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  • Author: Márton Tamás Horváth x
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Abstract

An unexpected expansion of the Eastern Imperial Eagle (Aquila heliaca) population was observed in East Hungary from mountainous habitat into lowlands from 1989 onwards. Here the population markedly increased from 2 to 59 breeding pairs by 2006, while the mountainous population remained more or less stable with 12-17 breeding pairs. At the beginning of the expansion process the nearest neighbour distances between breeding pairs was lower in the mountains than in the lowlands, but presently they are similar, indicating a saturation process in the lowland areas, but no density dependence was revealed on breeding success. During the study period a higher ratio of non-adult pairs was observed in the lowland territories (49%) than in the mountains (22%). We found that both age and habitat influenced breeding success. We also found that age-effect was significant on success rate (i.e. the ratio of pairs that produce at least one chick), while habitat-effect was more evident on fledging success (i.e. the number of fledglings per productive pair). The overall productivity (i.e. number of fledglings per breeding pair) was affected primarily by the age of the pairs, but the interaction term of age x habitat also was significant. We suppose that better feeding possibilities (closer foraging areas and larger prey density) could explain the higher fledging success in the lowlands. We also predicted that pairs inhabiting agricultural areas in the lowlands will have a reduced success rate due to higher human disturbance, together with an age effect of the breeding pairs. Therefore adult pairs probably can habituate to disturbance even if it happens in the close vicinity of their nesting sites.

Abstract

The knowledge of road traffic parameters is of crucial importance to ensure state-of-the-art traffic services either in public or private transport. In our days, a plethora of road traffic data are continuously collected producing historical and real-time traffic information as well. The available information, however, arrive from inhomogeneous sensor systems. Therefore, a data fusion methodology is proposed based on Switching Kalman Filter. The concept enables efficient travel time estimation for urban road traffic network. On the other hand, the method may contribute to a better macroscopic traffic modelling.

Abstract

As highly automated and autonomous vehicles (AVs) become more and more widespread, inducing the change of traffic dynamics, significant changes occur in traditional traffic control. So far, automotive testing has been done mostly in real-world or pure virtual simulation environment. However, this practice is quite obsolete as testing in real traffic conditions can be quite costly, moreover purely simulation based testing might be inadequate for specific goals. Accordingly, a hybrid concept of the Vehicle-inthe-Loop (ViL) was born recently, in accordance with the Hardware-in-the-Loop concept, i.e. in the ViL concept the vehicle is the 'hardware' within the simulation loop. Furthermore, due to the development of software capabilities, a novel approach, the Scenarioin-the-Loop (SciL) concept evolves based on the ViL approach. The paper defines the main purposes and conditions related to implementing ViL and SciL concepts from the perspective of traffic simulation and traffic control.

Abstract

The diet composition of breeding Eastern Imperial Eagles (Aquila heliaca) was analysed in Hungary between 2005 and 2017, and compared with two previously published datasets from the periods of 1982–1991 and 1992–2004. Altogether the distribution of 8543 prey items of 126 different species and 29 other taxa were analysed within a 36-years period. We found that the previously abundant Common Hamster (Cricetus cricetus) became marginal (7.42%), while European Sousliks (Spermophilus citellus) practically disappeared (0.03%) from the diet of Imperial Eagles. Small game species, like the Common Pheasant (Phasianus colchicus) and the Brown Hare (Lepus europaeus) composed a remarkable part of the diet (11.22% and 28.11% respectively), which raised some conflicts with hunters regionally and probably also contributed to the high prevalence of persecution incidents against the eagles. In parallel with the loss of traditional prey species, corvids (13.10%), pigeons (8.90%), waterbirds (6.83%), other rodents (6.71%), Roe Deers (Capreolus capreolus) (5.59%), raptors and owls (4.88%) became regularly detected prey species. The temporal changes of the main prey categories were analysed between 1998 and 2017, when the ratio of Hamster and Pheasant showed significant decrease (-27.29% and -6.38%, respectively). The ratio of Brown Hare also showed slight decrease (-3.98%), but the change was not significant. On the other hand, the ratio of corvids, waterbirds and Roe Deers within the diet showed significant increase (+18.20%, +6.25% and +5.39%, respectively). The observed flexibility in the foraging behaviour of Imperial Eagles greatly facilitate conservation efforts, as they seems to be able to utilize the most abundant prey sources, i.e. they were not depending solely from the status of any single specific prey source. However, eagles could only shift and survive in those regions, where their traditional preys decreased, if alternative species were available for them.