1. Performance Enhancement of Grid Connected Multilevel Inverter Based Wind Energy Conversion System with LVRT Capability Using Optimized Type 2 ANFIS Based DVRCh. Sajan, P. Satish Kumar, Peter Virtič, 2024, izvirni znanstveni članek Opis: A Permanent Magnet Synchronous Generator (PMSG) based Wind Energy Conversion System (WECS) holds significant importance in the realm of Renewable Energy Sources (RES) for several reasons. The permanent magnets in the generator eliminate the need for a separate excitation system, leading to improved efficiency in power conversion. This makes PMSG-based WECS an effective and reliable source of wind energy electricity. The motivation behind the proposed conceptual framework stems from the need to overcome the limitations related to the integration of RES into the power grid, specifically focusing on voltage stability and Low Voltage Ride Through (LVRT) capability of PMSG based WECS. A Dynamic Voltage Restorer (DVR), empowered by an energy storage device, is used to mitigate voltage fluctuations and disturbances. The input DC voltage to the DVR is intricately regulated by a Type 2 Adaptive Neuro Fuzzy Inference System (ANFIS) Controller optimized using the Seagull algorithm, exhibiting intelligent adaptability to dynamic conditions. The rectified output from the WECS transforms an Isolated Flyback converter. Subsequently, a 31-Level Cascaded H-Bridge Multilevel Inverter (CHBMLI) along with a Proportional-Integral (PI) controller aids in generating high-quality AC output. By addressing challenges related to voltage stability and the ability to ride through low-voltage conditions, the proposed work contributes to enhanced grid stability. The use of advanced control techniques, including the Type 2 ANFIS Controller optimized by the Seagull algorithm, adds a layer of intelligent adaptability to changing environmental and grid conditions. A lower Total Harmonic Distortion (THD) Value of 1.29% is shown during the validation of the created system utilizing MATLAB/Simulink, assuring significant LVRT capabilities.
Ključne besede: Permanent Magnet Synchronous Generator (PMSG), Wind Energy Conversion System (WECS), Renewable Energy Sources (RES), Low Voltage Ride Through (LVRT), Type 2 Adaptive Neuro Fuzzy Inference System, 31-Level CHBMLI, Proportional-Integral (PI)
Objavljeno v DKUM: 06.11.2025; Ogledov: 0; Prenosov: 2
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2. The blow-up method applied to monodromic singularitiesBrigita Ferčec, Jaume Giné, 2024, izvirni znanstveni članek Opis: The blow-up method proves its effectiveness to characterize the integrability of the resonant saddles giving the necessary conditions to have formal integrability and the sufficiency doing the resolution of the associated recurrence differential equation using induction. In this work we apply the blow-up method to monodromic singularities in order to solve the center-focus problem. The case of nondegenerate monodromic singularities is straightforward since any real nondegenerate monodromy singularity can be embedded into a complex system with a resonant saddle. Here we apply the method to nilpotent and degenerate monodromic singularities solving the center problem when the center conditions are algebraic.
Ključne besede: monodromic singularity, blow-up, center problem, formal first integral
Objavljeno v DKUM: 25.08.2025; Ogledov: 0; Prenosov: 10
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3. Ethical leadership and management of small- and medium-sized enterprises : the role of AI in decision makingTjaša Štrukelj, Petya Dankova, 2025, izvirni znanstveni članek Opis: The integration of artificial intelligence (AI) within the decision-making processes of small- and medium-sized enterprises (SMEs) presents both significant opportunities and substan- tial ethical challenges. The aim of this paper is to provide a theoretical model depicting the interdependence of organisational decision-making levels and decision-making styles, with an emphasis on exploring the role of AI in organisations’ decision making, based on selected process dimension of the MER model of integral governance and management, particularly in relation to routine, analytical, and intuitive decision-making capabilities. The research methodology employs a comprehensive qualitative analysis of the scientific literature published between 2010 and 2024, focusing on AI implementation in SMEs, ethi- cal decision making in integral management, and regulatory frameworks governing AI use in business contexts. The findings reveal that AI technologies influence decision making across business policy, strategic, tactical, and operative management levels, with distinct implications for intuitive, analytical, and routine decision-making approaches. The analysis demonstrates that while AI can enhance data processing capabilities and reduce human biases, it presents significant challenges for normative–ethical decision making, requiring human judgment and stakeholder consideration. We conclude that effective AI integration in SMEs requires a balanced approach where AI primarily serves as a tool for data collection and analysis rather than as an autonomous decision maker. These insights contribute to the discourse on responsible AI implementation in SMEs and provide practical guidance for leaders navigating the complex interplay between (non)technological capabilities, ethical considerations, and regulatory requirements in the evolving business landscape.
