Modeling and Simulation of Packet Delivery Rate in LTE-V Network Based on Markov Chain

As one of the most promising communication technologies for vehicular networks, LTE-V has the advantages of wide coverage and a high transmission rate. 3 GPP released the technical specification of LTE-V in March 2017, launching a spate of related research and industrialization. In this paper, we propose a communication model based on Markov process to evaluate the reliability of LTE-V. We derived the Packet Delivery Rate(PDR) of LTE-V based on the model. Moreover, we use Poisson process to model the distribution of vehicles on a highway,then combine the communication model with the vehicles’ distribution to derive the PDR under this scenario. To verify the correctness of the proposed model, we established a simulation program on the MATLAB platform. By comparing the simulation results and the mathematical results, we found that simulation results are a very good fit for the model.

Pregnancy outcomes following supplementation of single dose GnRH agonist to sustain the luteal phase in antagonist fresh embryo transfer cycles:A multicentric prospective cohort study

Objective:To determine whether a single dose of gonadotropin-releasing hormone(GnRH)agonist administered subcutaneously in addition to the regular progesterone supplementation could provide a better luteal support in antagonist protocol fresh embryo transfer cycles.Methods:This prospective,multicentric,cohort study included total 140 women,70 in each group.Controlled ovarian stimulation was carried out as per fixed GnRH antagonist protocol.The trigger was given with hCG.In vitro fertilization/intracytoplasmic sperm injection(IVF/ICSI)was performed and day-3 embryos were transferred.Patients were divided into groups 1 and 2 based on computer generated randomization sheet.Six days following oocyte retrieval,group 1 received 0.2 mg decapeptyl subcutaneously in addition to regular progesterone support while group 2 received progesterone only.Luteal support was given for 14 days to both groups;if pregnancy was confirmed luteal support was continued till 12 weeks of gestation.The clinical pregnancy rate was the primary outcome.The implantation rate,miscarriage rate,live birth delivery rate,and multiple pregnancy rates were the secondary outcomes.Results:A total of 140 patients were analysed,70 in each group.Clinical pregnancy rates(47.1%vs.35.7%;P=0.17),implantation rates(23.4%vs.18.1%,P=0.24),live birth delivery rates(41.4%vs.27.1%,P=0.08),and multiple pregnancy rates(21.2%vs.16.0%,P=0.74)were higher in group 1 than in group 2.Group 1 had a lower miscarriage rate than group 2(5.7%vs.8.6%;P=0.75).However,these differences were not statistically significant between the two groups.Conclusions:Administration of a single dose of GnRH agonist in addition to regular natural micronized vaginal progesterone as luteal support in GnRH antagonist protocol cycles marginally improves implantation rates,clinical pregnancy rates,and live birth delivery rates.However,more studies with higher sample sizes are needed before any conclusive statements about GnRH agonist as luteal phase support can be made.

Enhanced lakebed sediment erosion in Dongting Lake induced by the operation of the Three Gorges Reservoir

Based on field-survey hydrological series in the Dongting Lake watershed from 1951 to 2011, the variations of lakebed sediment siltation/erosion（S/E） regimes of the Dongting Lake after the operation of the Three Gorges Reservoir（TGR） were analyzed. Significantly positive correlations were found between the flow rate from Zhicheng and the Three Outlets（r^2=0.859, p〈0.0001）, and between the flow rate and sediment delivery rate at the Three Outlets（r^2=0.895, p〈0.0001）. This indicated that the flow rate and sediment delivery rate at the Three Outlets were largely determined by the flow rate from the upstream Yangtze River. Sediment deposition amount in the Dongting Lake basin dropped from ＋4796.4×10^4 t during the period before the operation of TGR（1999–2002） to ＋684.1×10^4 t, ＋449.8×10^4 t and –559.6×10^4 t during the impoundment Phases I, II and III of TGR. The S/E regimes changed from a siltation-dominant to an erosion-dominant state under the pre-discharge, water-storage and water-supplement dispatch over the impoundment from Phase I to III. The sediment deposition amount decreased dramatically under the flood-storage dispatch over the impoundment Phase I to III. The estimated annual mean flow rate, sediment delivery rate and sediment concentration thresholds were respectively 970.81 m3/s, 466.82 kg/s and 0.481 kg/m3 for the upstream Three Outlets to maintain an erosion-dominant state in the downstream linked the Dongting Lake.

Experimental characterization of the removal efficiency and energy effectiveness of central air cleaners

This study assessed six commercially available in-duct air cleaning devices which are designed to be mounted in the central ventilation system of offices or commercial buildings.The selected devices use different air cleaning technologies:mechanical filtration,electrostatic precipitation,gas filtration,ionization/cold plasma,photocatalytic oxidation(PCO)and catalysis under UV light.They were tested against particles,a mixture of volatile organic compounds containing acetone,acetaldehyde,toluene,heptane and formaldehyde,and two bio-contaminants:Aspergillus brasiliensis(fungus)and Staphylococcus epidermidis(bacteria).Two different test rigs were used.The single pass efficiency of each device was determined for three airflow rates,corresponding to face velocities ranging from 0.9 to 2.7 m/s,and two sets of temperature and humidity that are representative of indoor air conditions in wintertime and summertime.The concentration of the chal-lenge volatile organic compounds was also varied in the 30 to 100μg/m^(3)range as a way to characterize their influence on efficiency at realistic concentration levels for non-industrial buildings.Measurements of ozone and formaldehyde concentration downstream of the air cleaners were carried out to determine the emission rate of by-products into the air stream.Finally,the energy issue was addressed by measuring the electric power drawn and pressure loss of the devices.The results showed that two devices,namely a radiant catalytic ionizer and a plasma ionizer,had a very low single pass efficiency against all the challenge pollutants.The association of the plasma ionizer and the electrostatic precipitator did not produce a synergetic effect between the two technologies either,contrary to what their manufacturer claims.Finally,three of the six devices tested were effective in terms of pollutant removal,but only two had an acceptable energy effectiveness in view of their use in low or zero energy buildings.Their energy effectiveness ranged from a few thousand m^(3)/kWh for VOCs at the highest airflow rate(3600 m^(3)/h),to more than 60000 m^(3)/kWh for particles and bio-contaminants at 1200 or 1600 m^(3)/h.These results are at least one order of magnitude higher than the majority of stand-alone air cleaners.Moreover,they suggest that optimal IAQ and energy conditions can be achieved if variable air volume control methods are used to maintain indoor temperature and humidity.