Between 2005 and 2015,the Brazilian real estate market experienced strong growth,driven by the stable scenario of the Brazilian economy and policies to encourage real estate credit.With this demand,the companies of th...Between 2005 and 2015,the Brazilian real estate market experienced strong growth,driven by the stable scenario of the Brazilian economy and policies to encourage real estate credit.With this demand,the companies of the sector sought to be more competitive in the market.One of the measures adopted is the search for more efficient executive processes.While the traditional manual methodology for underlayment predominates in the country’s construction sites,a self-levelling underlayment presents a tendency towards mechanization of executive construction procedures.This paper aims to present a case study of a residential construction in Rio de Janeiro,which used self-levelling underlayment technology.Comparisons regarding cost and productivity of both methodologies were made to evaluate the viability of the self-levelling underlayment in future construction sites.Data obtained from other constructions were used to estimate the productivity and cost of the traditional underlayment levelling.The results demonstrate that the use of self-levelling underlayment has potential to be widespread and used in the constructions in Brazil.展开更多
Purpose:Myringoplasty aims to improve hearing and prevent otorrhea,making graft uptake rates and hearing crucial considerations.This study analyzed the factors associated with unsuccessful graft uptake and hearing imp...Purpose:Myringoplasty aims to improve hearing and prevent otorrhea,making graft uptake rates and hearing crucial considerations.This study analyzed the factors associated with unsuccessful graft uptake and hearing improvement to guide the selection of optimal surgical approaches for myringoplasty.Methods:We retrospectively reviewed 56 ears with chronic otitis media.All patients were followed up for>6 months after tympanic membrane closure surgery.We compared the underlay method using the transcanal approach with the inlay method using the retroauricular approach for myringoplasty in patients with chronic otitis media.The underlay and inlay methods were used for 23 and 33 ears,respectively.The primary outcomes were graft uptake rate and hearing improvement.Additionally,factors such as the location of tympanic membrane perforation,patient age,and the degree of mastoid development were evaluated.Results:The perforation rate was high when the transcanal underlay method was employed to repair perforations in the anterior inferior quadrant.Both the underlay and inlay methods significantly improved hearing.However,the success rate of the inlay method was lower.Within the cases performed using the inlay method,outcomes tended to be poorer in older age groups.There were no significant differences in surgical success rates related to mastoid development.Conclusion:The inlay method using the retroauricular approach is a favorable option for repairing perforations involving the anterior inferior quadrant.However,older patients presented lower rates of hearing improvement when the inlay method was used.展开更多
国家新型基础设施建设给各运营商带来了新的发展契机,纷纷布局以云网融合为特征的数据中心建设。本文重点分析运营商如何打造云网一体化网络服务提供点(Point of Presence,POP),满足不同客户差异化的入云或云间组网需求,实现云网能力端...国家新型基础设施建设给各运营商带来了新的发展契机,纷纷布局以云网融合为特征的数据中心建设。本文重点分析运营商如何打造云网一体化网络服务提供点(Point of Presence,POP),满足不同客户差异化的入云或云间组网需求,实现云网能力端到端快速贯通,云资源池快速规模化部署,缩短云资源池或数据中心接入网络的建设和开通周期。展开更多
