In this paper,we explore a cooperative decode-and-forward(DF)relay network comprised of a source,a relay,and a destination in the presence of an eavesdropper.To improve physical-layer security of the relay system,we p...In this paper,we explore a cooperative decode-and-forward(DF)relay network comprised of a source,a relay,and a destination in the presence of an eavesdropper.To improve physical-layer security of the relay system,we propose a jamming aided decodeand-forward relay(JDFR)scheme combining the use of artificial noise and DF relaying which requires two stages to transmit a packet.Specifically,in stage one,the source sends confidential message to the relay while the destination acts as a friendly jammer and transmits artificial noise to confound the eavesdropper.In stage two,the relay forwards its re-encoded message to the destination while the source emits artificial noise to confuse the eavesdropper.In addition,we analyze the security-reliability tradeoff(SRT)performance of the proposed JDFR scheme,where security and reliability are evaluated by deriving intercept probability(IP)and outage probability(OP),respectively.For the purpose of comparison,SRT of the traditional decode-and-forward relay(TDFR)scheme is also analyzed.Numerical results show that the SRT performance of the proposed JDFR scheme is better than that of the TDFR scheme.Also,it is shown that for the JDFR scheme,a better SRT performance can be obtained by the optimal power allocation(OPA)between the friendly jammer and user.展开更多
探讨土地利用变化所引发的水质净化演变,对于保护和改善水质,实现可持续发展具有重要意义。以“两湖一库”流域为例,运用PLUS(patch-level land use simulation)模型和InVEST(integrated valuation of ecosystem services and tradeoffs...探讨土地利用变化所引发的水质净化演变,对于保护和改善水质,实现可持续发展具有重要意义。以“两湖一库”流域为例,运用PLUS(patch-level land use simulation)模型和InVEST(integrated valuation of ecosystem services and tradeoffs)模型生态系统服务水质净化模块,基于2000年、2010年和2020年土地利用数据,模拟流域在未来自然发展情景和生态保护情景下的用地类型时空格局变化以及水质净化特征。定量揭示土地利用变化与水质净化功能的响应关系。结果表明:“两湖一库”流域土地类型以耕地为主,2030年在自然发展情景下耕地、林地、草地面积呈下降趋势,建设用地呈上升趋势,生态保护情景可有效保护流域耕地、林地等空间分布和面积;“两湖一库”流域TN、TP输出量以低强度输出为主,2000—2020年TN输出量先增加后减少,TP输出量逐年增加,水质净化能力呈稳中变好的趋势;2030年自然发展情境下TN输出量持续减少,TP输出量呈向上浮动,生态保护情景下TN、TP输出量较自然发展情景下减少,生态保护情景可以增加水质净化能力。生态用地类型可以有效截留N、P进入水体,生态保护情景下有效降低生态用地类型的变化速度,减少TN、TP的输出量,“两湖一库”流域未来规划中应增加生态用地的占比,增加土地类型对TN、TP的截留能力。展开更多
This paper investigates the security and reliability of information transmission within an underlay wiretap energy harvesting cognitive two-way relay network.In the network,energy-constrained secondary network(SN)node...This paper investigates the security and reliability of information transmission within an underlay wiretap energy harvesting cognitive two-way relay network.In the network,energy-constrained secondary network(SN)nodes harvest energy from radio frequency signals of a multi-antenna power beacon.Two SN sources exchange their messages via a SN decode-and-forward relay in the presence of a multiantenna eavesdropper by using a four-phase time division broadcast protocol,and the hardware impairments of SN nodes and eavesdropper are modeled.To alleviate eavesdropping attacks,the artificial noise is applied by SN nodes.The physical layer security performance of SN is analyzed and evaluated by the exact closed-form expressions of outage probability(OP),intercept probability(IP),and OP+IP over quasistatic Rayleigh fading channel.Additionally,due to the complexity of OP+IP expression,a self-adaptive chaotic quantum particle swarm optimization-based resource allocation algorithm is proposed to jointly optimize energy harvesting ratio and power allocation factor,which can achieve security-reliability tradeoff for SN.Extensive simulations demonstrate the correctness of theoretical analysis and the effectiveness of the proposed optimization algorithm.展开更多
