The extraction of road crossings is often neglected by systems for automatic road extraction. Frequently, crossings arise as by-products of the grouping step. This leads to geometrical inaccuracies and visually and cartographically unsatisfactory results. In this paper, an approach for the improvement of extracted road crossings is presented as well as a method for the external evaluation of th...

We analyze properties of links which have diagrams with a small number of negative crossings. We show that if a nontrivial link has a diagram with all crossings positive except possibly one, then the signature of the link is negative. If a link diagram has two negative crossings, we show that the signature of the link is nonpositive with the exception of the left-handed Hopf link (with possible...

Problem: The number of killed and injured persons in incidents at railway level crossings is generally increasing on the Serbian Railways, particularly at passive crossings. In this paper we researched the direct behaviour of road traffic participants at a conventional railway passive crossing. Method: Direct observational study of drivers’ behaviour at a level crossing. Results: Sixty-one road...

[1] Remote sensing of the entire plasmasphere is routinely accomplished by the Extreme Ultraviolet (EUV) imager on the IMAGE satellite. EUVobserves the helium distribution in the plasmasphere by detecting resonantly scattered solar 30.4-nm ultraviolet radiation. In EUV images the plasmapause is assumed to be the ‘‘ He edge,’’ i.e., the outermost sharp edge where the brightness of 30.4-nm He emi...

Implementation of highway-rail level crossing warning systems, educational programs and research on crossings have all contributed to a steady reduction in the risk of level crossings to North American highway users over the past several decades. Much less attention has been given to understanding the effect of level crossings on train safety and risk. Incidents at highway-rail level crossings ...

Research about crossings is typically about minimization. In this paper, we consider maximizing the number of crossings over all possible ways to draw a given graph in the plane. Alpert et al. [1] conjectured that any graph has a convex straight-line drawing, e.g., a drawing with vertices in convex position, that maximizes the number of edge crossings. We disprove this conjecture by constructin...

This paper applies a nonparametric statistical method, hierarchical tree-based regression (HTBR), to explore train-vehicle crash prediction and analysis at passive highway-rail grade crossings. Using the Federal Railroad Administration (FRA) database, the research focuses on 27 years of train-vehicle accident history in the United States from 1980 through 2006. A cross-sectional statistical ana...

The relation between level crossings, entanglement, and Berry phases is investigated for the Breit-Rabi Hamiltonian of hydrogen and sodium atoms, describing a hyperfine interaction of electron and nuclear spins in a magnetic field. It is shown that the entanglement between nuclear and electron spins is maximum at avoided crossings. An entangled state encircling avoided crossings acquires a marg...

t has been shown that under certain conditions multidimensional signals can be recovered from one-level crossings (e.g. o crossings) However, the accuracy wlth which the locans of the one-level crossings need to .be specified is large ough to limit its applicabllity in practical situations. To ercome this problem, we derive two sampling strategies for construction of multidlmensional signals fr...