首先证明了非差网络实时动态定位（real time kinematic,RTK）与广域精密单点定位（precise point positioning,PPP）-RTK用户模糊度解算结果的一致性,并利用前者的模糊度可快速固定而后者无需用户与基准站间实时数据通讯的特性,提出了...首先证明了非差网络实时动态定位（real time kinematic,RTK）与广域精密单点定位（precise point positioning,PPP）-RTK用户模糊度解算结果的一致性,并利用前者的模糊度可快速固定而后者无需用户与基准站间实时数据通讯的特性,提出了一套适用于大规模用户的非差网络RTK服务模式。按照新模式处理了湖北省连续运行参考站系统的一组实时数据,并与采用原有服务模式的解算结果进行比较,定量评估了新服务模式在实时应用中的定位精度及可靠性。结果表明,对于基准站间平均距离约为120km的区域增强网,网内用户一般只需几个历元进行初始化,便可获得平面方向1-2cm、高程方向6.3cm的快速实时精密定位服务;并且一旦用户完成模糊度初始化,区域增强系统可同时服务的用户数量将不再受限制;与采用原有非差网络RTK模式时94.274%的服务有效性相比,新模式的服务有效性高达99.914%,有效填充了原有服务模式下由于用户周边基准站区域增强信息中断引起的“服务空隙”。展开更多
Mass customization (MC) is emerging as a competitive advantage of firms with the intensified competition and economic globalization.As a key feature of MC,postponement strategy postpones activities in the supply chain...Mass customization (MC) is emerging as a competitive advantage of firms with the intensified competition and economic globalization.As a key feature of MC,postponement strategy postpones activities in the supply chain until customer orders are received.This article provides a review of the literature on postponement from perspectives of research content and methodology.Taking postponement as a supply chain concept,this article specifically reclassifies the postponement applications according to the positioning of the customer order decoupling point (CODP) in the supply chain.Future directions for postponement research are also suggested in this article.展开更多
This study promotes application of Augmented Reality （AR）, whose properties can handle multiple sensory that heightens its quality of performances, affections in first time users, and introduces the possibility and ...This study promotes application of Augmented Reality （AR）, whose properties can handle multiple sensory that heightens its quality of performances, affections in first time users, and introduces the possibility and guideline in mass production through the development of＂Augmented Reality Band＂, a gadget based on AR system that allows users to interact with virtual music instruments to make music through the system that analyze printed marker on the shirt. The system is developed by using FLAR Toolkit and made accessible via AR band website. The user can run the system online from anywhere by wearing the shirt printed with embedded musical instruments AR code. In order to promote AR Band performances, the authors assessed the quality of the system from technical professionals. It has been found out that the quality level is very high （4.64/5.00） and the user satisfaction evaluated by sample group has been found in a satisfied level （4.22/5.00）. In summary, AR Band has proven its performances to enhance user satisfaction and its further development and adaptation is under discussion and suggestion section provided at the end.展开更多
Acquisition of accurate channel state information （CSI） at transmitters results in a huge pilot overhead in massive multiple input multiple output （MIMO） systems due to the large number of antennas in the base sta...Acquisition of accurate channel state information （CSI） at transmitters results in a huge pilot overhead in massive multiple input multiple output （MIMO） systems due to the large number of antennas in the base station （BS）. To reduce the overwhelming pilot overhead in such systems, a structured joint channel estimation scheme employing compressed sensing （CS） theory is proposed. Specifically, the channel sparsity in the angular domain due to the practical scattering environment is analyzed, where common sparsity and individual sparsity structures among geographically neighboring users exist in multi-user massive MIMO systems. Then, by equipping each user with multiple antennas, the pilot overhead can be alleviated in the framework of CS and the channel estimation quality can be improved. Moreover, a structured joint matching pursuit （SJMP） algorithm at the BS is proposed to jointly estimate the channel of users with reduced pilot overhead. Furthermore, the probability upper bound of common support recovery and the upper bound of channel estimation quality using the proposed SJMP algorithm are derived. Simulation results demonstrate that the proposed SJMP algorithm can achieve a higher system performance than those of existing algorithms in terms of pilot overhead and achievable rate.展开更多
