for an indoor non-directed line of sight optical wireless communication (nlos-owc) system we investigate the optimized lambertian order (olo) of light-emitting diodes (leds). we firstly derive an expression for the olo from a conventional lambertian led model. then, we analyze the indoor multi-cell nlos-owc channel characteristics including the optical power distribution and the multipath time ...

Application of Magneto-Rheological (MR) dampers in semi-active vibration dynamics control of a multi-cart system is studied. The dynamics and vibration behaviour of a two cart system is investigated mathematically and an experimental test-rig is employed to verify the model, experimentally. The Bouc-Wen model is utilized to represent the mathematical behaviour of MR damper. Different types of s...

erosion and sediment movement phenomena are one of the most complex issues in management of rivers drainage areas that in water projects are very important. that its measurement wants high time and cost. issue of surface runoff in river basin is a complex issue that human knowledge and understanding about its physical laws a viewpoint of some mathematical formulas is limited. in this study to i...

Like glaciers throughout the world, tropical glaciers in the northern Andes have retreated during the last century. In this study, the retreat of Andean glaciers in Colombian and Venezuela has been mapped from Landsat and ASTER images acquired between 1984 and 2004. Glacier retreat has been mapped for three glaciated regions in Columbia, the Sierra Nevada de Santa Marta, the Sierra Nevada del C...

A long-term (1983–2000) global dataset of Earth’s surface daily-integrated UV exposure was developed from a combination of ISCCP-D1 3 h reflectance measurements (in order to resolve the diurnal variation of cloud conditions) and TOMS total ozone amount. The inversion algorithm developed in our previous study was employed with modifications addressing the conversion of visible reflectance to UV ...

Synchronous sampling allows alternating current (AC) quantities, such as the root mean square (RMS) values of voltage and power, to be determined with very low uncertainties (on the order of a few parts of 10 [1]). In this a new mathematical expression for estimating measurement uncertainties in nonideal synchronization with fundamental frequency AC signals is presented. The obtained results we...

This study intended to determine if an acute bout of soccer heading alters postural control and pronounced self-reported symptoms of cerebral concussion. Collegiate soccer players were randomly assigned to one of 2 groups. Each participant completed a baseline postural control assessment prior to heading. Participants either simulated (control group; CG) or performed (experimental group; EG) 10...

BACKGROUND The aim of the present study was to investigate the effect of near-work on lower and higher-order aberrations, and its progression over a 9-month period during the school year. METHODS Data from 24 young-adult myopic eyes, and 24 non-myopic eyes were used in this investigation. The lower-order aberrations, coma, spherical aberration (SA), and total root mean square (RMS) of higher ...

The evaluation of multisegment coordination is important in gaining a better understanding of the gait and physical activities in humans. Therefore, this study aims to verify whether the use of knee sleeves affects the coordination of lower-limb segments during level walking and one-leg hopping. Eleven healthy male adults participated in this study. They were asked to walk 10 m on a level groun...