为了提高无线通信系统的安全性,基于功率分割型无线携能通信(Power Splitting⁃Simultane⁃ous Wireless Information and Power Transfer,PS⁃SWIPT)模型,提出了一种有源可重构智能表面(Ac⁃tive Reconfigurable Intelligent Surface,ARIS...为了提高无线通信系统的安全性,基于功率分割型无线携能通信(Power Splitting⁃Simultane⁃ous Wireless Information and Power Transfer,PS⁃SWIPT)模型,提出了一种有源可重构智能表面(Ac⁃tive Reconfigurable Intelligent Surface,ARIS)辅助PS⁃SWIPT系统(ARIS⁃PS⁃SWIPT)的安全传输方案。综合考虑ARIS⁃PS⁃SWIPT系统的能量效率和安全性,构造了安全能效最大化问题,通过联合优化基站的波束成形向量、ARIS的反射系数矩阵,以及合法用户的功率分割比值,提升ARIS⁃PS⁃SWIPT系统的安全能效。由于所构建的优化问题为非凸问题,利用交替优化(Alternating Optimiza⁃tion,AO)算法将原问题分解为3个子问题,并进一步通过半正定松弛(Semi⁃Definite Relaxation,SDR)和Dinkelbach方法获得子问题的优化解。仿真结果表明,ARIS⁃PS⁃SWIPT方案在安全能效方面优于PRIS辅助PS⁃SWIPT(PRIS⁃PS⁃SWIPT)方案和放大转发辅助PS⁃SWIPT(AF⁃PS⁃SWIPT)方案,且所提算法相较于遗传算法(Genetic Algorithm,GA),对求解该类问题具备更高的适应性,并且获得了更高的安全能效。展开更多
This article deals with a nonlocal heat system subject to null Dirichlet bound- ary conditions, where the coupling nonlocal sources consist of mixed type asymmetric non- linearities. We at first give the criterion for...This article deals with a nonlocal heat system subject to null Dirichlet bound- ary conditions, where the coupling nonlocal sources consist of mixed type asymmetric non- linearities. We at first give the criterion for simultaneous blow-up of solutions, and then establish the uniform blow-up profiles of solutions near the blow-up time. It is observed that not only the simultaneous blow-up rates of the two components u and v are asymmet- ric, but also the blow-up rates of the same component u （or v） may be in different levels under different dominations.展开更多
Low dissolved oxygen （DO） is an energy- saving condition in activated sludge process. To investi- gate the possible application of limited filamentous bulking （LFB） in sequencing batch reactor （SBR）, two lab-sca...Low dissolved oxygen （DO） is an energy- saving condition in activated sludge process. To investi- gate the possible application of limited filamentous bulking （LFB） in sequencing batch reactor （SBR）, two lab-scale SBRs were used to treat synthetic domestic wastewater and real municipal wastewater, respectively. The results showed that prolonging low DO aeration duration and setting pre-anoxic （anaerobic） phase were effective strategies to induce and inhibit filamentous sludge bulking, respectively. According to the sludge settleability, LFB could be maintained steadily by adjusting operation patterns. Filamentous bacteria content and sludge volume index （SVI） were likely correlated. SVI fluctuated dramatically within a few cycles when around 200 mL-g~, where altering operation pattern could change sludge settleability in spite of the unstable status of activated sludge system. Energy consumption by aeration reduced under low DO LFB condition, whereas the nitrification performance deteriorated. However, short-cut nitrification and simultaneous nitrification denitrification （SND） were prone to take place under such conditions. When the cycle time kept constant, the anoxic （anaerobic） to aerobic time ratio was determining factor to the SND efficiency. Similarity keeping aerobic time as constant, the variation trends of SND efficiency and specific SND rate were uniform. SBR is a promising reactor to apply the LFB process in practice.展开更多
文摘为了提高无线通信系统的安全性,基于功率分割型无线携能通信(Power Splitting⁃Simultane⁃ous Wireless Information and Power Transfer,PS⁃SWIPT)模型,提出了一种有源可重构智能表面(Ac⁃tive Reconfigurable Intelligent Surface,ARIS)辅助PS⁃SWIPT系统(ARIS⁃PS⁃SWIPT)的安全传输方案。综合考虑ARIS⁃PS⁃SWIPT系统的能量效率和安全性,构造了安全能效最大化问题,通过联合优化基站的波束成形向量、ARIS的反射系数矩阵,以及合法用户的功率分割比值,提升ARIS⁃PS⁃SWIPT系统的安全能效。由于所构建的优化问题为非凸问题,利用交替优化(Alternating Optimiza⁃tion,AO)算法将原问题分解为3个子问题,并进一步通过半正定松弛(Semi⁃Definite Relaxation,SDR)和Dinkelbach方法获得子问题的优化解。仿真结果表明,ARIS⁃PS⁃SWIPT方案在安全能效方面优于PRIS辅助PS⁃SWIPT(PRIS⁃PS⁃SWIPT)方案和放大转发辅助PS⁃SWIPT(AF⁃PS⁃SWIPT)方案,且所提算法相较于遗传算法(Genetic Algorithm,GA),对求解该类问题具备更高的适应性,并且获得了更高的安全能效。
基金Supported by the National Natural Science Foundation of China (10771024,11171048)the Education Department Program of Liaoning Province (L2010068)
文摘This article deals with a nonlocal heat system subject to null Dirichlet bound- ary conditions, where the coupling nonlocal sources consist of mixed type asymmetric non- linearities. We at first give the criterion for simultaneous blow-up of solutions, and then establish the uniform blow-up profiles of solutions near the blow-up time. It is observed that not only the simultaneous blow-up rates of the two components u and v are asymmet- ric, but also the blow-up rates of the same component u （or v） may be in different levels under different dominations.
文摘Low dissolved oxygen （DO） is an energy- saving condition in activated sludge process. To investi- gate the possible application of limited filamentous bulking （LFB） in sequencing batch reactor （SBR）, two lab-scale SBRs were used to treat synthetic domestic wastewater and real municipal wastewater, respectively. The results showed that prolonging low DO aeration duration and setting pre-anoxic （anaerobic） phase were effective strategies to induce and inhibit filamentous sludge bulking, respectively. According to the sludge settleability, LFB could be maintained steadily by adjusting operation patterns. Filamentous bacteria content and sludge volume index （SVI） were likely correlated. SVI fluctuated dramatically within a few cycles when around 200 mL-g~, where altering operation pattern could change sludge settleability in spite of the unstable status of activated sludge system. Energy consumption by aeration reduced under low DO LFB condition, whereas the nitrification performance deteriorated. However, short-cut nitrification and simultaneous nitrification denitrification （SND） were prone to take place under such conditions. When the cycle time kept constant, the anoxic （anaerobic） to aerobic time ratio was determining factor to the SND efficiency. Similarity keeping aerobic time as constant, the variation trends of SND efficiency and specific SND rate were uniform. SBR is a promising reactor to apply the LFB process in practice.
