Generalized weighted functional proportional mean combining forecasting model and its method of parameter estimation

A new kind of combining forecasting model based on the generalized weighted functional proportional mean is proposed and the parameter estimation method of its weighting coefficients by means of the algorithm of quadratic programming is given. This model has extensive representation. It is a new kind of aggregative method of group forecasting. By taking the suitable combining form of the forecasting models and seeking the optimal parameter, the optimal combining form can be obtained and the forecasting accuracy can be improved. The effectiveness of this model is demonstrated by an example.

Postnatal weight gain in very low birth weight infants in Beijing and the risk of retinopathy of prematurity

AIMTo analyze the low weight gain (WG) from birth to 4 and 6wk of life to predict the development of retinopathy of prematurity (ROP) among very low birth weight (VLBW) preterm babies.METHODSThree hundred and three newborns with VLBW were analyzed. Body weight measurements were recorded weekly. In all patients, the proportion of the WG was defined as the preterm weight measured at the 4th and 6th weeks of life minus the birth weight (BW) divided by the BW. Other risk factors for ROP were also analyzed.RESULTSMean gestational age and mean BW of the whole cohort were 29.56±1.44wk and 1270.58±176.18g respectively. WG proportion at 4wk postnatal age (18.89%±13.58%) were significantly lower in infants with ROP (P=0.003). WG proportion at 6wk was not different between ROP and no ROP group (42.48%±20.36% vs 46.43%±15.65% P=0.118). When all the other risk factors significant for ROP were included in the logistic regression poor WG did not arise as an independent risk factor. Area under the ROC curve was 0.591 (95%CI: 0.515-0.666; P=0.016). For ROP, the best discriminative cutoff of 18.06% of the proportional WG at the 4th week over the BW, sensitivity and specificity values were 67.3% and 50.0% respectively.CONCLUSIONLow WG proportion in the first 4wk of life is maybe an additional predictor of ROP in very low BW infants. Preterm babies with low BW and low WG proportion should be followed closely for ROP.

Improved proportional fair dynamic subcarrier allocation with frugality constraint for SC-FDMA system

With the objective of taking full use of channel resource, we proposed two utility based dynamic subcarrier allocation （DSA） algorithms for the single carrier frequency division multiple access （SC-FDMA） system, which are the proportional fair frugality constrained （PF-FC） algorithm and the weighted proportional fair frugality constrained （WPF-FC） algorithm. The two proposed algorithms are designed under the frugality constraint （FC） control consideration so as to avoid service rate waste and improve the spectrum efficiency. Moreover, the queuing buffer model in this paper is established on a finite size structure rather than the traditional infinite queuing manner, which is more consistent with the practical transmission condition. Simulation results indicate that the two proposed algorithms can both achieve significantly better system rate-sum capacity and quality of service （QoS） performance than their primary algorithms, and are more applicable for the heterogeneous traffic.