1. High-performance deployment operational Data analytics of pre-trained multi-label classification architectures with differential-evolution-based hyperparameter optimization (AutoDEHypO)Teo Prica, Aleš Zamuda, 2025, original scientific article Abstract: This article presents a high-performance-computing differential-evolution-based hyperparameter optimization automated workflow (AutoDEHypO), which is deployed on a petascale supercomputer and utilizes multiple GPUs to execute a specialized fitness function for machine learning (ML). The workflow is designed for operational analytics of energy efficiency. In this differential evolution (DE) optimization use case, we analyze how energy efficiently the DE algorithm performs with different DE strategies and ML models. The workflow analysis considers key factors such as DE strategies and automated use case configurations, such as an ML model architecture and dataset, while monitoring both the achieved accuracy and the utilization of computing resources, such as the elapsed time and consumed energy. While the efficiency of a chosen DE strategy is assessed based on a multi-label supervised ML accuracy, operational data about the consumption of resources of individual completed jobs obtained from a Slurm database are reported. To demonstrate the impact on energy efficiency, using our analysis workflow, we visualize the obtained operational data and aggregate them with statistical tests that compare and group the energy efficiency of the DE strategies applied in the ML models.
Keywords: high-performance computing, operational data analytics, energy efficiency, machine learning, AutoML, differential avolution, optimization
Published in DKUM: 29.05.2025; Views: 0; Downloads: 2
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2. Behavioral expectations of business school students concerning extreme climate events : regional insights and implications for Southeast EuropeNikša Alfirević, Darko Rendulić, Sonja Mlaker Kač, 2025, original scientific article Abstract: Abstract: This article presents the role of environmental attitudes and self-efficacy in shaping the behavioral expectations of business students in Southeast Europe regarding extreme climate events. Conducted across twelve public and private business schools in five countries, the study provides a baseline for comparison with similar empirical research. Using multiple linear regression, we analyze the relationship between the proenvironmental attitudes and environmental self-efficacy to the students’ climate change expectations. Our results indicate that pro-environmental attitudes significantly predict the students’ expectations of extreme climate events, while environmental self-efficacy plays a secondary but statistically significant role. These findings extend the extant literature by focusing on the role of sustainability in business school curricula and the potential positive outcomes of experiential learning methods and approaches.
Keywords: pro-environmental attitudes, environmental self-efficiency, climate change expectations, business students, Southeast Europe
Published in DKUM: 27.03.2025; Views: 0; Downloads: 2
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3. Decontamination efficiency of thermal, photothermal, microwave, and steam treatments for biocontaminated household textilesBranko Neral, Selestina Gorgieva, Manja Kurečič, 2022, original scientific article Abstract: With the outbreak of the COVID-19 pandemic, textile laundering hygiene has proved to be
a fundamental measure in preventing the spread of infections. The first part of our study evaluated
the decontamination efficiency of various treatments (thermal, photothermal, and microwave) for
bio contaminated textiles. The effects on textile decontamination of adding saturated steam into
the drum of a household textile laundering machine were investigated and evaluated in the second
part of our study. The results show that the thermal treatment, conducted in a convection heating
chamber, provided a slight reduction in efficiency and did not ensure the complete inactivation of
Staphylococcus aureus on cotton swatches. The photothermal treatment showed higher reduction
efficiency on contaminated textile samples, while the microwave treatment (at 460 W for a period of
60 s) of bio contaminated cotton swatches containing higher moisture content provided satisfactory
bacterial reduction efficiency (more than 7 log steps). Additionally, the treatment of textiles in the
household washing machine with the injection of saturated steam into the washing drum and a mild
agitation rhythm provided at least a 7 log step reduction in S. aureus. The photothermal treatment
of bio contaminated cotton textiles showed promising reduction efficiency, while the microwave
treatment and the treatment with saturated steam proved to be the most effective.
Keywords: household textiles, thermal treatment, decontamination, reduction efficiency
Published in DKUM: 24.03.2025; Views: 0; Downloads: 1
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4. Distributed energy resource operation analysis using discrete event-simulationBojan Rupnik, Dušan Kragelj, Simona Šinko, Tomaž Kramberger, 2020, original scientific article Abstract: This paper presents a discrete-event simulation (DES) approach for simulation of distributed energy resources (DER). The DES approach provides means to adapt the energy workloads of the system according to any variations of demands that can occur due to temperature regulation requirements or operational demands. Along with a basic model based on a concrete DER configuration, additional models are presented and analysed in order to demonstrate the adaptability of the DES approach to analyse alternative configurations. The models were tested on historical energy consumption data in order to provide the expected workloads and costs. Models are capable to predict the amount of three different energies and cost for the company based on the inside and outside temperatures.
