In this paper, a multi-hop relay channel model based on unmanned aerial vehicles(UAVs) is established by taking into account of the propagation loss, shadowing, and multi-path fading. Based on the proposed channel mod...In this paper, a multi-hop relay channel model based on unmanned aerial vehicles(UAVs) is established by taking into account of the propagation loss, shadowing, and multi-path fading. Based on the proposed channel model, the cascaded propagation loss of relay link and the cascaded probability density function(PDF) of channel fading are derived. Moreover, the theoretical performance of the UAV-based relay system, i.e., the outage probability, bit error rate(BER), and channel capacity, is also analysed and derived. Simulation results show agreement with theoretical results for the hill, mountain, and sea scenarios, indicating the accuracy of both the simulations and derivations.展开更多
Despite growing interest in the use of Payments for Ecosystem Services(PES)for both social and ecological benefits,few studies have investigated the feedback and interaction between poverty alleviation and ecosystem p...Despite growing interest in the use of Payments for Ecosystem Services(PES)for both social and ecological benefits,few studies have investigated the feedback and interaction between poverty alleviation and ecosystem protection outcomes.In this study,the poverty reduction effects of PES policies and their subsequent influence on environmental protection outcomes are investigated.To address these questions,222 local rural households who were involved in PES programs from the Habahu National Nature Reserve in western China were interviewed.The results showed that the social and ecological outcomes of PES policies are neither two separate entities nor a trade-off.While rural households are the key participants in PES programs,the social and ecological outcomes of PES policies are closely related to each other.In addition,poverty reduction results could greatly influence ecosystem conservation effects.Livelihood assets,as well as the attitudes of rural households,play important roles in both of the outcomes.This research provides a new perspective that considers the social and ecological benefits of PES policies,and it also calls for an integrated consideration of social and ecological components in tihe design of PES policies to achieve enhanced results both for poverty alleviation and ecosystem conservation.展开更多
基金supported by the National Key Scientific Instrument and Equipment Development Project(Grant No.2013YQ200607)China NSF Grants(Grant No.61631020)+2 种基金Aeronautical Science Foundation of China(Grant No.2017ZC52021)Fundamental Research Funds for the Central Universities(Grant No.NJ20160027)Open Foundation for Graduate Innovation of NUAA(Grant No.kfjj20160412 and kfjj20170405)
文摘In this paper, a multi-hop relay channel model based on unmanned aerial vehicles(UAVs) is established by taking into account of the propagation loss, shadowing, and multi-path fading. Based on the proposed channel model, the cascaded propagation loss of relay link and the cascaded probability density function(PDF) of channel fading are derived. Moreover, the theoretical performance of the UAV-based relay system, i.e., the outage probability, bit error rate(BER), and channel capacity, is also analysed and derived. Simulation results show agreement with theoretical results for the hill, mountain, and sea scenarios, indicating the accuracy of both the simulations and derivations.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.41471092,41501095,4170011561).The view expressed in this document does not reflect the official opinions of donors.Experiments performed in this research comply with the current laws of China.
文摘Despite growing interest in the use of Payments for Ecosystem Services(PES)for both social and ecological benefits,few studies have investigated the feedback and interaction between poverty alleviation and ecosystem protection outcomes.In this study,the poverty reduction effects of PES policies and their subsequent influence on environmental protection outcomes are investigated.To address these questions,222 local rural households who were involved in PES programs from the Habahu National Nature Reserve in western China were interviewed.The results showed that the social and ecological outcomes of PES policies are neither two separate entities nor a trade-off.While rural households are the key participants in PES programs,the social and ecological outcomes of PES policies are closely related to each other.In addition,poverty reduction results could greatly influence ecosystem conservation effects.Livelihood assets,as well as the attitudes of rural households,play important roles in both of the outcomes.This research provides a new perspective that considers the social and ecological benefits of PES policies,and it also calls for an integrated consideration of social and ecological components in tihe design of PES policies to achieve enhanced results both for poverty alleviation and ecosystem conservation.
