We study the problem of visibility in polyhedral terrains in the presence of multiple viewpoints. We consider three fundamental visibility structures: the visibility map, the colored visibility map, and the Voronoi visibility map. We study the complexity of each structure for both 1.5D and 2.5D terrains, and provide efficient algorithms to construct them. Our algorithm for the visibility map in...

operations for its analysis. We show that the analysis induced by E is very imprecise. Hence, in Section 5 we refine the domain E into the more precise domain ER for escape analysis. In Section 6, we discuss our prototype implementation and experimental results. Section 7 concludes the paper by highlighting the differences between previous proposals and our own approach. Section 8 contains the ...

One of the most important factors that affects construction costs of highways is the earthwork cost. On the other hand, the earthwork cost strongly depends on the design of vertical alignment or project line. In this study, at first, the problem of vertical alignment optimization was formulated. To this end, station, elevation and vertical curve length in case of each point of vertical intersec...

Introduction: The Alzheimer Disease (AD) is the most common form of dementia that leads to memory impairment. As the oxidative stress plays an important role in AD pathogenesis, the current study aimed at examining the protective effects of Cyperus Rotundus as an antioxidant on amyloid β (Aβ) -induced memory impairment.   Methods: Twenty-eight Wistar male rats received intrahipp...

UNLABELLED The amount of ultraviolet (UV) radiation reaching the earth's surface has increased due to depletion of the ozone layer. Several studies have reported that UV radiation reduces survival of fish larvae. However, indirect and sub-lethal impacts of UV radiation on fish behavior have been given little consideration. We observed the escape performance of larval cod (24 dph, SL: 7.6±0.2 mm...

introduction: a large body of evidence points to oxidative stress as prime candidate mediating the behavioral impairments and memory deficits in alzheimer's disease (ad). it has been demonstrated that hyperoxia preconditioning activates complex endogenous neuroprotective mechanisms including an increase in capacity of antioxidant defence mechanisms. the aim of this study was to investigate...

Terrains for computer graphics have traditionally been modelled with height fields. In the case of procedurally defined terrains, the height field is generated by a displacement map z = f (x,y). Displacement maps, however, do not allow the formation of such terrain features as overhangs, arches or caves. The most flexible approach to model procedural terrain is to consider it as an implicit sur...

We study optimization problems for polyhedral terrains in the presence of data imprecision. An imprecise terrain is given by a triangulated point set where the height component of the vertices is specified by an interval of possible values. We restrict ourselves to terrains with a one-dimensional projection, usually referred to as 1.5-dimensional terrains, where an imprecise terrain is given by...