Keywords: cost, discrete-event simulation, distributed energy resources, energy efficiency, hospitals, logistics
Published in DKUM: 10.03.2025; Views: 0; Downloads: 8
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5. Clustering patterns in efficiency and the coming-of-age of the cryptocurrency marketHigor Y. D. Sigaki, Matjaž Perc, Haroldo V. Ribeiro, 2019, original scientific article Abstract: The efficient market hypothesis has far-reaching implications for financial trading and market stability. Whether or not cryptocurrencies are informationally efficient has therefore been the subject of intense recent investigation. Here, we use permutation entropy and statistical complexity over sliding time-windows of price log returns to quantify the dynamic efficiency of more than four hundred cryptocurrencies. We consider that a cryptocurrency is efficient within a time-window when these two complexity measures are statistically indistinguishable from their values obtained on randomly shuffled data. We find that 37% of the cryptocurrencies in our study stay efficient over 80% of the time, whereas 20% are informationally efficient in less than 20% of the time. Our results also show that the efficiency is not correlated with the market capitalization of the cryptocurrencies. A dynamic analysis of informational efficiency over time reveals clustering patterns in which different cryptocurrencies with similar temporal patterns form four clusters, and moreover, younger currencies in each group appear poised to follow the trend of their 'elders'. The cryptocurrency market thus already shows notable adherence to the efficient market hypothesis, although data also reveals that the coming-of-age of digital currencies is in this regard still very much underway.
Keywords: cryptocurrency, market efficiency, financial trading, social physics
Published in DKUM: 26.02.2025; Views: 0; Downloads: 2
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6. Development of Methodology for Estimation of Energy-Efficient Building Renovation Using Application of MINLP-Optimized Timber–Glass Upgrade ModulesMaja Lešnik Nedelko, Stojan Kravanja, Miroslav Premrov, Vesna Žegarac Leskovar, 2025, original scientific article Abstract: Vertical addition to already-existing structures is an approach to energy-efficient building renovation. It presents an opportunity for the densification of built-up areas and the construction of new usable spaces. While many studies have dealt with the subject of renovating buildings with a focus on energy efficiency, far fewer studies have specifically examined the potential of vertically extending existing buildings, an approach which could be introduced in new sustainable building policies. The objective of this study is to redevelop optimal timber–glass upgrade modules, considering the ideal proportions of glazing for all cardinal directions, by using discrete Mixed-Integer Non-Linear Programming optimization. The novelty of the suggested method resides in the synchronous optimization of the upgrade modules’ daylighting and energy-efficiency performance, resulting in the creation of optimization methods that can determine the optimal glazing proportions for all cardinal directions and incorporate rational design and window measurement. The impact of the developed Mixed-Integer Non-Linear Programming-optimized upgrade modules is compared to previously designed optimized upgrade modules. Finally, a methodology for estimating the energy efficiency of building renovations incorporating vertical additions using the timber–glass upgrade modules was developed, supporting the quick assessment of the reduction in hybrid buildings’ energy consumption for heating and cooling according to boundary conditions, presuming that they undergo the suggested renovations. The findings are applicable (not exclusively) to Slovenia’s residential building stock, which makes up around 20% of the country’s current housing stock and was mainly constructed between 1946 and 1970. This offers a substantial opportunity to improve the overall sustainability and energy efficiency of the country’s housing stock. The proposed approach offers a holistic solution to drive sustainable development in the built environment by incorporating all three pillars of sustainability (environmental, social, and economic).
