Non-Line-of-Sight(NLOS)Ultraviolet(UV)communication uses the atmosphere as a propagation medium.As the communication range increases,turbulence becomes a significant atmospheric process that affects the propagation of...Non-Line-of-Sight(NLOS)Ultraviolet(UV)communication uses the atmosphere as a propagation medium.As the communication range increases,turbulence becomes a significant atmospheric process that affects the propagation of optical waves.This paper presents a more accurate NLOS channel model by considering turbulence-induced Scintillation Attenuation(SA).Then,the Bit Error Rate(BER)during turbulence of the NLOS UV communication system with On-Off Keying(OOK)modulation and Maximum Likelihood(ML)detection is analysed and compared with that in free space without turbulence.The BER dependence is also analysed for different factors,including the refractive index structure parameter,transceiver range,pointing angles,transmitted power,and data rate.展开更多
In 2013 a new collaborative center was established in Wellington, New Zealand to focus on integrating resilience research with the region’s community disaster resilience strategy. An earlier study with parties to thi...In 2013 a new collaborative center was established in Wellington, New Zealand to focus on integrating resilience research with the region’s community disaster resilience strategy. An earlier study with parties to this center had indicated that researcher and practitioner groups were divided by attention to their own immediate knowledge and skills, but agreed there was a need to maximize community resilience benefits amongst a regional population. An action research workshop of researchers and practitioners used a visual logic model to focus on the pragmatic benefits of improving community resilience. The visual logic model was used to design research activities that would improve the regional community resilience strategy, which was still in an early implementation phase.Ten of 14 workshop participants were interviewed following the workshop. Statistical content analysis of interview data highlighted certain strengths of the action research process: visual monitoring and evaluation planning was a catalyst for complicated conversations between two very different groups of professionals; and researchers became more focused on practical issues as a result. Other findings suggested that in future collaborative researchgovernance would benefit from wider cycles of strategic intelligence, enhanced research contributions, and the use of different information formats for different purposes.Different formats for different purposes should also be considered when developing and implementing large-scale disaster risk reduction policies and strategies.展开更多
基金supported by the Open Fund of State Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications),China
文摘Non-Line-of-Sight(NLOS)Ultraviolet(UV)communication uses the atmosphere as a propagation medium.As the communication range increases,turbulence becomes a significant atmospheric process that affects the propagation of optical waves.This paper presents a more accurate NLOS channel model by considering turbulence-induced Scintillation Attenuation(SA).Then,the Bit Error Rate(BER)during turbulence of the NLOS UV communication system with On-Off Keying(OOK)modulation and Maximum Likelihood(ML)detection is analysed and compared with that in free space without turbulence.The BER dependence is also analysed for different factors,including the refractive index structure parameter,transceiver range,pointing angles,transmitted power,and data rate.
基金funded by the Earthquake Commission of New ZealandThe Institute of GNS ScienceMassey University
文摘In 2013 a new collaborative center was established in Wellington, New Zealand to focus on integrating resilience research with the region’s community disaster resilience strategy. An earlier study with parties to this center had indicated that researcher and practitioner groups were divided by attention to their own immediate knowledge and skills, but agreed there was a need to maximize community resilience benefits amongst a regional population. An action research workshop of researchers and practitioners used a visual logic model to focus on the pragmatic benefits of improving community resilience. The visual logic model was used to design research activities that would improve the regional community resilience strategy, which was still in an early implementation phase.Ten of 14 workshop participants were interviewed following the workshop. Statistical content analysis of interview data highlighted certain strengths of the action research process: visual monitoring and evaluation planning was a catalyst for complicated conversations between two very different groups of professionals; and researchers became more focused on practical issues as a result. Other findings suggested that in future collaborative researchgovernance would benefit from wider cycles of strategic intelligence, enhanced research contributions, and the use of different information formats for different purposes.Different formats for different purposes should also be considered when developing and implementing large-scale disaster risk reduction policies and strategies.
