3D positioning scheme exploiting nano-scale IR-UWB orthogonal pulses

Abstract

In these days, the development of positioning technology for realizing ubiquitous environments has become one of the most important issues. The Global Positioning System (GPS) is a well-known positioning scheme, but it is not suitable for positioning in in-door/building environments because it is difficult to maintain line-of-sight condition between satellites and a GPS receiver. To such problem, various positioning methods such as RFID, WLAN, ZigBee, and Bluetooth have been developed for indoor positioning scheme. However, the majority of positioning schemes are focused on the two-dimension positioning even though three-dimension (3D) positioning information is more useful especially in indoor applications, such as smart space, U-health service, context aware service, etc. In this paper, a 3D positioning system based on mutually orthogonal nano-scale impulse radio ultra-wideband (IR-UWB) signals and cross array antenna is proposed. The proposed scheme uses nano-scale IR-UWB signals providing fine time resolution and high-resolution multiple signal specification algorithm for the time-of-arrival and the angle-of-arrival estimation. The performance is evaluated over various IEEE 802.15.4a channel models, and simulation results show the effectiveness of proposed scheme.

Volumetric solar heating of nanofluids for direct vapor generation

“…Here, the nanofluid operates similarly to a surface absorber, since a tuned nanofluid will absorb sunlight at the surface for maximum heat concentration. A nanofluid-based absorber may have comparative advantages in high flux applications, due to its ability to increase critical heat flux [40,72] In the future, it would be interesting to investigate methods to further increase the temperature of the generated vaporviavapor flow restriction. By confining the vapor escape from the nanofluid receiver, the evaporation heat transfer and overall heat transfer coefficient of the entire device decreases, increasing the temperature of the fluid within.…”

Influence of the structure defects on the magnetic properties of the FePt/Fe bilayer

“…Recently a plenty of theoretical studies have been done [17], [18], [19] and a number of experiments has been performed on FePt-based systems such as exchangecoupled L1 0 FePt/[Co/Ni] N [20], FePt/[Co/Pt] [21], FePt/Fe 3 Pt [6] nanocomposite multilayers, FePt/CoCrNi [22], FePt/FeRh [23], FePt/CoFeTaB [24] bilayers, FePt thin films on Si [25] and CrV [26] substrate, FePt nanoparticles [27], [28], FePt/Fe thin films [29], [30], [31], [32], [33], [34]. Among them, FePt/Fe system has shown unique magnetic values.…”

The influence of three-dimensional capillary-porous coatings on heat transfer at liquid boiling

“…[1]. In recent years, much attention has been also devoted to using nanofluids representing colloids with small additives of nanoparticles of metals (Cu, Ag), oxides (Al 2 O 3 , CuO, SiO 2 , TiO 2 ), or carbon (nanodiamonds, nanotubes) with dimensions within 10-500 nm, which improve heat transfer and increase the critical heat flux (CHF) in pool boiling [2][3][4]. It has been repeatedly pointed out (e.g., see [4][5][6]) that the main effect on CHF (1.5-to 2-fold increase) in boiling nanofluids is related to the deposition of nanoparticles on the heat-exchanger surface and the formation of a porous coating.…”