LoRaWAN是低功耗广域网(LPWAN)中的一种无线通信标准,为物联网的发展提供了支撑。然而,受限于扩频因子(SF)间不完全正交性的特点和LoRaWAN不具备先听后发(LBT)机制的事实,基于ALOHA的传输调度方式会引发严重的信道冲突,极大降低了LoRa(L...LoRaWAN是低功耗广域网(LPWAN)中的一种无线通信标准,为物联网的发展提供了支撑。然而,受限于扩频因子(SF)间不完全正交性的特点和LoRaWAN不具备先听后发(LBT)机制的事实,基于ALOHA的传输调度方式会引发严重的信道冲突,极大降低了LoRa(Long Range Radio)网络的扩展性。为提高LoRa网络的扩展性,提出用非坚持型载波监听多路访问(NP-CSMA)机制替代LoRaWAN中ALOHA的介质访问控制机制,通过LBT协调LoRa网络中SF相同的各个节点接入信道的时间。不同SF之间的传输则采用多种SF信号并行传输,以减少共信道中同SF干扰和避免SF间干扰。为了分析NP-CSMA对LoRa网络扩展性的影响,通过理论分析和NS3仿真对LoRaWAN与NP-CSMA构建的LoRa网络进行比较。实验结果表明,在相同的条件下,与LoRaWAN相比,NP-CSMA在网络通信负载率为1的情况下,它的理论数据包交付率(PDR)性能比LoRaWAN高58.09%。在信道利用率方面,与LoRaWAN相比,NP-CSMA的饱和信道利用率提高了214.9%,容纳的节点数量也增加了60.0%。另外,NP-CSMA的平均时延在网络通信负载率小于1.7时也低于确认型LoRaWAN,而且在扩频因子为7和10时,它用于维持信道活动检测(CAD)模式所造成的额外能耗也比LoRaWAN用于接收来自网关确认消息所需的额外能耗低1.0~1.3 mJ和2.5~5.1 mJ;充分反映了NP-CSMA可以有效提高LoRa网络的可扩展性。展开更多
AIM To develop a locally adapted, patient-focused transitionprogram, we evaluated the perceptions of adult and adolescent patients and parents regarding transitionprograms and transfer.METHODS We evaluated these perce...AIM To develop a locally adapted, patient-focused transitionprogram, we evaluated the perceptions of adult and adolescent patients and parents regarding transitionprograms and transfer.METHODS We evaluated these perceptions by analyzing the responses of pre-transfer adolescents(n = 57), their parents(n = 57) and post-transfer adults(n = 138) from a cohort of pediatric-liver-transplant-patients using a self-designed questionnaire. Furthermore, we compared a responder group with a non-responder group as well as the provided answers with baseline characteristics and clinical outcomes to exclude selection bias, characterize high-risk patients for nonadherence and test for gender differences. Included in our study were all pre-transfer liver transplant and combined liver-kidney transplant recipients aged 11-19 currently under our care and their parents, as well as all post-transfer liver transplant and combined liverkidney transplant recipients aged ≥ 17 years who had received a liver transplant and were treated at our center during childhood.RESULTS Fifty-seven(24 female) pre-transfer patients who received a transplant in the previous 8-186 mo(mean 93.9 mo, median 92 mo, SD 53.8 mo) and 138(57 female) post-transfer patients who received a transplant in the preceding 2-29 years(mean 15.6 years, median 17, SD 6.90) met the inclusion criteria. A total of 67% of pre-transfer patients(71% of female; 64% of male; P = 0.78) and their parents replied. Additionally, 54% of post-transfer patients(26% of female; 48% of male; P = 0.01) replied. No differences in clinical outcomes were observed between the responder and non-responder groups, and responses did not differ significantly based on clinical complication rates, although they did differ based on gender and the location of medical follow-up after transfer. Adolescents were generally ambivalent toward transition programs. However, adults strongly supported transition programs. CONCLUSION Transition programs need to be developed in close collaboration with adolescents. The best clinical practices regarding transition should respect local circumstances, gender and the location of post-transfer medical follow-up.展开更多
文摘LoRaWAN是低功耗广域网(LPWAN)中的一种无线通信标准,为物联网的发展提供了支撑。然而,受限于扩频因子(SF)间不完全正交性的特点和LoRaWAN不具备先听后发(LBT)机制的事实,基于ALOHA的传输调度方式会引发严重的信道冲突,极大降低了LoRa(Long Range Radio)网络的扩展性。为提高LoRa网络的扩展性,提出用非坚持型载波监听多路访问(NP-CSMA)机制替代LoRaWAN中ALOHA的介质访问控制机制,通过LBT协调LoRa网络中SF相同的各个节点接入信道的时间。不同SF之间的传输则采用多种SF信号并行传输,以减少共信道中同SF干扰和避免SF间干扰。为了分析NP-CSMA对LoRa网络扩展性的影响,通过理论分析和NS3仿真对LoRaWAN与NP-CSMA构建的LoRa网络进行比较。实验结果表明,在相同的条件下,与LoRaWAN相比,NP-CSMA在网络通信负载率为1的情况下,它的理论数据包交付率(PDR)性能比LoRaWAN高58.09%。在信道利用率方面,与LoRaWAN相比,NP-CSMA的饱和信道利用率提高了214.9%,容纳的节点数量也增加了60.0%。另外,NP-CSMA的平均时延在网络通信负载率小于1.7时也低于确认型LoRaWAN,而且在扩频因子为7和10时,它用于维持信道活动检测(CAD)模式所造成的额外能耗也比LoRaWAN用于接收来自网关确认消息所需的额外能耗低1.0~1.3 mJ和2.5~5.1 mJ;充分反映了NP-CSMA可以有效提高LoRa网络的可扩展性。
文摘AIM To develop a locally adapted, patient-focused transitionprogram, we evaluated the perceptions of adult and adolescent patients and parents regarding transitionprograms and transfer.METHODS We evaluated these perceptions by analyzing the responses of pre-transfer adolescents(n = 57), their parents(n = 57) and post-transfer adults(n = 138) from a cohort of pediatric-liver-transplant-patients using a self-designed questionnaire. Furthermore, we compared a responder group with a non-responder group as well as the provided answers with baseline characteristics and clinical outcomes to exclude selection bias, characterize high-risk patients for nonadherence and test for gender differences. Included in our study were all pre-transfer liver transplant and combined liver-kidney transplant recipients aged 11-19 currently under our care and their parents, as well as all post-transfer liver transplant and combined liverkidney transplant recipients aged ≥ 17 years who had received a liver transplant and were treated at our center during childhood.RESULTS Fifty-seven(24 female) pre-transfer patients who received a transplant in the previous 8-186 mo(mean 93.9 mo, median 92 mo, SD 53.8 mo) and 138(57 female) post-transfer patients who received a transplant in the preceding 2-29 years(mean 15.6 years, median 17, SD 6.90) met the inclusion criteria. A total of 67% of pre-transfer patients(71% of female; 64% of male; P = 0.78) and their parents replied. Additionally, 54% of post-transfer patients(26% of female; 48% of male; P = 0.01) replied. No differences in clinical outcomes were observed between the responder and non-responder groups, and responses did not differ significantly based on clinical complication rates, although they did differ based on gender and the location of medical follow-up after transfer. Adolescents were generally ambivalent toward transition programs. However, adults strongly supported transition programs. CONCLUSION Transition programs need to be developed in close collaboration with adolescents. The best clinical practices regarding transition should respect local circumstances, gender and the location of post-transfer medical follow-up.
