Joint scheduling and mapping in support of downlink fairness and spectral efficiency in ieee 802.16e OFDMA system

The next generation broadband wireless networks deploy orthogonal frequency division multiple access (OFDMA) as the enabling technologies for broadband data transmission with QoS capabilities. In such broadband wireless systems, one major issue is how to utilize radio resource efficiently while maintaining fairness between sessions as well as providing adequate QoS. In this work, we propose an approach for OFDMA/time division duplex (TDD) downlink suitable for IEEE802.16e WiMAX systems that combines scheduling and burst mapping algorithms for a trade‐off between session fairness, QoS, and spectral efficiency. While optimizing radio resources under QoS and fairness constraints is an NP‐hard problem, we follow a heuristic approach that simplifies the complexity of the algorithm. Performance results show that while the new scheme outperforms the Proportional Fair algorithm in terms of fairness, it also improves the overall system spectral efficiency. Copyright © 2016 John Wiley & Sons, Ltd.     

Enhanced photocatalytic activities of vandium and molybdenum co-doped strontium titanate under visible light

In this report, undoped, mono and co-doped perovskite strontium titanate (SrTi_1−(x+y)Mo_xV_yO₃) were synthesized by the sol-gel method, and their physical and optical properties were investigated. Furthermore, the photocatalytic degradation activities of the synthesized powders were conducted in 10 ppm methylene blue solution under visible-light irradiation. A maximum degradation efficiency of 91.5% was achieved in SrTi_0.9Mo_0.05V_0.05O₃ powder whereas only 59.9% of degradation was found in undoped SrTiO₃. The improved efficiency in co-doped SrTiO₃ was due to the doping of metal cations, Mo⁺⁶ and V⁺⁵ in the host lattice, which created impurity defect states thereby effectively reducing the bandgap energy of the semiconductor.     

Inactivation of pectin Methylesterase and Lactobacillus Plantarum by ohmic heating in pomelo juice

The use of ohmic heating (OH) to inactivate damaging elements in pomelo juice was evaluated. The work investigated the effect of frequencies (50–20 000 Hz) on pectin methylesterase (PME) and Lactobacillus plantarum (L. plantarum) in pomelo juice at 30 V cm⁻¹ of electric field strength. The results show that frequency does not affect PME inactivation (P > 0.05) but affects bacterial reduction and has the most efficiency at 60 Hz, followed by 50 Hz, and in the frequency range at or higher than 500 Hz (P < 0.05). Additionally, the inactivation kinetics of PME and L. plantarum and the impact of nonthermal factors were given. The nonthermal element has contributed to the inactivation enhancement of L. plantarum and PME to reduce the necessary treatment temperature and time. The major spoilage bacteria and enzyme destruction in pomelo juice occurred faster under OH than under conventional heating (CH) suggesting that OH can be effectively used to pasteurise pomelo juice.