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21.
Numerical heat transfer model for swelling intumescent coatings during heating
Andrea Lucherini, Juan P. Hidalgo, Jose L. Torero, Cristian Maluk, 2023, izvirni znanstveni članek

Povzetek: This research study presents a heat transfer model aimed at estimating the thermal and physical response of intumescent coatings. The numerical model is inspired by the outcomes of an experimental study focused on analysing the insulating effectiveness of a commercial intumescent coating for a range of heating conditions and initial coating thickness. The model solves the one-dimensional heat conduction problem using the finite-difference Crank-Nicolson method, and it assumes that the effectiveness of intumescent coatings is mainly dependent on their ability to develop swelled porous char. The coating swelling is implemented in the model by adopting an approach based on expanding the mesh representing the physical domain in proximity to the substrate-coating interface. The model described herein offers researchers and engineers a tool to estimate the heat transfer of swelling intumescent coatings (i.e. in-depth thermal gradient). Outcomes of the analysis shown herein demonstrate that the heat conduction within intumescent coatings is governed by the physical coating swelling and the thermal conditions at the coating-substrate interface. The numerical model shows that its accuracy is highly influenced by the coating thickness ahead of the reaction zone. Consequently, the coating swelling rate plays a key role, while the thermo-physical properties of the intumescent coating have a secondary effect. According to its assumptions, the model defines a quasi-steady-state thermal problem: it is more accurate for conditions close to steady-state (e.g. high heat fluxes), but it loses accuracy for cases characterised by transient phenomena (e.g. phases prior to the onset of swelling and low heat fluxes).
Ključne besede: intumescent coatings, heat transfer, numerical model, swelling, fire safety
Objavljeno v DiRROS: 08.01.2024; Ogledov: 333; Prenosov: 58
.pdf Celotno besedilo (1,21 MB)
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22.
Preverjanje verjetnostne napovedi sanitarnega poseka smreke zaradi podlubnikov v Sloveniji v 2023
Nikica Ogris, Maarten De Groot, 2023, drugi znanstveni članki

Povzetek: Preverili smo zanesljivost verjetnostne napovedi sanitarnega poseka smreke zaradi podlubnikov v Sloveniji v 2023. Verjetnostni model za napoved sanitarnega poseka smreke zaradi podlubnikov je potrdil visoko zanesljivost (AUC modela = 0,89, AUC napovedi = 0,84). Ugotovili smo optimalni prag za verjetnost sanitarnega poseka, ki ga bomo lahko uporabili pri naslednjih napovedih za bolj jasno določitev območij, kjer se bodo potencialno pojavila žarišča smrekovih podlubnikov. Napoved za leto 2023 smo naredili s pragom 0,30, ki pa se je izkazal za prenizkega, saj je bila kar tretjina modelskih celic lažno pozitivnih. Optimalen prag za verjetnostni model v letu 2023 je bil 0,40. Povprečen optimalen prag v obdobju 2020–2023 je bil 0,45, ki ga predlagamo za izdelavo verjetnostne napovedi v naslednjem letu.
Ključne besede: gozdovi, varstvo gozdov, navadna smreka, Picea abies, sanitarni posek, napoved, ogroženost, model, validacija, zmogljivost, zanesljivost, točnost, natančnost, AUC, občutljivost, specifičnost
Objavljeno v DiRROS: 11.12.2023; Ogledov: 457; Prenosov: 171
.pdf Celotno besedilo (791,14 KB)
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23.
Modeliranje izgube uporabnosti in ocena navidezne starosti asfaltnih vozišč na osnovi vizualne ocene stanja
Primož Pavšič, 2022, izvirni znanstveni članek

Povzetek: Pod vplivi prometnih obremenitev in okoljskih vplivov se kakovost vozišč stalno slabša. Z uporabo modificiranega švicarskega indeksa MSI lahko ocenimo in spremljajmo staranje vozišča, sposobnost zagotavljanja njegove funkcije pa lahko opredelimo z izgubo uporabnosti vozišča. Prispevek podaja predlog nove modelne funkcije za opredelitev staranja vozišča oziroma njegove izgube uporabnosti na osnovi vizualne ocene stanja vozišča (MSI) in določitev njegove navidezne starosti glede na predlagani model staranja vozišč.
Ključne besede: vozišče, ocena stanja, MSI, model
Objavljeno v DiRROS: 04.12.2023; Ogledov: 302; Prenosov: 166
.pdf Celotno besedilo (1,39 MB)
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Models for forecasting the traffic flow within the city of Ljubljana
Gašper Petelin, Rok Hribar, Gregor Papa, 2023, izvirni znanstveni članek