传统软件定义广域网络(software-defined wide area network,SD-WAN)通过虚拟扩展局域网(virtual extensible local area network,VXLAN)/通用路由封装(generic routing encapsulation,GRE)/互联网安全协议(internet protocol security,...传统软件定义广域网络(software-defined wide area network,SD-WAN)通过虚拟扩展局域网(virtual extensible local area network,VXLAN)/通用路由封装(generic routing encapsulation,GRE)/互联网安全协议(internet protocol security,IPSec)等隧道技术建立Overlay虚拟网络连接,网络质量受限于Underlay网络。为解决传统SD-WAN技术无法感知网络底层业务特性的问题,对SRv6协议进行研究,提出基于SRv6技术的新一代SD-WAN技术,并基于现网搭建测试环境进行验证,以期为相关人员提供参考。展开更多
认知无线电通过与MIMO(Multi-Input Multi-Output)、OFDM(Orthogonal Frequency Division Multiplexing)、超宽带、协作通信等技术融合来改善频谱利用率.而认知MIMO是认知无线电和MIMO技术的融合,虽然具有干扰抑制、抗多径衰落、空间分...认知无线电通过与MIMO(Multi-Input Multi-Output)、OFDM(Orthogonal Frequency Division Multiplexing)、超宽带、协作通信等技术融合来改善频谱利用率.而认知MIMO是认知无线电和MIMO技术的融合,虽然具有干扰抑制、抗多径衰落、空间分集和复用等优势,但是由于underlay共享方式中干扰温度约束的存在,导致发送预编码矩阵之间相互耦合,因此该技术在underlay干扰网络中难以获得最优的传输性能.针对该问题,通过交替迭代的方式,结合Rayleigh-Ritz定理和凸优化理论,推导了最优收发矩阵之间的迭代关系,提出一种最优干扰对齐算法.该算法利用Lagrange部分对偶方式来去除干扰温度约束,并采用次梯度投影法更新Lagrange变量,克服了已有半正定松弛算法因忽略矩阵秩约束而导致速率性能下降的缺陷.理论分析和数值仿真验证了算法的有效性,结果表明所提算法可实现网络可达速率和的最大化.展开更多
针对underlay认知无线电中时频重叠正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)信号的信噪比(Signal to Noise Ratio,SNR)难以估计的问题,提出了一种基于循环自相关特性的时频重叠OFDM信噪比盲估计方法.该方法提取...针对underlay认知无线电中时频重叠正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)信号的信噪比(Signal to Noise Ratio,SNR)难以估计的问题,提出了一种基于循环自相关特性的时频重叠OFDM信噪比盲估计方法.该方法提取接收信号的循环自相关函数截面中的离散谱线估计出分量信号的总功率,并结合时延和循环频率均为零时的离散谱线估计出时频重叠OFDM信号的信噪比.仿真结果表明,在无需先验信息的情况下,当SNR大于-7d B时,所提方法估计的均方误差小于0.1,并且对分量信号的功率比和频谱重叠率具有稳健性.展开更多
As one of the key technologies for the fifth generation(5G) wireless networks,device-to-device(D2D) communications allow user equipment(UE) in close proximity to communicate with each other directly.Forwarded by a rel...As one of the key technologies for the fifth generation(5G) wireless networks,device-to-device(D2D) communications allow user equipment(UE) in close proximity to communicate with each other directly.Forwarded by a relay,the relay-aided D2D(RA-D2D) communications can not only be applied to communications in much longer distance but also achieve a high quality of service(Qo S) .In this paper,we first propose a two-layer system model allowing RA-D2 D links to underlay traditional cellular uplinks.Then we maximize the energy efficiency of the RA-D2 D link while satisfying the minimum data-rate of the cellular link.The optimal transmit power at both D2 D transmitter and D2 D relay sides is obtained by transforming the nonlinear fractional programming into a nonlinear parameter programming.Simulation results show that our proposed power allocation method is more energy efficient than the existing works,and the proposed RA-D2 D scheme outperformed direct D2 D scheme when the distance between two D2 D users is longer.展开更多
文摘Between 2005 and 2015,the Brazilian real estate market experienced strong growth,driven by the stable scenario of the Brazilian economy and policies to encourage real estate credit.With this demand,the companies of the sector sought to be more competitive in the market.One of the measures adopted is the search for more efficient executive processes.While the traditional manual methodology for underlayment predominates in the country’s construction sites,a self-levelling underlayment presents a tendency towards mechanization of executive construction procedures.This paper aims to present a case study of a residential construction in Rio de Janeiro,which used self-levelling underlayment technology.Comparisons regarding cost and productivity of both methodologies were made to evaluate the viability of the self-levelling underlayment in future construction sites.Data obtained from other constructions were used to estimate the productivity and cost of the traditional underlayment levelling.The results demonstrate that the use of self-levelling underlayment has potential to be widespread and used in the constructions in Brazil.
