Search results for "BAND"
showing 10 items of 2610 documents
VoIP end-to-end performance in HSPA with packet age aided HSDPA scheduling
2008
In this paper, we present an enhanced VoIP scheduling for the high speed downlink packet access (HSDPA) in UMTS, which takes the age of the VoIP packet into account. The downlink capacity can be significantly improved by this way, especially for shorter uplink transmission delay. In order to quantify the achievable performance improvement, we present results obtained from extensive system-level uplink and downlink simulations. Inter alia, it is shown that using the proposed scheme can lead to an increase in the downlink cell capacity of up to 16%. By applying the proposed method, the downlink performance can be improved considerably while the uplink performance remains the same, which ensur…
Optimal configuration for size-based burst assembly algorithms at the edge node for video traffic transmissions over OBS networks
2008
Optical burst switching (OBS) has been proposed to be a technology for implementing the next generation optical Internet. In this architecture, burst assembly algorithms have an important influence in the pattern traffic that characteristic this sort of optical networks. On the other hand, traffic coming from new applications (such as video on demand, Voice over IP, online gaming or Grid computing) that have real time and bandwidth constraints, has been experimented a rapid increment. Consequently, we consider important to evaluate the performance of traffic from real time applications over OBS networks. In this paper, we evaluate the effects of implementing a size-based burst assembly sche…
Effect and optimization of burst assembly algorithms for video traffic transmissions over OBS networks
2008
Optical burst switching (OBS) has been proposed to be a technology for implementing the next generation optical Internet. In this architecture, burst assembly algorithms have an important influence in the traffic pattern that characterizes this sort of optical networks. On the other hand, traffic coming from new applications (such as video on demand, Voice over IP, online gaming or Grid services) that have real time and bandwidth constraints has been experimented a rapid increment. Consequently, we consider important to evaluate the performance of the real time traffic over OBS networks. In this paper, we evaluate the video transmissions performance (MPEG4/RTP/UDP) over OBS networks, for bo…
A FTIR study on low hydration saccharide amorphous matrices: Thermal behaviour of the Water Association Band
2011
Abstract We report a study on the thermal behaviour of the infrared Water Association Band (WAB) in dry binary saccharide–water systems (containing trehalose, sucrose, maltose, and raffinose). This is a follow-up of preceding studies on analogous carboxymyoglobin-saccharide–water ternary systems, which pointed out a mutual protein-matrix influence (coupling). A comparison between binary and ternary systems, for all the saccharides studied, evidences a reduction in the residual water content in the latter and, except for trehalose, a sizable modification in the thermal behaviour, which is discussed in terms of structure and hydrogen bonding properties of the sugars. The study allowed us also…
Broadband telecom to mid-infrared supercontinuum generation in a dispersion-engineered silicon germanium waveguide.
2015
We demonstrate broadband supercontinuum generation (SCG) in a dispersion-engineered silicon-germanium waveguide. The 3 cm long waveguide is pumped by femtosecond pulses at 2.4 μm, and the generated supercontinuum extends from 1.45 to 2.79 μm (at the −30 dB point). The broadening is mainly driven by the generation of a dispersive wave in the 1.5–1.8 μm region and soliton fission. The SCG was modeled numerically, and excellent agreement with the experimental results was obtained.
Investigation of Multipaction Phenomena in Passive Waveguide Filters for Space Applications
2006
This paper presents an investigation on multipaction risk in microwave bandpass filters. The study reveals higher multipaction risk for narrower bandpass filters. To alleviate the problem with multi-paction generation, different novel filtering structures are proposed. Results demonstrate that using the new structures multipaction risk can be reduced as much as 30% with regard to the initial design.
EM Based Synthesis and Design of Bandpass Waveguide Filters Including Manufacturing Effects with FEST3D
2011
This article aims at the industry interest on automated design tools that are able to take into account manufacturing effects. First, an efficient design strategy for bandpass waveguide filters including the rounded corners arising from low-cost manufacturing procedures is presented. This technique is based on a recent enhanced prototype and synthesis methodology able to consider the real structure parts. Using the resulting electromagnetic (EM)-based synthesis technique, an excellent structure is extracted, which requires, at most, only a slight final EM optimization. Second, this article presents analytical expressions providing error estimates for the different filter performances in ter…
A New Planar Microstrip Resonator for Microwave Circuits: The Quasi-Fractal Microstrip Resonator
1999
a new shape for microwave planar circuits using the self-similarity of the fractal geometry is presented. This new shape allows the generation of numerous resonant frequencies for this microwave planar resonator due to the surfaces encasilng. The resonant frequency assessment can be useful to concept specific filters or wide frequency band matching loads as examples, without consuming circuit surface.
<title>Luminescence of intrinsic defects in LiBaF<formula><inf><roman>3</roman></inf></formula></title&g…
2003
A wide emission band in the region of 425 nm is observed in all the examined crystals at photo and ionising irradiation. Maximum of the complex luminescence band is observed at 410 nm at 350 K and at 450 nm at 85 K. The shift of the peak of the band envelope towards shorter wavelengths as the temperature increases is related to thermal dependence of the intensity of elementary components of the luminescence band. The authors suggest that the complex luminescence band arises from electronic excitations at "antisite" defects, i.e., defects caused by stoichiometric deviations, when a portion of Li+ cations (cations of one type of the LiBaF3 crystal lattice) occupy sites of Ba2+ cations (cation…