Povzetek: Efficient traffic management is essential in modern urban areas. The development of intelligent traffic flow prediction systems can help to reduce travel times and maximize road capacity utilization. However, accurately modeling complex spatiotemporal dependencies can be a difficult task, especially when real-time data collection is not possible. This study aims to tackle this challenge by proposing a solution that incorporates extensive feature engineering to combine historical traffic patterns with covariates such as weather data and public holidays. The proposed approach is assessed using a new real-world data set of traffic patterns collected in Ljubljana, Slovenia. The constructed models are evaluated for their accuracy and hyperparameter sensitivity, providing insights into their performance. By providing practical solutions for real-world scenarios, the proposed approach offers an effective means to improve traffic flow prediction without relying on real-time data.
Ključne besede: traffic modeling, time-series forecasting, traffic-count data set, machine learning, model comparison
Objavljeno v DiRROS: 28.09.2023; Ogledov: 485; Prenosov: 218
.pdf Celotno besedilo (5,05 MB)
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30.
The potential global distribution of an emerging forest pathogen, Lecanosticta acicola, under a changing climate
Nikica Ogris, Rein Drenkhan, Petr Vahalík, Thomas L. Cech, Martin Mullett, Katherine Tubby, 2023, izvirni znanstveni članek

Povzetek: Brown spot needle blight (BSNB), caused by Lecanosticta acicola (Thüm.) Syd., is an emerging forest disease of Pinus species originating from North America and introduced to Europe and Asia. Severity and spread of the disease has increased in the last two decades in North America and Europe as a response to climate change. No modeling work on spread, severity, climatic suitability, or potential distribution has been done for this important emerging pathogen. This study utilizes a global dataset of 2,970 independent observations of L. acicola presence and absence from the geodatabase, together with Pinus spp. distribution data and 44 independent climatic and environmental variables. The objectives were to (1) identify which bioclimatic and environmental variables are most influential in the distribution of L. acicola; (2) compare four modeling approaches to determine which modeling method best fits the data; (3) examine the realized distribution of the pathogen under climatic conditions in the reference period (1971–2000); and (4) predict the potential future global distribution of the pathogen under various climate change scenarios. These objectives were achieved using a species distribution modeling. Four modeling approaches were tested: regression-based model, individual classification trees, bagging with three different base learners, and random forest. Altogether, eight models were developed. An ensemble of the three best models was used to make predictions for the potential distribution of L. acicola: bagging with random tree, bagging with logistic model trees, and random forest. Performance of the model ensemble was very good, with high precision (0.87) and very high AUC (0.94). The potential distribution of L. acicola was computed for five global climate models (GCM) and three combined pathways of Shared Socioeconomic Pathway (SSP) and Representative Concentration Pathway (SSP-RCP): SSP1-RCP2.6, SSP2-RCP4.5, and SSP5-RCP8.5. The results of the five GCMs were averaged on combined SSP-RCP (median) per 30-year period. Eight of 44 studied factors determined as most important in explaining L. acicola distribution were included in the models: mean diurnal temperature range, mean temperature of wettest quarter, precipitation of warmest quarter, precipitation seasonality, moisture in upper portion of soil column of wettest quarter, surface downwelling longwave radiation of driest quarter, surface downwelling shortwave radiation of warmest quarter and elevation. The actual distribution of L. acicola in the reference period 1971–2000 covered 5.9% of Pinus spp. area globally. However, the model ensemble predicted potential distribution of L. acicola to cover an average of 58.2% of Pinus species global cover in the reference period. Different climate change scenarios (five GCMs, three SSP-RCPs) showed a positive trend in possible range expansion of L. acicola for the period 1971–2100. The average model predictions toward the end of the century showed the potential distribution of L. acicola rising to 62.2, 61.9, 60.3% of Pinus spp. area for SSP1-RCP2.6, SSP2-RCP4.5, SSP5-RCP8.5, respectively. However, the 95% confidence interval encompassed 35.7–82.3% of global Pinus spp. area in the period 1971–2000 and 33.6–85.8% in the period 2071–2100. It was found that SSP-RCPs had a little effect on variability of BSNB potential distribution (60.3–62.2% in the period 2071–2100 for medium prediction). In contrast, GCMs had vast impact on the potential distribution of L. acicola (33.6–85.8% of global pines area). The maps of potential distribution of BSNB will assist forest managers in considering the risk of BSNB. The results will allow practitioners and policymakers to focus surveillance methods and implement appropriate management plans.
Ključne besede: brown spot needle blight, BSNB, pines, species distribution model, climate change, biosecurity
Objavljeno v DiRROS: 02.08.2023; Ogledov: 475; Prenosov: 283
.pdf Celotno besedilo (11,59 MB)
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