Ecosystem services(ESs)refer to the continuous provisioning of ecosystem goods and services that benefit human beings.Over recent decades,rapid urbanization has exerted significant pressure on coastal ecosystems,resul...Ecosystem services(ESs)refer to the continuous provisioning of ecosystem goods and services that benefit human beings.Over recent decades,rapid urbanization has exerted significant pressure on coastal ecosystems,resulting in biodiversity and habitat loss,environmental pollution,and the depletion of natural resources.In response to these environmental challenges,the Sustainable Development Goals(SDGs)were proposed.Given the pressing need to address these issues,understanding the changes in ESs under the SDGs is crucial for formulating specific ecological strategies.In this study,we first analyzed land use and cover change in the Zhejiang coasts of China during 2000–2020.Then,we investigated the spatiotemporal configuration of ESs by integrating carbon storage(CS),soil retention(SR),habitat quality(HQ)and water yield(WY)using the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model.The driving mechanisms of ESs,which varied by space and time,were also explored using the Geo-detector method.The results revealed that,over the past two decades:1)the Zhejiang coasts have experienced a significant increase of 2783.72 km^(2) in built-up land areas and a continuous decrease in farmland areas due to rapid urbanization;2)owing to higher precipitation,extensive vegetation cover,and reduced anthropogenic disturbances,forests emerge as a crucial land use type for maintaining ecosystem services such as HQ,CS,WY,and SR;3)ESs have generally declined across the entire Zhejiang coasts,with a significant decrease observed in the northern areas and an increase in the southern areas spatially;4)the expansion of built-up land areas emerged as the primary factor affecting ecosystem services,while the vegetation factor has been increasingly significant and is expected to become predominant in the near future.Our study provides insights of understanding of ecosystem service theory and emphasizing the importance of preserving biodiversity for long-term sustainable development,and valuable scientific references to support the ecological management decision-making for local governments.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 62271268,Grant 62071253,and Grant 62371252in part by the Jiangsu Provincial Key Research and Development Program under Grant BE2022800in part by the Jiangsu Provincial 333 Talent Project。
文摘In this paper,we explore a cooperative decode-and-forward(DF)relay network comprised of a source,a relay,and a destination in the presence of an eavesdropper.To improve physical-layer security of the relay system,we propose a jamming aided decodeand-forward relay(JDFR)scheme combining the use of artificial noise and DF relaying which requires two stages to transmit a packet.Specifically,in stage one,the source sends confidential message to the relay while the destination acts as a friendly jammer and transmits artificial noise to confound the eavesdropper.In stage two,the relay forwards its re-encoded message to the destination while the source emits artificial noise to confuse the eavesdropper.In addition,we analyze the security-reliability tradeoff(SRT)performance of the proposed JDFR scheme,where security and reliability are evaluated by deriving intercept probability(IP)and outage probability(OP),respectively.For the purpose of comparison,SRT of the traditional decode-and-forward relay(TDFR)scheme is also analyzed.Numerical results show that the SRT performance of the proposed JDFR scheme is better than that of the TDFR scheme.Also,it is shown that for the JDFR scheme,a better SRT performance can be obtained by the optimal power allocation(OPA)between the friendly jammer and user.
