in investigations of the brain. The author provides his perspective as a filmmaker who has been conducting neuroscience experiments in collaboration with a team of neuroscientists at the Brain and Mind Laboratory of Aalto University, Finland, over the last five years. This collaboration led to the development of a novel method of investigating the subconscious brain using films as well as insights on how to create more empathy-evoking films. Finally, the author discusses the relationship between social bias and boundaries of collaboration between filmmaking and neuroscience. [ABSTRACT FROM AUTHOR]

The article explores the collaboration between librarians and academics in information literacy settings at Aalto University in Finland. The study focuses on information sharing and social networks, using a qualitative case study approach to analyze the data collected through interviews, and finds that while collaboration exists for information literacy instruction, and the restructure of the library limits the effort devoted to instructional services, including information sharing.