Analytical method to compute capacity improvement of dynamic channel assignment with power control

An analytical method is proposed to compute the capacity improvement of a dynamic channel assignment with power control (DCA/PC). A closed-form expression is derived to calculate the capacity of the DCA/PC, which is improved more than 150% compared with fix channel assignment (FCA) and dynamic channel assignment (DCA) with no power control. The theoretical and simulation results show good agreement, the difference being less than 7%.published_or_final_versio

Performance analysis of dynamic channel assignment for cellular mobile radio systems

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Performance analysis of dynamic channel assignment with queuing and guard channel combined scheme for handoff prioritisation

An analytical method to calculate the performance of dynamic channel assignment with queuing and guard channel combined scheme for handoff prioritisation is proposed. Closed form expressions of the call blocking and handoff failure probability are respectively evaluated. The analytical and simulation results show good agreement.published_or_final_versio

Capacity analysis for mobile cellular systems with distributed dynamic channel assignment

The comprehensive study of the distributed dynamic channel assignment (DDCA) that had been proposed was primarily based on simulation results. The corresponding theoretical analysis is very complex and seldom. In this paper, the mobile cellular system capacity with DDCA under power control (DDCA/PC) has been investigated. By employing the reuse factor 'phantom ' NP, a simple close form expression to approximate the call blocking probability has been derived and the system capacity can thus be quickly carried out. The theoretical results resemble closely to that of the simulation [10]. And the system capacity with DDCA/PC substantially increases more than 200% compared to that of the dynamic channel assignment (DCA) or fix channel assignment (FCA) schemes without power control. Furthermore, the system capacity is increased with the larger DDCA/PC gain under stricter power control and expanse of rearrangements. Finally, it shows rather useful to be applied in a practical mobile cellular system.published_or_final_versio

Luminescence spectra of YAG:Се phosphors synthesized in a field of radiation

The paper presents the measurement results of the luminescence band shape for YAG phosphors upon photoexcitation. It is shown that the position and FWHM does not depend on the excitation technique, but it depends on the phosphor prehistory. The observed difference is assumed to be due to the difference in the structure of nanodefects in phosphors synthesized under different conditions

Exploiting Magnetic Resonance Angiography Imaging Improves Model Estimation of BOLD Signal

The change of BOLD signal relies heavily upon the resting blood volume fraction () associated with regional vasculature. However, existing hemodynamic data assimilation studies pretermit such concern. They simply assign the value in a physiologically plausible range to get over ill-conditioning of the assimilation problem and fail to explore actual . Such performance might lead to unreliable model estimation. In this work, we present the first exploration of the influence of on fMRI data assimilation, where actual within a given cortical area was calibrated by an MR angiography experiment and then was augmented into the assimilation scheme. We have investigated the impact of on single-region data assimilation and multi-region data assimilation (dynamic cause modeling, DCM) in a classical flashing checkerboard experiment. Results show that the employment of an assumed in fMRI data assimilation is only suitable for fMRI signal reconstruction and activation detection grounded on this signal, and not suitable for estimation of unobserved states and effective connectivity study. We thereby argue that introducing physically realistic in the assimilation process may provide more reliable estimation of physiological information, which contributes to a better understanding of the underlying hemodynamic processes. Such an effort is valuable and should be well appreciated

Tectonic affinity of the west Qinling terrane (central China): North China or Yangtze?

[33] Neogene (̃14 Ma) basaltic magmatism has occurred in west Qinling, at the northeastern corner of the Tibetan Plateau. Furthermore, U-Pb ages and Hf isotopic data of xenocrystic zircons indicate that the unexposed Neoarchean (2.7-2.5 Ga) basement beneath the Phanerozoic outcrops in west Qinling has affinities with the southern margin of the north China block. The basement has a complex evolution, including the addition of juvenile mantle material at ̃2.7- 2.4 Ga and 1.1-0.8 Ga and reworking at ̃1.8 Ga and possibly at 1.4 Ga. Phanerozoic thermal events at 320-300 Ma, 230 Ma, and 160 Ma also have affected the basement. We interpret the west Qinling orogenic terrane as originally separated from the north China block, joined to the northern Yangtze block during the Meso-Neoproterozoic, and finally involved in the northward subduction and collision of the Yangtze block in the Paleozoic and early Mesozoic and subsequent lithospheric extension in the Jurassic. © 2010 by the American Geophysical Union.published_or_final_versio

The influence of nano-particle tracers on the slip length measurements by microPTV

Direct measurement of slip length is based on the measured fluid velocity near solid boundary. However, previous micro particle image velocimetry/particle tracking velocimetry (microPIV/PTV) measurements have reported surprisingly large measured near-wall velocities of pressure-driven flow in apparent contradiction with the no-slip hypothesis and experimental results from other techniques. To better interpret the measured results of the microPIV/PTV, we performed velocity profile measurements near a hydrophilic wall (z = 0.25-1.5 mu m) with two sizes of tracer particles (phi 50 nm and phi 200 nm). The experimental results indicate that, at less than 1 mu m from the wall, the deviations between the measured velocities and no-slip theoretical values obviously decrease from 93% of phi 200 nm particles to 48% of phi 50 nm particles. The Boltzmann-like exponential measured particle concentrations near wall were found. Based on the non linear Boltzmann distribution of particle concentration and the effective focus plane thickness, we illustrated the reason of the apparent velocity increase near wall and proposed a method to correct the measured velocity profile. By this method, the deviations between the corrected measured velocities and the no-slip theoretical velocity decrease from 45.8% to 10%, and the measured slip length on hydrophilic glass is revised from 75 nm to 16 nm. These results indicated that the particle size and the biased particle concentration distribution can significantly affect near wall velocity measurement via microPIV/PTV, and result in larger measured velocity and slip length close to wall

Microstructures and resistivity of cuprate/manganite bilayer deposited on SrTiO3 substrate

Thin Yba[SUB2]Cu[SUB3]O[SUB7-δ/La[SUB0.67]Ca[SUB0.33]MnO[SUB3] (YBCO/LCMO) films were grown on SrTiO[SUB3](STO)substrates by magnetron sputtering technique. The microstructures of the bilayers were characterized and a standard four-probe technique was applied to measure the resistivity of the samples. The interdiffusions at the YBCO/LCMO and LCMO/STO interfaces formed two transient layers with the thickness of about 3 and 2 nm, respectively. All the bilayers were well textured along the c axis. At low temperature, the superconductivity can only be observed when the thickness of YBCO is more than 25 nm. When the thickness of YBCO is less than 8 nm, the bilayers show only ferromagnetism. The superconductivity and ferromagnetism perhaps coexist in the bilayer with the YBCO thickness of 12.5 nm. These interesting properties are related to the interaction between spin polarized electrons in the manganites and the cooper pairs in the cuprates. © 2003 American Institute of Physics.published_or_final_versio

Observation of the induced pressure in a hybrid micro/nano-channel

This paper studies the flow characteristics in micro/nano-channels subjected to an applied electric field. The nano-channel flow was observed by means of the fluorescence Calcein. A Fluorescence Concentration Gradient Interface (FCGI) was observed across the nano-channel array. The front of the FCGI was shown to have an analogous parabolic shape. The propagation of this interface reflects indirectly the induced pressure at the micro/nano-channel junction, where the enrichment-depletion processes are known to take place. This induced pressure was predicted by numerical simulations, and this paper gives the first experimental evidence