| publications-1971 |
Peer reviewed articles |
2022 |
Kleanthis Malialis, Christos G. Panayiotou, Marios M. Polycarpou |
Nonstationary data stream classification with online active learning and siamese neural networks |
Neurocomputing |
10.1016/j.neucom.2022.09.065 |
Simulation & Modeling |
Precipitation & Ecological Systems |
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No abstract available |
883484 |
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| publications-1972 |
Peer reviewed articles |
2023 |
Fotis Panetsos, George C. Karras, Kostas J. Kyriakopoulos |
Aerial Transportation of Cable-Suspended Loads With an Event Camera |
IEEE Robotics and Automation Letters |
10.1109/lra.2023.3333245 |
Data Management & Analytics |
Precipitation & Ecological Systems |
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No abstract available |
883484 |
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| publications-1973 |
Peer reviewed articles |
2022 |
Panagiotis Rousseas; George C. Karras; Charalampos P. Bechlioulis; Kostas J. Kyriakopoulos |
Indoor Visual Exploration with Multi-Rotor Aerial Robotic Vehicles |
Sensors |
10.3390/s22145194 |
Simulation & Modeling |
Precipitation & Ecological Systems |
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In this work, we develop a reactive algorithm for autonomous exploration of indoor, unknown environments for multiple autonomous multi-rotor robots. The novelty of our approach rests on a two-level control architecture comprised of an Artificial-Harmonic Potential Field (AHPF) for navigation and a low-level tracking controller. Owing to the AHPF properties, the field is provably safe while guaranteeing workspace exploration. At the same time, the low-level controller ensures safe tracking of the field through velocity commands to the droneâs attitude controller, which handles the challenging non-linear dynamics. This architecture leads to a robust framework for autonomous exploration, which is extended to a multi-agent approach for collaborative navigation. The integration of approximate techniques for AHPF acquisition further improves the computational complexity of the proposed solution. The control scheme and the technical results are validated through high-fidelity simulations, where all aspects, from sensing and dynamics to control, are incorporated, demonstrating the capacity of our method in successfully tackling the multi-agent exploration task. |
883484 |
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| publications-1974 |
Peer reviewed articles |
2022 |
Ăgota Horel, Tibor Zsigmond, SĂĄndor MolnĂĄr, Imre Zagyva, ZsĂłfia Bakacsi |
Long-term soil water content dynamics under different land uses in a small agricultural catchment |
Journal of Hydrology and Hydromechanics |
10.2478/johh-2022-0015 |
Simulation & Modeling |
Precipitation & Ecological Systems |
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Abstract Longer term monitoring of soil water content at a catchment scale is a key to understanding its dynamics, which can assist stakeholders in decision making processes, such as land use change or irrigation programs. Soil water monitoring in agriculturally dominated catchments can help in developing soil water retention measurements, for assessment of land use change, or adaptation of specific land management systems to climate change. The present study was carried out in the Pannonian region (Upper-Balaton, Hungary) on Cambisols and Calcisols between 2015 and 2021. Soil water content (SWC) dynamics were investigated under different land use types (vineyard, grassland, and forest) at three depths (15, 40, and 70 cm). The meteorological data show a continuous decrease in cumulative precipitation over time during the study with an average of 26% decrease observed between 2016 and 2020, while average air temperatures were similar for all the studied years. Corresponding to the lower precipitation amounts, a clear decrease in the average SWC was observed at all the land use sites, with 13.4%, 37.7%, and 29.3% lower average SWC for the grassland, forest, and vineyard sites, respectively, from 2016 to 2020 (measured at the 15 cm depth of the soil). Significant differences in SWC were observed between the annual and seasonal numbers within a given land use (p < 0.05). The lowest average SWC was observed at the grassland (11.7%) and the highest at the vineyard (28.3%). The data showed an increasing average soil temperature, with an average 6.3% higher value in 2020 compared to 2016. The grassland showed the highest (11.3 °C) and the forest soil the lowest (9.7 °C) average soil temperatures during the monitoring period. The grassland had the highest number of days with the SWC below the wilting point, while the forest had the highest number of days with the SWC optimal for the plants. |
862756 |
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| publications-1975 |
Peer reviewed articles |
2023 |
Froukje Maria Platjouw; Ingrid Nesheim; Caroline Enge |