文摘Purpose:Myringoplasty aims to improve hearing and prevent otorrhea,making graft uptake rates and hearing crucial considerations.This study analyzed the factors associated with unsuccessful graft uptake and hearing improvement to guide the selection of optimal surgical approaches for myringoplasty.Methods:We retrospectively reviewed 56 ears with chronic otitis media.All patients were followed up for>6 months after tympanic membrane closure surgery.We compared the underlay method using the transcanal approach with the inlay method using the retroauricular approach for myringoplasty in patients with chronic otitis media.The underlay and inlay methods were used for 23 and 33 ears,respectively.The primary outcomes were graft uptake rate and hearing improvement.Additionally,factors such as the location of tympanic membrane perforation,patient age,and the degree of mastoid development were evaluated.Results:The perforation rate was high when the transcanal underlay method was employed to repair perforations in the anterior inferior quadrant.Both the underlay and inlay methods significantly improved hearing.However,the success rate of the inlay method was lower.Within the cases performed using the inlay method,outcomes tended to be poorer in older age groups.There were no significant differences in surgical success rates related to mastoid development.Conclusion:The inlay method using the retroauricular approach is a favorable option for repairing perforations involving the anterior inferior quadrant.However,older patients presented lower rates of hearing improvement when the inlay method was used.
文摘国家新型基础设施建设给各运营商带来了新的发展契机,纷纷布局以云网融合为特征的数据中心建设。本文重点分析运营商如何打造云网一体化网络服务提供点(Point of Presence,POP),满足不同客户差异化的入云或云间组网需求,实现云网能力端到端快速贯通,云资源池快速规模化部署,缩短云资源池或数据中心接入网络的建设和开通周期。
文摘传统软件定义广域网络(software-defined wide area network,SD-WAN)通过虚拟扩展局域网(virtual extensible local area network,VXLAN)/通用路由封装(generic routing encapsulation,GRE)/互联网安全协议(internet protocol security,IPSec)等隧道技术建立Overlay虚拟网络连接,网络质量受限于Underlay网络。为解决传统SD-WAN技术无法感知网络底层业务特性的问题,对SRv6协议进行研究,提出基于SRv6技术的新一代SD-WAN技术,并基于现网搭建测试环境进行验证,以期为相关人员提供参考。
文摘认知无线电通过与MIMO(Multi-Input Multi-Output)、OFDM(Orthogonal Frequency Division Multiplexing)、超宽带、协作通信等技术融合来改善频谱利用率.而认知MIMO是认知无线电和MIMO技术的融合,虽然具有干扰抑制、抗多径衰落、空间分集和复用等优势,但是由于underlay共享方式中干扰温度约束的存在,导致发送预编码矩阵之间相互耦合,因此该技术在underlay干扰网络中难以获得最优的传输性能.针对该问题,通过交替迭代的方式,结合Rayleigh-Ritz定理和凸优化理论,推导了最优收发矩阵之间的迭代关系,提出一种最优干扰对齐算法.该算法利用Lagrange部分对偶方式来去除干扰温度约束,并采用次梯度投影法更新Lagrange变量,克服了已有半正定松弛算法因忽略矩阵秩约束而导致速率性能下降的缺陷.理论分析和数值仿真验证了算法的有效性,结果表明所提算法可实现网络可达速率和的最大化.
文摘针对underlay认知无线电中时频重叠正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)信号的信噪比(Signal to Noise Ratio,SNR)难以估计的问题,提出了一种基于循环自相关特性的时频重叠OFDM信噪比盲估计方法.该方法提取接收信号的循环自相关函数截面中的离散谱线估计出分量信号的总功率,并结合时延和循环频率均为零时的离散谱线估计出时频重叠OFDM信号的信噪比.仿真结果表明,在无需先验信息的情况下,当SNR大于-7d B时,所提方法估计的均方误差小于0.1,并且对分量信号的功率比和频谱重叠率具有稳健性.
基金supported by the ZTE Corp under Grant CON1412150018the Natural Science Foundation of China under Grant 61572389 and 61471361
文摘As one of the key technologies for the fifth generation(5G) wireless networks,device-to-device(D2D) communications allow user equipment(UE) in close proximity to communicate with each other directly.Forwarded by a relay,the relay-aided D2D(RA-D2D) communications can not only be applied to communications in much longer distance but also achieve a high quality of service(Qo S) .In this paper,we first propose a two-layer system model allowing RA-D2 D links to underlay traditional cellular uplinks.Then we maximize the energy efficiency of the RA-D2 D link while satisfying the minimum data-rate of the cellular link.The optimal transmit power at both D2 D transmitter and D2 D relay sides is obtained by transforming the nonlinear fractional programming into a nonlinear parameter programming.Simulation results show that our proposed power allocation method is more energy efficient than the existing works,and the proposed RA-D2 D scheme outperformed direct D2 D scheme when the distance between two D2 D users is longer.
