328 research outputs found

    Natuur en milieu

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    Improving Operational Efficiency In EV Ridepooling Fleets By Predictive Exploitation of Idle Times

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    In ridepooling systems with electric fleets, charging is a complex decision-making process. Most electric vehicle (EV) taxi services require drivers to make egoistic decisions, leading to decentralized ad-hoc charging strategies. The current state of the mobility system is often lacking or not shared between vehicles, making it impossible to make a system-optimal decision. Most existing approaches do not combine time, location and duration into a comprehensive control algorithm or are unsuitable for real-time operation. We therefore present a real-time predictive charging method for ridepooling services with a single operator, called Idle Time Exploitation (ITX), which predicts the periods where vehicles are idle and exploits these periods to harvest energy. It relies on Graph Convolutional Networks and a linear assignment algorithm to devise an optimal pairing of vehicles and charging stations, in pursuance of maximizing the exploited idle time. We evaluated our approach through extensive simulation studies on real-world datasets from New York City. The results demonstrate that ITX outperforms all baseline methods by at least 5% (equivalent to $70,000 for a 6,000 vehicle operation) per week in terms of a monetary reward function which was modeled to replicate the profitability of a real-world ridepooling system. Moreover, ITX can reduce delays by at least 4.68% in comparison with baseline methods and generally increase passenger comfort by facilitating a better spread of customers across the fleet. Our results also demonstrate that ITX enables vehicles to harvest energy during the day, stabilizing battery levels and increasing resilience to unexpected surges in demand. Lastly, compared to the best-performing baseline strategy, peak loads are reduced by 17.39% which benefits grid operators and paves the way for more sustainable use of the electrical grid

    The role of macrofauna in the functioning of a sea floor: is there any seasonal, density or functional identity effect?

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    Macrobenthos influences rates and intensities of benthic processes. The way in which these processes are affected depends on their densities and functional characteristics in terms of sediment reworking (bioturbation and bio-irrigation). This study focuses on the importance of three different functional groups (FG) of macrobenthos in the ecosystem processes of the Western Coastal Banks area (Belgian Part of the North Sea). Macrobenthic activity depends on temperature and food availability. Therefore two lab experiments were performed: one before sedimentation of the phytoplankton bloom (spring: low food availability and temperature) and one when organic matter had been settled on the sea bottom (late summer: high food availability and higher temperatures). Single - species treatments of key-species belonging to three different functional groups were added to microcosms at three density levels (average natural, lower and very low) to account for possible density declines. These species are the bivalve Abra alba (FG: biodiffuser), the tube-building polychaete Lanice conchilega (FG: piston-pumper) andthe predatory polychaete Nephthy sp. (FG: regenerator/gallery-diffuser).In both winter - and summertime, L. conchilega had a more pronounced influence on oxygen consumption and release Nephtys sp.. Abra alba appeared to be a more effective sediment reworker than Nephtys sp. in both seasons. In addition, ecosystem functioning (as oxygen consumption by the sediment community and bioturbation) seems to be related to animal densities. As such, a decline of densities (due to anthropogenic or natural disturbances) most probably will decrease the rates of ecosystem functioning in theWestern Coastal Banks area

    Вимоги до матеріалів, що приймаються до друку в збірнику наукових праць "Cучасна українська політика. Політики і політологи про неї"

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    We investigated the temporal variation of pelagic and benthic food sources in the diet of benthic taxa at a depositional site in the Southern Bight of the North Sea by means of fatty acid (FA) biomarkers and compound-specific stable isotope analysis (CSIA). The taxa were the non-selective deposit feeding nematodes (<em>Sabatieria</em> spp. and ‘other nematodes’), and three dominant macrobenthic species: two true suspension-deposit feeders (the bivalve <em>Abra alba</em> and the tube dwelling polychaete <em>Owenia fusiformis</em>) and the suspected predatory mud-dwelling anemone <em>Sagartia</em> sp. These species make up on average 16% (<em>Abra alba</em>), 17% (<em>Sagartia</em> sp.) and 20% (<em>Owenia fusiformis</em>) of the biomass in the <em>Abra alba–Kurtiella bidentata</em> community in this area. Phytoplankton dynamics in the suspended particulate matter of the water column as inferred from cell counts, chlorophyll-<em>a</em> and organic carbon content were clearly visible in sediment and animal FA abundance as well, whereas phytodetritus dynamics in the sediment FA composition were less clear, probably due to patchy distribution or stripping of FA by macrofauna. Nematodes appeared to assimilate mainly Polyunsaturated Fatty Acids (PUFAs) from their sedimentary environment and were further non-selectively accumulating more (<em>Sabatieria</em> spp.) or less (‘other nematodes’) FA from the deposited phytodetritus. In contrast, <em>Abra alba</em> FA composition was consistent with a diatom-dominated diet and consumption of <em>Phaeocystis</em> was observed in <em>Owenia fusiformis,</em> whereas <em>Sagartia</em> sp. showed evidence of a predatory behaviour. While the total FA content in <em>Owenia fusiformis</em> remained constant throughout the year, <em>Sagartia</em> sp. doubled and <em>Abra alba</em> increased its FA level more than 10-fold in response to the organic matter deposition from the phytoplankton bloom. This leads to the conclusion that there is no resource partitioning between non-selective deposit feeding nematodes and the suspension-deposit feeding macrobenthic organisms, suggesting they belong to separate parts of the benthic food web

    Notorious places: image, reputation, stigma: the role of newspapers in area reputations for social housing estates

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    This paper reviews work in several disciplines to distinguish between image, reputation and stigma. It also shows that there has been little research on the process by which area reputations are established and sustained through transmission processes. This paper reports on research into the portrayal of two social housing estates in the printed media over an extended period of time (14 years). It was found that negative and mixed coverage of the estates dominated, with the amount of positive coverage being very small. By examining the way in which dominant themes were used by newspapers in respect of each estate, questions are raised about the mode of operation of the press and the communities' collective right to challenge this. By identifying the way regeneration stories are covered and the nature of the content of positive stories, lessons are drawn for programmes of area transformation. The need for social regeneration activities is identified as an important ingredient for changing deprived-area reputations
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