1. Attitudes of secondary school students towards teaching styles before and during the COVID-19 pandemicMarijana Škutor, 2023, original scientific article Abstract: The aim of this paper was to examine students’ attitudes towards teaching styles before and during the COVID-19 pandemic. Mean values were calculated using descriptive statistics, and the T-test for independent samples was used to determine the existence of statistically significant differences between groups. After testing the difference in student assessment of the teachers’ style in two different school years, no statistically significant difference was found, potentially owing to student adaptation to the situation. A positive- sign correlation coefficient between the democratic and laissez-faire styles was recorded at a significance level of p<0.05.
Keywords: teaching quality, teaching skills, professional student-teacher relationship, social distance, stress
Published in DKUM: 28.07.2025; Views: 0; Downloads: 2
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2. Evaluating middle-distance passenger transportation : a comparison of the time efficiency, sustainability, and break-even distances between high-speed-rail and air travel in SwedenMartin Fale, Tomaž Kramberger, Bojan Rupnik, Shen Lixin, Tea Vizinger, 2025, original scientific article Abstract: Debate regarding the use of airplanes or high-speed trains in middle-distance passenger transportation has evolved into a strong field of research. With the aim to mitigate the environmental footprint of air travel, the European Union’s initiatives are focused on redirecting passengers from airplanes to high-speed trains. This shift is hampered by significant variations in train accessibility across Europe. Using Sweden as an example, we tested the break-even distance and evaluated the findings from both a time-efficiency perspective and a sustainability perspective. Airplanes hold the upper hand on high-speed trains in middle-distance passenger transportation from the time perspective. This perspective provides us with a clear answer, but if we consider the sustainability perspective, it may affect the results. The results indicate that the presented proof of concept makes sense and can be easily adapted to any decision-making process regarding the choice of the preferable transportation mode, although the procedure is extremely time consuming. For policymakers, this proof of concept can represent a priceless tool because the resulting figures carry valuable information about (under)developed and (less-)integrated transportation modes in commuting and transportation systems.
Keywords: time efficiency, sustainability, breakeven distance, high-speed-rail (HSR) travel, air travel
Published in DKUM: 01.07.2025; Views: 0; Downloads: 2
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3. Power-based concept for current injection by inverter-interfaced distributed generations during transmission-network faultsBoštjan Polajžer, Bojan Grčar, Jernej Černelič, Jožef Ritonja, 2021, original scientific article Abstract: This paper analyzes the influence of inverter-interfaced distributed generations’ (IIDGs)
response during transmission network faults. The simplest and safest solution is to switch IIDGs
off during network faults without impacting the network voltages. A more elaborate and efficient
concept, required by national grid codes, is based on controlling the IIDGs’ currents, involving
positive- and negative-sequence voltage measured at the connection point. In this way the magnitude
and phase of the injected currents can be adjusted, although the generated power will depend on the
actual line voltages at the connection point. Therefore, an improved concept is proposed to adjust
IIDGs’ fault current injection through the required active and reactive power, employing the same
voltage characteristics. The proposed, i.e., power-based concept, is more definite than the currentbased one, since the required power will always be generated. The discussed concepts for the fault
current injection by IIDGs were tested in different 110-kV networks with loop and radial topologies,
and for different short-circuit capabilities of the aggregated network supply. Based on extensive
numerical calculations, the power-based concept during transmission networks faults generates
more reactive power compared to the current-based concept. However, the voltage support by IIDGs
during transmission networks faults, regardless of the concept being used, is influenced mainly
by the short-circuit capability of the aggregated network supply. As regards distance protection
operation, it is influenced additionally by the network topology, i.e., in radial network topology, the
remote relay’s operation can be delayed due to a largely seen impedance.