Ključne besede: MER model of integral governance and management, strategic management, management process, intuitive decision making, responsible leadership, small- and medium-sized enterprises (SMEs), artificial intelligence (AI), AI regulatory frameworks, analytical decision making, routine decision making
Objavljeno v DKUM: 15.07.2025; Ogledov: 0; Prenosov: 11
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4. Estimate of the driving force for creep crack growthOtmar Kolednik, Marko Kegl, Nenad Gubeljak, Jožef Predan, 2025, izvirni znanstveni članek Opis: A discussion on the conventional creep crack growth parameters, e.g. the experimental C*-integral, C*exp, or the experimental Ct-integral, Ct,ssc, shows that the physical meaning of these parameters for growing cracks in elastic–plastic, creeping materials is not fully clear. Therefore, a comparison is presented in this paper between the conventional creep crack growth parameters, several J-integral related parameters and the crack driving force (CDF), which has been used in linear elastic and elastic–plastic fracture mechanics. The CDF for elastic–plastic, creeping materials is derived from basic thermodynamic principles and by applying the concept of configurational forces (CFs). A comprehensive numerical study is performed where crack propagation is modelled by alternating creep and crack extension steps at constant loads in a compact tension specimen made of the nickel-base superalloy Waspaloy at a temperature of 700 °C. The CDF is evaluated by a CF-based post-processing procedure after a conventional finite element computation. This procedure is applicable for small-scale creep (ssc-), transition creep (tc-) and “moderate” extensive creep (ec-) conditions. For more pronounced ec-conditions, the procedure might have to be adapted. It is shown that C*exp and Ct,ssc reflect the time derivative of the CDF during the creep stages. In contrast, the variations of the CDF coincide well with that of J-values estimated from the crack-tip opening displacement.
Ključne besede: fracture mechanics, creep crack growth, crack driving force, C*-integral, J-integral, configurational force concept, finite element method
Objavljeno v DKUM: 20.03.2025; Ogledov: 0; Prenosov: 6
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5. Fluid flow simulation with an ▫$ℋ^2$▫ -accelerated boundary-domain integral methodJan Tibaut, Jure Ravnik, M Schanz, 2024, izvirni znanstveni članek Opis: The development of new numerical methods for fluid flow simulations is challenging but such tools may help to understand flow problems better. Here, the Boundary-Domain Integral Method is applied to simulate laminar fluid flow governed by a dimensionless velocity–vorticity formulation of the Navier–Stokes equation. The Reynolds number is chosen in all examples small enough to ensure laminar flow conditions. The false transient approach is utilized to improve stability. As all boundary element methods, the Boundary-Domain Integral Method has a quadratic complexity. Here, the ℋ2 -methodology is applied to obtain an almost linear complexity. This acceleration technique is not only applied to the boundary only part but more important to the domain related part of the formulation. The application of the ℋ2 -methodology does not allow to use the rigid body method to determine the singular integrals and the integral free term as done until now. It is shown how to apply the technique of Guigiani and Gigante to handle the strongly singular integrals in this application. Further, a parametric study shows the influence of the introduced approximation parameters. For this purpose the example of a lid driven cavity is utilized. The second example demonstrates the performance of the proposed method by simulating the Hagen–Poiseuille flow in a pipe. The third example considers the flow around a rigid cylinder to show the behavior of the method for an unstructured grid. All examples show that the proposed method results in an almost linear complexity as the mathematical analysis promisses.
Ključne besede: boundary-domain integral method, velocity–vorticity, adaptive cross approximation, modified helmholtz equation, Yukawa potential, fast multipole method, ℋ-structure
Objavljeno v DKUM: 28.11.2024; Ogledov: 0; Prenosov: 14
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6. A point particle source model for conjugate heat and mass transfer in dispersed two-phase flows by BEM based methodsTimi Gomboc, Jurij Iljaž, Jure Ravnik, Matjaž Hriberšek, 2023, izvirni znanstveni članek Ključne besede: boundary-domain integral method, dispersed two-phase flow, two-way coupling, spherical porous particles, drying
Objavljeno v DKUM: 28.03.2024; Ogledov: 217; Prenosov: 25
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7. Vektorska analizaTina Sovič, Simon Špacapan, 2023, učbenik za višje in visoke šole Opis: V učbeniku Vektorska analiza avtorja, dr. Tina Sovič in dr. Simon Špacapan, predstavita vektorske in skalarne funkcije ene in več spremenljivk. Obravnavata glavne teme iz tega področja, kot so krivulje in ploskve v prostoru, odvod vektorskih funkcij, dvojni in trojni integral, ter krivuljni in ploskovni integral skalarne in vektorske funkcije. Namen učbenika je tudi predstaviti praktične aplikacije teorije vektorskih funkcij na področju inženirske prakse, ki se pojavlja pri reševanju različnih problemov v realnem življenju. Učbenik je opremljen s številnimi grafičnimi prikazi, ki nazorno prikazujejo obravnavano temo, številnimi zgledi, ki na konkretnih primerih prikazujejo uporabo teorije v računskih nalogah, ter nekaterimi vajami, ki so namenjene za samostojno reševanje študentov.