Policy coherence for the protection of water resources against agricultural pollution in the EU and Norway |
RECIEL - Review of European, Comparative & International Environmental Law |
10.1111/reel.12509 |
Simulation & Modeling |
Precipitation & Ecological Systems |
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AbstractThroughout the European Union (EU), agricultural practices contribute significantly to the pollution of water resources by nitrates, phosphorus and pesticides. This article sheds light on the degree of horizontal legal coherence between the main EU legal and policy instruments applicable to the protection of water resources from agricultural pollution. After identifying key coherence challenges at the EU level, the article thoroughly assesses the regulatory and governance approach in Norway. The key question is how certain EUâlevel coherence challenges could be mitigated at a national level through mechanisms aimed at facilitating crossâsectoral coordination and policy coherence. Three types of mechanisms have been selected for this purpose: (i) legal mechanisms, including crossâreferencing and joint institutional responsibility for implementation; (ii) the establishment of platforms for crossâsectoral policy coordination or actor participation; and (iii) the establishment of monitoring and reporting processes that ensure access to information and data sharing. |
862756 |
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| publications-1976 |
Peer reviewed articles |
2022 |
Yonggen Zhang, Lutz WeihermĂŒller, Brigitta Toth, Muhammad Noman, Harry Vereecken |
Analyzing dual porosity in soil hydraulic properties using soil databases for pedotransfer function development |
Vadose Zone Journal |
10.1002/vzj2.20227 |
Data Management & Analytics |
Precipitation & Ecological Systems |
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AbstractCurrent databases of soil hydraulic properties (SHPs) have typically been used to develop pedotransfer functions (PTFs) to estimate water retention [Ξ(h)] assuming a unimodal poreâsize distribution. However, natural soils often show the presence of bimodal to multimodal poreâsize distributions. Here, we used three widely spread databases for PTF development: UNsaturated SOil hydraulic DAtabase (UNSODA) 2.0, Vereecken, and European hydropedological data inventory (EUâHYDI), to analyze the presence of structural effects in both Ξ(h) and hydraulic conductivity [K(h)]. Only undisturbed samples were included in the analysis that contained enough datapoints for both Ξ(h) and K(h) properties, especially in the wet range. Oneâhundred ninetyâtwo samples were suitable for our analysis, which is only 1% of the total samples in the three databases. Results showed that 65% of the samples exhibited a bimodal poreâsize distribution, and bimodality was not limited to fineâtextured but also coarserâtextured soils. The Mualemâvan Genuchten (MvG) expression for both unimodal and bimodal soils was not able to predict the observed unsaturated K. Only a joint fitting of measured Ξ(h) and K(h) functions provided parameter estimates that were able to describe unsaturated K for uniâ and bimodal soils. In addition, we observed a negative relationship between α and n in the case of low sand content (<52%) for both unimodal and bimodal matrix domain properties, contradicting the classical notion. The ratio of α for the macropore and matrix domain was positively correlated with the fraction of macropores and sand content. We anticipate that the results will contribute to deriving PTF for structured soils and avoid unrealistic combinations of MvG parameters. |
862756 |
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| publications-1977 |
Peer reviewed articles |
2022 |
ÄosiÄ-Flajsig, Gorana; KarleuĆĄa, Barbara; VuÄkoviÄ, Ivan; Glavan, MatjaĆŸ |
Significance of hydromorphological and sediment analysis in river basin water quality management |
Environmental sciences proceedings |
10.3390/environsciproc2022021014 |
Data Management & Analytics |
Precipitation & Ecological Systems |
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No abstract available |
862756 |
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| publications-1978 |
Peer reviewed articles |
2023 |
Forio, M.A.E.; Goethals, P.L.M.; Lock, K.; Nguyen, T.H.T..; Damanik-Ambarita, M.N.; Dominguez-Granda, L.; Thas, O. |
Determining Tipping Points and Responses of Macroinvertebrate Traits to Abiotic Factors in Support of River Management |
Biology |
10.3390/biology12040593 |
Data Management & Analytics |
Groundwater |
