1. Analytical model and swapping policy assessment of a vertical lift module – buffer integrated storage systemJakob Marolt, Fabio Sgarbossa, Jesus A. Jimenez, Abhimanyu Sharotry, Tone Lerher, 2024, izvirni znanstveni članek Opis: To meet the rising demands of global trade and e-commerce, efficient warehousing relies on inte-grated and cooperative material handling systems. This paper investigates the extension of VerticalLift Module (VLM) storage capability with a Buffer System and assesses the impact of this integra-tion on performance. We developed an analytical model to calculate the expected dual commandcycles, forming the basis for evaluating the VLM – Buffer integrated storage system’s performance.Our research emphasises minimising unnecessary swaps between the VLM and the Buffer Systemto enhance throughput performance. We introduce the Look Ahead Strategy (LAS) to minimiseinter-system swaps and develop a Binary Integer Program (BIP) to benchmark its performance. Theresults indicate that LAS performs on par with BIP, due to its ability to consider product popular-ity during the final selection of the outbound swapping tote. Through a comprehensive analysisof the analytical model with an empirical correction, utilising Pareto-based order sequences, theresults show deviations of less than 1% on average, affirming the analytical model’s accuracy. Ourresearch provides insights on using the VLM-Buffer integrated storage system, emphasising efficienttote swapping policies like LAS for enhanced warehouse operations, and allows managers to assesssystem performance through scenario-based analyses. Ključne besede: automated warehouses, vertical lift module, toteswapping, analytical and numerical modelling, performance evaluation Objavljeno v DKUM: 11.10.2024; Ogledov: 0; Prenosov: 30
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2. Single-tray VLM vs dual-tray VLM : quantitative throughput comparisonGoran Đukić, Tihomir Opetuk, Brigita Gajšek, Tone Lerher, 2021, izvirni znanstveni članek Opis: In this paper quantitative comparison of resulting throughputs for single-tray and dual-tray VLM devices is presented. Comparison is based on mathematical models for throughput approximating dual command times of VLM's crane, for selected parameters of VLM device (height and crane's velocity) and selected picking times per delivered tray. Analysis showed that throughput increase achieved by using dual-tray VLM's depends mostly on the average picking time relative to the expected dual command time of the VLM's crane. Highest improvements are possible for picking time equal to expected dual command time and amounts over 80%, however for extremely low or high picking times improvements are significantly reduced. Ključne besede: order-picking, throughput model, vertical lift module systems, quantitative analysis, intralogistics, dual-tray VLM, single-tray VLM Objavljeno v DKUM: 12.08.2024; Ogledov: 48; Prenosov: 10
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3. Static model of temperature distribution in a photovoltaic moduleKlemen Sredenšek, Sebastijan Seme, Gorazd Hren, 2021, izvirni znanstveni članek Opis: The primary objective of this paper is to present a static model for calculating the temperature distribution in a photovoltaic module using the finite element method. The paper presents in more detail the theoretical background of solar radiation, heat transfer, and the finite element method. The results of the static model are evaluated using temperature measurements of a photovoltaic model, which were performed at the Institute of Energy Technology, Faculty of Energy Technology, University of Maribor. The results of the regression analysis show a good concurrence between the measured and modelled values of the temperature of the photovoltaic module, especially on days with a higher share of the direct component of solar radiation. Ključne besede: photovoltaic module, temperature distribution, heat transfer, finite element method Objavljeno v DKUM: 13.11.2023; Ogledov: 274; Prenosov: 195
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4. Experimental validation of a thermo-electric model of the photovoltaic module under outdoor conditionsKlemen Sredenšek, Bojan Štumberger, Miralem Hadžiselimović, Sebastijan Seme, Klemen Deželak, 2021, izvirni znanstveni članek Opis: An operating temperature of the photovoltaic (PV) module greatly affects performance and its lifetime. Therefore, it is essential to evaluate operating temperature of the photovoltaic module in different weather conditions and how it affects its performance. The primary objective of this paper is to present a dynamic thermo-electric model for determining the temperature and output power of the photovoltaic module. The presented model is validated with field measurement at the Institute of Energy Technology, Faculty of Energy Technology, University of Maribor, Slovenia. The presented model was compared with other models in different weather conditions, such as clear, cloudy and overcast. The evaluation was performed for the operating temperature and output power of the photovoltaic module using Root-Mean-Square-Error (RMSE) and Mean-Absolute-Error (MAE). The average RMSE and MAE values are 1.75C and 1.14C for the thermal part and 20.34 W and 10.97 W for the electrical part. Ključne besede: dynamic modeling, thermo-electric model, accuracy, measuring device, temperature, output power, PV module Objavljeno v DKUM: 13.11.2023; Ogledov: 380; Prenosov: 100
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5. Some functional equations in banach algebras and an applicationJoso Vukman, 1987, izvirni znanstveni članek Opis: V članku so dokazani rezultati o neki funkcionalni enačbi v kompleksni Banachovi algebri. Eden teh rezultatov je uporabljen pri dokazu abstraktne posplošitve Jordan-Neumannove karakterizacije predhilbertovega prostora. Ključne besede: matematika, funkcionalna analiza, Banachova algebra, Banachova ▫$ast$▫-algebra, vektorski prostor, modul, aditivna funkcija, avtomorfizem, antiavtomorfizem, prehilbertov prostor, mathematics, functional analysis, Banach algebra, Banach ▫$ast$▫-algebra, vector space, module, additive functions, automorphism, antiautomorphism, pre-Hilbert space Objavljeno v DKUM: 10.07.2015; Ogledov: 1384; Prenosov: 97
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