In this paper, we propose a Packet Cache-Forward(PCF) method based on improved Bayesian outlier detection to eliminate out-of-order packets caused by transmission path drastically degradation during handover events in...In this paper, we propose a Packet Cache-Forward(PCF) method based on improved Bayesian outlier detection to eliminate out-of-order packets caused by transmission path drastically degradation during handover events in the moving satellite networks, for improving the performance of TCP. The proposed method uses an access node satellite to cache all received packets in a short time when handover occurs and forward them out in order. To calculate the cache time accurately, this paper establishes the Bayesian based mixture model for detecting delay outliers of the entire handover scheme. In view of the outliers' misjudgment, an updated classification threshold and the sliding window has been suggested to correct category collections and model parameters for the purpose of quickly identifying exact compensation delay in the varied network load statuses. Simulation shows that, comparing to average processing delay detection method, the average accuracy rate was scaled up by about 4.0%, and there is about 5.5% cut in error rate in the meantime. It also behaves well even though testing with big dataset. Benefiting from the advantage of the proposed scheme in terms of performance, comparing to conventional independent handover and network controlled synchronizedhandover in simulated LEO satellite networks, the proposed independent handover with PCF eliminates packet out-of-order issue to get better improvement on congestion window. Eventually the average delay decreases more than 70% and TCP performance has improved more than 300%.展开更多
Purpose： To study the management and evaluate anatomical and functional outcomes of patients with ipsilateral proximal and shaft femoral fractures. Methods： A retrospective, descriptive and analytic study lasted for...Purpose： To study the management and evaluate anatomical and functional outcomes of patients with ipsilateral proximal and shaft femoral fractures. Methods： A retrospective, descriptive and analytic study lasted for ten years and a half ranging from January 1, 2005 to June 30, 2015. The following parameters were studied： epidemiology, fracture char- acteristics, therapeutic, anatomical and functional outcomes. The correlation between different param- eters was analyzed with Fischer test. The significant threshold was defined for p value 〈0.05. Results： Ten medical files were registered. There were 7 men and 3 women, with a sex ratio of 2.33. The average age was 46 years （range： 29-62 years）. It was about traffic road accidents in all cases. Motorcycle -motorcycle and motorcycle-car collision were most frequent. Average admission delay was 7 h （range： 1.5-24 h）. Left side was most reached in 8 cases. According to Garden classification, there was type Ⅲ cervical fracture in 2 cases, type Ⅱ in 1 case and type Ⅳ in 1 case. According to Ender classification, there was type I trochanteric fracture in 3 cases, type Ⅵ in 2 cases and type Ⅶ in 1 case. According to AO classification, there was type A shaft fracture in 6 cases （A2 in 4 cases and A3 in 2 cases）, type B in 2 cases （BI in 1 case and B2 in 1 case） and type C in 2 cases （CI in 1 case and C2 in 1 case）. Average surgical delay was 28.7 days （range： 11-61 days）. For proximal femoral fracture, Moore prosthesis was used in 1 case, blade plate 130° in 2 cases, long Gamma nail in 4 cases, double screwing in 2 cases and dynamic hip screw in 1 case. For shaft femoral fracture, blade plate 95° was used in 3 cases, low compressive plate in 2 cases. Osseous contention was achieved in 4 cases with long Gamma nail and in 1 case with long blade plate 130°. Nonunion of cervical fracture was achieved in 2 cases. The average osseous healing delay was 5.14 months （range： 3-12 months） for proximal femoral fracture and 5 months （range： 3-8 months） for shaft femoral fractures. According to Friedman and Wyman criteria, functional results were good in 4 cases, average in 4 cases and bad in 2 cases. Regarding implants, healing delay showed no statistic difference between one-implant group and two-implant group （p = 0.52）, and among the patients with different functional outcomes （p = 0.52）. Functional outcomes showed no statistic difference between one-implant group and two-implant group （p = 0.46）. Conclusion： Ipsilateral proximal and shaft femoral fractures are relatively uncommon in our daily ac- tivities. It is difficult to recognize proximal femoral fractures which are unnoticed. Results are generally good if the doctors take the two fractures into account in the management.展开更多
