The best known output-sensitive sequential algorithm for computing the viewshed on a polyhedral terrain from a given viewpoint was proposed by Katz, Overmars, and Sharir 10 , and achieves time complexity O((k + nn(n)) log n) where n and k are the input and output sizes respectively, and () is the inverse Ackermann's function. In this paper, we present a parallel algorithm that is based on the w...

This paper demonstrates a toolkit for multiple observer siting to maximize their joint viewshed, on high-resolution gridded terrains, up to 2402 × 2402, with the viewsheds’ radii of up to 1000. It shows that approximate (rather than exact) visibility indexes of observers are sufficient for siting multiple observers. It also shows that, when selecting potential observers, geographic dispersion i...

0309-1708/$ see front matter 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.advwatres.2013.03.004 ⇑ Corresponding author. E-mail address: [email protected] (M. Kumar). 1 A water year runs from October through September. The water year is us western USA because most precipitation falls during the winter and spring m November through April. Rui Wang , Mukesh Kumar a,⇑, Da...

background: fear of falling is not only a risk factor for falls, but it is also an important clinical predictor of functional decline in older adults. this study identified sex differences in fear of falling and related factors in older adults with low grip strength. methods: the data of 902 older adults from the 2012 korean national survey, conducted as a research project by the korea employme...

We present an approach to determine the credibility of content provided within a visual VGI source such as Flickr. We propose analysing the variability of selected user and photo metadata of geotagged Flickr photos with the location correctness of these images, which is our reference quality measure. These observed user and photo metadata can help to infer the credibility of contributors.

With the increased availability of user generated data, assessing the quality and credibility of such data becomes important. In this article, we propose to assess the location correctness of visually generated Volunteered Geographic Information (VGI) as a quality reference measure. The location correctness is determined by checking the visibility of the point of interest from the position of t...

The Battle of Midway (June 4 – 6, 1942) is considered one of the pivotal naval encounters of the Second World War. The battle has been examined in detail within both popular and scholarly literature, and a common opinion found in virtually all of these examinations is that Japanese search efforts on the morning of June 4, which were intended to determine if any U.S. naval forces were present, w...

An experiment was conducted to determine the effects of ad libitum access to feed and water and the option to mix feed and water, all in the same feeder, on the performance of multiparous lactating sows. Feed and water were made available to sows using a self-fed wet/dry (SFWD) or a hand-fed (HF) feed-water system. In the SFWD system, feed and water were dropped into a common trough area of the...