Keywords: energy efficient building renovation, energy efficiency, building vertical addition, timber–glass upgrade modules, mixed-integer non-linear programming, MINLP, optimization, visual comfort, energy sustainability
Published in DKUM: 16.01.2025; Views: 0; Downloads: 5
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7. Comparison of different modulation control strategies for wireless power transfer systemJure Domajnko, Oto Težak, Mitja Truntič, Nataša Prosen, 2025, original scientific article Abstract: When designing a wireless power transfer system, overall system efficiency is one of the key parameters. The efficiency depends on several parameters, which also includes control modulation, used for excitation of the transmitter coil. However, how much the modulation technique impacts the efficiency is studied rarely. In this paper, we compare the three most popular control modulation techniques for transmitter voltage of a wireless power transfer system. First, the theory behind the methods is presented by highlighting the difference between them and their implementation. The methods are implemented, together with a linear PI control scheme, to evaluate the efficiency and performance of each of the methods. Finally, the practical tests were performed, under different output power levels, in order to evaluate the practical performance of each modulation strategy further
Keywords: inductive power transfer, full-bridge inverter, inverter modulation comparison, efficiency comparison
Published in DKUM: 08.01.2025; Views: 0; Downloads: 9
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8. Information communication technology and supply chain efficiency in manufacturing SMES in Bulawayo Province in ZimbabweSithokozile Bafana, Simba Mutsvangwa, Felix Chari, 2024, original scientific article Abstract: There has been a global plummeting trend of failure in most manufacturing Small and Medium Enterprises (SMEs) due to purported supply chain inefficiency. It is imperative for clothing manufacturing SMEs in developing nations like Zimbabwe, with reference to Bulawayo Province, which lacks digitization to integrate Information and Communication Technology (ICT) solutions into their supply chain operations to improving efficiency and maintain competitiveness in the global market. Thus, the purpose of the study was to evaluate ICT and supply chain efficiency in the clothing manufacturing SMEs in Bulawayo Province. Employing the pragmatic approach, data were collected using semi-structured questionnaires from a sample of 107 from a total population of 147 that were triangulated with 15 interviews from clothing manufacturing SMEs in Bulawayo. A simple linear regression analysis through Ordinary Least Squares was conducted to test the relationship between ICT and supply chain efficiency. The results show that ICT has a positive and statistically significant effect on cost performance, agility and delivery performance in Bulawayo clothing manufacturing SMEs. By prioritizing ICT adoption, managers can achieve better cost management, increased responsiveness to market demands, and enhanced delivery capabilities. It is recommended that clothing manufacturing SMEs in Bulawayo should embrace the ICT. Further studies should examine the relationship between ICT and supply chain efficiency in manufacturing SMEs across different industries and nations.
Keywords: information and communication technology, supply chain efficiency, SMEs (small and medium enterprises), material requirement planning
Published in DKUM: 17.12.2024; Views: 0; Downloads: 6
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9. The Economic efficiency of micro biogas plants: ǂa ǂSustainable Energy solution in Slovenia - Case studyPeter Vindiš, Karmen Pažek, Jernej Prišenk, Črtomir Rozman, 2024, original scientific article Abstract: This paper presents a simulation model for determining the most suitable type of microbiogas plant for small local communities on Slovenian farms, focusing on the efficient processing of organic waste. This model uses various input parameters, including different types and quantities of slurry and corn silage. Four different scenarios were developed to represent potential plant sizes, each evaluated using key economic indicators: net present value, breakthrough price, and internal rate of return. A scenario sensitivity analysis was conducted to assess the effects of changes in investment costs, fluctuations in energy prices, and the addition of corn silage to the anaerobic digestion process. The results highlight significant differences in economic viability across the scenarios, with some demonstrating positive financial outcomes and shorter payback periods and others indicating potential financial risks and longer recovery times under certain conditions. The analysis suggests that smaller micro biogas plants may struggle to achieve profitability without optimizing input ratios or reducing costs, whereas larger plants show more favorable economic indicators, provided certain conditions are met. Furthermore, the economic efficiency improves when adding maize silage to the fermentor mixture.
Keywords: micro biogas plant, biogas, economic efficiency, simulation
Published in DKUM: 27.11.2024; Views: 0; Downloads: 10
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10. Gender differences in work satisfaction, work engagement and work efficiency of employees during the COVID-19 pandemic : the case in SloveniaMaja Rožman, Simona Sternad Zabukovšek, Samo Bobek, Polona Tominc, 2021, original scientific article Abstract: The COVID-19 pandemic and the resultant lockdown has caused massive economic disruption, leading businesses to make a rapid transition and take a new approach to business strategy. Therefore, the aim of the paper is to examine if there are statistically significant gender differences in work satisfaction, work engagement, and work efficiency among employees who work from home during the COVID-19 pandemic. Further, the paper aims to identify the importance of individual dimensions of work satisfaction, work engagement, and work efficiency, and gender differences perspective. The research is based on a survey of 785 employees in Slovenian companies. The factor analysis and the t-test for two independent samples were used to test the research hypotheses. Findings: The results show significant gender differences in work satisfaction, work engagement, and work efficiency among employees who work from home during the COVID-19 pandemic. The paper provides change management insights and recommendations to assist companies in minimizing the negative impact of the COVID-19 pandemic on their employees.
Keywords: work satisfaction, work engagement, work efficiency, employees, COVID-19
Published in DKUM: 14.10.2024; Views: 0; Downloads: 12
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