基金supported by National High Technology Research and Development Program of China(863 Program,No.2014AA7011005)National Nature Science Foundation of China(No.91438120)
文摘In this paper, we propose a Packet Cache-Forward(PCF) method based on improved Bayesian outlier detection to eliminate out-of-order packets caused by transmission path drastically degradation during handover events in the moving satellite networks, for improving the performance of TCP. The proposed method uses an access node satellite to cache all received packets in a short time when handover occurs and forward them out in order. To calculate the cache time accurately, this paper establishes the Bayesian based mixture model for detecting delay outliers of the entire handover scheme. In view of the outliers' misjudgment, an updated classification threshold and the sliding window has been suggested to correct category collections and model parameters for the purpose of quickly identifying exact compensation delay in the varied network load statuses. Simulation shows that, comparing to average processing delay detection method, the average accuracy rate was scaled up by about 4.0%, and there is about 5.5% cut in error rate in the meantime. It also behaves well even though testing with big dataset. Benefiting from the advantage of the proposed scheme in terms of performance, comparing to conventional independent handover and network controlled synchronizedhandover in simulated LEO satellite networks, the proposed independent handover with PCF eliminates packet out-of-order issue to get better improvement on congestion window. Eventually the average delay decreases more than 70% and TCP performance has improved more than 300%.
文摘Purpose： To study the management and evaluate anatomical and functional outcomes of patients with ipsilateral proximal and shaft femoral fractures. Methods： A retrospective, descriptive and analytic study lasted for ten years and a half ranging from January 1, 2005 to June 30, 2015. The following parameters were studied： epidemiology, fracture char- acteristics, therapeutic, anatomical and functional outcomes. The correlation between different param- eters was analyzed with Fischer test. The significant threshold was defined for p value 〈0.05. Results： Ten medical files were registered. There were 7 men and 3 women, with a sex ratio of 2.33. The average age was 46 years （range： 29-62 years）. It was about traffic road accidents in all cases. Motorcycle -motorcycle and motorcycle-car collision were most frequent. Average admission delay was 7 h （range： 1.5-24 h）. Left side was most reached in 8 cases. According to Garden classification, there was type Ⅲ cervical fracture in 2 cases, type Ⅱ in 1 case and type Ⅳ in 1 case. According to Ender classification, there was type I trochanteric fracture in 3 cases, type Ⅵ in 2 cases and type Ⅶ in 1 case. According to AO classification, there was type A shaft fracture in 6 cases （A2 in 4 cases and A3 in 2 cases）, type B in 2 cases （BI in 1 case and B2 in 1 case） and type C in 2 cases （CI in 1 case and C2 in 1 case）. Average surgical delay was 28.7 days （range： 11-61 days）. For proximal femoral fracture, Moore prosthesis was used in 1 case, blade plate 130° in 2 cases, long Gamma nail in 4 cases, double screwing in 2 cases and dynamic hip screw in 1 case. For shaft femoral fracture, blade plate 95° was used in 3 cases, low compressive plate in 2 cases. Osseous contention was achieved in 4 cases with long Gamma nail and in 1 case with long blade plate 130°. Nonunion of cervical fracture was achieved in 2 cases. The average osseous healing delay was 5.14 months （range： 3-12 months） for proximal femoral fracture and 5 months （range： 3-8 months） for shaft femoral fractures. According to Friedman and Wyman criteria, functional results were good in 4 cases, average in 4 cases and bad in 2 cases. Regarding implants, healing delay showed no statistic difference between one-implant group and two-implant group （p = 0.52）, and among the patients with different functional outcomes （p = 0.52）. Functional outcomes showed no statistic difference between one-implant group and two-implant group （p = 0.46）. Conclusion： Ipsilateral proximal and shaft femoral fractures are relatively uncommon in our daily ac- tivities. It is difficult to recognize proximal femoral fractures which are unnoticed. Results are generally good if the doctors take the two fractures into account in the management.
