this paper aims to assess the quality and accuracy aster dems and the arcgis alogorthms used for hydrologic analyses. to this end, first the plan of drainage networks in the region was extracted from aerial photographs and high resolution satellite images and was set as the real ground. in the next step, using the hydrology tool in arcgis software, raster networks of the region for the whole ca...

Raster maps are widely available on the Internet. Valuable information such as street lines and labels, however, are all hidden in the raster format. To utilize the information, it is important to recognize the line and character pixels for further processing. This paper presents a novel algorithm using 2-D Discrete Cosine Transformation (DCT) coefficients and Support Vector Machines (SVM) to c...

the daily record of geomagnetic variations at any world location typically shows a multitude of irregular changes in the field that represent the superposition of many spectral components whose amplitudes generally increase with increasing period. it has been a long established fact that variations in ground magnetic records are caused by the dynamo action in the upper atmosphere. these daily v...

To analyze intensities of ocular exposure to direct (Eo,dir), reflected (Eo,refl), and diffuse (Eo,diff) ultraviolet (UV) irradiance at different solar elevation angles (SEAs), a rotating manikin and dual-detector spectrometer were used to monitor the intensity of ocular exposure to UV irradiation (Eo) and ambient UV radiation (UVR) under clear skies in Sanya, China. Eo,dir was derived as the d...

S urface solar radiation is a major component of the surface heat budget. Diurnally and seasonally averaged over the entire Earth, 188 ± 7 W m–2 reach the surface to be either absorbed (~165 ± 6 W m–2) or reflected back to the atmosphere (Trenberth et al. 2009; Stephens et al. 2012). Changes in the amount of solar radiation received at the surface are intrinsically tied to the total amount of p...

Maximum power point tracking controller is essential to obtain the maximum power from a solar array in the photovoltaic systems as the PV power module varies with the temperature and solar irradiation. In this paper, several methods for the MPPT of the PV systems are discussed and it can to be used as a Helpful reference for the upcoming MPPT user in the PV applications.