Ključne besede: vektorska funkcija, skalarna funkcija, krivulje, ploskve, mnogoterni integral, krivuljni integral, ploskovni integral
Objavljeno v DKUM: 25.07.2023; Ogledov: 436; Prenosov: 112
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8. Integrabilnost in linearizabilnost persistentnih p : -q resonantnih polinomskih sistemov navadnih diferencialnih enačbMaja Žulj, 2022, doktorska disertacija Opis: Eden izmed osrednjih problemov teorije navadnih diferencialnih enačb je problem integrabilnosti, ki je pomemben za razumevanje bistva teorije diferencialnih enačb in za uporabo diferencialnih enačb pri študiju dinamičnih procesov v realnem svetu. Osrednji problemi te doktorske disertacije so problem središča in z njim povezana integrabilnost ter problem linearizabilnosti p:-q resonantnih sistemov s kvadratnimi nelinearnostmi. Obravnavana je tudi povezava med $p:-q$ resonantnimi sistemi in njim pripadajočimi persistentnimi sistemi.
V uvodu so predstavljeni osnovni pojmi komutativne računske algebre, s poudarkom na lastnostih polinomskih idealov in njihovih raznoterosti. Predstavljene so tudi normalne forme, problem središča in linearizabilnosti sistema ter postopek kompleksifikacije realnih sistemov.
Drugo poglavje je namenjeno posplošitvi pojma p:-q resonantnega središča na persistentno p:-q resonantno središče. Izračunamo vse potrebne in zadostne pogoje za nastop persistentnih središč za pet družin p:-q resonantnih sistemov s kvadratnimi nelinearnostmi. Raziskana je povezava med integrabilnostjo p:-q resonantnih sistemov in integrabilnostjo pripadajočih persistentnih sistemov.
V tretjem poglavju so predstavljeni pogoji za nastop linearizabilnega središča za družino 2:-3 resonantnih sistemov, ki jih dobimo z dekompozicijo raznoterosti ideala, generiranega s količinami linearizabilnosti. Zaradi zahtevnosti izračunov uporabimo pristop, ki temelji na modularni aritmetiki. Za dokazovanje zadostnosti tako pridobljenih pogojev uporabimo več različnih metod, najpogosteje uporabimo metodo, ki temelji na Darbouxjevi teoriji linearizabilnosti.
V zadnjem poglavju obravnavamo relativno nov problem (šibko) persistentnega linearizabilnega središča, ki ga posplošimo na problem (šibko) persistentnega linearizabilnega p:-q resonantnega središča. Obravnavana je povezava med linearizacijsko transformacijo p:-q resonantnega sistema in linearizacijsko transformacijo ustreznega persistentnega p:-q resonantnega sistema. Povezava je ponazorjena na 1:-2 in 2:-3 resonantnih kvadratnih sistemih.
Ključne besede: polinomski sistem NDE, p:-q resonantni sistem, problem integrabilnosti, problem linearizabilnosti, količine integrabilnosti, količine linearizabilnosti, persistentno resonantno središče, prvi integral
Objavljeno v DKUM: 08.06.2022; Ogledov: 717; Prenosov: 73
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9. Nedoslednosti v učbenikih za matematiko : magistrsko deloAnja Pertinač, 2022, magistrsko delo Opis: V magistrskem delu je obravnavan problem nedoslednosti v matematičnih učbenikih za gimnazije, ki so potrjeni za uporabo s strani Ministrstva za izobraževanje, znanost in šport. Magistrsko delo je razdeljeno na poglavja, v katerih so obravnavani posamezni tematski sklopi iz veljavnega učnega načrta. Pri vsakem poglavju so predstavljene vpeljave pojmov iz učnega načrta, kot so zapisane v obravnavanih učbenikih. Izkaže se, da so mnoge med njimi pomanjkljive ali celo nekorektne. V vsakem poglavju je predstavljena tudi možna rešitev, kako vpeljavo narediti korektno.
Ključne besede: nedoslednosti, matematični učbeniki, gimnazijsko izobraževanje, naraščanje in
padanje funkcij, geometrijsko zaporedje, sestavljene funkcije, nedoločeni integral, limita in zveznost funkcije
Objavljeno v DKUM: 26.05.2022; Ogledov: 877; Prenosov: 90
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10. Matematika A : za študente FKKT UMPetra Žigert Pleteršek, Matevž Črepnjak, 2022, učbenik za višje in visoke šole Opis: Visokošolski učbenik predstavlja uvod v matematično analizo na naravoslovno-tehniških fakultetah. Poleg osnovnih pojmov o množicah, logiki in številih so obravnavane realne funkcije in z njimi povezana pojma limite funkcije in zveznosti, ter zaporedja in vrste. Zajete se vsebine diferencialnega računa z aplikacijo odvoda, ter integralni račun.
Ključne besede: logika, množice, realne funkcije, limita in zveznost funkcije, zaporedja, vrste, odvod funkcije, integral
Objavljeno v DKUM: 18.02.2022; Ogledov: 1460; Prenosov: 668
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