Both airborne and terrestrial laser scanners are used to capture large point clouds of the objects under study. Although for some applications, direct measurements in the point clouds may already suffice, most applications require an automatic processing of the point clouds to extract information on the shape of the recorded objects. This processing often involves the recognition of specific ge...

There are plenty of applications about real-time simulation of realistic clouds. In this paper, the model of the clouds is established based on cellular automata and the method of how to deal with boundary grid points is developed. The efficiency is enhanced and some of the dynamic aspects of clouds are described by using promoted transition rules and introduced ascending air current. Multiple ...

Previous attempts at disturbing the galactic disk by the Magellanic Clouds relied on direct tidal forcing. However, by allowing the halo to actively respond rather than remain a rigid contributor to the rotation curve, the Clouds may produce a wake in the halo which then distorts the disk. Recent work reported here suggests that the Magellanic Clouds use this mechanism to produce disk distortio...

Interstellar space is not empty, but contains gaseous and particulate matter that is concentrated into very large regions known as interstellar clouds. In the denser and cooler clouds, the gas is molecular and most of the molecules detected are organic in nature. The gas-phase molecules are synthesised from precursor atoms by rapid exothermic reactions in the gas and on the surfaces of tiny dus...

We re-examine critically the estimates of the duration of different phases of star formation and the lifetimes of molecular clouds, based on the ages of T-Tauri stars, age spreads of stars in clusters, and statistics of pre-stellar cores. We show that all available observational data are consistent with lifetimes of molecular clouds comparable to ≈ 10 yr, as well as with the predictions of the ...

High Velocity Clouds (HVCs) have recently attracted renewed attention as being long lived, massive dark matter dominated clouds of primordial composition distributed throughout the Local Group. In this picture the HVCs would contain a few ×10 M⊙ of H i and would be at distances of a few hundred kpc to 1.5 Mpc from the Local Group barycenter. If this extragalactic interpretation of HVCs is true,...

By a cloud we mean an infrastructure that provides resources or services over a network, often the Internet, usually at the scale and with the reliability of a data center. We distinguish between clouds that provide on-demand computing instances (such as Amazon’s EC2 service) and clouds that provide on-demand computing capacity (such as provided by Hadoop). We give a quick overview of clouds an...

This paper presents an efficient method based on physical laws to model volcanic clouds. Some physical models have been proposed for simulating volcanic clouds [Woods 1988], but most of the previous models are only two or less dimensional or need huge calculation times. Our approach achieves a physical, 3D and efficient modeling of volcanic clouds. The dynamics of volcanic clouds is modeled usi...

We confirm and discuss recently discovered cold HI clouds with column densities among the lowest ever detected. The column densities of Cold Neutral Medium (CNM) towards 3C286 and 3C287 are ∼ 10 cm, below an observational lower limit, and also below tiny-scale-atomic clouds detected by VLBI and time-variable profiles against pulsars. These column densities are close to the minimum imposed by th...

We evaluate the "indirect," i.e., cloud-induced, shortwave effect of anthropogenic sulfate aerosols in marine stratocumulus clouds. The latter have a pronounced climatic effect due to their high reflectivity compared to the sea surface, large global coverage, and near-absence of greenhouse effects. The indirect effect is thought to be less pronounced in continental clouds, in part because these...