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Although the trait concept is increasingly used in research, quantitative relations that can support in determining ecological tipping points and serve as a basis for environmental standards are lacking. This study determines changes in trait abundance along a gradient of flow velocity, turbidity and elevation, and develops traitâresponse curves, which facilitate the identification of ecological tipping points. Aquatic macroinvertebrates and abiotic conditions were determined at 88 different locations in the streams of the Guayas basin. After trait information collection, a set of trait diversity metrics were calculated. Negative binomial regression and linear regression were applied to relate the abundance of each trait and trait diversity metrics, respectively, to flow velocity, turbidity and elevation. Tipping points for each environmental variable in relation to traits were identified using the segmented regression method. The abundance of most traits increased with increasing velocity, while they decreased with increasing turbidity. The negative binomial regression models revealed that from a flow velocity higher than 0.5 m/s, a substantial increase in abundance occurs for several traits, and this is even more substantially noticed at values higher than 1 m/s. Furthermore, significant tipping points were also identified for elevation, wherein an abrupt decline in trait richness was observed below 22 m a.s.l., implying the need to focus water management in these altitudinal regions. Turbidity is potentially caused by erosion; thus, measures that can reduce or limit erosion within the basin should be implemented. Our findings suggest that measures mitigating the issues related to turbidity and flow velocity may lead to better aquatic ecosystem functioning. This quantitative information related to flow velocity might serve as a good basis to determine ecological flow requirements and illustrates the major impacts that hydropower dams can have in fast-running river systems. These quantitative relations between invertebrate traits and environmental conditions, as well as related tipping points, provide a basis to determine critical targets for aquatic ecosystem management, achieve improved ecosystem functioning and warrant trait diversity. |
862756 |
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| publications-1979 |
Peer reviewed articles |
2022 |
Tibor Zsigmond, PĂ©ter Braun, JĂĄnos MĂ©szĂĄros, IstvĂĄn Waltner, Ăgota Horel |
Investigating Plant Response to Soil Characteristics and Slope Positions in a Small Catchment |
Land |
10.3390/land11060774 |
Uncategorized |
Wastewater Treatment Plants |
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Methods enabling stakeholders to receive information on plant stress in agricultural settings in a timely manner can help mitigate a possible decrease in plant productivity. The present work aims to study the soilâplant interaction using field measurements of plant reflectance, soil water content, and selected soil physical and chemical parameters. Particular emphasis was placed on sloping transects. We further compared ground- and Sentinel-2 satellite-based Normalized Vegetation Index (NDVI) time series data in different land use types. The Photochemical Reflectance Index (PRI) and NDVI were measured concurrently with calculating the fraction of absorbed photochemically active radiation (fAPAR) and leaf area index (LAI) values of three vegetation types (a grassland, three vineyard sites, and a cropland with maize). Each land use site had an upper and a lower study point of a given slope. The NDVI, fAPAR, and LAI averaged values were the lowest for the grassland (0.293, 0.197, and 0.51, respectively), which showed the highest signs of water stress. Maize had the highest NDVI values (0.653) among vegetation types. Slope position affected NDVI, PRI, and fAPAR values significantly for the grassland and cropland (p < 0.05), while the soil water content (SWC) was different for all three vineyard sites (p < 0.05). The strongest connections were observed between soil physical and chemical parameters and NDVI values for the vineyard samples and the selected soil parameters and PRI for the grassland. Measured and satellite-retrieved NDVI values of the different land use types were compared, and strong correlations (r = 0.761) between the methods were found. For the maize, the satellite-based NDVI values were higher, while for the grassland they were slightly lower compared to the field-based measurements. Our study indicated that incorporating Sentinel-derived NDVI can greatly improve the value of field monitoring and provides an opportunity to extend field research in more depth. The present study further highlights the close relations in the soilâplantâwater system, and continuous monitoring can greatly help in developing site-specific climate change mitigating methods. |
862756 |
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| publications-1980 |
Peer reviewed articles |
2023 |
Alexandra Tsatsou, Niki Frantzeskaki and Simos Malamis |
Nature-based solutions for circular urban water systems: A scoping literature review and a proposal for urban design and planning - |
Journal of Cleaner Production |
10.1016/j.jclepro.2023.136325 |
IoT & Sensors |
Natural Water Bodies |
|
No abstract available |
776643 |
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