文摘首先证明了非差网络实时动态定位（real time kinematic,RTK）与广域精密单点定位（precise point positioning,PPP）-RTK用户模糊度解算结果的一致性,并利用前者的模糊度可快速固定而后者无需用户与基准站间实时数据通讯的特性,提出了一套适用于大规模用户的非差网络RTK服务模式。按照新模式处理了湖北省连续运行参考站系统的一组实时数据,并与采用原有服务模式的解算结果进行比较,定量评估了新服务模式在实时应用中的定位精度及可靠性。结果表明,对于基准站间平均距离约为120km的区域增强网,网内用户一般只需几个历元进行初始化,便可获得平面方向1-2cm、高程方向6.3cm的快速实时精密定位服务;并且一旦用户完成模糊度初始化,区域增强系统可同时服务的用户数量将不再受限制;与采用原有非差网络RTK模式时94.274%的服务有效性相比,新模式的服务有效性高达99.914%,有效填充了原有服务模式下由于用户周边基准站区域增强信息中断引起的“服务空隙”。
基金National Natural Science Foundation of ChinaMinistry of Science&Technology of China and Scientific and Technological Innovation Foundation for Graduate Students of Huazhong University of Science and Technology for the financial support through grant 79970026,a National 863/CIMS Scheme grant 2001AA414110 and grant YCJ-02-005 respectively.
文摘Mass customization (MC) is emerging as a competitive advantage of firms with the intensified competition and economic globalization.As a key feature of MC,postponement strategy postpones activities in the supply chain until customer orders are received.This article provides a review of the literature on postponement from perspectives of research content and methodology.Taking postponement as a supply chain concept,this article specifically reclassifies the postponement applications according to the positioning of the customer order decoupling point (CODP) in the supply chain.Future directions for postponement research are also suggested in this article.
文摘This study promotes application of Augmented Reality （AR）, whose properties can handle multiple sensory that heightens its quality of performances, affections in first time users, and introduces the possibility and guideline in mass production through the development of＂Augmented Reality Band＂, a gadget based on AR system that allows users to interact with virtual music instruments to make music through the system that analyze printed marker on the shirt. The system is developed by using FLAR Toolkit and made accessible via AR band website. The user can run the system online from anywhere by wearing the shirt printed with embedded musical instruments AR code. In order to promote AR Band performances, the authors assessed the quality of the system from technical professionals. It has been found out that the quality level is very high （4.64/5.00） and the user satisfaction evaluated by sample group has been found in a satisfied level （4.22/5.00）. In summary, AR Band has proven its performances to enhance user satisfaction and its further development and adaptation is under discussion and suggestion section provided at the end.
基金Project supported by the Fundamental Research Funds for the Cen- tral Universities （No. HIT.MKSTISP.2016 13） and the National Natural Science Foundation of China （No. 61671176）
文摘Acquisition of accurate channel state information （CSI） at transmitters results in a huge pilot overhead in massive multiple input multiple output （MIMO） systems due to the large number of antennas in the base station （BS）. To reduce the overwhelming pilot overhead in such systems, a structured joint channel estimation scheme employing compressed sensing （CS） theory is proposed. Specifically, the channel sparsity in the angular domain due to the practical scattering environment is analyzed, where common sparsity and individual sparsity structures among geographically neighboring users exist in multi-user massive MIMO systems. Then, by equipping each user with multiple antennas, the pilot overhead can be alleviated in the framework of CS and the channel estimation quality can be improved. Moreover, a structured joint matching pursuit （SJMP） algorithm at the BS is proposed to jointly estimate the channel of users with reduced pilot overhead. Furthermore, the probability upper bound of common support recovery and the upper bound of channel estimation quality using the proposed SJMP algorithm are derived. Simulation results demonstrate that the proposed SJMP algorithm can achieve a higher system performance than those of existing algorithms in terms of pilot overhead and achievable rate.
