为对残煤复采综放工作面液压支架进行合理的选型,以晋煤仙泉煤矿2201残煤复采综放工作面为研究背景,采用现场地质资料调查、理论分析、数值模拟等方法,对该地质条件下的工作面液压支架进行合理的选型。结果表明:复采工作面过空巷时形成...为对残煤复采综放工作面液压支架进行合理的选型,以晋煤仙泉煤矿2201残煤复采综放工作面为研究背景,采用现场地质资料调查、理论分析、数值模拟等方法,对该地质条件下的工作面液压支架进行合理的选型。结果表明:复采工作面过空巷时形成的基本顶长关键块长度为空巷宽度、煤柱失稳极限宽度、基本顶周期来压步距之和,并通过分析最终确定的支架合理工作阻力为9 532 k N、初撑力为7 144 k N(31.5 MPa)、中心距为1 750 mm、支架高度为2.5~4.2m。通过研究结果结合复采工作面现场情况,选定ZFY10200/25/42两柱掩护式放顶煤液压支架为合理架型。展开更多
针对正交时频空(Orthogonal Time Frequency Space,OTFS)调制系统采用矩形窗函数时,信道矩阵结构复杂导致的鲁棒性差的问题,提出了一种基于时域处理和酉近似消息传递的检测算法。该算法首先添加循环前缀,将时域信道转换为分块对角矩阵;...针对正交时频空(Orthogonal Time Frequency Space,OTFS)调制系统采用矩形窗函数时,信道矩阵结构复杂导致的鲁棒性差的问题,提出了一种基于时域处理和酉近似消息传递的检测算法。该算法首先添加循环前缀,将时域信道转换为分块对角矩阵;然后应用酉变换和近似消息传递建立迭代检测算法。仿真结果表明,所提检测算法能够在不增加复杂度的条件下有效提升检测精度和鲁棒性,特别是存在信道编码的条件下表现出2 dB的性能增益,使得该算法更适用于杂散多径、高速移动等环境,具有较高的应用价值。展开更多
A wide variety of algorithms have been developed to monitor aerosol burden from satellite images. Still, few solutions currently allow for real-time and efficient retrieval of aerosol optical thickness （AOT）, mainly...A wide variety of algorithms have been developed to monitor aerosol burden from satellite images. Still, few solutions currently allow for real-time and efficient retrieval of aerosol optical thickness （AOT）, mainly due to the extremely large volume of computation necessary for the numeric solution of atmospheric radiative transfer equations. Taking into account the efforts to exploit the SYNergy of Terra and Aqua Modis （SYNTAM, an AOT retrieval algorithm）, we present in this paper a novel method to retrieve AOT from Moderate Resolution Imaging Spectroradiometer （MODIS） satellite images, in which the strategy of block partition and collective communication was taken, thereby maximizing load balance and reducing the overhead time during inter-processor communication. Experiments were carried out to retrieve AOT at 0.44, 0.55, and 0.67μm of MODIS/Terra and MODIS/Aqua data, using the parallel SYNTAM algorithm in the IBM System Cluster 1600 deployed at China Meteorological Administration （CMA）. Results showed that parallel implementation can greatly reduce computation time, and thus ensure high parallel efficiency. AOT derived by parallel algorithm was validated against measurements from ground-based sun-photometers; in all cases, the relative error range was within 20%, which demonstrated that the parallel algorithm was suitable for applications such as air quality monitoring and climate modeling.展开更多
文摘为对残煤复采综放工作面液压支架进行合理的选型,以晋煤仙泉煤矿2201残煤复采综放工作面为研究背景,采用现场地质资料调查、理论分析、数值模拟等方法,对该地质条件下的工作面液压支架进行合理的选型。结果表明:复采工作面过空巷时形成的基本顶长关键块长度为空巷宽度、煤柱失稳极限宽度、基本顶周期来压步距之和,并通过分析最终确定的支架合理工作阻力为9 532 k N、初撑力为7 144 k N(31.5 MPa)、中心距为1 750 mm、支架高度为2.5~4.2m。通过研究结果结合复采工作面现场情况,选定ZFY10200/25/42两柱掩护式放顶煤液压支架为合理架型。
文摘针对正交时频空(Orthogonal Time Frequency Space,OTFS)调制系统采用矩形窗函数时,信道矩阵结构复杂导致的鲁棒性差的问题,提出了一种基于时域处理和酉近似消息传递的检测算法。该算法首先添加循环前缀,将时域信道转换为分块对角矩阵;然后应用酉变换和近似消息传递建立迭代检测算法。仿真结果表明,所提检测算法能够在不增加复杂度的条件下有效提升检测精度和鲁棒性,特别是存在信道编码的条件下表现出2 dB的性能增益,使得该算法更适用于杂散多径、高速移动等环境,具有较高的应用价值。
基金supported partly by the Ministry of Science and Technology of the People’s Republic of China (Grant Nos.2007CB714407, and 2008ZX10004012)the Special Funds for Basic Research in CAMS of CMA (Grant No. 2007Y001)State Key Laboratory of Remote Sensing Sciences (Grant No.07S00502CX)
文摘A wide variety of algorithms have been developed to monitor aerosol burden from satellite images. Still, few solutions currently allow for real-time and efficient retrieval of aerosol optical thickness （AOT）, mainly due to the extremely large volume of computation necessary for the numeric solution of atmospheric radiative transfer equations. Taking into account the efforts to exploit the SYNergy of Terra and Aqua Modis （SYNTAM, an AOT retrieval algorithm）, we present in this paper a novel method to retrieve AOT from Moderate Resolution Imaging Spectroradiometer （MODIS） satellite images, in which the strategy of block partition and collective communication was taken, thereby maximizing load balance and reducing the overhead time during inter-processor communication. Experiments were carried out to retrieve AOT at 0.44, 0.55, and 0.67μm of MODIS/Terra and MODIS/Aqua data, using the parallel SYNTAM algorithm in the IBM System Cluster 1600 deployed at China Meteorological Administration （CMA）. Results showed that parallel implementation can greatly reduce computation time, and thus ensure high parallel efficiency. AOT derived by parallel algorithm was validated against measurements from ground-based sun-photometers; in all cases, the relative error range was within 20%, which demonstrated that the parallel algorithm was suitable for applications such as air quality monitoring and climate modeling.
