Turbo码是一种常用的信道编码方式,正确识别Turbo码首先要正确识别其子递归系统卷积(recursive system convolutional,RSC)码,由于信道噪声与干扰引发误码,这就要求识别算法具有良好的抗误码性能以及识别能力。利用解调软判决序列,通过...Turbo码是一种常用的信道编码方式,正确识别Turbo码首先要正确识别其子递归系统卷积(recursive system convolutional,RSC)码,由于信道噪声与干扰引发误码,这就要求识别算法具有良好的抗误码性能以及识别能力。利用解调软判决序列,通过编码码元约束方程,构建指数形式的代价函数模型,将识别RSC码的生成矩阵问题转化为求解代价函数全域极值的最优化问题,最后在共轭梯度法的基础上,采用新的PRP步长因子来寻找全域极值点。仿真结果表明,所提算法与现有算法相比,收敛速度更快,在低信噪比下也有良好的识别能力。展开更多
Global value chains(GVCs)have entered a new stage of restructuring characterized by trends towards localization,regionalization and diversification.These trends can be attributed to the evolution of the international ...Global value chains(GVCs)have entered a new stage of restructuring characterized by trends towards localization,regionalization and diversification.These trends can be attributed to the evolution of the international division,irrational responses to crisis shocks,and trade protectionism.In this context,China’s industrial and supply chain upgrades face both opportunities and challenges which require navigating the adverse effects of industrial re-shoring,unfair technology competition,and changes in the global industrial layout.Yet,such challenges may create pressures for China to accelerate innovation,overcome the low-end lock-up effect by creating regional value chains,and broaden international cooperation.China needs to explore an effective strategy to defuse risks and seize opportunities.On one hand,China should influence the restructuring of GVCs evolution and strengthen its supply chains by playing an active role in economic globalization and the international division.On the other hand,China should proactively respond to GVCs restructuring amid rising trade protectionism,defuse risks from trade protectionism by opening wider to the outside world,and strive to upgrade industrial and supply chains while enhancing the security and stability of their nation.展开更多
The full-space transient electromagnetic response of water-filled goaves in coal mines were numerically modeled. Traditional numerical modeling methods cannot be used to simulate the underground full-space transient e...The full-space transient electromagnetic response of water-filled goaves in coal mines were numerically modeled. Traditional numerical modeling methods cannot be used to simulate the underground full-space transient electromagnetic field. We used multiple transmitting loops instead of the traditional single transmitting loop to load the transmitting loop into Cartesian grids. We improved the method for calculating the z-component of the magnetic field based on the characteristics of full space. Then, we established the full- space 3D geoelectrical model using geological data for coalmines. In addition, the transient electromagnetic responses of water-filled goaves of variable shape at different locations were simulated by using the finite-difference time-domain （FDTD） method. Moreover, we evaluated the apparent resistivity results. The numerical modeling results suggested that the resistivity differences between the coal seam and its roof and floor greatly affect the distribution of apparent resistivity, resulting in nearly circular contours with the roadway head at the center. The actual distribution of apparent resistivity for different geoelectrical models of water in goaves was consistent with the models. However, when the goal water was located in one side, a false low-resistivity anomaly would appear on the other side owing to the full-space effect but the response was much weaker. Finally, the modeling results were subsequently confirmed by drilling, suggesting that the proposed method was effective.展开更多
文摘Turbo码是一种常用的信道编码方式,正确识别Turbo码首先要正确识别其子递归系统卷积(recursive system convolutional,RSC)码,由于信道噪声与干扰引发误码,这就要求识别算法具有良好的抗误码性能以及识别能力。利用解调软判决序列,通过编码码元约束方程,构建指数形式的代价函数模型,将识别RSC码的生成矩阵问题转化为求解代价函数全域极值的最优化问题,最后在共轭梯度法的基础上,采用新的PRP步长因子来寻找全域极值点。仿真结果表明,所提算法与现有算法相比,收敛速度更快,在低信噪比下也有良好的识别能力。
文摘Global value chains(GVCs)have entered a new stage of restructuring characterized by trends towards localization,regionalization and diversification.These trends can be attributed to the evolution of the international division,irrational responses to crisis shocks,and trade protectionism.In this context,China’s industrial and supply chain upgrades face both opportunities and challenges which require navigating the adverse effects of industrial re-shoring,unfair technology competition,and changes in the global industrial layout.Yet,such challenges may create pressures for China to accelerate innovation,overcome the low-end lock-up effect by creating regional value chains,and broaden international cooperation.China needs to explore an effective strategy to defuse risks and seize opportunities.On one hand,China should influence the restructuring of GVCs evolution and strengthen its supply chains by playing an active role in economic globalization and the international division.On the other hand,China should proactively respond to GVCs restructuring amid rising trade protectionism,defuse risks from trade protectionism by opening wider to the outside world,and strive to upgrade industrial and supply chains while enhancing the security and stability of their nation.
基金supported by the National Key Scientific Instrument and Equipment Development Project(No.2011YQ03013307)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education InstitutionsKey Laboratory of Coal Resources Exploration and Comprehensive Utilization,Ministry of Land and Resources
文摘The full-space transient electromagnetic response of water-filled goaves in coal mines were numerically modeled. Traditional numerical modeling methods cannot be used to simulate the underground full-space transient electromagnetic field. We used multiple transmitting loops instead of the traditional single transmitting loop to load the transmitting loop into Cartesian grids. We improved the method for calculating the z-component of the magnetic field based on the characteristics of full space. Then, we established the full- space 3D geoelectrical model using geological data for coalmines. In addition, the transient electromagnetic responses of water-filled goaves of variable shape at different locations were simulated by using the finite-difference time-domain （FDTD） method. Moreover, we evaluated the apparent resistivity results. The numerical modeling results suggested that the resistivity differences between the coal seam and its roof and floor greatly affect the distribution of apparent resistivity, resulting in nearly circular contours with the roadway head at the center. The actual distribution of apparent resistivity for different geoelectrical models of water in goaves was consistent with the models. However, when the goal water was located in one side, a false low-resistivity anomaly would appear on the other side owing to the full-space effect but the response was much weaker. Finally, the modeling results were subsequently confirmed by drilling, suggesting that the proposed method was effective.