Keywords: distributed generation, fault current injection, voltage support, distance protection, transmission network faults
Published in DKUM: 16.06.2025; Views: 0; Downloads: 8
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4. Creating vector profile graph in ArcGIS Pro based on hiking trail tracking with AllTrails appKlemen Prah, 2024, original scientific article Abstract: This paper proposes a model for creating a vector profile graph in ArcGIS Pro based on AllTrails tracking. The vector profile graph is important for route’s geometric measurements and spatial analysis in GIS. The model was created in an Excel table, based on the AllTrails output Excel data, and implemented in ArcGIS Pro. A model needed to be equipped with several attributes, including the coordinates of the initial and all other points of the vector profile graph. The same Excel model was also used to create a vector profile graph based on the output of the Stack Profile tool. The two vector profile graphs were compared with each other. Comparison showed significant differences in elevation and surface distance between them. In general, the profile graph created using the Stack Profile tool shows lower elevations and shorter surface distance. This study also points out the issues of positional error that can occur when tracking routes with smartphones, and the discrepancies in creating vector profile graphs using different approaches.
Keywords: vector profile graph, hiking route, distance, elevation, AllTrails
Published in DKUM: 26.03.2025; Views: 0; Downloads: 7
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5. The Graovac-Pisanski index of connected bipartite graphs with applications to hydrocarbon moleculesMatevž Črepnjak, Martin Knor, Niko Tratnik, Petra Žigert Pleteršek, 2021, original scientific article Abstract: The Graovac-Pisanski index, also called the modified Wiener index, was introduced in 1991 and represents an extension of the original Wiener index, because it considers beside the distances in a graph also its symmetries. Similarly as Wiener in 1947 showed the correlation of the Wiener indices of the alkane series with the boiling points, in 2018 the connection between the GraovacPisanski index and the melting points of some hydrocarbon molecules was established. In this paper, we prove that the Graovac-Pisanski index of any connected bipartite graph as well as of any connected graph on an even number of vertices is an integer number. These results are applied to some important families of hydrocarbon molecules. By using a computer programme, the graphs with a non-integer Graovac-Pisanski index on at most nine vertices are counted. Finally, an infinite class of unicyclic graphs with a non-integer Graovac-Pisanski index is described.
Keywords: modified Wiener index, Graovac-Pisanski index, graph distance, automorphism group, hydrocarbons, carbon nanostructures
Published in DKUM: 14.02.2025; Views: 0; Downloads: 8
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6. A case study on entropy-aware block-based linear transforms for lossless image compressionBorut Žalik, David Podgorelec, Ivana Kolingerová, Damjan Strnad, Štefan Kohek, 2024, original scientific article Abstract: Data compression algorithms tend to reduce information entropy, which is crucial, especially in the case of images, as they are data intensive. In this regard, lossless image data compression is especially challenging. Many popular lossless compression methods incorporate predictions and various types of pixel transformations, in order to reduce the information entropy of an image. In this paper, a block optimisation programming framework is introduced to support various experiments on raster images, divided into blocks of pixels. Eleven methods were implemented within , including prediction methods, string transformation methods, and inverse distance weighting, as a representative of interpolation methods. Thirty-two different greyscale raster images with varying resolutions and contents were used in the experiments. It was shown that reduces information entropy better than the popular JPEG LS and CALIC predictors. The additional information associated with each block in is then evaluated. It was confirmed that, despite this additional cost, the estimated size in bytes is smaller in comparison to the sizes achieved by the JPEG LS and CALIC predictors.
Keywords: computer science, information entropy, prediction, inverse distance transform, string transformations
Published in DKUM: 07.01.2025; Views: 0; Downloads: 10
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7. Region segmentation of images based on a raster-scan paradigmLuka Lukač, Andrej Nerat, Damjan Strnad, Štefan Horvat, Borut Žalik, 2024, original scientific article Abstract: This paper introduces a new method for the region segmentation of images. The approach is based on the raster-scan paradigm and builds the segments incrementally. The pixels are processed in the raster-scan order, while the construction of the segments is based on a distance metric in regard to the already segmented pixels in the neighbourhood. The segmentation procedure operates in linear time according to the total number of pixels. The proposed method, named the RSM (raster-scan segmentation method), was tested on selected images from the popular benchmark datasets MS COCO and DIV2K. The experimental results indicate that our method successfully extracts regions with similar pixel values. Furthermore, a comparison with two of the well-known segmentation methods—Watershed and DBSCAN—demonstrates that the proposed approach is superior in regard to efficiency while yielding visually similar results.