文摘探讨土地利用变化所引发的水质净化演变,对于保护和改善水质,实现可持续发展具有重要意义。以“两湖一库”流域为例,运用PLUS(patch-level land use simulation)模型和InVEST(integrated valuation of ecosystem services and tradeoffs)模型生态系统服务水质净化模块,基于2000年、2010年和2020年土地利用数据,模拟流域在未来自然发展情景和生态保护情景下的用地类型时空格局变化以及水质净化特征。定量揭示土地利用变化与水质净化功能的响应关系。结果表明:“两湖一库”流域土地类型以耕地为主,2030年在自然发展情景下耕地、林地、草地面积呈下降趋势,建设用地呈上升趋势,生态保护情景可有效保护流域耕地、林地等空间分布和面积;“两湖一库”流域TN、TP输出量以低强度输出为主,2000—2020年TN输出量先增加后减少,TP输出量逐年增加,水质净化能力呈稳中变好的趋势;2030年自然发展情境下TN输出量持续减少,TP输出量呈向上浮动,生态保护情景下TN、TP输出量较自然发展情景下减少,生态保护情景可以增加水质净化能力。生态用地类型可以有效截留N、P进入水体,生态保护情景下有效降低生态用地类型的变化速度,减少TN、TP的输出量,“两湖一库”流域未来规划中应增加生态用地的占比,增加土地类型对TN、TP的截留能力。
基金supported in part by the National Natural Science Foundation of China under Grant 61971450in part by the Hunan Provincial Science and Technology Project Foundation under Grant 2018TP1018+1 种基金in part by the Natural Science Foundation of Hunan Province under Grant 2018JJ2533in part by Hunan Province College Students Research Learning and Innovative Experiment Project under Grant S202110542056。
文摘This paper investigates the security and reliability of information transmission within an underlay wiretap energy harvesting cognitive two-way relay network.In the network,energy-constrained secondary network(SN)nodes harvest energy from radio frequency signals of a multi-antenna power beacon.Two SN sources exchange their messages via a SN decode-and-forward relay in the presence of a multiantenna eavesdropper by using a four-phase time division broadcast protocol,and the hardware impairments of SN nodes and eavesdropper are modeled.To alleviate eavesdropping attacks,the artificial noise is applied by SN nodes.The physical layer security performance of SN is analyzed and evaluated by the exact closed-form expressions of outage probability(OP),intercept probability(IP),and OP+IP over quasistatic Rayleigh fading channel.Additionally,due to the complexity of OP+IP expression,a self-adaptive chaotic quantum particle swarm optimization-based resource allocation algorithm is proposed to jointly optimize energy harvesting ratio and power allocation factor,which can achieve security-reliability tradeoff for SN.Extensive simulations demonstrate the correctness of theoretical analysis and the effectiveness of the proposed optimization algorithm.
基金Under the auspices of the National Natural Science Fundation (No.41901121,42276234)Open Funding of Zhejiang Collaborative Innovation Center for Land and Marine Spatial Utilization and Governance Research (No.LHGTXT-2024-004)+1 种基金Science and Technology Major Project of Ningbo (No.2022Z181)Key Laboratory of Coastal Zone Exploitation and Protection,Ministry of Natural Resources (No.2023CZEPK04)。
文摘Ecosystem services(ESs)refer to the continuous provisioning of ecosystem goods and services that benefit human beings.Over recent decades,rapid urbanization has exerted significant pressure on coastal ecosystems,resulting in biodiversity and habitat loss,environmental pollution,and the depletion of natural resources.In response to these environmental challenges,the Sustainable Development Goals(SDGs)were proposed.Given the pressing need to address these issues,understanding the changes in ESs under the SDGs is crucial for formulating specific ecological strategies.In this study,we first analyzed land use and cover change in the Zhejiang coasts of China during 2000–2020.Then,we investigated the spatiotemporal configuration of ESs by integrating carbon storage(CS),soil retention(SR),habitat quality(HQ)and water yield(WY)using the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model.The driving mechanisms of ESs,which varied by space and time,were also explored using the Geo-detector method.The results revealed that,over the past two decades:1)the Zhejiang coasts have experienced a significant increase of 2783.72 km^(2) in built-up land areas and a continuous decrease in farmland areas due to rapid urbanization;2)owing to higher precipitation,extensive vegetation cover,and reduced anthropogenic disturbances,forests emerge as a crucial land use type for maintaining ecosystem services such as HQ,CS,WY,and SR;3)ESs have generally declined across the entire Zhejiang coasts,with a significant decrease observed in the northern areas and an increase in the southern areas spatially;4)the expansion of built-up land areas emerged as the primary factor affecting ecosystem services,while the vegetation factor has been increasingly significant and is expected to become predominant in the near future.Our study provides insights of understanding of ecosystem service theory and emphasizing the importance of preserving biodiversity for long-term sustainable development,and valuable scientific references to support the ecological management decision-making for local governments.