Keywords: segment, image analysis, distance metric, Watershed, DBSCAN
Published in DKUM: 05.12.2024; Views: 0; Downloads: 6
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8. COVID-19 and social distancing : ǂa ǂcross-cultural study of interpersonal distance preferences and touch behaviors before and during the pandemicIlona Croy, Andreja Avsec, Tina Kavčič, Bojan Musil, Nejc Plohl, Gaja Zager Kocjan, Maja Zupančič, 2024, original scientific article Abstract: The COVID-19 pandemic has led to the introduction of unprecedented safety measures, one of them being physical distancing recommendations. Here, we assessed whether the pandemic has led to long-term effects on two important physical distancing aspects, namely interpersonal distance preferences and interpersonal touch behaviors. We analyzed nearly 14,000 individual cases from two large, cross-cultural surveys – the first conducted 2 years prior to the pandemic and the second during a relatively stable period of a decreased infection rate in May-June 2021. Preferred interpersonal distances increased by 54% globally during the COVID-19 pandemic. This increase was observable across all types of relationships, all countries, and was more pronounced in individuals with higher self-reported vulnerability to diseases. Unexpectedly, participants reported a higher incidence of interpersonal touch behaviors during than before the pandemic. We discuss our results in the context of prosocial and self-protection motivations that potentially promote different social behaviors.
Keywords: neverbalna komunikacija, preference glede medosebne razdalje, medosebni dotiki, pandemija, kovid, COVID-19, fizična distanca, medkulturna psihologija, coronavirus, nonverbal communication, interpersonal distance preferences, interpersonal touch behaviour, cross-cultural psychology, physical distancing
Published in DKUM: 02.08.2024; Views: 89; Downloads: 12
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9. Span of a graph : keeping the safety distanceIztok Banič, Andrej Taranenko, 2023, original scientific article Abstract: Inspired by Lelek's idea from [Disjoint mappings and the span of spaces, Fund. Math. 55 (1964), 199 -- 214], we introduce the novel notion of the span of graphs. Using this, we solve the problem of determining the \emph{maximal safety distance} two players can keep at all times while traversing a graph. Moreover, their moves must be made with respect to certain move rules. For this purpose, we introduce different variants of a span of a given connected graph. All the variants model the maximum safety distance kept by two players in a graph traversal, where the players may only move with accordance to a specific set of rules, and their goal: visit either all vertices, or all edges. For each variant, we show that the solution can be obtained by considering only connected subgraphs of a graph product and the projections to the factors. We characterise graphs in which it is impossible to keep a positive safety distance at all moments in time. Finally, we present a polynomial time algorithm that determines the chosen span variant of a given graph.
Keywords: strong span of a graph, direct span of a graph, Cartesian span of a graph, safety distance
Published in DKUM: 07.06.2024; Views: 98; Downloads: 13
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10. Changes in online distance learning behaviour of university students during the coronavirus disease 2019 outbreak, and development of the model of forced distance online learning preferencesMateja Ploj Virtič, Kosta Dolenc, Andrej Šorgo, 2021, original scientific article Abstract: Because of the Coronavirus Disease 2019 (COVID-19) outbreak, most universities were forced to choose Online Distance Learning (ODL). The study aimed to examine the response of university students to the new situation. A questionnaire was sent to the entire university student population. Based on responses from 606 students, it was revealed that use of all applications in ODL increased. However, only the use of MS Teams increased significantly, while the use of the other applications (email, Moodle, e-textbooks) increased in a range of low to medium in terms of effect sizes, and even nonsignificant for applications such as Padlet and Kahoot. Based on the replies of 414 respondents, a Model of Forced Distance Online Learning Preferences (MoFDOLP) based on Structural Equation Modeling was developed. With a chosen combination of predictors, we succeeded in predicting 95% of variance for Satisfaction, more than 50% for Continuance Preferences variance in MS Teams applications, and nearly 20% in the case of e-materials. Among hypothesized constructs, only Attitudes are a strong predictor of Satisfaction, while Organizational Support, Perceived Ease of Use and Learner Attitude toward Online Learning are not. Satisfaction is a good predictor of Continuance Preferences to use Information Technology after the lockdown ended.
Keywords: higher education, online distance learning, continuance preferences, COVID-19
Published in DKUM: 30.05.2024; Views: 111; Downloads: 24
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